The Firestone XR-9, also known by the company designation Model 45, was a 1940s American experimental helicopter built by the Firestone Aircraft Company for the United States Army Air Forces. Only two (the military XR-9B and one civil example) were built.
Originally developed by G & A Aircraft with the co-operation of the United States Army Air Forces' Air Technical Service Command, the G & A Model 45B (designated XR-9 Rotocycle by the Army) was a design for a single-seat helicopter of pod-and-boom configuration. It had a fixed tri-cycle landing gear and three-bladed main and tail rotors. Power would have been supplied by a 126 hp (94 kW) Avco Lycoming XO-290-5 engine. The Model 45C (XR-9A) was the same helicopter with a two-bladed rotor. Neither of the two helicopters were built. G & A Aircraft was purchased by Firestone in 1943, and was renamed the Firestone Aircraft Company in 1946.
A revised two-seat design the revised Model 45C (or XR-9B) was built with a three-bladed main rotor and two-seat in tandem. The first aircraft procured by the Army Air Forces in 1946, it was powered by an Avco Lycoming O-290-7 engine and first flew in March of that year.
A civil version, the Model 45D was also built and flown, in anticipation of a postwar boom in aircraft sales. This differed in having the two occupants side-by-side instead of Tandem as in the 45C, and was equipped with a 150 horsepower (110 kW) Lycoming engine. The prototype was demonstrated at the 1946 Cleveland National Air Races. A four-seat Model 50, with twin tail rotors, was also projected, but the predicted sales boom did not materialise, and Firestone closed its aircraft manufacturing division.
General characteristics:
- Crew: 2
- Length: 27 ft 0 in (8.23 m)
- Main rotor diameter: 28 ft 0 in (8.53 m)
- Height: 8 ft 6½ in (2.60 m)
- Gross weight: 1750 lb (794 kg)
- Powerplant: 1 × Avco Lycoming O-290-7 flat-four engine, 135 hp (101 kW) each
Performance:
- Cruise speed: 80 (approx) mph (129 (approx) km/h)
- Service ceiling: 10,000 ft (3050 m)