The YC-14 STOL Prototype: Its Design, Development, and Flight Test

The YC-14 was an experimental aircraft developed between 1971 and 1977 by the Boeing Company and sponsored by the U.S. Air Force. Its basic mission was to carry large, bulky payloads into and out of short, rough dirt fields 2000 ft long, even if an engine failed. Designed to replace the C-130, it had considerably more capability with a large fuselage designed to carry the largest tanks, trucks, and vans in use. The YC-14 configuration had a high wing and large T-tail with the flow from the 50,000 lb thrust turbofan engines exhausted over the top of the wing and passing over the upper surface of the flaps. The flow was turned by the flaps and deflected to augment the aerodynamic lift of the configuration. It was the most efficient powered-lift system ever developed. This case study takes you step by step through the request for proposal process, the trade study and configuration development, detailed design and construction, and ground and flight tests. The effects of politics, management, and personalities on the project are also addressed.