Spratt Controlwing Flying Boat

Comments from Bill Wolfe (BillWolfe1@SBCglobal.net) regarding the Spratt Controlwing:

I first saw a demonstration and then flew a Spratt Controlwing flying boat prototype in 1969, immediately deciding it was the only type aircraft I would ever care to own.

Starting in 1895 Dr. George A. Spratt and later with his son George G. Spratt, experimented with and built a large number of successful gliders, flying boats, land planes and even a flying automobile as a joint venture with Bill Stout.  All were aimed toward stable aircraft and safer aircraft control systems, and all of them used control wings in some fashion. (The Climax, Sport Aviation and CC Historical Society articles summarize these many projects.) 

The Controlwing flying boat consists of a boat-like hull incorporating a fixed vee shape tail with a pusher prop nested close to the tail surfaces to act as a venturi to provide lift when under high power settIngs. The two separately hinged parasol wing panels are collectively, aerodynamically and automatically moved to maintain a relatively constant angle of attack in flight. This may be overruled by use of the auxiliary pitch stick to temporarily move above or below a stable flight path or nose high glide, to shorten a takeoff run or to flare for a smoother landing, both of which can be safely accomplished hands-off by power application alone.

The steering wheel moves the wing panels differentially to provide a gentle bank resulting in smooth turns and also steers a water rudder to enable fast turns on the water due to the wide hull, low CG and lack of outboard floats to trip over. There is no coordination required with this simplistic control system. The Controlwing is the safest aircraft In the world - a very docile aircraft, Inherently stable and with no stall, spin or dive capability. Only 1/4 of the normal G load is felt In turbulence as the hinged wing will automatically spill gusts if the stick is unrestrained.