Douglas A-20 Havoc
The most important and famous Army attack-bomber of World War II was the Douglas A-20, winner of the 1939 competition. Its design was actually begun in 1936 at El Segundo as the Northrop 7A, before that organization became part of the Douglas company. That design was revised as the Douglas Model 7B for submission in the July 1938 attack-bomber design contest, and a prototype was constructed to compete for the 1939 production contract.
As first flown October 26, 1938, the 7B had two 1,100-hp Pratt & Whitney Twin Wasps, a shoulder-high wing, and the first tricycle landing gear on an American combat plane. This nose-wheel gear permitted faster landing speeds and thus a smaller wing, leading in turn to the highest speed of any contemporary American bomber.
For the low-level attack mission, the 7B had a metal-covered nose and could be armed with two .50-caliber and six .30-caliber fixed guns, 80 30-pound or 14 100-pound bombs. A different nose with Plexiglas windows for a bombardier allowed the use of one 2,000 or four 300-pound bombs, while retaining four .30-caliber fixed guns in blisters. Both versions were defended by a rear gunner with a retractable “birdcage” turret, and another .30-caliber gun to fire downwards from a retractable floor mount.
The first flights were not announced to the public, but a crash on January 23, 1939, brought the plane widespread controversial attention. It was discovered that a French officer had been aboard, in violation of the Air Corps policy of not releasing information on new aircraft types until they were approaching obsolescence. An investigation revealed that President Roosevelt himself had made the decision to allow France and Britain to buy up-to-date American warplanes, thus rejecting traditional isolationism.
France did order 100 Douglas DB-7s on February 15, 1939, and the first flew at El Segundo in only six months, on August 17, 1939, with 900-hp R-1830-SC3G Twin Wasps with 87-octane fuel and Hamilton propellers. Designer Edward Heinemann (1908-1991) provided the French with a transparent bombardier’s nose, engine nacelles lowered below the wings, intakes on the cowl tops, cockpit armor, and replaced the rear turret with a simple sliding canopy. Armament, to be fitted in France, included four 7.5-mm nose guns, a 7.5-mm upper rear gun, another for the ventral opening, and a choice of 64 22-pound, 16 110-pound, eight 220-pound, or four 440-pound bombs.
An additional 170 DB-7s were ordered October 14, 1939, and, beginning with DB-7 number 131, 1,000-hp
R-1830-S3C4-G Twin Wasps using 100-octane fuel were installed on the remainder of the 270 DB-7s completed by September 3, 1940. The 131st DB-7 had also been tested July 26, l940, with a twin rudder arrangement requested by the French, whose Leo 45 bomber was thought to have a better rear gunner’s fire field due to twin tails. This system was not adopted for production, however, for firepower, not field of fire, was the common weakness of bomber defense in those days.
Not until December 25, 1939, did ships carrying the first eight DB-7s arrive in Casablanca, where they were slowly assembled and delivered to the French air force in March 1940. By June 25, 121 arrived in crates, and 64 had reached five squadrons when the DB-7 entered combat on May 22. Fastest bombers at the front, they flew about 134 sorties, losing 16 DB-7s before France surrendered and the Douglas squadrons were withdrawn to North Africa. Britain took over all French contracts and 138 undelivered DB-7s on June 17.
The British named the earlier DB-7 Boston I, using four as trainers introducing nose-wheel gear to RAF pilots, and briefly called the 134 S3C4-G models the Boston II. Night operations had become a major RAF concern, so
the Bostons went to six Fighter Command Squadrons renamed the Havoc I (Intruder) with black paint, flame-damper exhausts, and four .303-caliber fixed guns to supplement the bomb load. As aircraft intercept (AI) radar became available, the Havoc I (Night Fighter) appeared with the bomber’s compartment replaced by four more guns in a solid nose fairing. Instead of guns, 21 Havocs fitted with a searchlight in the nose became the “Turbinlite’ version. (See Chapter 18 for details).
Britain also inherited a French contract made October 20, 1939, for 100 DB-7As with 1,275-hp R-2600-A5B Cyclones. With longer nacelles, armor, and broader vertical tail, the first DB-7A was flown on July 30, 1940, but crashed before acceptance. The remainder were accepted from November 20, 1940, to February 13, 1941, and, less eight lost at sea, were converted in Britain to Havoc II night fighters with twelve .303-caliber nose guns, added fuel tanks, and AI Mk. IV radar, while 39 became Havoc II (Turbinlite).
Meanwhile, work on the Army version proceeded more slowly. The crashes of the 7B and NA-40 left the Stearman and Martin ships the only survivors of the March 38-385 competition. To these firms’ disappointment, no contract was awarded then; the Army instead waiting for new bids on April 17 for Circular Proposal
39-460, a modified specification not requiring prototypes.
Among the eight firms submitting new bids, Douglas offered a new version of their plane with Wright R-2600 engines instead of the R-1830 Wasps used on the 7B prototype. This won the order announced May 20, 1939, for 186 attack bombers, while only the prototypes of Stearman and Martin were purchased.
The first Army version was the A-20A, powered by Wright R-2600-11 Cyclones with a larger nose enclosure, stronger structure, and more fuel. For low-level attack, 80 30-pound, or 16 100-pound bombs could be carried, while alternately, one 1,100, two 600, or four 300-pound bombs could be dropped from greater heights. Four .30-caliber guns were set low in the nose, one (later two) in the rear cockpit, and one on the floor.
A contract approved on June 30 called for 123 A-20As, and 20 more were added a year later in exchange for the A-17As Douglas resold to Britain. The first A-20A flight was September 6, 1940, and that aircraft was delivered November 30. The fifth A-20A went to the Navy on December 2 as the BD-l, replaced by another A-20A added to the contract. Armor and leak-proof fuel tanks were not provided on the first 17, delivered by January 31, 1941, but were added to 127 remaining A-20As delivered from February 7 to August 29, 1941, and priced at $94,080 each. Fuel capacity was reduced from 500 to 388 gallons by the tank protection.
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