The concept of a flying mock-up permitted a rapid demonstration of the unique configuration and a measurement of the XHRP-X flight and control characteristics. Early design improvements in the XHRP-1 prototype resulted.
| Mission | Transport, Crane, Tow, ASW |
| Crew | 2 |
| Passengers | 10 |
| Engine | P&W R-1340 |
| Horsepower | 600 |
| Rotor Diameter | 41 ft |
| Fuselage Length | 48 ft |
| Weight Empty | 5,041 ft |
| Useful Load | 1,859 lb |
| Maximum Speed | 103 mph |
| Cruising Speed | 86 mph |
| Range | 265 miles |
| Ceiling with Normal Load | 10,400 ft |
Twelve of the HRP-1’s were assigned to the Marine Corps to help develop vertical assault tactics during operations from the flight carrier Saipan and escort carrier Palau. Navy squadrons flew the HRP-1 until 1953, primarily in the development of antisubmarine warfare equipment and mine-sweeping experiments.
Twenty production HRP-1’s were delivered to the Navy and Coast Guard. It was nicknamed the “flying banana” because of the curve in the fuselage that provided rotor blade clearance. The HRP’s were found to be practical in many pioneering applications that today are standard military doctrine, including search and rescue, anti-submarine warfare, amphibious assault, heavy transport, and mine-sweeping.
