Photo credit: Custer Research Foundation | HopFlyt
Willard Ray Custer filed patents in the 1920s for a wing shaped like a curved trough. A propeller sat inside that half-circle channel and forced air across the surface. The goal was simple. Lift should come from moving air over the wing, not from racing the entire aircraft down a long runway first. Early tests showed real promise for short takeoffs. One demonstration had a man jogging beside the plane as it lifted off. Another had the aircraft strapped down while the props alone raised it on the lift generated inside the channels. A few 1950s prototypes flew and performed well in wind-tunnel work. The design still faded. Airplanes of that era were heavy, low-speed control felt limited, and the concept never delivered reliable vertical takeoff on its own.