Aero Tow at Kirknewton Airfield – courtesy of Forth Valley Soarers
Alistair prepares the Greenley tug. It has no problems with any of the gliders we have tried so far. The biggest has been a Multiplex ASH26.
The gliders are fitted with a Picolario vario which gives real time altitude. Release is around 700ft giving 5 minute flights without thermals. With lift we have achieved flight times of 20 minutes.
In case the glider tow release fails the Greenley can also release the line. Alistair usually drops the line on the runway before landing to avoid draging the line over the rough tarmac.
The Ventus 2C is 1/5 scale, wing span 3.6m. It has a retract so can take off from the tarmac runway. Landing is usually with the wheel up on the grass.
We mostly use the Graupner tow release. It is simple to operate and reliable only requiring a standard servo. The tug throttles back at release to reduce the load just in case.
The Weihe 50 is from the Graupner kit. Span is 3.2m. It is very light and thermals with ease.
It has no wheel so it is towed off the grass while the tug runs on the tarmac. The glider is off the ground long before it reaches the tarmac. The tow release on the model is simply a solid pushrod over a hole in the bottom of the fuselage.
The Weihe 50 lifts off the grass after only a short drag along the grass. The Greenley is able to take this model to release height after only half a circuit.
We have had a problem with the low tow position causing the glider to roll when the line snatches after going slack in a turn. It is hoped a new more scale tow position in the nose will cure this.
The biggest and heaviest model we have tried so far is this Multiplex ASH26. Span is 4m, weight about 5kg. The Greenley tug hardly noticed the glider just requiring a slight trim change to reduce the climb rate.
Off the tow it flies well. On the first day aerobatics were performed several times before using thermals to climb over the initial launch height. A flight of over 20 minutes was achieved.