The Hiller HJ-1 was a development of the earlier HJ-2 Hornet, which was the first ramjet-powered rotorcraft built by Hiller, first flying in 1950. Evaluated by the U.S. Army as theYH-32 and by the Navy as the HOE-1, this later Hiller design was conceived as a light observation helicopter with a crew of two and a very short range. No production resulted from the evaluation.

The Hornet's fuselage was composed of a steel tube framework and a fiberglass and plastic laminate skin which could be detached and re-installed in a few minutes. Main and tail rotors both had two blades and were of all-metal construction. The main rotor had one Hiller 8RJ2B ramjet at the tip of each blade for the main propulsion system, and an auxiliary gasoline engine could spin the rotor up to 50 rpm to enable the ramjet engine to function. The tail had two small horizontal stabilizers in an inverted V configuration, and the landing gear consisted of twin skids. Ordered in 1952, all 12 prototypes were delivered to the Army in 1956.

First Flight: 1950

Service Introduction: not operational