There are 4 different launch methods and 3 of them require teamwork. The one not requiring help is the self-launch motorglider. The other 3 are, the aerotow, the bungee (or is it bungy?) launch and the winch launch. Although at Strubby we don’t have an aeroplane to tow our gliders we do occasionally have a tug visit so we can stay current on aerotowing. The bungee launch is a scaled up version of how you used to launch model aircraft with an elastic band. However, with a full scale glider you will need a hill, a large elastic band; the bungee, an even number of people prepared to run down said hill holding the ends of the bungee and some wind blowing directly onto the hill. We don’t have a hill. Pity. So we use a winch.
The winch launch is suitable for most sites where a long enough runway is available. With a runway length of approximately three quarters of a mile a winch will easily launch gliders to over 1,200′ depending upon wind strength and direction. Ideally launching directly into the wind will give the highest launch but at most gliding sites the runway direction is fixed so crosswind launching is common, often resulting in not such a high launch. Crosswinds are not normally a problem as certain techniques are employed to cope with them but sometimes if the crosswind is very strong then launching cannot safely take place.
So how does it work? Essentially the winch cable is attached to the glider and pulled in at high speed. As the glider is pulled forward at speed the wings generate lift and the glider climbs. Simple.
Yes, it is simple but there are lots of clever evolved designs which over the years have made winch launching safe and efficient. Winch design is a massive subject which is constantly evolving and now encompasses electric winches. Too complicated to go into here so instead here’s a simplified description of the winch we use at Strubby. Our SupaCat winch has a 6 cylinder air cooled diesel engine, a torque converter between the engine and gearbox that controls which of the two drums, each carrying almost a mile of 5mm diameter steel cable, is driven. At the end of each cable is a parachute to control the descent of the cable once released from the glider, a 30′ long shock rope and a steel cable strop encased in a sturdy plastic tube joined by a weak link. The strop is quickly interchangeable so that the correct weak link matching the glider to be launched can be easily fitted.
In the unlikely event of the glider being unable to release the cable, the winch driver can operate a guillotine to cut the cable. As you can imagine no-one is allowed close to the winch whilst a launch takes place but it’s also important not to get too close to the machinery at any time. Watch the guillotine video to see why.
Winch launching is a relatively cheap method of launching gliders and at the Lincolnshire Gliding Club will cost members £10. Why not check out our website to book a trial lesson and experience it for yourself.
