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Firestone XR-9 / GA-45

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In 1943 Firestone absorbed G and A Aircraft of Pitcairn Field, Willow Grove, and this included the CG-4A, a troop-carrying glider, and the XO-61, a pusher-type autogyro. Between 1943 and 1945 the G and A was modified and developed into a dual tandem helicopter, the XR-9B.

G&A Aircraft had previously built six examples of the XO-61 two-seat gyroplane for the U.S. Army. This experience was applied to the design of a new helicopter for the U.S. Army, designated Model 45.

Conceived in 1943, the Model 45 was a conventional pod and boom helicopter with tandem seating, a fixed tricycle undercarriage and a three-blade main rotor. Completed in 1944 with co-operation from the Army Air Force's Air Technical Service Command, the main rotor had three blades (and a fixed-type head); the tail rotor was 1.98 metres in diameter.

The helicopter was made of welded steel tube covered with an alloy skin, while the tail boom had a balsa-wood core covered with alcad. For storage purposes this helicopter could be broken down into three parts: rotor blades, fuselage and boom assembly.
The prototype incorporated an experimental electro-hydraulic governor, which by acting on the simultaneous pitch control maintained a constant predetermined rotor speed, irrespective of the power used. With automatic assistance from this governor, the pilot could rise or descend vertically just by using his throttle.

The original Model 45B design used a 126hp XO-290-5 engine and the Model 45C (military XR-9A) was a development with a two-blade rotor. Neither of these were actually built and the prototype (which carried the identity 6001) was designated XR-9B and was fitted with a 135hp Lycoming O-290-5 engine.
Firestone also built a civil version, the Model 45D (NX58457), with side-by-side seating but development of helicopters was abandoned by Firestone in 1947.

XR-9B
Number of seats: 2
Engine: 1 x Lycoming O-290-7, 135hp
Rotor diameter: 8.53m
Length: 8.41m
Width at landing wheels: 2.74m
Height: 2.6m
Gross weight: 800kg
Cruising speed: 128km/h
Inclined climb: 305m/min
Absolute ceiling: 3050m
Range: 400km
 


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