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Firestone XR-9

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1940s American experimental helicopter

XR-9

General information
Type	Utility helicopter
Manufacturer	Firestone Aircraft Company
Primary user	United States Army Air Forces
Number built	2
History
First flight	March 1946

TheFirestone XR-9, also known by the company designationModel 45, is a 1940sAmerican experimental helicopter built by theFirestone Aircraft Company for theUnited States Army Air Forces. Only two (the military XR-9B and one civil example) were built.

Development

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Originally developed byG & A Aircraft with the co-operation of the United States Army Air Forces' Air Technical Service Command, theG & A Model 45B (designatedXR-9Rotocycle by the Army)^[1] was a design for a single-seat helicopter of pod-and-boom configuration.^[2] 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.^[3] TheModel 45C (XR-9A) was the same helicopter with a two-bladed rotor. Neither of the two helicopters were built. G & A Aircraft was purchased byFirestone in 1943,^[3]and was renamed the Firestone Aircraft Company in 1946.^[4]

A revised two-seat design the revisedModel 45C (orXR-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,^[3] it was powered by an AvcoLycoming O-290-7 engine^[3] and first flew in March of that year.

A civil version, theModel 45D was also built and flown, in anticipation of a postwar boom in aircraft sales.^[3] 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.^[3] The prototype was demonstrated at the 1946 ClevelandNational Air Races.^[5] A four-seatModel 50, with twin tail rotors, was also projected,^[3] but the predicted sales boom did not materialise, and Firestone closed its aircraft manufacturing division.^[3]

Variants

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Model 45B: Unbuilt single-seat helicopter with three-bladed rotor, Army designationXR-9.
Model 45C: Unbuilt single-seat helicopter with two-bladed rotor, Army designationXR-9A.
Model 45C (revised): Tandem two-seat helicopter powered by anAvco Lycoming O-290-7 engine and two-bladed rotor, one built as theXR-9B, later re-designated theXH-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 redesignatedXH-9B
XH-9B: XR-9B re-designated in 1948.

Operators

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United States: United States Army Air Forces

Survivors

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Firestone Model 45D at theUnited States Army Aviation Museum

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

Specifications (XR-9B)

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Data from Jane's all the World's Aircraft 1947,^[6]^[7]

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)

References

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Notes

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^"Short Hop Helicopter".Popular Science, April 1946.
^Andrade 1979, p. 171.
^^a ^b ^c ^d ^e ^f ^g ^hMerriam 2002, p. 64
^Lambermont 1958
^<AAHS Journal, Winter 2003, p. 316.
^Bridgman, Leonard, ed. (1947).Jane's all the World's Aircraft 1947. London: Sampson Low, Marston & Co. pp. 230c=231c.
^The Illustrated Encyclopaedia of Aircraft. London: Orbis Publications.

Bibliography

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Andrade, John.U.S. Military Aircraft Designations and Serials since 1909. Hinckley, Leicastershire, UK: Midland Counties Publications, 1979.ISBN 0-904597-22-9.
TheIllustrated Encyclopedia of Aircraft (Part Work 1982–1985). London: Orbis Publishing, 1985.
Lambermont, Paul Marcel.Helicopters and Autogyros of the World. London: Cassell and Company Ltd, 1958. ASIN B0000CJYOA.
Merriam, Ray.World War II Journal #15: U.S. Warplanes of World War II, Volume 1. Bennington, Vermont: Merriam Press, 2002.ISBN 1-5763-8167-6.

External links

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Media related toFirestone XR-9 at Wikimedia Commons

United Stateshelicopter designations, Army/Air Force andTri-Service systems

Numerical sequence used by USAAC/USAAF/USAF 1941–present;U.S. Army 1948–1956 and 1962–present;U.S. Navy 1962–present

Army/Air Force sequence
(1941–1962)

Prefix R-, 1941–1948	R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R-10 R-11 R-12 R-13 R-14 R-15 R-16
Prefix H-, 1948–1962	H-5 H-6 H-9 H-10 H-11 H-12 H-13 H-13J H-15 H-16 H-17 H-18 H-19 H-20 H-21 H-22 H-23 H-24 H-25 H-26 H-27 H-28 H-29 H-30 H-31 H-32 H-33 H-34 H-35 H-36¹ H-37 H-38¹ H-39 H-40 H-41 H-42 H-43 H-44¹ H-45¹

Tri-Service sequence
(1962–present)

1962 redesignations	H-13 H-13F H-13J H-19 H-21 H-23 H-25 H-34 H-37 H-43
New designations	H-46 H-47 H-48 H-49 H-50 H-51 H-52 H-53 CH-53/E/K HH-53/MH-53 H-54 H-55 H-56 H-57 H-58 H-59 H-60 UH-60 SH-60 HH-60 MH-60 H-61 H-62 H-63 H-64 H-65 H-66² RAH-66 TH-66 H-67 H-68 H-69¹ H-70 H-71 H-72 H-73
Alternate sequence	H-1 AH-1/J/T/W/Z UH-1/N/Y H-2 H-2G H-3 CH-3/HH-3 SH-3 H-4 H-5 H-6 AH-6 MH-6 OH-6
Non-sequential	H-90 H-92 CH-92/VH-92 H-101 H-139