Spratt Model 107

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.^[2]

Controlwing 107[1]
Role	Sport flying boat
National origin	United States
Manufacturer	homebuilt
Designer	George Spratt
First flight	1967
Number built	60 sets of plans sold by 1977[2]

The aircraft featured a flat, speedboat-like^[3] hull with a square bow and with tailfins blended into each side.^[4][5] The fins were angled to form a butterfly tail and included no moving surfaces.^[5][6] The wings were mounted on struts, parasol-style, and also contained no moving surfaces.^[3][6][7][8] Rather, each of the two wings could pivot independently to vary their angle of attack.^[6][8] 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.^[3][6] The flight controls consisted of a helicopter-style collective that varied the angle of attack of both wings simultaneously,^[6][8][9] and a control wheel that varied their angles of attack in relation to one another.^[6][8][10] The hull was constructed from polyurethane foam and covered with fiberglass, and the wing panels were fiberglass throughout.^[6]

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.^[2] With friend Elliot Dalland, Spratt began construction of the prototype (registered N2236) in 1962.^[3] During the 1970s, Spratt marketed plans for the Model 107 to homebuilders.^[2][11]

Specifications (Controlwing 107)

Data from Markowski 1979, p.384

General characteristics

• Crew: one pilot
• Capacity: one passenger
• Length: 17 ft 0 in (5.18 m)
• Wingspan: 24 ft 0 in (7.32 m)
• Height: 5 ft 0 in (1.52 m)
• Wing area: 96 sq ft (8.9 m²)
• Empty weight: 500 lb (227 kg)
• Gross weight: 1,000 lb (454 kg)
• Powerplant: 1 × Mercury 800 converted marine engine , 80 hp (60 kW)

Performance

• Maximum speed: 98 mph (158 km/h, 85 kn)
• Service ceiling: 3,000 ft (910 m)
• Rate of climb: 800 ft/min (4.1 m/s)