Pitcairn PAA1. Note: Tin!skid, three strut rotor pylon (the other from the rotor.) Gom^' forward is rotor spin up shaft); landing gear shock strut upper end goes to an outrigger assembly ahead of the fixed wing leading edge. (Pitcairn Photo)
In 1930 when Pitcairn began production on the PCA-2 he was chided as well as applauded for the machine's performance. The inference was that, although the autogiro was a seeming success, it was large and expensive and required the services of a professional pilot.
This annoyed Pitcairn and he accepted Ihe challenge to produce a light autogiro which would be safe for the novice to fly.
The product was an aircraft which has been referred to as a scaled model of the PCA-2. To the critical eye it did not closely resemble the PCA-2. The gross weight and the engine power were approximately one half of the PCA-2 figures.
The first attempt at a light autogiro was a PAA-2 with a 120 hp in-line Martin Chevrolet air-cooled engine. This craft lacked performance and a Kinner B5 of 125 hp was substituted, This model became a PAA-1.
The Martin engine delivered 120 hp at 2100 rpm while the Kinner gave 125 hp with only 1925 rpm, permitting the use of an eight-foot diameter propeller instead of the seven foot, nine inch prop that the Martin could swing. This gave the Kinner powered combination more acceleration which was the most important action for an autogiro.
The construction of the fuselage was the same as the PCA-2, except of course smaller. It presented a rather slab-sided appearance because it wras so lightly faired to save weight. The turtle deck from the cockpit to the tail was the only part that was noticeably faired. The lower engine cowl which originally housed the in-line Martin engine angled up to meet the five-cylinder radial Kinner
The wing, as on the PCA-2, was made with box spars and built up ribs. Drag and anti-drag wires braced the wing internally. Light plywood covered the top and bottom leading edge back to the spar. The airfoil was a Goetingen 429 "modified." The wing was wire-braced to the fuselage and to the landing gear. The tail group originally resembled a scale model of the PCA-2, but additional dorsal and ventral fins had to be added to achieve satisfactory directional stability. These were installed above and below the horizontal stabilizer.
There is some confusion why the PAA-2
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