Boeing YC-14

The Boeing Model 953 design for STOL performance was based on the use of a supercritical wing, developed by NASA from the wind-tunnel research of Dr. Richard Whitcomb, which provides highly efficient performance from the wing at high subsonic speeds. To this wing Boeing added an advanced wing upper-surface blowing concept, mounting the twin turbofan engines forward and above the wing so that their efflux was exhausted over the wing (this location also gave the airplane a quieter noise footprint.). With the wing’s leading-edge flaps and Coanda-type trailing-edge flaps extended, the high-speed airflow from the engines tended to cling to the upper surface of the wing/flap system and was thus directed downward to provide powered lift. It was the most efficient powered-lift system ever developed.

The YC-14’s basic mission was to carry large, bulky payloads into and out of short, rough dirt fields that were less than 2,000 feet (610m) long, even if an engine failed. It had a large fuselage to accommodate most tanks, trucks and armored personnel carriers used by the U.S. Army.

The first Boeing YC-14 (#72-1873) took to the skies on 9 August 1976 and soon proved to have admirable performance. Two aircraft were built, the second being tail number 72-1874.

At the completion of testing in the late summer of 1977, the YC-14 prototypes were returned to Boeing for continuing development if the company so wished. Due to budget restrictions, no further government funding for development or procurement was made.


Official DesignationYC-14
Primary RoleSTOL transport (prototype)
National OriginUSA
Original ContractorBoeing
OperatorUnited States Air Force
Wingspan129 feet (39.32m)
Length131 feet, 8 inches (40.15m)
Height at Tail48 feet, 4 inches (14.71m)
EnginesTwo General Electric CF6-50D turbofans
Thrust51,000 pounds (227kN) per engine
Cruise Speed449 mph (723km/h)
Max Speed504 mph (811km/h)
Range3,190 miles (5,134km)
Climb Rate6,350 feet (1,935m) per minute
Service Ceiling45,000 feet (13,716m)
Operating Weight117,500 pounds (53,297kg)
Max Payload (STOL)27,000 pounds (12,247kg) with airfield length less than 1,875 feet (571.5m)
Max Payload81,000 pounds (36,741kg) or 150 troops
Max Takeoff Weight (STOL)170,000 pounds (77,111kg)
Max Takeoff Weight251,000 pounds (113,852kg)
Takeoff/Landing DistancesLess than 2,000 feet (610m)
Basic CrewThree
Date DeployedAugust 1976
ProductionTwo aircraft