Training With Scooter Tow

or

The Portable Variable Height Training Hill

Dave Broyles © 1995

Many hang gliding schools in the US have found it very difficult to secure training sites which are usable in all of the various wind directions which are common where they teach. While hang waiting is a skill which all pilots need to become accomplished hang glider pilots, there are few schools which have had much financial success in teaching it.

A number of schools have therefore searched for ways around the problem. Giant fans and in-door flying sites, while a possibility in Japan, where the largest indoor skiing schools are, have been ruled out here because everytime anyone builds a giant domed building for flying, someone starts hosting football games in it.

Here in Texas, we had the Trinity River Levees to teach on, but they were a little too low and a little too steep. Further, we had to depend on the City of Dallas to keep it mowed. When, in 1993, I saw a motorscooter converted into a stationary winch, I adopted the idea and began using a stationary winch for training. By the fall of 1995, 90% of my training was done via the stationary winch. I found that my training was greatly improved. Students learned faster, had fewer injuries, and I could teach in any wind direction 1 mile from my house. Further, I found that I could move students from scooter tow training to either slope foot launch or platform tow launch with little difficulty.

I train with scooter tow, using a variation of the traditional foot launch training methods. Instead of using older design gliders for training, I use modern gliders, although this is probably not necessary. I have a field about 1500 ft. long, and I either place a parked car or an earth anchor at the upwind end of the field. To this, I attach a pulley. I place the scooter winch at the downwind end of the field, approximately next to the student. I then run the tow line from the scooter winch, through the pulley and back to the student. I usually, but not always teach with a radio receiver on the student. I try not to use the radio in a way that makes the student dependent on it, but instead use it to fine tune the student's skills and to offer the student instant praise and correction.

The student starts out in the traditional way, running on flat ground with the glider but without a harness. As soon as he or she gets familiar with running with a glider, the student dons a harness and then runs hooked in to the glider. At this point, the tow line is attached to the student via a single point tow bridle. The tow bridle and the tow rope are above the base tube of the control bar. Running with the tow rope attached gets the student used to following the tow line at launch and to releasing from the tow line at the end of the tow. When the student starts the run, only enough throttle is applied to keep the towline taut. As the student progresses, keeping the glider level and the angle of attack correct, following the tow line and releasing as he or she stops, I gradually start helping with the throttle. What happens is a smooth transition from running to launching. After a number of tows, the student is flying along the ground at an altitude of from one to five feet. The goal is to let the student fly the glider level along the ground neither popping up the nose at launch nor pulling in the control bar so that the speed of the tow necessary to keep the student from touching the ground does not becomes excessive. Further, the student should maintain directional control of the glider. If the student is not able to do all of these things, then the operator cuts the throttle and lets the student back to the ground. Generally, at first, the student cannot do all of these things together, but after a very few tows, the student co-ordinates all of the things at once. Gradually the distance of the tow is lengthened until the student may fly along the ground for a thousand feet no more than a few feet high.

After I am confident of the student's ability to fly the glider under tow a few feet from the ground, I gradually fly them a little higher, and let him/her release and fly down to land. At this point, the student has been landing by running the glider to a stop or rolling to a stop on the training wheels so I start teaching him/her a flair landing. As the student gets higher on each successive tow, I have him/her land straight ahead and work on a successful landing techinque. The landing techinque gives the student practice in feeling trim speed and pitch control.

As the student gains ability and confidence, I keep towing him/her higher. Once the student is high enough to do small turns, I have him/her do "S" turns and come down into the wind. When the student has reached this point, the demands of flying straight under tow have pretty much taught the student proper turn technique so I usually expect the student to have no trouble with making small turns. If the student cross controlled or habitually flew the glider too slow, these problems should have by now been corrected. If they have not, the turns generally pinpoint the problem and I can correct it here in the training process.

Once the student has shown solid ability to do gradually widening turns, I start towing him/her as high as possible. At this point, I encourage the student to push out during the tow to maximize altitude, warning that if the glider starts to be hard to hold in a straight line then he/she needs to speed up. Next, I have the student fly circuits. A circuit is a flight which has the student do a 180 degree turn downwind and then another into the wind, hopefully landing at the approximate place where he/she took off. I always have the student do the first circuit with a clear understanding of the minimum altitude at which the second turn should be performed. I make it clear that landing downwind on wheels is preferable to turning too low. I teach in large open fields with few obstructions and I usually do the circuit training under radio supervision. After this point, students start making very rapid progress.

About here in the training, I take the students to a training hill to have them demonstrate a slope launch. I have found that providing the student has been properly taught to launch using scooter tow, with a low throttle setting and running the glider off the ground, he/she has no problem performing a proper foot launch from a training hill. After the students demonstrate mastery of proper foot launch technique, I take them to a bigger hill where they have to do a more complicated flight plan and let them demonstrate to me that they can fly next to a mountain.

I also transition them to platform launch. One of the virtues of scooter tow, is that scooter tow students almost invaribly tow excellently from a platform. Whether or not the student may be already flying holding the base tube in free flight, the student's first tows from the platform are performed holding the downtubes and flying semi-upright as he/she learned to do scooter towing. There is always an instructor on the platform for the student's first flights and the instructor launches the student from the platform. The one difference is that the tow line and release are below the basetube, and the student needs to be reminded that less pushout is required to climb with the towline below the basetube than above it. Generally students adjust to this quickly, as they have been taught not to pushout aggressively while climbing under tow. At this point, the student is usually towed to about from 800 to 1000 ft. altitude. The students have flown dozens of circuits by this point, and this will be the normal flight plan once again. Once the student has made a few launchs from the platform, I have them switch to the base tube for climbing under tow. This is different from scooter tow, where I tell the students to remain upright and holding the downtubes throughout the whole tow. I caution them to switch back upright if they have trouble controlling the glider. After they climb to the top of tow on the base tube several times, I have them launch while holding the base tube and in prone position. As soon after this as they are comfortable releasing themselves, I have them doing this also. At this point, a qualified tow observer with a hook knife may ride the platform instead of an instructor.

Generally, some where along this point, the students will have completed their novice tests and acquired a novice rating with both tow and foot launch signoffs.

Particular points to emphasize during the training process are:

1. Train the student to run the glider off of the ground by making the student launch at a reduced throttle setting. If the student habitually runs until the glider flies off of the ground instead of just pushing out and going prone, the habits learned will promote a solid foot launch at the mountain. The scooter operator should reinforce this by cutting off the throttle if the pilot pops the nose up and goes prone without running. (At least until the student is very solid on foot launch. A full throttle launch only requires a few steps.)

2. Train the student to release when he/she is in difficulty. The operator can compensate for a failure to release in most situations, but the risk to the pilot is reduced if the tow line is dropped.

3. Train the student to never overfly the turn-around pulley under tow(or the scooter if no turn-around pulley is being used).

4. Use reliable releases. I have used both a 3 string release and a mechanical release (designed for use with aerotow) operated by a downtube mounted lever. Both work well, but I prefer the lever operated release as it allows the student to release without taking a hand from the control bar. Always double check the correct operation of the release before each flight.

5. The winch operator should have a hook knife at hand. The student should be attached to the tow line with a properly sized weak link. I use a single loop of 205 leachline with a weakening knot in it between the mechanical release and the tow ring. If using a three string release, I use a weaklink of the same strength but build into the release mechanism.

Operational notes:

I attach the release to tow loops at the waist of the harness. I don't generally use bridles that go around the pilot to the carabiner because for foot launch, they tend to pull the pilot up to the biner before launch and let the release move too far from the pilot thus requiring too long a release line. With the mechanical release, I have a simple piece of line going from one tow loop to the other. The mechanical release is attached to the line with a snap hook. This is so the pilot can unhook from the glider since the mechanical release must remain attached to the glider when the pilot unhooks.

I have tried using a Skyting bridle with scooter tow, but have found no necessity for it. I find that launches are easier and much more like a mountain launch with the assistance of a single point above-the-control-bar bridle. On the other hand, gliders that have a comfort bar or a speed bar tend not to climb well with a single point bridle. I recomend using a European over and under style tow system if you plan to tow a glider using a speed bar or if you plan to do recreational towing. This is where you have two releases one attached to the tow rope above the base tube for launch, and and the second attached to an extension to the tow line which passes loosely under the bar and which you tow from after the top release is released.

I use a round parachute on the end of the towline to mark the end of the towline and to keep the rope from falling into a pile at the pulley. I put a 25 ft. extension past the top of the towline canopy to keep it from interfering with the pilot at release.

For training in particular, I use a retreval winch. This is a small winch powered by a car battery used to bring the tow line back to the start location. I attach the string on the retreval winch to the bottom of the tow line canopy and am very careful not to let it tangle with the student at launch. Design of the winch is the subject of a whole article by itself so I won't give any detail here, but it's real advantage is to reduce the turnaround time between tows to about 2 minutes.


 

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