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Posted 12/30/2008 Printable Fact Sheet
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Douglas A-20
Douglas A-20. Note the turbosupercharger inlet on the outboard aft engine nacelle. (U.S. Air Force photo)
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The Douglas A-20 can trace its development back to the Douglas Model 7B. The Model 7B design began in the spring of 1936. The finished design was submitted to the Air Corps for evaluation in 1938, and a prototype construction contract was signed in the summer. The aircraft was completed and flew for the first time in late October 1938. The Air Corps decided not to purchase the aircraft for a variety of reasons, but primarily because of budget constraints in the isolationist era immediately preceding World War II.

Although the Army wasn't interested in producing the Model 7B in quantity, the French were and ordered 270 production aircraft under the designation DB-7. The DB-7 design was updated and the aircraft was built as DB-7A and DB-7B models. With the fall of France and Belgium (which also ordered DB-7s), undelivered aircraft were diverted, primarily to Great Britain. The aircraft were re-designated Boston I (DB-7), Boston II (DB-7A) and Boston III (DB-7B).

In late 1939, the Air Corps reversed its decision not to buy the DB-7 and placed an order for 63 aircraft based on the DB-7B design. Initially, the Air Corps wanted a high altitude attack bomber version so the design was modified for a turbosupercharged version of the Wright Cyclone radial engine. The large turbosupercharger air inlets were mounted on the aft outboard section of the engine nacelles and gave the aircraft -- designated A-20 -- a very distinctive appearance. Only the first A-20 on order was actually completed as designed. The Air Corps decided it didn't need a high altitude light attack bomber, but rather a low to medium altitude version, so the turbosupercharger was unnecessary and deleted from the design. The 62 aircraft remaining on contract were built as P-70s, A-20As or F-3 reconnaissance aircraft.

The sole A-20 built was plagued by engine cooling problems associated with the turbosupercharger system. After completion of flight testing, the turbosuperchargers were removed and the engines replaced with a different version of the Wright Cyclone radial engine. The aircraft was re-designated XP-70 and used for prototype testing of the P-70 night fighter version of the Havoc. 

The Douglas A-20 Havoc played an important role in the early part of WWII. Initially the aircraft attracted the interest of European nations, primarily France, as a fast modern attack plane. With the fall of France, many of the aircraft ordered were diverted to Great Britain. The Army Air Corps became interested in the aircraft in 1939 and went on to order more than 6,000 aircraft in seven production models: A-20A, B, C, G, H, J and K.

Many of the Air Corps A-20s were delivered as Lend-Lease aircraft with large numbers going to Great Britain and the Soviet Union. The A-20 remained in service with the Army Air Forces throughout WWII; however, the improved Douglas A-26 Invader gradually replaced the A-20 as the AAF's primary twin-engine attack aircraft.

Type Number built/
A-20 1 twin eng. light attack bomber

Armament: Designed for four forward-firing .30-cal. machine guns in fuselage blisters, two .30-cal. machine guns in a flexible dorsal position, one .30-cal. machine gun in a ventral position and two rearward-firing .30-cal. machine guns in the engine nacelles, plus provisions for 1,600 lbs. of bombs
Engines: Two Wright R-2600-7 turbosupercharged Cyclone radials of 1,700 hp each
Maximum speed: 385 mph
Cruising speed:
Approx. 300 mph
Range: 1,100 miles maximum ferry range
Service ceiling: 31,500 ft.
Span: 61 ft. 4 in.
Length: 47 ft. 7 in.
Height: 17 ft. 7 in.
Weight: Approx. 20,500 lbs. gross takeoff weight
Four (pilot, navigator, bombardier and gunner)
Serial number: 39-735 

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