An Auto Tow Odyssey
Snatching Yourself Airborne: An Auto Tow Odyssey
Imagine a world where the club towplane is parked. Maybe the annual from hell, maybe you can’t find qualified tailwheel pilots, perhaps flying is restricted due to Coronavirus. You can’t afford a motor glider. You keep watching great soaring days go by. Suddenly you remember a paragraph from the Glider Flying Handbook about auto towing. Is this your salvation? Perhaps, but it is not as simple as having your wife floor it down the runway to snatch you into the air. Here are a few common questions answered and things to think about before you start.
Required Equipment
First, you need as long of a runway as possible. Longer runways allow for higher launch heights. Longer runways also allow you to fly a less aggressive & therefore safer launch profile. Higher launches increase the chance that you can thermal away. John Campbell’s old notes on ground launching still apply. Calculate the launch height you can expect from the runway length you have.
Next, you’re going to need a long rope. John’s notes will help. Note there is an ideal rope length based on runway length and headwind. For our 7000’ runway, we usually use 2000’ of rope. In the old days, our club used WWII surplus tow target cable. It was armored, cheap, and plentiful. It was also really heavy and a pain to repair. Since I’ve been auto towing, we’ve been using 3/8” Polypropolene. 1/2” would do fine too. You can buy it in 1000’ spools. It is easy to splice & repair. On our fairly rough runway, we seem to get about 50 launches before the first break.
There Are Some “Gotchas”
If you are auto-launching a European glider, make sure that a proper weak link is installed between the car and the glider! The max strength is specified in the flight manual or TCDS (Type Certificate Data Sheets). That weak link is considered part of the glider structure when the manufacturer sets the maximum winch launch speed, so don’t skip it!
The car must have a release. Most solutions here involve building a release that slides into a 2” receiver hitch on the car. In my club, a member made a Schweizer-style release. Other solutions I’ve seen are literally a Schweizer or Tost release mounted to a receiver. Make sure the driver can release if needed. We have a long arm on the release with a parachute cord that goes up to the driver.
Obviously, the pilot needs to be trained and endorsed by a CFI-G for a Ground Launch Endorsement. While the FAA doesn’t require, it is a smart idea to make sure the driver gets some training too. It doesn’t take too many supervised launches to get a good feel for what the right drive profile is.
Signals will have to be established to communicate between the glider and car, on the ground, and during the launch. Having a good radio in the glider and car helps a lot. Extreme care is required on the ground. Do not hook the glider up unless the pilot is ready for the launch. Anyone who is not hooking up the rope should be well to the side of the glider. Be particularly careful about watching for traffic overhead. You are about to lift a rope 1000 feet or higher into the air.
Be Careful with 1000’ of Airborne Rope!
Dealing with the rope after the launch requires some thought too. How will the rope be stored? I don’t recommend a parachute on the rope for an auto tow; that will just cause the rope to blow further crosswind after the release. You’ll need to be careful about runway lights, fences, tree lines, and anything else alongside the runway.
How many Horsepower does the car need? Generally, more is better. The faster you get up to flying speed the sooner you can start climbing and the higher you will get. Everything is a tradeoff. My first auto tows were in a 2-33 behind an early 90’s Dodge Caravan with about 300K miles. Nothing happened too fast but it got us in the air. Our long runway made up for the difference. Lately, I’ve been launching behind my 3.6L Subaru Outback. With 256 HP it has more horsepower than our towplane and does a fine job.
With some training and planning ahead, you can gain more freedom in your flying by being able to auto tow. Beyond that, auto towing is plain FUN. We’ve always had a good time doing auto tow days, trading off flying, and driving. And nothing beats the feeling of thermalling away and having a great soaring flight after one.
Tony Condon has made 63 off airport landings all over the middle USA and at most of the sites where he’s competed. In his early days flying the Cherokee II he landed out a lot close to home, but after moving up to a Standard Cirrus, he now lands out further from home. He is the President of the Kansas Soaring Association and a Designated Pilot Examiner. He competed on the US Team in the 13.5 Meter Class in 2015 and 2017, but avoided landing in Eastern European Fields by flying a Silent 2 Electro.
