Cockpit of Curtiss A-3B (probably S/N 30-1), taken May 27, 1930. Note the center (primary) panel has water and oil temp, engine rpm, oil and gasoline pressure gauges. The air speed gauge is located on the right side (secondary) panel. (U.S. Air Force photo)
The A-3B was a modified version of the Curtiss O-1E observation plane. Like the A-3, which was a modification of the O-1B design, there were only a few changes incorporated into the attack version design. The A-3B had two additional machine guns installed -- one in each lower mid-wing. The O-1E had two forward-firing machine guns mounted in the nose in front of the pilot and a flexible mount (Scarff ring), for the observer-gunner, with two .30-cal. Lewis guns -- the A-3B retained the standard O-1E armament. The -B model also had a 200-pound bomb capacity, and up to eight 25-pound fragmentation bombs could be carried in racks mounted on the lower wing, center section.
The A-3B had a number of airframe improvements, also. First, the landing gear had pneumatic shock absorbers (oleo struts). Next, balanced flight controls were added: Frise ailerons and horn elevators. Finally, the engine cowling was smoothed for better aerodynamic performance.
During the A-3B's service life, various improvements were incorporated into the operational aircraft. The most obvious change was the addition of a tail wheel to replace the original tail skid. Most A-3s assigned to attack squadrons were brought up to A-3B standards during the early 1930s.
The Curtiss A-3 Falcon series of aircraft were the only biplane attack aircraft ever used operationally by the Army Air Corps. The monoplane designs of the early 1930s, notably the Curtiss Shrike series of attack planes, quickly made the A-3 obsolete.
A few A-3s remained in service into the late 1930s serving in secondary roles. For example, A-3s were used for aerial photography missions (mapping, high-altitude movies, etc.)
Attack version of Curtiss O-1B
Dual-control A-3 conversion
Attack version of Curtiss O-1E
TECHNICAL NOTES: Armament: Six .30-cal. machine guns and provisions for up to 200 lbs. of bombs Engine: Curtiss D-12E (V-1150-5) of 435 hp Maximum speed: 140 mph (118 mph at 15,000 ft.) Cruising speed: 111 mph Range: Approx. 650 miles Service ceiling: 14,400 ft. Absolute ceiling: 17,000 ft. Span: 38 ft. 0 in. Length: 27 ft. 7 in. Height: 10 ft. 3 in. Weight: 4,476 lbs. gross weight Crew: Two (pilot, observer-gunner) Serial number: (A-3B): 30-1 to 30-28; 30-231 to 30-280; Curtiss Model 37H