EDWARDS AIR FORCE BASE, Calif -- A C-135B Stratolifter flown by a Military Air Transport Service crew, set 10 new world payload records. Maj David W. Craw, during Operation Swift Lift, flew the Stratolifter carrying about 66,000 pounds to an altitude of 47,171feet, breaking the existing record by more than 4,000 feet. During the same flight, the aircraft broke all previous records for payload-to-altitude in the 15,000, 20,000, and 25,000-kg categories. Maj Vernon Hamann then piloted the same airplane and weight for new speed records over the 2,000-kilometer course. Flying at 615.18 mph at 20,000 feet, he also broke speed records for 5,000, 10,000, and 15,000 kg and set new records for 20,000, 25,000, and 30,000 kg.
In the early 1960s, the Military Air Transport Service operated a fleet consisting almost entirely of propeller-driven aircraft such as the piston-powered Douglas C-124 Globemaster II and C-133 Cargomaster turboprop. While capable of carrying large, outsized payloads, they were becoming increasingly obsolescent and lacked the global reach required of the rapidly-modernizing Air Force. In May 1960, Congress approved the purchase of 50 C-135 aircraft; it was selected in part because of its low development cost, being a straightforward derivative of the KC-135 tanker already in production. Ultimately, only 15 C-135As would be produced (in addition to three converted from KC-135s while still on the assembly line), with 30 additional aircraft being delivered as C-135Bs with the improved Pratt & Whitney TF33 turbofan engine. The C-135 was largely intended as an interim measure pending the development of more specialized jet transports such as the Lockheed C-141 Starlifter, and as such it incorporated numerous compromises in its strategic airlift capability. The aircraft's load floor was some 10 feet off the ground, which required ground-handling equipment, its single side-loading cargo door was limited in what could fit through it, and its useful range was approximately 6,000 miles, insufficient to reach many of the Air Force's operating locations in Asia and the Pacific Rim. While range was greatly improved over earlier transports, it could not be augmented by aerial refueling, as C-135s were not configured with refueling receptacles. Additionally, its takeoff and landing performance required long runways available only at the largest military bases or commercial airports, which were not necessarily located in close proximity to potential combat areas. The Lockheed C-141 entered front-line service in April 1965, which finally gave MATS and its successor, Military Airlift Command, the strategic airlift capability it needed. By the early 1970s, the C-135 fleet had been modified and relegated to other duties, which included staff/VIP transport, systems testing, and strategic reconnaissance.