Douglas DC-4 Skymaster, Historical Background

The original DC-4 was built in 1938 as a requirement for both United and American Airlines. It began test flying in 1938, but when the U.S. entered into World War 2, the production line was commandeered by the military authorities and thus the first 24 C-54's were produced.
The C-54 and its variants have since seen service with many different Air Forces around the world.
The production line closed in 1947, but many of the military variants found use in civil service.
A total of 1.245 were produced.This number does not include the Canadian built version, as this is not an original Douglas design.

Even while the DC-3 still had to make its first flight, the President of United Airlines, William Patterson, foresaw a need of a larger transport than the DC-3. He convinced his counterparts with American, Eastern, Pan American and TWA to support this project. The original DC-4 was designated DC-4E, E for experimental. This shows how far fetched this dream for a 4-engined transport must have seemed in those days.
Douglas knew hardly what to do with this giant of an airplane... The cockpitcrew consisted of 2 pilots and a flight engineer; they had a seperate external entrance. In the back there was room for 52 passengers in a roomy accommodation. There were lounges with washrooms, a lavatory, a steward's galley, a wardroom and many technical novelties... But Pan American and TWA thought that the DC-4E was too complex and withdrew their support in favor of the smaller Boeing 307 Stratoliner. But Douglas kept faith and after investing nearly half a million man hours in the DC-4E NX18100 (cn1601), it was completed in May 1938.

Click on the photo for a larger image
(c) Eric Birkeland
Photo courtesy © Eric Birkeland.

Mind you, it looked different from the DC-4 shown at my website, as it had a triple tail. The photo on the left illustrates this very well.
Roll-out and test flight occurred on June 7th, 1938 at Clover Field, Santa Monica, California.
The DC-4E received its Certificate of Airworthiness on May 5th, 1939 after many teething problems had been overcome. It was then handed over to United Airlines, who named it 'Super Mainliner' (NC18100). It made many route proving flights and it was reported to be pleasant to handle. However, the complexity of the systems presented excessive maintenance problems and the operating economics were very disappointing, even with the large capacity of 52 passengers.
If you google 'DC-4E flying over Manhatta​n by Margaret Bourke-White for LIFE' you'll get a good picture of the DC-4E.

It was agreed with Douglas to suspend the DC-4E development and aim for a less complex DC-4 project. This led to the C-54 Skymaster and to the DC-4.
The DC-4E was sold and shipped to Japan in 1939. Its fate unclear, faded away in the advent of W.W. II. Later it became clear that it was bought to support Japanese studies into a long-range bomber

The DC-4 was revised, smaller than the DC-4E, lighter and simpler. The wing was altered, the cabin unpressurised, Pratt & Whitney R-2000 Twin Wasps (1.450 hp) were assigned to the case. Eastern, American and United were enthusiastic and Douglas accepted the first commercial orders. Military orders by the USAAF followed (9 C-54s and 62 C-54As with reinforced cabin flooring, special cargo doors and built-in loading hoists).
Then came the Japanese attack on Pearl Harbor and all production facilities were needed for the war effort. The civilian produced Skymasters were impressed in the service, as a stop gap until the actual C-54s were delivered.
There was no prototype DC-4, the first production aircraft cn3050 was completed in Feb. 1942 and was assigned USAAF serial 42-20137. It was first flown March 26th, 1942 at Santa Monica.
At that time the C-54 was the only land-based transport to fly the Atlantic, from New Foundland non-stop to the UK.
To keep up with the orders (during 1942 Douglas had an order of 1.335 C-47s as well to consider, plus numerous others for other types) another factory was built on the site of what is now Chicago O'Hare Airport. Nearly two-thirds of all the C-54s were to be produced here.
A C-54A (cn7470 42-107451) was to become the personal transport for President Roosevelt and specially modified for this role (C-54C). It was named "Sacred Cow". Later President Truman used it extensively and in 1961 it was retired to the Smithsonian Museum.
Santa Monica produced some 100 C-54B transports, but one was special: Winston Churchill was given a private transport as well, a converted C-54B and given RAF serial EW999. It was truely a VIP transport, as it featured electrically-heated toilets seats !
The C-54D was similar to the "B" models, but had improved P&W R-2000-11 engines, delivering 1.350 hp each. A total of 380 were built, more than any other version.
The C-54E retained its cargo door and was able to be quickly converted from cargo- to passenger configuration, seating 50 in canvas bucket seats.
There was no C-54F, instead a C-54B was reconfigured to XC-54F, fitted out with 2 paratroop jump doors. The plan was not pursued.
The C-54G was again with more powerful engines, P&W R-2000-9s. It had a troop carrier interior and production was started in 1945. A total of 162 were being produced until "VJ-Day" and were mostly used for the China-Burma-India (CBI) operation. For information on this operation, see on this website: C-46 Historical & Technical Background Information.
After VJ-Day the order for 235 C-54Gs was cancelled and components for these were used by Douglas to produce the post-war civil DC-4-1009.
A large number of various C-54 were transferred by the USAAF to the US Navy and US Marines Corps, receiving R5D- designations.
XC-54K was a test example, fitted with the air-cooled Wright Cyclone engines.
C-54L was another testcase, for a new fuel system.
38 C54Es were stripped to carry coal during the Berlin Airlift of 1948/1949 and were designated C-54M.
During the United Nations Korean conflict, 30 C-54Es were modified for medical evacuations and redesignated MC-54M.


With peace settling over the world again, Douglas anticipated a strong demand for the commercial DC-4. It was offered in 2 variants, the DC-4-1009 and the DC-4-1037, both which incorporated many of the improvements carried out on the C-54s. The Douglas DC-4-1009 was purely a passenger transport (offered in 2 versions, for day use and one for night use) and the DC-4-1037 kept the cargodoor of the C-54. Both were offered with P&W R-2000 engines, rated 1.450 hp each. The DC-4-1009 had cabin pressurisation.
But they lost out against the cheaper war-surplus C-54s and only 79 DC-4-1009s were built (all unpressurised). No DC-4-1037s were built.
The first one, cn42904 NC10201 was delivered to Western Airlines on Jan.18th 1946 (apparently this aircraft also played a role in the 1946 movie The Best Years of Our Lives; thanks Cliff & Jon! ).
Production was stopped in 1947. The last one, cn43157 went to South African Airways as ZS-BMH.
Canadair produced a license-built variant of the DC-4: the DC-4M North Star; it was basically a DC-4 airframe with some DC-6 components and British Rolls-Royce Merlin engines. The prototype C54-GM made its maiden flight on 15Jul1946. The Canadair-Douglas licence agreement restricted the sale of North Stars to the United Kingdom and Canada; by the time production ended in 1950, Canadair had produced a respectable total of 70 North Stars. Only 1 North Star survives: former RCAF C-54GM (serial 17515) belongs to the Canada Aviation Museum in Ottawa. More info here.

These 2 images were part of an add campaign in the early-1950s, by KLM in conjunction with SPAR Supermarkets (in the Netherlands).
DC-4 being prepared for departure

the stewardess prepares the service in her galley
The DC-4 saw worldwide use with scheduled and non-scheduled operators. But originally it was intended to be used on the US domestic routes. The DC-3 had to make 3 stops en route from New York to Los Angeles, while the DC-4 needed only one. Thus the westbound trip was reduced from 17hrs40 to 14hrs30...Pan American, KLM, Sabena, Air France, SAS and Swissair used the DC-4 on Trans-Atlantic flights. Pan American pioneered the Trans-Pacific route also with DC-4, so did Australian National Airways. ANA flew on behalf of (Canadian) British Commonwealth Pacific Airlines. Flota Aérea Mercante Argentina (FAMA) introduced the DC-4 on routes from South America to Europe.
While the DC-4 (and DC-4E for all its experimenting) was again a big step ahead for aviation, it was overshadowed by the War. After WW2, the DC-3 was around in bigger numbers and fitted better in the budget of numerous operators. Technology saw the DC-6 around the corner, perfecting the Douglas Commercial series: bigger, faster, better economics. Follow this link for more on the DC-6: info on the DC-6.

Sigurgeir Orri wrote me in Mar.2006: " seems you have not mentioned the first Scandinavian Airline that used the Skymaster. It was Loftleidir Icelandic that bought a Skymaster in 1946 and intended to start using it in August, but the company that was supposed to convert the plane went bankrupt. So the first flight was delayed until June 1947. At that time SAS did not have any 4 engine planes and Icelands neighbours in Scandinavia were envious, especially Denmark, since Iceland cut their relationship with the Danish King in 1944 and became independent. The Danes were so jealous they didn't turn on the landing lights when Hekla (the name of the Skymaster) approached Castrup... The pilots had to wait and follow quickly other planes as they landed !
I'm working on a documentary on Loftleidir. I just wanted to tell you this funny little story."

For the above I borrowed heavily from the following publications:
DC-4 by John and Maureen Woods, by Airline Publications (1980). ISBN 0905117719.
Douglas Propliners DC-1 - DC-7 by Arthur Pearcy, by Airlife (1995). ISBN 185310261X. Recommended reading for all aviation historians.
DC-4, stored and deserted

the North Star

There was also a "Canadian DC-4", he North Star. Jeff Rankin-Lowe, author of "The Aircraft of the Canadian Armed Forces", wrote me the following about this DC-4 variant:
The unpressurized RCAF version, the North Star, also known as the C-54GM, had a DC-4 empennage, rear fuselage, flaps, ailerons, and wing tips; C-54G wing centre-section and outer panels; DC-6 fuselage shortened by 80 inches, and a DC-6 nose section and landing gear.
Trans-Canada Airlines (TCA) ordered twenty DC-4M2s, which it also called North Stars. They differed from the RCAF's aircraft in having their rear cargo doors modified for passenger use, a DC-6 main landing gear. And they were pressurized, otherwise they were built from the same mix of DC-4, C-54, and DC-6 components. (Note that there were new-build components to those designs, as well as the ones bought from Douglas as part of the licenced production deal.)
The RCAF and TCA versions were the Canadair Model CL-2.
TCA borrowed six of the RCAF's aircraft (known as the DC-4M1) pending deliveries of its own, which was easy to arrange since both the RCAF and TCA were owned by the Canadian government.
The BOAC version was known as the Argonaut. They had a higher gross weight and more powerful engines. They were the Canadair Model CL-4, also marketed as the C-4. Canadian Pacific Airlines had the C-4-1 North Star, which was essentially the same as the Argonaut.
The sole C-5 had P&W R-2800 radials instead of Merlins. There were other differences, which IIRC included a slightly different fuselage diameter. It became the RCAF's VIP aircraft.
Total production was 71, including 24 C-54GM/DC-4M1s, 20 DC-4M2s; 22 C-4s and four C-4-1s; and one C-5.

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Last updated 11.11.2006