<p>When they fashioned their Model 7B in 1938, designers Jack Northrop and Edward Heinemann of Douglas Aircraft at El Segundo, California, had not even been told that the US Army wanted twin engines, let alone tricycle gear, on an attack aircraft. The contract they won for a prototype was a reluctant one, and the snub-nosed, scoop-bellied machine driven by twin Pratt & Whitney R-1830C engines of 1,100 hp (820 kW) which made its first flight on 26 October 1938 gave little hint of the type's promise, its life being all too brief before a fatal crash on 23 January 1939.
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<p>By January 1940, when the Armé de l'Air began operating the type with its 19th and 32nd Air Groups, initially in Morocco and later in Metropolitan France, the UK was interested in the machine and the US Army had placed an order. For the remainder of its career (even ignoring the fact that the Model 7B prototype and the DB-7B production airplane were totally different machines) there was confusion and overlap between the company term DB-7 and the USAAF designation A-20, and between the popular names Boston and Havoc. Many RAF machines officially had both names, the UK's involvement beginning with a 20 February 1940 contract for 150 aircraft, soon raised to 300 and eventually totalling 781, which became the DB-7B Boston Mk III to distinguish them from the 200 French and 18 Belgian DB-7 Boston Mk Is and 249 French DB-7A Boston Mk IIs diverted to the UK after the fall of France. Many other Boston/Havocs were delivered for RAF use.
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<hi style=hdr1>The Design Process</hi>
<p>Although armament, intended mission and modifications varied widely, the Boston/Havoc twin-engined, shoulder-wing monoplane was fixed in its essential configuration virtually from the beginning. Ever since, it has seemed pleasing and potent to the eye. Pilots transitioning from 'tail-draggers', and so new to tricycle gear, sat high and comfortable and proceeded straight down the taxiway with a commanding view, the cockpit being located forward of the propeller arc for this reason.
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<p>With Heinemann's improvements following the Model 7B prototype came, too, a handicap which would remain with the Boston/Havoc series: because of the narrowness of the fuselage, each crewman was fixed in his own position, unable to exchange places with the other. Injury or death to the pilot would require the nose bombardier and dorsal gunner to bail out. On some machines, for emergencies, token dual controls in the rear gunner's compartment consisted of stick, rudder pedals and throttle, although the gunner had landing problems if an immobilized pilot could not communicate his vision through the intercom.
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<p>The essential design was conventional, with a slender, aluminum-alloy, semi-monocoque fuselage and a single-spar, aluminum-alloy wing with fabric-covered control surfaces. Armament varied, but the basic design called for fixed forward-firing machine guns in various combinations while the rear gunner operated a pivoted 0.303-in (7.7-mm) machine gun in both dorsal and ventral locations, each stocked with 500 rounds of ammunition. Two tandem bomb bays could accommodate a routine load of 1,200 lb (544 kg) of bombs of various types, a typical machine having two vertical racks for six 100-lb (45-kg) bombs. Up to 2,000 lb (907 kg) could be carried over shorter distances.
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<p>With the first aircraft snapped up by France and the UK (including 16 ordered by Belgium), other purchasers came later, including the USAAF with its order for the A-20 Havoc. A few A-20s were sent to the Dutch on Java in 1942, some of these being captured by the Japanese. The USSR received no fewer than 3,125 Boston/Havoc aircraft (as compared with 1,800 for the UK and 1,962 operated by US forces) and these were delivered via transit points as distant as Fairbanks, Alaska and Teheran, Iran. Although it seems doubtful, some American pilots believe they encountered Soviet Lend-Lease Havocs flown by their adversaries in the early days of the Korean War. After 1945, Boston/Havoc airplanes appeared in a number of countries and one of the best-preserved such machines in the world today is located at the Air and Space Museum in Brasilia, restored to postwar Brazilian air force markings.
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<hi style=hdr1>USAAF Havocs</hi>
<p>The USAAF A-20, A-20A and A-20B Havocs saw little action, although numerous A-20Bs ended up in Soviet colors. Some of the earliest Havocs built were converted as P-70 night-fighters. All Segundo and Long Beach production was transferred to Douglas's Santa Monica, California facility in 1941, where the A-20C model emerged, powered by two 1,600-hp (1,193-kW) R-2600-23 engines.
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<p>It was the A-20C which arrived in England in June 1942 with the USAAF's 15th Bomb Squadron, seeing action over the continent and later in North Africa. This and other combat squadrons soon began to acquire the A-20G solid-nose model, which dispensed with a bombardier in favor of nose armament eventually comprising six 0.5-in (12.7-mm) guns. The similar A-20H model had 1,700-hp (1,268-kW) R-2600-29 engines. The A-20E designation covered a handful of aircraft converted from A-20As with R-2600-11 engines, while the single XA-20F was a test aircraft with a 37-mm cannon in the nose. A number of CA-20G transports and TA-20H trainers were produced by conversion.
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<p>In the Pacific, Havocs first saw action when they came under fire in the December 1941 Pearl Harbor attack. A-20As modified by Major 'Pappy' Gunn of the 3rd Bomb Group to carry heavy nose armament were used for low-level strafing in New Guinea. Against the Germans, Havocs ranged across North Africa, then began striking targets in Sicily and on the Italian boot. USAAF Havocs fought on in Normandy, and across Europe to Berlin, although the more advanced Douglas A-26 Invader replaced the Havoc in some squadrons by VE-Day.
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<p>The final major operational variants of the USAAF Havoc were the A-20J and A-20K, which returned to a glazed nose of a new and more streamlined frameless type. Some A-20Ks were painted all-black for night interdiction missions. Representative operators in the European theater of operations included the 47th, 409th, 410th and 416th Bomb Groups; and in the Pacific the 3rd, 312th and 417th Bomb Groups. The last Havoc built (7,385 by Douglas, 140 by Boeing) rolled off the Santa Monica production line on 20 September 1944. Some of these later variants were modified as TA-20J and TA-20K trainers.
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<hi style=hdr1>Flying the Aircraft</hi>
<p>What was it like to fly the Havoc at the height of its operational career? "Sensational!" is the description of one pilot who remembers. Instruments, hydraulics and electrical systems on the Boston/Havoc were regarded as being of a very good quality. Visibility from the pilot's perch in his cockpit was excellent.
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<p>The pilot entered the cockpit by opening a unique, 7-ft (2.13-m) hinged, fold-out hatch and lowering himself into his seat. His cabin floor was foam-carpeted, all pipes and wires were protected behind insulation, and the roomy, armored cockpit provided a 'sports car' feel. On glazed-nose variants, the bombardier sat well forward with a door in the bottom for entry and exit.
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<p>Apart from the remarkable taxiing qualities mentioned earlier, it must be remembered that the Havoc had, in many respects, the feel of a single-seat aircraft and could, indeed, be taken 'upstairs' by the pilot alone. The airplane needed a full take-off roll but, having attained 110 mph (177 km/h), it fairly leaped from the runway. The landing gear retracted very quickly because of the hydraulic accumulator, and the initial rate of climb was impressive. Once aloft, the machine maneuvered with great agility and, apart from its high top speed of around 335 mph (539 km/h), was in every respect a first-rate performer.
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<p>The high, single-rudder tail unit was astonishingly responsive to the pilot's pressure on the pedals, a brief experiment with a twin rudder tail on the 131st DB-7 Boston having been found to offer no improvement. Some pilots found the Havoc a bit too powerful for easy control, at least on letdown and final approach, and felt that the brakes were not effective enough and needed changing too often. It was not a forgiving machine when it came to ending a fast landing in a full stop on a short runway.
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<hi style=hdr1>Reconnaissance and Night-Fighting</hi>
<p>British success with this aircraft type as a night-fighter may have inspired the USMF's decision to convert early A-20 Havocs to the P-70 night-fighter standard. Seizing the opportunity offered by the availability of British air intercept radar, the first A-20 (39-735) was modified to XP-70 standard in 1942. A further 59 A-20 aircraft were converted to P-70s, while 13 A-20Cs received the P-70A-1 nomenclature and 26 A-20Gs were designated P-70A-2. Further conversions were the sole P-70B-1 and a small number of P-70B-2s.
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<p>Throughout the P-70 program various attempts were made to refine and develop the night-fighting capability of the aircraft but, while these were going on, Northrop (the firm which designer John Northrop had restarted in 1938) was designing its own twin-engined night-fighter from the ground up, and in the end the P-61 Black Widow offered considerable performance advantages over the P-70. The P-70 was used primarily for training, although a few saw combat in the Pacific.
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<p>The 'foto' reconnaissance designation F-3 was applied to camera-carrying Havocs after a proposal for an 'observation' derivative, the O-53, was cancelled. A single A-20 (39-741) was revamped to become the XF-3, carrying cameras in the fuselage bay, while two further machines became YF-3s with various optical and camera installations. The potential of the Havoc as an intelligence-gathering platform, especially because of its good performance at low altitude, was obvious. Once 'bugs' were worked out of the photo-reconnaissance configuration, 46 A-20J and A-20K aircraft were modified to become F-3As. The relatively small number of F-3A reconnaissance craft actually saw a disproportionate employment in battle, and one F-3A Havoc was the first Allied aircraft to touch down at Itazuke air base in Japan following the 15 August 1945 surrender.
<item><hi format=bold>Performance:</hi> maximum speed 339 mph (546 km/h) at 12,400 ft (3,780 m); cruising speed 255 mph (410 km/h); initial climb rate 2,910 ft (887 m) per minute; service ceiling 25,800 ft (7,865 m); range 1,090 miles (1,754 km) with normal bomb load
<item><hi format=bold>Weights:</hi> empty 16,100 Ib (7,303 kg); maximum take-off 27,200 lb (12,338 kg)
<item><hi format=bold>Dimensions:</hi> span 61 ft 4 in (18.69 m); length 48 ft 0 in (14.63 m); height 17 ft 7 in (5.36 m); wing area 464.0 sq ft (43.11 m<su>2</su>)
<item><hi format=bold>Armament:</hi> six fixed forward-firing 0.5-in (12.7-mm) machine guns in the nose, two 0.5-in (12.7-mm) machine guns in the power-operated dorsal turret and one manually-operated 0.5-in (12.7-mm) machine gun in the ventral position, plus up to 4,000 lb (1,814 kg) of bombs
