The Douglas C-124 Globemaster II was the main USAF heavy strategic cargo transport during the 1950s and 1960s, until it was replaced by the Lockheed C-5.
The C-124 was developed from the earlier C-74 Globemaster I, a four engined long range transport aircraft that had been developed during the Second World War, but that didn't enter production in time to take part in the war. Only a handful of C-74s were ever built, but the aircraft was a significant improvement on the fleet of twin engined wartime transports.
As a result the USAF asked Douglas to use it as the basis for a more powerful cargo aircraft. The fifth production aircraft was used as the basis for the prototype, which retained the wings, tail and 3,500 Pratt & Whitney Wasp major R-4360-49 engines used on that aircraft and matched them to a new fuselage. The new fuselage had a rectangular cross section and two decks. The upper deck was for passengers, the lower deck for cargo. The most impressive feature of the new aircraft were the clamshell doors in the nose, which opened up to reveal a double ramp that allowed vehicles to be driven straight into the cargo bay. There was also a built in cargo lift just behind the wings, as featured on the C-74.
The double deck configuration was very flexible. It could be used to carry heavy equipment in the cargo bay and the associated personnel in the top deck, or if both decks were used for passengers could take 200 fully equipped troops or 123 stretcher patients, 45 ambulatory patients and 15 medical attendants. It could carry up to 74,000lb of payload. This was an increase of around 50% over the C-74, which could carry 125 troops or 48,150lb of cargo.
The YC-124 was followed by a production prototype and then the first batch of twenty eight C-124As. These were very similar to the prototype when first built, apart from the use of the R-4360-20WA engine, although this provided the same 3,500hp power as the engines used in the prototypes. Eventually 153 C-124As were built. Most were given APS-42 weather radar, carried in a radome in the nose and combustion heaters in pods on the wingtips, which provided heat for the cabin and to deice the wing and tails surfaces.
The C-124A entered service with the Military Air Transport Service and the Troop Carrier Command, just as American entered the Korean War. Soon after entering service its reputation was threatened by two serious accidents, each of which was the worse air disaster in history when it happened. On 20 December 1950 a C-124A crashed during take off from Moses Lake, Washington, with the loss of 86 men. On 18 June 1951 a C-124A crashed near Tokyo, with the loss of all 129 men onboard. However after that the aircraft gained a reputation for reliability and safety.
The YKC-124B was a turbo-prop powered version of the aircraft, designed to be used as a tanker. It was powered by four 5,550 eshp Pratt & Whitney YT34P-1- turbines, which were expected to make it more suitable for use as an in-flight refuelling aircraft. However the USAF decided to use the Boeing KC-97 as its main tanker, and so by the time the prototype made its maiden flight on 2 February 1954 it had been redesignated as the YC-124B. It was used as an engine test bed for two years and then became a ground trainer for missile loading techniques.
The C-124C was the second main production version, with 243 completed. It was powered by four 3,800hp R-4360-63A engines, and could carry more fuel, allowing it to carry a significant amount of cargo over very long distances.
Both the C-124A and C-124B remained in use throughout the 1950s and 1960s and into the 1970s, and were capable of carrying most pieces of Army equipment over long distances. They helped support the US involvement in Vietnam, as well as serving with the reserve and the Air National Guard. They were also used for disaster relief missions. Most were retired during the 1970s.
Engines: Four Pratt & Whitney Wasp Major R-4360-20WA radial engines
Power: 3,500hp each
Wing span: 173ft 3in
Length: 127ft 2in
Height: 48ft 3in
Loaded weight: 175,000lb
Maximum speed: 298mph at 20,800ft
Cruising speed: 264mph
Service ceiling: 22,050
Normal range: 2,300 miles with 50,000lb cargo
Maximum range: 6,280 miles
Cargo: 200 troops or 123 stretcher patents, 45 ambulatory patients and 15 attendants or 74,000lb cargo
Engines: Four Pratt & Whitney Wasp Major R-4360-63A radial engines
Power: 3,800hp each
Wing span: 174ft 1.5in
Length: 130ft 5in
Height: 48ft 3.5in
Empty weight: 101,165lb
Loaded weight: 185,000lb
Maximum weight: 194,500lb
Maximum speed: 304mph at 20,800ft
Cruising speed: 230 mph
Service ceiling: 21,800ft
Normal range: 4,030 miles with 26,375lb cargo
Maximum range: 6,820 miles