Firestone XR-9

The Firestone XR-9, also known by the company designation Model 45, is 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.

Development 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)"Short Hop Helicopter". Popular Science, April 1946. was a design for a single-seat helicopter of pod-and-boom configuration.Andrade 1979, p. 171. 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,Merriam 2002, p. 64 and was renamed the Firestone Aircraft Company in 1946.Lambermont 1958

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 Lycoming engine. The prototype was demonstrated at the 1946 Cleveland National Air Races.<AAHS Journal, Winter 2003, p. 316. 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.

Variants Model 45B Unbuilt single-seat helicopter with three-bladed rotor, Army designation XR-9. Model 45C Unbuilt single-seat helicopter with two-bladed rotor, Army designation XR-9A. Model 45C (revised) Tandem two-seat helicopter powered by an Avco Lycoming O-290-7 engine and two-bladed rotor, one built as the XR-9B, later re-designated the XH-9B. Model 45D Side-by-side two-seat helicopter for civil market, one built. Model 50. Four-seat version, not built. XR-9 Army designation for the unbuilt Model 45B XR-9A Army designation for the unbuilt Model 45C XR-9B Army designation for the Model 45C (revised), later redesignated XH-9B XH-9B XR-9B re-designated in 1948.

Operators

United States Army Air Forces

Survivors

The sole Model 45D is on display (without blades installed) at the United States Army Aviation Museum at Fort Rucker, Alabama.

Specifications (XR-9B)

Firestone XR-9

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