The U-2 Experimental Category Motor Glider, deisgned by Don Mitchell, was first flown in 1980. It became at that time, and remains today, the highest performing aircraft of all lightweight, inexpensive motor gliders.The Mitchell-designed innovation he called Stabilators are upside-down airfoils that hang slightly below the trailing wing edges. They provide downloading for pitch stability and double as combination elevators for pitch and ailerons for roll control. The stabilators are manipulated by the stick through a mixer box using pull rods housed inside channels where the outer wing panels meet the main section when they are in the unfolded position.
The rudders, each upright on their respective wingtip, swing outward for directional control and combined with the stabilators, provide the same three-axis control as a conventional aircraft.
The U-2 is comfortable in front of a 20 horse power engine and together they weigh in at just over 300 lbs. But if higher performance is a goal, this aicraft can certainly entertain larger engines. Design features provide a stress factor of +/- 6 G's. Electric start and foldable prop can be added to make the U-2 a truly remarkable soaring machine.
Because of its clean aerodynamic design, the U-2 easily cruises at 65-70 mph with less than 2 gal/hr gas consumption. Aviation Week and Space Technology Magazine pointed out the B-2 Flying Wing Bomber was between 7-29% more efficient than the B-1 Bomber, which had a more conventional design. So there is no question that an all-wing design easily outperforms a comparable conventional aircraft.
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