The Loening PA-1 was the last fighter to be produced by the Loening company, and was an attempt to produce a successful biplane fighter after the failure of the Loening PW-2 monoplane.
The PA-1 was a conventional biplane design. It was a single-bay biplane with staggered wings of equal length. The wings were rectangular in shape, and the central section of the upper wing contained the fuel tank. The wings were thicker than was usual and some of the controls were installed in the upper wing cut-out, placing them just above the pilot's eye line.
The aircraft had an almost circular rudder with no fin, mounted on the rear end of the fuselage, which was moveable. The semi-circular horizontal stabilizer was mounted just in front of the join.
The PA-1 was armed with two 0.3in Vickers machine guns. It was powered by a Wright R-1 (R-1454) nine-cylinder air cooled engine, making it the first US Army aircraft to use an air cooled radial engine (earlier aircraft either used inline engines or rotary engines).
The PA-1 was slightly lighter than the monoplane PW-2, but despite have a more powerful engine was slightly slower. Two prototypes were ordered, although only one was completed. It was delivered without its engine in April 1922 and underwent Army tests after the arrival of the engine in July but the aircraft's performance wasn't good enough to warrant putting it into production. This was the Loening company's last fighter design, and instead it focused on amphibians, producing the first Loening COA-1 in 1923. This would go on to be the company's most successful military aircraft, serving with the Army as the Loening OA-1 and the Navy as the Loening OL.
Engine: Wright R-1 (R-1454) nine-cylinder radial engine
Length: 19ft 9in
Height: 8ft 8in
Empty Weight: 1,536lb
Loaded Weight: 2,463lb
Maximum Speed: 130mph at sea level
Climb rate: 7 minutes to 6,500ft
Guns: Two 0.3in Vickers machine guns