The Lockheed Hudson light bomber of World War 2 was a military development of the Model 14 Super Electra commercial airliner. Although the Hudson saw relatively little combat in American hands during World War 2, the aircraft was extensively used by British, Australian, and New Zealand air forces. The Hudson was actually the first American-designed combat aircraft to destroy an enemy aircraft in actual combat, although it was with a Royal Air Force crew that this was achieved. When Lend-Lease was introduced in 1941, the Hudson was assigned the designation A-28 and A-29 in the USAAF attack series. This was primarily for administrative purposes, since relatively few Hudsons served with USAAF units. However, an A-29 was the first Army Air Force aircraft to score a successful attack on a German U-boat.
The Model 14 Super Electra airliner first appeared in 1937. It was designed by a team headed by Hall Hibbard and Clarence "Kelly" Johnson to compete against the new Douglas DST/DC-3 commercial transport. The aircraft was of low-wing, twin-engine, twin-tailed format, and bore an obvious family resemblance to the earlier Model 10 Electra but was somewhat larger. The transport featured a highly-loaded wing of relatively small span and area, chosen so as to achieve a high cruising speed. Fowler flaps were adopted which were designed to reduce landing speeds but also augmented effective wing area to reduce the takeoff distance. This marked the first use of Fowler flaps on a production aircraft. The fuselage was deeper than that of previous Lockheed airliners, making it unnecessary for passengers to step over the wing truss as was necessary in the Lockheed Models 10 and 12. Cabin length could accommodate either 14 passengers in single seats on each side of the central aisle or ten to eleven passengers with a galley and a cabin attendant. The wing had optional fixed wing slots (later made standard), fully-feathering propellers, and integral fuel tanks.
The prototype (c/n 1401, civilian registry X17382) flow for the firat time on July 29, 1937 with Marshall Headle at the controls. It was powered by a pair of Pratt & Whitney Hornet S1E-G air-cooled radial engines, each rated at 875 hp for takeoff and 750 hp at 7000 feet.
To attract customers, Lockheed offered a broad choice of powerplants, including two versions of the Pratt & Whitney Hornet, five versions of the Wright Cyclone, and one version of the Pratt & Whitney Twin Wasp. On November 15, 1937, an Approved Type Certificate was awarded, covering the Hornet S1E-G-powered Model 14-H and the Hornet S1E2-G-powered Model 14-H2.
A total of 52 Hornet-powered Super Electras were built between July 1937 and June 1940. 20 of them were Model 14Hs (including the prototype, eight aircraft for Northwest Airlines, one for Guinea Airways, and ten for the Polish airline LOT. 32 were Model 14-H2s (18 for Trans-Canada Air Lines, with the remainder going to five other airlines and one to a private customer).
After being operated briefly by TACA, c/n 1401 was taken back by Lockheed and modified as a prototype for a proposed cargo version. A hunchbacked fuselage was fitted to make the aircraft capable of carrying bulkier loads, and a large loading door was provided. Redesignated Model C-14H-1, the aircraft was tested briefly by the the Army Air Corps at Wright Field. However, the Army found the Model C-14H-1 unsuitable for military service, and the aircraft was converted back to Model 14-H standard and was returned to passenger service in Brazil as PP-AVB and was later sold to an airline in Nicaragua as AN-TAB.
The Model 14-WF62 was produced for the export market. It was powered by a pair of Wright Cyclone SGR-1820-F62 radials, each rated at 900 hp for takeoff and 760 hp at 5800 feet. The rudders were modified with static balances to prevent tail flutter. 21 examples of this version were built, with 11 going to KLM and KNILM beginning in February of 1938, eight to British Airways, and the last two going to Aer Lingus in Ireland in May of 1939.
The Model 14-N was powered by Wright Cyclone engines of the G-series, which offered a takeoff rating of 1100 hp and a maximum rating of 900 hp between 6000 and 6700 feet. The four examples built were all sold to private owners. Two of them had GR-1820-G105 engines and one had -G105A engines. They were fitted with deluxe interiors for use as executive transports. The last one (c/n 1419, civil registry NX18973) was designated Model 14-N2 and was specially built for Howard Hughes. It was powered by GR-1820-G102 engines. This aircraft was fitted with extra fueselage tanks to supplement the four integral tanks in the wing, increasing total fuel tapacity to 1844 US gallons. Additional radio and navigational equipment, as well as flotation bags and extra supplies, were installed in the fuselage. Five crew members could be accommodated, three forward and two aft of the cabin fuel tanks. This aircraft was used by Howard Hughes to carry out a round-the-world flight in July of 1938. Hughes and his crew left Floyd Bennett Field in New York on July 10, 1938 and returned to the same field four days later via Paris, Moscow, Omsk, Yakutsk, Fairbanks, and Minneapolis. Total flying time for the 14,672 miles was 91 hours 14 minutes 10 seconds, with an average speed of 206.1 mph.
The first launch customer for the Super Electra was Northwest Airlines, which first introduced it into service on the run between the Twin Cities (Minneapolis/St. Paul) and Chicago in October of 1937. There were early problems with tail flutter, which required that balanced tail surfaces be retrofitted. Unfortunately, there were three Super Electra crashes while in Northwest Airlines service, which caused the airline to dispose of its entire Super Electra fleet during the summer of 1939 and replace them with DC-3s. The only other US airlines to use the type were Santa Maria Airlines (just one aircraft) and Continental Airlines (two examples).
The Super Electra had somewhat greater success overseas, with six major carriers acquiring 21 Hornet-powered and 53 Cyclone-powered aircraft. The first overseas customer was the Dutch airline KLM and its East Indies subsidiary KNILM. The high performance of the Super Electra was especially useful on the long Amsterdam-Batavia route. British Airways also acquired four Super Electras for use on its routes from the UK to West Africa and on to South America. British Airways also acquired the Super Electra, using one of its first examples to fly Prime Minister Neville Chamberlin to the Munich conference on September 15, 1938. The British Airways Super Electras were primarily used on European routes including services to Berlin and Warsaw. LOT, LARES, Aer Lingus, and Regie Air Afrique also ordered Super Electras. Trans-Canada Air Lines ordered 16 examples.
Japan turned out to be the largest user of the Super Electra. Thirty Super Electras were sold to the Tachikawa Hikoki KK (Tachikawa Aeroplane Co Ltd of Japan, which acted as an agent for Nihon Koku KK (Japan Air Transport Co. Ltd.). This airline was later renamed Dai Nippon Koku KK (Greater Japan Air Lines), and became the largest commercial user of the Super Electra. This version of the Super Electra was known as Model 14-WG3B, and was powered by two Wright Cyclone GR-1820-G3B radials, rated at 900 hp for takeoff and 840 hp at 8000 feet. The Tachikawa company also obtained a license to build a version of the Super Electra in Japan. Production for the Imperial Japanese Army was undertaken both by Tachikawa and by Kawasaki Kokuki Kogyo KK (Kawasaki Aircraft Engineering Co. Ltd. These companies respectively built 64 and 55 aircraft between 1940 and 1942. They were powered by Mitsubishi Ha-26-I (900 hp Army Type 99 Radial Model 1) engines. In Japanese army service, they were designated Army Type LO Transports, and were operated as military transports during the Pacific War. The Allies assigned the code name Thelma to the Japanese-built version and the name Toby to the civilian versions purchased from Lockheed.
A single example was delivered to the US Navy as XR4O-1 in October of 1938. It was a staff transport version of the Model 14-H2 powered by two 850 hp Pratt & Whitney R-1690-52 radials Only one was built.
During the early days of the Pacific War, four Model 14-WF62s from the KNILM were flown to Australia to avoid capture by the Japanese. These planes were purchased by the USAAF for service with the ADAT (Allied Directorate of Air Transport). One crashed almost immediately, but the other three (c/ns 1414, 1442, and 1443) were assigned the USAAF designation of C-111 and assigned the US military serials 44-83233/83235 and the Australian civilian registrationx VH-CXI/VH/CXK
In many respects, the Super Electra was more advanced than the Douglas DC-2 which had a similar capacity. It had the advantage of being equipped with more powerful engines which gave it a twenty percent higher cruising speed. When compared to the DC-3, which had a 50 percent larger capacity and similar set of engines, the Super Electra had a similar speed advantage but was less economical. The wider cabin and larger capacity of the DC-3 made it a much more comfortable plane for passengers than was the relatively narrow cabin of the Super Electra. Consequently, except for those airlines which placed a high value on exceptional cruise performance, the Super Electra was at a distinct disadvantage when competing against the Douglas transports. Its belated entry into the commercial market turned out to be an additional problem that could never be overcome and only 112 Super Electras were built between July 1937 and June of 1940.
Engines: Two Wright Cyclone SGR-1820-F62 radials, each rated at 900 hp for takeoff and 760 hp at 5800 feet. Performance: Maximum speed 250 mph at 5800 feet, cruising speed 215 mph, initial climb rate 1520 feet per minute. Normal range 850 miles, maximum range 2125 miles. Service ceiling 24,500 feet. Weights: 10,750 pounds empty, 15,650 pounds normal loaded, 17,500 pounds maximum. Dimensions: Wingspan 65 feet 6 inches, length 44 feet 4 inches, height 11 feet 5 inches, wing area 551 square feet.