Kite Strings

1983/12
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SKYTING NO.20
DECEMBER 1983
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1983/12-01

SKYTING'S BIRTHDAY

It's hard to say when skyting was born. It was conceived during the summer of 1980, developed during the fall, written up for publication in December 1980, first published in Hang Gliding in April 1981, rejected by the established hang gliding community almost immediately, self-published in SKYTING NO. 1 in October 1981, reintroduced to the hang gliding community in Whole Air in March/April 1982, and promoted through the Skyting Newsletter since June 1982. By this time interest was growing rapidly as pilots began to realize the advantages of towing with a system based upon the skyting philosophy and theory.

Today, skyting is becoming more and more acceptable. In the towing dark ages B.S. (Before Skyting) most pilots were afraid to tow (and justifiably so), but today A.S. (After Skyting) too many pilots are taking a fearless attitude toward towing. I expect the towing fatalities to increase this next year because of general lack of respect for the dangers of towing among the increasing number of tow pilots. Don't you be one of these pilots. So far, no one who subscribes to the Skyting Newsletter has been killed. In fact, my own two broken arms are the worst case accidents reported by Skyting subscribers. Let's keep it that way. Since I have decided to completely terminate my research on broken arms, this means that the safety record of Skyting subscribers should increase dramatically in the next few years.

But I digress... we were trying to determine the birth date of Skyting. I guess to me, it is the day I finally put it all down on paper in a form ready for publication - that day back in December 1980. The exact date eludes me, but it was sometime during the Christmas Holidays. So if skyting was really born that day, then it is three years old this month. Happy Birthday, Skyting! And to you readers, I hope this birthday has helped make your hang gliding more enjoyable.

Which reminds me of another birthday we are celebrating this month, that of Jesus Christ. Happy Birthday, Jesus. And to your readers, I hope that His birthday and the price he paid to rectify your deliberate mistakes has made your life more blessed.

Merry Christmas

Donnell, Helen, and the girls
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1983/12-02

AUSTRALIA TOWING NEWS

by Denis Cummings
Singleton
AUSTRALIA

1. Early Nov. 1983 - South East Queensland.

Pilot's 2-release type bridle released from the body ring prematurely. Top rope release still secure. Pilot was at top of tow. Glider flipped over (tuck & tumble) and the king post collapsed. Pilot successfully deployed parachute and landed with only damage being to glider. It definitely pays to have had plenty of parachute experience.

- I personally dislike any double release system, preferring the single release, even if it means carrying the bridle during the rest of the flight.

2. Early Nov. 1983 - Central N.S.W.

Pilot placed flag material at end of rope, close to the bridle release. Pilot saw release give way when pulled and did not notice that flag material was caught in end of bridle. Pilot landed safely draging rope.

- Could have been fatal. Nothing should be loose around the bridle/tow rope junction which could foul the release. Beware also of using a carabiner instead of a ring at the end of the towline. They have a habit of snatching up any loose material that falls across their gate.

3. Some good news - 19th Nov. 1983 - Central N.S.W.

Bill Poole clocks up 78 km in a 4 hour flight while your's truly goes 127.5 km in a 5 hr flight.

Towing up 1200 ft (2,200 ASL) at 12:30 pm. yours truly and Ted McCord (Queensland pilot, avocardo grower, punt driver, sailplane pilot, and Rainbow Beach hang gliding "ranger") climbed to cloudbase at 9,500 ft ASL rather rapidly. The view of central N.S.W. for 100 km and more in each direction was all too much for Ted, who had little idea of the area. Ted flew around the strip for about 2 hours having a ball.

My original aim, having got up, was to try and fly back to the Hunter Valley, thus gaining some valuable points for the local club contest points (points only given for either take-off or landing within the Hunter Valley). After reaching Gunnedah, the easterly lower wind made me reconsider, and head more in a westerly direction. Although the wind above cloudbase (Now 9,500 - 10,000 ft ASL) was westerly, the general drift at 3,000 - 9,000 ft was from the east or nil. Good thermals (600-1000 fpm) were common, with some good sink patches in between. Some streeting (very inconsistent) seemed to form later, as the sky started to O/D. After some zig-zagging to stay near roads and avoid scrubby areas, the lift died and I enjoyed a pretty smooth final glide from about 9,000 ft towards the base of the Warrumbungle Ranges.

Bill, who took off later than me, and who had kept in contact with me most of the way, had flown a more direct route towards the Warrumbungles ("The lumpy hills on the horizon") before striking a large patch of the Pillaga Scrub which he baulked at crossing. The last lift was used at about 4:30/5:00 p.m. (Daylight Saving Time), so there was still, theoretically, about 2 or 3 hours of daylight left. Maybe next time it won't overdevelop!
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TOWLINE WEAR PROBLEMS
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1983/12-03

Dear Donnell,

We've been towing at Pike County Airport, a 4200 ft E-W site. 1500 ft towline, 7-900 ft releases. Mario and Greg got flights of about 1 hour an flew 6 airmiles over to our Route 35 ridge site. (Ridge wasn't soarable, so they just landed.) Got around 3000 ft above during flight. Mario got about 20 minute flight over airport during last Sunday's towing.

Noting considerable wear on towlines, knots. Perhaps if we reeled line up each time we might reduce wear somewhat. After line is released we unhook from tow vehicle, find glider end, and tow it back to start. Then we drive back and hook back up while next glider is getting hooked up.

Any ideas on towline conservation techniques?

Jerry Martin
Dayton, OH
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1983/12-04

Dear Jerry,

See Ted Gilmore's suggestions for reducing wear on splices. (SKYTING NO. 18.)

Yes, reeling up the line after each flight will reduce the wear on the line, but you will have to decide whether the savings is worth the time and effort. (Personally, I do like you and drag the line back each time, replacing it when it starts breaking before the weak link breaks. I consider the cost of replacing worn towline an operating expense like replacing the gasoline used by the tow vehicle.)

I use parachute shroudline instead of regular braided nylon or polypropolene rope because it has a sleeve over the load bearing strands. It is this sleeve, not the internal strands, which takes most of the wear. By the time the wearing gets through to the internal strands, the line looks so bad that it is obviously time to replace it.

Towline wear increases as the line becomes longer. In general, a 1500 ft line will wear three times as fast as a 500 ft line because it is being dragged three times as far after each flight.

The faster you drag the line back to takeoff, the faster it seems to wear out, so you might be able to reduce wear by driving back to takeoff more slowly.

If you can drag the line over grass instead of dirt, rock, or asphalt, it will last longer.

And finally, if you do not want to reel the line up after each flight and you have the man power, you might space your ground crew out, put some tension on the line, and carry it back to takeoff.

Does anyone else, out there, have suggestions for prolonging towline lifetime?

Donnell
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PROGRESS IN WATER TOWING AND THE "SKYTOUT"
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1983/12-05

Dear Donnell,

Sunday September 25th, 3:00 PM, sunny 65 degrees, wind SW 10-15 mph. Skyting reaches 2900 ft over water.

It's been a beautiful summer here on Lake Delta. Many hours have been spent in R&D, getting the bugs out and polishing up our act.

Mid-summer we lost easy access to a winch we had spent a month developing and which worked like a charm. (A long story.) Not wanting to take the time to build another winch, Dan, my main cohort in crime, and I, with the backing of two other pilots, drove to Toranto, Canada, and purchased a High Perspective Winch (Reel).

During the next month armed with a 19 ft 260 hp boat, our reel with 1700 ft of line (All they had in stock.) and floats for prone deep water takeoffs and landings, we towed our brains out. Our flights averaged 1000-1400 ft AGL using about 3 miles of lake. I have personally logged 32 tows to date and have, with Dan's help, introduced 9 area pilots to successful skyting experiences for, I would approximate, some 75 additional tows.

By the end of August, things were going like clock work. It was time for more rope. We needed a light weight braided polypro. It was not as easy to find as I thought it would be. After seeing Butch Pritchell's letter in SKYTING #16, I arranged to have him send me 3000 ft of 5/32 polypro line. Thanks, Butch! Adding this to another 1000 ft of 1/4 I had purchased gave us a total of 5,700 ft of rope. It was time to get high.

On our first attempt we achieved the flight described in the opening paragraph. Dan was in the glider, my 168 Javelin, and I was on the reel having had the most experience in that department. We used about 8 miles of lake and had 4000 plus ft of line out. Our only problem during the tow was a lack of communication. The leg signals we normally used could not be seen much over 2000 ft and the spotter with the binoculars was rendered ineffective because of the rough water. Towing Dan blind was no fun at all. I was very conservative. After the flight, Dan said that I could have been much hotter.

A second attempt to reach high altitude was postponed till we can establish glider-to-boat radio communications. Because of the wet conditions created by the water starts and landing, this would take some time and thought. So just for fun Dan gave me a silky smooth ride to 2,250 ft. What a great way to get high! I've towed both Emerson Bailey and Skyting. Conventional was towing, skyting is flying. Thank you, Donnell.

We have towed all summer with safety as our number one priority and have no injuries to report. The few mishaps that did occur were related to either the deep water prone takeoff that is a bit tricky at first, or to a Skytout, which I'll explain in a minute. I thank mother nature for being so forgiving when a manned glider meets water in a less than desirable orientation.

A word on glider handling. We have towed a 165 Comet, 168 Javelin, Condor, and Bobcat II. We have not experienced any significant handling problems, adverse yaw, etc. that in my opinion were not a result of pilot over-control.

A situation I have observed concerning pilot control is potentially very dangerous without proper use of a weak link or release mechanism. I have had to release a pilot from a static line tow on two occasions. We haven't worked out a way to use a weak link in a static line situation and still have a boat release, which we like to have for a pilot's first few starts. The pressure built up during a deep water prone takeoff is much to great for a reasonable weak link. A weak link can be used with the reel which does not utilize a release in the boat.

Back to my releasing of the pilot from tow. The pilot was entering into what looked, smelt, and tasted like the makings of the classic lockout.

If I may take the liberty let me coin a new word: "Skytout" - a lockout prevented from proceeding to a point where there is a continued loss of glider control by a functtioning weak link.

What occurred in each case was what, I see, as a pilot induced overriding of the skyting bridle's self-correcting function in roll. After banking off to one side the pilot, instead of reacting normally and moving his body to the proper side of the control bar with the aid of the bridle's lower rope, resists the pull of the body line and freezes into a resisting position. The lower line is then "attached to the base tube" through the pilot's rigid resisting body. The roll is then aggravated as in the conventional tow system where the bottom line is attached to the base tube.

The pilot was not reacting properly and was following some instinct to resist a pulling force. In both instances, after the pilot was released (altitudes were below 50 ft), the pilot did not react quickly enough to level the glider and spiraled into the very very forgiving water. No damage to human or glider - just my central nervous system. Please - Please! - be aware of this possibility and watch for a learning pilot's tendency to resist the pull of the body line.

I observed a third skytout in Elmira, N.Y. at the Free Flight Hang Gliding Festival. Eighty-seven pilots showed up on Labor Day weekend for the competition, a truly super event. Rob Kells, with the help of Rich Pfeiffer, was giving aero-towing and aerobatic demonstrations. On the second day, a Canadian tow pilot experienced a skytout shortly after takeoff during a right hand turn. Rich Pfeiffer reported the incident in Skyting #18 (See "Pop-the-Whip Problem). In my discussions with the pilot and the others after the flight it was felt that the above mentioned overriding of the bridle's self-correcting function may have caused or influenced the situation. The pilot was not clear as to exactly what had happened. Was it a Pop-the-Whip or a bridle override - or could they be the same thing? We have towed with the boat making tight turns of approximately 100 yards diameter with no problem. I know that a whip behind a boat can be controlled by the skier. It needs only continue if the skier's body position resists the pull of the boat. If the skier "unfreezes" to release this resistance and leans to turn toward the boat, the whip ends.

As to the impossibility of the glider pilot's ability to turn the glider back on track... It is my recollection that the weak link was praised for releasing the glider and pilot before a serious situation developed. Was there a potential correction possible? Was the pilot in a classic lockout? Thanks to the weak link we need never really find out. He was in a Skytout.

My experiences have demonstrated to me that this system called Skyting has made towing a flexwing, in order to overcome gravity, as safe as it can be. I must caution, though, regardless of the cause, keep in mind that it is possible for a pilot to fly the glider into a Skytout - a situation the skyting system's design, if followed, is able to handle.

We've learned a lot this summer about equipment needed for deep water boat towing. I believe we have a system which will now allow us to give safe instruction (Dan's certified, and I'll be by spring) to Hot Hang I pilots. If you would like, Donnell, I will start putting together an article on the specifics of our equipment and technique. We are waiting anxiously for the return of our warm waters here in the North Country.

This winter we hope to use the reel for some land towing and Flip has purchased a Jet Wing so aero-towing is in our future.

Thanks again from me, Dan, Greg, Jay, Billy, Flip, Mike, Chris, Bruce, Waz, George, Dennis, Morry, and Bucko.

Don Boardman III
Rome, N.Y.
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1983/12-06

Dear Don,

Thanks for writing. Your discussion of the "Skytout" was very interesting.

I am a little puzzled about your problems towing with a winch using a long line. If your reel is "constant tension" as it feeds out line, why can not you set it on say 75 pounds and simply drive fast enough to keep feeding out line? The pilot should then be able to take care of everything else by controling his rate of climb and rate of travel. Once you have established the proper tension setting for what you like on a long line should be essentially the same.

Please do write up an article describing your equipment and techniques. You seem to know more about water towing than anyone else currently communicating with me. Also, communication seems to be dropping off after the insurge from summer flying experiences., so I could use some good material in the near future.

Donnell
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1983/12-07

AN ELECTRONIC TENSION GAUGE

by Denis Cummings
Singleton
AUSTRALIA

Although the hydraulic (brake cylinder style) tow tension measurer we made has worked accurately, and without failure, it had a few minor drawbacks. Spilt hydraulic fluid in the back of the car can be a nuisance. As well as lifting paintwork, it does nasty things to hang gliding gear. If hydraulic fluid gets onto any "man-carrying" equipment - REPLACE THE OILY GEAR - as the corrosive effect, even in the short term, may be fatal. Hang loops, harness ropes, parachutes, etc., are made from a variety of synthetic materials which may be weakened, dissolved, or destroyed by hydraulic fluid. Just "washing it off" is of no value due to possible absorbtion of the fluid into the material's fibers. Also, as my car was usually the only one with a tow bar, it ended up being used ALL THE TIME. Something not needing a tow bar was necessary.

Any commercial-type load measurers were priced at about $1,000.00 for the electronic gadgetry to read the load. Something slightly cheaper was needed. So after picking the brains of a couple of mates, annoying the hell out of a variety of electronic sales-rep. types, reading up a number of electronic publication, and a few weeks of experimenting, the "Mark 1" model was assembled, calibrated and tested. Apart from a few problems due to my inexperience with a soldering iron and minor limitations in the equipment, the unit was finally measuring the tow load successfully.

Spurred on by this success, it was now time to design "Mark 2" to do what "Mark 1" was doing, as well as bringing in a flashing red light and a buzzer to warn the driver that the desired tow load was reached or exceeded.

The initial, if cumbersome, design worked OK, but required 2 large batteries, a complicated balance/zero system and a 3rd (small) battery. Too complicated and unbalanced. Probably not too reliable either. After giving Mollo a 2 minute look at the circuit and a plea for "Help!", he picked up a pen and paper, did a lightning sketch, and said, "Try this!" I'll admit that I changed a few wires and a couple of components, but IT WORKED - on only one 9-volt battery and drawing less current than my "Hummingbird" Vario. Some more minor adjustments, and the circuitry and bits were loaded into a plastic box, calibrated and tested.

During testing, it was possible to set the light glowing and the buzzer giving a continuous hum at the desired tow load, and to start flashing and pulsing (beeping just like a vario if the desired tow load was exceeded. I am currently building the first small batch of these units, which should be available by the time this goes to print. They can still only be regarded as prototypes at this stage, as some future minor changes could be needed. These will cost you $150.00 plus $5.00 to cover postage and packing. Send to

Denis Cummings
16 Rawcliffe St.
Singleton 2330
Australia

A fuller description of the unit is provided below:

The "DC Tow Load"

The "DC Tow Load" is designed to give drivers of hang gliding towing vehicles an accurate visual display of the tow rope tension prior to and during towing proceedures, as well as a visual/audio warning when desired tow tension is being maintained and/or exceeded.

The system comprises: (a) A load sensor and cable and (b) a solid state electronic load measuring unit.

The load sensor connects between the towing vehicle and the tow rope. The cable connects the load sensor to the load measuring unit, with a 5-pin plug/socket.

The load measuring unit converts the input from the load sensor into a visual load readout on a large scale. This is usually placed directly in front of the tow vehicle. The unit has been calibrated internally and should not need any future calibration changes.

Power for the unit is via a 9 volt PP3 battery drawer. Correct polarity of the battery is necessary, and the circuit portection is internally provided to make the unit inoperative if the battery is installed incorrectly. A power "On-Off" switch is provided.

A large knob is provided for zero adjustment prior to applying any load. This zero adjustment should be checked prior to each tow, but generally will require infrequent adjustment.

A small knob is provided for the Red light/audio setting. When set, the red light and buzzer will give a continuous glow/hum over a 20 to 40 pound load range (usually set about 120 to 160 pounds). As the load exceeds the upper setting, the light will flash and the buzzer will give a broken (pulsing) signal, indicating that the load is exceeding the desired range, and is approaching the weak link breakage point in the tow line.

The unit is calibrated 0-250 pounds so that accurate weak-link testing may be carried out with the unit.

NOTE: LOADS EXCEEDING 400 POUNDS MAY DAMAGE THE LOAD SENSOR. ALWAYS CEASE WEAK LINK TESTING IF THE UNIT INDICATES THAT THE LOAD IS EXCEEDING 250 POUNDS. If it is necessary to use the unit to measure loads in excess of 250 pounds, a suitable pully system should be used so that the load sensor does not have to take loads greater than 250 pounds.

The load sensor has a 10mm long by 6 mm diameter loop at each end, to take connections to the tow rope and tow vehicle via suitable shackles, swivels, bolts, etc. as desired. It is not advisable to twist or bend the load sensor, although some minor distortions will not effect its accuracy. Care has been taken in the design to ensure that the load sensor and circuitry have maximum temperature compensation.
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1983/12-08

CHIPPEWA FALLS SKYTING SEMINAR

Dear Donnell,

Bill just told me he has written his own account of the Oct. Skyting weekend in Wisc., in more detail, no doubt. (Ed: See letter below.) But, since this is my 3rd & final draft & it's taken me THIS long, I'm not quitting now!

13 pilots, our van & trailer-mounted winch with 4000 ft of rope, on Gerry Uchytil's house in Chippewa Falls, Wisc., on Oct. 22 & 23 for a Skyting Happening.

It proved to be a good weekend in which a lot of learning went on but a lot of flying didn't. Bill and I figured that was OK, though, because the key to future flying involving 13 pilots and one tow vehicle is co-ordination and knowledge.

During the chilly, cloudy Sat. & the warmer partly-cloudy Sun., 3 pilots chose not to fly but to check-out the equipment & observe the procedures. Out of the 10 who did fly, there were approximately 20 flights.

The longest flight was on Sun., by Gerry, who got up to 2000 ft. on all of the winch rope, & worked a couple of thermals to maintain.

There were a couple of bad judgement launches (slight downwind) toward knock-down time on Sunday, which were discussed upon landing.

Doug Johnson took 1st place in the weak-link breakage & the "frog-jumping look alike contest," 'til he found out that just because Bill's weaklink string & his looked the same, it didn't mean they were the same. A cotton-nylon strand combo just doesn't do the intended job.

On a long check before one of my flights, I was caught not hooked in. Doug wasn't as fortunate. With no hang check, a not-hooked-in-launch proceeded - his (Bill's) communication helmet being ripped off followed by his 2-3-ring release system partially releasing but wrapping around something (downtubes or wires?). This left Doug hang-running by his wrist release cord looking as if he were hailing a low-flying glider. The glider was flying true until a free-wheel by an amazed winch crew & a gradual right turn brought the kite down dragging Doug a few feet in the process.

The kite wasn't damaged & Doug got up shaken but unscathed with nothing to show but some dirt GROUND into the knees of his lovely brand-new Levi's!! Now that's pain!

The whole incident prompted a new pre-launch communication procedure between the pilot and tow crew. The driver is now responsible for asking "Are you hooked in?", "Do you have the release line?", etc., if the pilot forgets to volunteer that information before each flight. (Ed: To prevent "hooked-out" launches, we follow the rule - "Never attach the body release to the pilot until AFTER he is hooked into the glider. If he unhooks from the glider, then unhook the body release.")

I thought the question, "Are you wearing brand-new jeans?" imperative, but my goodness, people can be mean!?

One of Gerry's discovered launch sites was super with the other being a fair alternative.

On the N. wind Sat., we flew the alternate 1.8 mile curvey, bumpy, puddley N-S road.

Our prayer were answered, however, on Sunday with a 5-8 mph E. wind enabling us to fly the 2 mile long straight, flat E-W road.

Along both road sides were various corn field LZ's. But, STAY OUT OF THE ALFALFA FIELDS or we would ruin all of Gerry's careful public relations work with the local farmer. We all behaved!

Bill was kept quite busy making new weak links, inspecting bridles, checking & altering release cords, helping here & advising there. He's sure a good guy to have around a Skyting operation (or even around the house, for that matter).

As the sun set slowly in the West, enthusiastic plans were made for a Skyting Fly-In, sometime in the Spring. Perhaps, by then, Gary S. will have his home-made winch operational, to his satisfaction.

Imagine - a 2 mile long road, surrounded by black dirt fields, 10+ gliders set up, 2 winch-equipped tow vehicles, an Ease wind, a sunny May day -

Terry Cummings
Hoyt Lakes, MN
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1983/12-09

Dear Donnell,

At the Chippewa Falls, Wisc. Skyting Seminar, 10-22-83, we tested the latest test bridle. The auto-release (top & bottom three-ring) with a manual keel release. It worked flawlessly for my two flights, on Sat., but winching through the corn field, after the second flight, destroyed the bridle. For Terry's three flights, she used a bridle that stays with the glider and has the three-ring release between bridle and tow line. This is a very safe and the simplest of bridles. It's bad point is the need to gather up the slack after releasing so as not to present a tripping or snagging hazzard at the L.Z.

I now use a 3/8 inch polypro bridle so that eliminates the need for a leader. I put the weak link next to the bridle. When the 250 pound weak link broke the 3/8 inch bridle did not stretch enough to snap back at me. In the winter, on frozen lakes and smooth fields, I intend to drop the bridle from the glider. I am going to use your original bridle idea but with three-ring releases in place of the horse releases. The top auto-release will be attached out in front of the flying wires, by means of an extension rope, from the keel and heart bolt. The body release is activated by a release cord that is run through a plastic hose and attached to my main support strap on the left side of my harness. The hose enables me to easily get a hold of it with gloves on.

Doug Johnson got the "Frog Award". His bridle stretched, which activated his auto-release too soon. (NOTE: Everyone should use a bridle that will never stretch during the towing operation.) Buck McMinn and I followed Doug down the road for four long hops, that never got higher than 30 ft. Each flight we adjusted the release cord longer. (But not TOO long!) The fifth attempt, Doug didn't hook in and what happened next is unbelievable. Doug radioed the van to go. The glider lifted off, tearing the downtubes out of his grasp and the helmet off of his head. (The mic. and headphone cord running from the back of the helmet to the C.B. (at the top of the A frame) caused this.) I'm glad the radio helmet didn't lynch Doug on the spot! Something I never considered until now. By the way, the chin strap was snuggley fastened! Doug was then being pulled down the road about 30 feet or more by the wrist release cord. All the while the glider kept its wings level about 10 ft above the road. 1200 ft away, the tow vehicle crew was trying to determine what was looking different about this launch. It had been pre-arranged that a 15 second lapse in voice communication from the pilot would put the brakes on the tow vehicle. Before that time had passed, Gerry free-wheeled the winch, as Dan O'Hara hit the brakes. All at the same time, the bridle finally became untangled on whatever and released - glider and Doug unhurt. Buck, with camera in hand, was so mortified that he never got in on film.

I couldn't believe that the release line was dragging Doug and not releasing him. Doug's body release may have wrapped around the base tube, when it came off his body. - We just don't know why it didn't nose over or why the glider didn't yaw right immediately. (The release cord came down the right down tube inside a sleeve.) Doug did get two good flights after this, but on a bridle that stays with the glider.

A real learning experience otherwise. The next should yield more flying time and less logistics. Everyone that wanted to fly got to. There were only 20 flights aprox. The next weekend at home I had a fun, short thermal flight. Release at 800 ft on a 1,200 ft line. Caught a weak one at 600 ft and took it up to 1,640 ft when I had to leave it to make it back to the field. I wish now I had stayed with it, but I hadn't made plans for a cross-country.

I have been talking to a hydraulics company. They are going to make a pressure device specifically for skyting. They are going to make up a test model for me. If it turns out that they make a good pressure device, I would like to find a hang gliding dealer, or salesman, that would be willing to handle a bulk order of - say 100+ units. The company understands that the price must be below $150.00 each. (Much lower, I hope.) I don't care to bother with export red tape and the like. So if this company can make an affordable pressure device, for skyting, I would hope we could find a salesperson, through your publication, that would handle this.

Bill Cumming
Hoyt Lakes, MN

((Cummings))
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1983/12-10

FLORIDA FEEDBACK

Dear Donnell,

I would like to say that once again (it happens in all areas) an innovation and new idea has sprung from outside the established community. Your tow system has opened everyone's eyes within the hang gliding community as to how easy it is to become lulled into a certain closed minded way of thinking - contratulations!

I have towed fifteen times to date on the skyting system with great success. We are using a homemade bridle similar to Gary Whitman's with a three ring release which stays with the glider. This method alleviates the problem of pulling the bridle out of the bushes after release. We put the weak link between the release and 1000 feet of 1/8 inch hollow braid poly. The prestretched nature of the 1/4 inch rope used for the bridle eliminates any problem of a snap back. Another 1000 feet of 3/16 inch poly is then added to complete the 2000 feet of line. I first used Whitman's garage scale device but had problems with its accuracy. I have since made up a hydraulic cylinder which works extremely will. The cylinder has a 1 1/16 inch bore with a four inch stroke and reads pressure directly on the PSI gauge.

The highest flight we have made has been to 1150 feet AGL in a smooth 500 fpm climb. To get this smooth climb, the driver first watches the speedometer and accelerates up to what would be an equivalent airspeed of 22 mph. (Example: 12 mph ground speed in a 10 mph headwind.) This seems to work well for my 155 lb weight in a 165 Comet. After the pilot is airborne, the driver then uses the PSI gauge to regulate the tension. The gauge is very accurate but there is a definite lag because of the line stretch which the driver must become familiar with. The biggest initial problem we have had is the natural tendency for the pilot to pull in too much on takeoff. It seems that the fear of the bridle pulling up on the base tube frightens people into pulling in: but all this accomplishes is to confuse the driver into speeding up. If the tension on takeoff is correct, this bridle effect is not a problem. At first I had trouble with adverse yaw but have since found that by "snapping" the bar left or right to correct and immediately returning to center a straight tow can be achieved. I have towed up on thermaling days and by keeping control input to a minimum had no problems.

I was excited to learn that Butch Pritchett and Denis Cummings have both had impressive thermaling flights from the system. I hope to be writing soon about similar flights here in Florida - we've been looking up at these cumulus clouds far too long.

Thanks for your information and hard work. You have given this sport a real boost.

David Dodge
Ocean Ridge, FL
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1983/12-11

SKYTING BLITZ

Dear Donnell,

The Donnell Hewett towing system has recently blitzed the Hang Gliding fraternity here in Australia. It is particularly applicable in Western Australia, where I live, as we have very little hills - in fact, our premier Coon Country site is only 900 ft AGL and is 4 hours from where I live.

This system will change the sport drastically.

A.A. Jones
Allanson via Collie
W. Australia
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1984/01
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SKYTING NO.21
JAN. 1984
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REPORT FROM ONTARIO
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1984/01-01

Dear Donnell,

Sorry for not contributing to the Skyting Newsletter earlier. I have put pen to paper often but with each new newsletter it seemed that any questions I had of inovations I made in the development of skyting here were contained in your newsletter. My personal experience since first skyting in Feb. of this year has been more than 30 flights. I had no previous towing experience so I had none of the fears. By the 5th to 7th flights of the 1st day, I was towing up to 700 ft on my single surface Hi-Way Super Scorpion. This was all behind a snowmobile on frozen Lake Simcoe. We are planning Skyting seminars and instruction for next year.

Skyting is catching on in Southern Ontario. We have had successful flights towing behind my 1/2 ton pickup, a snowmobile, and a powered, low-tension winch.

LOW MASS BRIDLE USING THIMBLES

I designed the skyting bridle I am now using after reading the 1st and 2nd Skyting newsletters. I use 1/4 inch braided polypropylene rope for both the bridle and the main tow rope. I like to refer to my bridle as a low mass bridle. I do not use heavy steel rings for my pulley system, instead, I employ 5/16 inch steel rope thimbles. This is easily fastened to the end of the rope back into the center itself and fitting the thimble into the loop at the end. To prevent the thimble from coming loose. I whip the rope tight at the base of the thimble. The resultant bridle is light in weight and the radius of curvature of the pulley system greater than that of a four inch diameter steel ring. Care must be taken to file smooth the sharp edges of the thimble before it is installed. I have found the bridle to operate smoothly during all stages of towing and due to its low mass, the weak link can be located close to the bridle with only a 3 ft leader.

In my skyting set-up, I use two three-ring releases that remain with the pilot and glider. I auto release the top line only. This gives me the option of reaching up and releasing it so that a higher tow can be attained by towing only from the body.

ELIMINATING WEAK LINK CAUSES PROBLEMS

There are at least three groups in Southern Ontario actively towing or getting ready to tow. All are using the skyting system. We have had problems only when one or more of the skyting criteria were not met. One near tragic incident occurred when two pilots, new to skyting eliminated the weak link while towing behind a snow mobile. The weak link was breaking too often so they omitted it. On one flight to 800 ft, the pilot released the body latch only to find that the auto-release line had broken. The driver was unaware of any problems as no observer was used. The glider now being towed only by the keel ring, located 18 inches ahead of the c.g. began a radical and speedy descent. The pilot had his hands fully occupied trying to hold on and control the glider. He could not reach up and release the keel latch. At about 200 feet AGL, the tow angle had more of a horizontal than vertical force component and the pilot was able to gain control of the glider and reach up to release from tow.

This incident underlies the serious consequences that can and will result when the skyting criteria are not followed. It may seem only that one criteria was broken, that being the lack of a weak link, but on examination it becomes evident that more are involved. Besides failing to employ a weak link in the system, they also did not carefully examine their bridle to see that all lines were free and operational. No observer was used who could have released the glider when the irregular flight behavior was noticed.

We can be thankful that modern gliders are strong enough to withstand our mistakes. The glider in question was a Delta Wing X-180.

To end on a more optimistic note, this same pilot has flown 15 miles cross-country after releasing into a thermal at 300 feet and riding it up to 5000 ft.

Frank Fruhwirth
Richmond Hill
Ontario, CANADA
*
1984/01-02

A VISIT TO KINGSVILLE

Dear Donnell,

I wish to express thanks for making it possible for me to fly and for making our visit to Texas truly memorable. It will take us some tome to absorb all we learned.

BACKGROUND

It has been my dear wish to fly since childhood. However, I contented myself with model aircraft for many years. It was not until after college in 1978 that Rona and I attended a four day hang gliding beginers course on the cold damp hills of the Pennines. We progressed will completing many straight flights from heights of 150 ft.

Two years later, this time in South Wales, I attended another course, achieving similar 150 ft flights. At this time I was having serious doubts for my continued flying, it appeared to require large sacrifices of business time, money, and patients for the British weather.

In 1982 Rona and I set out on a trip to Australia with thoughts of sun, dry air, and flying. I was fortunate in locating myself temporarily with a reputable hang glider manufacturer where I felt assured of lots of flying. However, one year later reviewing the situation, I had achieved a hang II rating with no more than 6 minutes of flying - and still it was difficult to get to the sites.

Realising that I was not alone in my quest for air time, I spent time thinking of improvements. The teaching was excellent under the present circumstances - accessibility for the "would be pilot" seemed the biggest problem. My imagination was captured while reading an article on the Donnell Hewett Bridle System of Skyting in Hang Gliding magazine. I wrote for information which Donnell promptly returned. The back issues of Skyting took some absorbing, however, the more I read the more I felt confident that this man had done a lot of homework and was generous enough to share his findings.

Fortunately for us, it was possible to arrange a visit to Texas. I speculated on a long chat about the system, hoping to observe it in action, coupled a vague idea of even trying a little more myself. We were welcomed with enthusiasm on our eventual arrival in early November 1983. Donnell quickly arranged a schedule to get me airborne (planned around his very busy life style).

START OVER

The Rogallo and Gemini were very unfamiliar after the English and Australian gliders I had previously known. Ground handling was exhaustive work but necessary as one spends more time at launch with skyting than with conventioal ridge soaring. I progressed gradually through "man tows" to short hops, getting familiar with the necessary control. Over input seems to be a common mistake. An attitude of "relaxed alertness" is a difficult mode to adopt. Slow progression avoided all fears and inherent dangers in the quantum leap phenomena Donnell talks so much about.

Skyting for me feels real from takeoff to landing. This may sound strange but in my opinion, compared to previous experiences I was at last flying ! This may have something to do with the flight durations which averaged 2 1/2 minutes (that's one minute tow and over a minute free flights). We were towing on 500 ft of line to heights of 400 feet converting to prone flying in circles down or back to takeoff - all this in 6 half-day sessions. The transition from towing to free flight is a novel feeling but due to the gradual advancement program it was mastered easily.

QUIZES

I feel it is very necessary to pose questions to the novice skyting pilot to serve as reminders of dangers and possibilities of malfunction or entanglement during flights. Glider control being fundamental in any situation, followed by manual disentanglement or what ever is necessary to put right the situation. I failed to answer a question on the corrective proceedure for being gusted 90 degrees cross and maxing out at release time.

The importance of wheels and gloves I learned the hard way - escaping with scraped hands and a torn flying suit due to some "flast tarmac" landings.

And many thanks to Helen, Rona, Ed, and Kathy, who made it poissible for Donnell and I to enjoy many flights over the flat Texas countryside. During which time we were able to make minor improvements to premature release systems which can be tiring when alone at takeoff. Donnell modified the bridle to incorporate a manual body release, a neater route for the keel release cord, and incorporation of a third safety release away from the control base bar.

Once again, Donnell, thanks for all your hospitality and flying time. I hope we helped a little with the painting of your house. We look forward to meeting again in the future.

Tony & Rona Webb
England
*
1984/01-03

P.S.

Dear Donnell,

I feel it is necessary to write a follow-up to the previous letter. Here are a few notes about things that interest me or which pose comments or questions:

1. We had a slight problem connecting the bridle to a conventional cocoon type harness. Our configuration is shown below, does anybody have comments upon improving this, or possible disadvantages you may have discovered about using this configuration?
+
((Platform launch configuration depiction.))
+
2. Donnell, we should have spent more time familiarizing you with the cocoon. This probably would have prevented you from falling on your first takeoff attempt. Perhaps future attempts should be preceeded with ground crew assistance in all prone, upright, and running attitudes.

3. We found wheels and gloves necessary equipment (already covered). Our airspeed indicator was also useful for control in takeoff and tow-up (as well as per usual in free-flight).

4. The bridle release cracked (figuratively speaking) some knuckles on the way past the base bar when released at maxing out. This obviously could be avoided by tracking left or right and releasing a little before maxing out. (If you want more height, lengthen the towline.)

5. A better cross wind takeoff technique is needed for the Gemini. Donnell was experimenting with windward wing lowered, pointing the nose of the glider to windward until run begins, when the glider straightens to pull direction on lift-off and begins to track to the leeward side of the vehicle. Also it helps to begin with vehicle pulling and as diagonally as possible to wind on runways.

6. Using the kid's kite to check wind speed, direction, and gradient was quite effective and should be mentioned.

7. It is the small incidents that are important. In cross-wind takeoffs it is difficult not to let a wing drop and result in a ground loop. Donnell had a little tube bending to do after such an incident. (Ed: I tried a cross wind takeoff wearing a cocoon harness for the first time, with a new bridle connection configuration, and with a new method of holding the glider before takeoff. A bunch of "little" things mounted up to a lot in this case. Minor damage to the ego. You'd think by know my ego would be invulnerable, wouldn't you? But friends just kept reminding me of these unfortunate incidences. Nobody ever reminds me of my GOOD flights! According to the SKYTING press, I have more accidents than good flights. In reality, the situation is just the opposite.) Maybe a little more detailed analysis of the small things may divulge some bigger secrets.

Tony Webb
England
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SINGLE RELEASE IS SAFER
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1984/01-04

Dear Donnell,

As we have been using a single release at the apex of the bridle since April of '83 and not used a two release system, I don't have hands on experience of the double release. But the stories that I have read in Skyting and Whole Air are nightmares. It appears to me that you would try a single release. And then see the advantage being less dangerous. And start promoting the single release.

This is a bold statement and I hope you will print it. But the double release is too complicated to adapt and too dangerous to fly with. I also understand that some people have given the Go Go Go and not been hooked to the glider or pilot with the bridle geometry. This would not be a problem with a single release because the rig would move out away from the glider's pilot and release at the end of the release line or release cable.

SHORT TOWLINE IS DANGEROUS

I also read of people starting on a short line - say 200 to 300 ft. I also think that this is dangerous. You should use at least 700 ft or 1000 ft of line to get the stretch of the line to your advantage. If you don't want to go that high at first, then notify the driver and release at a lower height.

TOWING RIGID WINGS

In SKYTING #18 Frank Smallman asked about rigid wings. We have been towing a Fledge since April of '83. Miller Stroud who flys the Fledge says that he prefers to use a Yarnell Bridle & Release with our system. A Fledge does not turn by weight shift and the tow bridle (skyting) does not help in control. Miller also said that the initial climb was a lot steeper with the skyting bridle than with a properly adjusted Yarnell system. I believe this to be true only to the Fledge.

SPRING TOWING GET-TOGETHER

It is cold here now -3 F to -17 F wind chill and the flying has stopped till warmer temperatures. This spring I would be glad to have a towing get together and exchange ideas with everyone. Anyone interested should contact me and maybe we can set something up. Maybe we could get "Hang Gliding" and "Whole Air" to be there also.

Butch Pritchett
Box 299
Finley, TN 38030
901/285/9490
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1984/01-05

Dear Butch,

The evidence is growing in support of your position favoring the single release bridle over the double release. Since I have never flown with the single release system, I cannot actually promote it. There are still a few questions I have. Primarily they deal with how the release is activated in an emergency. If you use a pull line to trip a two- or three-ring release, what keeps this line from getting slack (either on takeoff or when prone) and requiring the pilot to take up this slack before being able to release. I also wonder how you release from a slack towline without having to pull the release system up to the pilot's hands. So far no one has written any detailed description of their single release system. (The most detailed description I have seen is Gary Whitman's in a back issue of Hang Gliding.) You would do us a service if you would write up an article describing yur system in detail so that others could copy it without undue experimentation. This is particularly true if you are really satisfied with your system. If not quite satisfied, state where and why and perhaps someone else can help make it even better.

Donnell
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1984/01-06

MINISOTA WINTER SKYTING

Dear Donnell,

We started our snowmachine towing 12-4-83. The ice was 4" to 6" thick with 4" of snow cover.

EXTENDED KEEL

I test flew a bridle that I feel is one of the two safest options to date. This one is the extended keel release that lets the upper release release out in front of the glider's wires and tubes. It is activated by the auto-release cord. It is patterned after your original bridle only I use tow 3-ring releases in place of the two horse releases. The other bridle I like is the one that stays with the glider and has one release out at the tow line and bridle junction.

The bridle that has the auto bottom release only with the manual top release has given pilots a bad nose down problem when the bottom release was accidently tripped first. This situation also could put a sudden jerk on the keel tube to the tune of 250 lbs in my case. Sixteen inches ahead of the heart bolt on the keel tube isn't a good place to to put that kind of sudden load. So an auto release line to the top release sounds like a very good idea. A good safety back up might be to try and spread the load out along the keel tube instead of one small attachment point.

The bridle that releases at the keel tube, without benefit of an extension rope, may snag a flying wire on the way by. This also has been known to snag a pilot and base tube.

TETHERED SKYTING

On Monday 1-2-84 Don Ray, from Auroa ((Aurora)) MN, Jerry Danielson and Gene Stone, from Grand Rapids MN, Terry and I went to Swan Lake 14 miles west of Hibbing MN. The wind at take off, on the ice, was 4 mph SSW. At 1000 ft it was 25 mph, later slowly increasing to 35 mph out of the WSW. We used 1800 ft of line. Gene Stone started with two flights, 7 min apiece. Both flights Gene had me slow to a complete stop then he topped off with the snowmachine stopped. On his third flight, I pulled him to 1000 ft and stopped. He climbed to 1500 ft on his own and tether-flew for 22 min.

My wife, Terry, had a tethered flight of 38 min at 1520 ft - the longest of the day. Don Ray had 2 flights tethered, on for 15 min and the other for 22 min. Jerry Danielson went to 1500 ft when the weak link broke. The wind up top was now 35 mph.

I took the last flight of the day. At one point Gene turned the snowmachine around and ran toward me when I signaled slow. When I got down to 1000 ft I had him inch to the far shore with the bar stuffed. I wanted the whole mile of lake so I wouldn't be blown past the down-wind shore. Gene stopped on the west shore line and I let out on the bar. I climbed to 1600 ft when the weak link broke. I flew at minimum sink and drifted backwards for a mile to the L.Z.

The whole day long the ground wind never exceeded 5 mph. At 400 ft and 1000 ft there was only the slightest hint of turbulence. In the six years that I have been flying there have only been five times that I remember flying this much of a gradient with no turbulence. What a day!

The next time we tether on a frozen lake we are taking the ice auger and an inch and a half diameter wooden dowel, so that we can anchor the pilot and try and get the next pilot up besides the first.

Bill Cummings
Hoyt Lakes, MN
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QUESTIONS AND ANSWERS ON WATER TOWING
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1984/01-07

Dear Donnell,

I'd like to clarify a few things which caused you to have some questions about my last letter. (SKYTING #20)

REEL

First, we have no real problems towing on a long line using the High Perspective Reel. The reel does not have a mechanical constant tension device. Line tension is produced by an operator pulling on a lever which operates a drum brake. The pull required to keep a constant tension on the line changes somewhat depending on the momentum of the drum and how hot the brake is. Though gaining a feel for the necessary pull on the lever at different times during the tow is not difficult, feedback from the pilot via leg signals verifies everything is going well, too slow, or too fast. During the tow to 2900 ft, I lost "ALL CONTACT" with Dan and therefore tended to apply tension conservatively. This was not a problem it just resulted in less altitude. Though the reel is designed so that the maximum tension one can achieve does not overpower the glider (break it up), you can get enough tension to give the pilot a very hot ride.

STATIC LINE

Second, we use two towing set ups. A static line set up for beginners and a reel set up for those pilots who have the deep water take off and response of the glider on tow under control. The minor mishaps and skytouts we've encountered have occurred during a pilot's learning stage which takes place on the static set up.

The static line set up employs a quick release in the boat, 150 ft of low stretch line, and a bridle with a release at its apex and release lever on the base tube. Though a longer static line would be desirable (we used to use 255 ft) the short line aids in a more efficient deep water start. The start is a whole new situation and even veteran pilots have failed to use their release in time when they have needed it. The boat release also gives the boat crew control in case of trouble. Once the pilot is in the air on the static line, we keep him about 25-30 degrees, under mild tension as he becomes comfortable with controling the glider under tow. The static line set up does not allow for a weak link because of the take off forces.

The reel set up uses a continuous line and therefore does not employ a quick release in the boat. A pilot is not put on the reel until he has demonstrated good control over take off and towed flight. A weak link is used with the reel. The weak link is protected from take off forces by placing it behind the 150 ft take off leader and putting it under a few wraps on the reel.

I hope the above answers your questions.

QUESTIONS

I have a couple of questions for you. One, it would seem to me that as the glider gains altitude (say above 2,000 ft) that the weight and drag caused by the rope start to become significant. This is adding to the mass of the glider-pilot system? It would, therefore, seem that to achieve the same rate of climb that you had at a lower altitude, you would have to increase your tow line tension?

Two: At high tow angles the upper and lower bridle lines are pulling fairly straight down. This also occurs at moderate (45/50 degree) angles on a long line high altitude tow. I don't find the upper line much of a problem (getting in my way) - I just yaw my body out of its way. What I do find tiring is the negative bar pressure experienced when pushing out to increase my climb rate. Would towing from the body line only at these high angles (rope) improve our climb rate - or at least allow for control with less negative bar pressure?

We are developing a dual release system so that we can release at the upper line and at the apex of the bridle using two independent levers on the control bar. I don't expect a drastic handling difference towing from the body line only when the tow line is pulling almost straight down. What feedback do you have on this point?

COMMUNICATION

I'd be glad to put together an article describing our equipment and techniques. It may take some time, communication using the written word does not come easy for me - it is a slow, time consuming process.

I wish we did not live worlds apart. I feel more direct and frequent communication - especially during the towing season - would be very beneficial. We could get you up over water - maybe save some bones - and have fun getting high!

We do have a good friend that lives in Houston and last Easter I tried to get hold of you while we were visiting. No answer for 3 straight days. We took a trip to Galveston - and Kingsville is just a hop, skip, and a jump from there. - But no Donnell. I was disappointed to have missed meeting you. Oh well, maybe sometime in the future.

Don Boardman III
Rome, NY
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1984/01-08

Dear Don,

Thanks for writing and for clarifying certain misconceptions I had gained from your last letter. Let me make a few suggestions which you can take or leave.

Since your winch tension is manually operated you could probably better provide constant tension if you developed a tension meter on the line. Your winch operator could adjust his brake pressure according to the towline tension, much as a driver adjusts his adjusts his speed in non-winch towing. I can think of several possible arrangements to accomplish this feat:
+
Standard Tension Gauge

Spring or Hydraulic Gauge
Pulley
+
Automatic Regulator

Adjustable Tension
Pulley on Break Leaver
+
Winch on roller track

Spring
+
You can use a weak link on a static line system if you use two releases. Once the pilot is airborne, and the towline tension slacks off slightly, release the main towline but hold on to the weak link. When the glider needs to be released from the boat, release the weak link:
+
Take off Situation

First Release
Second Release
+
Towing situation

First Release
Second Release
Cord
Weak Link
Towline
+
TOWLINE DRAG

Now in answer to your questions: yes, the weight and drag caused by a long towline can become significant. But from the glider's point of view there is no difference. (I.e. there is no mass added to the glider-pilot center of mass system.) The towline tension is greater than normal because of weight and drag of the line are added to that required just to fly the glider. Since the tension will be greater at the top of the towline, the weak link should be placed at the top.

The towline will "sag" more than normal, so the direction of the towline force will be different at the bottom than at the top. At the bottom the towline will be almost horizontal, while at the top it will be almost vertical. Since it is the forward pull on the glider-pilot that provides the thrust to keep the glider flying and climbing, and since this forward component is small at large tow "angles", then the longer the towline, the harder it is to supply the thrust needed. The boat cannot simply drive faster to produce greater tension because by the time that tension is translated up the towline it becomes greater and pulls down instead of forward, breaking the weak link.

In practice, this means that one will have to fly closer to the weak link break point to get high tow angles on a long rope - there is a limit (or point of deminishing returns) in using a long heavy rope. You know better than I whether or not you are approaching the limit with your present set-up. If you are, you may want to use a thin cable instead of the larger diameter towline - you want the least drag you can get. I don't know if I've told you anything you don't already know, but it's been fun trying. One of these days, I would like to tow on a long line and experience some of these phenomena.

BODY TOWING

Now concerning your question about body towing. Yes, after the tow angle gets large it is a simple matter to tow from the body. There are two cautions you should be aware of: (1) do not body tow at the takeoff or at low tow angles. The forward thrust of up to 1 g below the center of mass of the glider pilot system can cause a pitch-up tendency which the pilot may not be able to overcome. (See SKYTING #19 where a pilot was killed doing this.) (2) Do not change from CM towing to body towing while under extreme tension. When the tension on the glider (keel) suddenly goes to zero and that on the pilot suddenly increases, the glider (trimmed for CM towing) suddenly pitches upward. This has produced broken weak links and whip stalls before.

However, when the tow angle is high and the tension is reasonable, there is no danger in body towing. I have done this several times. Control of the glider is about the same, but the "feel" is different. Specifically, the pilot can feel the full load of tension pulling on his body and the shift in the trim of the glider. Personally, I did not care for the new "feel" and, therefore, only flew that way when the keel line was a real nusance at high tow angles.

Another alternative I have tried is to gently release the keel line and hold it in my hand at the center of the control bar. Except for the fact that I had to keep my hand at the center of the control bar, I liked this arrangement better. The pull through the control gar to the glider seemed to leave the glider in the normal trim arrangement. Since the tow force was almost straight down, there was no noticable lockout tendency (as there would have been with a horizontal force on the base tube). Besides, I could slide my hand along the base tube and let the tow force help turn the glider if I wanted to. And finally, if necessary, I could simply turn loose of the line and tow from the body.

COMMUNICATION

There is no real hurry for your article on your system, but I am looking forward to reading it. You do have a good, interesting style of writing.

I, too, wish we did not live so far apart. Frequent and direct communicatioin would be wonderful. I would love to take a high ride over water. But wishing for that which is not is of little value. And since I strongly believe that "everything has advantages and disadvantages", I can find advantages to the situation as it is: Since we have to write down what we say, not only does this require clearer thinking on our part, but others can benifit form our conversations as they are published. Who knows, there may be more TOTAL good with things as they are than with them as we wish!

Next time you plan to be in Texas, let me know in advance and we may well be able to get together. For example, the reason you could not get me on the phone last Easter was that I was in Luling, a town 100 miles closer to Houston than Kingsville.

Donnell
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1984/01-09

FAA CLAMPS DOWN ON ULTRALIGHT TOWING

To: Steve Hawxhurst, President USHGA, and USHGA Board of Directors

I'm writing this letter on behalf of the hang glider towing constituency the FAA's position on hang gliders being towed by powered ultralights. The problem being that AEROTOWING WITH POWERED ULTRALIGHTS IS ILLEGAL. Ultralights are considered "experimental aircraft", and certain modifications must be done in order for them to meet FAA requirements for towing, plus the ultralight pilot has to be signed off for towing.

As I understand it...first the ultralight must be certified as being an experimental aircraft; and secondly it must be modified for the towing certification. These criteria can be met.

However, since hang gliders are presently classified as "ultralights" by the FAA, we need an EXEMPTION under Part 103 which permits an ultralight tow vehicle to tow another "ultralight". Also the exemption should state, "for non-commercial purposes", because present wording in the F.A.R. restricts use of ultralights (i.e. flying them) to "recreational and pleasure purposes only".

This is a bit confusing, but evidently in the eyes of the FAA, ultralight towing would be for purposes OTHER than for recreation and pleasure.

At this time I'd like to recommend that we initiate an Action Item on this topic of ultralight towing, and that anyone on the Board who has had past experience dealing with the FAA and with writing of applications for exemptions (such as the tandem exemption), to follow up on this one. If no one in our ranks is prepared to pursue the issue, Bob Fisher has informed me that he is prepared to do so on behalf of the USHGA. He would be glad to handle the necessary communication and writing on his own, or to give backup support as requested to any other person dealing with the matter.

Fisher states that this matter deserves priority attention: "Europe is moving ahead on ultralight towing while the United States is being left behind". (See article in Wings Magazine about a tested and fully developed ultralight towing system in France.)

Hardy Snyman
Director - Region 11
Secretary, USHGA
Houston, TX

NOTE: I am currently trying to learn more about this matter. If any of you have additional information, please contact me. I do not know that (1) USHGA is not waiting until their February Board meeting to get started on this matter (i.e. efforts are already under way to get ultralight towing legalized in the U.S.), (2) USHGA has been extremely successful in the past in getting similar problems resolved satisfactory (i.e. the tandem flying exemption), (3) USHGA is the only hang glider organization which has a reasonable chance of getting ultralight towing legalized in the U.S., but that (4) USHGA membership has been declining dramatically recently and its financial status is not what it used to be. The conclusion is obvious: USHGA needs your support ! If you are not a member, then join - the greater its membership roll, the more likely the FAA is to listen. If you can assist in the effort, volunteer - the more people actively involved, the better the chances of getting a favorable ruling. If you can afford it, donate money - USHGA's budget has been cut back to the very minimum and money is needed to carry out this campaign. And finally, if you do not like the way USHGA has been run in the past, here is your chance to be heard - if USHGA was ever willing to listen to its membership it is willing now. Tell your regional director that you think towing is important to the future of hang gliding and why!

Donnell
*
*

1984/02
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SKYTING NO.22
FEB. 1984
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1984/02-01

UPDATE ON XC TOW LAUNCHED MEET

(Ed. This letter was received last October, but because I was pitifully slow in answering it, it was not published earlier. Since it contains important information you should be aware of, I am publishing it now.)
*
1984/02-02

Dear Donnell

My name is Betty Moyer ((Pfeiffer)) and I am working with Rich Pfeiffer in setting up the XC tow launch meet scheduled for next summer. Rich indicated that you wanted to be kept informed on our progress.

Last saturday I met with a number of hang glider pilots. Some had towing experience - some did not. The purpose of our meeting was to demonstrate Skyting to two sail plane meet directors in an effort to gain their committment to run our meet.

The day was a fiasco. It started with a trike pilot crashing in an attempt to land near us, and continued with one mechanical breakdown after another. It culminated when one of the potential meet directors, Tripp, decided to try towing. Although Tripp was a top notch hang glider pilot, he did not have recent experience. He has only flown the newer gliders once. At that time most people did not realize his limitations. So there he was, new glider, new system, unfamiliar harness and he was ready to tow.

On tow, Tripp started to overcontrol. The glider yawed but did not seem to bank much. Tripp got scared and turned the glider 180 degrees to the tow truck. He then tried to release. The top release line snagged on the CB mounted on the corner of the control bar and thus there was no tension on the line and it would not release.

When the winch operator saw what happened, he decided to release the winch and allow it to free wheel. The driver turned around and followed the glider so it would not be flipped if the line should become taut.

Fortunately the line did not snag on anything, and Tripp landed safely. Rick Masters got the whole incident on film. As a result Oscar Higgins and Keith Blaylock are working on a radio controlled release to be located at the bridle. This system will be used for first timers.

Although Tripp had a knife on hand to cut the line, he didn't think to use it. Neither did he think to unsnag the line. Nor did the people with the CB's think to call him on the radio.

After that I was sure our chances to use the sail plane meet directors were gone. Fortunately both men are still open minded enough to reconsider their involvement when we have more of the bugs worked out.

In an attempt to work things out we will be gathering all the local towing enthusiast together as often as possible. We would also like to run a Skyting clinic during the week just prior to the meet. At that time we will invite everyone who has a winch to come to El Mirage, exchange ideas, inspect equipment, and help the competitors learn to tow. At the meet each competitor will be required to have his/her own bridle and release system. He/she will also have to demonstrate 5 tows to the safety director using that bridle.

Although we are on a low budget it would be an honor if you could come to California for that week. It will be this July. I am sure your expertise will help to make this First XC Tow Launched Competition as safe and successful as possible.

Betty Moyer
Santa Ana, CA
*
1984/02-03

MORE ON THE STV

Dear Donnell,

So far we've had more than 50 launches using our car-winch system (SKYTING #12) with excellent results. Speed control is superb, because the winch driver can see the pilot's signals (clicking heels to slow down, "pedaling" motion to speed up), and response is instantaneous because the only load on the car's engine is the drag of the glider. A tension gauge isn't needed.

Using this winch, you can tow up in any field smooth enough to get a car out on. If there is enough interest from other readers, I will write a detailed article for the newsletter. (Ed: There is enough interest, so start writing.) Or, interested people can call be at 902-443-1813. (NOTE! We are on Atlantic Standard Time. 10 pm on the West Coast is 3 am here!)

Tom Bushell
Halifax, N.S.
CANADA
*
1984/02-04

TWO NEW BRIDLE DESIGNS

by Mike Lake
Norwich, Norfolk, England

IT'S AMAZING!!

I have been hang gliding for over eight years and towing since 1979, yet this is the first I have heard of your publication and excellent development work (although I am familiar with the system used). I think the reason for this is that I live in a very unfashionable area of England hang glider wise and often things do not seem to filter as far as me. However there is a possible advantage to this in that the development of some of our equipment/methods have found a different path so if I may use some of your pages I will briefly outline the hardware used, which I am sure you will find of interest.

THE WINCH

We have adopted the payout system as we feel this is certainly the most efficient in terms of height gain, number of launches per day, and safety. However, it did not cost us an arm and a leg. The cost of the winch less the line was approximately 75 quid (er sorry 75 pounds or $100) and I am sure that that's not much in dollars either! This was achieved by designing it around as many off the shelf and breakers yard parts as possible. If this sounds rough and ready, do not be deceived due to the engineering skills of the builder Paul Whitley. It is as smart and efficient as any of the 1000 pound ($1300) wonders we have seen. (By the way, this is the first time I have revealed the true cost.) The whole unit is mounted in the back of a small trailer (Do you call them trailers over there?) which is approximately 5x4 feet. Any vehicle with a tow-bar can be used for the power. This complete unit together with 3500 feet of line cost us less than 160 pounds ($200). This is surprisingly less than the total cost of bridle development which I will now describe.

BRIDLES

Many different bridle configurations were tested and the two bridles described here are the ones we use and are the result of much development work.

STEP UP BRIDLE

This is best described as a two step system. As you can see, the "V" configuration is nothing new. However, the trick lies in the way the bottom leg is connected to the harness in such a way that it is shortened as the pilot pushes out into prone. While in the gorilla position, the glider is held at a relatively low angle and for the novice pilot it will not pitch up too much while he is thrashing about looking for his stirrup. It is a single release automatic system and it is particularly easy at take off. Control under tow is good. In free flight a quick release buckle ensures the whole unit is wound up out of the way of the pilot. Incidently, the plastic tube enclosing the top leg is to ensure that nothing can hit the pilot's face (a very real problem). However, these bridles have to be custom made and the harnesses modified. Also, things attached to the glider are always ..... well, messy.

Pilot demand (constant bullying) inspired me to design the next system which I must confess to being rather proud of. So in all modesty I have named it the Lake Bridle.
+
STEP-UP BRIDLE

PLASTIC TUBE
RELEASE
RINGS
STEP DIFFERENCE

T/O
TOP
FREEFLIGHT
LAKEY

TRIGGER
PLASTIC TUBE 1/2"
MALE QUICK BUCKLE
RELEASE
BUNGY
PULLY

LAKE STEP-UP BRIDLE
Copyright 1983
+
LAKE BRIDLE

This is in two parts. At the pilot end there is quite simply a webbing belt with a release mechanism attached, the spreader bar is purely for comfort. The release is operated by a cord attached to the pilot's wrist. No modifications are necessary to the glider or harness. It is totally interchangable, although for what it costs, every tow pilot could (should) have one.

The other end does all the work and is normally enclosed in a padded sleeve. I think you can see from the drawing how it works. This is basically a way to attach the line high-"ish" up the pilot's body but allow it to pass from over to under the base bar as if by magic. (Note: You only need one of these.)

Everything is automatic, and I have found these single point tows to be exceptionally stable with no nasty habits, but one of the biggest virtues is that any pilot can turn up with any suitable glider using any harness and be rigged up for towing in seconds. There is also a VERY IMPORTANT spin off in that because the webbing is attached directly to the pilot, HE CAN FEEL THE TENSION and react accordingly.

COMMENTS

We have made hundreds of launches, several XC's, and any launch under 1400 feet is now considered mediocre. Also a pilot can be airborn every 8 minutes - which is pretty fast.

Both bridles described are very simple to construct, the "Lake Bridle" being suitable for the more experienced pilots as it does not offer any pitch assistance on take off.

They are only designed for low tension towing. I am sure that the tow pilots are asking themselves "what if" and "how do you cope with" questions for which I will be happy to provide the answers (if I can).

I realize this is a very incomplete article, but I will try to follow this up in greater detail bit by bit. I can provide detailed drawing of all the equipment described here although the principles are fairly obvious. If fellow pilots decide to explore some of the ideas then I respectfully remind them to take care and watch some of the deminsions (particularly in the case of the step-up bridle).

This article was produced in rather a hurry with much enthusiasm so please excuse the quality of the drawing, some of which are copies of the original sketches.

Finally, may I express my delight at finding a media to pass on our experiences and hopefully achieve the status it deserves.
+
LAKE BRIDLE
Copyright 1983
T/O
TOP
RELEASE
+
MAIN LINE
BUNGY
WEAKLINK
SWIVEL
PULLY
HANDLE
RELEASE
*
1984/02-05

PNEUMATIC TENSION GAUGE AVAILABLE

Butch Pritchett, Box 299, Finley, Tenn. 38030, 901/285-9490, is manufacturing a pneumatic tension gauge. By using air instead of hydraulic fluid, the gauge avoids some of the problems sometimes associated with the hydraulic tension gauges - problems such as hydrolock and leakage. System includes pneumatic cylinder, line, air filter, and gauge (calibrated). Cost is $150.00 plus shipping. Dealer inquiries invited. Butch also sells poly line in all sizes.
*
1984/02-06

GERMANY UPDATE

Dear Donnell,

We are now putting more emphasis on the Skyting theory. We also changed our initial practical training method in accordance with Skyting.

We use a weak link with a breaking point of 1500 N +/- 10 % (calibrated). (Ed: This is about 337 pounds and seems excessively strong to me.) It is mounted directly behind the drag-chute.

We are also using a 1.8 mm diameter 7x7 mm steel tow wire with a maximum breaking point of 3500 N.

Maximum tow force is derived from a total takeoff weight, minus 10x100 N. For example: My total tow is 110 kilo - 10 x 100 = max. tow force = 1000 N. I prefer 900 N. (Ed: This is about 202 pounds, and is about right for a weak link. Normal tow force should be about half this amount or less.)

We are also using the triple release.

Peter Roth
Neu-Isenburg
Germany
*
TEST PILOT QUALIFICATIONS AND NEGATIVE SEMANTICS
*
1984/02-07

Dear Donnell,

Maybe I overstressed fatigue stress as relates to your accidents: even more important may be your pilot skill level. It is my opinion that test piloting shouldn't be done by beginning, novice, or intermediate rated pilots and done only by advanced pilots using properly designed safety pods if and when such are available.

Also read Eric Fair's excellent advice in his Summary 3, Right Stuff, Hang Gliding, Nov. 1983.

As to disappointment on lack of enthusiasm about safety pod fabrication, I think that "safety", like "supine", has negative semantic word drag; possibly "pilot pods" or "pilot pod fairings with built in safety" would be better.

Before Skyting, I wasn't interested in towing (because of lockouts), but now I think it has more potential for the future than foot launch hang gliding; and pilot protective pods would in many ways be much more practical for a tow launch system than for a foot launch system.

Edwin G. Sward
Worcester, Mass
*
1984/02-08

Dear Edwin,

I agree, only advanced pilots SHOULD act as test pilots. And since others, more qualified than I, have finally begun exploring the characteristics and limits of Skyting, there no longer seems to be a need for my pushing the limits. I hope I have finally gained the patients to refrain from flying at all unless ALL of the conditions are ideal.

You may be right in refraining from using the term "safety" in describing a product yet to be designed and built. Not because the word "safety" has negative connotations but because until pilots actually see through statistics and actual case experiences that pods significantly improve their chances of surviving a crash, many pilots may feel that "restrictive" or even "dangerous" would be a better description. (If pods were not properly designed, they could well be more dangerous than free flight.)

It is also possible that the word "Pod" has negative semantics. Many pilots, when they hear the word "pod", think of the pods introduced in the Owen Valley Classic a few years ago. They were heavy, restrictive, ugly, and otherwise of such character that very few pilots chose to fly them a second time. Perhaps the words "Pilot Protective Flarings", or simply "Protective Flarings" would be better. Then instead of implying a particular design (such as pods) one could picture any number of protective designs, including flexible armor (modified football padding, etc.). Perhaps a light-weight, aerodynamic flight suit with built in padding and support (rigid) where needed would sell?

Donnell
*
1984/02-09

TOWING IS NOT RECOGNIZED IN ISRAEL

Dear Donnell,

As a member of the USHGA, I receive the Hang Gliding Magazine and read the articles about towing. I started to do it after I read the article in May (I received in in July) which was written by Garry and Denise Whitman. Until today I did 30 flights, all of them without any problem.

My problem today is that our association does not recognize the towing at all. The people here are impressed with the towing accidents that happened in the U.S. in the past.

I would like to ask you about more information on the skyting tow system. I wish to explain to our people the system, how it works. I hope they will understand that with your bridle there is no more problem with "lockouts". So there's no reason why pilots in Israel will not enjoy this system.

Heber Itzhak
Nachal Oz
ISRAEL
*
1984/02-10

EXPERIENCE AND SAFETY

My involvement with towing started three years ago using a home made low tension winch and a Yarnell release. Various circumstances limited my participation to 3 low level flights and a single premature release (towed angle of attack much too high - excessive bar pressure - weak link failure - minor cut on face).

On Jan. 2, 1984, I went to observe a group of local experimenters test flying their version of towing, using a technique similar to SKYTING, but with several major discrepancies - no tension gauge, line fastened to truck with horse bridle release, no wheels, no weak link. They did have a safety conscious attitude and the tows I observed seemed to be going well.

When offered the chance to try it, I said, "Yes." Borrowed glider - no experience on design; borrowed cocoon harness - no experience on design (I fly a knee-hanger).

My first launch attempt was aborted. I didn't have my legs in the leg straps. At the time I felt much slower than a review of a video later showed - 3 ft high 5 sec flight.

I tried two more tows to about 300 ft. They went fairly well but I was releasing under tension. My first landing was hindered by the interference of the tow bridle draped over the flying wires. I couldn't flair fully. My second landing was downwind. I figured I'd quit while I was ahead.

I am going to study your material and observe as much as I can before I try again. I will set up my glider and harness with my release, use a tension limiting device, a weak link, and wheels.

I will try to learn from the mistakes of myself and others and above all else I will FLY SAFE.

John Reed Maffeo
Phoenix, AZ
*
1984/02-11

SINGLE RELEASE

After two months that I didn't skyte because of weather and other reasons, I launched again last week. New driver, new road (different wind direction this season of the year). I used my gear as before in 30 other nice flights. The car started, I did a few steps, and more, and more... the driver didn't accelerate enough (it happens all the time with new drivers, and I had many of them) and didn't drive in the speed that he should. So I couldn't take off. Then I lost control on the glider, it turned, nosed in, weak link (70 kg) broke, and one down tube was bent.

I didn't like this situation, mostly because of two reasons: First, what happened was out of my control. Second, same thing like what happened to me in the past, the first time that I used skyting. If it happened to me now, even because of the new driver, then there is a possibility of it happening again in the future.

During the launch, I kept running and the glider banked. The bridle caused it by lifting one side of the control bar. I couldn't use the release line because it was tied to the control bar and I couldn't reach it.

At home I decided to make something to prevent a situation like it in the future:

1. When I have a new driver or something else for the first time, I let the bridle go through the A frame (not under). It makes the take off much easier. The bridle then cannot lift any side of the bar and change the balance of the glider.

2. I connect the release line to the top of the down tube (see figure). This lets me use the line when I hold the glider or run with it. I set the release line so it will work automatically in any situation that the angle between rope and glider becomes smaller than what I decide. I tie the line when someone holds the leader and the glider-rope angle is about 5 degrees.

I made four flights with the new line release and find it works well and is very comfortable to use.

I think that it is much safer to release only one point. I developed the release by myself. Here I give you the design of it so other pilots who can make it. The one I made was tested to work in 130 kg of tension.

Heber Itzhak
Mahal Oz
ISRAEL
+
illustrations
*
1984/02-12

KEEP TOWLINE OVER BASE TUBE

I would like to mention a problem with towline position. I would recommend never putting the bottom line under the base tube. You can get away with it if the glider is not excessively pitch sensitive, but with a double surface high aspect ratio (e.g. Streak) glider it will put the glider in a mush stall in the first few steps and gliders with excessive lag time cannot recover from even a slight turn in time to avoid a crash. I bring this up because it happened to me.

We have experimented with the harness connection closer to the shoulder straps and this works fine. It also keeps the line away from the base tube at high tow line angles.

Bill Misigscek
Missouri City, TX

((Misiaszek))
*
1984/02-13

TANDEM TOWING, ANYONE?

Mack ((Mark)) Mulholland called me recently and wants to know if anybody out there knows of anyone who is doing tandem towing. He is convinced that one of the safest ways to teach hang gliding (including hang glider towing) is to meet the USHGA and FAA requirements for tandem towing and let the student gain experience under the careful supervision of a highly qualified instructor hanging right there below him. Tandem towing also provides the possibility of giving a prospective pilot a realistic taste of what hang gliding is all about without requiring him to go through the full training program. In this way he can more easily determine whether or not he feels learning to hang glide is worth the time, effort, and money. And if he does decide to become serious about hang gliding, it helps provide him with the motivation he will need to get through the extensive training program.

Mack doesn't want to rediscover other people's mistakes, so if you know of anyone who has tandem towed on a center of mass system, please send me their names, addresses, and/or phone numbers. If you have tandem skyted, yourself, please write up a short description of your experiences with us.

Donnell
*
1984/02-14

AND WE USE A WEAKLINK TO PREVENT STRUCTURAL FAILURE.... BUT SO FAR THE OLD CAR HAS HELD TOGETHER WELL!
CLUNK!
BANG
POW
Lakey
*
*

1984/03
*
SKYTING NO.23
MAR. 1984
*
1984/03-01

THREADED BRIDLES

This issue of SKYTING contains three examples of what I would call the "threaded bridle" design. The concept is beautiful and simple: Instead of the complicated mess frequently associated with skyting bridles, simply thread the bridle rope through the body ring, back through the apex ring, and then attach it to the keel. All you have to do to release is to release the line from the keel and it will automatically unthread itself and fall away, leaving nothing on the glider but the keel latch.

This idea is so simple and straightforward that even I thought of it way back in the beginning stages of skyting. But to be honest, I never had the nerve to try it! "Sure," I said, "it will work MOST of the time, but just imagine what happens (1) when you release under high tension and get popped with the end of the rope as it slaps against your body (face, arm, leg, belly, or groin) like the end of a whip, or (2) when the flopping free end wraps around itself into a knot which cannot possibly be unjammed in time to release the flying glider from the towline. Since Murphy's Law is inescapable, what are you going to do WHEN, and not IF, one of these things "goes wrong"?

Well, it seems that others have tried the idea and found it to work quite well. Perhaps my original fears were unfounded. Or perhaps these inovators have found ways to overcome the problems I anticipated. Or perhaps Murphy's Law has not yet had sufficient time in which to act. I, for one, sincerely hope that the threaded bridle design(s) prove out. It would certainly simplify center of mass towing.

It is interesting that all three descriptions of practical threaded bridle designs were received by me in a time span of less than one month. Perhaps this in an example of "When the time is right, an idea will come to fruition." Here's hoping the "time is right" for the threaded bridle concept.

Donnell
*
1984/03-02

MORE COMMENTS ON SKYTING (CENTER OF MASS BRIDLE TOWING)

by Warren Richardson
Dallas, Texas

I've observed, instructed, and/or flown about 40 more times since the January meeting. These flights, most by beginning Skyters, has helped tremendously to crystalize, for me (as well as my best flying friend/critic, Scotto), useful data on this new activity. Here are some of our findings:

1. ACCURATE PRESSURE MEASURING DEVICES FOR THE DRIVER ARE A MUST.

2. A FORMULA for how much PRESSURE to tow at, per pilot/glider combination has evolved. I recommend that beginners start with 60% of G and increase that to 70% once the pilot learns to to play "pushy pulley" on the bar (move around trying to "increase" climb/control performance). If you go much above 70%, you are going to start breaking weak links regularly due to line snap-back, turbulence, yaw oscillations, etc.

Example:
Pilot weight
- 168 lbs
Glider weight
- 062 lbs
Total
- 230 lbs
Times 60%
- .60
Recommended tension
- 138 lbs
Driver tow at
- 062 lbs

3. The pilot should select his weak link based upon one G. Since one loop of line must have a knot (square or barrel), that material will yield about 75% of max, so he gets, say, #24 line which breaks at 290 lbs (approx.) times 0.75 for a weak link breaking force of 218 lbs which is approximately 1 G (this flying weight). I recommend that beginners start out 4 to 6 line gauges light and work up as they gain experience. I.e. if your pencil says use #24, go to #18 when you start out. If you break a weak link - don't go to a bigger one - learn to run and control your ANGLE OF ATTACK better! The idea is to GREEEASSSSE off the field, not jump into da sky guy! like some criminal wuffo with his stolen standard at the levies. Moral - use finesse - not more muscle, especially at the entry level. If what you're doing doesn't result in consistent take off and climb - refine your take off technique.

4. Small gauge tubular ((hollow braid)) polypro rope of 1/8 or 3/16 inch girth ((diameter)) has proved workable and inexpensive to replace when wear becomes a problem. They have dual advantages of stretch and low drag. A 500 ft reel's about $10.00 at Marine Ind. Supply in Dallas - 8330 Harry Hines Blvd. 631-2300.

5. If pilot must PUSH OUT to climb off of the ground, he INCREASES YAW INSTABILITY by moving the center of mass behind the center of pressure. STABILITY RETURNS WHEN THE PILOT RETURNS TO NEUTRAL, which means that center of mass is returned to or in front of center of pressure. Attach top connection point as close to the glider's CG as practicle and work out alternate ways to keep the bridle from tangling with your helmet/radio antenna, unless you don't mind exceedingly long take off runs and yaw instability when you push out to FINALLY start climbing. Humm?

6. My bridle is a 40 ft length of 1/4 inch poly rope having only one release and stripping off with the tow rope. It has proven workable and reliable (85 tows so for). I'm naming it the Richardson T.O.W. bridle. (Or should I say: This One Works?) See illustration.

7. The attachment of the Richardson bridle to your harness has proven to be a critical issue, especially if you use an auxiliary (home made) rope tied to the risers of your harness. Insure that the tow ring clipped to it isn't higher than the breast top of your harness, lest in whipping around - the ring, rope, or whatever smacks you in the mouth. Ouch! It's happened.

8. Using a Horse Bridle Quick release has worked okay for me, so far. Keeping it out of the dire is the secret. So, how or where it is mounted is a function of its reliability. But, I concur with my peers, that the best release is the Sweitzer AA approved sail plane - so long as IT doesn't get bent or DIRTY. Their cost is a significant factor. In my opinion, the best location is mounted on keel with motorcycle handle cable or choo-choo train pull toggle actuators.

9. Reminder - make the release end of the Richardson T.O.W. Bridle at least as big as your thumb and finger touching at the tips to ensure that it won't snag in the jaw of a Horse Bridle Q. R.

10. PROSPECTIVE Skyters should definitely ride as observer and serve as driver before attempting to skyte on t'other end.

11. Do not tow behind a crew who has drinking or tokeing. Weird accidents "seem" to occur when this advice is broken. Also, DO only use a pilot as a driver if at all possible. Call it prejudice, but it's my observation that under "pressure" situations, pilots understand quicker what's afoot and respond more consistantly to what's needed. I've been encouraging new faces who want to start skyting to (a) Help at the glider end one or two times, (b) ride as observer in the tow vehicle a few times, (c) drive 4 to 6 times, and (d) then - if time, conditions and personal inclination are still go - set up glider and put on bridle and radio, etc. When not sure - communicate - don't skyte.

In fact, all of the above is to pass along data - not an advertisement and encouragement to skyte.

12. But if you decide skyting is for you, my address is 3624 Theater, Dallas, TX 75204, and my phone number is 522-9831. Call me. I swap instructions for a ride and a fly.
+
Bare Minimum Materials for Richardson T.O.W. Bridle

Driver
Driver's Pressure gauge
spotter
1000' 3/16" poly
1 g weak link
locking caribiener
Release
Knotless Loop
40' 1/4" poly
non-locking Caribiener
Belly Band
Release Line
*
1984/03-03

Ed note:

Although I am in general agreement with the substance of the above article, in the interest of safety I feel compelled to express the following semi-counter viewpoints:

2. Instead of 60%, I recommend that beginners start with only about 35% of "G" or roughly 75 lbs of towline tension and gradually increase it as they gain experience.

3. Whether you use this method or any other to choose your weak link, always test your weak link configuration to varify that it does indeed break where you want it to. NEVER DEPEND UPON THEORETICAL CALCULATIONS ALONE.

11. In selecting a driver, my advice is to use the BEST QUALIFIED DRIVER you have available, irrespective of whether or not they are a pilot. My wife is a non-pilot and is without doubt the best qualified driver I have ever towed behind.
*
1984/03-04

THE LIBERTY, MO BRIDLE

Dear Donnell,

My brother and I were on a 400 mile "goose chase" today (Feb. 16) and came home with no glider downtubes, but we were shown a swell single release system being used by the fliers at Liberty Landing Airport, Liberty, MO.

The folks at Liberty are towing gliders with the ultralight they manufacture, the Starflight TX1000. The U.L. uses a sailplane release, while the glider has a keel mounted release of their own making. The release is based upon the same principle as a Jumar, used in rock climbing, or a yachting cleat. I have tried to represent the system in the accompanying figures.
+
Fig. 1. Mounting position.

Keel mounted release
Keel
Pull lever and line
+
Fig. 2. Side plate removed.

Mounted to Keel
Jamming plate
Eccentric Cam
Offset hole for pivot point
Pull line
7-9 mm perlon
+
Fig. 3. Front or end view.

Keel
Side plate
1/8" Aluminum
Eccentric Cam
3/8" Aluminum
7-9 mm perlon
Jam plate
3/8" Aluminum
+
I'll try to explain as best has possible how the system works and one trick to remember.

The release works on a piece of 7-9 mm perlon at the keel line mounting position (CG). The release is solidly mounted to the keel and no other release is needed on the glider. The bridle is hooked to the apex ring, then threaded in the Hewett manner. The bridle is 7-9 perlon held at the keel position by their jam/release device. Activating the release allows the bridle to slip clean through the apex and body rings leaving nothing but the pull line and release in position.

The trick is to thread the body ring so you do not get a face full of rope on release.

Once again I have tried to diagram what happens under their system:
+
Fig. 4. Flying on tow.

Release
Apex ring
Body ring
+
Fig. 5. Releasing

Body ring
+
On release, the free end should come loose in such a manner that the free end snaps around near your feet instead of near your head!

I have NOT seen the system in action but hope to duplicate the release and test out their methods. We do not use cocoon harnesses, as they do, so obviously that presents a problem of the bridle tangling with the stirrup or knee hangers.

When we try it out we'll try to give you clearer drawing (I believe in miracles, I guess!) or perhaps plans if it works well.

I like the concept. I'm sure there are other solutions to the single release question, however.

If ever we find down tubes, we'll be reporting back!

Joe and Lisa Sztukowski
Des Moines, IA
*
REPORT FROM FLORIDA
*
1984/03-05

Dear Donnell,

I'm interested in getting all the information I can on Skyting and find that most of the magazines are three to six months behind with current information. I also want to thank you for taking the bold steps necessary to develop this phase of hang gliding.

We in South Florida have been skyting for about six months now and have had varying degrees of success. We use a 1/8"-3/16" combination polypropylene line with the 200# weak link - similar to what has been shown in the magazine recently. Line length varies with the site and can be as much as 3000'. This is the biggest problem for us as reeling in 3000' of line is always tricky - depending on how many trees, bushes, or fences it is lying across. The biggest problem with this system is finding a suitable place to lay out 3000' of line with no wires, etc. - and still have a mile or so in which to drive. Straight, traffic-free roads, with no wires and no interscetions over safe terrain are almost non-existant in this populous lower corner of S.E. Florida. I believe that the only form of hang gliding that will ultimately be popular here will be from aerial towing via an ultralight tug, but this is still quite a ways off as far as I can tell.

We use two methods of releases here. One is the popular two-three ring type you are familiar with and it works all right. The one I am currently using, I believe, is simpler and safer. It consists of a marine "Sheet Stopper" made of high quality aluminum, mounted on the keel of the glider as close as possible to the hang point. This is the ONLY RELEASE and I use a single stainless steel ring on my harness. See diagrams.

With this system (1) I obtain the two to one advantage of skyting you advocate. (2) When I release, nothing is in my way on the glider - the only modifiation is the sheet stopper attached via hose clamps to the keel (5 minutes on my glider) and my harness ring. (3) The only part released is the ring with the line on it - very little to foul or break (or lose!). (4) There is no problem releasing with this release as it is designed for several hundred pounds of tension on sailboats and I have doubled its mechanical advantage using a longer A/C eyebolt in place of the short stock rod it comes with. The maximum tension theoretically applied to it is 1/3 of 200# (weak link strength) anyhow or about 70#. (5) It only takes a flick of the wrist and it releases easily with NO tension on the line at all - the weight of the line will pull it through the rings - something the "three ring circus" types have trouble with.

Some people have commented that I could get slapped in the face or eye with the line as it comes toward me, but to reduce this possibility I always reduce tension on the line prior to release. Also, my harness ring is at my waist and I have never had this problem - even under high tension releases. I am always experimenting with improvements and will pass them on to you if they are of any significance. Now for some questions - I still am bothered by the adverse yawing problem, especially with my Raven 209. It only seems to occur at low tow angles and the higher I climb the less of a problem it is. But, it is annoying and "looks" much worse to the uninitiated. How can I correct this? Will adjusting the bridle length have any effect? We tow about 100# tension (with a hydraulic gauge) - sometimes up to 150#, depending on the conditions.

Another question - Some of the pilots with double releases (two three-ring types) are now releasing the upper release after climbing out 400-500' - this enables them to climb at a steeper angle and only tow from the harness (center of body mass point) release - seems to work out O.K. - What are your thoughts on this?

Once again I would like to thank you for being the one to bring land, and towing in general, back into the realm of safe hang gliding.
+
Fig. 1. Sheet Stopper Release.

Keel
Front
Stanless Hose Clamp
Mounting Plate
Note off center shaft
Aircraft Eyebolt
Release Line
Pull to Release
Skyting Bridle Line
* Use ONLY braided lines! Don not use a twisted line as it may foul. Braided yachting lines or perlon, etc. work well - I use 3/16" braided - am experimenting with 1/4" braided Samson.
+
Fig. 2. Bridle System.

Important!! Use only braided yachting or climbing rope - they will not twist of foul on themselves.

Sailing Sheet Stopper
Stanless Ring
Pull to release
Line releases this way
Stanless Ring
+
Cal W. Tax
Miami, FL
*
1984/03-06

Dear Cal,

Concerning the adverse yaw problem, there is little I can add to what I said a year ago in SKYTING #12. I still believe that the primary cause of adverse yaw is that attaching the bridle to the keel of the glider mildly violates the skyting criteria No. 4 (Attach bridle to CM of components) when the "crossbar floats" because the glider's mass is NOT in the keel but in the leading edge/crossbar/sail structure. I also believe that the proposed solution is still valid, namely that the upper bridle line should be attached to the cross bar instead of the keel. The problem is in finding a way to attach the line to the cross bar without interfering with the floating cross bar action or possibly weakening the structure or the glider (bending or breaking something near the heart bolt). Although I have been warned against it (for reasons just mentioned), I have towed with the top bridle line attached directly to my glider's cross bar. There is no question in my mind, this technique definitely reduces the Gemini 164's adverse yaw tendency to approximately the same as that of free flight. But I cannot recommend this technique unless you are absolutely sure that your glider is structured for cross bar towing. (Check with your manufacturer who, I am certain, will say "NO!")

As far as bridle length is concerned, no, I do not believe it will effect the adverse yaw tendency to any measurable degree. The bridle needs to be as short as possible - in order to reduce rope and complications (twisting or tangling) - but long enough to clear the pilot and basetube without hampering movements.

Adverse yaw is a function of towline tension as well as tow angle, so you may want to simply reduce towline tension at low tow angles and increase the tension at higher angles. However, 100 lbs does not seem to be too high to begin with, so this may not be your solution.

One last thought on the adverse yaw problem. Several pilots have reported that proper flying technique can essentially eliminate adverse yawing. The idea here is to give the glider a strong "punch" on the control bar as it tries to oscillate through the neutral position and immediately reposition the body back to neutral. In other words, control the glider with quick "punches" instead of long "pushes".

Let me know of any of these ideas work for you.

Now concerning the body towing concept. Body towing is perfectly safe as long as the tow angle is high, BUT DO NOT ATTEMPT BODY TOWING AT LOW TOW ANGLES. A strong forward pull on the body acts below the glider-pilot CM and causes a severe pitch up. At least one pilot has been killed trying to take off using body tow. Once the tow angle is large, however, there is only a slight difference between body tow and CM tow (the body tow thrust line misses the CM of glider-pilot by only a few inches at most). There is a difference in the trim of the glider and the "feel" of the towing forces which I, personally, do not care for, but that is a matter of personal preference, not safety.

Donnell
*
1984/03-07

CANADIAN REPORT
GOOD AND BAD
(Fatality)

Dear Donnell,

We have been towing with the new bridles you sent us, with no problems so far. Doing trial releases on the ground, we found that if the keel line catches on something 1-2 feet from the point of release, the entire bridle will not release. This is not considered to be a major problem, however, because the chances of it happening are almost nil and if it does happen, the pilot just has to release his belly line and the release at the apex will let go.

We are using 1000 ft of 1/8 inch braided nylon which stretches approximately 10% at 100 lbs. We have found that this gives us enough stretch to take off in no wind with only a few steps. If we add more line, we will add line that will have a minimum amount of stretch.

Howard Vandal has had 9 flights, myself 7, and Stewart Midwinter has had 5. In all these flights we didn't have a weak link break except in my 3rd launch (because we dragged the weak link on the ground) with no bad results. The highest tension we have towed at is 150 lbs. I prefer to be towed at between 70-100 lbs.

Howard let the nose of his glider up in about 20-25 mph winds and climbed out behind the car when it was parked. Once he flew around behind the parked car for 20 minutes with the tension varying between 40-70 lbs. Quite regularly we have towed up into stronger winds and have climbed out behind a parked car.

We are using 2-way voice activated Maxon 49-B FM Transceivers for communication and they are working very well, although the driver has to be sure his antenna is out the window. I am a strong advocate of using radios for towing, which I am sure increases the safety of towing.

We have generated a lot of interest in the Hewett system. I have been recommending to anyone interested to subscribe to your newsletters. We found one group of pilots towing with your bridle who used no weak link and no stretchy line, on a winch which wasn't calibrated. We have shown them the errors of their way. (Skyting #11, A Broken Leg in California.)

Unfortunately, there was a group of pilots which we didn't hear about in time. Just this weekend a pilot was killed towing. They were towing a "Standard" behind a snowmobile on a forzen lake 24 kilometers west of Barrhead, Alberta. Their system used 1/8 inch steel cable tied to the keel and to the base tube of the glider. Apparently they had gotten away with this for 3 years but this time the glider apparently locked out and dived in from 40 meters.

Chris Sali
Calgary, Alberta
CANADA
*
1984/03-08

ACCIDENT REPORT

Dear Donnell,

On Sunday, 11 December 1983, at approximately 12:15 pm, intermediate pilot Rich Moore was injured while skyting his Moyes Missile 180R at the Woodborne Airport (Air Base) Blenheim, New Zealand. The accident occurred during Richy's second flight. The wind on T.O. was approximately 60 degrees off which doesn't seem to effect us when towing. Richy had a good T.O. and seemed to be controlling the glider in a satisfactory manner. When he was at approximately 200-400 ft, the glider nosed down and tucked in an inside loop. At the bottom of the loop the glider's wings folded up and it flat spun into the ground. Richy was very lucky to sustain only a concussion and a dislocated shoulder. The glider's airframe was essentially totaled: broken keel, left crossbar, kingpost, battens, right downtube, badly ripped sail.

On seeing the video, the bottom release released prematurely causing the glider to tuck. In my opinion this is the theory of the accident: When the glider and pilot are under tow, the force is distributed between them proportional to their respective masses. When the premature release occurred from the pilot, the full towing force was applied to the glider (at a point well above the center of mass of the combined system) causing the nose to pitch down. Beyond a certain point, inertia must have taken over.

According to Allen Ingles (driver) the pressure on the towing line never exceeded 130 lbs (which in actual figures is around 200 lbs). This is well within the limits of towing as the weak link breaks at 230 lbs.

Notice the similar sequence of events to the serious skyting accident reported on page 1 of the Skyting No. 19. The harness had been used successfully that morning by myself and once by Richy. The lower release failure may have been because of (1) incorrect assembly of 2-ring release, or (2) lower release may have caught on the control bar or whatever.

The other week I made up a new harness that is attached to the glider by carabinas with one 2-ring release attaching to the towline with a release line going to the pilot. The system is the same as yours except we have only one release which is where the towline is attached. The rest is clipped on semi-permanent. Also, we attach the release line to the speedrail, etc. the whole thing releases automatically.

By the way, on your 2-ring release bridle use a split pin that is too small to go across the release ring. That way the release cannot be assembled wrongly.

This was recommended by New Zealand Civil Aviation Air Accident controller. The split pin, smaller than the ring, will fall out if not assembled properly, but will hold if assembled correctly.

Dave McGill
Blenheim
NEW ZEALAND
*
1984/03-09

SINGLE RELEASE ANSWERS

(Ed: This letter was written in answer to some questions posed in SKYTING NO. 21.

Dear Donnell,

1. HOW IS THE RELEASE ACTIVATED?

The one I use has a stainless steel cable and housing, with a motorcycle lever mounted on the base tube. My release and another that I have, came from a tow bar made by George Dyer in California, for me. In a situation where the lever is pulled and the release does not work, all I do is pull on the cable housing and the release opens. My other release has a line that goes to the base tube and is tied there. We adjust this line by holding the glider in level or slightly high angle of attack (see picture). The line should be slack for bridle stretch. If you forget to hook the body line from the bridle to you, the release will work at the end of the release line or cable. We always hook up to the glider first, then the body line.

2. IS THERE A LOT OF SLACK IN THE RELEASE LINE?

No, not as you can see from my picture. It's not enough slack to cause any problem in operating the release.

3. HOW DOES THE RELEASE WORK ON THE SLACK TOW LINE?

The weight of the tow line at all angles of attack to the glider is enough to release the line. This is my point on using the single release. All you have to move is the weight of a small piece of metal on a pivot.

COMMENTS

I have made a three ring release, but have not used it yet. I don't expect any difference in it than my release mechanism to hold the assembly up after releasing.

The Schwitzer Tow Release as used with sailplanes, is a good one to buy. John Stokes has one that he bought at the aircraft supplier in Memphis. He had a motorcycle shop put a cable and handle on his. The cable should be set to length the same way as with the rope, or you could mount a rope to activate it.

Donnell, I hope this will answer your questions on the single release and the pictures will also help to show everyone what I am using. I will be glad to answer any questions that you have.

Butch Pritchett
Finley, TN
+
RELEASE LINE OR CABLE

CABLE & HOUSING TO MOTORCYCLE HANDLE RELEASE
1 1/2 RING
+
FROM THIS SIMPLE SKETCH YOU CAN SEE THAT IF YOU SET THE RELEASE PULL LINE OR CABLE SLACK AT LEVEL OR JUST BELOW, PLUS A LITTLE FOR BRIDLE STRETCH, YOU WILL HAVE JUST THE RIGHT LINE LENGTH.

RELEASE LINE OR CABLE
ANGLE OF RING WITHOUT PULLEY SYSTEM
ANGLE OF RING WITH PULLEY SYSTEM

B.P. 1-27-84
*
TETHERED SKYTING
*
1984/03-10

Dear Donnell,

2000 ft teather flight on 1800 ft rope!! Impossible? Not at all!

In my last letter to you (#21) I left out the part about Don Ray claiming he made it to 2000 ft. I was sure that it must have been a reading error - intense low pressure moving in or the hardware store selling us more rope than we paid for. That was until I made it to 2000 ft three weeks later. (My apologies, Don.)

I took two altimeters up and they both agreed. I measured the rope when I got home and found that the two 600 ft lengths of 3/16 inch poly (spliced together) now measured 1230 ft. The rope has retained some stretch from much use and looks tighter now than when it first came off the spool. The third 600 ft length of rope was 1/8 inch nylon and now measures 625 ft. (Total measured length was 1855 ft.)

At 2000 ft Don estimated an angle of 80 deg. I thought 70 deg, so we compromised at 75 deg. Now if my math is right, we would need 2071 ft of rope to be at 2000 ft with a 75 deg angle. That means we had 271 ft of stretch (15% with this towline combination. (Ed. I get 216 ft or 12% stretch which seems a little high but not unreasonable.) I attained 2000 ft AGL without breaking my 1 g (250 lb) weak link.

Below 1800 ft, at hands off, I would descend, but between 1800 ft and 1860 ft I would maintain at the "hands off position". Above 1860 ft the glider would ascend by itself until I got to 1920 ft. Then I had to push out to get to 2000 ft AGL. This teather flight lasted for 45.5 min. When I landed, at sunset, the flag was hanging straight down.

During this teather flight Gene Stone ran the snow machine downwind-crosswind for 1/2 mile to an ice fisherman to check on the Super Bowl score. I was able to maintain altitude by pushing out at 1900 ft AGL and drifting backwards and crabbing to stay down wind of the snow machine. Temperature was 15 F and the air speed was 25 mph, so the wind chill factor was -22 deg Fahrenheit. I almost froze a posterior portion of my anatomy.

Gene Stone tells me that his Fire Fly 2B will track hands off behind the snow machine. My Maxi IV will wander off to one side or the other without input. Donnell, would you expect all gliders, like my Maxi IV (that I have to high side the bar to stop a turn) to not want to "track?" If you do, then maybe we all should give some thought as to what type of glider we start a beginner on.

Only Gene and I flew on Jan 22, 1984, so we didn't get to stake out one teather flyer and pull the next on up with our other rope. Don Ray stayed home to watch the Super Bowl! Can you imagine that!?

How about some of our skyting boys in Kansas or Nebraska find a good tow area and all the rest of us meet them there for a Skyting event? Maybe some one has a better idea.

Bill Cummings
Hoyt Lakes, MN
*
1984/03-11

Dear Bill,

I appreciate your keeping me informed about your progress. You are now well ahead of me in tethered flying experiences. After two broken arms, I have backed off trying anything which appears to be beyond my present skill level. And since I currently have no one here to fly with, I haven't progressed far. It's good to see others doing what I would like to do. As Henry Wise said when he couldn't hang glide because of his broken ankle (skiing accident), "The next best thing to doing it yourself is watching a friend do it!"

Now in answer to your questions, Yes, I do expect all high performance gliders to wander off to the side without input. This is because of the "floating crossbar". See Skyting No. 12 for the theoretical (speculative) arguments. In essence, when the upper bridle line is attached to the keel instead of the cross-bar itself, the forces tend to cause the glider to adverse yaw. The solution is to use a glider that does not adverse yaw, or devise a safe way to attach the upper line to the cross bars, or teach the beginner to correct the adverse yaw tendency from the start. As towing becomes more prevalent, perhaps the manufacturers will build in towing attachment points to alleviate the adverse yaw tendency. But that is some time in the future.

I hope someone in the mid-west will take your suggestion and volunteer to organize a skyting meet this summer. How about it, someone?

You know that Rich Pfeiffer is organizing a Skyting Launch XC tow meet in California in July based upon a sailplane format. I think it would be great if the local skyters in an area devised their own tow meets and invited their neighbors. By devising primarily "fun" tasks and exploring their own ideas of what constitutes a "good" meet, perhaps the days of amateur hang gliding meets can be brought back. Then as the better formats are developed, competition could be arranged between the various regions. Then instead of "Cummings beat Hewett", the headlines would read "MN beat TX". This would strengthen local involvement and possibly induce non-flyers to back their local boys and girls.

Donnell
*
*

1984/04
*
SKYTING NO.24
APR. 1984
*
1984/04-01

AEROTOWING UPDATE

by Donnell Hewett

There is no doubt in the minds of many that, of all the forms of towing hang gliders, ultralight towing holds the greatest potential for future growth. Ultralight towing enables pilots to reach higher altitudes and uses less land area than any other forms of towing. It is the only form of towing that seems practical in high density, metropolitan areas where land is at a premium, back roads are non-existant, airports are crowded, and the use of lakes is restricted. And since most of the population of the United States (as well as most of the world) lives in such high density areas, most of the future potential hang glider pilots also live in these high density areas.

Aerotowing is also the only practical means of "trolling" for thermals over flat lands. (Sure, you can "troll" over water, but the chances of finding a good thermal over water is not nearly as good as finding one over land.) Therefore, aerotowing shows more cross country potential than most of the other forms of towing.

Furthermore, of all the forms of towing, ultralight towing shows the greatest potential for commercial development. After all, most hang glider dealers are also ultralight dealers (or else have close friends that are ultralight enthusiast), so they either already have (or can readily get) the equipment needed for aerotowing. And since the same field can be used for aerotowing as is already used for ultralight flying, there is generally not even a need to go out and look for a place to tow. And, finally, once aerotowing is perfected, there is plenty of room for growth and profit. Both new and repeat business is essentially guaranteed as more and more pilots come back time and again for equipment, training, and tows. (Let's face it, few groups and no individuals can afford to set up and maintain an ultralight towing operation simply for their own hang gliding enjoyment. So aerotowing requires either a professional setup or a serious group effort.)

Small wonder that the established hang gliding community - dealers, manufacturers, USHGA leaders, and other serious pilots who are concerned about the future growth of hang gliding - small wonder that these people are extremely interested in aerotowing developments. It fits them like a glove.

Now if only the FAA would get out of the way and allow things to develop naturally and safely as they should. In fact, ultralight towing is inevitable - all the FAA is accomplishing with its current policies is slowing things down, making outlaws out of the pioneers, and increasing the probability of serious towing accidents by stifling free communication between current participants.

TOWING AND THE FAA

Actually, these comments regarding the FAA and aerotowing may be a bit unfair. From all indications I can gather, the FAA is not diametrically opposed to ultralight towing. It is just that current laws do not really take ultralight towing into consideration, and the FAA officials had to make some kind of interpretation of the existing laws in order to make a ruling on ultralight towing. (They had to make some kind of ruling when a well-intentioned law-abiding Texas pilot asked them what the law was.) Naturally they chose to interpret the laws conservatively (from THEIR point of view) until more appropriate laws could be enacted.

Where the FAA and I disagree is in their interpretation of the existing laws and in their attitude toward new developments. I believe that in a free society everything that is not specifically prohibited should be allowed, while the FAA is taking the position that everything that is not specifically allowed should be prohibited. In other words, I believe that until specific laws are established governing ultralight towing, it should be permitted (This is the way hang gliding, itself, was originally handled - and quite successfully, I might add.), while the FAA feels it should be prohibited.

But on what grounds does the FAA presume to prohibit ultralight towing? Well, the law clearly states that ultralights are specifically to be used for recreational purposes and not for services or for commercial purposes. The FAA feels that the ultralight tug in not being flown for recreational purposes but is performing a service. (Of course, according to this logic, boats used to pull water skiers are not being used for recreational purposes either. I wonder what fraction of the public would agree with this opinion.)

Furthermore, the FAA feels that if they allowed unrestricted ultralight towing they would be opening a "Pandora Box" for commercial ultralight operations. Indeed, the FAA has apparently already adopted the position that ultralight towing IS a "commercial operation" even if it is performed free of charge by the hang glider pilots, themselves. (Again, such a position is probably indefensible in the long run, but it does buy the FAA time to formulate a better stance.)

The FAA also asserts that, in the interest of safety, no one should be allowed to tow with an ultralight unless he (1) gets his aircraft certified and (2) holds a valid pilot's license. Unfortunately, the only certification catagory open to ultralights is the "experimental aircraft" catagory, and by law "experimental aircraft" cannot be used for towing. So under FAA interpretation, it is impossible to legally tow with an ultralight. And since the FAA is the "Judge, Jury, and Executioner" in this matter, it is going to take time to change their minds.

Fortunately, the FAA recognizes that provisions for ultralight towing must eventually be made. But there are other problems which it considers to be of a higher priority. So it is going to take time before this problem is resolved satisfactorily. In the mean time the FAA maintains that ultralight towing is illegal, so "Don't do it!"

But because ultralight towing is a low priority item, the FAA is not making an extensive effort to enforce this edict. I understand than no official notification has been sent out to all the local FAA officials regarding the matter, so that many FAA officials may not even be aware of the legal status of ultralight towing. (I may be wrong here, but perhaps this explains why the illegal status of ultralight towing has not been publicized more extensively in the normal hang gliding literature.) Apparently, the emphasis on enforcing this law rests primarily with the local FAA official. There seems to be a couple of unwritten rules concerning ultralight towing: "Don't ask!" and "Don't rock the boat!"

It's a sad situation, but if you pretend that you don't know the law, and if your local FAA official doesn't know the law or looks the other way, and if you are careful enough so as not to have an accident or otherwise call attention to yourself, then the chances are good that you can get away with aerotowing. In other words, if you maintain a low enough profile, you can probably aerotow without FAA interference. But if your local FAA official is determined to enforce the law of if you have an accident or go public, then the FAA can charge you $1000 for every aerotow violation. And that's a pretty expensive tow. (Me? I think I'll stick with surface towing!)

EXEMPTION STATUS

In an effort to legalize towing, the USHGA, primarily through the efforts of Dennis Pagen, has submitted a request for an ultralight towing exemption. Like the tandem flying exemption, it requests that under certain circumstances, ultralight towing be permitted. This request was submitted in mid March, and it is expected that a minimum of 120 days will pass before any possible action will be taken by the FAA. Who knows, perhaps through this effort, by the end of the summer, aerotowing will be legal within the U.S. air space. Dennis is optimistic, saying that the FAA is glad the USHGA took the initiative in this matter. By studying the problem and proposing a solution, the USHGA not only saves the FAA considerable time and manpower, but also increases the chances of our getting a law that meets our needs and doing so in the minimum amount of time. Again let me say that USHGA needs the support of every hang glider pilot in the USA - and that means YOU! If you are not currently a member, join now and help increase the bargaining power of your hang gliding organization.

AEROTOWING TODAY

Despite the current interpretation of the law by the FAA, certain ultralight towing developments are still being made in the USA. In fact, if you will look at the ads in hang gliding publications a few months ago, you will notice that, prior to the FAA ruling, several ultralight towing systems were approaching the commercial stage of development. Such operations have now essentially shut down. But the technology is ready and waiting for when the restrictions are lifted.

In addition to commercial applications, certain local groups have been continuing their own developments of alternate ultralight towing techniques. I believe I have said this before, but from all indications, the only three major difficulties associated with aerotowing are (1) power, (2) speed, and (3) center-of-mass towing. Other matters, such as rope lengths, weak links, reliable releases, take-off and flying techniques, etc., although important, are relatively easy to solve. But the "three biggies" can make it impossible or impractical to aerotow with certain available ultralights.

And that's the catch. One of the things that makes ultralight towing so appealing is the ready availability of ultralights to be used as tugs. But unfortunately, MOST CURRENTLY AVAILABLE ULTRALIGHTS ARE NOT SUITED FOR SAFE AEROTOWING. To be suitable, they must meet the following conditions:

(1) POWER - The tug must have sufficient power to take off and climb while pulling a hang glider. This means that there must be adequate acceleration for the glider to be airborne in less than say 100 ft or so. If the take-off run is any longer, the pilot and/or launch assistant is almost certain to fall on takeoff. The climb rate under tow needs to be about 500 ft/min or so in order for the craft be able to clear obstacles and reach reasonable altitude in a reasonable time. In short, the engine must have about 50 hp and develop about 300 lbs of thrust. Anything less is probably compromising safety.

(2) SPEED - The speed of the ultralight must be compatable with that of the glider. Unfortunately, most ultralights which have the power to tow safely are also designed to fly faster than hang gliders normally fly. This means that either the tug or the glider (or both) is required to fly in an abnormal situation. Since the maximum speed for safe towing is around 35 mph, then the tug must be capable of providing the necessary thrust and control at or below this speed.

(3) CENTER-OF-MASS - Some method must be devised to distribute the towing force through the center of mass of the tug. (The reason is the same as that required by "skyting" when it insists on distributing the tow force through the center-of-mass of the pilot-glider.) Because of the geometry, this is a very difficult task to accomplish on an ultralight having a tail. (Yes, it is possible to attach the towline to the tail of such a craft, but this can be quite dangerous in turbulent conditions - i.e. in cross-country, thermal conditions.)

TRIKE TOWING

Of all the ultralights available today, trikes seem to be the most suitable for hang glider towing. After all, trikes ARE hang gliders, so a properly powered and rigged trike is automatically compatible with hang gliders. If I were a betting man, I'd put my money on trikes to win the "ultralight tug race".

Since trikes are much more common in Europe than in the U.S. and since center-of-mass towing received more early support from the establishment in Europe than in the U.S., then it is not surprising that the Europeans are generally ahead of us in trike towing techniques. This does not mean that the U.S. has done nothing, of course, for Paul Whitehill and Chris Bulger, of Flight Designs, developed the first widely publicized ultralight towing system in the U.S.A. - a trike system. But the French, apparently had a similar system almost two years ago. And since I have been able to obtain more information on the French system than any U.S. system, it is the French system I am going to describe below. (If anyone else wants equal time, send me some information!)

Figure 1 illustrates the aerotowing system developed by Gerard Thevenot, co-owner of La Mouette Inc, of France, the largest hang glider manufacturer in the world. (Gerard was also the 1982 World Champion hang glider pilot.) Components of the system are as follows:

The tug is a 211 sq. ft. Azure 19 hang glider designed for tandem flying and powered by a Cosmos trike using a 432 cc Fugi Robin engine with a reduction drive developing 50 hp and 330 lbs of thrust. A large panoramic rear view miror enables the tug pilot to observe the glider in flight.

The towline is 180 ft of 3.5 mm nylon shroud line with a 185 lb weak link tied to each end and a small retrieval drag chute attached in such a manner that it automatically deploys when the glider releases. This prevents the towline from flying back into the propeller as well as keeping the towline above the tug when it descends to land.

The front weak link is attached to a cable which passes through the hollow hub of the propeller shaft to a pair of vice-grip pliers attached to the frame of the trike and modified so as to be easily released by the tug pilot if necessary. There is nothing mounted on the forward end of the cable so that when the vice-grips are released, the cable slips easily through the hub completely releasing the glider from tow. (NOTE: By attaching the towline to the tug through the hub of the propeller (whose thrust line passes through the center-of-mass of the trike) the center-of-mass problem is essentially solved. No matter how the glider moves, it has very little effect upon the tug pilot's ability to control his craft.)

The rear weak link is attached to a short leader hooked to a sailplane release. This release is attached to the short lines tied to the shoulder straps of the pilot's harness and activated by a cable held in the pilot's hand.

Since the system is not a true center-of-mass bridle system (pulling on the pilot instead of the glider-pilot center-of-mass) a double French connection is used to support the pilot and make it easier for him to control the glider in the resulting out-of-trim condition. (NOTE: I believe the double French connection is essential to the safe operation of this system. Without it, body towing could result in severe pitch control problems, especially in turbulent conditions. I'll write an article on how all this works in the near future.)

After a year and a half of testing, Thevenot was ready to introduce his system to the United States. He joined forces with Jean Michel ((Jean-Michel)) Bernasconi (President of Pacific Windcraft Ltd. of California) and Mark Airey (formerly associated with Kitty Hawk Kites Inc. of North Carolina) to form a company (Skylines Enterprises, Ltd. of California) for this purpose. Apparently they were all geared up to introduce their "complete, professional, and time-proven" aerotowing system to the American market when the FAA clamp-down occurred. Even so, they went ahead and conducted a series of previously scheduled towing clinics beginning at San Francisco and spreading across the country to New Hampshire. Considering the favorable impact this tour has had upon the attitudes of the hang gliding establishment toward aerotowing (Many "non-towers" and "control-bar-towers who would never try a "skyting" system got their first taste of "center-of-mass" towing and were favorable impressed.), one can only imagine what would have happened if the FAA had allowed Skylines to follow up these clinics with "who-knows-what-else" they had in mind to do.

In any case, the evidence is clear that professional and proven aerotowing systems are ready and waiting for the FAA to lift its restrictions. And once these restrictions are lifted, it will not be long before widespread aerotowing becomes a practical reality.
+
Fig. 1. Thevenot - Skyline Aerotow System.

Rear View Mirror
Vice-Grip Release
Prop Hub Tow
Front Weak Link
180 ft Towline
Auto Deploying Parachute
Rear Weak Link
Sailplane Release
Shoulder Pull
Double French Connection
*
1984/04-02

KEEL POINT MODIFICATION AND WINTER SKYTING

Dear Donnell,

May I say that if you could measure your success by the input and remarks published in the "SKYTING" newsletter, then you are indeed a celebrity amongst towing fans like myself.

I would like to tell your readers about a slight modification I made to the skyting system which allows for better launches in different wind conditions. By simply moving the tow point at the keel towards the CG, I discovered it easier to launch in light wind. On the same note, moving the tow point towards the nose allows for smoother launches in stronger winds. Use caution though as too much adjustment can lead to instability. With a little experience the keel can be calibrated for certain wind speeds.

It has come to my attention that some pilots in Canada actually put their kites away for the winter. This is hard for me to understand as some of my best flights have been in the winter months. Anyone who has ever glided in to land through freshly fallen snow knows what I am saying. A frozen lake is without question the safest landing area a person could ask for. Downwind landings result in a little pride lost and a lesson is safely learned. It is said that Mother Nature pulls up her crystaline sheets and sleeps in the winter. While she is sleeping, I for one, am out dancing all over her bed. Spring is coming fast and soon the ice and snow will be gone and Ms Nature will wake up ignorant of my gained experience while she was sleeping. This can only be to my advantage when I have to meet her face to face, one on one this summer. As for all of those hybernating pilots out there, all I can say is, good luck.

Tim Churchill
Halifax, Nova Scotia
CANADA
*
1984/04-03

REPORT FROM SASKATCHEWAN

Dear Donnell,

Your system works. The hardest part of the day was winding up our 1,800 ft tow rope. We didn't get out of the city until late in the afternoon (The morning's weather was terrible - snow and gusty winds with very low cloudbase.) but we got in four flights (about a twenty minute turnaround) - tow for Kevin and two for me (my first on the 210).

We used a Ford van with a standard transmission and a Sensor 210. Our rope is 1300 ft of 1/4 inch twisted poly, 500 ft of 1/8 nylon, a loop of #18 nylon, a fifty foot leader of 5/8 twisted poly. The bridle I got from Tim Churchill in Nova Scotia for $15.00. (It has three-ring releases with a manual upper release and the automatic on the body.) The release line runs down the control bar to a loop on your wrist. The pins are hitch pins, very effective and positive.

For a pressure gauge we used a hydraulic system Kevin put together for less than $70.00. Since the piston area is close to one square inch, the gauge reads very accurately. Our initial tows were made at 70 pounds but we upped this to about 120 pounds. We found almost no adverse yaw tendancy with the tow point close to the control bar/keel juncture. (This confirms a report from the Winnipeg flyers.)

Kevin and I both read the newsletters and we both have towed before. Kevin has hundreds of hours air time and over 1000 flights. I have 50 hours in over 400 flights so we just hooked in and went up.

Thanks for your continuing enthusiam and stick-to-it-ivness.

Garth Cantrill
Duncern, Sask
CANADA
*
1984/04-04

MORE FROM SASKATCHEWAN

Dear Donnell,

Last weekend (March 3) we accomplished our first tows here in Saskatoon. Both Garth (See above letter.) and I had done 2 tows to 400 ft with the pilots in Moosejaw. Here we used 500 ft of 1/8 inch braided nylon (no parachute cord to be found here) and 1300 ft of 1/4 inch polypro. The bridle was the three-ring circus type, with a line around the pilot's wrist, and up the downtube for the top release. The bottom release had an automatic release line. A hydraulic cylinder (small surplus aircraft type available locally for about $10) was used for a tension gauge. My 6-cylinder, 3-speed manual van was used as a tow vehicle. I had the driver practice 5-10 hard accelerations to 25 mph before we began towing. We started with a line tension of approximately 75 lbs and eventually increased to 100 lbs with no problems. In fact, everything went so well it was almost boring!! Of course we used a weak link, a single loop of #18 nylon mason's line, which was found to break at approximately 195 lbs with a "barrel knot".

We used my old Sensor 210 for a glider. The thing that may interest you is the fact that despite the Sensor's fixed crossbar some yaw problems were encountered. This was more noticeable during my first tows at Moosejaw and less noticeable here - due to several changed factors. I'm not certain which factors caused the lessening of this problem here: I moved the keel attachment back to about 8 inches in front of the A-frame (previously at about 16 inches), we were towing at a lower climb rate here (500-700 fpm), and I had the other tows as experience.

I had towed previously over water and never felt like it was safe to do over land. This skyting works great!! Saved my hang gliding, as there are virtually no hills here.

I am interested in tandem towing and want to know if anyone out there has a good reel design. (Ed: Note "POOR MAN'S TAKE UP REEL" elsewhere in -this- next issue.) Electric or hand cranked would suffice but something you could build for minimum time, cost and hopefully avoid machine & welding shops. If I come up with anything I'll send in drawings.

Thanks for taking it upon yourself to do this newsletter - lots of work, I know. The more information we all have the better. Great stuff.

Kevin Caldwell
Saskatoon, Sask.
CANADA
*
1984/04-05

SAFETY SUGGESTIONS

Ted Fillmore, ((Gilmore)) of Mission Hills, Kansas, called me recently to give a few suggestions regarding skyting safety. We talked about many things and my notes are quite sketchy, so I hope this report is accurate. If it isn't, Ted, then please let me know.

Much of our conversation dealt with the threaded bridle Ted & Co. have been developing, and with suggestions for making threaded bridles safer. Here are some of these suggestions:

(1) Don't use Yacht Braid in a threaded bridle as was suggested in SKYTING No. 23. Yacht Braid is not as good as Perlon for this type of application. After all, Yacht Braid is designed for boating applications while Perlon is designed for mountain climbing applications. As a result, Yacht Braid is more flexible than Perlon and, therefore, more likely to become entangled during release. Also, Yacht Braid is generally more elastic than Perlon and, therefore, more likely to "pop the pilot a good one."

(2) Use 11 mm instead of 9 mm Perlon. Again, the larger diameter line is less flexible and less elastic than the smaller line. It is, therefore, less likely to injure the pilot when he releases or when the weak link breaks.

(3) As an emergency release device for all skyting bridle designs - and particularly for the threaded bridle design - you should tape a sharp knife to your forearm just in case the bridle becomes tangled. Do not tape it to the control bar or keep it in a pocket lest you be unable to reach it in an emergency. The tape should be weak enough for you to rip the knife off your arm without difficulty. A cheap brand of masking tape should do the trick.

(4) Do not use metal parts in any skyting bridle. Even light weight aluminum rings can fly back in the pilot's face under certain circumstances (say weak link breaks). This is particularly true if no leader is used on the bridle. Ted suggests using the rope itself as the apex loop and eliminate the body ring as shown below. There is more friction to prevent the bridle from working.

(5) As far as rope lengths are concerned, Ted recommends a 21 ft threaded bridle line and a 50 ft leader. (I understand that several of you are using pre-stretched rope on your bridles and feel that no leader is needed at all. Needless to say, we pilots who have experienced a bridle "slapback" are somewhat leery of your arrangement. Yet we would just love to be convinced that you are right. Can you give us more details on your system and tell us some of your "non-slapback" experiences?)

(6) Instead of using a Barrel Knot on his weak link, Ted uses a Bowline. He also uses a long weak link line. Since the weak link always breaks at the Bowline, the rest of the weak link line is undamaged and may be used again. So instead of having to keep weak link replacement line handy, he simply reties the one that broke. Of course his weak link line gets a little shorter each time he reties it, until eventually he has to start over with another long line.

Donnell
+
Fig. 1. All Perlon Threaded Bridle.

50 ft Leader
21 ft Bridle Line
*
1984/04-06

SINGLE RELEASE BRIDLE PROBLEMS

Dear Donnell,

"It works! It's gonna work!" I believe is how my pilot buddy Tim Burnett summed up his first hop & pop even before he unhooked. I for one was less eloquent. A wild jungle scream was involuntary!

Day one was Feb. 8, 1984, at a small state park north of Des Moines, Iowa. Or road was paved, downhill, south facing, asphalt, about 1/4 mi, with a 90 deg turn to the east at the end. We began by building a bridle with a 3/8 inch polypro. We used a 3-ring release as manufactured by High Energy Sports. We decided to use a single release at the apex. (See Fig. 1.) All lines passed over the bar. Two hundred feet of 1/4 inch polypro, a weak link of #18 twisted nylon tied as shown in Skyting #11. (Our very crude tests confirmed a break of 200 lbs +/- 30 lbs.) Fifty more feet of 1/4 inch polypro was added between the weak link and tow car.

Winds on Day 1 were 1-5 mph smooth but shifting 20 deg + to the east. Run 1 was people tow attempt with my wife Lisa and I pulling Tim, the chosen one. Needless to say, Run 1 was a no go. We elected to hop & pop with the car and had no tension gauge. I took the wheel and in seconds flying in Des Moines began to look like a REALITY!

My turn came and, after overrunning the rope and blowing my first launch, my 2nd attempt was beyond my months of dreaming and reading! Five, six, seven steps - I lifted my feet and the glider swung right over the ditch. On no! Keep flying, Joe. Suddenly, the unearthly sensation of a hang glider rising rapidly from flat ground. My gosh! I was 15 ft off the ground when I realized I was going to keep going UP if I didn't pitch my nose down. That done, my next concern was my pull line looped tightly around my wrist. I never pulled in on the bar when I released. Not good, but no problem.

My second flight, I resisted the urge to release early and was rewarded with a tow to about 90 ft for 30-45 sec, including a turn to the east for 500-600 ft before releasing for a beautiful landing next to the lake which was dotted with ice fishermen on this 40 F day.

Day 1 presented no problems on my two tows. Day 2, however, I learned a weakness of the single release system I have not read of. After my fifth tow on 2-9-84, as I attempted to flare, I got about 4/5'th of my push out when my bar stopped dead! I was effectively tied to my control bar with my body line! You see, after releasing, with the lines still fastened to the glider over my base tube, I grabbed them BEHIND the base tube and threw them in front in a loose loop as I had done the previous three flights. The loop started to slip and, not wanting it to hang up as it had on Flight 2 this day, I held the lines in my right hand as I went to the uprights. All I could do was hold on and run. The rest was a mild nose-in made mild by the big wheels I always fly with. I have attempted to diagram this in Fig. 2.

I have read many reports of people using a fixed line single release bridle. In my opinion, Donnell, it is a potentially dangerous setup for beginning tow pilots. I do not intend to tow with a single release system again without more changes. It is too dangerous except in perfectly clear areas. A low release or weak link break leaves the pilot with both hands full and no time to pull in a bridle line, in my opinion. Murphy's Law and our limited testing PROVE the finest brush can pull you out of the sky if fixed bridle lines are not QUICKLY and safely stowed. This is very difficult for a low time or a low altitude flyer.

Enough bad news! We are thankful you have shared your work in SKYTING. Hang gliding has a whole new feel since we have begun to skyte Iowa. The feeling of REAL flight as opposed to our past sky surfing has ignited our efforts to proceed, slowly, safely, and enthusiastically.

Joe and Lisa Sztukowski
Des Moines
+
Fig. 1. Towing System.

Subaru Tow Car
4 spd
2nd Gear
50' 1/4" poly
Weak Link
200' 1/4" poly
Weak Link
3-ring used as apex ring also
Pull Release Line
(1/8" poly taped loosely at midpoint)
|<-15'->|
Glider is Moyes Maxi III
+
Fig. 2. Lines Around Basetube Prevent Flare.

A. On Tow
B. Release
C. No Flare! (lines around base tube.)
*
1984/04-07

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HOBBS, NEW MEXICO
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Transmitter/Receiver with Headset
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The EasyTalk PRC-3x represents the latest state-of-the art breakthroughs in radio technology. The PRC-3x is the first low cost full duplex system available - with performance previously offered on on very high priced pro systems. Transmitting range can be up to 1/4 to 1/2 mile line-of-sight. FM operation in the low power 49MHz band utilizing this special simultaneous transmission-reception design assures clean, noise-free communication.
*
*

1984/05
*
SKYTING NO.25
MAY 1984
*
1984/05-01

HEWETT'S HEADED FOR COLORADO

The spring semester is over and my family and I are now on our way to colorful, cool, Colorado to work this summer, I hope to be able to do some playing as well, but that is (as usual) farther down the list of priorities. If some of you will get busy and let us know what you are doing, I'll try to keep the SKYTING Newsletters coming. Of course, if you don't, I'll still try - but it does make things harder.

I have made arrangements to have my skyting mail forwarded, but if you want to speed things up, send you letters to Donnell Hewett, 1274 Hwy 72, Golden, CO 80403, Ph. 303/642-3265. After mid-August, of course, you will need to send your correspondence back here at 315 N. Wanda, Kingsville, TX 78363.

Also, we will not have any spare time on the way to Colorado, but there is a possibility of having some time on the way back. So if you live on the road from Denver to Kingsville and would like for us to drop by and see what you're doing in the way of skyting, let us know and we'll see how things work out.

Donnell
*
1984/05-02

TOW MEET CANCELLED

I learned from the Hang Gliding Magazine that the cross country tow launched hang gliding meet, tentatively scheduled for July of 1984, has been cancelled for this year. Scheduling conflicts with the European championships and the Los Angeles Olympics has force this event to be postponed.

The proposed SSA (Soaring Society of America) TET (total elapsed time) format and scoring system has been accepted for use, however, by the Southern California league meet coordinators. Use of this format will provide excellent preparation for the world's first tow launched XC meet. Anyone interested in this format, please contact High Energy Sports, 2236 W. 2nd Street, Santa Ana, CA 92703 (714) 972-8186.

I was sorry to hear about this cancellation, as I am sure you were. But if we'll all remember what Rod Regier says elsewhere in this issue, "Skyting is a long term objective," then we know that it is only a matter of time until a skyting XC meet takes place. In the mean time, I guess we should concentrate on local and regional skyting get-togethers. In the long run, such "grass roots" support may be the long term foundation on which national and world wide efforts are based. Hey, anyone out there know of such a "skyt-together"? Let us know so we can spread the word!
*
1984/05-03

SKYTING CATALOG AVAILABLE

I also learned from the Hang Gliding Magazine that a company is offering a complete line of Skyting hardware for the hang glider enthusiast. A free Skyting catalog is available upon request from Midwest Motor Glider ((Motorglider)) Supplies, 2638 Roberts, Waukegan, Illinois 60087 ((60085)) (312) 244-0529. I have not had a chance to see this catalog or evaluate the quality or quantity of Skyting equipment listed in it. But regardless of the contents of the catalog, I think it is significant that the first Skyting Catalog has been published. Don't you?
*
1984/05-04

YOU'RE THE REPORTER

The above two "articles" illustrate on of the major weaknesses of the SKYTING Newsletter - "Your's Truely" frequently learns of important skyting news through other national publications. Since such information is often months out of date, I am somewhat embarrassed to print it. Yet I know that some of you are totally dependent on SKYTING to keep you informed about skyting developments. Sure you are, so I keep printing such obsolete information.

The point I am making is that it is impossible for one person to keep everyone else abreast of skyting developments - even a superhuman type of person (such as myself) and even if that one person is in the mainstream of hang glider activities (which I am not). This is especially true not that towing is becoming more and more popular and as developments are taking place at a faster and faster pace. If the SKYTING Newsletter is to fulfill its goal, its success will depend on you. (Isn't that great?) You see, I am counting on YOU to keep me posted on what is happening in your part of the country and in your part of the world.

You don't have to write a lengthy epistle on what is happening, just a short book will do the job (as long as it has all the essentials).

Do you know of any other manufacturers of skyting equipment? Have you tried any of their equipment? Did it work, or are you still recuperating? You know, it's past time some good skyting equipment were made available. Who knows, perhaps it's already here? Do you know?

Do you know of anyone giving away skyting lessons for free? If so, are they worth the money? How about for hire? Again, it's past time for good skyting instruction to be available. Where is it?

Have you heard about any good skyting accidents lately? I wonder where they all went to! Especially now that skyting activities are on the increase. Are they really becoming extinct, or just invisible? If the latter, then won't somebody be surprised when they encounter one?

What are your local skyting goals? Do you want to mingle with the buzzards or just give your feet a short rest? What kind or local records are you breaking lately? Are you a member of a real "skyting club" or do you have to go hunting for a driver? What kind of "skyt-together" are you planing to have this summer? You know, with any luck, this may just be the summer when skyting really "takes off"!

Just in case you haven't figured it out, let me tell you that I'm just a little bit nosey. I not only want to know about "world records" and "important news", I am also curious about your own "personal progress" and the "interesting things" that happen to you. For example, did you finally graduate to that 2000 ft towline, or when was the last time you shook up some unsuspecting farmer by landing in his yard right there in the middle of flatsville?

In short: since you're my reporter, how about doing some reporting!
*
1984/05-05

TRIPLE RELEASE BRIDLE SYSTEM

by Donnell Hewett
+
Note: This article was written many months ago as a supplement to be shipped with the Triple Release Bridle I was selling. At that time it was, in my opinion, the safest bridle on the market. In fact, as far as I know, it still is the safest one COMMERCIALLY available (although better NON-COMMERCIAL bridle designs MAY exist).

I am sure you have seen several recent letters in the SKYTING Newsletter written by individuals who are convinced that the Double Release Skyting Bridle is unacceptably dangerous. And experimental evidence is mounting which demonstrates that these persons are, indeed, correct.

The Triple Release Bridle described in this article solves most of the problems associated with the Double Release design. Because it does so at the expense of greater complexity, I am sure many of you will still find it to be quite "unacceptable", saying, "Why in the world are you promoting the addition of one more thing to go wrong, when the Apex Release system has already been proven to be safer and the Threaded Bridle is obviously so much simpler." In my own defense, let me say that I am not "promoting" any of the specific bridle designs - unlike some of you, I simply am not convinced which, if any of the current designs, will ultimately prove out to be the safest and the most practical. Until that time, I feel it is important to publicize the various alternatives so that everyone has a chance to evaluate the available data and make an informed decision regarding his own bridle selection.
+
There are several types of skyting bridles in use today and it is not clear at this time which one, if any, will eventually become the accepted standard of the future. In general each bridle has its advantages and disadvantages. The Triple Release Bridle System described here is the result of several years of evolution and refinement of the original skyting bridle. The primary advantages of this bridle over other designs are:

(1) The complete bridle falls away when released so there is nothing to distract the pilot in free flight or to trip him up when landing.

(2) The bridle has a low probability of tangling with the glider or pilot because the part of the release that falls away is clean, small, and light.

(3) Even if the keel line should become tangled, it will automatically seperate itself from the rest of the bridle to provide a clean release.

(4) The pilot does not have to hunt or reach for the release lever because the release line is kept in his hand. The pilot can, therefore, release himself in either the prone position or the upright position.

(5) The system will automatically release itself if the pilot's release hand is thrust severely forward or backward (as during a crash or other complete loss of control).

(6) Should the pilot lose the release line, he can still activate a complete release by pulling on the sleeve of his body release.

(7) The system automatically releases itself if the pilot fails to hook in the glider during takeoff.

(8) The system automatically releases itself if the glider noses in during takeoff.

(9) If the top release breaks or releases prematurely, the bottom release will automatically release, thereby preventing a severe pitch up and possible whip stall.

(10) If the bottom release breaks or releases prematurely, the top release will automatically release, thereby preventing a severe tuck or tumble.

In my opinion, the secret to a safe release system is reliability. You simply must be able to release when you want to and not release when you do not want to. As you can see from the above discussion, this bridle attempts to fulfill this criteria. However, there are certain known dangers associated with this bridle and anyone who uses it should be aware of the following problems:

(1) Although the keel line will release when tangled, THE BODY LINE WILL NOT. If the pilot is towing with the bottom bridle line THROUGH the control bar and somehow becomes turned sideways, there is a slight possibility that the bridle line could become tangled if the pilot tries to release. I recommend that you NOT attempt releasing under such a situation, and before you ever tow, decide what you are going to do if the bridle line does ever become tangled and fail to release.

(2) If you forget to loop the release line over your hand before takeoff or if the pull release line fails to operate properly for some other reason, then use the release sleeve on the bottom release.

(3) If the pull line is adjusted too long, it may fail to release. If it is adjusted too short, it may cause a premature release. If the pull line sleeve is clamped too high on the control bar, it may cause a premature release when the pilot goes prone. If it is clamped too low on the control bar, the pilot may have trouble releasing when flying prone. Obviously you should take care before each flight to make sure that the release line is properly adjusted to the right length and the sleeve is properly positioned on the down tube. NOTE: CHANGING PILOTS OR HARNESSES WILL NORMALLY REQUIRE THAT THE RELEASE LINE BE READJUSTED.

(4) If either of the auto-release lines should be too long, the bridle may fail to release. If either is too short, they may cause a premature release. If the top releases and the bottom fails, the glider may pitch up violently causing a whip stall and possible tumble. If the bottom releases and the top fails, the glider may pitch down into a tuck and possible tumble. These are very dangerous situations, so make sure your auto-release lines are properly adjusted. The top (or safety) auto-release line should become tight and release the middle release before the two slip rings of the bridle come together after the bottom release is released. The bottom auto-release line should become tight and release the bottom release before the glider can nose in during takeoff. NOTE: CHANGING PILOTS OR HARNESSES MAY REQUIRE READJUSTEMENT OF THE AUTO-RELEASE LINES.

(5) If either of the auto-release lines should become broken or untied, the bridle may fail to release. If either becomes twisted or tangled, or if it snags with something on the ground before takeoff, the bridle may prematurely release. Obviously, before each flight, great care should be taken to make sure that the auto-release lines are clear of potential problems.

There are other minor problems which you may encounter when using this bridle. For example, the keel line may get in the way of you head when you are topping out, the keel release ring ring may hit your head when you release, the release ring or pin may hurt your hand when you pull the body release sleeve when under tension, the bridle may come back in your face when your weak link breaks, etc. But it is assumed that you have a certain amount of common sense and know how to use it, and that you have already the back issues of SKYTING which describe these types of problems and their solutions. If this is not the case, then you have no business using this bridle in the first place. You should first learn all you can about skyting and how others are currently practicing it. Only then should you attempt to do it yourself.
+
Fig. 1. Triple Release Bridle System

Hand Loop
Pull Release Line
Top Release
Middle Release
Safety Auto-release Line
Bottom Auto-release Line
Bottom Release
Sleeve
*
1984/05-06

TOWING IS NOT SAFER

Dear Donnell,

A few thoughts pertinent to safety came to mind this rainy mid-west Thursday. I feel they are important and of general interest.

Towing is in no way, shape, or form safer than foot-launching. The increase of equipment and need for a ground crew would appear to increase the chance of error. Skyting is no doubt the way to tow, but do it right!

(1) Use a pressure gauge. It allows the driver more control when the glider is on takeoff. Low level weak link breaks often leave few landing options.

(2) Do NOT think the weak link will break BEFORE you are in a bad way! Two failures to hook in confirm the fact. I was dragged along the dirt for 25 ft before I realized I would keep going if I did not release. Darn, I would have sworn the link would have broken dragging me and my Maxi! Lyle Burnett confirmed my April Fool's day research a few days later on asphalt, OUCH! Glad I warned him to release on a failure to hook in.

(3) Short ropes (2-300') are bad news. Use one long enough to stretch properly.

(4) Use a radio for pilot to driver signals or be prepared for trouble. Relaying visual signals with an observer is like playing the children's game of telephone.

All this has been said by you, Donnell, and others. Repetition on matters of safety could convince some people to improve equipment and skills.

A final thought. Test piloting is not a game. Donnell has said before that we are test piloting. A Rockwell test pilot recently stated it would take a pilot a MINIMUM of 16 years to become a test pilot for a contractor. Think about THAT and then fly safely!

Joe Sztukowski
Des Moines, IA
*
1984/05-07

Dear Joe,

I agree that repetition of safety suggestions is important, and I appreciate you and others who take the time to write us these reminders. It is also important for controversial safety practices to be discussed in order to look at all aspects of safety. So I would like to encourage those who agree or disagree with your opinions (or who have opinions on other topics) to express their viewpoint on safety practices.

Donnell
*
1984/05-08

THREADED BRIDLE RELEASE

Dear Donnell;

One of the students in my advanced class, Mark Chamberlain, has found what may be the simplest and therefore inherently safest skyting release system. Instead of using a sheet stopper or jam plate release - which might malfunction, simply fold the rope over once and thread it through the keel ring. Then insert a pin through the in & out rope parts (Note: that the rope end does not go through the ring at release making a tangle virtually impossible). Also, the wind pressure after release tends to straighten the rope out as it heads for the ring. (See figure)
+
Fig. 1. Threaded Bridle Release.

DOWN TUBE
SMALL BRASS TUBE W/ HOSE CLAMP ATTACHED TO DOWN TUBE
3/32 CABLE
NICOS
HAND LOOP
NICOS
EYEBOLT WITH THREADS CUT OFF & SANDED
KEEL RING
+
Doug Gordon
Tempe, Az.
*
POOR MAN'S TAKE-UP REEL
*
1984/05-09

Dear Donnell,

Greetings from Hobbs, I talked to you a couple of months ago before winter set in. Haven't tried skyting lately, but have had three successful attempts on 300 ft of line. Just getting started, really. Talked to a guy by the name of Dave Church awhile back who has had some real success. I believe he is on your mailing list.

At this time I am interested in building a take-up reel for the line. Any info in that area would be most helpful. I was wondering if there was getting to be any standardization of skyting equipment? Also, I have seen these simple little three ring releases in an article, but can't seem to find them anywhere. Any suggestions?

Coming up this summer in Hobbs, the local soaring club will be holding another international soaring meet. I sure think it would be exciting to show these sailplane pilots what the lowly little hang glider can do on the flatland. I can't wait to try for some altitude. I need some more of your info though. Will give input from Hobbs as soon as I get some to give.

Merlin D. Zimmet
Hobbs, New Mexico
*
1984/05-10

Dear Merlin,

No one has written an article for the SKYTING Newsletter for specifically dealing with the construction of a take-up reel although several articles have mentioned reels and/or winches which various authors have constructed. (See Mike Lake's payout winch in #22. Gary Whitman's take-up reel was written up in May 1983 Hang Gliding.)

Personally I use a spool as shown below to reel up my line after a day's flying. (I drag the line back to takeoff between flights.)

Now concerning standardization of skyting equipment, the answer is, "No!" In fact, there you can purchase even a ready made bridle. You can see in past issues of SKYTING that new and innovative ideas are still comming in. This is the main reason that the SKYTING Newsletter exists.

Three ring releases can be purchased from High Energy Sports, 2312 W. 2nd St., Santa Ana, CA 92703.

Good luck in getting the sailplane pilots to see what the lowly little hang gliders can do on the flatland. Perhaps you should invite some of the West Texas skyters to join you in an informal skyt-in just prior to the soaring meet to see how things go. In fact, you may want to invite skyters from everywhere to come to Hobbs to fly. Considering what the sailplanes do with your air, imagine what hang gliders could do.

Donnell
+
Fig. 1. Hewett's take-up reel.

Wood Board
Pipe Flange
1/2" Galvanized Pipe
Used Spool from Rope Seller

Donnell
*
1984/05-11

THREADED BRIDLE AND RADIO COMMUNICATION

Dear Donnell,

I want you to know that the "threaded bridle" works great. I had four flights last Sunday, and releases with no problems. I had a small webbing loop attached to my harness about chest high. Through this loop I attached a caribeaner, and just snapped my line in. On one release in particular, I had high tension on the tow rope. The end of the tow bridle did "pop" my harness a bit as it went through, but no problem. I really don't think that loose end is going to be a problem.

I havn't seen anyone advertising in your newsletter yet, but I have a product that I feel is very important to Skyting safety...communication. Personally, I feel it is very important for the pilot to be able to talk to his ground crew. It doesn't make any difference how he does it, but these little radios are super. Voice activated, lightweight, and very well priced. (Ed. See advertisement on page 6.)

Merlin D. Zimmet
Hobbs, NM
*
1984/05-12

SINGLE RELEASE THREADED BRIDLE

Dear Doonell,

I hope EASTER brought peace and spiritual renewal to you and your loved ones. Lisa and I would like to extend our wish that you and your family find health and joy always.

Log time for the Skyte Iowa gang is UP this spring, and we now have around 80 tows total with max airtime an estimated five minutes on 500-600' towlines.

We do not use any type of tension gauge because of the cheap construction of our foreign cars (Subaru, Datsun) and lack of spare cash for a super-duper pneumatic or hydraulic unit. We want to use one, but felt the radios we recently bought helped safety more than a tension gauge would.

We used a 3-ring release system based on High Energy Sports advertised item. These have functioned well in high tension releases, but a weak link break gives a new meaning to the old name for these releases, a REAL "3-Ring Circus". We feel with further development, the system will work, at the expense of added complexity. My opinion is this, junk all 3-rings and replace them with keel mounted halyard releases or sheet stoppers and quit worrying about auto release lines, ripcord pins, or break cord. The single release threaded bridle works like a charm!

I now use a release purchased from a local sailing shop the same day I got the last issue of SKYTING and read of the Florida boy's success with sheet-stoppers. The release is known by its brand name of EASYLOCK I and cost $36.00 locally. This is a cam operated device as opposed to the direct action stopper used by the Floridians. We did not need to modify it in any way. An aluminum bracket to mount the release was fabricated from 1/8" Flat stock. (See fig. 1)

We still have work to do with the system on weak link breaks but a drag chute set to open on a break should put enough pull on the bridle to clear the body ring. The threaded bridle is simple, so simple you will feel like something is wrong the first few times you try it! One word of warning! If you fly with knee hangers or stirrups do not release under tension. My manhood was nearly compromised in the name of science when a MEDIUM tension release left a LARGE welt on my right inner thigh. The good news is out of nearly 20 (twenty) test tows with the EASYLOCK that one flight was the only time we experienced the 'cat-o-nine tails' phenomena. In fact Tim Burnett said the release was so clean he did not think it was working!

So much for the single release threaded bridle until we do more testing. Do I need to say we do not intend to EVER use the 3-ring again?
+
Fig. 1. Release shown with side plate removed.

KEEL
FRONT
HOSE CLAMP
1/8" Al BRACKET
1 1/4" MACH. SCREW
NYLOC
WASHERS
SPRING LOADED JAW
PULL LINE
LOCK
UP
CLOSE
OPEN
+
Joe Sztukowski
Des Moines, IA
*
1984/05-13

SKYTING IS A LONG TERM OBJECTIVE

Dear Donnell;

We began to tow with one of your bridles during October 1983. Initially we used a static line system but were unsatisfied with our ability to control line tension. The problems lay in a mechanical tension indicator.

Several people had accquired a reel a number of years prior which we began using in November. This device was very sensitive to pressure inputs on the brake so it took some time to develop a smooth technique. I have appreciated the use of a weak link in several situations, none of which were unique to the literature. I have also appreciated the "forgivingness" of the Skyting system.

Several of the individuals in our group are beginning to develop some skill on the reel and our flights are becoming smoother and more predictable. We have yet to tow anybody with less than a hang III. Our concentration for the next season will be on developing a group of qualified vechile and winch operators. There are, however, quite a number of hang III's to practice on so we won't be endangering our student base.

In terms of consistency and efficiency, the last of our 60 tows have been the best. Sunday, April 1, pilots in our group had two (2) 5,000' altitude gains with 1 hour flights. Surface winds were light and variable so the thermals were going almost straight up.

Yup, we're quite excited about the potential skyting has in our area. Like yourself, our foot launch sites are 2-5 hours away. Its' development, however, must be approached cautiously for it to grow consistantly and safely. This is, after all, our long term objective.

Up to this point we've found the information in SKYTING invaluable in our work and will continue to regard it closely.

Rod Regier
Prairie Wind Flight School
Winnipeg, Man.
CANADA
*
1984/05-14

PROGRESS IN ISRAEL

Dear Donnell,

The people in our association in Israel are starting to become interested in Skyting. One came up to my place to watch the system. Until now I'm the only pilot in Israel doing towing. There were many difficulties to do it alone, without anyone that can help with advice or good ideas. I hope now we'll study it much more and make it possible for many other pilots to tow here.

Heber Itzhak
ISRAEL
*
1984/05-15

INTEREST FROM WEST AUSTRALIA

Dear Donnell,

I got your address out of the Skysailor magazine.

I am very interested in Skyting as I live in an area which is basically flat semi desert - which goes for a lot of traveling to find something high enough to fly off.

Please enter my subscription to the Skyting Newsletter and send me all the back issues. I have enclosed an extra $10 for shipping them air mail. If this is too much, please don't worry about going to the hassel of returning the excess to me.

Raf Fynn
Carnarvon
WEST AUSTRALIA
*
1984/05-16

MINNESOTA UPDATE

Dear Donnell,

A short update. We still have ice on the lakes here in Minnesota. (April 5, 1984) One certain field west of Swan Lake, where we tow, lost all its snow cover and because of the solar inclination produces nice thermals - 4940 ft AGL for me, 4700 ft AGL for Don Ray of Aurora MN, and 4000 ft AGL for Gene Stone of Grand Rapids MN. We all towed up to 1400 ft and released from our 1800 ft rope. We worked up to our altitude from 1000 ft AGL. This happened Sunday, March 31.

On April 3, my wife Terry towed up to 1000 ft AGL on the ice at White Water Lake and had her first thermal altitude gain of 1000 ft to 2000 ft AGL. Her thermal apparently originated from a thick strand of dark pine trees.

Bill and Terry Cummings
Hoyt Lakes, MN
*
1984/05-17

SOME COMMENTS

Dear Donnell,

Your reports from Saskatchewan remind me of the Grandpa Jones monolog about the musicians who after many miles of travel didn't know where in the world they were; so they asked and to their bewilderment, were told, "You're in, Saskatoon, Saskatchewan."

Gerard Thevenot seems reminiscent of the cartoon personality "Smiling Jack" of the old aviation adventure illustrated serial.

Look forward to your technical analysis of the Thevenot aerotowing system.

With the development of all these towing systems I would expect that there will be some R and D on some prone of recumbent/recliner, mod pilot protective enclosure flairing units.

Edwin G. Sward
Worcester, Mass
*
1984/05-18

LOW COST TENSION GAUGE

Dear Donnell,

I just got my bridle and can't wait for some decent weather to get out and use it.

It seems from the newsletter that what is needed is an inexpensive hydraulic tension gauge. I have located some surplus cylinders that have a 1 1/4" bore with a 1/2" shaft, which gives an area of 1.03 square inches. I have built two gauges with these cylinders and the accuracy is better than 5%.

If anyone would like to get one of these cylinders they can send me U.S.$20.00 or CAN$25.00 and I'll ship them post paid. Or for U.S.$60.00 or CAN$70.00 I'll supply an assembled and tested gauge with 15 feet of hose and 0-300 pound gauge. Anyone interested can contact me directly.

Doug Keller
23 Taraglen Crt. N.E.
Calgary, Alberta
CANADA T3J 2G7
(403) 293-4008
*
*

1984/06
*
SKYTING NO.26
JUNE 1984
*
1984/06-01

Shoulder Towing and The French Connection

by Donnell Hewett

Now that center-of-mass towing is becoming the accepted mode of towing hang gliders, more and more interest and efforts are being channeled toward simplifying the design of the bridle system and to make it more convenient and more reliable. You have seen several examples of this in recent issues of SKYTING: the Lake bridles (No. 22), the threaded bridles (No. 23 & 25), the Thevenot-Skyline Aerotow System (No. 24). More than one of these designs accomplish the bridle simplification by attaching the towline directly to the pilot's harness - specifically to his shoulder straps. This article describes the theory behind this practice and explains why and how The French Connection helps improve the performance and safety of such designs.

THE CENTER OF MASS CRITERIA

The importance of center-of-mass towing was emphasized from the beginning of the skyting concept. SKYTING No. 1, in Part 3, clearly explains why center-of-mass towing is essential for safe towing. It also demonstrates why body towing is a closer approximation to CM towing than heart-bolt (keel) towing. In that article, however, it was assumed that the towline was attached directly to the center of mass of the pilot - i.e. to the pilot's tummy. The situation is slightly different when the attachment point is the pilot's shoulders. The force diagram for this situation is illustrated in Fig. 1 - namely, the pilot weighs 150 lbs, the glider weighs 50 lbs, the dashed glider reference line (control bar) is 4 ft, and the pilot-glider distance is 3 ft. We are also assuming that the pilot is held in the prone position by a line from the suspension point to his shoulders.)
+
Fig. 1. Shoulder Towing Force Diagrams

a. Take off.
b. Climb out.
c. Top out.
+
Figure 1a shows the forces during takeoff (or any other time that the tow force is essentially horizontal - such as when aerotowing). A comparison of this diagram with that for tummy towing (illustrated in Fig. 5b of SKYTING NO. 1) shows very little difference. Because we are towing from the shoulders instead of the waist and because everything is tilted upward by the towing force, the tow point (shoulders) has been raised a few inches higher than it was in SKYTING No. 1 (the pilot's waist). But as far as tilt angle, trim, and everything else are concerned, the result is essentially identical. During takeoff, the forward flight characteristics and performance of the hang glider is essentially the same for shoulder towing.

Of course, not everything is the same for shoulder towing as for tummy towing. The "pull" on the pilot is different and the transverse flight characteristics are different. For example, the shoulder "pull" essentially forces the pilot into prone position (even on takeoff) while the tummy "pull" lets him stay erect if he so chooses. And if the glider gets turned sideways, the transverse "pull" on shoulders causes the pilot's body both to rotate and shift sideways, rather than just shift sideways as in tummy towing.

So what is the bottom line? During takeoff, shoulder towing, like waist towing, results in a nose-up tendency for the glider with the control bar trim position about 3 or 4 inches behind the normal free-flight trim position. The thrust line of the towline is below the center of mass of the glider-pilot system (about 5 or 6 inches, i.e. about half that resulting from tummy towing), so that a sudden increase in towline tension can cause the glider to pitch up violently. Obviously this is not an ideal situatioin, but it is significantly better than the old base tube method of towing.

Well, so much for takeoff. What about the forces during climb-out? Are they the same as or are they different from those encountered during takeoff? Figure 1b gives the answer. By the time the glider has reached a 30 degree tow angle, the trim position of the control bar has shifted back to the normal trim position. No longer is the pilot flying with his hands back toward his waist, they are now in the normal, chest high position. In other words, during climb out, shoulder towing is very much like true center-of-mass towing. This is great!

Notice that I said, "very much like," and not "the same as" in the preceeding paragraph. There ARE differences. One significant difference is the fact that the thrust line of the towing force has shifted from below the pilot-glider center of mass to above the system's center of mass. This means that a sudden increase in towline tension, instead of causing a pitch up tendency, will now cause a pitch DOWN tendency! Obviously, somewhere between takeoff and the 30 degree towing angle the conditions are just right for NO pitch tendency. Hey, this is great! What angle would that be? Say, 15 degrees? That's just right for the early, critical climb out situation!

But alas, the situation is more complex than this. It turns out that the proper towing angle for the towline thrust to pass through the system center of mass depends upon the tension itself. So a sudden change in towline tension ALWAYS has some kind of effect upon the glider trim and pitching tendencies. In other words - and you would do well never to forget this fact - SHOULDER TOWING IS NOT CENTER-OF-MASS TOWING!

Figure 1c illustrates this quite clearly. Here the glider is topping out and the towline tension has been increased from the previous 50 lbs to a more realistic 100 lbs (1/2 g). Remembering that the drawing was made for the equilibrium (steady flight) condition and not for the more dramatic dynamic (suddenly changing) situation, one can begin to realize how much shoulder towing can deviate from center-of-mass towing. When topping out at 60 degrees under a 100 lb tension, the trim position of the control bar has moved 9 inches forward of the normal position (and a full foot from the original takeoff position). Furthermore, the thrust line of the towing force is 18 inches in front of the system's center of mass. (And under a weak link break condition the situation would be even worse.)

Imagine what would happen if the weak link suddenly broke. The 150 ft-lb nose down towing torque would immediately go to zero. As far as flight characteristics are concerned, the situation would be the same as if a pilot in free flight suddenly experienced in a 150 ft-lb nose up torque. Before the pilot could react, the glider's nose would pitch up violently, possibly causing a whip stall with the resulting tuck and tumble. NOT GOOD!

Notice also that we've been assuming that the pilots harness has a rope between his shoulders from being pulled downward out of the normal prone position. Imagine what would happen here without such a limiter. He would have a 100 lb force pulling him down to into - or possibly through - the control bar. If you don't like flying your hang glider with your body upside down and through the control bar, I suggest that you use a prone limiting line when you shoulder tow!

THE DANGERS OF BODY TOWING

From the above discussion I think you can see that there are certain dangers associated with shoulder towing which are, in general, different from those of tummy towing. But both shoulder towing and tummy towing are forms of body towing, and as such they are expected to have certain characteristics in common. Undoubtedly some of the known dangers of body towing will also plague shoulder towing, so it seems wise to review some or the known body towing dangers.

In my opinion, the greatest danger of body towing is the pitch-up tendency which occurs under certain conditions, particularly during takeoff. At least one pilot has been killed because of this pitch-up tendency (see SKYTING No. 19). Several other pilots have narrowly missed death when the top release of a skyting bridle released and the bottom release remained attached to the pilot's body. Although not intending to "tummy tow" these pilots suddenly found themselves doing so - and with catastrophic results.

The common scenario is as follows: There is a sudden increase in the towline force on the body of the pilot. Since this force occurs below the center of mass of the pilot-glider system, there is a corresponding sudden pitch-up tendency on the glider. As the glider climbs into a whip stall attitude, the pilot tries to pull the nose down by thrusting his body forward. Meanwhile the forces are building up so great that the weak link (or something else if there is no weak link) breaks. The glider is now motionless, in free flight, with its nose pointed almost straight up. As the glider starts sliding backwards through the air, the forces cause the nose to drop rapidly and the glider goes into a tuck. Frequently the nose down rotation of the glider is so violent that it passes the vertically downward position, turns upside down, and begins tumbling. The pilot usually slams into the glider's structural members breaking one or more of its tubes. Even if the pilot is still conscious and has a parachute, it is difficult for him to deploy it because of the tumbling and spinning of the glider. Depending upon the altitude and other conditions, the broken glider either slams into the ground or spins into the ground like a maple leaf. Usually the pilot is either killed or seriously injured.

Although the above scenario has never been reported for a shoulder towing pilot and although it is unlikely to occur under normal shoulder towing conditions (considering the force analysis just completed in the previous section), there is still the possibility that it COULD happen. You should be aware of this fact should you decide to shoulder tow.

In fact, not only have I received no shoulder towing accident reports of the above type, I have received no shoulder towing accident reports of any kind. Either shoulder towing is rare, its accidents are rare, or the reporting of its accidents is rare. But even if shoulder towing is really safe, it appears to me that there are certain potential dangers associated with it - dangers beyond those normally associated with true center-of-mass skyting. Most of these potential dangers are a result of violating Skyting Criterion No. 5 - the slow transitions requirement. (See SKYTING No. 3.)

Besides the dangers already mentioned, imagine what would happen if a shoulder towing pilot is not quite ready at takeoff when the vehicle starts. (It can happen, folks!) Since the towline is attached above the pilot's center of mass, there is a good chance he will be pulled off balance through the control bar, falling nose down into the ground just before the glider does the same.

If the towline passes THROUGH the control bar to his shoulders, the pilot can run into control problems when the glider gets high or if a gust of wind forces the nose down and he tries to push the control bar out beyond his shoulders.

If the towline passes UNDER the control bar, the pilot can have control problems on takeoff or during early climb-out. In fact, this last condition could be fatal. If you think the towline pushes up on the control bar when using a normal skyting bridle with only 2/3 of the towing force attached to the pilot's waist during takeoff, imagine the effect when 100% of the towing force is pulling up from the pilot's shoulders. I doubt that even an experienced Hang 5 pilot could safely foot launch with the system rigged like this. And even if he could get airborne, he would not be able to pull the base tube any lower than his shoulder height. In essence he would have little or no control of the glider either on takeoff or during early flight.

SUCCESSFUL SHOULDER TOWING SCHEMES

From the above discussion of the dangers and potential problems associated with shoulder towing, it would appear that shoulder towing is totally impractical. But don't underestimate the ingenuity of creative individuals. As the saying goes, "Where there's a will, there's a way."

There are at least two successful shoulder towing systems which have been reported so far in the literature. Mike Lake, of Norwich, England, describes a shoulder towing system in SKYTING No. 22, which solves the problems associated with towline interference by passing the towline over and under the control bar in such a manner that it behaves like it is over when it needs to be over and like it is under when it needs to be under. And Gerard Thevenot, of France, introduced a shoulder towing system to the U.S.A. as one of the components of the Skyline Aerotow System (see SKYTING No. 24) which passed the towline through the control bar and utilizes a French Connection as part of the glider control system (more about this later).

Of the two systems, Thevenot's has received the widest publicity and the largest amount of testing - even to the point of commercialization. All the reports indicate that the system is proven and extremely forgiving. But Lake's design holds the greatest potential for surface (land or water) towing. This is because Thevenot's bridle is simply one component of a complete system - an air towing system. When air towing, the towline angle remains forever essentially horizontal, so there is never any tendency for the towline to interfere with the control bar's movement. But if this bridle were used in land towing, as the towing angle increased, many of the problems mentioned above would occur.

The Lake bridle, on the other hand, solves most of the problems associated with varying tow angles (but not all). It eliminates the control bar interference problems, but not the control problems due to the non-center-of-mass characteristic of shoulder towing. What the Lake bridle needs, in my opinion, is the French Connection.

THE FRENCH CONNECTION

The French Connection is a mechanical device which is inserted between the pilot's hang point and his harness. It is illustrated in Figure 2 and operates as follows:
+
Fig. 2. The French Connection
+
a. Rear limit.
Normal Hang Point
Keel
Hang Point
+
b. Forward limit.
Keel
Hang Point
+
The unit is attached to the keel of the hang glider and adjusted so that when in level flight the pilot can move forward or backward within the limits imposed by the size of the device. Outside these limits the pilot's point of suspension remains fixed and he swings back and forth essentially the same as when suspended normally. But inside these limits the point of suspension moves with the pilot. Instead of having to swing in an arc and having to raise his center of gravity, the pilot can move back and forth with essentially no effort. In effect, the device allows the pilot to effortlessly retrim his glider to any desired flight speed (within the limits of the device). From the pilot's point of view, the French Connection acts much like "power steering" and allows him the same control of his glider with much less effort than normal - or more control with the same effort.

Now you can see why the French Connection is highly recommended for shoulder towing. Since shoulder towing is NOT center-of-mass towing, one needs the extra control afforded by the French Connection to regain the control that was lost. For example, suppose the pilot is flying in trim for a certain speed when suddenly the tension increases. The pilot is immediately pulled forward and without the French Connection the glider would certainly tend to pitch up. But with the French Connection, the pilot's suspension point also moves forward. This tries to make the glider pitch down and speed up. As a result, the pitch up and pitch down tendencies essentially cancel one another and the pilot simply finds himself flying faster with the glider still in trim but with his body farther forward.

The effect of a sudden decrease in towline tension (weak link break), a changing tow angle, or a changing air speed (wind gust) produces a similar result - namely, to a large extent the French Connection allows the system to be self-correcting.

I say, "allows" instead of "makes" because an inexperienced pilot can cancel out this self-correcting tendency. For example, in the above illustration, if the pilot holds on to the control bar and does not allow himself to be pulled forward by the increasing towline tension, then his trim position will never move, and the glider will pitch up the same as if no French Connection were present.

We have not discussed the "double" French Connection, where the pilot not only moves freely back and forth but also from side to side. But the result is essentially the same: more control for the same amount of effort and a tendency toward self-correcting the problems associated with towline variations.

PUTTING IT ALL TOGETHER

In conclusion, I would like to say that body towing - particularly shoulder towing - has a promising future not only in aerotowing but also in surface towing. Although it is not nearly as close to center-of-mass towing as standard skyting, with proper precautions it appears to be a viable alternative to true center-of-mass towing. At least two shoulder towing systems are in operation today and each seems to be adequate in its own particular environment.

But when I get around to trying shoulder towing, I plan to combine elements of both of these systems. Specifically, I plan to use the Lake bridle along with a French Connection. But since it is going to be some time before I am able to try out this system, do not expect a first hand report of its performance any time soon.

As of now, I do not know of anyone else who is using this combination or who is planning to use it; so if you know of someone, please keep us informed. And if you decide to evaluate the system yourself, let us know how it performs and whether or not you like it.
*
QUESTIONS AND ANSWERS
*
1984/06-02

Dear Donnell,

I have some questions. First of all, since I have not seen, read, or heard about supine pilots skyting, does this type of suspension system create and unconquerable problems for takeoff? I witnessed a takeoff of a gung ho pilot in a cocoon harness. Fortunately he had flying speed when he fell so he flew out of it. That's not my idea of a good technique and maybe cocoon harnesses don't work so well for this.

Secondly, in areas where a mile or more of clear towing area is hard to find, how about the reverse pulley setup sailplanes have used. With the tow vehicle driving toward the pilot the room necessary should be significantly reduced. Do you have any comments on this form of towing?

Lastly, if I were to launch out of the water from my lake, would the drag exceed the 1 G weak link?

Mike Nelson
Union, MI
*
1984/06-03

Dear Mike,

Information on most of your questions is found in various back issues of SKYTING. Here are some more comments:

(1) Supine skyting has been done, although I personally know of only one pilot who has done it. He no longer subscribes to the Newsletter and I am not sure what his current activities are. I do not recall exactly how he hooked the body line to himself so you should contact him yourself, he is: Mike Haly, 5211 94'th, Lubbock, TX 79424. Ph. 806/745-4589.

As far as control is concerned, no, this type of suspension system does not create any significant problems on take-off or while flying. And as far as cocoon harnesses are concerned, I do not know exactly how others do it safely. But there are a lot of pilots out there skyting with cocoon harnesses, so I am sure there is a way.

(2) The main advantage of using a pulley and driving the tow vehicle toward the glider is not so much to save room or gain higher altitudes as it is to reduce turn-around time. In fact, the same altitude will be reached using this method as can be attained with a "static line" tow. (Here I am assuming the same DRIVING distance, which does not include the stretched out towline. I.e. the towline is stretched out in (and the glider takes off from) the open field beyond the end of the runway. If no open field exists, then, yes, you could get 25% higher with the pulley set up in no wind conditions, and maybe even higher in stronger winds.) But, whereas the "static line" must be brought back and lined up for a new take-off, the pulley system is already lined up at the end of the flight.

The main disadvantage of this method is that it requires more towline to reach the same altitude. There is also the possibility that there is more wear on the towline as it is drug along the ground under tension instead of being completely lifted into the sky during the towed flight.

(3) Yes, the drag of a deep water tow launch is greater than 1 g. Some pilots solve this problem by using a payout winch and launching with the leader of the bridle. Once the pilot is airborne, the rest of the towline (including the weak link) is fed out. If you do not have a payout winch, you may have to devise another way. (For example, I have suggested that one use two releases on the boat, with the weak link between them. Once the pilot is airborne, the first release can be tripped, placing the weak link on line at the bottom of the towline.) And finally - although I do not recommend it - some pilots consider the added safety of water towing adequate to forego the luxury of a weak link - especially if an experienced spotter and a reliable safety release are used.

Let me know how things go with you and if you have any other questions I may be able to answer.

Donnell
*
1984/06-04

1983 TOWING FATALITIES

by USHGA Accident Review Chairman Doug Hildreth (excerpt from HANG GLIDING, April 1984)

Towing: Let me make one thing perfectly clear: I think that towing is great. I am NOT out to give towing a bad name and I know that it will grow and prosper. Nonetheless, at this moment, the "towing movement" is slightly removed from the free-flying contingency, and I receive very few towing reports. I hope that this will change as towing matures, as the USHGA supports towing, and as the tow pilot and foot-launch pilot intermingle.

I am impressed that the increase in legitimate towing activity over the past year has occurred without fatality. There were three towing deaths and those reports were extremely sketchy. As best I can tell, all three were inexperienced pilots automobile towing and were "on the fringes." In free-flying, tandem and tow, there have always been "fringe pilots" who are out of the mainstream and who ignore standard information and recommendations. Although we must count these three as towing fatalities, they do not represent state-of-the-art towing activity.

There has also been concern expressed that if a pilot tows to a thousand feet, releases, flies a hundred miles and crashes on landing, it should not be categorized as a towing accident, since the towing had nothing to do with the accident.

On the other hand, I do not think it belongs in the foot-launch category either. Maybe crashes on launch should be categorized either in foot-launch or tow and, once the pilot has launched/released, then the third category be established. It sounds pretty complicated to me, but give me your imput.
+
1983/05/17
Dennis Guessford
27
Adams, NY
Injuries unknown.

Auto towing.
+
1983/06/15
Johnnie Gayler
29
Vigo Park, TX
Chest, head, pelvis, brain death.

Auto towing.
+
1983/09/00
Mark Morgan
00
Kane, PA
Injuries unknown.

Auto towing.
*
SEVERAL NEW THINGS AT ONCE
*
1984/06-05

Dear Donnell and Helen,

I know that you are concerned about each one of your fledglings (Will and Sara came to Kingsville for some skyting training last year.) but after I could use my arm again I was too embarrassed to write.

Oh, it didn't break, I just pulled the shoulder out of joint. That was the second try. My first attempt won me a bloody nose.

You see, I ignored your prime rules of common sense and tried several new things at once. Let's see, there was a new winch, a thousand feet of stretchy line, an unmowed rough field, an untested (too tough) weak link, and my own stubborn attitude.

You can imagine it - the line stretches, I brace, more stretch, more bracing, wing drops, I'm out of balance but can't hold back any more, off we spin, tips in the brush. Weak link didn't break and I did a stagecoach drag that wasn't fun but I did it again; that was even less fun.

Now that I'm recovered and the weather is warming up, I want to try it again. Carefully.

Reading Skyting is a definite lift, and I enjoy reading them.

I will write again with better news.

Will Wyckoff
Greenville, MI

P.S. Hope this time he doesn't dislocate his shoulder. This time I will try & keep my eye on him, unless he tries it when I'm at work.

Sara
*
1984/06-06

Dear Will and Sara,

I know it takes courage to share embarrassing experiences with others, but this is the only way I know to impress upon others the importance of following certain safety practices. And by admitting that we are all human, we help break down barriers to the open communication. Thanks for being so candid. I hope others will follow your example.

Donnell
*
1984/06-07

COMMENTS ON SAFETY

Dear Donnell;

After having read all your issues and completed some 40 tow flights there are some comments I would like to make that will provide all skyting pilots with food for thought.

1. Two release bridles (which remain connected to the tow-line after release) are potential killers. There have been documented cases of bridles tangling around the necks, base bars, side wire; upper releases hitting pilots in the head; premature upper release causing whipstall close to the ground; premature lower release causing kite to tumble twice and break up. This seemingly endless list of accidents could have all been avoided by using the single point release bridle. Carrying the bridle in flight is a small price to pay for the safety benefit. (Also, if you use pre-stretched yachting rope, there is no need for the 100' leader - another safety improvement.

2. The Donnell Hewett bridle is probably the best thing that has happened to Hang-gliding since the development of the cocoon harness. As good as it is, it has a minor fault in that during the first 50-100 feet of height gain, the angle of attack of the kite is at its greatest. It is during this stage that a thermal induced weak link failure could be dangerous. (On tow, under relatively constant pressure I have recorded 1500+ feet per minute up and 600 feet per minute down within a short space of time on the same tow.) To minimize this risk, my friends and I control the pitch for the first 50-100', by not letting the bridle have complete control of the kite until we are safely away.

3. For those of you who are competent SKYTERS and whose take off roads or runways have trees that the driver has the greatest difficulty extracting 2000' of rope from, try "laying off" during crosswind take offs. Glider ((sailplane)) pilots do it all the time - just put on a little roll into the wind and fly straight up the strip.

Learn it cautiously and you can be sure of keeping your drivers longer.

Good flying,

Lex Jones
Allanson, W. Australia
*
CB-VOX NOW AVAILABLE
*
1984/06-08

Dear Donnell,

I hope this letter finds you well. When we talked last, fall '83, I mentioned putting together an article on our deep water towing. Well, I got side tracked on another project which left me with no time to write.

I have spent most of my free time this winter designing and building a CB-VOX. The unit voice activates the Radio Shack 5-watt hand held CB transceiver. I got spoiled using a voice activated FM radio which we had to give up because of its limited range. When we decided to go with CB's, a VOX (mine), several pilots requested I build a unit for them and eventually convinced me that I should market the unit. I don't know what your policy is on presenting such material in SKYTING, but I think the CB-VOX would be the nuts for towing communications.

The VOX unit eliminates the need to operate a push-to-talk button. Simply speak into a microphone connected to the input of the vox unit and the CB is instantly switched from receive to transmit. A microphone is connected to the VOX using a standard miniature phone plug. The microphone's signal is carried to the output of the VOX to the external mic-jack of the CB by a 5 DIN patch cord provided with the unit. Add a set of earphones plugged into the external speaker jack of the radio, and a headset configuration is completed. Directions for a headset hookup are included with the unit.

The voice-activated operation of the CB radio permits a pilot to fly with full hands on control whether scratching in ridge lift, coring a thermal, riding a tow, or just crusing in smooth air. "Speak and you shall transmit;" it's that easy.

The VOX unit is compact and lightweight. It fits conveniently on the left side of the CB radio and does not interfere with any of the radio's standard features. Power for the VOX is provided by a single, externally mounted, 9-volt battery. A dual battery switch is used on the unit allowing for a second, internally housed, reserve battery. Also featured are a mic-sensitivity control, and a low battery indicator.

In flight testing has demonstrated the unit's ability to provide convenient, effective, and dependable VOX operation.

The VOX unit is priced at $115 and carries a one-year warranty.

Can you help me get the word out?

We are looking forward to another boat towing season which will start soon. I'll keep you informed. I think we will try the threaded bridle - it looks good for deep water applications.

Don Boardman
6433 Karlen Rd.
Rome, NY 13440
*
1984/06-09

Dear Don,

Now that commercial skyting products are becoming available, we have adopted the following policy: New product announcements and product evaluation reports (which are considered to be newsworthy) are edited like any other skyting material and published free of charge for the benefit of the readers of SKYTING. Advertisements of commercial products and repeated product announcements are published at a rate of U.S. $5.00 per published column inch. (Since the publisher reduces the copy by 0.76 then one column inch corresponds to a rectangle 1.3" high and 3.3" wide before reduction.)

Donnell
*
1984/06-10

TOW GAUGE DEVELOPMENT

Dear Donnell,

Thank you very much for showing interest in my tow gauge. Since I received your letter, much has happened. To begin with, my gauge worked flawlessly until I tried to use it during some -20c weather this winter.

As you recall, this is the unit I made from an old shock absorber. Because of the problems I had, I would rather not get into the lengthy description of manufacturing one.

I will, however, give you a rough idea of how I made mine in case people out there would like to pursue this theme. I started with an abandoned shock absorber, and cut the outside case off of it. Next I disassembled the insides of the inner cylinder. I found the I.D. of this to be 1 3/8", so I purchased a rubber piston of the same physical size (from a master brake cylinder of a car). I had to punch a hole in the center to fasten it to the rod that travels up and down inside the cylinder.

Next I bought a seal that would stop the fluid from leaking out from the bottom (where the rod slides up and down) and machined it into place. The rod also had to have a ring welded to it to fasten the tow rope. Last, the whole thing was assembled.

Oops, forgot to say somewhere along the line a hole must be drilled near the bottom of the cylinder to accept the line that runs to the pressure gauge. Also there should be a ring at the top of the cylinder to tie it to the vehicle. Last, but not least, the unit should be filled with a fluid compatable with the seals.

The problem I had with mine this winter was my own fault. I failed to back that lovely new piston with a smooth surface, and as a result, the piston cracked!!!

I have rebuilt my original cylinder and it appears to work smoothly again but I have not had a lot of time to test it. Once I am assured it will function as I want it to I will write a more comprehensive guide to building this unit.

I also warn anybody using this system, this is one gauge that should be used with the respect it deserves: EXPERIMENTAL!!!!

Another word for the wise, when I had the pleasure of finding my gauge faulty, it had leaked hydraulic fluid (quite profusely). I was lucky enough to have wraped my unit in plastic, prior to the incident. I be this fluid would have done much dammage to my flight gear had it not been contained.

Don Baker
Kamloops, B.C.
CANADA
*
1984/06-11

REMINDER

Don't forget that I will be working here in Colorado through the middle of August. So if you want to speed up your communication, address your letters to Donnell Hewett, 1274 Hwy. 72, Golden, CO 80403. Phone: 303/642-3265.
*
*

1984/07
*
SKYTING NO.27
JULY 1984
*
1984/07-01

TWO DAYS OF SKYTING

Dear Donnell,

I recently received all back issues of Skyting (through No.24) and devoured the information with much interest. Having very little knowledge of the Skyting system, it was very interesting seeing Skyting develop thru the years and learn of all the trials and tribulations in a few days time.

Here is a rundown of our first two towing days:

Saturday, June 9th - Two of the five (five partners own a winch together) are touring the U.S. and are presently in California. I and another partner showed up and hooked up the gear to my Comet. We basically just added a third hang loop with a ring attached for a three ring release system. The weather was 95 degrees and sweat was dripping down from everyone but I talked five local pilots into doing a people tow. Somehow, I got airborn for 5 to 10 seconds and tried to release. Actually, it released accidentally when I went from downtube to basetube and I glided in on the wheels. We tried three more tows to varying degrees of success but my partner, Jeff, twisted his ankle on the fourth tow. Many other pilots were not only hot but very hot to try a people tow. However, I was late for an appointment and had to leave. It wasn't much but it gave me the confidence I needed for my first winch tow the following day.

Sunday, June 10th - Jeff couldn't tow because of his twisted ankle but he showed up for moral support and winch operator training. John also showed up and we flipped to see who would go first. I won the toss amd decided to tow first. We had to learn to skyte on one end and turn the winch on the same flight.

The winch is a drum with 3000 ft of polypropylene rope reeled in by a 650 Yamaha engine with a slip clutch in the drive shaft to limit tension. The day went like this:

First tow: John on the winch, Fred (that's me) on tow.

I had a walkie talkie with a boom mike locked on transmit. I gave the go and heard the winch reving up in first gear 2000 ft away. Suddenly I was running and in three easy steps was airborne with a grin on my face. Then the stretch in the line accelerated me forward and all of a sudden I outflew the tow rope and had thirty feet of line behind me. Fearing the shock I would encounter when the winch took up the slack (I forgot I had a weak link to protect me), I released under no tension, and flew along with the bridle until the winch caught up and pulled off the 3 rings. It was a smooth take-off, 40 ft flight, 10 feet off ground, and a good landing. I wanted more.

Second tow: John on winch, Fred on tow.

We decided first gear was too slow and opted to try second this time. I held back too long and broke the weak link.

Third tow: John on winch, Fred on tow.

I decided to start my run as soon as I felt a tug on my harness. Four steps and I was off like grease. Again, I overflew the line but not as dramatically as before. I decided to hang on and wait for the take-up. My wheels were about 6 ft off the ground when the slack took up and I began climbing smoothly. At 30 ft above the ground, the top auto-release let go. (I didn't have a bottom auto-release even though I knew of the idea.) The glider began bucking and just as I decided I better release my body release, the bridle fell away and I glided to earth wondering how the release let go without me pulling the pin.

To my surprise, the three ring release was still dangling on my harness.

It took me fifteen minutes to figure out what had happened. In effect, I had a threaded bridle, the top three ring release went out through the apex ring, back through the Carabeiner that held the body 3-ring release and smacked me on the thigh as a reminder before letting me go.

The bucking was from the one, two, three of release - first ring, second ring and slap. I was quite surprised that it happened and was glad because I wouldn't want to be towing from body only at 30 ft.

Fourth flight - John on winch, Fred on tow.

After lengthening the auto-release, I had another effortless take off. Again, the wait for the slack rope then climbed to maybe 200 ft and released. I did my first 360 degree turn at that training hill after six years of flying there and landed smoothly.

Fifth flight - this time I ran the winch and John towed.

I started the winch, put it in gear and held in the clutch waiting for the "go" from John. When I got it, I let out the clutch at an idle until I saw John running, then slowly accelerated until he was airborne at which point I gunned the engine to try to prevent him from slowly overflying the rope. He flew to 30 or 40 ft high, then pitched down and began descending. I thought he was just trying not to get too high and kept pulling. (He did not wear the boom mike.) By the time he got to twenty feet and was still descending, I decided something was wrong and disengaged the clutch. He glided in and landed smoothly.

When I walked over to see what happened, he said he released the body release but the auto-release didn't let go. Upon checking, we found it had released but John had put the three-ring release facing back and down which still should have worked but a slight bump on the ring where it was welded prevented the second ring from going through the first.

(WARNING - Buy high quality rings or file down the welds when using 3-ring releases.)

Sixth flight - John went back for one more, launched smoothly, then turned to 45 degrees off track. I let up on the throttle and he brought it around. I then goosed it again. He went up to 50-60 ft, then released and landed. The heat was getting to us so we packed it up and went swimming.

After our first day, we were both very excited and ready for more and higher flights. The smoother acceleration on the winch prevented the rope from going slack. I have decided to try a regular threaded release instead of the kind of bumps, and picked up a sheet stopper tonight. I was wondering how to mount it when I read Skyting #25 and saw Joe Sztukowski's illustration. I think I'll do it that way.

Your newsletter is great and well worth the money. Enclosed is $10.00 for future issues.

Frederick E. Mack, Jr.
Pottstown, PA
*
1984/07-02

MORE ABOUT THE THREADED-BRIDLE RELEASE

Dear Donnell,

I am writing this as a supplement to my last letter about the threaded bridle release.

Two malfunctions are possible if the skyting line is just attached to the keel ring with a pull-pin release because the pull pin (threadless eyebolt) must ALWAYS point parallel to the directions of the pull. The first possible malfunction is that the keel ring will twist somewhat under tension. The second is that, as the glider ascends, the rope knot slips down the keel ring so that the pull pin is facing the rear of the glider. (See Fig. 1, Page 4, SKYTING No. 25.)

Under the modified system (see Fig. 2) neither of these problems can take place. Also, the bridle rope is out of the way of the pilot's head. Please note that since the rope end does not pass through the keel eyebolt or U bolt, a tangle is virtually impossible. Also, no matter how much line tension or tow rope angle there is, the pull pin always points parallel to the direction of pull. As with the last system, the wind pressure tends to straighten the rope out after release as it heads for the apex ring.

I have bolted the keel eye bolt and U bolt to my trainers, but I am sure one can find an easy method to hose clamp them on to a glider which would be used for towing only part of the time.
+
Fig. 2. Modified Threaded-Bridle Release

5/16" KEEL EYEBOLT
5/16" x 2" U-BOLT THROUGH CONTROL BAR
PULL PIN EYEBOLT
(THREADS CUT OFF)

Doug Gordon
Tempe, AZ
*
1984/07-03

COLORADO AND PODS

Dear Donnell,

Approaching Denver across the prairies from the east by train, we could faintly see the Rock Mountains in the distance. Gradually they loomed on the horizon as a huge great bluish wave, and finally we were in Denver at about dusk. Getting into the high country west of Denver after dark - with some moonlight as I recall - tall Colorado evergreens could be seen outlined against steep slopes which in daylight must have been fabulous scenic vistas. In retrospect, everywhere along the high iron, we could see many places that might have been suitable for foot launch glider launch sites.

In a communication from Golden Sky Sails 8/28/79, someone whose signature I can't decipher, suggested that I forward my ideas (safety pods) etc. to United States Hang Gliding Magazine in the form of Letter to Editor.

In Dec. 1982, I received a brochure from Cyclodynamics of Colorado, Inc., 6367 Arapahoe Avenue, Boulder, Colorado 80301, about a Cyclodyne Human Powered Vehicle with fairing of lightweight fiberglass and vents for practical air circulation, etc.

For those interested in pilot protective fairings, I would suggest that for ideas they should join the International Human Powered Vehicle Association, P.O. Box 2067, Seal Beach, California 90740.

Also a pedal-powered center of mass tow launch system might possibly be developed.

As they say at Golden Sky Sails: Good Air!
Edwin G Sward
Worcester, Mass.
*
MOVING - BUT STILL INTERESTED
*
1984/07-04

Dear Donnell,

My auto-towing days are limited as I am moving to Atlanta and will be close to the mountains (Chattanooga) but I still want to keep up with the towing information as I feel this is VERY important.

I am interested in winch and aerotowing and would like to see plans for a SAFE home-built winch. Have you any knowledge of this?

Good lift and tight lines to you.

Cal W. Tax
Miami, FL
*
1984/07-05

Dear Cal,

No, I don't. How about it out there, do any of you have plans for a SAFE home-built winch? If so, how about sharing them with us.

Donnell
*
1984/07-06

SKYTING IN ENGLAND

Dear Donnell,

Many thanks for the continuous high quality of the Skyting Newsletter. Rona and I have just completed an exhausting 4 months of activity. At present we are grounded due to poor wet conditions, which affects our winch badly; however, it does give us a little breathing space for writing to you and doing all the things that keep getting put back because of flying. There is much to tell; so I will be as brief as possible.

During the 12 weeks of cold and dry, the East of England has enjoyed 10 week ends of flying weather. The inevitable fiddling about with new equipment has slowed actual flying time, but the systems are now beginning to pay dividends. A normal 5-hour session produces a dozen flights shared between three of us. It also includes traveling to the old airfield, the setting up of the equipment and, finally, returning home. Over the period we have completed lots of maneuvers including short cross countries. We lack experience in cross countries but with the onset of summer this will change.

One of our team members is building a new winch of greater sophistication which will give us a wider range of weather conditions to fly in. We have experienced skyting on the line, which I must say is a wonderful experience. With the payout winch we also get bonuses height whilst kiting. We actually continue to go up! Rona is flying now very well indeed except she is held back due to lack of funds available to buy a small kite for her; however, this will be put to rights very soon.

I will have some comments to make on the call from Ted Gilmore in Skyting No. 24. He said that to retie the long weak link cord after breaking saves time, but it also reduces the effective strength of the cord due to strain loading. I am sure Ted realizes this, but I feel it should be commented upon to save others (not so wise) problems that may arise from weakened link breaks. I agree little pieces of cord are a messy thing to carry, but it's well worth using new ones.

The use of the threaded bridle fascinated me immensely, but I had reservations about that release above my head and all that cord whipping about on release. The biggest concern is releasing while the glider is turned. As the line shakes away there is a chance of it looping around the corner of the "A" frame, a nightmare experience I do not wish to experience. The use of the perlon is very sound. I have experimented with it and like the threaded action very much; however, I still prefer to have metal rings for the threading parts. I do not feel a danger there. In my view, the easier the line goes away the better.

Also if you refer to Skyting No. 22, Mike Lakes stepup bridle, you will see we use a release mechanism that is away in front of the glider and pilot. I like this very much. It's in view, clean and tidy. The bungie retracts it away from the pilot after release, and it's no trouble. As an advancement to the threader I prefer this to solve some of the problems. (See diagram.)

The release leg, as I call it, is operated as per diagram and releases the short perlon line which shakes away in front of the pilot and glider. The use of the umbilical-cord extension from the body also helps to shorten the length of the threader. If the threader does snag, the safety body back-up release is very useful. Making the leg is a little time consuming, but with patience is is not difficult or expensive.

Tony and Rona Webb
Leicester, England

P.S. This last week end we flew on yet another site. Ground in Norfolk is a little precious so we are having to negotiate a variety of sites to be used sparingly.

I flew for the first time a kite called the GYR, made in the north of England. All I can say is that once properly rigged tow wise it was super on the line - hands off position and a steady climb to a cool 1200 ft. The most amazing thing was the glider angle and overall length of flight I had. I did use a small thermal but only for a short time. The flight was in excess of 10 minutes with plenty of time for maneuvers.

T. & R. W.
+
LEZAIR'S ((LEJAIR) SHORT THREADER
+
Ring rooped to main hang straps on harness.
Threader attached to tow line ring.
Line with ring attached.
Loop
Quick release.
+
Nose
Keel Pocket
Bowden cable release
Release line
Rubber tensioner
Elastic bungee retract to nose
Bowden Release Line
Release cord held in hand.
+
Harness
Main hang strap on harness
Back up Release manually operate in emergency.
Note length Umbillical cord tied to ring and foltan release
Ring for threader
Threader
*
1984/07-07

SKYTING HIGH - AND DOING IT RIGHT!

Dear Donnell,

I haven't skyted personally as of yet; however, I know of a group that has had great success.

My brother (Marty) and Gary Evans, owner of Midwest Glider Supplies, skyte every weekend. By the way, they follow all eight skyting criteria!

On the weekend of June 2 & 3 one hang glider pilot who has limited experience (about 1 year) had a 6000' altitude gain above a 2000' tow. To top that, Gary flew about 40 miles getting as high as 6700' ATO and was limited by the large controlled air space around O'Hare Field (Chicago). He felt he could have made 100 miles easily.

Regarding the skyting gear from Midwest Supplies - all I can say is that Gary is one of those rare people who isn't satisfied with less than near perfection. He has won an award at the EAA fly-in at Oshkosh for his ultralight.

Enclosed are pictures of his gear that I think you will agree are top notch. Compare his prices with other gear on the market I find he is very competitive.

I hope this info is useful.

L.D. Bunner
Byron, IL
*
1984/07-08

THE FIRST SKYTING CATALOG

by Donnell Hewett

BACKGROUND

Since the material L. D. Bunner sent me appeared to be a copy of the Midwest Motorglider Supplies Catalog (although the word "catalog" was not mentioned), I decided to order my own copy of the catalog to be sure. Yes, they were the same - except that my copy contained some additional entries. This indicates that Gary Evans and Co. are continually upgrading and adding new equipment as it becomes available. This is a good sign.

In fact, I consider the catalog, itself, to be a good sign. As far as I know, this is the first skyting catalog in existence and, to me, a milestone in skyting development. It shows that skyting is finally reaching the stage where significant commercial equipment is available from a single supplier. I am sure it will not be the last such catalog, but it is the first, and as such deserves a review in this publication.

But before reviewing the catalog, itself, let my share the letter I received from Gary when I wrote and asked if I could review his catalog:
+
Dear Mr. Hewett,

At your request I have enclosed a catalog for you to use as you wish.

My primary occupation is with a large pharmaceutical company and the hang gliding business is to help support my flying habit. I am an advanced pilot, observer, and special observer. I sell hang gliders and towing components to experienced pilots. I am not into teaching beginners because of the hassle and liability. We do, however, extend an invitation for pilots to come and tow with us as long as the timing is compatible.

We are towing with 3000 feet of rope on a 2 1/2 mile park road and getting 2000 to 2500 feet. My longest flight to date was 40 miles which would have been much longer except Chicago's O'Hare International Airport got in the way. Given the right conditions, I believe our cross country potential is as good as anywhere in the U.S.

Although the manufacturers don't seem to be aware of it yet, I believe that land towing will be a major factor in hang gliding's future. A good deal of the credit for this is yours. Had it not been for your innovations and persistence it would not have taken hold.

If I can be of any help to you, please let me know. And you are welcome here anytime.

Gary Evans
Midwest Motorglider Supplies
Ultralight Power Systems
2638 Roberts
Waukegan, ILL 60085
+
This letter and the enclosed catalog were received in less than a week after I mailed in my request - indicating that Gary is (at least currently) on top of his mail. You can judge the content and tone of the letter yourself. And, in spite of Gary's flattering remarks, please rest assured that the following evaluation is completely unbiased - well, as unbiased as possible after reading the letter.

CATALOG DESCRIPTION

The catalog consisted of six pages of product descriptions and a one-page order form. Most of the products were illustrated with a photograph. I was somewhat disappointed to see that there were only seven products available: (1) hollow braided polypropylene tow rope, (2) a hydraulic pressure gauge, (3) a 3-ring release, (4) a Mark V.C.B. Headset, (5) a high speed electric reel, (6) a king post mounted "CB" antenna, and (7) a threaded bridle towing release. Each product was clearly priced and if a delay beyond 2 - 4 weeks was expected in shipment, it was so specified. The prices were FOB Waukegan, IL and firm until 12-31-84.

I was pleased to see the following warning on the first page of the catalog: "These towing components are only intended for use by advanced pilots (USHGA level 4) who have received prior skyting instructions. Hang gliding, towing and skyting can be very dangerous without proper instruction and equipment."

As skyting becomes more popular and more acceptable such warnings are needed to dissuade the unqualified enthusiast from purchasing a set of skyting equipment and going out to kill himself.

HOLLOW BRAIDED POLYPROPYLENE TOW ROPE

The first item in the catalog is towline in 1000 ft spools. The catalog states, "A typcal skyting tow line consists of 1000' of 1/4" and 2000' of 3/16". The 3/16" section is to provide the necessary stretch to dampen tow pressure variations." The 3/16" rope costs $35.00/1000' and the 1/4" rope costs $40.00/1000' which is less than the $50.00/1000' I sell the parachute shroud line for.

PRESSURE GAUGE

Again, the catalog begins its product description with a short educational remark, "A hydraulic pressure gauge is the only way to monitor towline pressure. Accurate control of the line pressure is critical for a safe tow operation. (Do not attempt towing without a means of monitoring line tension.

Such reminders are appropriate at this time to encourage skyting safety. However, hydraulic gauges are not the ONLY safe way to monitor towline pressure. For example, Denis Cummings sells and electronic tension gauge (Skyting #20) and Butch Pritchett sells a pneumatic gauge (Skyting #22).

The Midwest Motorglider Supplies pressure gauge is different from any reported so far in Skyting. It has no hydraulic line, but attaches the (4-inch diameter) dial directly to the hydraulic cylinder. The idea is to mount the unit on the left front fender so that the gauge can be seen by the driver. The catalog says that this can be accomplished "without damage to the car body" but does not tell how it is done. (Installation instructions are supplied with the gauge.) The idea is intriguing, and I would like for someone to write up a report of how well the design works.

The fender mount gauge is only $99.50, considerably less than the typical $150 advertised for a pressure gauge. There is also a remote option available for $35.00 extra, which includes a magnetic gauge mount for the car hood. (Another interesting variation.)

THREE-RING RELEASE

The educational description of this product reads, "The 3-ring towing release is considered to be the state of the art for skyting. The release is the most critical piece of hardware in the towing system and is no place to experiment with untried ideas." I can't really argue with this statement.

The release, itself, seems to be quite standard with the 3-ring release on one end of a short strip of webbing and an attachment ring on the other end. The pull pin seems to be attached to the end or a wire with a loop in its other end for connecting the release line. The releases are $50.00 each, which seems a little high, and extra rope rings are available for $1.50 each, which seems to be a good price.

MARK V.C.B. HEADSET

The educational material on this item reads, "Due to the distance between tow vehicle and glider reliable communications are mandatory. A good headset puts the pilot in control of the tow operation. Hand held microphones are difficult to use and are unreliable due to wind noise. When quick radio communications are required it is no time to fly with one and reach for a microphone with the other." This sounds reasonable to me although I have never had an opportunity to try a radio headset.

The Mark V features include (1) one hole helmet mounting bracket with quick disconnect, (2) flipout adjustable ear cup for ease of helmet removal, (3) push-to-talk switch for control bar, (4) coil cord between headset and push-to-talk switch to provide for pilot movement during ground handling and launch, (5) one ear only design to allow the pilot to hear normally (which is especially important in hang gliding), (6) plugs directly into Radio Shack 5 watt C.B. radio with no modifications required, and (7) 30-day warranty and factory service available. The Mark V headsets are $125.00 each, which seems about normal for such items.

HIGH SPEED ELECTRIC REEL

Custom made reels are available on special order which reduce the turn-a-round time to minutes. This is the first item in the catalog without an educational comment included in the description. Let me remind you that in skyting it is common to distinguish between "winches" and "reels". "Power winches" are able to supply the power to launch and tow a hang glider; "payout winches" let rope out at reasonably constant tension for the flying glider while being pulled behind a vehicle; and "reels" are used to retrieve the towline after each flight and/or store it between flying sessions. A "high speed reel" is able to rapidly pull the line in after the pilot releases from tow.

Features of Midwest Motorglider Supplies reel include (1) 1000 ft/min retreive speed, (2) push button control, (3) universal bumper mount, (4) quality construction with replacement parts available, (5) heavy duty 12 volt electric motor with v-belt drive, (6) 3000 ft of rope capacity.

It was not clear to me how the reel mounted on the bumper of various cars, but since each reel is customized, I assume proper mounting and/or bracing techniques are available. The price of the reel is $425.00, which seems quite reasonable to me. (Allow 4-6 weeks for delivery).

KING POST MOUNTED "CB" ANTENNA

Another item without educational comment is the king post mounted antenna. According to the catalog, "The antenna is base loaded for full quarter wave 'CB' operation and is wired with cable and plug-in jack for 'Radio Shack' 5 watt six of forty channel hand-held radio. The antenna comes complete with a king post mounting bracket. Communications range with this antenna is 20 to 40 miles." Price is $40.00, which again seems quite reasonable.

THREADED-BRIDLE TOWING RELEASE

With the latest interest in the threaded bridle concept, this new entry to the catalog seems to be quite timely. The catalog description reads, "This release is for use with a threaded-bridle system in which the bridle (5mm perlon) strips through the rings after release and stays attached to the tow rope. Nothing is left on the glider except the keel mounted release. The release is constructed from aluminum and is hinged for easy keel attachment without glider disassembly. During use a release line is attached to the pilot's wrist."

Nothing was mentioned s to a source of perlon which seems to be a regional item (easy to get here in Colorado, impossible to get in South Texas). And I am a little concerned about the rope for which the release is designed. In Skyting #24, Ted Fillmore ((Gilmore)) points out that 11 mm perlon should be used instead of 9 mm because it is less likely to foul and less likely to injure the pilot when he releases or when the weak link breaks. I would think that 5 mm perlon would be increasing the risk of fouling and injury to unnecessary and unacceptable levels. Although 5 mm perlon may prove to be adequate for threaded bridles, I believe commercial vendors should stay with the larger rope until time proves this to be so. I do not know if Gary's release will accept 11 mm perlon without modification, so I suggest that you find out before buying one - unless, of course, you want to be one of the 5 mm perlon pioneers.

CONCLUSION

Overall I was very pleased with skyting's first catalog. Many of the necessary and hard to find skyting components were listed, the quality of the products seemed to be quite good, and the prices were very reasonable. By combining the parts available through this catalog with those items normally available locally, you could construct yourself a state-of-the-art, high quality skyting system. And if Gary continues to upgrade his inventory, it won't be long before you will have a single source where you can buy ALL of your skyting equipment.

SKYTING MILESTONES - WHERE ARE THEY?

I hope youze guys are having so much fun skyting that you simply don't have any time for letting us know what is happening. Because if that's not why you're not writing, then it means that you're having so much trouble that you don't have time to write - or else you're so busy doing other things that you haven't been able to skyte at all.

But, you know, even if you are all that busy skyting cross country and such, you can at least send us a line to let us know you didn't crack up in the outbacks and are still having trouble finding your way back home.

I expected great things in skyting this summer - both personal and national milestones - but so far I have received few reports. So if something interesting has happened in your skyting life, let us know.
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1984/07-09

WHEN ARE THEY GOING TO SEE THE SENSE
I'M FINISHED!!!
MAYBE A TRACTOR OR A LANDROVER WOULD DO THE JOB.
EITHER THESE CROSS WIND TAKE OFFS, HAVE STOP, OR WE NEED A NEW AIRFIELD.
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1984/08
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SKYTING NO.28
AUG 1984
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1984/08-01

COLORADO TOW TRAINING TECHNIQUES

by Donnell Hewett

This summer I was fortunate enough to spend a whole Saturday observing how Bob Faris of Ft. Collins, Colorado, trains his students to skyte. I am convinced that his methods are quite sound, and suitable for others to use. Of course, I do not intend to imply that his is the only safe method of training skyters, but since his is the first one described in any detail, it can be used as a standard of reference for comparing other systems and as a starting point for further developments. This article describes his system as I preceive it.

PREREQUISITES

Bob's tow training program is not designed for just anybody. If someone is just beginning to hang glide, Bob takes him out to a training hill and teaches him how to hang glide according to the conventional, time proven methods approved by USHGA. Only after the pilot has earned an intermediate (3) or advanced (4) rating is he considered qualified to take the tow training program.

As a result, all of the students coming to Bob's tow clinics and training sessions are experienced pilots, capable of handling their own gliders in all kinds of free flight conditions. The only skills they lack are those associated with towing.

By insisting that everyone have these prerequisites before taking his tow training course, Bob is able to reduce the amount of material that has to be covered in the course and to decrease the probability of a serious accident occurring. In fact, most of Bob's students learn to skyte safely in a single session (weather permitting). And as far as accidents are concerned, Bob has instructed thousands of tows without a single major accident. (Yes, they have broken some down tubes and experienced a few minor scrapes and bruses.)

GROUND SCHOOL

Bob's ground school is short and sweet. Since he doesn't have to cover the basics of hang gliding, he sticks to the essentials of towing and emphasizes the differences between towing and free flight. The idea is to make sure the pilots understand the basics of skyting theory and know what to expect and how they react under certain conditions.

Actually, I got there late - after things were into full swing - so I don't know whether or not Bob holds a formal ground school session before flying. I suspect that he does not - primarily because he was consistantly repeating important information as it became pertinent and obviously avoided the temptation to "overload" the pilot's mental circuitry by giving him too much to learn at one time. Bob was very good at observing the pilot's individual weak points and feeding him just the information he needed to strengthen those points.

As far as the skyting takeoff was concerned, Bob had a simple formula that he repeated time and again: "Keep your wings level, keep the nose high, and shuffle your feet." Let's analyze each of these instructions in more detail:

(1) Keep your wings level.

Now you would think that any experienced hang glider pilot would know to keep his wings level on takeoff. But remember, conventional pilots are not familiar with CROSS WIND TAKEOFFS! As for as cross wind takeoffs are concerned, all of their training and experience has been, "Don't do it!" But since cross wind takeoffs are a normal, expected part of skyting these pilots needed to learn how to do it. Furthermore, the day I was there, the winds were really ideal for learning cross wind takeoffs: light and variable with a typical value of 6 mph at 45 degrees but with an occasional 3 mph at 90 degrees.

Of course, such conditions did not appear "ideal" to these student pilots, who would not dream of launching off a hill in such conditions. The pilots were obviously uneasy about the cross wind, would frequently lose their concentration and drop one wing or the other. More than once a pilot who had the necessary skills to launch under the given conditions would psych himself out of launching, waiting for "just the right conditions". When this would happen, Bob would assure him that he was able to launch safely, but if he felt he didn't have the necessary skill, then he should get off the towline and let someone else launch who did. The student would then go ahead and make a perfect takeoff.

The first time I saw this "high pressure tactic" used on a student, I could hardly believe my ears. But on further reflection I noticed that this tactic was used only on pilots who had already proven themselves (by previously making several successful tow launches) and were simply letting their fear of cross winds keep them from progressing. Bob emphasized that as long as they kept their wings level, the cross wind takeoff was not problem. Since these pilots did have the skills necessary to keep their wings level, then, sure enough, the cross wind takeoff was no problem.

(2) Keep the nose high.

Now it is easy to understand why conventional pilots have trouble with this one. It is exactly the opposite to what they have learned from day one. All of their previous training and conditioned reflexes have told them to keep the nose down in order to avoid a stall - especially during takeoff. Naturally these pilots found it difficult to begin their takeoff runs with the nose-high attitude necessary for safe towing. More than once they had to be reminded to keep their nose up.

(3) Shuffle your feet.

Once again, the instruction was exactly the opposite to what they had previously been taught. A normal gravity powered takeoff requires that the pilot run HARD - generally as hard as he can run. Bob's method of preventing his students from outrunning the accelerating vehicle, leaning forward (another ingrained habit), losing their balance, and falling, was to insist that they lean back and "shuffle" their feet. This means that they should shift their weight lightly from foot to foot (while leaning back and maintaining their balance), letting the towline pull them forward, forcing their feet to slide on the dirt.

EQUIPMENT

All of Bob's students begin their tow training on a glider without a shifting crossbar. This is to eliminate the adverse yaw problem associated with shifting cross bar, double surface gliders.

The bridle is a double release skyting bridle with an auto-release line on the bottom. The top release is activated by a pull string running to the flight wire about 6 or 8 inches in front of the control bar. It is activated by pulling or pushing anywhere on the string. To make the string easier to find in an emergency situation, a hollow plastic ball is tied to it at approximately the position a prone pilot would normally grab the string (about 8 inches above its lower end). See Fig. 1.

Both releases are standard three-ring releases and stay with the pilot and glider upon release. The top release is on an extension line which places the release below the flying wires and eliminates any possibility of bridle entanglement with the glider. After release, the wind blows the release and extension line behind the pilot and out of the way. The bottom release is built into a V-shaped belt whose ends clip onto each side of the pilot's harness near his point of suspension. The belt is not quite long enough to trip the pilot on landing.

There is a leader (about 25 ft?) between the bridle and the weak link. The weak link breaks at about 180 lb and consists of a short nylon cord with a Boline knot in each end. After each flight the weak link is replaced by a fresh, new one. In order to have a plentiful supply of weak links ready to go, Bob cuts and ties them before the training session. To replace the weak link, one need only slip one end onto a locking ring attached to the leader, thread the other end through a loop in the towline and slip it back on the locking ring. See Fig. 2.

The towline consists of 2000 ft of non-elastic steel cable (at the bottom) and 500 ft of elastic nylon line (approximately 1/8 inch diameter). There is no drag chute on the towline.

After each flight the towline is rewound by a powered takeup reel on the rear bumper of the tow vehicle.

During the flight, the towline is attached to a calibrated spring gauge mounted to the windshield of the vehicle. See Fig. 3.

The gauge appears to be quite accurate, reliable, and easy to read.

CREW AND COMMUNICATIONS

Bob uses a trained driver and does his instructing from the launch site. CB radios are used for communication - one the car, one in Bob's hand, and one mounted to the crossbar of the glider in such a position that the student can hear instructions while in flight.

SIGNALS

Bob uses the following signals over the CB radios during the critical takeoff situation:

"Ready to take up slack." This is the signal given by the driver when he has finished laying out the towline, has it attached to the spring gauge, and is ready to go.

"Take up slack." This is the signal given by the launch director (Bob) after the pilot is standing up and ready for the slack to be taken out of the towline. On this signal the driver slowly takes up slack and loads about 40 pounds of tension on the line. The pilot holds back while the tension is building.

"Stand by." This is the signal given by the launch director to indicate that the pilot is almost ready for takeoff. The driver starts his engine and gets ready to accelerate hard on the next signal.

"Hit it!" This signal is given by the launch director to indicate that the pilot is ready for immediate power. The driver instantly accelerates as fast as possible to 100 pounds of tension and holds it until the pilot has taken off and is climbing smoothly. (If there is a significant wind gradient, it would probably be wise to maintain this tension through the gradient.) Then he may increase the tension to 120 pounds or more, depending upon the pilot's experience.

NOTE: The driver should not accelerate on any other command, such as "Take off!" (They may have actually said, "Slack off!") or "Go, go!" (They may have said, "Oh, no!"). Everyone should either use the agreed upon signals when towing, or else don't tow at all. To do otherwise might catch the pilot off guard and cause an accident. (I know, because two weeks later I was spotting when the driver and I thought we heard "Take off!" The launch director had actually said, "Slack off!" - because the pilot was having a few problems. Of course, those problems were nothing compared to the ones he encountered once we began accelerating. After this experience there were no more launches without the proper signals performed in the right order.)

As mentioned before, during the towing takeoff, the pilot should concentrate on keeping his wings level, his nose high, and shuffling his feet (short sliding steps) instead of running, so the tension will build up to takeoff levels. If he runs, he is likely to lean forward, drop the nose, and nose in. (Use wheels!) If he is using a cocoon harness, stuff the boot back between his legs. (This is another reason to shuffle instead of running.)

"All stop!" This signal was not used by Bob, but I saw a need for it. Specifically, if the "Stand by!" signal has been given, and the conditions change so that the pilot in no longer ready to take off, the launch director should give this signal to let the driver know that he can kill the engine and relax a minute. When the pilot is again ready to take off, the "Stand by!" signal will be given again. Without the "All stop!" signal, the driver can sit for what seems like hours with the engine reved up, one foot on the break, one foot on the clutch, hand on the gear shift, one eye on the tension gauge, one on the rear view mirror, and one on the road ahead.

"Abort!" This signal was not used by Bob, either, but I believe it would be useful. If the pilot falls on takeoff, the bridle comes undone, the pilot needs to rest, or anything else causes the takeoff to be aborted, this command should be given. It tells the driver to stop immediately and/or let the tension go slack. When the pilot is ready to continue, the "Take up slack." signal should be given again.

FLIGHT PLAN

Bob's flight plan for his students is understood from the beginning. The pilot is to climb to about 1000 ft or more (depending upon conditions and how many towing flights he has had). He is to concentrate on keeping the glider flying straight behind the vehicle. No maneuvers whatsoever are to be performed except the "punch it" technique of getting the glider back on course. (This technique has been mentioned in SKYTING before: When a wind gust or thermal tries to roll, yaw, or otherwise turn the glider off course, the pilot makes a hard weight shift correction and then immediately gets back on center. He does NOT shift his weight and hold it until the glider responds.) This practice is in preparation for flying the shifting crossbar gliders, where the shift-and-hold maneuver will result in excessive adverse yaw tendencies whereas the punch-it technique can actually stop the yaw oscillations even if they do get started.

By towing to 1000 ft plus, the pilot not only gains more towing flight time, but he also has the altitude to make corrections (or even release) if anything goes wrong. Furthermore, unless something does go wrong, the pilot should be able to make it back to takeoff even on his first tow flight. This eliminates any need for hauling the glider back to takeoff, thereby speeding things up considerably.

GRADUAL ADVANCEMENT

Once the pilot has had sufficient experience (say 5 flights) and demonstrated his ability to handle the rigid crossbar glider in typical thermaling conditions, he is allowed to fly his own shifting crossbar, double surfaced glider in smooth conditions (i.e. no thermal activities or wind gusts). I recommend that the tension be kept low on his maiden flight (say 100 pounds or less). He will not climb as fast, but the difference between towed flight and free flight is less under light tension, and the pilot needs to recognize the differences before they become too large to handle. Besides, with the higher performance glider, he should still be able to make it back to takeoff.

As he gains experience and confidence, he may gradually tow in more adverse conditions until he is able to handle cross winds and thermaling conditions.

ADVANCE TECHNIQUE

Bob demonstrated what could be called an advanced towing technique - one that I had never seen before. When the cross wind became so severe (say 10 mph at 90 degrees) that it was potentially dangerous to launch normally (the pilot could not hold his wings level), then Bob held his upwind wing steady and ran with the pilot until the glider was flying under control. This "wing running" takeoff technique has been used for a long time with conventional gliders (sail planes) and works just as effectively for hang gliders. I witnessed picture perfect launches in conditions I previously would have classified as being too dangerous to try. Just as windy cliff launches need assistance in order to be safe, so do severe cross wind towing launches need assistance to be safe.

COMMENTS

I would like to take this opportunity to thank Bob for allowing me to witness and analyze his towing instruction session. I hope you, the SKYTING reader, have learned something useful from this report. I certainly learned a lot form watching the session in person. In fact at the end of the session, I even got to skyte 4 times higher than I had ever skyted before. But that's another story which I'll tell you about some other time.
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Fig. 1. Skyting Bridle and Releases

DH
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Fig. 2. Weak Link Setup.
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Fig. 3. Tension Gauge Setup.
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1984/08-02

APOLOGY

I would like to apologize for being so late in getting out this issue of SKYTING.

You know that I spent the summer in Colorado. Well, I was not able to get this issue out before leaving Colorado, and once I got back to Kingsville, I had certain pressing commitments which simply had to be fulfilled before working on the Newsletter. I'm sorry, and I'll try to better next time.

Donnell
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1984/08-03

PETITION FOR EXEMPTION FOR UTRALIGHT TOWING

The following material (written by Dennis Pagen) was sent to the FAA by the USHGA in an effort to legalize aerotowing in the United States. According to Hardy Snyman, who was kind enough to send me this information, the FAA has reviewed and accepted the material, but it remains now in the 120-day waiting period, to see if it stands the test of public approval. USHGA officials are optimistic it will pass.

FAA
Rules Docket
AGC-204
800 Independence Ave. S.W.
Washington, D.C. 20591

RE:
Petition for exemption from FAR 91.17
United States Hang Gliding Association

Gentlemen:

The United States Hang Gliding Association (USHGA) hereby petitions, pursuant to section 11.25 of the Federal Aviation Regulations, for an exemption from FAR 91.17 so that an unpowered ultralight (hang glider) may be towed aloft by a powered ultralight under the guidelines of FAR 103 and the USHGA rules continued herein. This petition is intended to apply to recreational and instructional use only.

INTEREST OF PETITIONER

The United States Hang Gliding Association is a nonprofit organization dedicated to pilot safety through education and training, accident prevention and research. Of particular significance is the USHGA's expertise in the area of flight and ground instruction. For over ten years the USHGA's programs of pilot certification in instruction certification have been recognized internationally as a model of excellence. Many foreign organizations have used the USHGA programs verbatim while most other countries honor the USHGA pilot rating system in the case of visiting US pilots. Thousands of students are taught every year under the auspices of the USHGA programs with a very admirable safety record.

The USHGA also has a long standing interest in the safe conduct of powered ultralight flying and instruction. Since powered ultralights evolved from hang gliders in the US, the USHGA realized that the organization was in the best position to establish safety guidelines. To that end, programs for instructor certification and pilot testing were created in 1979. These programs along with insurance coverage for powered ultralight pilots were in effect until other organizations (notably EAA and AOPA) developed their own safety programs. To date no other programs have equaled those of the USHGA in terms of thoroughness and depth in regards to powered ultralight instruction.

The USHGA's interest in towing of unpowered ultralights with powered ultralights is to enhance the safety and enjoyment of instruction, competition, and recreational flying. The organization's extensive background in these activities provides the basis for this interest. The USHGA contends that it is in a better position than any other organization to set standards and monitor the practice of said towing activity. As such, the exemption should apply to all pilots operating under FAR 103 (powered and unpowered) who meet the USHGA requirements for towing. This policy is in agreement with the general self-regulating policies for ultralights.

COMMENTS IN SUPPORT OF PETITION

Under the current regulation (FAR 91.17), a powered ultralight towing an unpowered ultralight must be a registered experimental with the pilot in command possessing a pilots license. This in untenable for two reasons. First, to be registered experimental the ultralight must be amateur built. This is impossible for most ultralights suitable for towing. A tow vehicle should have a slow stall and cruise speed which indicates the Dacron covered fixed wings or hang gliders with trike systems attached. For a hang glider/trike in particular, the 51% construction rule is impossible.

Secondly, requiring the tow pilot to obtain a pilots certificate is unnecessary for the piloting skills acquired in conventional aircraft do not directly apply to the slower ultralights and are detrimental to the pilot of a trike system (the controls movements are backwards). The time and money spent in obtaining a pilots certificate would be better directed to learning the rules of operation of ultralights in terms of other air traffic, small scale weather effects and specific controls of the ultralight in question.

The USHGA standards for towing include requirements that both towing and towed pilots must meet in regards to pilot knowledge and skill. Also, these standards set limitations on the tow vehicle, towed glider and tow line system, similar to the FAA's guidelines for towing sailplanes.

Grant of the exemption would not jeopardize the FAA'S desire to protect unwary passengers, for both pilots would be in command of their craft operating under FAR 103. In the case of a student being towed, that student would meet the applicable USHGA standards and must be informed by the tow pilot of the experimental nature of the operation.

Grant of the exemption would not be contrary of the sport and recreation aspect of ultralight activities. We not that hang gliding instruction utilizes recreational equipment and therefore such instruction is not a "for-hire" operation. Instruction conducted under the terms of this exemption would epitomize the FAA's philosophy of self-regulation of the hang gliding community under FAA guidelines.

Grant of the exemption would be in the public interest because it will enhance the safety and education of hang gliding instruction as well as general recreation. The segment of the public actively engaged in hang gliding or hang gliding instruction will this benefit while history shows that the practice of towing unpowered ultralights by powered ultralights does not endanger the general public.

The safety record of ultralight towing is impressive. In the US, various experimenters have practiced air-to-air towing for over two years with no reported problems inherent in the system. In France, a successful system has be under development for over three years. The tow system has been available to the public for one and one half years with a history of over 3,000 individual pilots being towed, representing scores of thousands of towing flights. There has not been one accident with this towing system according to French officials. A similar system under USHGA standards should prove equally as safe.

The real safety enhancement comes with hang gliding instruction. Once a student achieves a certain skill level he can be towed aloft in increasingly higher altitudes and practice flight patterns and landing approaches in a gradual manner. This will overcome the current problem with hang gliding instruction in many areas where students often have to graduate from a training hill of 100 feet or less to the next available size mountain of 1000 feet or more. This is a serious drawback of hang gliding instruction that can be corrected with single place or two place towing.

For a similar reason, hang gliding training will be more thorough. Currently, weather plays a major role in the conduction of hang gliding lessons. The winds must blow right for the training hill which does not occur often enough in many areas. A student oftes loses patience or the training is not as complete as it could be if succeeding days offered ideal conditions. This problem will be solved with towing training, for a great many flights can be achieved in a short time during morning or evening calm periods since there will be no need to wait for the winds or carry or drive the hang glider back up the hill.

Another enhancement of safety that the exemption will foster is the everyday recreational operation of hang gliders by experienced pilots. The most dangerous period of operation of a hang glider is during windy (soarable) conditions while launching. The presence of trees in the East and powerful thermals rising up the mountain face in the West increase these dangers. Towing up in the middle of a valley and flying over to the mountain when ridge soaring or using thermals over flat ground will avoid this danger (thermals tend to be less vigorous when they lift from a valley floor). The problem of launching in a crosswind will also be eliminated with a towing system since hang gliding launch sites are limited in the directions they face while a tow operation can turn into the wind for taking off. Competition will likewise be safer, for pilots will not be induced to launch in adverse conditions and will be more spread out as in sailplane competitions.

In addition to the above reasons, the exemption will enhance safety because:

1. Instructors using a towing system will be qualified by the USHGA. This will be a more pertinent qualification than that provided by the FAA under FAR 61. Furthermore, the USHGA will monitor instructors through the existing programs of certification and record keeping.

2. The USHGA has established a system of accident data collection and dissemination of safety information. This data is published in a number of publications and is available to the FAA. This data is used as a basis for modifying instructor courses to improve the safety of the sport.

3. The USHGA will constantly monitor the practice of air-to-air towing so as to correct any potential problem and inform pilots of latest equipment and technique developments.

CONDITIONS OF EXEMPTION

In order for an ultralight air-to-air towing operation to qualify for an exemption to FAR 91.17, the following conditions must be met:

The following requirements must be understood and adhered to:

1. Both vehicles (powered and unpowered ultralight) must meet the vehicle standards of Part 103.

2. Both vehicles must meet the requirements of the USHGA Towing standards.

3. While towing, both vehicles may be used for recreational purposes only.

4. The pilot of the powered ultralight vehicle must possess and have in his possession a current tow rating issued by the USHGA.

5. The pilot of the unpowered ultralight must possess and have in his possession a current pilot rating issued by the USHGA. This rating shall be at least a USHGA Intermediate (level 3) for a recreational pilot and a USHGA Novice (level 2) for a student under the supervision of a USHGA certified instructor.

6. The unpowered ultralight (hang glider) may be used for two-place instructional purposes if the instructor possesses a current USHGA instructor rating and is operating under the conditions of the two-place exemption.

7. Prior to a student's first flight in a towed ultralight (hang glider), the pilot of the powered ultralight and the instructor must inform the student that instruction under tow is conducted under an exemption granted to the USHGA by the FAA.

8. The instructor must keep a written record of all operations conducted under this exemption. The record shall include the students name, the date and the location of the instruction. The record must be maintained for twelve calendar months. The instructors shall present this record for inspection upon reasonable request by the USHGA or the FAA.

9. The instructor shall notify the USHGA within thirty days of any accident occurring while operating under this exemption. This information shall be made available upon reasonable request by the FAA.

10. The structural integrity of the tow hitch and tow line must be substantiated in accordance to USHGA standards and recorded in the tow vehicle records by the owner.

11. The operational capabilities of the powered ultralight to tow and release a hang glider satisfactorily must be demonstrated in an assigned test area under actual operational conditions to a USHGA inspector, and be duly recorded in the tow vehicle records.

12. Both towed and towing pilots must obey operational procedures set forth in the USHGA Towing standards.

SUMMARY FOR FEDERAL REGISTER

The United States Hang Gliding and Association (USHGA) petitions for an exemptioon from FAR 91.17 so that an unpowered ultralight (hang glider) may be towed aloft by a powered ultralight under these guidelines of FAR 103 and the USHGA Towing Standards. This petition is intended to apply to recreational and instructional use only.

Respectfully Submitted,
Steve Hawxhurst
USHGA President
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SKYTING PROGRESS IN ISRAEL
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1984/08-04

Dear Donnell,

In the end of June I had in Nahal-Oz a visit of two pilots from our association. One of them is responsible for safety precautions for hang gliding in Israel. The other is one of the first hang gliding pilots in Israel and a professional pilot of aircrafts. After we talked and discussed the system, I showed them my equipment and ... launched. Later each of them made four flights. Their conclusions will not surprise you.

For me it was a great day. After about one year that I argued with our association about Skyting, they decided: it is safe and can be used by other pilots (hang 4 meanwhile). The association now has a committee (I'm a member in it.) to examine all aspects of skyting. I hope soon we will finish our job.

About the system and new changes I made and am using here:

(1) The driver has in front of the car an air speed meter. It is useful especially for days with slow winds.

(2) The driver informs the pilot (with the radio) each 15 seconds or so about the tension.

(3) Before the pilot orders "Go" to the driver, he brings the radio to the pushed position (ready to speak. The pilot releases it when he is in the air. I use for it a 15 mm PVC cylinder and a rubber belt.

There is a new device I started to work on. I'd like to tell you about it. Maybe in the mean time someone else will "buy" the idea. I want to let the pilot know the accurate tension in the line. The device I want to use for it is a strain gauge with liquid crystal display. If it will work good, I'll replace the hydraulic cylinder that is in the car.

One of my problems now is to teach other pilots about skyting. I'll be thankful if you can give me some advice based upon your experience.

Heber Itzhak
Nachal Oz, ISRAEL
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1984/08-05

Dear Heber,

It is good news to hear that others in your association have finally begun to listen to your views on skyting. I know how it feels to finally be heard.

Let me make a few comments here on your letter. First about your "changes". (1) An air speed indicator on the vehicle is a good idea, but the tension gauge is far more important. In thermaling conditions (even in light and variable winds) the vehicle air speed at ground level and the glider air speed at altitude can be far different from one another.

(2) Your idea of informing the glider pilot of his towline tension every 15 seconds or so sounds like a good idea. However, if the driver is doing his job right, the tension should never vary very far from the preselected value, so just how valuable is this information. And if the vehicle is transmitting every 15 seconds or so and the pilot needs to send an emergency message, that message may not get through.

(3) Locking the pilot's transmitter "on" during takeoff sounds like a good idea. The problem I see is that in an emergency situation he may be misunderstood. Suppose he shouts, "Oh, No!" But over the radio it sounds like, "Go, go!" What should the driver do? Speed up, slow down, or stop? Voice communication over the radio needs clearly understood, practiced, and followed signals. In my opinion, an experienced "launch director" can give better instructions to the driver during take off than the pilot himself. But if the pilot's transmitter is locked on, the launch director's instructions may not be heard by the driver. So as with everything else, locking down the pilot's transmitter has its advantages and disadvantages.

The electronic tension gauge you mentioned sound much like the one described in Skyting No. 20 made by Denis Cummings from about $150. You may want to contact Denis before proceeding with your own design.

Now concerning teaching others to skyte. I believe the article, COLORADO TOW TRAINING TECHNIQUES located elsewhere in this issue, will answer many of your questions. Let me know if you have any other questions.

Donnell
*
*

1984/09
*
SKYTING NO.29
SEP. 1984
*
1984/09-01

1984 TOWING FATALITIES

Doug Hildreth, Chairman, Accident Review, USHGA, has recently published his mid-year accident review. (Hang Gliding, Sept., 1984) Generally it is the same old song of pilots and crew repeating the same old mistakes. However, there is one very disturbing trend which heretofore has never occurred (unless it was in the very early stages of hang glider development). Namely, 50% of the reported hang glider fatalities this year are associated with TOWING!

Out of four reported hang gliding fatalities, two were from towing: John Shook, of Arizona, failed to hook in; and Mike Harrison, of Virginia, was killed for unknown reasons. (The two non-towing fatalities were the result of landing in the surf and drowning, and flying into a rotor.)

Personally, I find this very disturbing. For I am confident that towing does NOT constitute 50% of the hang glider flying. This means that, statically, TOWING IS STILL SIGNIFICANTLY MORE DANGEROUS THAN FREE FLYING.

The only bright spot in this new picture is that, so far, no subscriber to the SKYTING Newsletter has been killed while towing. I hope this is because you are better informed about the dangers and problems associated with towing than those associated with towing than than those who do not subscribe. Of course it may also be the fact that you, who are willing to part with your hard earned $10.00 per year ($20.00 if you are a foreign subscriber) just to keep up with the latest towing developments, are more safety conscious than others. Or (and I hope this is not the case) it may be that the statistics have just not caught up with you SKYTING subscribers yet.

But regardless of the reasons, please remember to skyte safely - and if you see anyone violating the skyting criteria, please educate them if at all possible.

Donnell
*
1984/09-02

THREADED BRIDLE PROBLEMS

by Gary Evans

Several negative characteristics of the threaded bridle have been learned through actual use. While they may not be reason to discontinue use of the system, the potential problems should be understood by the user.

On two occasions the rope has snapped the pilot hard enough to draw blood. A full harness will minimize this problem but one strike was on the arm through a jacket sleeve. The potential therefore exists to be hit in the face or eye.

The second problem is having the rope tangle while stripping through the rings. Occasionally the rope can be felt to spin around the base tube and then instantly unwind. It happens almost too fast to be seen, but it can be felt.

During two releases the rope (7 mm perlon) tangled on the body ring about four inches from the end. One pulled itself free after several seconds but the other required about a minute to untie using both hands.

From these experiences we can draw several conclusions:

1. A standard skyting bridle with a singe three-ring release at the apex with a release line to the pilot's wrist is probably still the most foolproof system to date.

3. Always turn your head during release to avoid being hit in the face.

4. The possibility also exists for the unthreading rope to tangle elsewhere (e.g. sidewire, harness, or base tube) with unknown results.
*
1984/09-03

USHGA TOWING STANDARDS

(Editor Note: Last month, in SKYTING No. 28, we published USHGA's Petition For Exemption for Ultralight Towing. There was not room in that issue to include the USHGA Towing Standards, which were actually part of that petition. Therefore these Towing Standards are being published this month in order to complete that package of information.)

I. PILOT QUALIFICATIONS

A. POWERED ULTRALLIGHT PILOT

1. A total of 50 logged hours in powered ultralights and 10 logged flights in the towing vehicle or possession of an USHGA Advanced rating and 25 logged flights in the towing vehicle.

2. Successful completion of the Intermediate and Advanced USHGA pilot rating tests or possession of a USHGA Advanced rating to assure that the towing pilot understands the principles of hang glider flight as well as aerodynamics, small scale weather and flight rules in general.

3. Demonstrate five (5) successful tows to a USHGA Inspector with an experienced pilot in the towed vehicle (hang glider).

4. Review the USHGA Towing Guidelines.

B. UNPOWERED ULTRALIGHT PILOT

1. A special air-to-air tow rating will be issued to a pilot possessing a USHGA Intermediate rating (level 3) upon completion of five (5) successful tows under the supervision of a USHGA Certified Instructor qualified to teach towing.

2. A student possessing at least a USHGA Novice rating (level 2) may tow at any time under the guidelines of a qualified instructor.

C. INSTRUCTOR AND INSPECTION QUALIFICATIONS

1. An instructor of air-to-air towing of ultralights must posses a USHGA Instructor Certification and complete ten (10) successful tows before a USHGA Inspector. It is desirable but not necessary that such an instructor also be qualified as a powered ultralight tow pilot.

2. A USHGA Inspector is a USHGA Instructor or USHGA Observer with a minimum of five (5) successful tows.

D. EQUIPMENT STANDARDS

1. The tow vehicle (powered ultralight) must have a rated thrust of at least 250 lbs.

2. The towed vehicle (unpowered ultralight) must meet or exceed the Hang Glider Manufacturers Association's Airworthiness Standards.

3. The tow line connection to the towing vehicle must be arranged so as to not hinder the control system of the towing vehicle.

4. A pilot operational release must connect the tow line to the towing vehicle. This release must be operational with zero tow line force up to twice the rated breaking strength of the tow line.

5. A weak link must be placed at both ends of the tow line. This weak link must have a breaking strength less than twice the weight of the hang glider and pilot combination.

6. A release must be placed at the hang glider end of the tow line within easy reach of the pilot. This release shall be operational with zero tow line force up to twice the rated breaking strength of the tow line.

7. A drogue parachute must be placed midway to 3/4 back from the tow vehicle on the tow line to prevent the tow line from reaching the tow vehicle propeller.

8. The tow line must be at least twice as strong as the weak link in use.

E. OPERATIONAL STANDARDS

1. The pilots of both the towed and towing vehicles must have an agreed upon general course of action including take off and release signals, airspeeds, and emergency procedures for each pilot.

2. No pilot of a powered or unpowered ultralight may intentionally release a towline in a mannor so as to endanger the life or property of another.

3. The pilot of the powered ultralight must yield right of way to the unpowered ultralight after release and remain well clear during landing so as to avoid wake turbulence problems.
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1984/09-04

AMERICA'S FIRST AERO TOW INCIDENT

by Dave Garrison
Operations Manager
Skylines, West

During an aero towing session at Salinas recently the following incident occurred, fortunately with only minor injury as the result. However, we feel the lessons learned from the incident are important and that all operators of Skylines towing systems should be made aware of the details and take note of the conclusions reached.

DESCRIPTION OF INCIDENT

At approximately 1200 feet the tug and glider pilots were practicing 360 degree turns on tow in smooth conditions.

On completion of a left hand 360 degree, a right turn was initiated by the tug pilot. The glider pilot (making his third tow) was slow to respond and began a lockout to the left.

The tug pilot began the normal correction of turning left, reducing line tension and attempting to get back in front of the glider.

This maneuver coincided with the glider pilot pulling in and attempting to roll to the right to correct the lockout. This had the effect of accelerating the glider rapidly, and the glider gained on the tug very quickly before going into a second lockout to the left. This combination allowed a situation, momentarily, where there was sufficient line slack and the relative positions were such that the tug was able to turn into the line and hook it on the left wing.

The line almost immediately went taught again as the glider went into the second lockout which developed very rapidly. The increasing line tension pulled the tug's left wing down, tearing the sail from the trailing edge to the leading edge at batten number five, and causing the tug to invert. Subsequent investigation showed that on inversion the trike fell into the wing, the left hand upper wire failed at the kingpost, and the wings folded negatively. The tug went into a rapid spin to the ground. As the tug pilot, I sustained a broken wrist and brusing. The glider pilot released at the point of the tug's inversion and made a normal landing.

CAUSES ANALYSIS

As is usually the case a combinatin of factors were involved. Had any of these been removed the accident would not have occurred.

1- Subsequent testing of the weak links being used at the time showed that under certain conditions (e.g., with a gradually increasing load combined with the towline's elasticity) they could reach up to one and a half times their correct breaking load.

2- Misjudgement was made by the tug pilot in trying to correct a lockout situation that was developing too rapidly and the glider should have been released.

3- Misjudgement was made by the glider pilot in not releasing before the lockout became too radical. From his statements afterwards it also became apparent that he was placing too much reliance on the weak link breaking rather than making his own decision to release.

4- In general, the very flexibility of the system al&owed a measure of overconfidence in the ability to correct almost any situation and remain on tow. This, combined with a reluctance to drop tows unnecessarily, thereby wasting time, undoubetedly led to unacceptable narrowing of safety margins.

REMEDIES

1- A new method of testing weak links has been devised to simulate the elasticity of the tow line and gradually applied load. DO NOT use a weak link stronger than 180 pounds.

2- In situations where the glider gets off line laterally, the glider pilot should release BEFORE and not WHEN he/she reaches the limit of his control authority. He/she should NOT assume that the weak link will do this job for him.

3- The tug pilot, if he observes the glider pilot reaching the above situation and not releasing, should do so without delay.

4- The technique of turning the tug, to reduce line tension and get back in front of the glider should be used with discretion, i.e., only where the glider is mildly off line, and NOT to recover a radical lock out.

5- A wide margin should be left between what is POSSIBLE with the system and what is PRACTICED. Considerations of convenience and/or productivity (getting more tows done while pilots are waiting anxiously, or not wishing to release because of the time delays involved) must not be allowed to influence in any way decisions affecting the safely margin.

In short, if in doubt, release!
*
1984/09-05

COMMENTS ON ABOVE

Although I cannot disagree with Dave Garrison's conclusions, I am afraid he failed to recognize the one factor that contributed the most to the above incident - namely the fact that they were performing maneuvers in a training situation. Maneuvering on tow (even in smooth conditions) is significantly more dangerous than straight line towing (even in thermaling conditions) especially when using a short towline as in aero towing. Since there is nothing to be gained by performing 360's (and especially reversed 360's) on tow, while there is much to lose (slower climb rate and increased danger), the flight plan for ALL training operations should incorporate absolutely no maneuvers except those essential for staying on course.

by Donnell Hewett
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1984/09-06

A VISIT TO BRIGHTON

Tony Webb
Norfolk, ENGLAND

It took Rona and me 1 1/2 hours to drive from Norfolk to Brighton, something we as towers are not used to. The weather improved from blowy conditions to gentle and warm during our drive, arriving in glourius sunshine.

Ian Grayland and company welcomed us and so we were loaded and heading for Devil's Dyke. The plan was to test out the 140 Clubman (a new glider manufactured by Aerial Arts in Brighton) and then onto the tow site for some real flying. The sight was covered with disowned gliders waiting for the sea breeze to cease.

Half an hour went by and we were heading towards the other side of Brighton to a chosen site we understood would be suitable for a tow demo and trial.

Rona and I were pleased with the view and the gentle slope to the cliffs. The site was grassed (freshly cut). We quickly set up and did the necessary winch and driver checks. Dave Woolford was elected to drive. We put him through the paces.

I was nervous about strangers watching, especially being at a new site which was a little different from a flat runway. There was also the unknown characteristics of the air and turbulence from the cliffs at lower levels and wind shear above. I took the Cutless and Lake step-up bridle up first as a wind dummy check. The first flight after a little man tow went well to 25 ft and then the retract rubber broke, which jerked the nose up and resulted in a shock weak link break. I did not release the line - only remembering to do so later as I realized the leader was being dragged over the wire fence. No harm was done except to upset my cool.

The second flight with the threader resulted in a cool takeoff to 30 ft. Then the stretcher snapped due to previous excessive wear on the concrete. I pulled in and landed with no problems. We replaced the stretcher with a new line and made a mental note to increase the strength of this portion of the line in the near future.

The third flight, due to excitement and a number of questions being asked plus more strangers being around, I committed an incredible book: I failed the "clip-in" routine and did not clip in the top. The glider lifted easily and hung around over my head but tracked beautifully straight. I realized my error, screamed stop, and tucked the bar in a little which brought the kite an inch or so lower. Then I released the line. I am pleased on reflection that it happened to me instead of someone else. Surprisingly enough I remained in control of the machine even in that situation. I will do some more studies on this subject.

The fourth flight was smooth. I had settled down and had some knowledge of what to expect. Good takeoff despite the 40 degree cross wind at 10-15 mph. I paid particular caution to the probability of turbulence, but was rewarded with a smooth sea breeze. The view was wonderful and distracted my attention to detail when dropping the line. The line dragged across the fence and caused Rona a little extra work in recoiling. My landing was comfortable, experiencing a little compression on the top of the hill which slowed my descent.

We tackled the Clubman, ready for flight, paying special attention to the tow leg point which I fitted 12 inches in front of the static balance point. I since believe this to be a little far forward, but it was comfortable in those conditions allowing a little push out control. We man towed a short distance, then make ready for a high flight. The takeoff I made fast with plenty of air speed. The kite remained obedient and level. I climbed to 60 ft and converted to prone. The machine is sweet, quickly setting into a flight path slightly into the wind and remained smooth hands off. I was able to push out and demand more line as I had plenty of air speed due to the tow position. The kite climbed quickly with a good height estimated at 800 - 1000. (I had an altimeter attached to my wrist but I didn't think to glance down at it.) The kite was so comfortable I had time to wonder why a person had run out to the tow vehicle. I later found out he was a member of the law who was rather upset at the car driving on the grass. When the car had stopped, I released the line (onto the field this time). The Clubman responded well to pulled-on speed, losing little height - seemingly just increasing air speed. The roll control was easy and fast but required little or no skill. 360's were a pleasure. The only thing that had to be remembered was the faster landing speed, so being brave I gave myself the best part of 2 acres to land on.

The machine was designed for P1 pilots. I felt that it is indeed that, but would add that a lot of advanced pilots will be flying it. You can walk a long way with 46.5 lb on your shoulder.

The day finished with Rona having a trial man tow or two along with Ian, Nick, John, Joe, Lesley, Richard and Dave. They all enjoyed the experience immensely.

CONCLUSION

During the whole of the day, I made it particularly plain that the towing art is extremely easy, yet very finely tuned; and that on no account would the information and demonstrations given be sufficient for any of the members present to proceed with towing themselves. It is extremely important to be taught thoroughly on the subject because of its apparent ease and obvious dangers.

For this reason it is of paramount importance for a school of towing to have had the opportunity to discuss and liais with current manufacturers of hang gliders in order to produce safer and better equipment and knowledge.

As a result of the demo and trial, Ian and I discussed the possibilities of reducing some causes of weak link breaks - namely the "gusting and pitching up phenomenon", a subject currently being worked on.

On a lighter note, there will be a new Clubman in Norfolk by the end of the month.
*
1984/09-07

THE 1984-85 FLATLANDS HANG GLIDING CROSS COUNTRY CHALLENGE

Denis Cummings
Singleton, AUSTRALIA

Between December 22nd, 1984, and January 6th, 1985, there will be a tow-launched hang gliding contest in the flatlands of central New South Wales, Australia.

An excellent site has now been found for the contest, situated midway between Parkes and Forbes in the center of N.S.W. We have two large wheat fields and a woolshed available to us for the duration of the practice days and contest.

Each field is over 1 mile long and 1/2 mile wide - on bearing North/South, the other East/West. There is a 1 km long strip near the woolshed - the strip is even lit. But we won't need that, will we?

The landowner has invited us to camp in or around the woolshed if we wish. It should be plenty big enough for the pilots briefing, seminars, partying, etc.. Power, water and toilets are available. Showers could be a problem, but there is a big farm dam nearby which should lay the dust and sweat.

The paddocks will be wheat stubble, but shall be slashed to suit our needs.

For those who require a more comfortable night's sleep, there are plenty of pubs, motels, caravan parks, cafes and clubs, etc., etc., at both Parkes and Forbes (both populations about 9000), about 20 km away by road.

The site is in an area of excellent thermal soaring activity. Two sailplane (glider) clubs operate near the site and achieve remarkable cross country flights.

Launch will be by both car towing and powered hang glider (trike) towing, and by any other method approved by the contest organizers.

The site is on a wheat property between Forbes and Parkes, New South Wales. Unobstructed flatlands prevail over most of the area within 150 to 300 kilometers.

"The 1984/1985 Flatlands Hang Gliding Cross Country Challenge" will use the following format:-

Practice Days and Seminars:
Dec. 22nd - Dec. 26th.

Contest Days:
Dec. 27th - Dec. 31st. and
Jan. 2nd - Jan. 6th

Open Day (Recovery!!):
Jan. 1st.

Light Wind Days:
Race - Out and Return
Race - Triangle

Medium to Strong Wind Days:
Race - To Goal
Distance - Goal Plus Distance
Distance - Open Distance

Two contest levels will be run, one for Advanced pilots, and one for Intermediate pilots. In addition, seminars on towing techniques, meterology, contest skills, safety etc. are planned.

International pilots are invited to participate. Contact:

Contest Organiser
Denis Cummings
16 Rawcliffe Street
Singleton NSW
AUSTRALIA 2330
Phone 065-724747
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1984/09-08

AUSTRALIAN UPDATE

Denis Cummings
Singleton, AUSTRALIA

Sorry I haven't been contributing anything lately, but I've been busy in Oz, trying to organize a major towing comp. Things look pretty good for the comp. now, as I've found a good site in the right area of Australia. (See related article in this issue of SKYTING.)

Over here (or "Down Under" if you like) we are doing a lot of car towing, and in this area (Newcastle/hunter Valley) we are doing a lot of trike towing. The methods are developing with very little change over those I've read in your magazine. If anything dramatic happens, I'll let you know.

P.S. By the time you get this, I'll have a new address - complete with towing strip.
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1984/09-09

SKYTING SAFETY RULES

Doug Gordon
Arizona Windsports
Tempe, Arizona

SKYTING is a form of Hang Gliding in which the glider and pilot are towed to altitude in a way which distributes the towline forces between pilot and glider proportional to the masses of each. The net effect is that 2/3 of the pull is on the pilot and 1/3 on the glider. The 3 factors of tow line tension are: vehicle speed; wind speed; glider pitch. These 3 factors are reflected as one figure on the tension gauge dial which the tow vehicle driver reads as he tows you. If the tension increases too much the driver lets up on the gas. A weak link is employed on the line as a fail safe.

THE 8 SKYTING CRITERIA ELEMENTS:

1. CONSTANT DIRECTION: Skyter sidesteps glider directly behind vehicle pull direction (into wind).

2. CONSTANT TENSION: Vehicle driver watches tension dial for constant pull.

3. PROPORTIONAL DISTRIBUTION: Skyting bridle solves this as mentioned above.

4. ATTACHMENT POINTS: The keel ring and body ring should be located as close as possible to the center of masses of the glider and pilot, respectively. I.e. control bar bracket; waist of pilot.

5. SLOW TRANSITIONS: Use 300 ft of elastic tow line (100% nylon) to stretch in order to guarantee that the towline tension always varies slowly.

6. RELIABLE RELEASE: 3-ring release works even as tension increases.

7. WEAK LINK: This is essential for towing so G-forces cannot build up under ANY circumstances. Remember "Murphey's Law. 200 pound test max.

8. SAFE LEARNING METHOD: Become expert in low and high winds at a LOW altitude before flying higher. Don't teach beginners Hang Gliding by towing.

SKYTING SAFETY RULES:

A. CONNECTIONS

1. Hook up - Hang check - Helmet on tight.

2. Rope straight to vehicle - Hook up bridle to release.

3. Hand into ripcord - Topline clear of helmet.

4. Pilot pulls back for tight line and sidesteps in line with vehicle/wind.

5. Launch Director rechecks Hook in/ Bridle/ Tow line/ Wind direction.

B. VERBAL TO PILOT BY LAUNCH DIRECTOR:

1. Keep the nose positive.

2. Keep wings level as you run.

3. Pull in as you lift off. As you go higher pull in harder! (Wind Gradient).

4. Keep glider directly behind vehicle.

5. Try to relax and think airspeed (i.e. pull in).

6. Pull in THEN release. (Your body should be through control bar as you release.)

7. Keep bar pulled in for a moment to pick up airspeed after release.

BASIC SAFETY CONCEPTS:

1. DO NOT PUSH OUT AT ANY TIME WHILE GLIDER IS UNDER TOW!

2. Launch director signals driver to start. (Hand signal or radio.)

3. Always hold downtubes for takeoffs and landings (within 50 ft of ground).

4. No turns within 50 ft of ground - watch windsock.

5. Fly faster as you near the ground - 20 ft. (Wind gradient.)

6. Relax - Make small, smooth control inputs.

7. Think airspeed - Keep that bar pulled in.

8. If you want to go higher - simply pull in less hard.

9. Do not practice flying skills while under tow. Keep glider behind vehicle and in constant tow force. (SKYTING IS A NECESSARY EVIL TO GAIN ALTITUDE ONLY.)

10. The idea is to be able to release or at least be able to slacken towline the instant the pilot wants to. Therefore:

a. Do not tow up past a 45 degree angle. (If vehicle stops, towline slackens.)

b. Keep glider behind vehicle. (By pulling in, pilot slackens towline.)

11. Even if weak link or towline breaks - pilot still must release his end!

12. Towline touches glider wire - Do not release yet. (Possible tangle).

13. SKYTING bridle: towline to apex ring/ Bridle tied to apex ring then passes through body ring then back to and through apex ring then up to and tied to keel ring.

14. Apex ring is large ring on release. Bridle: 20 ft of 5 or 7 mm perlon rope.

15. Use wheels! Walk glider back on/ saves bad takeoff. (Build from plywood.)

16. If release won't release - or line tangles - use voice activated RADIO to signal driver. Drivers radio set "push to talk".

17. HAVE FUN!
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1984/09-10

MORE FROM ENGLAND

Rona and Tony Webb
Norfolk, England

Concerning the subject of the threaded bridle end whipping and slapping pilot, I found that this does not happen with our short threaded bridle design. (See SKYTING No. 27.) (Actually these findings are not conclusive since we have had only about 100 flights on the design.) The end arches downwind and shortens as it travels. I have had a thump or two on the underside of my harness, but by shortening the necessary overall length of the threader due to the tow leg, it does reduce the effect.

I have released under extreme (150 lb) tension and under slack line conditions. Under tension it is swift to say the least. When it's slack, it sometimes lodges on the umbillical ring but a few wiggles on the cord soon releases this. When I say "lodge" this is all it is. The reason being that when using plait rope it is difficult to make a loop without lumps while supplying the necessary strength. I had simply hand-sewn a small loop, bound it tightly, and sleeved it in heat shrink plastic. The stiffness of the heat shrink is enough to lodge on the ring. We use larger 50 mm steel rings now, as this seems to improve performance. The loop on the end of the thread should be bound in thread. I am thinking about a sewn loop such as that shown in the drawing.

The helicopter net drop release is simple, a military designed quick release. It is hardy and reliable - operated by a Bowden cable system. It operates under load conditions and slack conditions. It ejects as well as releases.

Another idea we are working on deals with the subject of being gusted nose up in stronger wind conditions. This is uncomfortable, resulting in a pilot through the bar position. It has happened a couple of times to myself and to my colleague Phillip. (Incidentally, he is an experienced pilot who's never flown a hill ridge or any bump in the terrain.) So to reduce this phenomenon, we have considered a modification at the glider tow point: a spring loaded roller. This allows the tow position to move forward thereby decreasing the pitch-up mode and aiding decreased angle of attack under those conditions. The concept does make sense as mentioned in Skyting two verses back on adjustment of tow point for varying wind conditions.
+
The aim is to arrive at a Strong smooth flexible loop.
Plait Rope
(Climbing Perlin?
Neatly treated end.
Sewn loop threaded back inside rope and bound tightly.
Binding cord.
+
Threader
Header non stretch Part of Tow line.
2" Steel Ring.
Loop attached to Ring.
Threader.
Smooth loop.
+
3000 ft Main Line.
100 m. Stretcher
Inline Drouge Shute
Weaklink
Non Stretch Head.
Ring
Threader
+
Closed
Anchor Point
Release lever.
+
Open
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