The Lockheed Model 12 Electra Junior, more commonly known as the Lockheed 12 or L-12, is an eight-seat, six-passenger all-metal twin-engine transport aircraft of the late 1930s designed for use by small airlines, companies, and wealthy private individuals. A smaller version of the

Lockheed Model 10 Electra The Lockheed Model 10 Electra is an American twin-engined, all-metal monoplane airliner developed by the Lockheed Aircraft Corporation in the 1930s to compete with the Boeing 247 and Douglas DC-2. The type gained considerable fame as one was ...

, the Lockheed 12 was not popular as an airliner but was widely used as a corporate and government transport. Several were also used for testing new aviation technologies.

Design and development

After Lockheed had introduced its 10-passenger Model 10 Electra, the company decided to develop a smaller version which would be better suited as a " feeder airliner" or a corporate executive transport.O'Leary 2001, p. 1. At the same time, the U.S. Bureau of Air Commerce had also sensed the need for a small feeder airliner and announced a design competition for one. In order for a candidate to qualify for the competition, a prototype had to fly by June 30, 1936.O'Leary 2001, p. 3. Lockheed based its candidate, which it named the Model 12 Electra Junior, around a scaled down Electra. It would carry only six passengers and two pilots but would use the same Pratt & Whitney R-985 Wasp Junior SB

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...

s as the main Electra version, the 10A. This made it faster than the Electra, with a top speed of at . Like the Electra, the Model 12 had an all-metal structure, trailing-edge wing flaps, low-drag NACA engine cowlings, and two-bladed

controllable-pitch propellers In marine propulsion, a variable-pitch propeller is a type of propeller with blades that can be rotated around their long axis to change the blade pitch. Reversible propellers—those where the pitch can be set to negative values—can al ...

(later changed to constant-speed propellers). It also had the Electra's twin tail fins and rudders, which were becoming a Lockheed trademark. The

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Marti ...

was a conventional tail-dragger arrangement, with the main wheels retracting backwards into the engine

nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...

s; as was often the case with retractable gear of the period, the wheel bottoms were left exposed in case a wheels-up emergency landing was necessary, or the pilot simply forgot to deploy his novel landing gear.Bowers 2000, p. 1. As in the Electra and the

Boeing 247 The Boeing Model 247 is an early United States airliner, and one of the first such aircraft to incorporate advances such as all-metal ( anodized aluminum) semimonocoque construction, a fully cantilevered wing, and retractable landing gear.

, the Model 12's main

wing spar In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles (or thereabouts depending on wing sweep) to the fuselage. The spar carries flight loads and the weight of the wings while on t ...

passed through the passenger cabin; small steps were placed on either side of the spar to ease passenger movement. The cabin had a lavatory in the rear. Although the standard cabin layout was for six passengers, Lockheed also offered roomier, more luxurious layouts for corporate or private owners. The new transport had its first flight on June 27, 1936, three days before the competition deadline, at 12:12 PM local time, a time deliberately chosen for the Model 12's number. As it turned out, the other two competition entries, the

Beechcraft Model 18 The Beechcraft Model 18 (or "Twin Beech", as it is also known) is a 6- to 11-seat, twin-engined, low-wing, tailwheel light aircraft manufactured by the Beech Aircraft Corporation of Wichita, Kansas. Continuously produced from 1937 to Novemb ...

and the Barkley-Grow T8P-1, weren't ready in time for the deadline, so Lockheed won by default. The "Electra Junior" name did not catch on in the way that the original Electra's name had. Most users simply referred to the aircraft by its model number, as the Lockheed 12. The original Lockheed 12 version, with Wasp Junior engines, was the Model 12A. Almost every Lockheed 12 built was a 12A or derived from the 12A. There was also a Model 12B, using Wright R-975-E3 Whirlwind radials, but only two of this model were built. Although Lockheed had also announced a Model 12F, powered by

Wright R-760 Whirlwind The Wright R-760 Whirlwind was a series of seven-cylinder air-cooled radial aircraft engines built by the Wright Aeronautical division of Curtiss-Wright. These engines had a displacement of 756 in³ (12.4 L) and power ratings of 225-35 ...

seven-cylinder radials, and a Model 12M, powered by Menasco six-cylinder

inline engines In aviation, an inline engine is a reciprocating engine with banks of cylinders, one behind another, rather than rows of cylinders, with each bank having any number of cylinders, although more than six is uncommon. The major reciprocating-engi ...

, neither of these versions reached production.

Operational history

Lockheed 12A Electra Junior in Flight over Houston

Even though the Lockheed 12 had won the government's feeder airliner competition, most of the airlines rejected it, and very few Lockheed 12s were used as airliners.O'Leary 2001, p. 4. One notable airline user was the newly renamed Continental Air Lines, which had a fleet of three Lockheed 12s that ran on its route between

Denver Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the United ...

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

and

El Paso El Paso (; "the pass") is a city in and the seat of El Paso County in the western corner of the U.S. state of Texas. The 2020 population of the city from the U.S. Census Bureau was 678,815, making it the 23rd-largest city in the U.S., the ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

in the late 1930s. Another was British West Indian Airways Ltd., which flew the Lockheed 12 on Caribbean routes in the

Lesser Antilles The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc bet ...

during the mid-1940s. The Lockheed 12 proved much more popular as a transport for company executives or government officials. Oil and steel companies were among the major users. A number were purchased as military staff transports by the

United States Army Air Corps The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical ri ...

, which designated the type as the C-40, and by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

, which used the designation JO, or in one peculiar case, R3O-2. With the arrival of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

, many civilian Lockheed 12s were requisitioned by the U.S. Army and Navy, Britain's

Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) an ...

, and the

Royal Canadian Air Force The Royal Canadian Air Force (RCAF; french: Aviation royale canadienne, ARC) is the air and space force of Canada. Its role is to "provide the Canadian Forces with relevant, responsive and effective airpower". The RCAF is one of three environ ...

. Two civil Lockheed 12s ordered by British Airways Ltd. were actually intended for covert military reconnaissance flights. Sidney Cotton modified these aircraft for aerial photography and in civilian guise, overflew and surreptitiously photographed many German and Italian military installations during the months preceding World War II.Bowers 2000, p. 5. The main military user of the Lockheed 12 was the

Royal Netherlands East Indies Army Air Force The Royal Netherlands East Indies Army Air Force ( nl, Militaire Luchtvaart van het Koninklijk Nederlands-Indisch Leger, ML-KNIL) was the air arm of the Royal Netherlands East Indies Army in the Dutch East Indies (now Indonesia) from 1939 unti ...

, which bought 36. Sixteen of these were the Model 212, a version created by Lockheed for training bomber crews, which had a caliber machine gun in an unpowered, partly retractable

gun turret A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechani ...

on top of the fuselage, a second .303-caliber machine gun fixed in the nose, and bomb racks under the wing center section that could hold eight bombs. The other 20 aircraft were transport versions. Several Lockheed 12s were used as technology testbeds. The U.S.

National Advisory Committee for Aeronautics The National Advisory Committee for Aeronautics (NACA) was a United States federal agency founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its assets ...

(NACA) bought two, adding a center vertical fin to each of them to test stability improvements. One of the NACA Lockheed 12s was used to test "hot-wing"

deicing Deicing is the process of removing snow, ice or frost from a surface. Anti-icing is the application of chemicals that not only deice but also remain on a surface and continue to delay the reformation of ice for a certain period of time, or preve ...

technology, in which hot exhaust air from the engines was ducted through the wing's leading edge to prevent ice accumulation.Bowers 2000, p. 4. Three other Lockheed 12s were used to test

tricycle landing gear Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', arranged in a tricycle fashion. The tricycle arrangement has a single nose wheel in the front, and two or more main wheels slightly aft of the center of gravity. Tricycle ...

."Tri-gear experiments."
''Air Classics,'' December 2001. Retrieved: January 16, 2010. These had their normal landing gear replaced by a non-retracting version with a large nosewheel and with the main wheels shifted further back on the engine nacelles. (The tailwheel from the normal conventional gear was retained.) The gear was non-retractable because there wasn't room within the structure to stow it in retracted position. Streamlined fairings were placed on the gear to reduce drag. One of the tricycle gear Lockheed 12s went to the U.S. Navy as the XJO-3 and performed carrier landing tests on the to study the suitability of a twin-engined tricycle-gear aircraft for carrier operations. Another went to the U.S. Army as the C-40B, and still another was retained by Lockheed for its own testing; both of these were eventually converted back to the normal landing gear configuration. Milo Burcham flew a Lockheed 12A in the 1937 Bendix Trophy Race from

Burbank Burbank may refer to: Places Australia * Burbank, Queensland, a suburb in Brisbane United States * Burbank, California, a city in Los Angeles County * Burbank, Santa Clara County, California, a census-designated place * Burbank, Illinois, ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

Cleveland Cleveland ( ), officially the City of Cleveland, is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located in the northeastern part of the state, it is situated along the southern shore of Lake Erie, across the U ...

Ohio Ohio () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty U.S. states, it is the List of U.S. states and territories by area, 34th-l ...

. This 12A had extra fuel tanks in the cabin, allowing it to save time by making the entire trip non-stop. The 12A came in fifth at an average speed of ; this was an impressive performance, since the first and fourth-place winners were both privately owned

Seversky P-35 The Seversky P-35 is an American fighter aircraft built by the Seversky Aircraft Company in the late 1930s. A contemporary of the Hawker Hurricane and Messerschmitt Bf 109, the P-35 was the first single-seat fighter in United States Army Air Cor ...

fighters. Another Lockheed 12A, owned by Republic Oil Company and named ''The Texan'', was modified by aviator

Jimmie Mattern James Joseph Mattern (March 8, 1905 – December 17, 1988) was an American aviator. Mattern undertook a number of aviation world records, including twice attempting to break the world record for aerial circumnavigation set by Wiley Post ...

for a round-the-world flight attempt. Mattern filled the 12A's cabin with fuel tanks and removed the cabin windows and door; the crew would enter the aircraft via a cockpit hatch. The aircraft was denied a U.S. permit for the flight following the Earhart incident; however, it was pressed into action in September 1937 in a long range search effort for

Sigizmund Levanevsky pl, Zygmunt Lewoniewski , birth_date = , death_date = , birth_place = St. Petersburg, Russian empire , death_place = Arctic Ocean , image_size = , allegiance = , branch = Soviet Army before 1925Soviet Air Force ...

, who crashed somewhere between the North pole and

Barrow, Alaska Utqiagvik ( ik, Utqiaġvik; , , formerly known as Barrow ()) is the borough seat and largest city of the North Slope Borough in the U.S. state of Alaska. Located north of the Arctic Circle, it is one of the northernmost cities and towns in the ...

. "The Texan" was outfitted as a luxury transport afterward, and lost in a hangar fire in January 1938. Lockheed built a total of 130 Lockheed 12s, ending production in 1941. With the arrival of World War II, Lockheed concentrated its production efforts on more advanced military aircraft, such as the Hudson bomber and the

P-38 Lightning The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps by the Lockheed Corporation, the P-38 incorporated a distinctive twi ...

twin-engined fighter. The Lockheed 12's market was left to the

, thousands of which would eventually be produced. A number of Lockheed 12s have survived to the present day, mostly in private hands. Several of these are still flying.

Variants

Civil models

;Model 12A :Powered by two Pratt & Whitney R-985 Wasp Junior SB radial engines. 70 built."Lockheed 1 to J."
''Aerofiles.'' Retrieved: January 8, 2010.''FAA Type Certificate Data Sheet TC 616.'' ;Model 12B :Like 12A, but powered by two Wright R-975-E3 Whirlwind radial engines. This was a normal civil model, but the only two built (serial numbers 1228 and 1249) went to the

Argentine Army The Argentine Army ( es, Ejército Argentino, EA) is the land force branch of the Armed Forces of the Argentine Republic and the senior military service of Argentina. Under the Argentine Constitution, the president of Argentina is the command ...

.Bowers, Peter
"History of the Lockheed 12A, p. 2."
'Flight Journal'', April 2000. Retrieved: 15 July 2010. ;Model 12-25 :Last two civilian Model 12's produced (serial numbers 1293 and 1294), same as 12A but with Pratt & Whitney R-985 Wasp Junior SB3 engines.

Military models

All of these were based on the Model 12A and used the same engines. ;C-40 : U.S. Army Air Corps five-passenger transport; prototype (serial 1247) converted from company owned 12A, two others built, redesignated UC-40 in January 1943. ;C-40A :U.S. Army Air Corps transport with mixed passenger/cargo interior; 10 built, plus one converted from C-40B, redesignated UC-40A in January 1943. ;C-40B :U.S. Army Air Corps testbed for testing fixed

; one built, converted to a normal C-40A in 1940. ;C-40D :Eleven civil Model 12As impressed by the

U.S. Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

in 1942, with standard six-passenger interior. Redesignated UC-40D in January 1943. ;JO-1 : U.S. Navy five-passenger transport; one built.McKillop, Jack
"Lockheed JO Electra Junior, R2O Electra, R3O Electra and Electra Junior."
''microworks.net.'' Retrieved: January 8, 2010. ;JO-2 :U.S. Navy and

Marine Corps Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refle ...

six-passenger transport; five built. ;XJO-3 :U.S. Navy testbed with fixed tricycle gear, used for carrier landing tests and airborne radar trials; one built. ;R3O-2 :One civil Model 12A impressed by the U.S. Navy in 1941. (This was an anomalous designation, since the Navy had already used R3O for the Model 10 Electra.)"Lockheed K to Lockheed-Martin."
''Aerofiles.'' Retrieved: January 8, 2010. ;Model 212 :Bomber trainer with bomb racks and gun turret atop aft fuselage; prototype (serial 1243, reserialed 212-13) converted from company owned 12A, 16 others built, one prototype and 16 for the

. ;Model 12-26 :Military transport version of the Model 212; 20 built for the Royal Netherlands East Indies Army Air Force.

Operators

Civilian

Braniff Airline Pilots Watching a Lockheed 12A Electra Junior

* Aeronorte * Aerovias Brasil * Associated Airlines (Australia) * British West Indian Airways Ltd. * British Airways Ltd. (a front for the espionage of Sidney Cotton) * Continental Air Lines (formerly Varney Air Transport) *

Mercer Airlines (Burbank, CA) Pacific American Airlines was a United States charter airline headquartered in Burbank, California. Its predecessor was formed in 1946 as Airplane Charter by Mercer and renamed to Mercer Airlines in 1955. DeWight W. Mercer sold the company, was ...

* Cruzeiro do Sul *

(NACA) * Panair do Brasil * Canadian Department of Transport * Brazilian Ministry of AeronauticsBowers, Peter
p. 3
/ref> *

Santa Maria Airlines Santa Claus, also known as Father Christmas, Saint Nicholas, Saint Nick, Kris Kringle, or simply Santa, is a legendary figure originating in Western Christian culture who is said to bring children gifts during the late evening and overnigh ...

Military

; *

Francillon 1982, p. 128. ; *

Brazilian Air Force "Wings that protect the country" , colours = , colours_label = , march = Hino dos Aviadores , mascot = , anniversaries = 22 May (anniver ...

Francillon 1982, p. 130. ; *

; ; *

Indonesian Air Force The Indonesian Air Force ( id, Tentara Nasional Indonesia Angkatan Udara (TNI-AU), literally "''Indonesian National Military-Air Force''") sometimes shortened as IDAF / IdAF, is the aerial branch of the Indonesian National Armed Forces. The I ...

Francillon 1982, p. 133. ; *

Royal Netherlands Air Force , colours = , colours_label = , march = ''Parade March of the Royal Netherlands Air Force'' , mascot = , anniversaries = , equipment ...

; *

South African Air Force "Through hardships to the stars" , colours = , colours_label = , march = , mascot = , anniversaries = , equipment ...

; *

United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through ...

Aircraft on display

* A Model 12A (Canadian registration CF-CCT, Lockheed construction number 1219) is on display at the Canada Aviation Museum in

Ottawa Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core ...

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

. This aircraft was operated by Canada's

Department of Transport The Department for Transport (DfT) is a department of His Majesty's Government responsible for the English transport network and a limited number of transport matters in Scotland, Wales and Northern Ireland that have not been devolved. The ...

from 1937 until 1963 and surveyed the route of the

Trans-Canada Airway The Trans-Canada Highway (French: ; abbreviated as the TCH or T-Can) is a transcontinental federal–provincial highway system that travels through all ten provinces of Canada, from the Pacific Ocean on the west coast to the Atlantic Ocean ...

. In 1937 it made the first same-day flight from

Montreal Montreal ( ; officially Montréal, ) is the second-most populous city in Canada and most populous city in the Canadian province of Quebec. Founded in 1642 as '' Ville-Marie'', or "City of Mary", it is named after Mount Royal, the triple- ...

Quebec Quebec ( ; )According to the Government of Canada, Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is ...

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the most populous city in the province, the 2021 Canadian census recorded 662,248 people in the city, up from 631,486 in 2016. Th ...

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost Provinces and territories of Canada, province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include ...

, making five stops en route. "Lockheed L-12A Electra Junior."
''Canada Aviation and Space Museum''. Retrieved: January 17, 2010. * A former U.S. Army Air Corps C-40A (U.S. Army serial number 38-540, U.S. civil registration N93R, Lockheed construction number 1257) is on display at the Yanks Air Museum in Chino,

. * A Royal Netherlands Air Force Lockheed 12A c/n 1306 is on static display at the Soesterberg Nationaal Militair Museum in

Soesterberg Soesterberg is a town in the Dutch province of Utrecht. It is a part of the municipality of Soest, and lies about 5 km northeast of Zeist, on the road between Amersfoort and Utrecht. It was the location of Soesterberg Air Base Histor ...

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

* A former Royal Netherlands Air Force Lockheed 12-26 c/n 1313 is on static display at Arlanda Flygsamlingar, near Stockholm-Arlanda airport. Swedish airline Airtaco acquired the aircraft in 1953 for newspaper freights. Registration SE-BXU was reserved but was never accepted into the registry. Donated to Arlanda Flygsamlingar in 1990. * An Indonesian Air Force Lockheed 12A registration number T-303 is on static display at Suryadarma Air Force Base in

Subang Regency Subang Regency (Sundanese script: , Latin: Kabupatén Subang) is a regency (''kabupaten'') in West Java province, Indonesia. The Regency is bordered by the Java Sea in the north, Indramayu Regency in the east, Sumedang Regency in the southeast, ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

Specifications (Model 12A)

Notable appearances in media

A Lockheed 12 appeared as the French airliner in the climactic final scene from the 1942 film '' Casablanca''."'Of all the gin joints...'"
''Air Classics,'' December 2001. Retrieved: January 17, 2010. (The aircraft carries the

Air France Air France (; formally ''Société Air France, S.A.''), stylised as AIRFRANCE, is the flag carrier of France headquartered in Tremblay-en-France. It is a subsidiary of the Air France–KLM Group and a founding member of the SkyTeam global airl ...

seahorse logo, although Air France did not actually operate the type 12A). A "cut-out" stood in for a real Lockheed 12 in many shots. No real aircraft appeared in the movie. Half and quarter scale models were used instead. Lockheed 12s have also appeared in movies as stand-ins for the Electra 10E used by

Amelia Earhart Amelia Mary Earhart ( , born July 24, 1897; disappeared July 2, 1937; Presumption of death, declared dead January 5, 1939) was an American aviation pioneer and writer. Earhart was the first women in aviation, female aviator to fly solo acro ...

in her round-the-world flight attempt. Two played this role in the NBC 1976 TV miniseries ''

'', and another did so in the 2009 movie '' Amelia''.Collins, Mike
"The 'Amelia' movie's airplane."
''AOPA Aviation Summit,'' October 6, 2009. Retrieved: January 8, 2010.

References

Notes

Citations

Bibliography

* Blankenburg, Kent
"Lockheed's Baby Electra".
''Flight Journal,'' April 2000. * Bowers, Peter
"History of the Lockheed 12A."
''Flight Journal,'' April 2000. * Davisson, Budd

''airbum.com,'' 1989. * Francillon, René J
''Lockheed Aircraft Since 1913.''
London: Putnam, 1982. .
"Inspection Handbook Part 4, pp. 31–32."
''Federal Aviation Administration.'' * O'Leary, Michael
"Junior Bomber."
''Air Classics,'' December 2001. * O'Leary, Michael
"Shining Stars (Part Two)."
''Air Classics,'' December 2001 Another detailed history of the Lockheed 12. (Note: The online article has combined it with the subarticle: "Junior Bomber".) *

''Flight,'' Volume XXIX, Issue 1415, February 6, 1936, p. 148. Brief announcement and description of the Lockheed 12, published before the type's first flight.
"Type Certificate Data Sheet TC 616."
''Federal Aviation Administration.''

External links

{{USN utility aircraft Electra Junior 1930s United States airliners 1930s United States civil utility aircraft Low-wing aircraft Aircraft first flown in 1936 Twin piston-engined tractor aircraft Twin-tail aircraft