The PA-2C was designed to be a vertical take-off aircraft capable of sustained, high-speed level flight (operating from aircraft carriers, cruisers, destroyers, and unprepared landing sites). Called the “RingWing”, it combined two ducted propellers that contained an integrated system of vanes to deflect the slip stream downwards, over 90 degrees from the centerline of the aircraft in hover flight. In forward flight, the vanes would be retracted allowing air flow directly aft for forward propulsion at high speeds with the airfoil area of the duct providing the wing lift.
| Type | “VTOL” Research Vehicle |
| Crew | 2 |
| Engine | (2) GE-YT-58 |
| Horsepower | 1050 Each |
| Prop Diameter | (2) Turbomeca Artouste IIC |
| Fuselage Length | 7.5 ft |
| Weight Empty | 4,700 lb |
| Useful Load | 3,070 lb |
| Speed | 260 mph |
The ducted props were interconnected with a shaft driving through a central
mix box to which two T-58 turbo-shaft engines were attached. The turbine
exhaust flow was utilized to provide part of the longitudinal and yaw control.
For STOL missions, additional wing area was attached to the outer diameter of
the ducts, allowing a larger useful load.
A full scale “Ring-Wing” 7.5 feet diameter propeller unit was ground tested and
a 1/4 scale test model of the PA-2C aircraft (was built and tested successfully)
in the David Taylor model basin wind tunnel. This Vectored Thrust Ducted
Propeller technology formed the basis of later Piasecki air vehicle designs.