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Updated on November 26, 2021
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The Douglas DB-7/A-20 Havoc/Boston was the most produced attack bomber during World War II. A total of 7,478 were built, most at Douglas, although 380 were built at the Boeing plant in Seattle.
Main versions
Model 7B
The first sketch of the plane was drawn in 1936 as Model 7A, but it was abandoned because it was clear that the output of its engines, 450 hp each, was unsufficient. In 1937, The United States Army Air Corps (USAAC) issued a new specification for an attack aircraft; the Douglas team developed the model 7B, powered by two 1100 hp Pratt & Whitney R-1830-S3C3-G Twin Wasp engines, able to carry a bombload of 910 kg. The prototype, Manufacturer Serial Number: 379, flew on 26 October 1938, and captured the interest of the French AF. The prototype could easily be converted into two alternative configurations:
In this latter configuration, the prototype crashed on 23 January 1939 during a test of one engine flight, killing the pilot and injurying a member of the French commission that was inside the plane. The presence of a foreigner in the crashed plane caused scandal between the U.S. insulationists. Despite the crash of the prototype, French were well impressioned and placed an order of 100 planes in February 1939, followed by a further order of 170 in October.
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Images from Squadron/Signal n. 144 'A-20 Havoc in action' of Jim Mesko |
DB-7 prototype Thanks to the French orders, the Douglas made a deep revision of the project, leading to the production DB-7 (factory official designation), or DB-7B3 (French designation, where B3 is for three-men bomber).MSN: 431-530, French serial: 1-100 It had a fully reprojected fuselage, deeper but narrower, with a crew of three: pilot, navigator/bomber, rear gunner/radio operator. The wingswere positioned in mid position instead than at the shoulder, and the gondolas with 1,000 hp R-1830-SC3-Gs engineswere moved under the wings to avoid too long landing gear legs. The bomb load was of 640 kg (800 in overload) and was armed with 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 reprojected aircraft first flew on 17 August 1939.
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DB-7/Havoc I
DB-7s were produced with R-1830-S3C3-G engines with 1100 hp (the first 100 aircraft), DB-7s with R-1830-S3C4-G engines with 1200 hp (the next 170). The nacelle was shorter and more rounded than following types. The rear upper armament consisted of twin 7.62 mm machine guns, while further 7.62 machine guns were fixed on the nose sides. A bomb load of 640 kg (800 in overload) was installed in vertical position. Double command were installed in the gunner's cockpit, although this was unuseful because he lacked of visibility forward. Of the 270 DB-7s ordered, 116 were accepted by the French before the armistice. - DB-7, Boston I, Boston II, Havoc I: (Two-speed engine) MSN: 2288-2382, French serial: 101-(270), 92 delivered to France, the first 30 were built with the single-speed engine - DB-7, Boston II, Havoc I: (Two-speed engine) MSN: 2383-2457, ordered by France, delivered to England |
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Remaining planes were delivered to the RAF; they lacked the range required by the RAF to use them as bombers, so they were adapted as night intruders and night fighters and named Havoc I. Some Havoc I, aside Havoc II were adapted as 'Turbinlite' with a huge searchlight in the flat nose.
A total of 130 DB-7s are listed on RAF rolls as Boston I, with RAF serials being AE457 to AE472, AX848 to AX851, AX910 to AX918, AX920 to AX975, BB890 to BB912, BD110 to BD127, and DK274 to DK277 The ex-French contract DB-7s powered by the more-powerful 1100 hp R-1830-S3C4-G engines (first introduced on the 131st DB-7) equipped with two-speed superchargers were temporarily designated Boston II. RAF serials were AW392 to AW414, BJ458 to BJ501, BK882, BK883, BL227, BL228, BT460 to BT465, BV203, DG554, and DG555. The first Boston II to Havoc I conversion was carried out by the Burtonwood Aircraft Repair Depot, Liverpool, during the winter of 1940/41. More than a hundred of these conversions were completed during the next few months. In all, 181 Boston aircraft were converted to Havoc I configuration. Included in this total were some Boston I aircraft which had been reengined. Serials were AW392 to AW414, AX848, AX851, AX910 to AX918, AX921, AX923, AX924, AX930, AX936, AX974, AX975, some from AE457/AE472, BB891 to BB895, BB896 to BB904, BB907 to BB909, BB91, BB912, BD110 to BD127, BJ458 to BJ501, BK882, BK883, BL227, BL228, BT460 to BT465, BV203, DG554, DG555. Number 92 Squadron received twenty modified Havoc I (Pandora) intruder aircraft, the name "Pandora" being a code name for the Long Aerial Mine (LAM) which was an explosive charge towed by a 2000-foot length of cable stowed in the bomb bay of the Havoc. The LAM was trailed in the path of enemy aircraft in the hope of scoring a hit. Serials of Boston aircraft known to have been equipped with this device include AX913, BK883, BT465, and DG554. This device was not very successful, and only one victory was attributed to this system. No 92 Squadron was disbanded in November of 1941, and the "Pandora" Havocs were converted back to Intruder configurations. Serials of Havoc aircraft known to have been equipped with the Turbinlite included AX913, AX924, AX930, BB897, BB899, BB907/BB909, BD100, BD111, BD120, AW392, AW393, AW400, AW401, AW404, AW406, AW411, AW412, BJ460, BJ461, BJ467, BJ469, BJ470, and BK882. The following serials were transferred to the USAAF: AX913, AX922, BB891, BB896, AW394, AW400, AW403, BJ461, BJ466, BJ473, BJ488, BJ499, and BT464.
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Image from https://ww2aircraft.net/forum/media/douglas-havoc-i-nightfighter.14452/ |
DB-7A/Havoc II
None of these were delivered before the fall of France and they were sent to the UK instead. These were named Havoc II and converted into night fighters, by the addition of 12.7 mm machine guns in their noses and extra fuel tanks. They had a top speed of 550 km/h at higher altitudes. A total of 39 aircraft (including some Havoc I) were briefly used as Turbinlites, with a radar and a powerful research light on their nose.
- DB-7A, DB-71, Havoc II, Boston III: MSN: 2951-3049. As it turned out, the DB-7A was basically the export version of the USAAC A-20A. Due to the use of more powerful engines, the nacelles were elongated and the rear portion of the nacelles had a longer and more pointed shape as compared to the nacelle of the DB-7. All of the DB-7As were delivered to the Royal Air Force, where they were given the name Havoc II and assigned the serials AH430 to AH529. Thirty-nine Havoc IIs (among them serial numbers AH431, AH432, AH434, AH436, AH444 to AH447, AH450, AH451, AH453, AH460, AH468, AH470, AH472, AH473, AH478, AH479, AH481, AH483, AH484, AH491, AH497, and AH503) were later modified to carry 2700 million candlepower Turbinlite searchlights in their noses. The few DB-7As not converted to Havoc II configuration were designated Boston III, and were not distinguished from DB-7Bs, DB-73s and ex-USAAF A-20Cs which were also designated Boston III. AH438, AH451, and AH454 were transferred to the USAAF. |
Image: Imperial War Museum
Image: wikimedia commons |
DB-7B/Boston III
32 planes built for England were assigned to this order, but only 4 were delivered and then destroyed by Dutch themselves, 2 were captured by Japaneses, 22 were delivered to Australia, 4 remained in USA, of which 3 were later delivered to Soviet Union.
- DB-7B, Boston III: MSN: 3300-3449, RAF serials were W8252 to W8401, MSN: 3450-3599, RAF: Z2155 to Z2304, MSN: 3840-4079, RAF: AL668-907. Serials of the DB-7Bs converted to Intruder configuration include W8256, W8262, W8264, W8266, W8268, W8278, W8281, W8283, W8284, W8290, W8292, Z2155, and Z2165. Boston III aircraft fitted with Turbinlites included W8257, W8265, W8275, W8276, and W8300. W8274, W8277, W8316, W8328, W8341, W8352, W8366, W8369, W8393, W8396, Z2184, Z2214, and Z2270 were converted to Havoc N.F.II. W8401 and Z2189 converted to trainers. Z2200 was transferred to the USAAF.
- DB-73, (DB-7C), Boston IIIA: built as DB-7B, MSN: Boeing 2130-2203, 2718-2883; RAF: AL263-502. Most of the RAF DB-7B aircraft never did reach Britain. Large numbers were diverted to the Soviet Union following the German attack on June 22, 1941, with some 151 of the order ending up going to the Russians. Following the American entry into the war, substantial numbers of Bostons destined for the RAF were requisitioned by the USAAF. Some 162 Douglas-built and 194 Boeing-built Bostons ended up being seized by the USAAF in this manner. It was not until late 1942 that the deliveries of Bostons to Britain were resumed. By this time, the deliveries to Britain were being carried out under the terms of Lend-Lease rather than as direct purchases. The aircraft designated for delivery to Britain were given USAAF designations of A-20C and were assigned USAAF serial numbers. They were known as Boston IIIA in RAF service. They were basically similar to the USAAF A-20C, with the exception of the use of British equipment and armament. RAF serials were BZ196/BZ352, BZ355/BZ378, and BZ381/BZ399. Other Boston IIIAs were taken over in the field by the RAF, some of them retaining their original USAAF serial numbers, while others received new RAF serials (HK869, HK870, HK872/HK879, HK912, HK918, HK923, HK924, HK934, HK960, HK962, HK964, HK967, HK969, HK970, HK972, and HK973). 22 Boston III and IIIAs were diverted to the Royal Australian Air Force (RAAF). |
Image from World War Photos
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A-20 U:S. version for high-altitude bombing, similar to the DB-7B. The A-20 was to be fitted with turbosupercharged Wright R-2600-7 engines, but these were bulky and the prototype suffered cooling problems, so the remainder were completed with the two-stage supercharged R-2600-11. 59 of them were converted into P-70 night fighters and 3 into F-3 reconnaissance aircraft.
Douglas A-20: MSN: 2874-2936 39-735 Douglas A-20 Havoc -modified as XP-70 night fighter. 39-736/740 Douglas P-70 Havoc 39-741 Douglas XF-3 Havoc - transferred to US Navy as BD-1 BuNo 4251 39-742/744 Douglas P-70 Havoc 39-745 Douglas YF-3 Havoc 39-746/747 Douglas P-70 Havoc 39-748 Douglas YF-3 Havoc 39-749/797 Douglas P-70 Havoc - Douglas A-20A: MSN: 2751- 2873 39-721/734 Douglas A-20A Havoc 40-071/179 Douglas A-20A Havoc 077, 085, 118, 139, 143, 144, 162 to RAAF 40-3143/3162 Douglas A-20A Havoc 3159, 3160 to RAAF |
Image from Squadron/Signal n. 144 'A-20 Havoc in action' of Jim Mesko
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A-20A/Boston III U.S.version for low and medium altitude combat, similar to the DB-7B, or to A-20 without supercharger. The U.S. Army ordered 123 A-20As with R-2600-3 engines, and 20 more with the more powerful R-2600-11. They entered service in the spring 1941. At first thew wore a Natural metal finish, then started to be painted with the Olive Drab/Neutral grey livery. At first they had cooling vents on the sides of the engine cowlings, but this characteristic was soon abandoned.
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Image from Squadron/Signal n. 144 'A-20 Havoc in action' of Jim Mesko
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| The USAAF used the British name Havoc for the A-20A, while the RAAF referred them, again, as Boston III. |
Image from World War Photos |
A-20B It was a lighter and faster version that resembled the DB-7A rather than the DB-7B, with light armor and stepped rather than slanted nose glazing. It was moved by two R-2600-11engines, and featured a nose with glazing similar to DB-7A and an upgraded rear bomb bay with horizontal bombs layout that increased the accuracy of bombing. It was also possible to carry an auxiliary tank for ferry flights in the bombs bay. There were only two machine guns in the nose, the powerful Browning 12.7 mm; the same type of weapon was mounted in the dorsal position of the gunner, while the machine gun in the lower hatch was still of 7.62 mm as in earlier versions. They also retained the rear-facing 7.62 mm machine guns in the gondolas introduced on the DB-7B and A-20A, but these weapons were rarely installed on A-20B. Starting from late 1940, A-20B were produced by two companies: in Santa Monica they made A-20B-DO, and in Long Beach-A-20B-DL, which had slight differences in configuration. At the front, they were received by one group in Morocco and one reconnaissance squadron in England, but they were considered too vulnerable in combat because of the lack of self-sealing tanks and the poor armour protection. Of 999 A-20B built, 665 were exported to the Soviet Union, so only 334 served with the USAAF, often in training unit. 8 A-20B were received by the US Navy as BD-2 and used as target tow. Right: photo of an A-20B in Soviet service.
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- Douglas A-20B Havoc 41-2671/3669 Douglas A-20B Havoc MSN 5001/5999 Manufacturer Serial Number: In some respects, the A-20B was inferior to the A-20A which preceded it, since it was based on the DB-7A airframe rather than the DB-7B and hence lacked self-sealing fuel tanks and was not as well-armored. In the field, many A-20Bs had their Plexiglas nose areas faired over and the bombardier position replaced by a battery of four to six forward-firing 0.50-inch machine guns. In spite of its large production run, the A-20B did not see extensive service with the USAAC, since most of them (some 665 aircraft) were exported to the Soviet Union under Lend-Lease. Eight A-20Bs (serial numbers 41-2771 to 41-2778) were leased to the US Navy as high speed target tugs under the designation BD-2. BuNos were 7035/7042.
Eight A-20B went to the Navy as fast target tow planes and named DB-2. They were operated by the USMC.
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Image from Squadron/Signal n. 144 'A-20 Havoc in action' of Jim Mesko |
Few A-20B had a solid nose with 12.7 mm machine guns fitted in it.
A-20B-DL:
A-20B-DL: 625 AIRPLANES ASSIGNED TO THE SOVIET UNION |
Image from World War Photos |
A-20C/Boston III/Boston IIIA It was an attempt to develop a standard, international version of the DB-7/A-20/Boston, produced from early 1941. It reverted to the slanting nose glass of DB-7C/A-20/A-20A/Boston III, and it had RF-2600-23 engines, self-sealing fuel tanks, and additional protective armor. All the weapons were of 7.62 mm caliber; the blisters with 4 machine guns on the nose sides were resumed; the dorsal position had twin 7.62 mm machine guns. The uneffective rearwards-firing machine guns in the engine nacelles were definitively deleted. An optional conformal external tank for long ferries could be mounted under the fuselage. The A-20C was also built by two different factories: Douglas plant in Santa Monica (A-20C-DO, produced 808 ones) and the Boeing plant in Seattle (A-20C-VO, made 140 ones). Planes from Santa Monica had a visual difference in the configuration of the exhaust pipes, when compared to the Boston III: they were not collected into one collector on the nacelle outer sides, but appeared as a row of pipes covered by a lateral flap, or, in later production A-20C, as individual exhaust stacks around the engine cowlings just as on A-20G. Planes from Seattle were distinguishable by the fact that the exhaust pipes were not sideways, but downwards, and for the installation of anti-dust "tropical" filters that were installed in two ways: in an extension forward of the standard carburetor air intake, or inside the nacelle, forming a characteristic"hump"on it. A total of 948 A-20C were built for Britain, but many were diverted
to Soviet Union or retained by the USAAF after the Japanese attack on
Pearl Harbor, that used them mainly for training.
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Image from World War Photos
Image from World War Photos
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A-20 D/E F These designation were given to versions that remained at the prototype stage or were built in very few samples. A-20D was a turbocharged and lightened version of the A-20B, probably never built because of the difficulties both with superchargers and the excessive vulnerability of A-20B. A-20E were some lightened A-20A airframes, utilized for training and tests. A-20F was an A-20A equipped with General Electric remote control turrets in upper and lower position, and a 37 mm gun fixed in the nose, with a big protruding barrel. At least two modified planes were built. Right: the nose of an A-20F. The 37 mm gun barrel and the dorsal and ventral turrets are recognizable.
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Image from Squadron/Signal n. 144 'A-20 Havoc in action' of Jim Mesko |
A-20G The A-20G was an assault version with solid nose and increased protection. In G-1 up to G-4 series, the nose was armed with 4 20 mm Hispano guns with 60 rounds each, whose barrels strongly protruded, and two M2 Browning machine guns. It had no longer bumps for machine guns protruding on the nose sides, typical of some earlier versions as the Boston III. The bomb bay was lenghtened rearwards and the bomb load raised up to 1.800 kg in overload. New optional wing pylons were introduced, stiffened by oblique struts.The empty weight increased of about a ton. The exhaust pipes were now individual, coming out through openings of the engine cowlings; they had a MN-26Y radio compass ring aerial on the back. The defensive armament was, in versions G-10 to G-19, made by one 12.7 M2 Browning machine gun in dorsal position and one 7.7 mm in ventral position firing through an openable hatch, both positions were similar to earlier versions apart for the weapons. Nearly all the A-20G with 20 mm guns were delivered to Soviet Union. Starting from G-5, the poorly accurate nose guns were replaced by 12.7 mm machine guns (6 in total). The production of series G-1 to G-19 totalized 750 planes.
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Above: nearly all A-20 G-1 with protruding 20 mm guns delivered to the Soviet Union in 1943. Image from 'Bostony v Sovetskom Soyuze' of Vladimir Kotelnikov, Yandex
Above: :starting with G-5, the 20 mm guns in the nose were replaced by 12.7 mm machine guns. Image from World War Photos
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On the G-20, a power-driven Martin 250GE turret fitted with two 12.7 mm machine guns was fitted, with the fuselage15 cm wider in its upper part around the turret, and the ventral tunnel gun changed from a 7.7 mm to another 12.7 mm Browning. The engines were two 1,600 hp R-2600-23. The A-20G was delivered from February 1943 and was the most produced version, with 2850 built. US A-20Gs were used on low-level sorties in the New Guinea theatre. Soviet Union received more than 2.000 A-20G, becoming its major customer. |
Above: starting with A-20G-20, a turret with two 12.7 mm was fitted in an enlargement of the top fuselage. Image from World War Photos
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A-20H
30 A-20H were delivered to the Soviet Union.
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Image from World War Photos
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A-20J/Boston IV
The A-20J differed from late A-20G because it carried an additional bombardier cockpit in an extended acrylic glass nose section that increased the total lenghth of the plane. It was equipped with the most advancedequipment at that time, including an excellent Norden M-15 bomb sight, and it was intended to lead bomber formations, with the following standard A-20Gs dropping their bombs when signaled by the leader. They were also used independently, either as scouts or for missions that required very precise bombing A total of 450 were built from the summer of 1944; 169 were delivered to the RAF which designated them Boston Mk IV. 48 A-20J were delivered to the Soviet Union in 1944. |
Above: Boston IV of RAF with ventral ferry tank. Image from Squadron/Signal n. 144 'A-20 Havoc in action' of Jim Mesko
Above: French A-20J with the invasion stripes used during the invasion of Normandy in 1944. |
A-20K/Boston V
110 between A-20K were delivered to the Soviet Union starting from 1944.
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Above: A-20K with overall black livery and darkened national insignias. The camouflaged rudder is from another plane. Image from World War Photos |
7,385 DB-7s, Havocs and Bostons were built during the war. Most of them were for the Soviet forces that received 3128 of them, 3077 from U.S and 77 from U.K. Just to make a comparison, the U.S. utilized 1,644 and the R.A.F. 1,489. The production of A-20 ended in September 1944 in favour of its successor, the A-26 Invader. The service life of A-20s after the war's end was brief, apart for Brazil and few other exceptions.
Left: A-26B. The resemblance with its predecessor A-20 is evident Image from Wikimedia commons.
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