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North American O-47

The North American O-47 was an observation fixed-wing aircraft monoplane used by the United States Army Air Corps.

Design and development

The O-47 was developed as a replacement for the Thomas-Morse O-19 and Douglas O-38 observation biplanes. It was larger and heavier than most preceding observation aircraft and its crew of three sat in tandem under the long canopy. Windows in the deep belly overcame the obstacle that the wings presented to downward observation and photography. The design for the XO-47 prototype originated in 1934 with General Aviation, a subsidiary of North American Aviation, as the GA-15. The Air Corps ordered 174 O-47s in 1937 to 1938, 93 of which were assigned to National Guard units. In 1938, the Army ordered 74 O-47Bs with a redesigned engine cowling for better cooling, a more powerful engine, and improved radio equipment.

Training maneuvers in 1941 demonstrated the shortcomings of the O-47. Light airplanes proved more capable of operating with ground troops, while fighters and twin-engine bombers showed greater ability to perform recon and photo duties. Thus, O-47s during World War II, except for those caught at overseas bases by the Japanese attacks, were relegated to such duties as towing targets, coastal patrol, and anti-submarine patrol.

Variants

XO-47: one built, serial number 36-145 in Dundalk, Maryland, 850 hp (634 kW) Wright R-1820-41 engineO-47A: 164 built in Inglewood California, Wright R-1820-49 engineO-47B: 74 built, minor improvements and a 1,060 hp (790 kW) Wright R-1820-57 engine installed, plus an extra 50 gallon fuel tank