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Douglas DC-3

Airliner and military transport aircraft family

  • 16 min read
  • 7 chapters
This is a picture of a Working Life Museums in Sweden, number
Towpilot · CC BY-SA 3.0

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Through Airline, World War II and United Airlines

The DC-3 had many exceptional qualities compared to previous aircraft. It was fast, had a good range, was more reliable, and carried passengers in greater comfort. Before World War II, it pioneered many air travel routes. It was able to cross the continental United States from New York to Los Angeles in 18 hours, with only three stops. It is one of the first airliners that could profitably carry only passengers without relying on mail subsidies. In 1939, at the peak of its dominance in the airliner market, around 90% of airline flights on the planet were by a DC-3 or one of its variants.

Following the war, the airliner market was flooded with surplus transport aircraft, and the DC-3 was no longer competitive because it was smaller and slower than aircraft built during the war. It was made obsolete on main routes by more advanced types such as the Douglas DC-4 and Convair 240, but the design proved adaptable and was still useful on less commercially demanding routes.

Civilian DC-3 production ended in 1943 at 607 aircraft. Military versions, including the C-47 Skytrain (the Dakota in British RAF service), and Soviet- and Japanese-built versions, brought total production to over 16,000. Many continued to be used in a variety of niche roles; 2,000 DC-3s and military derivatives were estimated to be still flying in 2013; by 2017 more than 300 were still flying. As of 2023, it was estimated about 150 were still flying.

Design and development

"DC" stands for Douglas Commercial. The DC-3 was the culmination of a development effort that began after an inquiry from Transcontinental and Western Airlines (TWA) to Donald Douglas. TWA's rival in transcontinental air service, United Airlines, was starting service with the Boeing 247, and Boeing refused to sell any 247s to other airlines until United's order for 60 aircraft had been filled. TWA asked Douglas to design and build an aircraft that would allow TWA to compete with United. Douglas' design, the 1933 DC-1, was promising, and led to the DC-2 in 1934. The DC-2 was a success, but with room for improvement.

The DC-3 resulted from a marathon telephone call from American Airlines CEO C. R. Smith to Donald Douglas, when Smith persuaded a reluctant Douglas to design a sleeper aircraft based on the DC-2 to replace American's Curtiss Condor II biplanes. The DC-2's cabin was 66 inches (1.7 m) wide, too narrow for side-by-side berths. Douglas agreed to go ahead with development only after Smith informed him of American's intention to purchase 20 aircraft. The new aircraft was engineered by a team led by chief engineer Arthur E. Raymond over the next two years, and the prototype Douglas Sleeper Transport (DST) first flew on December 17, 1935 (the 32nd anniversary of the Wright Brothers' flight at Kitty Hawk) with Douglas chief test pilot Carl Cover at the controls. Its cabin was 92 in (2,300 mm) wide, and a version with 21 seats instead of the 14–16 sleeping berths of the DST was given the designation DC-3. No prototype was built, and the first DC-3 built followed seven DSTs off the production line for delivery to American Airlines.

The DC-3 and DST popularized air travel in the United States. Eastbound transcontinental flights could cross the U.S. in about 15 hours with three refueling stops, while westbound trips against the wind took 17+1⁄2 hours. A few years earlier, such a trip entailed short hops in slower and shorter-range aircraft during the day, coupled with train travel overnight.

Several radial engines were offered for the DC-3. Early-production civilian aircraft used either the 9-cylinder Wright R-1820 Cyclone 9 or the 14-cylinder Pratt & Whitney R-1830 Twin Wasp, but the Twin Wasp was chosen for most military versions and was also used by most DC-3s converted from military service. Five DC-3S Super DC-3s with Pratt & Whitney R-2000 Twin Wasps were built in the late 1940s, three of which entered airline service.

Production

Total production including all military variants was 16,079. More than 400 remained in commercial service in 1998. Production was:

  • 607 civilian variants
  • 10,048 military C-47 and C-53 derivatives built at Santa Monica, California, Long Beach, California, and Oklahoma City
  • 4,937 built under license in the Soviet Union (1939–1950) as the Lisunov Li-2 (NATO reporting name: Cab)
  • 487 Mitsubishi Kinsei-engined aircraft built by Showa and Nakajima in Japan (1939–1945), as the L2D Type 0 transport (Allied codename Tabby)

Production of DSTs ended in mid-1941 and civilian DC-3 production ended in early 1943, although dozens of the DSTs and DC-3s ordered by airlines that were produced between 1941 and 1943 were pressed into the US military service while still on the production line. Military versions were produced until the end of the war in 1945. A larger, more powerful Super DC-3 was launched in 1949 to positive reviews. The civilian market was flooded with second-hand C-47s, many of which were converted to passenger and cargo versions. Only five Super DC-3s were built, and three of them were delivered for commercial use. The prototype Super DC-3 served the US Navy with the designation YC-129 alongside 100 R4Ds that had been upgraded to the Super DC-3 specifications.

Turboprop conversions

From the early 1950s, some DC-3s were modified to use Rolls-Royce Dart engines, as in the Conroy Turbo Three. Other conversions featured Armstrong Siddeley Mamba or Pratt & Whitney PT6A turbines.

The Greenwich Aircraft Corp DC-3-TP is a conversion with an extended fuselage and with Pratt & Whitney Canada PT6A-65AR or PT6A-67R engines fitted.

The Basler BT-67 is a conversion of the DC-3/C-47. Basler refurbishes C-47s and DC-3s at Oshkosh, Wisconsin, fitting them with Pratt & Whitney Canada PT6A-67R turboprop engines, lengthening the fuselage by 40 in (1,000 mm) with a fuselage plug ahead of the wing, and some local strengthening of the airframe.

South Africa-based Braddick Specialised Air Services International (commonly referred to as BSAS International) has also performed Pratt & Whitney PT6 turboprop conversions, having performed modifications on over 50 DC-3/C-47s / 65ARTP / 67RTP / 67FTPs.

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