The Spratt Controlwing 107 was an unorthodox controlwing flying boat designed in the United States in the 1960s and marketed for home building in the 1970s.
The aircraft featured a flat, speedboat-like[1] hull with a square bow and with tailfins blended into each side.[2] [3] The fins were angled to form a butterfly tail and included no moving surfaces.[3] [4] The wings were mounted on struts, parasol-style, and also contained no moving surfaces.[1] [4] [5] [6] Rather, each of the two wings could pivot independently to vary their angle of attack.[4] [6] The pilot and a single passenger sat side by side in an open cockpit with a converted marine outboard motor mounted behind them that drove a pusher propeller.[1] [4] The flight controls consisted of a helicopter-style collective that varied the angle of attack of both wings simultaneously,[4] [6] [7] and a control wheel that varied their angles of attack in relation to one another.[4] [6] [8] The hull was constructed from polyurethane foam and covered with fiberglass, and the wing panels were fiberglass throughout.[4]
Designer George Spratt claimed that the Model 107 could not stall or spin, and that it was 75% less affected by turbulence than a conventional airplane design. With friend Elliot Dalland, Spratt began construction of the prototype (registered N2236) in 1962.[1] During the 1970s, Spratt marketed plans for the Model 107 to homebuilders.[9]