quinta-feira, 2 de novembro de 2017

Douglas O-46 Vigilant

Douglas O-46 (Photo: Wikipedia).
           Eager to maintain its position as the principal supplier of USAAC observation aircraft, the Douglas developed the design of a two-seater monoplane to replace the end-of-life bi-planes of the 1920s. Two XO-31 prototypes flew in January 1930, and they were followed by five Y1O-31A for in-service tests, ordered in mid-1931. These aircraft were received in 1933 under the designation Y1O-43 and differed considerably from the final configuration of the O-31, with new wing supports and a larger drift.

           They went into service as O-43 and the 24th cell was completed as the XO-46 prototype, with a radial engine instead of the V12 used from the start. Approved in the tests, an order was made of 71 O-46A standard, then increased by another 90 aircraft. The O-46A served on the USAAC observation squadrons until 1940, when most were transferred to National Guard reserve units.

           At least 11 O-46s flew overseas; Two were destroyed in the Japanese invasion at Clark Field in the Philippines on December 8, 1941. The Maryland National Guard operated the O-46A off the coast of New Jersey for anti-submarine service. The remainder was declared obsolete at the end of 1942 and after that it was mainly used in training functions. A proposed variant of a Wright R-1670-3 engine was given the designation O-48, but was not built.

           The only survivor of the time it's the O-46A (s / n 35-179) is currently at the National Museum of the United States Air Force at Wright-Patterson AFB, near Dayton, Ohio.

           On November 27, 1942, O-46A, 35-179, of the 81st Squadron, landed at Brooks Field, Harlingen, Texas. The O-46A suffered one incident and was abandoned in place. More than 20 years later, it was discovered by the Association of Old Airplanes with trees growing through its wings, in 1967, it was rescued and transported to Ottumwa, Iowa. The restoration was beyond the capacity of the organization, and in September 1970 it was replaced by a C-47 from the National Museum of the United States Air Force. The (then) Air Force Museum restored it at Purdue University, and put it on display in 1974, the only survivor of of more than 90 O-46 built.

General features

Length: 34 ft 6¾ in (10.54 m)
Overflight: 45 feet 9 in (13.94 m)
Height: 10 feet 8 ½ inches (3.25 m)
Wing area: 332 ft² (30.8 m²)
Weight: 4,776 lb (2,166 kg)
Weight loaded: 6,639 lb (3,011 kg)
Engine: 1 × Pratt & Whitney R-1535 -7 14 cylinder radial engine, 725 hp (541 kW).

Performance

Maximum speed: 200 mph (174 knots, 322 km / h)
Cruising speed: 171 mph (149 knots, 275 km / h)
Range: 435 miles (378 mi, 700 km)
Service ceiling: 7,350 m (24,150 ft)
Ascent rate: 1,765 ft / min (9.0 m / s)

Armament
2 × .30 cal (7.62 mm) Tanning samples (one wing mounted and one flexible).

Font: Airforce / Wikipedia. 

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