Lockheed Hudson Mk.I for RAF

Last revised September 24, 2000

In February of 1938, Lockheed undertook a preliminary study of a military version of the Model 14 Super Electra airliner. It was envisaged as an armed general reconnaissance aircraft with a secondary bombing capability. Work on a wooden mockup as well as preliminary engineering data had already begun when the British Purchasing Commission arrived in the USA in the spring of 1938 looking for combat aircraft. It just so happened that the Commission was looking for a general reconnaissance aircraft for the Royal Air Force, just the type that the Lockheed company was working on. Lockheed worked frantically to get the mockup and the engineering report ready, and the British Purchasing Commission was sufficiently impressed that Lockheed was invited to send a delegation to London for further negotiations with the Air Ministry.

The military version of the Model 14 airliner, named B14 by the company, was to be a fairly straightforward conversion of the Super Electra. It was to seat a crew of four: a pilot, a bombardier, a navigator/radio operator, and a rear gunner. It retained the wing, tail surfaces, and engines of the Lockheed 14-WF62, which was the export version of the Super Electra powered by Wright SGR-2820-F62 Cyclone engines rated at 900 hp for takeoff and 760 hp at 5800 feet. However, the B14 differed from the Super Electra in featuring a modified fuselage with nose and dorsal turrets (each equipped with a single flexible machine gun), a large bomb bay in the lower center fuselage (where the cargo hold was located on the airliner version), and a navigator's station behind the wing trailing edge fitted with a single ventral flexible aft-firing machine gun.

The RAF did not like this crew configuration for a general reconnaissance aircraft, and recommended that the navigator be relocated to a position much closer to the pilot. In addition, it was felt that the nose gun turret would probably interfere with forward vision. These suggestions were readily adopted by Lockeed, which produced a revised mockup within 24 hours. The nose turret was eliminated, and the navigator was moved forward to a position right behind the flight deck. The navigator was also given the bombardier's role, for which he would shift into the transparent nose when releasing the bombs. The radio operator took his former position behind the bomb bay, where he operated the ventral machine gun. The original dorsal gunner's position was retained.

The potential competition for the Lockheed design consisted of versions of the Boeing B-17 and the Douglas B-18. These all promised to be considerably more expensive than the Lockheed proposal and would probably not be available in sufficiently large quantities in the time needed. Another advantage for Lockheed was that the British were already well aware of the qualities of the Model 10, 12, and 14 series of commercial airliners, the first two types having been in service in the UK for over a year, with the Model 14 about to enter service.

A Lockheed team, including Courtlandt Gross, Clarence "Kelly" Johnson, Carl Squier, Richard Von Hake, and Robert Proctor, went over to the UK to negotiate with the Air Ministry. During the course of meetings between the Lockheed team and the Air Ministry, a decision was reached to replace the proposed dorsal turret with a Boulton Paul turret carrying a pair of 0.303-inch machine guns and to mount a pair of 0.303-inch machine guns in a fixed forward-firing position in the upper nose over the navigator's position. The bombload was decreased to 1600 pounds, made up of four 250-lb bombs and ten 100-lb bombs. The engines were changed to a pair of 1100 hp Wright GR-1820- G102A nine-cylinder air-cooled radials. On June 23, 1938, the Air Ministry agreed to order 200 Model B14Ls (RAF serials N7205/N7404), plus as many more that could be delivered by December of 1939, up to a maximum of 250 aircraft.

With the RAF order, Lockheed suddenly had a lot more business than it could handle. Lockheed needed a fresh infusion of cash to get the project off the ground, and borrowed $1.25 million dollars in short-term loans and raised another three million dollars by issuing more stock. The work force was drastically increased. Since Lockheed's Burbank plant had limited floor space, a good deal of the subassembly had to be farmed out to Rohr Aircraft of San Diego.

The first prototype B14L (RAF serial N7205) began flight testing at Burbank on December 10, 1938. It had no armament, but was fitted with a dummy dorsal turret. Since the aircraft was a more-or-less straightforward conversion of the existing and proven Model 14, testing went forward rapidly and relatively few problems were encountered.

In the meantime, the Australian government had ordered an initial batch of 50 Model B14S aircraft, powered by Pratt & Whitney Twin Wasp SC3-G engines.

The type was given the name Hudson Mk. I by the Royal Air Force. Deliveries to the RAF began on February 15, 1939. Forty aircraft had been built by June of 1939. Since the British government had promised to buy 50 more examples if the initial order for 200 could be delivered on time, a lot of money was riding on getting production of the Hudson going as rapidly as possible. The efforts succeeded, and the 250th Hudson had been built by October of 1939, well ahead of the deadline.

The first 200 Hudson Mk.1s were assigned British military serials N7205/N7404 (construction numbers B14L-1601/1749, 1751/1777, 1780/1803). The RAF subsequently ordered 150 more, with additional serials P5116/P5165 (c/n B14L-1805/1854) and T9266/T9365 (c/n 214-2301/2400). Another Hudson Mk.1 (R4059, c/n B14L-1804) was built as a replacement for N7260, which had been written off before delivery. They were all powered by two Wright GR-1820-G102A nine- cylinder radials, each rated at 1100 hp for takeoff and 900 hp at 6700 feet. The engines drove three-bladed, two-position propellers. The armoment consisted of a pair of 0.303-inch fixed forward-firing machine guns in the upper nose, plus a pair of 0.303-inch guns in a Boulton Paul turret (which was installed in the United Kingdom after delivery). Up to 1400 pounds of bombs or depth charges could be carried in an interal bomb bay. The normal crew was five.

Initially, Hudson deliveries to the United Kingdom were made by sea, with aircraft being put aboard ship at Long Beach, California or flown to Floyd Bennett Field, New York for partial disassembly and transatlantic shipment. Final assembly took place at the British Reassembly Division, Lockheed Ltd at Speke Airport near Liverpool.

In September of 1939, following the outbreak of war in Europe, the US Congress had passed the Neutrality Act, which specifically prohibited US citizens from delivering arms to the warring parties. This immediately halted the delivery of combat aircraft and other arms to Britain and France. However, since the loss of European business threatened to reduce funding and research for new US aircraft, the Neutrality Act was amended in November of 1939 to permit arms sales on a cash-and-carry basis. Since the British and French were paying for their planes in gold, the deliveries could resume.

In order to follow the strict letter of the Neutrality Act law, some rather farcial measures had to be employed. For example, combat aircraft sold to foreign air forces could not actually be physically transferred to their buyers on American soil. Consequently, Lockheed flew many of its newly-built Hudsons to an airfield at Pembina on the US-Canadian border with North Dakota. The Hudsons were landed on the American side of the airstrip, which extended into Canada. Once the ownership paperwork was completed, the aircraft were then towed across the border to Canada.

The Hudson proved to be easy to fly. Three-point landings were not the norm, and the aircraft usually took off and landed on its mainwheels with no more than 60 percent of its massive Fowler flaps being used on the landing approach. If flaps were extended further, loss of pitch control could take place.

All but 31 of the Hudson Mk.I aircraft were assigned to the Royal Air Force. Of these 31, two (P5163 and P5164) went to the South African government, 28 went directly to the Royal Canadian Air Force, and one (N7260) was destroyed before delivery. The RCAF machines were given Canadian serials 759/786, which corresponded to RAF serials N7344/N7350, N7352, N7354, N7355, N7356, N7360, N7370, N7371, N7375, N7380, N7381, N7373, N7382, N7384, N7385, N7383, N7387, N7385, N7386, N7388, N7389, N7390, and N7391. In RAF service, N7220 was converted into a VIP transport and N7364 became G-AGAR while serving with No. 2 Camouflage Unit.

The RAAF B14Ss powered by Pratt & Whitney Twin Wasp SCE-Gs were initaily known as Hudson Mk.Is, but were later redesignated Nudson Mk.IV.

Specification of Lockheed Hudson Mk.I

Two Wright R-1820-G102A air-cooled radial engines, rated at 1100 hp for takeoff and 900 hp at 6700 feet. Performance: Maximum speed 246 mph at 6500 feet, cruising speed 220 mph. Initial climb rate 2180 feet per minute. Service ceiling 25,000 feet. Range 1960 miles. Weights: 11,630 pounds empty, 17,500 pounds loaded. Dimensions: Wingspan 65 feet 6 inches, length 44 feet 4 inches, height 11 feet 10 inches, wing area 551 square feet. Armament: Two fixed, forward-firing 0.303-inch Browning machine guns mounted in the nose above the bombardier-s windows plus two 0.303-inch machine guns in a dorsal Boulton Paul power turret. Four 250-pound bombs or ten 100-pound bombs could be carried in an internal bomb bay.


  1. Lockheed's Made-Over Bomber, Freeman Westell, Wings, Vol 26, No. 6, p. 46 (1996).

  2. Lockheed Aircraft Since 1913, Rene J. Francillon, Naval Institute Press, 1987

  3. British Military Aircraft Serials, 1912-1969, Bruce Robertson, Ian Allen, 1969.