# 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) 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.

## 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

    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.

## Specifications (XR-9B)

Data from Jane's all the World's Aircraft 1947,
General characteristics
* Crew: 1
* Capacity: 1 pax
* Length: 27 ft 7 in (8.4 m)
* Height: 8 ft 6 in (2.6 m)
* Gross weight: 1,750 lb (794 kg)
* Fuel capacity: 25 US gal (21 imp gal; 95 L) 80 Octane fuel
* Powerplant: 1 × Lycoming O-290-7 4-cyl. horizontally-opposed air-cooled piston engine, 135 hp (101 kW)
* Main rotor diameter: 28 ft 0 in (8.53 m)
Performance
* Maximum speed: 100 mph (160 km/h, 87 kn)
* Cruise speed: 80 mph (130 km/h, 70 kn)
* Service ceiling: 10,000 ft (3,000 m)
* Rate of climb: 1,000 ft/min (5.1 m/s)