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Model 10 Electra / C-35 / Army UC-36A / Navy R2O

Lockheed's innovative twin-engine Model 10 Electra, with retractable landing gear and twin fins and rudders, helped establish the company's line of commercial passenger aircraft. The 10-passenger all-metal plane flew for the first time on February 23, 1934. Northwest Airlines was the first airline to use the plane. In the late 1930s, eight U.S. airlines flew the plane as did European, Australian, Canadian, and South American customers. Model 10 Electras were used for long-distance flights, and Major James "Jimmy" Doolittle flew an Electra from Chicago to New Orleans in five hours 55 minutes in 1936-two hours quicker than the previous fastest time. Amelia Earhart disappeared in an Electra on her round-the-world attempt.

The Model 10 Electra was followed by the Model 12 Electra Junior executive transport in 1936 that seated six passengers with a two-person crew. Many Model 12s were used by the military, and the National Advisory Committee on Aeronautics (NACA) used a Model 12 to evaluate a wing deicing system that used hot air from the engine exhaust.

Amelia Earhart, nicknamed "Lady Lindy" because of her achievements comparable to those of Charles Lindbergh, is considered "the most celebrated of all women aviators." Her accomplishments in the field of aviation inspired others and helped pave the ways for those that followed. Earhart wanted to be the first of either gender to fly around the world at its widest, close to the equator. She acquired the most advanced long-range, non-military aircraft available--a Lockheed Model 10E Electra. The all-metal, two-engine plane had been reconfigured with extra fuel tanks replacing the passenger seats, allowing the plane to travel farther between refuelings. Howland Island, a tiny island in the Pacific Ocean, 2,556 miles (4,113 kilometers) away from New Guinea, was the most dangerous stop of the trip. Earhart never reached her destination, disappearing on 02 July 1938 somewhere off the coast of the island. A large search party was quickly organized, but no remains of the crew and the plane were ever found.

There are many theories surrounding the controversial disappearance of the plane on July 2, 1937. The most commonly accepted theory is that the fliers got lost, ran out of gas, and went down somewhere in the Pacific Ocean. However, as war between the United States and Japan was imminent, there were rumors that Earhart had been on a spy mission for the United States and was supposed to photograph Japanese military installations. This theory says that she crash-landed and was captured by the Japanese, who imprisoned or executed her. A third theory was that her disappearance was staged to allow the U.S. Navy to conduct a search in the South Pacific.

The XC-35 was the world's first airplane specifically constructed with a pressure cabin. In the summer of 1936, the Air Corps contracted for a single Lockheed Electra Model 10-A with extensive modifications. The plane, designated XC-35 by the Army, was intended for use as a high-altitude research and pressurized cabin test plane. As a result, the basic Electra fuselage was redesigned with a near circular cross section to better withstand the stresses of pressurization. Next, the large passenger windows were replaced with much smaller slit windows. The interior was split into two sections: the forward pressurized section had room for three crewmen and two passengers. The aft section, behind the pressure bulkhead had room for one additional passenger but could only be used at lower altitudes (below 12,000 feet).

Besides the pilot and copilot, the XC-35 carried an engineer who controlled the pressurization and high altitude research equipment. The XC-35 was fitted with a pair of Pratt & Whitney XR-1340 radial engines. These 550-hp engines were turbo-supercharged to deliver the necessary high-altitude performance. The plane was designed to fly at altitudes above 30,000 feet.

The first successful pressurized cabin airplane was the Junkers Ju 49, which flew to over 41,000 feet in May 1929, piloted by Willi Neuenhofen. The Ju 49, strictly experimental, had a small pressurized "capsule" with vision portholes for its pilot inserted into the structure of the aircraft. As for the United States, the death of balloonist Hawthorne Gray in 1927 had profoundly affected the engineering community at Wright Field, Ohio, and, under the leadership of Carl Greene, they devoted increasing attention to examining the potentiality for pressurized cabins. Greene and research associate John Younger designed a special pressurized cabin for use with a modified Lockheed Model 10 Electra twin-engine transport, using engine-driven air compressors.

The Lockheed XC-35 was delivered to Wright Field, Ohio, in May 1937. It first flew later that year, with a cabin that operated at a pressure of 9.5 psi, affording its passengers the ability to fly well above 30,000 feet in shirtsleeve comfort, without the need for oxygen breathing systems. The advent of the XC-35 marked the emergence of the practical pressurized cabin for high-altitude commercial and military aircraft, a milestone event in aerospace history suitably recognized by the award of the Collier Trophy to the XC-35 team in 1938.

In 1937, the Air Corps bought three Lockheed Electra Model 10-A twin engine aircraft. These planes were designated Y1C-36 and were essentially identical to the civilian version. The three planes were initially used as senior staff transports throughout the mid and late 1930s. One Y1C-36 crashed in 1938, but the remaining two aircraft were used for regular transport and utility missions during the 1940s into the World War II era. In 1938, the Y1C-36s were re-designated C-36 and later UC-36 (Utility Cargo) in 1943. The UC-36s were eventually sold to the Brazilian Air Force and served into the early 1950s.

XC-35 UC-36
Span 55 ft. 0 in. 55 ft. 0 in.
Length 38 ft. 7 in. 38 ft. 7 in.
Height 10 ft. 1 in. 10 ft. 1 in.
maximum gross weight 10,500 lbs. 10,300 lbs.
Passenger capacity Three 8
Engines Two Pratt & Whitney XR-1340-43 radials of 550 hp each Two Pratt & Whitney R-985-13 radials of 450 hp. each
Crew Three (pilot, co-pilot and engineer) Two (pilot and co-pilot)
Maximum speed 236 mph 205 mph
Cruising speed 214 mph 190 mph
Range 800 miles 810 miles
Service ceiling 31,500 ft. 19,500 ft.



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