Douglas DC-6

DC-6
A Douglas DC-6B of Western Airlines, c. 1952
Role Airliner/transport aircraft
Manufacturer Douglas Aircraft Company
First flight February 15, 1946
Introduction March 1947 with American Airlines and United Airlines
Status Out of production, active service
Primary users Pan American World Airways
Northwest Orient Airlines
Capital Airlines
Delta Air Lines
Produced 1946 - 1958
Number built 704
Developed from Douglas DC-4
Developed into Douglas DC-7

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 prototype Douglas XC-112A which first flew on 15 February 1946, converted to DC-6 standard in 1956 and flown by TASSA of Spain from 1963 until 1965

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 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 By the time the prototype XC-112A flew on 15 February 1946 the war was over, the USAAF had rescinded its requirement, and the aircraft was converted to YC-112A, being sold in 1955.[1]

Douglas Aircraft modified the design into a civil transport 80 in (200 cm) longer than the DC-4. The civil DC-6 first flew on 29 June 1946, being retained by Douglas for testing. The first airline deliveries were to American Airlines and United Airlines on 24 November 1946.[1] 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.

Operational history

Passengers alighting from an SAS DC-6: Note the upper row of windows, indicating this was built as the optional sleeper variant of the original-length DC-6
Sabena DC-6B arriving at Manchester in 1955 after a nonstop scheduled passenger flight from New York
Universal newsreel about the DC-6

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 (49,000 kg), with CB-17 engines rated at 2,500 hp (1,900 kW) 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 (60 in (150 cm)) higher-gross-weight, longer-range versions—the DC-6A with cargo doors forward and aft of the wing on the left 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.[2]

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.[3] 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.[4]

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.[5]

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 the Boeing 707 and Douglas DC-8.

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.[6] Prices for the DC-6A in 1957–58 were £460,000–£480,000. By 1960, used prices were around £296,000.[6] Equivalent prices for the DC-6B in 1958 were around £500,000. Used prices in 1960 were around £227,000.[6]

From 1977 to 1990 five yellow-painted Douglas DC-6Bs were used as water bombers in France by the Sécurité Civile. They were registered F-ZBAC, F-ZBAD, F-ZBAE, F-ZBAP, and F-ZBBU.[7]

Variants

Original length DC-6 of KLM at Manchester Airport in 1953
UAL DC-6 at Stapleton Airport, Denver, in September 1966
Pan Am DC-6B at London Heathrow in September 1954 on a transatlantic tourist flight
XC-112A
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
DC-6
Initial production variant produced in two versions.
DC-6-1156 a 53- to 68-seat domestic variant with 2,400 hp (1,800 kW) 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 (17,870 l), increased takeoff weight to 97,200 lb (44,100 kg) and 2,400 hp (1,800 kW) R-2800-CB16 engines.
DC-6A
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 (1,800 kg) lift elevator and a Jeep. The Jeep was a public relations stunt and shortly after, dropped.[8]
DC-6B
All-passenger variant of DC-6A, without cargo door.
DC-6B-1198A a 60- to 89-seat domestic variant with 2,400 hp (1,800 kW) R-2800-CB16 engines
DC-6B-1225A a 42- to 89-seat trans-ocean variant with increased fuel capacity to 5,512 US gal (20,870 l), increased take off weight to 107,000 lb (49,000 kg) and 2,500 hp (1,900 kW) R-2800-CB17 engines.
DC-6B-ST
Swing tail freighter conversion to the DC-6B done by Sabena. Two converted, only one still flies owned by Buffalo Airways [9]
DC-6C
Convertible cargo/passenger variant.
VC-118
United States military designation for one DC-6 bought as a presidential transport with special 25-seat interior and 12 beds.[10]
C-118A
Designation of DC-6As for the United States Air Force, 101 built.
VC-118A
C-118As converted as staff transports.
C-118B
R6D-1s redesignated.
VC-118B
R6D-1Zs redesignated.
R6D-1
United States Navy designation for the DC-6A, 65 built.
R6D-1Z
Four R6D-1s converted as staff transports.

Operators

G-APSA in British Eagle scheme
G-APSA displaying at Hamburg
The Red Bull DC-6B landing at Salzburg
A DC-6B N7919C belonged to Reeve Aleutian Airways in 1972

Current operators

Today, most DC-6s are inactive, stored, or preserved in museums. A number are still flying in northern bush operations in Alaska and Canada, while several are based in Europe and a few are still in operation for small carriers in South America.

Former operators

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

Survivors

Harry Truman's VC-118, The Independence

As of 2014, 147 DC-6s survived, of which 47 were airworthy; several were preserved in museums.

Specifications

Comparison of models[20][21]
Variant DC-6 DC-6A DC-6B
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,
2,400 hp (1,800 kW) with
water injection each 		Pratt & Whitney R-2800-CB16
"Double Wasp" radial engine,
2,400 hp (1,800 kW) with
water injection each 		Pratt & Whitney R-2800-CB17
"Double Wasp" radial engine,
2,500 hp (1,900 kW) with
water injection 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 gal (16,100 l)
4,722 US gal (17,870 l) 		up to 5,512 US gal (20,870 l)
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)

See also

Related development
Aircraft of comparable role, configuration and era
Related lists

References

Notes

  1. 1 2 Roach & Eastwood, 2007, p. 273.
  2. ↑ Winchester 2004, pp. 130–131.
  3. ↑ Winchester 2004, p. 131.
  4. ↑ "Boeing History: DC-6/C-118A Liftmaster Transport." Boeing.com. Retrieved: October 3, 2011.
  5. ↑ "Purdue University." ait.net. Retrieved: October 17, 2010.
  6. 1 2 3 "Douglas: DC-6." Flight, 18 November 1960, pp. 799–800. Retrieved: 27 October 2012.
  7. ↑ (French)http://www.netpompiers.fr/index.php?id=48
  8. ↑ "Jeep and Elevator Fly With Lifmaster." Popular Mechanics, February 1950, p. 111.
  9. ↑ "Douglas DC-6." Century Of Flight, 2003.
  10. ↑ DOUGLAS VC-118A LIFTMASTER
  11. ↑ http://www.thedc6.com/
  12. ↑ "Douglas DC-6B." The Douglas DC-6 Association of South Africa. Retrieved: September 13, 2011.
  13. ↑ "Factsheets: Douglas VC-118 'Independence'." National Museum of the United States Air Force, June 19, 2006. Retrieved: January 26, 2012.
  14. ↑ "Aircraft by Name: Liftmaster." . Retrieved: January 30, 2015.
  15. ↑ "The Flying Bulls - DC-6B History." flyingbulls.at.Retrieved: September 13, 2011.
  16. ↑ "Outdoor Exhibits - C-118A “Liftmaster”" National Jimmy Doolittle Air & Space Museum, Retrieved: September 20, 2013.
  17. ↑ "Airmen Restore Aircraft Used by Elvis Presley." elvis.com, June 22, 2011. Retrieved: August 18, 2011.
  18. ↑ "DC-6 Diner." airbasecoventry.com. Retrieved: November 23, 2011.
  19. ↑ Lozano, Esteban. "VOLANDO SOBRE EL ESPACIO AEREO DE CLO". http://spottingcali.blogspot.com. Retrieved 17 October 2014. External link in |website= (help)
  20. ↑ "The Douglas DC-6." airliners.net. Retrieved: March 20, 2006.
  21. ↑ "Douglas DC-6A." American Museum Of Aviation. Retrieved: September 13, 2011.

Bibliography

  • 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.

External links

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