Tag Archives: Lockheed Model 10 Electra

24 February 1934

The prototype Lockheed Model 10 Electra X233Y in flight over Southern California, 1934. (James Borden Photography Collection)

24 February 1934:¹ Edmund Turney Allen,² a consulting engineer and test pilot, took the prototype Lockheed Model 10 Electra, serial number 1001, registered X233Y, for its first flight from the Lockheed Aircraft Corporation plant in Burbank, California, to the adjacent United Airport (which soon became United Air Terminal, then Lockheed Air Terminal and is now the Hollywood-Burbank Airport, BUR).

Aerial photograph of United Airport, looking west northwest, early 1930s. The Lockheed factory is just out of frame at the lower left, bordering the railroad tracks. (Burbank Public Library)

The Los Angeles Times reported:

NEW-TYPE PLANE PERFECTED

Lockheed Factory Turns Out First of “Electras,” Latest Word in Swift Transport

     The latest forward step by Los Angeles in the field of swift-aircraft manufacture, a 215-mile-an-hour, ten-passenger, low-wing monoplane built by Lockheed Aircraft Corporation, made its first appearance and took to the air in its initial test flight yesterday.

     The all-metal airliner, one of the fastest multimotored transport planes in the world and designed for economical performance by airlines enjoying little or no air-mail subsidy, was flown by Edmund T. Allen on its maiden flight from the Lockheed plant to United Airport, Burbank.

     The ship, named the Electra, is the first of nine such planes ordered by two airlines, Northwest Airways having placed an order for three and Pan-American Airways awaiting delivery on six Electras. The model follows the single-engine Lockheed Vega, Orion and Sirius models flown by Col. Charles A. Lindbergh, Wiley Post, Col. Roscoe Turner, Amelia Earhart and other noted flyers on record flights.

     The Electra’s cruising speed is in excess of 190 miles per hour. It is equipped with controllable-pitch propellers to gain maximum efficiency from its two Wasp Junior engines supercharged to develop 420 horsepower each at 5000 feet.

     The craft is equipped with advanced improvements, including new retractable landing gear, wing flaps to insure low, safe landing speed, and a radical new-type tail assembly having two small vertical fins, or rudders,instead of one large one, making for greater maneuverability.

     The Electra will be on display at United Airport, and the public, according to United Airlines officials, is invited to inspect it.

Los Angeles Times, Vol. LIII, 25 February 1934, Page 17, Columns 1 and 2

The prototype Lockheed Electra Model 10 prototype, X233Y, at Union Airport, Burbank, California, before its first flight, 24 February 1934. (James Borden Photography Collection)

The Lockheed Model 10 Electra was designed as a 10-passenger commercial transport and was a contemporary of the Boeing Model 247. This was Lockheed’s first all-metal airplane. The Electra had two engines, a low wing and retractable landing gear. The airplane was designed by Lloyd Stearman and Hall L. Hibbard.

Lockheed Model 10 Electra X233Y. (aviadejavu)

A young engineer, Clarence L. (“Kelly”) Johnson, an assistant aerodynamicist at the University of Michigan, performed the wind tunnel tests on scale models of the proposed design and recommended changes to the configuration, such as the use of two vertical fins mounted at the outboard ends of the horizontal stabilizer. This became a design feature of Lockheed airplanes into the 1950s and included the Model 14 Super Electra/Hudson, Model 18 Lodestar/PV-1 Ventura, the P-38 Lightning fighter and the L-1649 Starliner, which was produced until 1958. Johnson would become the leader of Lockheed’s legendary  “Skunk Works.”

Clarence L. "KellY" Johnson conducted wind tunnel testing of the Model 10 at the University of Michigan.
Clarence L. “Kelly” Johnson conducted wind tunnel testing of the Model 10 at the University of Michigan. Note the single vertical fin on this wind tunnel model. (Lockheed)

The prototype Electra was was used for certification testing. During a full-load test at Mines Field (now, LAX, Los Angeles International Airport) the Electra’s landing gear malfunctioned. Marshall (“Babe”) Headle, Lockheed’s chief pilot, flew the airplane back to Burbank and made a one-wheel landing. The prototype was slightly damaged but quickly repaired.

Lockheed Model 10 Electra X233Y at Union Airport, Burbank, California, before its first flight, 24 February 1934. (James Borden Photography Collection)
Lockheed Model 10 Electra X233Y at Union Airport, Burbank, California, before its first flight, 24 February 1934. (James Borden Photography Collection)
Lockheed Model 10 Electra X233Y at Union Airport, Burbank, California, before its first flight, 24 February 1934. (James Borden Photography Collection)
Passenger cabin of the Lockheed Model 10 Electra, looking forward. (James Borden Photography Collection)
Lockheed Model 10 Electra NC233Y at Northwest Airways, St. Paul, Minnesota, May 1934. (James Borden Photography Collection)
Lockheed Model 10 Electra NC233Y, Northwest Airways, St. Paul, Minnesota, 24 May 1934. (James Borden Photography Collection)
Lockheed Model 10 Electra NC233Y, St. Paul Minnesota, 24 May 1934. (James Borden Photography Collection)

After testing was competed the prototype Electra was delivered to Northwest Airways, Inc., at St. Paul, Minnesota, in May 1934. The experimental registration was changed to a standard registration, NC233Y, and it was assigned the Northwest fleet number 60.

Like the Boeing 247, the Electra was originally produced with a forward-slanting windshield to prevent instrument light reflection during night flights. This resulted in ground lighting reflections, though, and was changed to a standard, rearward slant with the fifth production airplane. NC233Y was modified by Northwestern’s maintenance staff.

Lockheed built 147 Model 10s in various configurations. The first production variant was the Model 10A. It was 38 feet, 7 inches (11.760 meters) long with a wingspan of 55 feet (16.764 meters), and height of 10 feet, 1 inch (3.073 meters). The wings had a total area of 458.3 square feet (42.6square meters). Their angle of incidence was 0°, and there were 5° 34′ dihedral.

The airplane had an empty weight of 5,455 pounds (2,474 kilograms) and a gross weight of 9,000 pounds (4,082 kilograms).

Three-view illustration of initial configuration of the Lockheed Model 10 Electra.

The Model 10A was powered by two air-cooled, supercharged, 986.749-cubic-inch-displacement (16.170 liters) Pratt & Whitney Wasp Jr. SB  9-cylinder radial engines with a compression ratio of 6:1. They were rated at 400 horsepower at 2,200 r.p.m at 5,000 feet (1,524 meters), and 450 horsepower at 2,300 r.p.m. for takeoff, using 87-octane gasoline. The SB engines were direct-drive and turned two-bladed Smith variable-pitch propellers. The Wasp Jr. SB was 3 feet, 6.59 inches (1.056 meters) long, 3 feet, 11.75 inches (1.162 meters) in diameter, and weighed 645 pounds (293 kilograms). The engines were covered by NACA cowlings.

The airplane had a cruise speed of 190 miles per hour (306 kilometers per hour) at 5,000 feet (1,524 meters) and maximum speed of 215 miles per hour (346 kilometers per hour) at 8,000 feet (2,438 meters). The service ceiling was 20,000 feet (6,096 meters) and the range at cruise speed was 750 miles (1,207 kilometers).

The prototype Lockheed Model 10 Electra, NC233Y, after cockpit windshield modifications by Northwestern Airways, Inc. (San Diego Air and Space Museum Archives)
The prototype Lockheed Model 10 Electra, NC233Y, after cockpit windshield modifications by Northwest Airways, Inc. (San Diego Air and Space Museum Archive, Catalog #: 01_00091576)

Newsreel footage of the Lockheed Model 10 prototype’s first flight, by cinematographer Alfred Dillimtash Black for Fox Movietone News, is in the collection of the Moving Image Research Collections, University of South Carolina, University Libraries, and can be viewed at: https://digital.tcl.sc.edu/digital/collection/MVTN/id/7073

The Electra was “the Lisbon plane” in the  classic 1942 motion picture, “Casablanca,” which starred Humphrey Bogart, Ingrid Bergman, Paul Henreid and Claude Rains.

Probably the best-known Lockheed Electra is the Model 10E Special, NR16020, which was built for Amelia Earhart for her around-the-world flight attempt in 1937. She took delivery of the airplane on her 39th birthday, 24 July 1936.

Amelia Earhart with her Lockheed Electra 10E, NR16020, at Burbank, 1937.
Amelia Earhart with her Lockheed Electra 10E, NR16020, at Burbank, 1937.

The prototype Lockheed Model 10 later carried U.S. registrations NC2332, NC17380, and Canadian registration CF-BRG. It was placed in service with the Royal Canadian Air Force 2 August 1940 with the serial number 7652. One of 15 Lockheed Electras in RCAF service during World War II, it was destroyed by fire at RCAF Station Mountain View, Prince Edward County, Ontario, Canada, 14 October 1941.

Statement of Accident (Royal Canadian Air Force/Canadian Warplane Heritage Museum)

¹ Most sources cite 23 February as the date of the first flight.

² Many sources (e.g., Wikipedia) state that Lockheed’s Chief Pilot, Marshall Headle, made the Electra’s first flight.

© 2023, Bryan R. Swopes

7 May 1937

Lockheed XC-35 36-353 in flight. (U.S. Air Force)

7 May 1937: First flight of the Lockheed XC-35, Air Corps serial number 36-353. Ordered by the Air Corps in 1936 as a high-altitude research aircraft, and for the development of cabin pressurization, the XC-35 Supercharged Cabin Transport Airplane was a highly modified Lockheed Electra 10A. It was the first airplane to be specifically built with a pressurized cabin.

The Army Air Corps was awarded the Collier Trophy for 1937 for the XC-35 project.

With a strengthened circular fuselage and smaller windows, the XC-35′s passenger compartment was pressurized by engine turbo-superchargers and controlled by a flight engineer. Cabin pressure could be maintained at the equivalent of 12,000 feet (3,658 meters) above sea level, at an actual altitude of 30,000 feet (9,144 meters).

A crew of three and two passengers were accommodated within the pressurized section, and there was room for another passenger to the rear of the pressure bulkhead, which could only be used at lower altitudes.

Lockheed XC-35 36-353.

The Lockheed XC-35 was powered by two air-cooled, supercharged, 1,343.804-cubic-inch-displacement (22.021 liter) Pratt & Whitney R-1340-43 (Wasp T5H1) single-row, nine-cylinder radial engines with a compression ratio of 6:1. The R-1340-43 had a Normal and Takeoff Power rating of 550 horsepower at 2,200 r.p.m. from Sea Level to 3,000 feet (914 meters), burning 92-octane gasoline. It was direct drive. The engine was 3 feet, 6.25 inches (1.073 meters) long, 4 feet, 3.50 inches (1.308 meters) in diameter, and weighed 864 pounds (392 kilograms).

Able to fly above 30,000 feet (9,144 meters), the XC-35 was later used by NACA for thunderstorm penetration research flights. In 1948 it was transferred to the Smithsonian Institution.

Lockheed XC-35 35-363. (U.S. Air Force)
Lockheed XC-35 36-353. (U.S. Air Force)

© 2017, Bryan R. Swopes

Clarence Leonard (“Kelly”) Johnson (27 February 1910–21 December 1990)

Clarence Leonard "Kelly" Johnson. (guggenheimedal.org)
Clarence Leonard “Kelly” Johnson. (guggenheimedal.org)

Clarence Leonard (“Kelly”) Johnson was born at Ishpeming, Michigan, United States of America, 27 February 1910. He was the third of five children of Peter Johnson, a stone mason, and Kjrstie Anderson Johnson. His parents were immigrants from Sweden.

C.L. Johnson, 1932 (Michiganensian)

Kelly Johnson attended Flint Central High School, graduating in 1928. After studying at a community college, Johnson transferred to the University of Michigan at Ann Arbor. He graduated in 1932 with a Bachelor of Science degree in Aeronautical Engineering (B.S.E. AeroE.). He won the Frank Sheehan Scholarship in Aeronautics, which enabled him to continue at the University to earn a Master of Science degree in Aeronautical Engineering (M.S.E.) in 1933.

Kelly Johnson started working as a tool designer for the Lockheed Aircraft Company in Burbank, California, in 1933. After transferring to the engineering department, he was assigned to the company’s Model 10 Electra project. Johnson identified a stability problem with the airplane’s design, and he was sent back to the University of Michigan to conduct a wind tunnel study which resulted in his proposal of the twin vertical tail configuration which was a characteristic of many Lockheed airplanes that followed. Johnson also served as a flight test engineer for the airplane.

A genius of aeronautical engineering and design, he was responsible for all of Lockheed’s most famous aircraft: the Lockheed Hudson and Neptune medium bombers, the P-38 Lightning twin-engine fighter, the P-80 Shooting Star, America’s first full-production jet fighter. He designed the beautiful Constellation airliner. The list is seemingly endless: The F-94 Starfire, F-104 Starfighter, U-2, A-12 Oxcart and the SR-71 Blackbird.

Clarence L. “Kelly” Johnson conducted wind tunnel testing of the Lockheed Model 10 at the University of Michigan. (Lockheed Martin)
The prototype Lockheed Model 10 Electra NX233Y during flight testing. (Lockheed Martin)
Lockheed Model 12 Electra Jr. (SDASM Catalog #: 01_00091568)
Lockheed YP-38 Lightning (U.S. Air Force)
Lockheed Model 14-N2 Super Electra Special, c/1419, NX18973. (San Diego Air and Space Museum Archive)
Lockheed Model 414 Hudson (A-29A-LO) in U.S. Army Air Corps markings. (U.S. Air Force)
Prototype Lockheed Model 18 Lodestar, NX17385. (Lockheed Martin)
Lockheed Ventura (IWM ATP 12110C)
Clarence L. “Kelly” Johnson (left) and Chief Engineering Test Pilot Milo G. Burcham, with the XC-69. (Lockheed Martin)
Lockheed XC-69 prototype, NX25600, landing at Burbank Airport. (Lockheed Martin)
The Lockheed XP-80 prototype, 44-83020, at Muroc AAF, 8 January 1944. (Lockheed Martin)
Clarence L. “Kelly” Johnson with a scale model of a Lockheed P-80A-1-LO Shooting Star. (Lockheed Martin)
Lockheed XP2V-1 Neptune prototype, Bu. No. 48237, 1945. (Lockheed Martin)
Lockheed TP-80C-1-LO (T-33A) prototype, 48-356, with P-80C-1-LO Shooting Star 47-173, at Van Nuys Airport, California. (Lockheed Martin)
Lockheed YF-94 prototype, 48-356. (See TP-80C prototype, above.) (U.S. Air Force)
Lockheed XF-104 prototype, 53-7786, photographed 5 May 1954. (Lockheed Martin)
Kelly Johnson seated in the cockpit of a prototype Lockheed XF-104 Starfighter. (Lockheed Martin)
Lockheed U-2, “Article 001” (Lockheed Martin)
Lockheed L-1049 Super Constellation prototype, NX6700, ex-L-049 NX25600. (Lockheed Martin)
The second Lockheed L-1649A Starliner, delivered to Trans World Airlnes in September 1957. (Lockheed Martin)
Lockheed EC-121T Warning Star. (U.S. Air Force)
Lockheed Model L-349 JetStar.
Lockheed A-12 60-6924 (Lockheed Martin)
Lockheed SR-71A 69-7953. (U.S. Air Force)
Clarence L. (“Kelly”) Johnson, Director of Lockheed’s Advanced Development Projects (“the Skunk Works”) with the first YF-12A interceptor, 60-6934. (Lockheed Martin)

Kelly Johnson was married three times. He married Miss Althea Louise Young, who worked in Lockheed’s accounting department, in 1937. She died of cancer in December 1969. He then married Miss Maryellen Elberta Meade, his secretary, at Solvang, California, 20 May 1971. She died 13 October 1980 of complications of diabetes. He married his third wife, Mrs. William M. Horrigan (née Nancy M. Powers), a widow, and MaryEllen’s best friend, 21 November 1980. Johnson had no children.

Kelly Johnson retired from Lockheed in 1975 as a senior vice president. He remained on the board of directors until 1980.

Clarence Leonard Johnson died 21 December 1990 at St. Joseph’s Medical Center, Burbank, California, after a long period of hospitalization. He was buried at the Forest Lawn Memorial Park in the Hollywood Hills, Los Angeles, California.

© 2018, Bryan R. Swopes