Pitcairn PA-34

Pitcairn PA-33 / PA-34
	A still of a Pitcairn PA-34 Autogiro from a film clip of the aircraft flying circa 1930s.
Role	reconnaissance autogyro
National origin	United States
Manufacturer	Pitcairn
First flight	1936
Number built	1 x PA-34, 1x PA-33

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.

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

^ ^a ^b ^c ^d ^e ^f ^g Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's all the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. p. 279c.
^ "ASN Wikibase Occurrence # 120913". Aviation Safety Network. Retrieved 1 September 2017.

[JAWA38-1] ^ ^a ^b ^c ^d ^e ^f ^g Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's all the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. p. 279c.

[asn#120913-2] "ASN Wikibase Occurrence # 120913". Aviation Safety Network. Retrieved 1 September 2017.

[1]

[2]