Surface towing for teaching

[deltaman]

Tad,
a friend teached hanggliding by scooter towing (hope it was in 2 points) and for the beginning, close to the ground, he set a bridle from the nose to the line as a pitch limiter but without release on it.
I start to think about it but I'm still confident in your arguments..

[deltaman]

His goal is to limit the student to push cause after that he said there is an oscillation hard to manage on tow side..

[Tad Eareckson]

I like the idea of scooter towing. I learned, flew, and taught on the dunes, worked with people and flew on training hills, and carried a lot of gliders for a lot of people back up the slopes. Huge cost in labor for airtime.

It sounds like your friend is adding a device to solve a problem which need not exist and creating a problem of a glider which can't be released from tow. And a guy whose glider I carried up the hill many scores of times died of that problem after just two career scooter tows.

And we need to control our tows and advance our students such that things NEVER get dangerously out of kilter. Steve Wendt has demonstrated that that's a pretty easy mission to accomplish - even using the total junk he calls a release system.

If we're going to be training people from Day One with a goal of aerotowing in mind we should be putting them on training gliders, prone harnesses, dollies, and the same two point systems we want for ourselves.

His goal is to limit the student to push...

I think the best way to accomplish that is to teach the student to not push inappropriately and not give him enough kinetic and/or potential energy to get in trouble until he's solid on that issue. Seems to me that a pitch limiter would just be masking the problem.

[deltaman]

Thanks answering
you said:

And a guy whose glider I carried up the hill many scores of times died of that problem after just two career scooter tows.

Could you tell me more, please ?..

Any comments on that :
http://www.youtube.com/watch?v=lt18jVpUNRQ

We can see that the rope on the nose is often tight, so it's a 2 points mode most of the time.
Do you think there will be a benefit to set a real 2 points, somewhere on the keel but backward the nose ?

[Tad Eareckson]

Could you tell me more, please ?

I could write a book. Everything rotten about hang gliding coming together at once.

1996/04/28 - Frank Sauber - 68 - Pacific Airwave Formula 144 - Taylor Farm, King George, Virginia - 38°15'40.63" N 077°13'27.38" W
- Chest, massive internal - Keel, kingpost, leading edges, nose plate, crossbar, battens, downtube, sail
- Novice rating for seven years, in the sport for 17 years but "still low airtime", prior towing experience and a tow signoff for platform

The pilot and tow operator (Santos Mendoza) were using an experimental stationary winch system with a motorcycle engine and a launch dolly for two hundred foot tows and landing practice in light conditions.

On the first tow a bicycle grip release was used and three tries were required before the glider released.

On the second tow a three-string release was used. The pilot also said that he wanted to remain lower. "At fifty feet Frank got into a left turn for reasons unknown. The operator thinks that Frank may have been reaching for the release. The turn went uncorrected until Frank was 180 degrees from his original flight path." At some point in the turn the operator reduced power. The glider crashed nose first at an extremely steep angle.

The operator grabbed his first aid kit and reached the victim 30 to 45 seconds later, not breathing and without a pulse. He was able to enlist the aid of another pilot and the two transported the victim to a fire station close by where professional EMT's took over. The pilot was pronounced dead at a local hospital.

The above information has been assembled from second and third-hand reports. An official accident report on this incident has not yet been received.

This incident involves many equipment questions, especially regarding the possible surplus power of the winch. Others have questioned the flight path, speculating that 150 to 200 feet is a low altitude to plan a release. Such an altitude gives little time for action in the event of a problem. One recommendation resulting from this incident is for the tow operator to be ready to cut a glider free from tow before it reaches an unrecoverable attitude.

And that fatality was the catalyst...

Steve Kinsley - 1996/05/09 15:50

Personal opinion. While I don't know the circumstances of Frank's death and I am not an awesome tow type dude, I think tow releases, all of them, stink on ice. Reason: You need two hands to drive a hang glider. You 'specially need two hands if it starts to turn on tow. If you let go to release, the glider can almost instantly assume a radical attitude. We need a release that is held in the mouth. A clothespin. Open your mouth and you're off.

...for the development...



...of your four-string release - the one that safety obsessed flight park professionals like Jim Rooney have worked so hard to keep grounded.

Any comments...

I think what they're doing is just fine. He's getting a lot of cheap, easy, safe practice and development of the muscle memory actions he needs to control and correct glider pitch and roll.

Do you think there will be a benefit to set a real 2 points...

Not for what they're doing. They're just restricting the glider to reasonable limits while he figures out up, down, left, and right.

[deltaman]

Except in this case:

The pilot and tow operator (Santos Mendoza) were using an experimental stationary winch system with a motorcycle engine and a launch dolly

Which kind of release (lanyard) would you use in a 2 points low angle school towing with a foot launch to allow a release at any time without missing the control of the glider ?

[Tad Eareckson]

My feeling is that we SHOULDN'T BE foot launch towing in training.

A student can learn everything he needs to about foot launching just by running the glider - preferably into a light smooth breeze - off tow on flat ground and working in a few mild turns to learn how to correct.

Then start launching him off a dolly with a good built in two point aerotow release system and keep him skimming.

When he's ready for the kind of altitude at which the aerotow bridle is problematic put him on a Koch two stage - which is the safest off the shelf release we have for that application.

Bear in mind that...

When WE'RE towing we're shooting for the most dangerous unstable conditions we can find and - with a bit of human error thrown into the mix - it's almost inevitable that we'll kill someone on the rare occasion for want of optimal equipment.

But for training we're shooting for conditions which are the polar opposite and - even with foot launching and the most shoddy of release equipment - you've got to try pretty hard to kill someone on a good scooter tow system.

Santos conned me into guinea pigging his Rube Goldberg system a couple of times - 1994/05/21 and 1994/07/09.

On the first version I foot launched using my trusty two to one Hewett bridle / "release" system.
The tow system was a continuous out and back loop with spur line coming off it and going to the glider. He had so much slippage and spring built in that he couldn't get me up beyond eight feet. I couldn't afford to let go to abort the tow and he kept pulling me along until the spur line and my bridle were pulled through the pulley. (But he was kind enough to pay for half my faired downtube.)

The second iteration, dolly launched, was doable but - with maybe a three hundred spur line coming off the loop - dangerous and after a day of working out bugs and heat exhaustion (literally) we got me up on a single flight to two hundred feet on a three-string platform tow bridle/release just before the Thunderstorm From Hell exploded on us.

After that my enthusiasm for both Santos and his project was pretty drained and I declined further invitations. And at some point between then and Frank's fatal early next season I heard about a female student and a broken arm.

When Frank was crashed I'm pretty sure he was dolly launching from next to the winch and connected directly to the towline (no spur) which was routed through a turnaround pulley.

Although Frank would've been OK if he had had a release which he could've made work when he needed it to, I think there were a couple of other issues ganging up on him pretty hard at the time: short towline and inability / failure to dump tension quickly and sufficiently.

[deltaman]

Hi,
Did you already see that:

http://www.youtube.com/watch?v=BfidzEZt2mE


There are 2 ropes tied parallel on both side of the hangglider and lying on the ground from start to the end. And 2 others from each corner of the hangglider (leading edge/crossbar) which slide with a pulley along the 2 first ropes respectively.

Ingenious to discover the activity..

[Tad Eareckson]

And here's how we do it in the US:

http://www.youtube.com/watch?v=Srb9CagnMno


Much better 'cause it's a simple system. Everybody knows that the more complexity you have in the system the more things there are that can go wrong in new and unforeseeable ways. Always best to stick with tried and true methods with very long track records. (Especially when you've got people of varying ages on the line.)

[miguel]

And here's how we do it in the US:

Much better 'cause it's a simple system. Everybody knows that the more complexity you have in the system the more things there are that can go wrong in new and unforeseeable ways. Always best to stick with tried and true methods with very long track records. (Especially when you've got people of varying ages on the line.)

That system looks like it was conceived after a serious bud and brew session. The landing looked painful.

What were all of the extra ropes in the Chinese system? It seemed like the pilot was a passenger and the glider was still in controlled flight.