Boston

II— Original designation for later

French DB-7s; later redesignated Havoc I. Boston

III— The initial British order for 300 DB-7Bs was followed by the transfer of 240 French-ordered DB-73s built by Douglas, and 240 that Douglas sub-contracted to Boeing. Tankage increased from the DB-7A's 240 U.S. gallons to

394 gallons to allow bomber operations over occupied Europe from England. Starting in mid-1941, many Boston Ills were drafted into the U.S. Army Air Forces.

Boston //M—Later DB-7Bs procured for Britain via Lend-Lease were identified by the U.S. Army as A-20C and by Britain as Boston IIIA because of their differences from the all-British Boston III.

Boston IV—U.S. Army A-20Js, complete with American armament and coloring; 169 delivered to the R.A.F.

Boston 1/—Ninety U.S. Army A-20Ks delivered to the R.A.F.

U.S. Designations—There were several experimental and one-off variants of the U.S. Army A-20 and P-70 models, but only significant production versions will be detailed here. When the U.S. gave "popular" names to military aircraft for public discussion in October 1941, the A-20s and P-70s were given the existing British name of Havoc.

A-20—An improved DB-7A with side-mounted turbo-superchargers on 1,700hp military R-2600-7 engines (as distinguished from the civil-designated engines of the export models). Original armament was four .30-caliber machine guns in the nose, two flexible .30s in the rear cockpit, a flexible .30 in a ventral tunnel and a fixed .30 in each engine nacelle firing rearward. Normal bomb load was 16 100-pound bombs or four 250-pounders. Self-sealing, 394-gallon fuel tanks were an

Douglas Raf Boston 20j

innovation for an American

The British Havoc IVis a U.S. Army A-20 J with the original Army serial number on the fin painted out. Note the lengthened Plexiglas nose, power turret and 500-pound bomb on the wing rack.

innovation for an American warplane.

The turbo proved to be troublesome, so it was removed (since a plane intended for low-altitude work didn't need the high-altitude benefits of such an installation). The first A-20 was converted to the XP-70 night-fighter prototype, and three others became XF and YF-3 photoplanes. The remaining 59 A-20s were converted to P-70s.

A-20A—& further 123 improved models ordered on the same June 30,1939, contract as the A-20s, but all were delivered with R-2600-11 engines without turbos.

A-20B—Improved A-20A with DB-7 nose, which was its principal recognition feature.

A-20C—Production models similar to the DB-7B except for their U.S. equipment; 375 were built by Douglas as A-20C-D0 and 140 by Boeing as A-20C-B0.

A-20G— Major production A-20; 2,850 were built with solid noses and R-2600-23 engines. Early versions had four 20mm cannon in the nose, but these were replaced by four to six .50-caliber machine guns starting at A-20G-5. From A-20G-20 and on, the single .50-caliber gun in the rear cockpit was replaced by a pair of .50s in a Martin-powered turret, and a single .50 replaced the .30 in the ventral tunnel. Internal bomb load was 2,000 pounds, but an additional 2,000

pounds could be carried on four wing racks. Gross weight increased to 25,700 pounds.

A-20H— Similar to late A-20Gs but used 1,700hp R-2600-29 engines; 412 built.

A-20J—The 450 A-20Js featured a lengthened Plexiglas bomber nose that contained two fixed .50-caliber guns and the famous Norden bomb sight. These were "Lead Bombers" that sighted the target for other A-20s that released their bombs when signaled by the leader.

A-20K—This was the final model of the A-20 series, with the last of the 413 built delivered September 20,1944. The airframe was similar to the A-20H, but it was equipped as the A-20J.

F-3 Series—The seventh A-20 was converted to the XF-3 photographic plane, still with turbos. The bomb racks were removed and a T-3A camera was installed in the bomb bay, but the defensive armament was retained. Two other A-20s became YF-3s without the turbos. In 1944, 46 A-20Js and A-20Ks were converted to F-3As and saw action in Europe.

P-70 Series— Sixty A-20s were re-equipped as matte-black night fighters and redesignated P-70. These had radar in a solid nose and four 20mm cannon in a pack under the bomb bay. Engines were non-turbo R-2600-11s. The 39 P-70A-1s were A-20Cs with improved radar and six to

The British Havoc IVis a U.S. Army A-20 J with the original Army serial number on the fin painted out. Note the lengthened Plexiglas nose, power turret and 500-pound bomb on the wing rack.

eight .50-caliber guns in a belly pack. The A-20C defensive armament was retained. The 65 P-70A-2s were A-20Gs that were equipped as the P-70A-1s except for the deletion of flexible guns and the change to a glossy black finish. The P-70B-2s were modifications of 105 A 20Gs and A-20Js. The single P-70B-1 was an experimental model.

U.S. Navy BD Series—After testing of a former A-20 as the XF-3, the same airplane was stripped of armament and turbos, refitted with R-2600-3 engines and delivered to the U.S. Navy as the BD-1 (Bomber, first model from Douglas, initial configuration) for utility work, such as target towing. It was followed by eight A-20Bs that were designated BD-2.

NOTE: Since the Nye drawings contain production figures, dimensions and performance data, the text concentrates on model designations and the differences between them.

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