The brainchild of Willard Custer, the channel wing aircraft, of which this is the first, provided STOL capabilities by forcing airflow over the wing channels. The arrangement was quite effective at low speeds, but high speed performance suffered.
Willard Custer conceived channel-wing aircraft as result of seeing the roof lifted off a barn during a high wind and carried a few hundred feet into a nearby field. Reasoned that wind created a negative pressure differential which produced a lifting force greater than weight of roof and forces holding it in place; concluded that high speed air moving over suitably shaped airfoil could produce similar effect. To determine most efficient airfoil, began experimenting by blowing air over various shapes. Semi- circular configuration showed greatest promise, decided to build airplane around channel wing design which had produced a static lift force of 8 pounds per engine horsepower; in motion, increased to 13 pounds per horsepower. Concluded that channel wing produced about one-third more lift per sq ft of wing area than conventional airfoil. NASM's CCW-1 was first of 4 channel-wing models eventually built. Initially flew with conventional outboard wing sections in place (as displayed), but were later removed and only channel sections of wings remained. Performance satisfactory even with 1 engine out; motion of air on dead side continued to produce enough lift to maintain control. Contra-rotating props enhanced lateral stability. Cross shafting between engines considered but never introduced. STOL characteristics excellent; takeoff required as little as 200 feet and plane could land at 36 mph. Prototype of final version, CCW-5, conversion of pusher Baumann Brigadier executive aircraft, flew 13 Jul 53; first production model rolled out 4 Jul 64. Despite remarkable low-speed handling and maneuvering qualities and interest of potential buyers, could not develop resources to go into production. By 1964, Beechcraft Bonanza had captured much business aircraft market and vertical performance of turbine-powered helicopters overshadowed short-field capabilities of channel wing. Later, Custer claimed the relative engine-to-wing placement on Republic (Fairchild) A-10 infringed on his patents but lost on grounds that both he and Republic had recognized similar airflow (natural) phenomena and incorporated them in their respective designs. Custer, a great grand-nephew of George Armstrong Custer, had been offered as much as $40 million for patents but refused, preferring to stay independent. Died in 1985. Son, Harold, accumulated over 1,000 hours of channel-wing flying time and continues to work on ultra- light, single-engine, channel-wing design and remains optimistic that channel- wing principle will reemerge in future aircraft designs.