Always on the look out for the unusual and impressive late last year Al came across the Airworld ASK 21. Originally designed as a slope sorer or flat field thermal sorer the Airworld ASK fitted the criteria for Al’s aerobatic glider requirement. The only problem being how to get 7 meters and 50 lbs of glider airborne here in the UK. In mainland Europe huge and powerful tugs are in abundance. Here in the UK they are far more scarce. That’s how the idea of fitting a turbine came about.

Airworld made a custom carbon fiber mount that is attached by only the wing spar, thus allowing the entire turbine assembly to be removed in minuets. This enables the ASK to be returned to the normal glider format with ease. At the time of making the order Al also took the liberty of ordering a second identical model for his good friend and flying buddy Dave Stephens. Airworld constructed both models and delivered them in a ready to fly condition. Fitted with 8 High power Jr servos. All that was required upon delivery was fitment of the turbines, and of course both models needed to pass the LMA over 20 kg scheme.

The turbines chosen were the Jet Cat P-120’s Producing 26 lbs of static thrust. At take off this means that both ASK’s have only a ½ to 1 power to weight ratio. Which seems inadequate when compared to the usual 1-1 that some of our jets have. Anyone that has seen either of these gliders fly will I am sure confirm that they are anything but underpowered. A typical flight routine will see maneuvers such as loops, bunts, stall turns, wing overs , tight spiral circuits, rolls and multi point rolls performed. Basically some very un glider type hard aerobatics, just performed in a scale elegant glider type style.

What seems to surprise most people is how much punishment the wings will take on this model. It is rare to see the ASK’s wings in a unloaded state. They seem to spend most of their time in a positive or negative loaded state. Each wing consist of a foam core which is then laminated with a skin of carbon fiber. This is then covered in a balsa top skin which in turn is then finished in white Profilm. The end result is an incredibly stiff wing that seems to flex in all the right areas.