The C-123 Provider was an American military transport aircraft designed by Chase Aircraft and subsequently built by Fairchild Aircraft for the United States Air Force. In addition to its USAF service, which included later service with the Air Force Reserve and Air National Guard, it also went on to serve most notably with the United States Coast Guard and various air forces in South East Asia. The C-123 Provider was designed originally as an assault glider aircraft for the United States Air Force (USAF) by Chase Aircraft as the XCG-20 (Chase designation MS-8 Avitruc). Two powered variants of the XCG-20 were developed during the early 1950s, as the XC-123 and XC-123A. The only difference between the two was the engine. The XC-123 used two Pratt & Whitney R-2800-CB-15 air-cooled radial piston engines, while the XC-123A used two General Electric J47-GE-11 turbojets, the same as those on the Boeing B-47 Stratojet. It was initially well regarded for tactical troop transport for its ruggedness and reliability and ability to operate from short and unimproved airstrips, which meant the low slung turbojets, prone to ingesting foreign objects, were dropped in favor of the more conventional option. The XC-123A had its engines replaced with R-2800s and was redesignated YC-123D.