The political crisis at the end of the 1930s made the RAF command realise that the British aviation industry would not be able to produce a sufficient number of modern aircraft in the short term. Therefore, in April 1938, a purchasing committee was sent to the USA to organise the supply of the most needed types of military aircraft. Among other things, 250 Hudson aircraft were purchased. It was based on the Lockheed 14 Super Electra passenger and transport plane, the prototype of which was flown on 29 June 1937. Lockheed Aircraft Corporation did not build or develop military aircraft, however, its constructors envisaged a quick conversion of civil aircraft into military ones. Therefore, Lockheed built a mock-up of a transport and combat aircraft in four days, which attracted the attention of the British. They concluded that it would make an excellent maritime patrol aircraft. The designer of the aircraft was Clarence “Kelly” Johnson. The aircraft was initially designated B-14, later B-141 and L-214 “Hudson”.
A great advantage of the Hudson was its spacious fuselage, accommodating 4 crewmen and 1,500 kg of bombs. In the nose part of the fuselage could be installed 2 fixed machine guns. The British requested an armament upgrade with 2 machine guns housed in a spherical Boulton-Paul turret on the back of the fuselage. The aircraft was powered by two Wright GR-1820-G102A radial engines. All armament was of British production, calibre 7.7mm (.303). The reinforcement of the armament reduced the bomb payload to 1,400 lb (635 kg). On 25.07.1938 the British signed a contract for the delivery of Hudson Mk.I aircrafts with the delivery date to December 1939. Lockheed immediately started to prepare the serial production and the first serial aircraft was flown on 10 December 1938. In February 1939 the first Hudsons were delivered to Great Britain. The first delivered aircraft were used for trials and crew training. Lockheed delivered the ordered 250 aircraft two months ahead of schedule. Of these, 28 were delivered to the RCAF (serials: 759-786) and a further 3 were delivered to the SAAF in 1940.
In April (according to other sources – in May) 1939, the crews of No. 224 Squadron RAF began regular patrols over the North Sea with these aircraft. The operation of the RAF patrol squadrons became particularly important at the beginning of the Second World War. For Britain, maintaining control of its sea lanes of communication was vital at the time. In early 1940, radars for the detection of submarines, ASW Mk.I, began to be installed on the Hudsons for the first time. Aircraft of this type actively participated in numerous clashes over the sea, achieving considerable success in combat in the early stages of the war. Hudson became the first RAF aircraft to shoot down a German plane operating from the British Isles, it was on 8 October 1939. Hudsons participated in the evacuation of troops at Dunkirk in May-June 1940, they attacked the German battleship Sharnchorst in June of the same year. They were used by the RAF in special task squadrons: 161 in Europe and 357 in Burma.
Hudsons were in fact multi-purpose aircraft, used as long-range maritime patrol, anti-submarine, air transport, diversion group drops, weather reconnaissance and transport aircraft. Between 1938 and 1943, 2,941 aircraft of all versions were built. Hudson was the basis for the development of the new Lockheed Ventura aircraft.
Variants and serials:
Mk.I – the first version built to RAF order, powered by Wright GR-1820-G102A engines producing 809 kW (1100 hp). 351 examples were built for the RAF (N7205-N7404, P5116-P5165, T9266-T9365 and R4059)and 50 examples for the RAAF (A16-1 – A16-50).
Mk.II- externally did not differ from the Mk.I, its construction was strengthened and having constant-speed propellers. Built 20 copies for the RAF (T9366-T9385) and 50 copies for the RAAF.
Mk.III – version combining airframe of Mk.II version with Wright GR-1820-G205A engines with 882 kW (1200 hp). The aircraft could be armed with machine guns installed in the windows of the cargo cabin and was adapted for flights over the sea. 428 examples were built. RAF serials: T9386-T9465, V8975-V8999, V9020-V9069, V9090-V9129, V9220-V9254. AE485-AE608 and AM930- AM953.
Mk.III (LR)- III with extra fuel tanks, increasing maximum capacity from 2,438 to 3,892 litres.
C.Mk III – transport aircraft VJ416 and VJ421.
Mk.IIIA- similar to the Mk.III version, but equipped with Wright R-1820-87 engines with 882 kW (1200 hp). Delivered to the United Kingdom and British Commonwealth countries. The aircraft were also supplied to the US military aviation under the designation A-29 and to the US Navy aviation as PBO-1. 800 examples were built, including 384 examples of the military transport variant designated A-29A.
Mk.IV – designation of aircraft used in RAAF (A16-51 – A16-100), which received Pratt & Whitney “Twin Wasp” engines S3C-G with 772 kW (1050 hp). RAF serials: (AE609 – AE638).
Mk.IVA- designation for 52 aircraft in the RAAF, delivered under Lend Lease.
Mk.V- a version similar to the Mk.III, but with Pratt & Whitney “Twin Wasp” engines S3C4-G with 882 kW (1200 hp). 409 examples were built, serials AE639 -AE657 and AM520 – AM702.
Mk.V (LR) – V with extra fuel tanks (AM703 – AM909)
Mk.VI- version similar to Mk.III, but equipped with Pratt & Whitney R-1830-67 engines with 882 kW (1200 hp). 450 examples were built.
C Mk.VI- designation for Mk.VI transport aircraft used in the RAF, did not have armament.
A-28- equivalent to the Mk.IV and Mk.IVA versions intended for RAAF, which received 52 aircraft (A16-101 – A16-152).
A-28A- designation of the Mk.VI version intended for the RAF (EW873-EW972 and FK381-FK730). USSAF serials: 42-6582 – 42-6681 and 42-46937 – 42-47286.
A-29 -similar to the A-28 version, powered by 882 kW (1200 hp) R-1820-87 engines. 416 were built for the RAF (BW361-BW766, BW768-BW777 and FH167-FH366), 153 went to the USAAF as RA-29 (41-23223 – 41-23628, 41-23630 – 41-23639 and 41-36968 – 41-37167) and 20 to the US Navy as PBO-1 BuNos 03842 – 03861.
A-29A – a version of the A-29 adapted to the role of a transport aircraft. 384 were built for the RAF as Mk.IIIA, several were used by the USAAF as RA-29A (according to other sources – equivalent to the Mk.VI version, intended for the USAAF). Serials: BW767 41- 23629; FH367-FH466, 41-37168 – 41-37267; and FK731-FK813, 42-47287 – 42-47369.
A-29B – designation of 24 aircraft of the A-29A version in the photo reconnaissance variant.
AT-18 – a training version delivered to the USAAF, equipped with R-1820-87 engines of 882 kW (1200 hp) and a Martin gun turret used for on-board gunner training. 217 examples were built (42-55568 – 42-55784).
AT-18A- a version similar to the AT-18 with R-1820-87 engines, designed for navigator training. Supplied to the USAAF (42-55485 – 42-55567), 83 were built.
C-63 – provisional designation of the A-29A version.
B-14S – designation of one aircraft delivered to Sperry, used as a test aircraft for new equipment.
Francillon, René J.: Lockheed Aircraft since 1913
Profile Publications 253 – Lockheed Hudson Mks I To VI