Before Igor Sikorsky ever built a large helicopter, Frank Nicholas Piasecki delivered his first Flying Banana to the US Navy on September 12, 1947 -when he was only twenty-seven years old. The helicopter was the Piasecki HRP-1 Rescuer. Where Sikorsky's helicopters could rescue just one man, Piasecki's could retrieve ten at one time.

Originally nicknamed "the dogship" because it was a test vehicle, the U.S. Navy designated the PV-3 the XHRP-X (Experimental Helicopter, Transport), and the official Navy prototypes were designated XHRP-1. Then the aircraft was nicknamed "flying banana," which stuck to the HRPs as well as the later H-21 series.

The XHRP-X had a lightweight, steel-tube truss frame, with a fixed tricycle landing gear. The pilot occupied the front seat of the two tandem seats for the crew. At first, the pilots were protected by a Plexiglas windscreen. Later, a fabric covering increased the forward speed and enclosed the crew. A single Continental R-975 engine, located in an aft compartment, powered the two three-bladed rotors of the helicopter.

As the first man to manufacture large helicopters, it was Frank Piasecki who showed the world what they could do. The HRP-1 made it possible to bypass traditional beach defenses. Thus was born the USMC concept of vertical envelopment, upon which the Army would later base its similar doctrine of airmobility.