|Douglas DC-6B of Swiss airline Balair in 1976|
|Manufacturer||Douglas Aircraft Company|
|First flight||February 15, 1946|
|Status||Out of production, in limited use|
|Primary users||Pan American World Airways
Northwest Orient Airlines
Delta Air Lines
|Produced||1946 - 1958|
|Developed from||Douglas DC-4|
The Douglas DC-6 is a piston-powered airliner and transport aircraft built by the Douglas Aircraft Company from 1946 to 1958. Originally intended as a military transport near the end of World War II, it was reworked after the war to compete with the Lockheed Constellation in the long-range commercial transport market. More than 700 were built and many still fly today in cargo, military and wildfire control roles.
The DC-6 was known as the C-118 Liftmaster in United States Air Force service and as the R6D in United States Navy service prior to 1962, after which all U.S. Navy variants were also designated as the C-118.
Design and development
The United States Army Air Forces commissioned the DC-6 project as the XC-112 in 1944. The Army Air Forces wanted a lengthened, pressurized version of the popular DC-4-based C-54 Skymaster transport with more powerful engines. By the time the prototype XC-112A flew on 15 February 1946, the war was over, the USAAF had rescinded its production requirement for the transport, and the aircraft was converted to YC-112A, being sold in 1955.
Douglas Aircraft modified the design into a civil transport, and the civilian DC-6 first flew on 29 June 1946, being retained by Douglas for testing. The first airline deliveries were made to American Airlines and United Airlines on 24 November 1946. A series of inflight fires (including the fatal crash of United Airlines Flight 608) grounded the DC-6 fleet in 1947. The cause was found to be a fuel vent next to the cabin cooling turbine intake; all DC-6s were modified and the fleet was flying again after four months on the ground.
In April 1949, United, American, Delta, National, and Braniff were flying DC-6s in the United States. United flew them to Hawaii, Braniff flew them to Rio de Janeiro, and Panagra flew Miami-Buenos Aires; KLM, SAS, and Sabena flew DC-6s across the Atlantic. BCPA DC-6s flew Sydney to Vancouver, and Philippine flew Manila to London and Manila to San Francisco.
Pan Am used DC-6Bs to start transatlantic tourist-class flights in 1952. These were the first DC-6Bs that could gross 107,000 lb, with CB-17 engines rated at 2,500 hp on 108/135 octane fuel. Several European airlines followed with their own transatlantic services. The DC-6A/B/C subtypes could perhaps fly nonstop from the eastern US to Europe, but needed to refuel in Newfoundland (and perhaps elsewhere) when westbound against the wind.
Douglas designed four variants of the DC-6: the basic DC-6, and the longer-fuselage, higher-gross-weight, longer-range versions—the DC-6A with cargo doors forward and aft of the wing on the port (left hand side) with a cargo floor; the DC-6B for passenger work, with passenger doors only and a lighter floor; and the DC-6C convertible, with the two cargo doors and removable passenger seats.
The DC-6B, originally powered by Double Wasp engines with Hamilton Standard 43E60 constant-speed reversing propellers, was regarded as the ultimate piston-engine airliner from the standpoint of ruggedness, reliability, economical operation, and handling qualities.
The military version, similar to the DC-6A, was the USAF C-118 Liftmaster; the USN R6D version used the more powerful R-2800-CB-17 engines. These were later used on the commercial DC-6B to allow international flights. The R6D Navy version (in the late 1950s and early 1960s) had Curtiss Electric constant-speed reversing propellers.
The USAF and USN renewed their interest in the DC-6 during the Korean War, and ordered 167 C-118/R6D aircraft, some of which later found their way to civil airlines. Harry Truman's first presidential aircraft was an Air Force short-fuselage DC-6 which was designated VC-118, and named "The Independence". It is preserved in the National Museum of the United States Air Force at Dayton, Ohio.
Total production of the DC-6 series was 704, including military versions.
In the 1960s, two DC-6s were used as transmitter platforms for educational television, based at Purdue University, in a program called the Midwest Program on Airborne Television Instruction.
Many older DC-6s were replaced in airline passenger service from the mid-1950s by the Douglas DC-7, but the simpler, more economical engines in the DC-6 have meant the type has outlived the DC-7, particularly for cargo operations. DC-6/7s surviving into the jet age were replaced in frontline intercontinental passenger service by Boeing 707 and Douglas DC-8 aircraft.
Basic prices of a new DC-6 in 1946–47 was around £210,000–£230,000 and had risen to £310,000 by 1951. By 1960, used prices were around £175,000 per aircraft. Prices for the DC-6A in 1957–58 were £460,000–£480,000. By 1960, used prices were around £296,000. Equivalent prices for the DC-6B in 1958 were around £500,000. Used prices in 1960 were around £227,000.
- United States military designation of an improved version of the C-54 (DC-4); became the prototype DC-6. Eventually designated YC-112A, pressurized, P&W R-2800-83AM3 engines
- Initial production variant produced in two versions.
- DC-6-1156 a 53- to 68-seat domestic variant with 2,400 hp R-2800-CA15 engines
- DC-6-1159 a 48- to 64-seat trans-ocean variant with extra crew, increased fuel capacity to 4,722 US Gallons, increased takeoff weight to 97,200 lbs and 2,400 hp R-2800-CB16 engines.
- Freighter variant; fuselage slightly lengthened from DC-6; fitted with cargo door; some retained cabin windows, others had windows deleted. Originally called "Liftmaster" as USAF models. The rear cargo door came standard with a built in 4,000 lb lift elevator and a Jeep. The Jeep was a public relations stunt and shortly after, dropped.
- All-passenger variant of DC-6A, without cargo door.
- DC-6B-1198A a 60- to 89-seat domestic variant with 2,400 hp R-2800-CB16 engines
- DC-6B-1225A a 42- to 89-seat trans-ocean variant with increased fuel capacity to 5,512 US Gallons, increased take off weight to 107,000 lbs and 2,500 hp R-2800-CB17 engines.
- Swing tail freighter conversion to the DC-6B done by Sabena. Two converted, only one still flies owned by Buffalo Airways 
- Convertible cargo/passenger variant.
- United States military designation for one DC-6 bought as a presidential transport with special 25-seat interior and 12 beds.
- Designation of DC-6As for the United States Air Force, 101 built.
- C-118As converted as staff transports.
- R6D-1s re-designated.
- R6D-1Zs re-designated.
- United States Navy designation for the DC-6A, 65 built.
- Four R6D-1s converted as staff transports.
Today, most DC-6s are inactive, stored, or preserved in museums; although a number are still flying in northern bush operations in Alaska and Canada, while several are based in Europe and a few other DC-6s are still in operation for small carriers in South America.
- One DC-6B-ST is in use by Buffalo Airways and based in Yellowknife, Canada.
- One DC-6A, G-APSA, is based in the UK and available for private charter.
- One DC-6B is in use by Red Bull in Salzburg, Austria.
- One DC-6B V5-NCG "Bateleur" is in use with Namibia Commercial Aviation. This was the last DC-6 off the Douglas production line and the last DC-6 in the world in passenger configuration still flying commercially.
- As of 2010[update], several are in use as freighters or waterbombers in Canada. They are no longer used as retardant bombers in the western United States.
- As of 2011, Everts Air Cargo operates eight DC-6s and two C-46s.
A great number of airlines and air forces from several countries included the DC-6 in their fleets at some point in time; these are further detailed in the list of Douglas DC-6 operators.
Accidents and incidents
As of 2014[update], 147 DC-6s survived, of which 47 were airworthy; several were preserved in museums.
- Perhaps the best-known is President Harry S. Truman's VC-118 Independence (s/n 46-505), which is preserved at the National Museum of the United States Air Force, at Wright-Patterson Air Force Base in Dayton, Ohio. The aircraft is on display in the Museum's Presidential Hangar.
- A DC-6B currently owned by Red Bull was once the private luxury transport of Yugoslav President Josip Broz Tito.
- As of March 2010, there was a C-118 in the "bone yard" of MCAS Cherry Point, North Carolina. This was at one time the official aircraft of the Commandant of the Marine Corps. The aircraft was often left open to the weather, and deteriorated considerably. The interior is damaged, but the airframe is largely intact.
- The Navy's second R6D, Bureau Number ("BuNo") 128424, was converted along with six other 128XXX-series Buno R6Ds to VC executive transport configuration. BuNo 128424 was delivered to VR-21, NAS Barbers Point in February 1955, and remained in service until October 1, 1983. It was used as a flag transport for the Commander, U.S. Pacific Fleet. BuNo 128424 is now at the National Museum of Naval Aviation at NAS Pensacola, Florida.
- A C-118A is in the collection of the Jimmy Doolittle Air & Space Museum, located at Travis Air Force Base in Fairfield, California. This aircraft served first in the US Air Force (s/n 51-17651), and was later transferred to the US Navy (BuNo131602).
- A DC-6B ZS-MUL #45329 named Empress of Suva is preserved on a smallholding at Wallmanstahl, north of Pretoria South Africa. This aircraft was stored at Swartkop Air Force Base for over ten years. After two years of restoration by enthusiasts, it was ferried to Wallmanstahl, where a temporary runway had to be constructed.
- A restored USAF C-118 Liftmaster is located at Joint Base McGuire-Dix-Lakehurst, New Jersey. Elvis Presley returned to the United States in this aircraft after serving in the US Army in Germany. as of October 2009[update] it was being restored.
- DC-6B G-SIXC, built in September 1958, spent most of its life in Southeast Asia, and now resides at Coventry Airport, England. After serving with the CIA and Royal Air Lao, it was bought by Air Atlantique Group in 1987. Its last commercial flight was on October 26, 2004. It featured in the 2006 James Bond film Casino Royale. No longer flying, it was converted into a static restaurant at Coventry airport, the "DC-6 Diner".
|Crew||Three to Four|
|Capacity||48-68 Passengers||28,188 lb (12,786 kg) of Cargo||42-89 Passengers|
|Length||100 ft 7 in (30.66 m)||105 ft 7 in (32.18 m)|
|Wingspan||117 ft 6 in (35.81 m)|
|Height||28 ft 5 in (8.66 m)|
|Wing Area||1,463 sq ft (135.9 m2)|
|Empty weight||52,567 lb (23,844 kg)||45,862 lb (20,803 kg)||55,357 lb (25,110 kg)|
|Max takeoff weight||97,200 lb (44,100 kg)||107,200 lb (48,600 kg)||107,000 lb (49,000 kg)|
|Powerplant (4x)||Pratt & Whitney R-2800-CA15
"Double Wasp" radial engine,
1,800 hp (1,300 kW) with
water injection each
|Pratt & Whitney R-2800-CB16
"Double Wasp" radial engine,
2,400 hp (1,800 kW) each
|Pratt & Whitney R-2800-CB17
"Double Wasp" radial engine,
2,500 hp (1,900 kW) each
|Propellers||Hamilton Standard 43E60 "Hydromatic" constant-speed props with autofeather and reverse thrust|
|Cruise speed||311 mph (501 km/h)||315 mph (507 km/h)|
|Fuel Capacity||4,260 US gallons (16,125 litres)
4,722 US gallons (17,874 litres)
|up to 5,512 US gallons (20,865 litres)|
|Range||3,983 nmi (7,377 km)||2,948 nmi (5,460 km) Max payload
4,317 nmi (7,995 km) Max fuel
|2,610 nmi (4,830 km) Max payload
4,100 nmi (7,600 km) Max fuel
|Service ceiling||21,900 ft (6,700 m)||25,000 ft (7,600 m)|
|Rate of climb||1,070 ft/min (330 m/min)|
A note of interest is that the diagram depicts the sleeper version of the early short fuselage DC-6. The very small windows above the standard ones permitted passengers in their Pullman-style bunks a view of the outside.
- Related development
- Aircraft of comparable role, configuration and era
- Handley Page Hermes
- Lockheed Constellation
- Lockheed L-049 Constellation
- Lockheed L-1049 Super Constellation
- Lockheed L-1649A Starliner
- Boeing 377
- Related lists
- List of military aircraft of the United States
- List of military aircraft of the United States (naval)
- Roach & Eastwood, 2007, p. 273.
- Winchester 2004, pp. 130–131.
- Winchester 2004, p. 131.
- "Boeing History: DC-6/C-118A Liftmaster Transport." Boeing.com. Retrieved: October 3, 2011.
- "Purdue University." ait.net. Retrieved: October 17, 2010.
- "Douglas: DC-6." Flight, 18 November 1960, pp. 799–800. Retrieved: 27 October 2012.
- "Jeep and Elevator Fly With Lifmaster." Popular Mechanics, February 1950, p. 111.
- "Douglas DC-6." Century Of Flight, 2003.
- "Douglas DC-6B." The Douglas DC-6 Association of South Africa. Retrieved: September 13, 2011.
- "Factsheets: Douglas VC-118 'Independence'." National Museum of the United States Air Force, June 19, 2006. Retrieved: January 26, 2012.
- "The Flying Bulls - DC-6B History." flyingbulls.at.Retrieved: September 13, 2011.
- "Outdoor Exhibits - C-118A “Liftmaster”" National Jimmy Doolittle Air & Space Museum, Retrieved: September 20, 2013.
- "Airmen Restore Aircraft Used by Elvis Presley." elvis.com, June 22, 2011. Retrieved: August 18, 2011.
- "DC-6 Diner." airbasecoventry.com. Retrieved: November 23, 2011.
- "The Douglas DC-6." airliners.net. Retrieved: March 20, 2006.
- "Douglas DC-6A." American Museum Of Aviation. Retrieved: September 13, 2011.
- Pearcy, Arthur. Douglas Propliners: DC-1–DC-7. Shrewsbury, UK: Airlife Publishing, 1995. ISBN 1-85310-261-X.
- Roach, J and Eastwood A.B., Piston Engined Airliner Production List, 2007, The Aviation Hobby Shop
- United States Air Force Museum Guidebook. Wright-Patterson AFB, Ohio; Air Force Museum Foundation, 1975.
- Whittle, John A. The Douglas DC-6 and DC-7 Series. Tonbridge, Kent, UK: Air Britain (Historians) Ltd., 1971.
- Winchester, Jim, ed. "Douglas DC-6". Civil Aircraft (The Aviation Factfile). London: Grange Books plc, 2004. ISBN 1-84013-642-1.
- Yenne, Bill. McDonnell Douglas: A Tale of Two Giants. Greenwich, Connecticut: Bison Books, 1985. ISBN 0-517-44287-6.
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