The C-124 was the primary heavy-lift transport for United States Air Force Military Air Transport Service (MATS) during the 1950s and early 1960s, until the Lockheed C-141 Starlifter entered service. It served in MATS-gained, later Military Airlift Command (MAC)-gained, units of the Air Force Reserve and Air National Guard until 1974. Douglas Aircraft developed the C-124 from 1947 to 1949, from a prototype they created from a World War II–design Douglas C-74 Globemaster, and based on lessons learned during the Berlin Airlift. The aircraft was powered by four large R-4360 piston engines producing 3,800 hp (2,800 kW) each. The C-124's design featured two large clamshell doors and a hydraulically actuated ramp in the nose as well as a cargo elevator under the aft fuselage. The C-124 was capable of carrying 68,500 lb (31,100 kg) of cargo, and the 77 ft (23 m) cargo bay featured two overhead hoists, each capable of lifting 8,000 lb (3,600 kg). As a cargo hauler, it could carry tanks, guns, trucks and other heavy equipment, while in its passenger-carrying role it could carry 200 fully equipped troops on its double decks or 127 litter patients and their attendants. It was the only aircraft of its time capable of transporting fully assembled heavy equipment such as tanks and bulldozers. The C-124 first flew on 27 November 1949, with the C-124A being delivered from May 1950. The C-124C was next, featuring more powerful engines, and an APS-42 weather radar fitted in a "thimble"-like structure on the nose. Wingtip-mounted combustion heaters were added to heat the cabin, and enable wing and tail surface deicing. The C-124As were later equipped with these improvements. For operational history and variant details, click here.