Lockheed twin-engine, twin-tail passenger aircraft were familiar sights at American and foreign airports during the 1930s. The most famous, which was featured prominently in movie newsreel and magazine photos, was the Electra 10E flown by aviatrix Amelia Earhart on her ill-fated round-the-world flight in 1937.
The efficacy of this aircraft series led to the U.S. Navy, Marine Corps, and Coast Guard acquiring more than 100 of the several models of the California-based manufacturer's passenger aircraft from 1936 to 1943. One of these became the first twin-engine aircraft to operate on a U.S. aircraft carrier.
In 1932 the newly reorganized Lockheed Aircraft Corporation initiated design of a twin-engine airliner.1 The prototype aircraft-with the company designation Model 10 and named Electra after one of the seven sisters of the Pleiades-first flew on 23 February 1934. The Electra was a streamlined aircraft, featuring twin Pratt & Whitney Wasp engines, semi-retractable landing gear, a twin-tail configuration, and seats for ten passengers. It was rated at a maximum speed of 202 mph with a range of 800 miles.
The Electra arrived on the scene just in time: In late 1934, single-engine passenger aircraft were forbidden from operating over the United States on scheduled flights at night or over terrain unsuitable for emergency landings. The prototype Electra was followed by 148 production aircraft between August 1934 and July 1941 in four commercial and five military variants.2
The U.S. Navy and Coast Guard each procured a single Electra in 1936. The Navy 10A aircraft was designated XR2O-1 and assigned to transport the Secretary of the Navy. The Coast Guard's 10B became the XR3O-1 and was used by the Secretary of the Treasury, the parent organization of the Coast Guard at that time.3 The Navy type symbol R indicated multi-engine transport, and O was the symbol for Lockheed (L having been assigned to the Loening firm). (The U.S. Army Air Corps procured aircraft with the primary designations C-36 and C-37.)
The subsequent Lockheed Model 12 Electra Junior was a smaller aircraft, similar to its larger sister but almost 20 percent lighter and carrying only six passengers. With the same Pratt & Whitney Wasp 450-horsepower engines, the Junior had superior performance. It was intended for use as a private executive transport and for feeder airline routes.
The prototype Model 12 flew on 27 June 1936, and was a highly successful design. Still, only 130 aircraft were produced. These included military versions provided to the Dutch Netherlands East Indies government for crew training. They were fitted with a forward-firing .303-caliber machine gun, a dorsal turret with a similar gun, and under-fuselage racks for eight 100-pound bombs.
After World War II began in the Far East in December 1941, the Dutch used these planes mainly for maritime patrol. Their losses were heavy, and only one of 36 aircraft survived. That one, flown by a Dutch cadet-pilot and four Australian sergeant pilots, flew from the East Indies to Ceylon on 8 March 1942, a distance of some 2,000 miles.4
The U.S. Navy took delivery of six Model 12A aircraft in 1937. The first was assigned the designation JO-1, with J indicating a utility aircraft. It was a seven-seat transport for use by the U.S. naval attaché in Brazil. Two six-seat variants also went to the Navy and the remaining three to the Marine Corps, all designated JO-2. An additional 12A was acquired by the Navy as the XJO-3 in October 1938. This aircraft was fitted with a tricycle landing gear for carrier trials.
The first known operation of a twin-engine aircraft from a carrier had taken place in September 1936, when a Potez 56E light transport operated on board the French carrier Béarn. The Potez was the French Navy's adaption of a six-passenger commercial aircraft, fitted with an arresting hook for shipboard trials.
In tests to determine the practicality of operating twin-engine and tricycle landing gear aircraft from carriers, on 29 August 1939, Lieutenant Commander Thruston B. Clark made 11 landings and takeoffs with the XJO-3 on board the carrier Lexington (CV-2) steaming off the California coast. According to Clark, "Admiral [William] Halsey [then a carrier division commander] came aboard to witness the tests, which went off without a hitch, and was much impressed by it all." Clark made one less landing than was scheduled "because things went so well." Interestingly, in early 1942, when naval officers began looking into the feasibility of a carrier-launched air strike on Japan with twin-engine bombers, they had no knowledge of the successful XJO-3 trials.
Another unusual role for the Lockheed 12 was that of spy plane. Beginning in February 1939, Australian flier Sidney Cotton made several photographic flights over Germany, Italy, and North Africa in a secretly modified 12A on behalf of French and British intelligence agencies. His aircraft was fitted with, alternatively, one or three cameras in the fuselage. Shutters that covered and hid the cameras were controlled from the cockpit. After the outbreak of the war, he continued his flights over German ports in his modified civilian aircraft because British military photo planes were relatively ineffective. In all, Cotton flew three successive Model 12A aircraft on spy missions.
The Model 14 Super Electra was an advanced design in the Lockheed line, with more powerful engines providing a top speed of 260 mph in some models. It first flew on 29 July 1937. Only 112 aircraft were built because the Douglas DC-3, which entered service earlier and had a larger passenger capacity, captured the relevant air transport market. Configured to carry from 10 to 14 passengers, the Super Electra was successful as both a commercial and military transport. One, owned and piloted by billionaire Howard Hughes, circled the globe in July 1938. The Navy procured a single Model 14 (XR4O-1) as a staff transport.
The next Lockheed twin-engine transport acquired by the Navy was the Model 18 Lodestar. The first to fly was a rebuilt Super Electra, which took off on 21 September 1939. Considerably larger than its predecessors, in commercial livery the aircraft was rated at 15 or 18 passengers, although using bench-type seating 26 could be carried.
With war approaching, beginning in 1940 94 of the type were acquired for Navy, Marine Corps, and Coast Guard service. Seven different variants were procured through 1943:
- XR5O-1 Coast Guard staff transport (1 acquired)
- R5O-1 Navy staff transport (2)
- R5O-2 Navy transport (1)
- R5O-3 Navy four-seat executive transport (2)
- R5O-4 Navy seven-seat staff transport (12)
- R5O-5 Navy 14-seat staff transport (41)
- R5O-6 Marine Corps 18-seat paratroop transport, some flown by Navy (35).5
The Marine aircraft were intended for paratroop training with the Corps, which established two parachute battalions as well as the structure for a parachute regiment during the war. The Marines, however, made no combat parachute jumps in World War II, and the parachute units were disbanded by early 1944.6 (The U.S. Army Air Forces also procured Model 18 aircraft with the designations C-56, C-57, C-59, C-60, and C-66.)
Lockheed's future naval aircraft would include highly successful transports, especially the GV-1/C-130 Hercules, and a long and important line of maritime patrol aircraft-the PBO Hudson, PV Harpoon and Ventura, P2V/P-2 Neptune, and P3V/P-3 Orion. But the Navy of the 1930s and 1940s flew large numbers of Lockheed twin-engine, twin-tail transports.
1. The history of Lockheed and its aircraft are best told in René J. Francillon, Lockheed Aircraft since 1913 (Annapolis, MD: Naval Institute Press, 1987).
2. Ibid., p. 120.
3. The Lockheed XRO-1 was a single-engine utility aircraft acquired by the Navy in 1931 and used by the Assistant Secretary of the Navy.
4. Francillon, p. 135.
5. Ibid., p. 191.
6. See Charles L. Updegraph Jr., U.S. Marine Corps Special Units of World War II (Washington, DC: Headquarters, U.S. Marine Corps, 1972), pp. 36-46.
