The mystery aircraft in our Fall Issue was the U.S. Air Force's Douglas YC-15 Advanced Medium STOL Transport (AMST) of the mid-1970s. STOL was the abbreviation for short takeoff and landing. When used for an airlifter like this one, the term referred to the ability to deliver supplies to ground combat troops using crude runways close to the front lines.
Dating to 1968, the AMST program initially had the goal of producing a replacement for the C-130 Hercules tactical transport. After proposals from three other aircraft makers were weeded out, the YC-15 became one of two aircraft developed and tested during the AMST program. The other was the Boeing YC-14.
The YC-15 made its first flight on August 26, 1975 (almost a year ahead of the YC-14 on August 9, 1976).
The YC-15 had four engines, while the Boeing version had two. They were 15,500-pound thrust Pratt & Whitney JT8D-209 turbofans. The YC-15 used large double-slotted flaps that extended over 75 percent of the wingspan to enhance STOL capabilities. To save costs, it used a modified DC-8 nose-wheel unit and the DC-10 cockpit as adapted for a two-person crew, with two lower windows for visibility during short-field landings.
Never given a popular name ("Loadmaster" was considered), the YC-15 accommodated 90 percent of all Army combat vehicles, including a 62,000-pound extended-barrel, 8-inch (203 mm) self-propelled howitzer. Vehicles were loaded through rear fuselage doors with built-in ramps. The YC-15 introduced a number of innovative features, such as externally blown flaps, which used double-slotted flaps to direct part of the jet...