During the early 40's, just after Pearl Harbor, the Army Air Corps realized the need to move their large vehicles and equipment great distances in a short amount of time. The personnel at Douglas Aircraft's Santa Monica division also saw the need and immediately began design studies towards an extended version of the DC-4.
Douglas began development of the C-74 Globemaster I in early 1942. This large four-engine transport would meet the need for an aircraft that could support the demands of a global logistics network with larger payload and transoceanic range. In July 1942, a contract was awarded to Douglas to build 50 of the giant planes. Development took longer than expected, and the first aircraft did not fly until just after the end of the war. By that time the government was canceling or reducing all aircraft production, including the production run of the C-74, which was reduced to just 14 aircraft.
The Douglas C-74 Globemaster was the largest US land plane next to the Douglas XB-19 when it flew for the first time on September 5, 1945. Pan Am called it the "Clipper Type 9". Pan Am twenty-six from Douglas under the designation DC-7in June 1944, but the price kept climbing and the order was cancelled in October 1945. This "DC-7" is totally unrelated to the "DC-7" that emerged in the early 1950s as a stretched longer range development of the DC-6. Even authoritative accounts are confused on this point, with one noting erroneously that " ... the C-124 and commercial DC-7 designs shared common wings, landing gear, engines, and other components, both having been derived from a late World War II design that the Air Force bought as the C-74."
The Globemaster used tricycle landing gear, so the cargo floor was flat. One unusual feature of the C-74 is that the pilot and co-pilot each had their own glass canopy, giving the aircraft the appearance of having two bug eyes. Called Globemaster because of its ability to circumnavigate the world with only two stops, the C-74 was designed for self-sufficiency. A combination of features enabled it to operate anywhere in the world, independent of any transportation network or facilities. Self-contained electrical power enabled the crew to change engines if needed and to load cargo using internal cranes and freight elevators that lifted cargo to and from the ground. Part of the floor would drop down and function as an elevator.
The advantages presented by an autonomous, self-contained cargo loading system are glaring; they give cause to question why such systems have not been integrated into current aircraft. In point of fact, there were earlier cargo aircraft designed with limited enhanced cargo-handling capability. Both the Douglas C-74 and its more widely produced follow-on, the C-124, had an internal elevator system to accommodate the split-level cargo compartment. Each also had a built-in crane to aid in cargo loading. These aircraft were designed in 1942 and 1949.
The C-74 was basically a considerably scaled-up DC-4 / C-54, with a low wing, four engines, conventional tail, and tricycle landing gear with twin wheels on each unit. The engines were Pratt & Whitney (P&W;) R-4360-27 Wasp Major radials with 3,000 horsepower each, driving fully reversible Curtiss electric propellers to permit shorter landings and improved taxi maneuverability. The wings features a sophisticated arrangement of flaps to permit shorter takeoffs.
The C-74 had a crew of five, including copilot, pilot, radio operator, navigator, and flight engineer. Crew rest quarters were included for long-duration missions. A toilet, buffet and sleeping quarters were also provided for a relief crew. Passageways were provided in the wing to permit the flight engineer to perform servicing and repairs while the machine was in flight.
In an aerodynamic sense, the airplane was remarkably efficient. The C-74 featured a laminar-flow wing and full-span fowler flaps. One of its strangest features was the twin bubble canopies. The aircraft had unusual 'bug-eye' canopies which were chosen more for safety than aerodynamics. They allowed the pilots a nearly unobstructed 360-degree view around the aircraft. The separate canopies made communication and cooperation between the pilot and co-pilot difficult; a conventional cockpit would later be retrofitted. The crew was provided with quarters, though compact. The engineer's station was behind the copilot, the radio operator was stationed behind the pilot and the navigator was stationed behind him. As this scheme also complicated interactions between the two men, it was later changed to a more conventional cockpit arrangement. Which aircraft had the bug-eye cockpit scheme and which did not; when it was implemented; and whether the conventional cockpit scheme was retrofitted to early aircraft is unclear.
Only one C-74 was used during the Berlin Airlift, with a capacity of 74,000 pounds. The C-74's performance in the Berlin Airlift had a significant impact on subsequent airlift operations. A single C-74 reached Rhein-Main Air Base on 14 August 1948 for service tests, and made its first trip to Berlin on the 17th with twenty tons of flour. Prior to its return to the United States on September 21, the C-74 delivered 445.6 tons of cargo in twenty-five trips for an average of 17.82 tons per trip, proving itself as superior to the C-54 as the C-54 was to the C-47. Above all, its great size gave it the capability of delivering bulky industrial and construction equipment. It had a 22-ton payload, but its heavy weight broke up the runways at Tempelhof Air Base, Berlin.
In the push for a large, strategic transport designed especially for military use, the tests of the Douglas C-74 provided an opportunity and a gamble. If the aircraft failed to meet expectations, it could compromise efforts to purchase big military transports. The C-74 proved its effectiveness, especially on September 18 when it flew six round-trips into Berlin and delivered 114.4 tons of cargo.
As the Berlin Airlift continued, Air Force staff increasingly recognized the need for a military transport capable of carrying a twenty-five-ton cargo. Such an airplane would do the work of three C-54s and would reduce most of the problems of scheduling, maintenance and report, the number of crews and maintenance personnel with all of the attendant housing, feeding, and administrative problems, by a third. It promised huge economies of scale. Sixty-eight C-74s could do the work of 178 C-54s or 899 C-47s. It would only have to fly 5,400 trips per month to the C-54's 13,800 or the C-47's 39,706. The C-74 would require 180 aircrews to do the same amount of flying as 465 for a C-54 operation or 1,765 on a C-47 operation. Only 2,700 maintenance personnel would required compared to 4,674 for the C-54 or 10,588 for the C-47. All would be accomplished using only 6,804,000 gallons of gasoline compared to 8,577,600 for the C-54s and 14,294,00 for the C-47s. At the height of the airlift, the CALTF was flying out of nine fields and delivering to three. With a fleet of Douglas C-74s, the airlift could have delivered 8,000 tons of cargo daily operating out of two bases and delivering to only one. With additional bases and two in Berlin, Tunner believed that he could deliver over 24,000 tons of cargo. And all of this could be done at a substantially reduced cost.
All the C-74s were stationed at Brookley Air Force Base, Ala., in 1950. By then, the Douglas C-124 "Globemaster II," the vastly improved successor of the C-74, was already on its way. All C-74 Globemasters were retired from active duty with the Air Force by July 1955. The Air Force had scrapped all the C-74s at Davis-Monthan AFB, Arizona in 1965. The Air Force Museum scrapped the last vestige of Air Force Globemaster Is when they relegated the YC-124C, 48-795 (the prototype of the Globemaster II which had been converted from C-74, 42-65406) to fire-fighting training in 1969.
During its short career set a record for being the first aircraft to cross the North Atlantic with more than 100 passengers, and was flown at a gross weight of 86 tons - the most weight for any powered aircraft up to that time. The fifth Globemaster had the distinction of being the prototype for the plane that would replace the C-74: the C-124 Globemaster II.