Douglas DC 6B

While the DC-3's and DC-4's civilian careers were interrupted by WW2, the opposite applies to the DC-6, which started off in response to a military airlift requirement, and went on to become Douglas' most successful four engined piston airliner.

During WW2 the USAAF was impressed with its C54 fleet's long range and payload capabilities and so ordered development of a larger and improved variant. Designated YC112, this long range transport featured more powerful 1565kW (2100hp) R280022W engines and a lengthened fuselage. The development timetable of the YC112 though was such that it did not fly for the first time until February 15 1946, by which time the war ended and the USAAF requirement no longer stood.

Instead Douglas continued development of the type as a long range airliner, resulting in the DC-6. The YC112 served as the prototype for the DC-6 program, and the first civil production aircraft were delivered to US airlines in March 1947. Entry into service however was not smooth with the fleet grounded for four months later that year after two inflight fires, one being fatal, caused by fuel venting entering the cabin heater ram air intake.

Development of the DC-6 into the DC-6A and B also began in 1947. Main changes were a fuselage stretch and more powerful engines. The DC-6A was optimised for freight work, the equivalent passenger version was the DC-6B. The DC-6C was a convertible passenger/freight model. Renewed military interest in the DC-6 was sparked by the Korean War, with the result that large numbers of USAF C118s and USN R6D1s were built. Many of these aircraft later found their way into civil hands.

Powerplants

DC-6 - Four 1340kW (1800hp) Pratt & Whitney Double Wasp R2800CA15 18 cylinder twin row radial piston engines (with a maximum output rating of 1790kW (2400hp) with water injection) driving three blade constant speed Hamilton Standard propellers.
DC-6B - Four 1685kW (2500hp) R2800CB17s.

Performance

DC-6 - Cruising speed 501km/h (270kt).
Initial rate of climb 1070ft/min.
Max range 7376km (3983nm). DC-6B -
Cruising speed 507km/h (274kt).
Service ceiling 25,000ft.
Range with max payload 4835km (2610nm)
range with max fuel 7595km (4100nm).

Weights

DC-6 - Empty 23,840kg (52,567lb),
max takeoff 44,129kg (97,200lb).
DC-6B - Empty 25,110kg (55,357lb),
max takeoff 48,534kg (107,000lb).

Dimensions

DC-6 - Wing span 35.81m (117ft 6in),
length 30.66m (100ft 7in),
height 8.66m (28ft 5in).
Wing area 135.9m2 (1463sq ft).
DC-6B - Same except length 32.18m (105ft 7in), height 8.74m (28ft 8in).

Capacity

DC-6 - Flightcrew of three or four. Passenger accommodation typically for between 48 to 56, but most aircraft now usually equipped to carry freight.
DC-6B - Typical passenger seating for 54, with max seating for 102, but now usually configured for freight.

Production

Total DC-6 production of 665, comprising 174 DC-6s, 73 DC-6As, 288 DC-6Bs, 105 C118s and 25 R6Ds. Approximately 100 remain in service.