The Curtiss XA-4 was produced by fitting a 440 hp Pratt & Whitney R-1340-1 Wasp air cooled radial engine into A-3 airframe serial number 27-244. The XA-4 was delivered in December of 1927. The radial Wasp engine decreased the gross weight to 4113 pounds, but the improvement in performance was only marginal, and the radial-engined Falcon was not introduced onto the production line. The single XA-4 was scrapped in March of 1932 after having logged 327 hours in the air.
Engine: One 440 hp Pratt & Whitney R-1340-1 air-cooled radial engine.
Performance: Maximum speed 137.5 mph at sea level, Service ceiling
Dimensions: Wingspan 38 feet 0 inches, height 10 feet 6 inches, wing
area 353 square feet.
Weights: 4113 pounds gross,
Armament: Four forward-firing 0-30-inch machine guns, two in the
upper engine cowling and two the lower wings. A pair of flexible
0.30-inch machine guns were mounted in the rear cockpit. Up to 200
pounds of fragmentation bombs could be carried on underwing racks.
Alternatively, a 56-gallon auxiliary fuel tank could be carried behind
the tunnel radiator.