The Pitcairn PA-34 and Pitcairn PA-33, given the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

(USN) designation Pitcairn OP-2 and

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

(US Army) designation Pitcairn YG-2 respectively were

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmisher ...

autogyro An autogyro (from Greek and , "self-turning"), also known as a ''gyroplane'', is a type of rotorcraft that uses an unpowered rotor in free autorotation to develop lift. Forward thrust is provided independently, by an engine-driven propeller. Whi ...

s designed and built in 1936 for evaluation.

Design and development

The

Pitcairn Aircraft Company The Pitcairn Aircraft Company was an American aircraft manufacturer of light utility aircraft. An early proponent of the autogyro, the company, later known as the Autogiro Company of America among other names, remained in business until 1948. ...

built and developed auto-gyros under licence from the

Cierva Autogiro Company The Cierva Autogiro Company was a British firm established in 1926 to develop the autogyro. The company was set up to further the designs of Juan de la Cierva, a Spanish engineer and pilot, with the financial backing of James George Weir, a Scotti ...

, trading as the

Pitcairn-Cierva Autogiro Company The Pitcairn Aircraft Company was an American aircraft manufacturer of light utility aircraft. An early proponent of the autogyro, the company, later known as the Autogiro Company of America among other names, remained in business until 1948. ...

from the late 1920s. Interest in the auto-gyro by the USN resulted in the purchase of two

Pitcairn PCA-2 The Pitcairn PCA-2 was an autogyro (designated as "autogiro" by Pitcairn) developed in the United States in the early 1930s.Taylor 1989, p.735 It was Harold F. Pitcairn's first autogyro design to sell in quantity. It had a conventional design fo ...

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 Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the cou ...

from June 1932, with the

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combi ...

(USMC). 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 The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

longerons In engineering, a longeron and stringer is the load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...

. 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. 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. Power was supplied by a nose-mounted 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. 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.

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 The National Advisory Committee for Aeronautics (NACA) was a United States federal agency founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its assets ...

(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.

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)

References

{{USN observation aircraft 1930s United States military reconnaissance aircraft OP-2 Single-engined tractor autogyros Aircraft first flown in 1936