Douglas XA-2

The Douglas XA-2 was an American prototype attack aircraft converted from a Douglas O-2 observation aircraft in the spring of 1926 by Douglas Aircraft. One O-2, serial number 25-380, kept its basic structure but received an inverted air-cooled Allison VG-1410 engine in place of the water-cooled Liberty and had its lower engine cowlings omitted for cooling air. It was more heavily armed than the O-2, with six forward-firing .30-caliber Browning machine guns, two Lewis guns for the observer-gunner and a small bomb load of 100 pounds. The XA-2 was evaluated against the Curtiss XA-3 and won the first competition, but the Army found the Liberty engine underpowered and in dwindling supply and ordered a second competition with Packard engines, which Curtiss won. Only one prototype was built and the type was not ordered into production.