by George Wolfe Operations |
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"My first Spratt Controlwing Flying Boat" Collection of George Wolfe, 8-21-07 |
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In flight, both hinged parasol wing panels collectively and aerodynamically maintain a relatively constant angle of attack with a variable angle of incidence in reference to the hull. The NACA 23112 reflex airfoil was selected due to its favorable aerodynamic pitch response and small excursion of the lift vector. The wing panels are moved differentially to provide a very gentle bank and turn. The wide fixed vee shaped tail has no movable surfaces. It only guides the aircraft like feathers on an arrow and provides tail lift at cruise and higher power settings. Flight controls consisted of a throttle, steering wheel and an auxiliary pitch stick. Since the inherently stable Controlwing flying boat has no conventional ailerons, rudder or elevator, pilot control coordination is not required like in other aircraft. Conventional aircraft which can stall, spin and dive use those movable surfaces to direct an aircraft in pitch, roll, yaw and maneuvers about the CG. The steering wheel of the Controlwing only controls the differential angle between wing panels to provide a gentle bank and turn in the air and move the very effective kick-up and retractable water rudder. There is no feedback or cross talk between the pilot's pitch and roll inputs or outputs with this very simplistic control system and the auxiliary pitch stick is only used when the pilot desires to shorten a takeoff, move above or below an existing stable flight path or glide path, or to flare for a smoother landing. The throttle, conveniently attached to the auxiliary pitch stick which is mounted low like in a helicopter, is the primary vertical flight control. Hands-off takeoffs and landings may be made solely by increasing or decreasing power. With higher power settings the flying boat hull will assume a relatively level attitude for takeoff and cruise flight. When power is reduced to idle, tail lift is reduced and the hull will assume a nose high attitude essential for a safe water landing and the angle of incidence of the wing panels will automatically be reduced to accommodate the stable glide path. No air rudder is needed for the flying boat since the small angular difference between the wing panels does not create adverse yaw. Fast, sharp turns can be made on the water due to the low center of gravity, wide hull and the lack of wing tip floats to trip over. A Controlwing flying boat banks into the turns like any motorboat and can pivot about a wingtip touching the water and it is relatively crosswind tolerant. With a very minimum of flight training, a novice could easily and safely fly a Controlwing flying boat. Any pilot could receive adequate flight instructions by telephone. These kinder, gentler and safer aircraft have no inherent spin or dive capability and when the stick remains unrestrained during flight through turbulence, the occupants will sense only about one quarter of the normal gust loads. The Controlwing flying boat is the safest, simplest, easiest to fly and most comfortable aircraft ever developed! Fly it yourself and you will believe it. George Spratt often asked, "Did you ever see a fixed wing bird"? To that I add, "Did you ever see a bird with a rudder...or a low wing?" Bill Wolfe 1520 W. Ash St., Rogers, AR 72758-5014 1(479) 621-5822 EAA # 5716 SAA # 1431 1(479) 621-5822 billwolfe1@sbcglobal.net Northwest Arkansas EAA Chapter 732 You may copy and re-distribute this information to any interested parties. |
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"My first Spratt Controlwing Flying Boat" Collection of George Wolfe, 8-21-07 |
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