Douglas DC-6

Douglas DC-6 of Swiss airline Balair in 1976

Type Airliner/transport aircraft Manufacturer Douglas Aircraft Company Maiden flight15 February 1946 Introduced March 1947Status 49 fully active Produced 1946-1959 Number built >700 Developed from Douglas DC-4Variants Douglas DC-7

The Douglas DC-6 is a piston-powered airliner and transport aircraft built by the Douglas Aircraft Company from 1946 to 1959. 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 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.

1 Design and development
2 Variants
3 Operators
- 3.1 Civil operators
- 3.2 Military operators
4 Survivors
5 Specifications (DC-6B)
6 See also
7 References
8 External links

Design and development

The United States Army Air Forces commissioned the DC-6 project as the XC-112 in 1944. The Air Force wanted an expanded, pressurized version of the popular C-54 Skymaster transport with improved engines. By the time the XC-112 flew, the war was over, and the USAAF had rescinded its requirement.

Douglas converted its prototype into a civil transport (redesignated YC-112A, having significant differences from subsequent production DC-6 aircraft) and delivered the first production DC-6 in March of 1947. However, a series of mysterious in-flight fires (including the fatal crash of United Airlines Flight 608) grounded the DC-6 fleet later that year. The cause was found to be a fuel vent located adjacent to the cabin cooling turbine intake. All DC-6's in service were modified to correct the problem, and the fleet was flying again after just four months on the ground.

Pan Am used DC-6 aircraft to inaugurate its first trans-Atlantic tourist class flights, starting in 1952.

On February 12, 1955 a Sabena DC6 crashed on mount Terminillo, near Rieti, Italy. 29 people died, including 1953 Miss Italia winner Marcella Mariani. Later that same year, on November 1, a time bomb exploded aboard United Airlines Flight 629, a DC-6, killing 44 people above Longmont, Colorado.

The USAF had C-118 Liftmasters in service from 1957 through 1975.

Douglas designed four basic variants of the DC-6: the "basic DC-6," and higher-gross-weight, longer range versions—the "DC-6A" had a large cargo door and was designed for cargo work, while the "DC-6B" was designed for passenger work and the "DC-6C" was a "convertible" aircraft that could accommodate both. The military version, essentially similar to the DC-6A, was the C-118. The DC-6B, powered by Pratt & Whitney R-2800-CB-17 engines with Hamilton Standard 43E60 constant speed reversing propellers, was regarded by many to be the ultimate piston-engine airliner from the standpoint of ruggedness, reliability, economical operation, and handling qualities.

The military renewed its interest in the DC-6 during the Korean War, and commissioned a number of aircraft that later found their way into civilian service. Harry Truman's first presidential aircraft was an Air Force VC-118 called The Independence.

In the 1960s, two DC-6's were used as transmitter platforms for educational television, based at Purdue University, in a program called MPATI (Midwest Program for Airborne Television Instruction)[1].

Many older DC-6 aircraft were replaced by the Douglas DC-7: those that survived into the Jet Age were replaced by Boeing 707 and Douglas DC-8 aircraft.

2006 marked the 60th anniversary since the introduction of the DC-6.

Variants

XC-112: United States military designation of an improved version of the C-54 became the prototype DC-6.
DC-6: Main production variant
DC-6A: Fitted with cargo door.
DC-6B: Passenger only variant
DC-6C: Convertible cargo/passenger variant.
VC-118: One DC-6 bought as a presidential transport with special 25 seat interior and 12 beds.
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 re-designated.
VC-118B: R6D-1Zs re-designated.
R6D-1: United States Navy designation for the DC-6A, 65 built.
R6D-1Z: Four R6D-1s converted as staff transports.

Operators

Main article: Douglas DC-6 operators

G-APSA displaying at Hamburg The Red Bull DC-6 landing at Salzburg

About 100 DC-6s still fly (or are potentially capable of flight).
In 2002, 49 were fully active.
One DC-6A, G-APSA, is in use by Air Atlantique, Coventry, UK (see The Six). They also own a DC-6B, G-SIXC.
One is in use by Red Bull in Salzburg, Austria.
One DC-6 is in use by Namibia Commercial Aviation.
An unknown number are in use as freighters or waterbombers in Canada and the western US.

Civil operators

Passengers deplaning an SAS DC-6 An Ardco DC-4 air tanker lands at General William J. Fox Airfield in Lancaster, California

Current operators of the DC-6: Today, most DC-6's in commercial use are based in Alaska. Several other DC-6's are still in operation for small carriers in South America.

United Kingdom
- Air Atlantique, a former cargo carrier based in Coventry, England.

United States
- Air Cargo Express
- Everts Air Fuel
- Northern Air Cargo

Military operators

Harry Truman's C-118, The Independence

Survivors

Several DC-6s are preserved in museums. The most well-known is President Harry S. Truman's Independence, which is preserved at the National Museum of the United States Air Force, Wright-Patterson Air Force Base in Ohio.

Specifications (DC-6B)

Data from Airliners.net[1]

General characteristics

Crew: 3: captain, copilot, flight engineer, plus attendants appropriate to number of passengers
Capacity: 54-102 passengers
Length: 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 ft (135.9 m)
Empty weight: 55,357 lb (25,110 kg)
Max takeoff weight: 107,000 lb (48,500 kg)
Powerplant: 4× Pratt & Whitney R-2800CB17 "Double Wasp" radial engine, 2,500 hp (1,700 kW) with water injection each
Propellers: Hamilton Standard 43E60 "Hydromatic" constant speed props with autofeather and reverse thrust