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The Pitcairn PA-34 and Pitcairn PA-33, given the United States Navy (USN) designation Pitcairn OP-2 and United States Army (US Army) designation Pitcairn YG-2 respectively were reconnaissance autogyros designed and built in 1936 for evaluation.

Pitcairn PA-33 / PA-34
The wreckage of the YG-2 after crashing on 20 March 1936
Role	reconnaissance autogyro Type of aircraft
National origin	United States
Manufacturer	Pitcairn
First flight	1936
Number built	1 x PA-34, 1x PA-33

Design and development

The Pitcairn Aircraft Company built and developed auto-gyros under licence from the Cierva Autogiro Company, trading as the Pitcairn-Cierva Autogiro Company from the late 1920s. Interest in the auto-gyro by the USN resulted in the purchase of two Pitcairn PCA-2 autogyros, modified as two-seat observation platforms, designated XOP-1. Trials with the XOP-1s from 1931 had limited success, but included an operational deployment in Nicaragua from June 1932, with the United States Marine Corps (USMC).[1]

Following the development of much-improved rotor and control systems, further interest by US armed forces resulted in the Pitcairn PA-33 (YG-2) and Pitcairn PA-34 (XOP-2). These essentially identical aircraft differed mainly in undercarriage design; the PA-33 had fully cantilevered oleo-pneumatic undercarriage legs and the PA-34 had strut mounted split axles with oleo-pneumatic shock-absorbers attached to the top fuselage longerons.[1]

The fuselage was constructed of welded steel tube with fabric covering and light alloy fairings. The 3-bladed folding rotor was mounted on a braced bi-pod with legs fore and aft of the front cockpit. The tail unit consisted of a very wide chord fin and rudder with a strut supported tail-plane sporting up-turned wing-tips. Tail surfaces were constructed of wood with fabric covering and rotor blades were built with steel tube spars and plywood ribs with fabric covering.[1]

Accommodation was in tandem cockpits with the pilot in the rear cockpit aft of the rotor support bi-pod and the observer in the front cockpit beneath the rotor head.[1]

Power was supplied by a nose-mounted 420 hp (310 kW) Wright R-975E-2 in a tight-fitting wide chord cowling with blisters to accommodate rocker arms. The engine was mounted with considerable nose-down angle to ensure prop-wash over the rotor to maintain rotation and ease rotor starting.[1]

Control of the aircraft was achieved only by use of the throttle and the tilting rotor-head, operated by a hanging control stick in the rear cockpit.[1]

Operational history

The YG-2 and OP-2 were briefly tested by the US Army and US Navy, with limited success. After completing tests with the US Army, the YG-2 was taken over by the National Advisory Committee for Aeronautics (NACA). registered as NACA 88. On 30 March 1936, whilst on test, NACA 88 suffered a rotor failure, prompting the crew to perform the first successful bail-out from a rotary-winged aircraft.[2]

Variants

PA-33

Company designation of the YG-2 for the US Army

PA-34

Company designation of the OP-2 for the US Navy

YG-2

US Army trials autogyro (PA-33), 1 built.

XOP-2

US Navy trials autogyro (PA-34), one built.

Specifications (PA-33 / PA-34)

Data from Jane's all the World's Aircraft 1938[1]

General characteristics

• Crew: 2
• Length: 43 ft 5 in (13.23 m) blades folded
• Width: 15 ft 0.1 in (4.575 m) blades folded
• Height: 11 ft 7 in (3.52 m)
• Empty weight: 2,300 lb (1,043 kg)
• Gross weight: 3,300 lb (1,497 kg)
• Fuel capacity: fuel 66 US gal (55 imp gal; 250 l); oil 6.5 US gal (5.4 imp gal; 25 l)
• Powerplant: 1 × Wright R-975E-2 9 cylinder air-cooled radial piston engine, 420 hp (310 kW)
• Main rotor diameter: 50 ft (15 m)
• Propellers: 2-bladed variable pitch metal propeller

Performance

• Maximum speed: 140 mph (230 km/h, 120 kn) at sea level, 128 mph (111 kn; 206 km/h) at 8,900 ft (2,700 m)
• Cruise speed: 115 mph (185 km/h, 100 kn) at sea level
• Minimum control speed: 22 mph (35 km/h, 19 kn)
• Endurance: 3.26 hours at cruising speed
• Service ceiling: 15,500 ft (4,700 m)
• Time to altitude: 5,000 ft (1,500 m) in 3.8 mins
• Take-off distance: 135 ft (41 m) in dead calm: 0 ft (0 m) in 28 mph (24 kn; 45 km/h) wind
• Landing run: 0 ft (0 m)

References

На других языках

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[de] Pitcairn PA-33

Die Pitcairn PA-33 war ein Tragschrauber des US-amerikanischen Herstellers Pitcairn Aircraft Company und wurde als YG-2 durch das United States Army Air Corps (USAAC) erprobt. Es wurden lediglich Prototypen hergestellt.

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- [en] Pitcairn PA-34

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[fr] Pitcairn PA-34

Les Pitcairn PA-34 et PA-33, recevant respectivement les désignations Pitcairn OP-2 — pour la United States Navy — et Pitcairn YG-2 — pour la United States Army —, étaient des autogires de reconnaissance américains, conçus et fabriqués en 1936 pour évaluation.

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