The name 'Boston III' designates different variants of the plane that were in service with the Royal Air Force, that were visually similar to some U.S. variants. In Soviet Union, the name Boston III or B-3 designated all the versions before the A-20G, including the A-20B.

In the page of Boston III we can include different variants:

the DB-7B and DB-7C in service with the RAF and characterized by the oblique cut of the nose glazing and protruding blisters on the nose sides containing four 7.62 mm machine guns; about 77 were exported from UK to the Soviet Union; the A-20A, very similar looking, apart for the blisters, wasn't exported in Soviet Union.

These early versions were characterized by an unique large lateral exhaust pipe.

A-20B were also known as Boston or B-3 in Soviet Union although they were not in service with the RAF, but they are described in a separate page because they were well distinguishable for the stepped front glazing.

The A-20C, successive to the A-20B and well distinguishable from this for the return to the oblique cut of the nose glazing, was visually distinguishable from DB-7B/C/A-20A versions for details of the exhaust tubes.

A-20C were built as Boston III and IIIA for the Great Britain, but the most part of them, 690 planes, were exported to the Soviet Union or retained in U.S. after the attack on Pearl Harbour.

They could have had the typical protruding blisters on the nose sides containing four 7.62 mm machine guns; all the weapons were of 7.62 mm caliber, the dorsal defensive mg was twin; the rearward-firing machine guns in the nacelles were deleted.

Often the Soviet A-20C appear with flat nose sides and two fixed 12.7 mm machine guns as A-20B; it is unclear if they were built so, or it was a Soviet modification.

Different arrangements of the exhaust tubes and of the supercharger intakes, with or without the extensions for the air filters over the cowling, were possible.

A defect of Bostons was their vulnerability, particularly to attacks from behind by German fighters, and led to high losses. The lethality of their small 7.7 or 7.62 mm machine guns was insufficient to create a good defense, and they had a too limited field of fire.

The crew of the DB-7/Boston III/A-20A-B-C in England and the United States consisted of three people: a pilot, a navigator-bombardier and a radio operator-rear gunner that actioned both the dorsal weapons and the one firing through the ventral hatch.
In the Soviet Union, a further gunner was added for the ventral weapon, bringing the crew to 4 men.

The 7.62 Browning were often replaced by a Browning 12.7 mm or an UB; often the small machine guns in the nose blisters were replaced with two UB 12.7 mm.

In Soviet Union, many B-3s were rearmed with the UTK-1 turret with a Soviet UBT 12.7 mm machine gun with K-8T or PMP sight and a prominent side magazine with 200 rounds.

The primitive British Wimperis D-8 gunsight, which was put on export planes instead of the highly advanced Norden for secrecy reasons, was replaced by Soviet OPB-1R (daytime) or NKPB-4 or 7 (for night bombing) sights.

The planes were often equipped with a Soviet radio compass, whose aerial was hidden in a drop radome posed on the back or, rarely, on the nose of the plane.

Right: UTK-1 turret with UBT 12.7 mm machine gun. Note the wide magazine on the right side of the gunner.

'White 1/AL-417'

Drawing by Tapani Tuomanen

Boston III 'White 1', ex-British AL-417, captured by Germans in September 1942.

The most striking characteristic is the partially visible British rounder on the fuselage; anyway, it is ikely that the painted was stripped by Germans to look for the proof of the British service of the plane, and was not visible when the plane few in Soviet service.

The paints could be the original British ones instead of the US imitations.

Images from the web

'White 5' of 15 ORAP

A-20C/Boston III 'White 5' of 15 ORAP, VVS KBF (Independent Recognition Air Regiment, Airf Force of the Baltic Fleet) shot down in Finland in August 1943. It was rearmed with an UTK turret and probably equipped with two AFA-33 cameras in the bomb bay, shooting through holes in the doors.

The plane was probably a ex-British Boston because of the absence of seral on the tail;the two light areas of the second photo suggest A-20C-style exhaust pipes.

This plane "white 5" was shot down by Kullervo Lahtela 23.8.1943 over Estonia and then the plane was shipped to Helsinki. What happens to this aircrft later is unknown.

Images from the web

'White 36'

A-20C 'white 36'. Strangely the plane hasn't nor the US serial, nor the British one. The contrast of the camouflage is unusually strong, but the pattern is the usual British one. The paint is unusually uniform despite that it should be at least one year aged and that the plane was modified to install the turret. It could be that the contrast is due to an uniform ageing of the original paints.

Codes, if any, are in black and hardly readable. It seems to read 1193xx on the tail and x2 on the nose, but it could be an illusion.

'Red/green 5'

Boston III/A-20C 'Red 5' s/n 41-19128 captured by Germans. The shortened serial was often painted in black on camouflaged planes.

A visual characteristic of this plane is the previous number 5 on the fin, overpainted with Russian green.

Images from Red Stars 4 of Geust and Petrov ed. Apali and from the web.

'Red 5/BZ590'

Boston III s/n bears both the US serial 41-19608 and the British BZ-590 registration suggesting an A-20C-BO built for the Great Britain, visually similar to DB-7B. the plane is marked with a large 5 on its rudder, presumably red with a thin outline of lighter color.

In the photo, the the Regiment C.O., HSU V.A.Khoroshilov, is receiving the report by the flight instructor of an unidentified ZAP (reserve Aviation Regiment) in Central Asia in August 1942.

The plane was painted with the US imitation of the British camouflage. Red stars with thin black outline are recognizable.

The original marks were deleted with the proper paints.

Image from Red Stars 4, of geust and Petrov, ed. Apali

'White 4' of 16 ODRAP

A-20C 'White 4', s/n hardly readable, xxx234, 41-19234 or 42-33234 are possible and compatible with lists of serials sent to Soviet Union. They appear painted in black; it can't be a yellow darkened by an orthocromatic film because the tips of the propellers appear light. The markings with white outline are datable after the August 1943.

An interesting characteristic is the radiocompass radome, installed on the side of the nose instead of the more usual dorsal position. Besides, an unusual bulge is visible on the side of the plate of the machine guns in the nose, possibly related to a rearmament with UB.

Image: archive Sammler

http://ava.org.ru/rap/16.htm