North American O-47
The North American O-47 was designed as a corps and division observation aircraft, but ended up serving as a trainer and target tug during the Second World War.
The O-47 looked like a rather stubby version of the standard single engine light bombers of the period. It had a crew of three in an enclosed cockpit, with a glazed position in the base of the fuselage to give the observer a better view. The prototype was powered by a 850hp Wright Cyclone engine
It was much faster than the liaison aircraft that would soon replace it, but also required much more support and better airfields than the later ‘puddle jumpers’. It was a three-person, mid-wing monoplane, the result of a great deal of debate about the right number of men required in an observation aircraft.
The O-47 was procured in larger numbers than any observation aircraft since the First World War, with a total of 238 production aircraft built.
In September 1934 the board given the task of appraising the O-47 described it as meeting ‘the requirements for an observation airplane more fully than any hitherto submitted’, although without making it clear what those requirements actually were. This opinion was given before the prototype Model GA-15 made its maiden flight in mid 1935.
In February 1937 an order was placed for 109 O-47As, later expanded to 164 aircraft. It was followed by the O-47B, with a more powerful engine and more fuel, of which 74 were built. The O-47 entered service in 1937.
Early in 1938 the corps area commanders were ordered to conduct service tests of the Douglas O-46 and O-47 to see how they could cope when used from small, unimproved airfields under field service conditions. The aim was to investigate how much the increase in speed and complexity of these aircraft had reduced their ability to perform their roles. Thee tests were carried out by the 97th Observation Squadron during exercises at Pine Camp and Fort Dix. The commanding officer of the squadron reported that the speed of the two aircraft had ‘no adverse effect’ on their abilities, but Pine Camp had two surfaced runways and Fort Dix had an existing square grass airfield, 1,200ft by 1,200ft in size – both much better than the sort of fields that artillery liaison aircraft would soon be asked to operate from! The Fieseler Storch could land in 60ft and take off in just over 200ft.
By 1940 the O-47 no longer fitted the Army’s requirements for an observation aircraft. The newly published FM 1-5 ‘Employment of Aviation of the Army’ described observation and liaison aircraft as being able to fly at very low speeds and take off and land within small level areas. This fitted with the new Stinson O-49, which had yet to enter service, but didn’t describe the O-47. The fighting in the Low Countries and France in May-June 1940 also demonstrated that these larger observation aircraft were no longer suited to modern warfare, with its increased mobility. Even the O-49 turned out to be too large and complex, and much smaller aircraft, based on civilian light aircraft, would end up filling the observation role (the Taylorcraft L-2, Aeronca L-3 and Piper L-4, all known as the Grasshopper).
During the Second World War the O-47s were used as trainers and target tugs. The type also served with the Air National Guard. By the outbreak of war in 1939 the O-47 accounted for almost hard of all National Guard aircraft.
The O-47A was powered by the 975hp Cyclone engine.
The O-47B was powered by a 1,060hp Cyclone engine and carried more fuel.
Engine: Wright R-1820-49 radial engine
Span: 46ft 4in
Length: 33ft 3in
Height: 13ft 9in
Maximum take-off weight:
Max speed: 221mph
Service ceiling: 24,100ft
Range: 840 miles
Armament: One fixed forward firing machine gun