|A-20 Havoc |
|A-20G of the United States Army Air Forces|
|National origin||United States|
|Manufacturer||Douglas Aircraft Company|
|First flight||23 January 1939|
|Introduction||10 January 1941|
|Primary users||United States Army Air Forces|
Soviet Air Force
Royal Air Force
French Air Force
|Developed into||Douglas DC-5|
Designed to meet an Army Air Corps requirement for a bomber, it was ordered by France for their air force before the USAAC decided it would also meet their requirements. French DB-7s were the first to see combat; after the fall of France the bomber, under the service name Boston continued with the Royal Air Force. From 1941, night fighter and intruder versions were given the service name Havoc. In 1942 USAAF A-20s saw combat in North Africa.
It served with several Allied air forces, principally the United States Army Air Forces (USAAF), the Soviet Air Forces (VVS), Soviet Naval Aviation (AVMF), and the Royal Air Force (RAF) of the United Kingdom. A total of 7,478 aircraft were built, of which more than a third served with Soviet units. It was also used by the air forces of Australia, South Africa, France, and the Netherlands during the war, and by Brazil afterwards.
In most British Commonwealth air forces, the bomber variants were known as Boston, while the night fighter and intruder variants were named Havoc. The exception was the Royal Australian Air Force, which used the name Boston for all variants. The USAAF used the P-70 designation to refer to the night fighter variants.
In March 1936, a design team headed by Donald Douglas, Jack Northrop, and Ed Heinemann produced a proposal for a bomber-reconnaissance aircraft powered by a pair of 450 hp (340 kW) Pratt & Whitney R-985 Wasp Junior 9-cylinder radial engines mounted on a shoulder wing. It was estimated to be capable of 250 mph (400 km/h) with a 680 lb (310 kg) bomb load. Reports of aircraft performance from the Spanish Civil War indicated that this design would be seriously underpowered, and it was canceled.
In 1937, the United States Army Air Corps (USAAC) issued a new specification for an attack aircraft. To meet this requirement, the Douglas team, now headed by Heinemann, developed the Model 7B, with a similar layout to the 7A, but was powered by 1,100 hp (820 kW) Pratt & Whitney R-1830-S3C3-G Twin Wasp 14-cylinder engines, and carried a bombload of up to 2,000 lb (910 kg). It faced competition from the North American NA-40, Stearman X-100, Martin 167F, and an unbuilt design from Bell Aircraft, the Model 9. The Air Corps invited all five companies to build prototypes at their own expense and to submit sealed bids for production of their aircraft.
The prototype Model 7B made its first flight on 26 October 1938. The model attracted the attention of a French Purchasing Commission visiting the United States. The French discreetly participated in the flight trials, so as not to attract criticism from American isolationists. The Model 7B crashed on 23 January 1939 while demonstrating single-engine performance, killing the test pilot and seriously injuring a French observer aboard the aircraft. The presence of a foreigner on a test flight for an aircraft still under development caused a scandal in the press. Despite the crash, the French were impressed enough to place an order for 100 production aircraft on 15 February 1939, following this up with an order for 170 more in October 1939.
As a result of the French order, Heinemann carried out another major redesign of the aircraft. While the design's wings were largely unchanged, the revised design had a new deeper but narrower fuselage, which accommodated a crew of three - a pilot, bombardier and a gunner. The wing was mounted lower than on the Model 7B, while the engines, 1,000 hp (750 kW) R-1830-SC3-Gs, were mounted in nacelles slung under the wings. Normal bombload was 1,410 lb (640 kg), or 1,800 lb (800 kg) in overload conditions, with a defensive armament of single 7.5mm MAC 1934 machine guns in dorsal and ventral mounts and four fixed forward-firing guns in the nose. The revised aircraft, the DB-7, first flew on 17 August 1939.
In 1939, the USAAC decided that the new bomber was best placed to meet its requirements for an attack bomber, which had been updated in 1938 from those that gave rise to the Model 7B, and in June 1939, it ordered 186 aircraft powered by Wright R-2600 Twin Cyclone engines, under the designations A-20 and A-20A (with the A-20s having 1,700 hp (1,300 kW) turbosupercharged R-2600-7 engines and the A-20As having 1,600 hp (1,200 kW) supercharged R-2600-3 or -11 engines. These had a larger vertical tail to cope with the increased power of the Wright engines, had a longer nose to give more room for the bombardier/navigator, and carried more fuel. R-2600 powered aircraft also proved popular for export, with France ordering 100 DB-7As powered by the R-2600 but with the short nose of the DB-7 in October 1939, and 480 long-nosed DB-73s, equivalent to the A-20A, in April 1940 and Britain ordering 300 DB-7Bs, again equivalent to the A-20A in February and April 1940.
In a report to the British Aeroplane and Armament Experimental Establishment (AAEE) at RAF Boscombe Down, test pilots summed it up as: "has no vices and is very easy to take off and land ... The aeroplane represents a definite advantage in the design of flying controls ... extremely pleasant to fly and manoeuvre." Ex-pilots often consider it their favorite aircraft of the war due to the ability to toss it around like a fighter. The Douglas bomber/night fighter was found to be extremely adaptable and found a role in every combat theater of the war, and excelled as a true "pilot's aeroplane".
When DB-7 series production finally ended on 20 September 1944, a total of 7,098 had been built by Douglas and a further 380 by Boeing. Douglas redesigned its Santa Monica plant to create a mechanized production line to produce A-20 Havocs. The assembly line was over a mile long (6,100 feet), but by looping back and forth, fitted into a building that was only 700 feet long. Man-hours were reduced by 50% for some operations while production tripled.
The French order called for substantial modifications to meet French standards, resulting in the DB-7 ( Douglas Bomber 7) variant. It had a narrower, deeper fuselage, 1,000 hp (750 kW) Pratt & Whitney R-1830-SC3-G radials, French-built guns, and metric instruments. Midway through the delivery phase, engines were switched to 1,100 hp (820 kW) Pratt & Whitney R-1830-S3C4-G. The French designation was DB-7 B-3 (the B-3 signifying "three-seat bomber").
DB-7s began to be delivered from Douglas's El Segundo, California production line on 31 October 1939, and the passing of the "Cash and Carry" act on 4 November 1939 allowed the aircraft to be handed over in the United States to the French, who would then be responsible for delivering the aircraft. The DB-7s were shipped to Casablanca in French North Africa where they were reassembled and tested before being handed over to operational units of the Armée de l'Air. When the Germans attacked France and the Low Countries on 10 May 1940, about 70 DB-7s had reached North Africa, equipping three Escadrilles (squadrons), which were transferred from Africa to the French mainland in response to the German attack. They flew about 70 sorties against the advancing Germans during the Battle of France, with at least eight aircraft being lost, but before the armistice surviving aircraft were evacuated to North Africa to avoid capture. Here, they came under the control of the Vichy government and briefly engaged the Allies during Operation Torch, the Allied invasion of French North Africa in November 1942.
After French forces in North Africa had joined the Allies, DB-7s were used as trainers and were replaced in front line escadrilles with Martin B-26 Marauders. Free French squadron I/120 Lorraine, under RAF control, was based in England and re-equipped in 1943 with Boston IIIAs, later with Boston IVs. It was part of No. 2 Group RAF and then the Second Tactical Air Force and carried out numerous raids against targets in mainland Europe.
After the fall of France, there were still a substantial number of DB-7s which had not yet been delivered to the Armée de l'Air. The remainder of the order which was to have been delivered to France was instead taken up by the UK via the British Purchasing Commission. In the course of the war, 24 squadrons operated the Boston in Britain, the Mediterranean and North Africa.
The French had originally intended to use the DB-7 as a short-range tactical attack aircraft, but its range was too short for the RAF to be able to use them as light bombers against German targets in Europe. The RAF was in desperate need of any aircraft suitable for night fighting and intruder duties. The type saw its first operations with the RAF in early 1941, when 181 Boston Mk IIs began to be flown as night fighters and intruders. There were two basic versions of the Havoc I, an Intruder version (glazed nose, five 0.30-inch machine guns and 2,400 pounds of bombs) and a Night Fighter version (AI Mk.IV radar and eight 0.30-inch machine guns).
Some Havocs were converted to Turbinlite aircraft which replaced the nose position with a powerful searchlight. The Turbinlite aircraft would be brought onto a hostile aircraft by ground radar control. The onboard radar operator would then direct the pilot until he could illuminate the enemy. At that point a Hawker Hurricane fighter accompanying the Turbinlite aircraft would make the attack. The Turbinlite squadrons were disbanded in early 1943.
All the French DB-7As, an improved DB-7 version, were delivered to the RAF, where they were given the name Havoc II and converted to night fighters. Eventually the British Purchasing Commission ordered a British version as the DB-7B and the RAF named it Boston III. The Boston III was the first to operate with the RAF as a light bomber. They were supplied to squadrons in the United Kingdom and Middle East (later moved to bases in Italy) replacing Bristol Blenheims. Their first raid took place in February 1942. Many Boston IIIs were modified to Turbinlite or Intruder planes.
Through Lend-Lease, Soviet forces received more than two-thirds of the A-20B variant manufactured and a significant portion of G and H variants. The A-20 was the most numerous foreign aircraft in the Soviet bomber inventory. The Soviet Air Force had more A-20s than the USAAF.
They were delivered via the ALSIB (Alaska-Siberia) air ferry route. The aircraft had its baptism of fire at the end of June 1942. The Soviets were dissatisfied with the four .30-calibre Browning machine guns, capable of 600 rounds per gun per minute, and replaced them with the faster-firing, 7.62 mm (0.300 in) calibre ShKAS, capable of up to 1,800 rounds per gun per minute. During the summer of 1942, the Bostons flew ultra-low-level raids against German convoys heavily protected by flak. Attacks were made from altitudes as low as 33 ft (10 m) and the air regiments suffered heavy losses.
By mid-1943 Soviet pilots were familiar with the A-20B and A-20C. The general opinion was that the aircraft was overpowered and therefore fast and agile. It could make steep turns of up to 65° of bank angle, while the tricycle landing gear made for easier take-offs and landings. The type could be flown even by crews with minimal training. The engines were reliable but sensitive to low temperatures, so the Soviet engineers developed special covers for keeping propeller hubs from freezing up.
Some of these aircraft were armed with fixed-forward cannons and found some success in the ground attack role.
By the end of the war, 3,414 A-20s had been delivered to the USSR, 2,771 of which were used by the Soviet Air Force.
In October 1941 the Netherlands government in exile ordered 48 DB-7C planes for use in the Dutch East Indies. Delivery had been scheduled for May 1942 but because of the desperate situation US government agreed to divert 32 DB-7B Boston III aircraft to the Dutch East Indies in advance.
The first six were delivered by ship in February 1942. Only one aircraft was assembled in time to take part in the action. The Japanese captured the remaining aircraft of the delivery, and at least one was repaired and later tested by the Imperial Japanese Army.
The next 22 DB-7Bs to be delivered to the East Indies were diverted to the Royal Australian Air Force. They served with No. 22 Squadron RAAF and fought in the East Indies from September 1942. RAAF Bostons took part in the Battle of the Bismarck Sea and in attacks on a large Japanese convoy headed toward Lae.
Some A-20A/C/G planes arrived from the US from September 1943. By November 1944, No 22 Squadron was going to be assigned to the Philippines. Thirteen Bostons were destroyed on the ground during a Japanese raid on Morotai. The squadron was withdrawn to Noemfoor, where it was re-equipped with Bristol Beaufighters before it returned to action. Surviving Bostons were relegated to transport, mail delivery and communications.
In 1940, the US military's indifference to the type was overcome by improvements made for the French and British Commonwealth air forces.
The USAAC was impressed enough by the A-20A's high power to weight ratio and easy handling characteristics. Two variants were ordered, in a tranche of more than 200 aircraft: the A-20 for high-altitude daylight bombing and the A-20A for low- and medium-altitude missions. It was intended that the high-altitude variant would be fitted with turbosupercharged Wright R-2600-7 engines; after a prototype suffered technical problems, the USAAC changed its order and an initial shipment of 123 A-20As (with less-powerful R-2600-3 engines) and 20 A-20s (R-2600-11) entered service in early 1941. A further 59 aircraft from this first order were received as P-70 night fighters, with two-stage supercharged R-2600-11 engines.
The A-20B, another high-altitude bomber variant – lacking heavy armor and self-sealing fuel tanks – received a significant order from the USAAC: 999 aircraft (although two-thirds of these were exported to the USSR). With the lessons of the Pacific in mind USAAF ordered A-20G in June 1942.
A major shipment of DB-73s originally destined for France was retained by the US government and converted to A-20C/G attack configuration. The USAAF received 356, most of which were operated by the 5th Air Force in the South West Pacific theater. When the war started 27th Bombardment Group (minus its A-20As) was in the process of being sent to the Philippines where it was to have been re-established as an A-20 unit, but the first operational unit in actual combat was the 89th Bombardment Squadron which began operations in New Guinea on August 31, 1942.
In early 1944, 312th and 417th Bombardment Groups were sent to New Guinea, equipped with A-20Gs. Most sorties were flown at low altitudes, as Japanese flak was not as deadly as German flak, and it was soon found that there was little need for a bomb aimer. Consequently, the bomb aimer was replaced by additional machine guns mounted in a faired-over nose. A-20Gs were an ideal weapon for pinpoint strikes against aircraft, hangars, and supply dumps. When operating in formation their heavy forward firepower could overwhelm shipboard antiaircraft defenses and at wave-top level (resembling a torpedo run) they could skip their bombs into the sides of transports and destroyers with deadly effect. In addition, the captains of small Japanese escorts (destroyers, for example) assumed the approaching aircraft were making torpedo runs and turned their vessels bow-on to the aircraft in defense, making the strafing far more devastating to the unarmored escorts and often leaving them even more vulnerable to follow-up "skip-bombing" runs.
After the New Guinea campaign, the A-20s squadrons moved to the Philippines. In 1944, three full four-squadron A-20 groups were active in the campaign that led to the invasion of Luzon. After the Philippines were secured, A-20s attacked Japanese targets in Formosa.
The first night-fighter squadron to use P-70s in combat was based at Henderson Field to intercept high-flying Japanese night raiders. The 418th and 421st Night Fighter Squadrons briefly flew P-70s in New Guinea. The P-70s scored only two kills during the Pacific war as its performance was not good enough to intercept Japanese night raiders, and were replaced by Northrop P-61 Black Widows as soon as possible.
In Europe, USAAF A-20 crews flew their first combat missions attached to RAF units. On 4 July 1942, 12 crews from the 15th Bombardment Squadron became the first members of the 8th Air Force to enter combat. They flew Bostons belonging to No. 226 Squadron RAF from bases in England on missions against enemy airfields in the Netherlands.
USAAF A-20s were assigned to North Africa and flew their first combat mission from Youks-les-Bains, Algeria, in December 1942. They provided valuable tactical support to allied ground troops, especially during and following the Battle of Kasserine Pass. During the North African campaign, many of the A-20s were fitted with additional forward-firing machine guns. Following the German surrender in Tunisia, the A-20s moved to bases in Italy, Corsica, France, and then back to Italy in January 1945.
Four P-70 night fighter squadrons were sent to North Africa in 1943. When they arrived they operated Bristol Beaufighter night fighters. Later the 427th Night Fighter Squadron was deployed to Italy, but the squadron exchanged its P-70s for Northrop P-61 Black Widows and so no night fighter squadron used their P-70s in combat in Europe.
Meanwhile, in England, three A-20 equipped Bombardment Groups were assigned to the 9th Air Force and became operational in 1944. They started using the same low-level tactics that had been so successful in the Pacific, but due to heavy German flak, losses were too high and the tactics were changed to medium-level raids. After supporting advancing Allied forces into France until the end of 1944, all units switched to the Douglas A-26 Invader. Reconnaissance Havocs joined the 9th Air Force in 1944. Its 155th Photographic Squadron (Night) was issued F-3As for night photographic operations.
Three A-20s are in flying condition as of 2022. All are G-variants and registered in the US.
The last of the 7,478 A-20s built (a K-variant) was completed in September 1944. The type was replaced in some air forces before the war's end, by types including the Douglas A-26 (USAAF), Bristol Beaufighter (RAAF), and de Havilland Mosquito (RAF). Perhaps the last substantial user was the Força Aérea Brasileira, which did not retire the A-20 until the late 1950s.
The number of airframes declined rapidly. By the early 1960s, only six complete A-20s existed, worldwide. That number has since grown slowly, with the discovery of crash sites in the Pacific and Eastern Europe.
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