History of the Lockheed 12A

Flight Journal, Apr 2000 by Bowers, Peter

The Lockheed Model 12A made between 1936 and '41-"Electra Junior"-is one of those very good airlanes that because of various circumstances slipped through the cracks of history and has never had the recognition that it deserves. Timing had a lot to do with it, and it did not build up an impressive airline or military record, as would have been expected of a fast twinengine design; nor did it make any notable record flights. The numbers produced are respectable, though; 130 built. This did not quite match the production of its famous predecessor, Lockheed's Model 10 Electra (149 built), but it far exceeded the 75 pioneer Boeing 247s. It could not match the larger Douglas DC-2 (192) or the DC-3, which had reached 400 civil versions bv the time Model 12A production was ended. More than 10,000 DC-3s, however, were made by the end of WW II.

Company history

In 1912, brothers Alan and Malcolm Loughead-automobile mechanics in San Francisco, California-designed their Model G three-place seaplane and formed the Alco Hydro-Aeroplane Co. to manufacture it. During 1916, in Santa Barbara, California, they formed the Loughead Aircraft Manufacturing Co., and it survived into 1921. Malcolm Loughead then left the company, changed the spelling of his name to "Lockheed," and made a fortune by introducing hydraulic brakes for automobiles. Alan used the new name spelling when he founded the new Lockheed Aircraft Co. in Hollywood, California, in 1926.

After a move to nearby Burbank, the new firm prospered with its line of sleek, single-engine monoplanesthe Vega, Sirius, Altair and Orion. Many famous fliers set records in these speedy Lockheeds. Alan was then caught up in the big aviation conglomerate boom of 1929, and his company became a division of the Detroit Aircraft Corp. in July 1929. Lockheed airplanes continued to sell well, but in 1931, Detroit Aircraft succumbed to the Great Depression and took Lockheed down with it. Oddly, Lockheed was the only division of Detroit Aircraft that was still making money at the time. Nevertheless, the factory was closed, but all tooling and some unfinished airplanes and spare parts were left intact.

In June 1932, a group of California investors bid $40,000 for the defunct company and acquired its assets valued at $129,961. Their first order of business was to complete and sell the 22 pre-bankruptcy airplanes still in the plant; then they started on a new design for the new era of aircraft that was just beginning.

Model 10 Electra

The result was a twin-engine, 10-passenger, all-metal transport, the Model 10 Electra. Previous Lockheed models had been named after heavenly bodies and carriedl progressive model numbers from the Model 1 Vega of 1927 to the final Model 9 Orion. The new Electra was a logical follow-on, although it was produced by what was really a different company. No design detail from the old Lockheed firm was carried over to the new one.

Model 12A

Electra Junior

The Electra Junior Model 12A (there was no plain Model 12) was similar in outline and construction to the Model 10, but was smaller and slimmer. With the same 400hp engines as the lower-powered versions of the Model 10, it was notably faster and attained a top speed of 225mph at 5,000 feet and a cruising speed of 202mph at 9,600 feet-11mph faster than the Model 10's top speed.

The all-metal structure was of conventional 24ST aluminum alloy. Even the control surfaces were metal-skinned when equivalent designs were still using fabric. Trim tabs operable from the cockpit were built into each elevator; later, sheet-metal tabs that could be adjusted from the ground were added to the trailing edges of each rudder and to the right aileron.

The wing center section to a point outboard of the engine nacelles was integral to the fuselage, and there were large trailing-edge flaps in the non-removable outer wing panels. References differ as to the airfoils used; some say a Clark Y-18 is at the wing root and a Clark Y-09 is at the tip; others say that NACA 23016 and 23009 airfoils are used at the root and tip respectively.

A notable disadvantage for the passengers, inherited from both the Model 10 and the Boeing 247, was that the main wing spar passed through the cabin. Small steps on each side of it simplified the crossing, but it was still a nuisance.

The spar position also affected the seating, which, in the six-passenger version had two rows of three seats on each side of a center aisle and one seat on each side ahead of the spar and two behind it. This irregular seat pattern also affected the window spacing.

Lockheed planned to use the model 12A both as a feeder airliner and as an executive transport, and interiors with lounges, desks and other required customer custom features were options.

Pilot and copilot sat at dual controls in a separate forward cockpit, and there was a lavatory at the rear of the cabin. The entry door was at the left rear of the cabin, and there were two baggage compartments-one in the nose cone and one aft of the lavatory. The then conventional landing gear featured main wheels that retracted aft into the engine nacelles, leaving nearly half of each wheel exposed. The main gear used two notably different wheel/tire combinations-31 -inch Hayes 3100Ms with medium-pressure streamlined tires, or fat, low-pressure Goodyear 31x12x6-- inch Airwheels suitable for soft terrain.