Firestone XR-9

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.

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) 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 hp 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.

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
 * 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 Novosel, Alabama.