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Lockheed L.14 Super Electra / Sky Zephyr / 214 Hudson / 414 Hudson / A-29 / A-29 / PB-1 / AT-18
Kawasaki Type 1


Designed to compete against the DST/ DC-2/DC-3 series being developed by the Douglas company, the Lockheed 14 Super Electra failed to be any significant competition, due to its smaller capacity. Of the same general configuration as the earlier Lockheed 10 Electra, it differed by having a much deeper fuselage accommodating a maximum of 14 passengers, a mid-set wing, and introduced integral fuel tanks in the wing, Fowler-type trailing-edge flaps, fully-feathering propellers and, at a later stage of production, fixed wing slats. These improvements, combined with powerful engines and high wing loading, gave the Super Electra excellent performance but, by comparison with the important and larger-capacity Douglas DC-3, it was less efficient in operation.

First flown in prototype form on 29 July 1937 powered by two 760hp Wright Cyclone radial engines, and certificated on 15 November 1937, initial deliveries were made shortly afterwards.

A British Purchasing Commission vi-sited the United States in April 1938, intent on acquiring a substantial number of American military aircraft. Lockheed executives and designers got together when they knew the British team was on its way looking for warplanes and in ten days and nights drawings were produced, and a wooden mock-up constructed, of the Model 14 in its converted form of a reconnaissance bomber.

Suitably impressed Lockheed officials met Air Ministry chiefs in London, and on June 23, 1938, a contract was signed for the building of 175 aircraft, with as many more as could be delivered by December 1939, up to a maximum of 250.

Named Hudson for RAF service, the first example (N7205) made its initial flight on December 10, 1938. Despite problems with tooling, the 250th machine was rolled out at Burbank over seven weeks ahead of schedule, thanks to staff increases and three shift working.

Initially Hudsons were delivered crated aboard ship, the first arriving at Liverpool Docks on February 15,1939, and then assembled at nearby Speke airport, where Lockheed established a subsidiary firm to undertake the rapidly increasing work consequential to the numbers of Hudsons arriving. By the summer of 1940, this amounted to over 200 aircraft. A British installation, when the Hudsons arrived, was a Boulton & Paul power-operated dorsal gun-turret housing two .303-in Browning machine guns.


In November 1940, because Britain needed aircraft urgently, seven Hudsons were flown from Newfoundland to Ireland. This led to the founing of the Atlantic Ferry Service. Pilots were flown from Britain to Newfoundland. There each of them obtained a new airraft and flew it to Britain. By Christmas Eve 1943 1000 had been ferried across the Atlantic.


Main differences to the civil passenger ver-sion was the glazed nose position, dorsal turret and the bomb bay within the centre fuselage. In addition to the dorsal turret armament, Hudsons carried twin .303-in Browning guns fixed to fire forward from the top of the forward fuselage, and provision for two Vickers ‘K’ guns, one each side in beam positions. On earlier models the bomb load was 750 lb, but later variants were capable of carrying up to 1,400 lbs of bombs or depth charges.

The Hudson I was powered by two 745.2kW Wright GR-1820-G102A Cyclone engines driving Hamilton-Standard two-position propellers. It first entered service with Coastal Command, RAF in mid-1939. The British order for 250 Mk Is was increased to 350, followed by a contract for 20 Mk IIs with Hamilton-Standard Hydromatic constant-speed propellers, 414 Mk IIIs following.

The Hudson III represented the first major revision, having 1,200hp / 894kW GR-1820-G205A Cyclone engines with Hydromatic propellers and a retractable rear-firing ventral gun position. Large numbers of the Hudson III were delivered to the RAF under Lease-Lend (resulting in the use of the USAAF designation A-29) with 894kW Wright R-1820-87 Cyclone engines. Like earlier Hudsons, the Mk III was basically a maritime-patrol bomber and reconnaissance aircraft, but A-29A were fitted with benches for troop carrying. A-29/29A were also used by the USAAF and by the US Navy (as PBO-1).

The Hudson III armament consisted of a maximum bomb load of 1,600lb (726kg) comprising four 250lb (113kg) and six 100lb (45kg) bombs; two fixed Browning 0.303in machine guns in upper nose with 500rpg; one optional Vickers 0.303in machine gun in retractable ventral hatch with 500 rounds; two optional Vickers 0.303in beam machine guns in rear fuselage with 500rpg; two Browning 0.303in machine guns in dorsal Boulton Paul turret with 1,000rpg.

Initially the Mk IIIs had little advantage in range, but after some 150 had been built, extra fuel tanks were fitted, and on November 11, 1940, seven Hudson Mk IIIs flew direct from Gander, Newfoundland, to Aldergrove, Northern Ireland, in 10.5 hours. From then on all Hudsons were flown across the Atlantic on their delivery flights.

One Hudson Mk III was presented to the RAF free, the materials for this aircraft (T9465) having been supplied by Lockheed 'gratis' while employees gave their time free. This particular aeroplane was named Spirit of Lockheed Vega Employees, and was handed over to the British Ambassador in front of assembled Lockheed staff. This machine was allotted to 269 Squadron.

At the end of January 1940, Hudsons were the first aircraft in RAF Coastal Command to be fitted with air to surface vessel (ASV) radar, which was to prove so effective against sub-marines when trying to locate them at night and in bad weather.

Hudsons also flew top secret Scrutator flights between Britain and Sweden. These operations involved taking items of freight, mail and often passengers to Stockholm, while on the return flights, the supply of Swedish ball-bearings, made to a very high standard and vital to British war production, was main-tained. Passengers were also flown back from Sweden - diplomats, escaped Allied prisoners of war and even people who had managed to escape from the clutches of the Gestapo.

Hudsons used on Scrutator were specially converted Mk IIIs and came under the control of BOAC and, although camouflaged, carried civil registrations coming under the BOAC Loch class. Four Hudsons flew this crossing.

The Hudson III was the first aeroplane to be fitted to carry the British-developed Mk I airborne lifeboat. This lifeboat was first used operationally in May 1943 by an RAF air/sea-rescue squadron to rescue the crew of a downed bomber in the North Sea.

In RAF service the Hudson Mk III was followed by the Mk IIIA, first type to be sent under the Lend-Lease scheme.
The Hudson IV was produced for the RAAF, with the ventral gun removed but received a D/F loop aerial in a transparent blister. The Air Corps assigned the A-28 designation to a contract for 52 aircraft to be delivered to the Royal Australian Air Force. Although U.S. serial numbers were given to the A-28s, none entered service with the U.S. Army Air Corps. All were delivered to the RAAF under the designation Hudson Mk.IVA and given RAAF serial numbers A16-101 to A16-152.

Thirty Hudson Mk IVs were diverted to the RAF from an Australian contract, followed by 309 Mk Vs and 450 Mk VIs, all these variants having 1,200hp Pratt & Whitney R-1830-SC3G Twin Wasp radials. The Hudson V for the RAF had R-1830-S3G4G engines driving Hamilton-Standard two-position propellers and a retractable ventral gun (as fitted to the Mk III).

The final version was the Hudson VI (designated A-28 by the USAAF) which was convertible to troop transport or cargo carrier with the turret removed. An improved version, designated A-28A, was built for export to the British Commonwealth under Lend-Lease agreements.

By 1943 RAF Hudsons were active in the Mediterranean and Middle East areas, having already flown convoy patrols the previous November to help cover the Allied landings in North-Africa.

The Royal Australian Air Force received 247 Hudson’s between January 1940 and May 1942 in several versions.

Although 800 were ordered for the RAF, only 382 were delivered, the remainder going to the USAAF as the A-29, while some ended up with the US Navy as PBO-1 patrol bombers operating in the Caribbean area on anti-submarine duties, USAAF machines did not usually have the power-operated turret, but instead a single .50-in gun was installed on a flexible mounting in an open position with a shield for the gunner's back. The A-29 could carry a 1,600 lb bomb load, and on July 7, 1942, the German submarine U-701 was attacked and sunk by one of these aircraft. US Navy PBO-1s sank two German U-Boats, both during March 1942.

Orders for Hudsons were not only for the RAF, US Army Air Corps, US Navy and Australia, but also the air forces of Canada, New Zealand, and Nationalist China.




A total of 119 was licence-built in Japan by Kawasaki for use by the Imperial Japanese Army. These, powered by 671kW Mitsubishi Ha-26-l radial engines, were designated Army Type LO Transport and were later allocated the Allied code name 'Thelma'. The Japanese army introduced the first cargo transport, the Kawasaki Type 1, in 1941. The aircraft was a military version of the 13-passenger Lockheed 14 airliner and it had a maximum payload of only 3 metric tons.

After withdrawal from combatant service with the RAF, USAAF and US Navy, the Hudson continued to be used for miscellaneous duties, including transport, air/sea rescue, training, target-towing, etc.

The Lockheed AT-18 was an advanced trainer based on the Lockheed Hudson. The USAAF placed an order for 300 AT-18s on 8 May 1942. All 300 aircraft were powered by 1,200hp Wright R-1820-87 engines. Production was split into two blocks. 217 aircraft were produced as AT-18-LO gunnery trainers, equipped with a Martin dorsal turret armed with twin 0.50in machine guns, while the remaining 83 aircraft were produced as AT-18A-LO navigational trainers. These aircraft had the turret removed and had space for the pilot, the instructor and three students.

The Hudson can claim a list of firsts including:
The first Allied aircraft to shoot down an enemy while operating from the British Isles.
The first aircraft to capture a U-boat. U-570 surrendered to a No.269 Squadron Hudson on 27 August 1941.

By the time production ended in mid 1943, a total of 2,941 examples had been built, only 112 were built by Lockheed.

L.14 Super Electra
Engines: 2 x 760 hp Wright Cyclone
Length: 44.2 ft (13.4 m)
Wing span: 65.6 ft (19.9m)
Weight empty: 10,300 lb (4,670 kg)
Max cruise speed: 230 mph (370 kph)
Ceiling: 24,000 ft (7,300 m)
Range: 2,125 miles (3,400 km)
Crew: 2
Pax cap: 12

Sky Zephyr
Engines: 2 x Pratt & Whitney, 850 hp
Pax cap: 8
Speed: 260 mph

L.14-H Super Electra
Engines: 2 x Pratt & Whitney Hornet S1E-G radial, 652kW
Max take-off weight: : 7938 kg / 17500 lb
Empty weight: 4672 kg / 10300 lb
Wingspan: 19.96 m / 65 ft 6 in
Length: 13.51 m / 44 ft 4 in
Height: 3.48 m / 11 ft 5 in
Wing area: 51.19 sq.m / 551.00 sq ft
Max. speed: 398 km/h / 247 mph
Ceiling: 7405 m / 24300 ft
Range: 3315 km / 2060 miles

Hudson I
Engines: two Wright GR-1820-G102A Cyclone, 1100 hp / 745.2kW
Propellers: Hamilton-Standard two-position.
Max take-off weight: 7938 kg / 17500 lb
Empty weight: 5276 kg / 11632 lb
Wingspan: 19.96 m / 65 ft 6 in
Length: 13.51 m / 44 ft 4 in
Height: 3.61 m / 11 ft 10 in
Wing area: 51.19 sq.m / 551.00 sq ft
Max. speed: 396 km/h / 246 mph / 214 kt
Service Ceiling: 2323 m / 7620 ft
Ceiling: 7620 m / 25000 ft
Range: 3150 km / 1957 miles / 1703 nm
Armament: 4 x 7.7mm machine-guns, 635kg of bombs
Crew: 6

Hudson II

Engines: two 745.2kW Wright GR-1820-G102A Cyclone
Propellers: Hamilton-Standard Hydromatic constant-speed

Hudson III
Engines: 2 x 1,200hp / 894kW GR-1820-G205A or R-1820-87 Cyclone
Fuel: Aviation Gasoline 100 Octane
Wing Centre Section Tanks (x4): 536 Imp Gal / 2,437 lt / USG
Propeller: Three bladed Hamilton Standard hydromatic constant speed
Propeller diameter: 10' 6" (3.20m)
Wingspan: 65' 6" / 19.69 m
Length: 44' 3.75" / 13.50 m
Wing Area: 551 sq. ft / 51.18 sq. m
Height: 10' 10.5" / 3.32 m
Empty weight: 12,100 lb / 5,488 kg
Maximum Takeoff weight: 19,500 lb / 8,845 kg
Maximum Speed: 219 knots / 252mph / 406km/h
Cruise Speed: 170 knots / 196mph / 315km/h at 8000 ft.
Landing speed 72 mph.
Service ceiling 24,500 ft
Maximum bomb load: 1,600lb (726kg)
Armament: 2 x Browning 0.303in machine guns / 500rpg; 1 x optional Vickers 0.303in machine gun / 500 rounds; 2 x optional Vickers 0.303in machine guns / 500rpg; 2 x Browning 0.303in machine guns / 1,000rpg.

Hudson IIIA
Engines: 2 x 1,200hp / 894kW GR-1820-G205A Cyclone

Hudson IV
Engines: 2 x 1,200hp Pratt & Whitney R-1830-SC3G Twin Wasp radials

Hudson IVA

Hudson V
Engines: 2 x 1,200hp Pratt & Whitney R-1830-S3G4G Twin Wasp
Propellers: Hamilton-Standard two-position

Hudson VI / A-28
Engines: 2 x 1,200hp Pratt & Whitney R-1830-SC3G Twin Wasp radials

Engines: Two Pratt & Whitney R-1830-45 Twin Wasp radial engines of 1,000 hp each
Span: 65 ft. 6 in.
Length: 44 ft. 4 in.
Height: 11 ft. 10 in.
Max weight: 22,350 lbs.
Maximum speed: 280 mph
Cruising speed: 224 mph
Range: 2,100 statute miles
Service ceiling: 27,000 ft.
Armament: Four .30-cal. machine guns (two fixed in the nose and two in the turret) plus 1,000 lbs. of bombs
Serial numbers: 41-23171 to 41-23222 (RAAF: A16-101 to A16-152)

A-29 Hudson
Engines: 2 x Wright R-1820-87 Cyclone 9, 1184 hp / 894kW
Length: 44.324 ft / 13.51 m
Height: 11.909 ft / 3.63 m
Wing span: 65.486 ft / 19.96 m
Wing area: 551.009 sq.ft / 51.19 sq.m
Max take off weight: 20504.3 lb / 9299.0 kg
Weight empty: 12826.5 lb / 5817.0 kg
Max. speed: 220 kts / 407 kph
Cruising speed: 178 kts / 330 kph
Service ceiling: 26493 ft / 8075 m
Cruising altitude: 14993 ft / 4570 m
Wing load : 37.31 lb/sq.ft / 182.0 kg/sq.m
Range: 1347 nm / 2494 km
Armament: 5x MG cal.30 (7,62mm ), 726kg / 1,600 lb bomb load,

A-29A / PBO-1
Engines: 2 x 894kW Wright R-1820-87 Cyclone
Bomb load: 1,600 lb

AT-18 Hudson
Engines:    2 x Wright R-1820-87, 1200 hp
Length: 44' 4" / 13.5 m
Wingspan: / 65' 6" / 19.9 m
Gross Weight: 19,300 lb / 8,752 kg
Max Speed: 272 mph / 438 km/h / 236 kt
Crew: 5
Known serial numbers: 42-55568 / 42-55784

AT-18B Hudson

Kawasaki Type 1
Engines:  2 x 671kW Mitsubishi Ha-26-l radial
Maximum payload: 3000 kg



Lockheed Hudson




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