Hughes XV-9A was an experimental American high-speed research helicopter developed in the 1960s to test "hot cycle" propulsion, a system that eliminated the need for a heavy gearbox and tail rotor. First flown on November 5, 1964, the aircraft proved the feasibility of the concept but was ultimately cancelled due to high noise levels and excessive fuel consumption Design and Propulsion The XV-9A, also known as the Hughes Model 385, used a unique tip-jet propulsion system to drive its three-blade

Hughes XH-17 "Flying Crane" was a massive experimental heavy-lift helicopter developed by the Hughes Aircraft Company in the early 1950s. It is most famous for holding the world record for the largest rotor system ever flown, featuring a two-bladed main rotor with a diameter of 134 feet (41 meters). Key Characteristics Design Purpose: Built for the U.S. Air Force to test the feasibility of lifting immense loads, such as tanks and artillery, by straddling them with its tall, spindly landing gear.