Scooter Mania in the USA

Dave Broyles 1994

Scooter Mania. What a dumb name for an article. Next thing you know, people will be picking it up to read it, thinking that it will be a continuation of the old controversy between Mods and Rockers moved to the USA. Well, no such luck.

But there is an explanation for the name. I'm a former motorcycle racer, who when working on his old Triumph Bonneville, and not having a car, rode around an old Vespa motor scooter for transportation. After retiring from racing motorcycles due to old age, (I passed 30) I began flying and teaching hang gliding. As there are no mountains in north Central Texas, I started out towing, instead of flying from a hill. Because of previous sailplane experience, I was aware of the concept of the stationary winch, but stationary winches for hang gliders weren't happening in the states. One was developed in the '70s but it was expensive and never became popular. A few years back, I had a hang glider towing student from Sweden named Edvin Rudd, who had learned to fly in England with a stationary winch. From what he had told me about his learning experiences, I knew it was a viable method.

About that time, I attended a paraglider instructor clinic in Santa Barbara, California. A guy named Brian Dahl had a Yamaha Riva 125cc motorscooter at the clinic, which he had converted into a stationary winch. The scooter was technologically head and shoulders above my '59 Vespa. It had an automatic clutch and transmission with a single cylinder overhead cam 4 stroke engine. When Brian began towing the paragliders, it became increasingly obvious that in front of me was an idea who's time had come.

I saw a motorscooter converted to a stationary winch as a possible way to improve my training program. So after coming back from the instructors clinic, I started considering building my own "scooter tow" stationary winch. This turned out to be a project which took a number of months. After some difficulty, I acquired a Yamaha Riva 125 scooter. I focused on this model because I knew that it had worked in the prototype system I had seen in Santa Barbara, and I was more interested in having a working winch than in experimenting. I did some design work, so that the scooter faced towards the glider being towed rather than away from it as did the prototype system. After a while, I had a system ready to test.

Next, I had to resolve issues about how to launch the glider being towed. Foot launched towing had dropped in popularity in Texas with the advent of the payout winch and platform launch, but the original center-of-mass tow system using a v-bridle attached to the pilot and to the glider came from Texas and I considered that method for a while. I had also heard on the Internet about what I call the "European 2 bridle system" which actually consisted of using two ropes, one above the control bar to launch with, and another below the bar to climb with. So I decided to try the "European system" but without the lower rope. I just attached the rope directly to a release on the pilot, attached just above his hips and routed the rope through the control bar. This worked like magic. I also experimented with the v-bridle system, but soon dropped it in favor of the single rope above the control bar.

The final refinement was the use of a turnaround pulley for training. This is a pulley placed out in the distance so the scooter tow winch can be located near the student taking off. This eliminates the need for an operator located 1500 ft away from the student, and greatly improves the safety of stationary winch tow.

I was soon using a "scooter tow" system as the basis of my training program. This turned out to be a fortunate decision. The only training hill near me was fenced off by the city due to crime and trash dumping problems in the area. But, I was merrily training along with a scooter tow system and I had already quit using the local hill. I rapidly found that with the tow bridle attached just above the pilot's center-of-gravity, one could use the scooter tow system to simulate hill launch. Via that discovery, I became free of the need for a training hill, except in the final portion of the training program.

After three years of training with a "scooter tow" system I have found that training injuries are less frequent using the scooter tow system than training from a hill. As an added benefit, students progress faster. I also found that the motor scooter based stationary winch had some other advantages over the other types of tow systems I have used.

The reason why training is safer and quicker using the stationary winch is related to what I call the variable height training hill. I can provide a virtual training hill from 10 to 500 ft. tall all at the same spot with a stationary winch. With careful operation of the winch a beginner can fly for 1000 ft. no more than 5 ft. from the ground. If he begins to stray, or have problems, he can instantly be set on the ground on the control bar wheels. This provides an excellent level of safety. As the pilot gains skill, he can be towed gradually higher, until he is high enough to fly a pattern which brings him back to the takeoff spot. this can be done so that the pilot never has to confront a situation which is excessively intimidating. An added extra bonus is that once the pilot is flying patterns, he can practice spot landings easily, even 6 to 10 a lesson.

The motor scooter based stationary winch is particularly suitable for training because it has a centrifugal clutch and a variable speed transmission. These features provide a lot of torque for launches even with a rather small motor. Because everything is small and light, the throttle response is extremely rapid. Because of the centrifugal clutch, the winch can even temporarily act as a payout winch, letting rope out if a wind gust increases the tension. If a pilot gets into trouble, the operator can release the tension quickly by just throttling back. It is also extremely fuel efficient. Typically a scooter tow system can be run several days on less than 2 gallons of gas.

The original system was based on a Yamaha Riva 125. I have also tested systems based on a Riva 180, a Riva 200 and also a Honda Elite 250. These systems are much more powerful than the original system. If your goal is to tow tandems, or to tow large pilots, (over 220 lb.) Then you must tow with one of the larger motorscooters.

For recreational towing, the scooter tow system works well, but for high altitude tows and for step towing, much more rope is needed than for training, at least 5000 ft. This requires that the drum be filled with small diameter Spectra or Dyneema rather than larger rope because of the small size of the scooter tow drum.

The scooter tow system is exceedingly portable. The scooter can be mounted on a lightweight trailer, or the bed of a pickup truck, or simply ridden to the flying site and then anchored down and the rear wheel swapped for a winch drum.

WARNING: BORING TECHNICAL STUFF AHEAD:

How is a scooter tow system constructed? The scooters I have particular experience with are the Yamaha Riva 125, 180 and 200, and the Honda Elite 250. I have arranged all the same way. I get a spare rear wheel from a junkyard, and modify it to be a winch drum by welding plates on the sides. I make the diameter of the drum as large as the space will allow, which in the Riva 125 has proven to be 17 inches and on the bigger scooters about 18 inches. The width of the drum is about the same as the width of the tire to prevent interference with the brake and other parts of the scooter. It could be made wider, but the cost of the machine work and welding will be correspondingly greater.

The design for the rest of the system has changed since the original version in that the whole scooter is mounted on a moving frame on wheels. This allows the tow tension to be measured simply by restraining the scooter from moving with a tension gauge. The rope guide is located in the center in place of the front wheel. The scooter sits on the frame supported by the center stand and mounted with the front wheel axle to a bracket above the rope guide. Placing the rope guide at the front wheel provides several feet of distance between the winch drum and the guide which causes the rope to wind onto the drum relatively level.

The scooter on it's moving frame is mounted on a trailer with a hard, smooth bed for the wheels of the frame to roll on. There is a second rope guide on the trailer bed to insure that the rope force is parallel to the ground. The trailer is provided with a jack to make it level.

Technical considerations of building the wheel include that two of the scooter models have aluminum wheels while two have steel wheels. In either case, though it is not intuitively obvious, the rope being wound onto the drum at high tension creates a side load on the flanges of the drum that will distort them or rip them off, if they are not sturdy or strongly welded. I recommend 1/4" flanges of 6061-T6 for aluminum wheels or 1/8" sheet steel flanges for steel wheels. In either case, the flanges should be welded both inside the wheel and outside.

The rope guides have to be capable of rather high speed operation as the rope running through them at up to 40 mph can create rather high rpms. I made guides consisting of 4 rollers, 2 vertical and 2 horizontal, with sealed ball bearings in them. As it happened, I had a number of old 1" downtubes and cut them into rollers, with machined cavities on the end to fit bearings with a 7/8" OD and 3/8" ID bearing. I mounted them using common 3/8" bolts in a cut section of 4" square steel tubing with 1/4" wall thickness. These dimensions were selected primarily for ease of construction, and could be built of similar dimensions with metric components. The space between the rollers was 3/4" in order to make it easy to get the rope through the guide.

For rope, I have been using 3/16" Dacron. This works OK, but with a turnaround pulley, the rope is dragged on the ground a lot and the rope tends to abrade and break. I would probably recommend Spectra® or Dyneema® instead, as it's high price will probably be compensated for by it's longevity.

The cost to build a system is typically less than $2500 including the cost of a used scooter, rope and a trailer to mount it on and the cost for operation has been really reasonable.

End of boring technical stuff.

Although I primarily use the scooter tow system I have for training, my friends and I have done some recreational towing using a 1500 ft to 2000 ft space. I had a fun fly-in last summer where we had a combination cross country and spot landing contest for both hang gliders and paragliders. At this particular meet, paragliders won both events even though they had a handicap in the spot landing event and the hang gliders were handicapped in the cross country. This is not to say that scooter tow is better for paragliders than hang gliders. At a combination scooter tow and aerotow fly-in we had in October, the best flight of the day was not from aerotow, but from scooter tow. A Finnish pilot, Veli Virvel, flying a Predator 142 hang glider, towed up with scooter tow to about 600 ft, then thermalled out and stayed up for 2 hours. He might have stayed up longer, but we were under an airline approach path and he limited himself to about 4000 ft agl. My personal best flight from scooter tow was a 3000 ft altitude gain and an 8 mile cross country on a paraglider, however on the same day, a woman pilot, Lynda Wacht, also on a paraglider, went about 14 miles with a similar altitude gain. We both were flying under a Class B airspace and were limited to 4000 msl.

As an instructor, I teach towing with a platform launch using a payout winch, stationary winch towing using a scooter tow system and aerotowing using a Pterodactyl Ptug ultralight. Each of these has it's place. I have been surprised to find that the most interest and excitement has been generated by my scooter tow system. So for those who don't mind a construction project and want an inexpensive stationary winch, I highly recommend that you track down an old motorscooter and put one together. I don't think you will be disappointed.

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