The autogyro was a Spanish development by engineer Juan de la Cierva during the early part of the 1920s and was meant to produce an aircraft that was relatively safe to fly in low-speed, low-altitude envelopes. The design became a mix of fixed-wing aircraft and helicopter theories that included a basic open-air-cockpit fuselage equipped with a nose-mounted engine / propeller combination coupled with an overhead main rotor unit. The primary difference between a true helicopter and an autogyro, however, lay in the main rotor's unpowered nature: the onboard engine was used to drive a traditional propeller unit to obtain the needed forward thrust and the main rotor only coming into play once airflow over (and up through) the blades was sufficient (thus causing rotation and lift).
The Pitcairn Aircraft Company was founded in 1926 to manufacture such aircraft and it was headed by Harold F. Pitcairn. In 1928, he secured the rights to produce the Spanish-originated Cierva C.8W autogyro model and a holding company emerged the following year. In 1931, the PCA-2 was first-flown and became the first autogyro to be certified for commercial airspace flight in the United States. The type went on to become the focus of several record-breaking ventures regarding aircraft (as well as several notable failed attempts) including a successful cross-country flight by John Miller in his "Missing Link" PCA-2. 1931 also saw the Detroit News become the first American news organization to invest in the autogyro to help collect more dramatic overhead shots of a given story.
Initial production models were designated simply as PCA-2 and these carried the Wright R-975 (J6-9) radial piston engine of 330 horsepower. The PCA-3 followed as a one-off investment which switched to the Pratt & Whitney "Wasp Junior" air-cooled radial engine driving a 48-foot main rotor. The PA-21 was equipped with the Wright R-975-E2 engine instead. The United States Navy (USN) entertained the thought of operating autogyros in the shipborne reconnaissance role and contracted for two PCA-2 aircraft under the designation of OP-1. Trials were had in 1931 but the results did not warrant serial procurement of the type.
The PCA-2 had a traditional aircraft body (fuselage) with a crew of two seated in tandem in separate open-air cockpits. The fuselage held the traditional, and conventional, engine fit at the nose to drive a two-bladed wooden propeller unit in tractor ("puller") fashion. The wing mainplanes were low-mounted under the fuselage and set well-head of midships, completed with up-turned wingtips. Under each wing mainplane was seated fixed, wheeled main landing gear legs. The aft section of the fuselage was conventional in that it was tapered towards the rear of the aircraft and capped by a single vertical tailfin mated with low-mounted horizontal planes.
Over the top of the front cockpit was installed the main (unpowered) rotor atop a tubular tripod assembly. This was a four-bladed component designed to capture forward airflow over and upwards through the blades to produce lift (rotation being the visual effect). The intended result would be a low-flying, low-speed aircraft that was theoretically easier to handle and control for most pilots.
Dimensions of the end-product included a length of 23 feet and a wingspan of 30 feet. Empty weight was listed at 2,230lb against an MTOW of 3,000lb. Installed power (PCA-2) was a Wright R-975 (J6-9) 9-cylinder air-cooled radial piston engine developing 330 horsepower. Performance specs included a maximum speed of 18 miles per hour, a range out to 290 miles and a service ceiling of 15,010 feet.
Between twenty and thirty of these autogyros were completed by Pitcairn for their time in the air. The company, based out of Willow Grove, Pennsylvania, went defunct in 1948 but not before several name changes. Its OP-1, built in two examples during 1932, was the first autogyro to receive any real military interest but this project did not materialize into useful global sales so little was had from the endeavor.