The Curtiss-Bleecker Helicopter was a prototype rotary wing aircraft with thrust distributed from a central mounted engine through shafts to propellers mounted on each of four rotor blades. Designed by Maitland B. Bleecker, his design was unique in that his four propellers did not have individual engines but were connected by gearing via a single, centrally mounted, Pratt and Whitney 420hp radial engine.
The Bleecker helicopter was constructed by Curtiss Wright for $250,000 over the course of four years. Each rotor blade, painted silver and yellow, had an individual propeller for thrust and a trailing control surface called a "stabovator" to change its pitch which when operated collectively, enabled the aircraft to rise or descend, and when operated differentially, to ensure stability.
The aircraft was controlled by a stick that operated similar to a conventional helicopter collective control. Yaw was controlled with a "Spin Vane" that used downwash from the rotor blades to pivot the aircraft with foot pedals. The landing gear consisted of three fixed wheels.
With first flight occurring in 1926, this helicopter did successfully perform a few "hops" inside the hangar where it had been constructed. However in 1929 testing on the Bleecker helicopter was stopped after the failure of a drive shaft component on a test flight and by 1933 the project was abandoned following unresolved vibration issues and its lack of stability.