The PA-18 and PAA-1 (PA-20) looked very much alike. It was difficult in fact, unless someone was very familiar with each, to recognize the differences. A note to Aviation from Ed Rice, the Director of Public Information of the Pitcairn organization, says the PA-20 was built as a “companion model” to the PA-18. A decision was made to discontinue manufacture of the PA-20 about April 14, 1933 because of the sim-ilarity to the PA-18.
Construction of the fuselage was the same as all preceding Pitcairn Autogiros. An assortment of steel tube diameters and wall thicknesses were gas welded together. The sides and bottom of the fuselage were rounded out with wood fairing strips. The tail group was nearly identical to the PAA-1. The only noticeable difference was the shape of the auxiliary vertical fins. The wing was identical in construction de-tails to the PAA-1, the span was decreased and the chord increased. The ailerons stopped short on the fuselage end to permit the walkway to extend to the trailing edge. The main landing gear was a scaled-down PCA-2 landing gear. The tail gear was a small wheel with a rubber chord shock absorber. A Kinner R-5, 160 hp engine turned a fixed-pitch Curtiss-Reed metal propeller eight feet, four inches in diameter. A ground adjustable propeller was optional at an increase of five pounds. A “coupe top” was also optional. The rotor was identical to the PAA-1 (PA-20, PA-24) except that it was 40 feet in diameter. The rotor pylon was simplified to one fore and one aft member with wire bracing from the top of the pylon to the upper longerons.
Pitcairn PA-18 built about 1931 for the sportsman and private user. About 19 of these were built and sold seven or eight of these were recalled during WWII and rebuilt as PA-39. All but one of them were lost when their transport was sunk.
Approved Type Certificate No. 478 applied to serial numbers from G-62 up to those manufactured prior to 30 September 1939, when the Approval expired.
Engine: Kinner R-5, 160 hp
Prop: fixed pitch 2 blade
Gross wt: 1900 lbs
Empty wt: 1310 lb
Rotor dia: 40 ft
No of blades: 4
Fuel cap: 30 USG