The Douglas XA-2 was a prototype American attack aircraft that underwent conversion from a Douglas O-2 observation aircraft in the spring of 1926.
Only one prototype was constructed, and the type was not commissioned for production.
The modification of the aircraft for its new role as an attack aircraft was carried out on a single Douglas O-2, with serial number 25-380.
While the basic structure of the aircraft remained unchanged, several modifications were made to it.
To enhance its resilience to enemy attack, the water-cooled Liberty engine (V-1650) of the O-2 was replaced with an inverted air-cooled Allison VG-1410 engine.
The lower engine cowlings were removed to allow for more cooling airflow over the engine.
Furthermore, the A-2 was more heavily armed than the O-2, with six forward-firing .30-caliber Browning machine guns, two in the nose forward of the cockpit, and two each in the mid-upper and lower wings.
Two .30-caliber Lewis guns were mounted flexibly for use by the observer-gunner in the rear defence of the aircraft.
The aircraft also had the capacity for a small bomb load of 100 lb (45 kg).
The Douglas XA-2 was compared with the Curtiss XA-3, with the former winning the initial competition.
However, the Army realized that the Liberty engine was both underpowered and in dwindling supply, leading to a second competition being ordered with both models upgraded with Packard 1A-1500 engines.
The Curtiss aircraft won this time, becoming the U.S. Army Air Corps’ frontline attack aircraft (Curtiss A-3 Attack Falcon) from 1928 to 1935. Specifications Crew Two Length 29 ft 7 in (9.02 m) Wingspan 39 ft 8 in (12.09 m) Height 11 ft (3.4 m) Max take-off weight 4,985 lb (2,261 kg) Powerplant 1 × Allison VG-1410 inverted air-cooled V-12 piston engine, 433 hp (323 kW) Performance Maximum speed 130 mph (210 km/h, 110 kn) Cruise speed 100 mph (160 km/h, 87 kn) Range 400 mi (640 km, 350 nmi) Service ceiling 15,000 ft (4,600 m) Armament Guns 6 × forward firing .30-cal. (7.62 mm) Browning machine guns,
Two in the fuselage
One in each wing 2 × flexible .30-cal. Lewis machine guns Bombs Provision for 100 lb (45 kg) of bombs mounted on lower wing racks.
Sources McDonnell Douglas aircraft since 1920: Volume 2-René J Francillon. San Diego Air and Space Museum Archive. The National Museum of the U.S. Air Force.