Hughes XV-9

The Hughes XV-9, company Model 385, was a one-off American high-speed research helicopter built under a United States Army contract to prove hot-cycle propulsion. Two General Electric YT64-GE-6 turbojets served as gas generators, and their exhaust was ducted through the rotor blades to nozzles at the tips. To keep costs down it combined the side-by-side cockpit of an OH-6A with the landing gear of a Sikorsky H-34. It first flew on 5 November 1964 at Hughes's Culver City, California facility and then went to Edwards Air Force Base, where the tests were satisfactory even though the machine was noisy and burned a lot of fuel. Hughes could not solve those problems and did not develop its pressure-jet systems further. The Army tests were completed in August 1965 and the helicopter was returned to Hughes.