U.S. Air Force Fact Sheet NORTHROP-MCDONNELL DOUGLAS YF-23     Northrop-McDonnell Douglas YF-23. (U.S. Air Force photo) Northrop-McDonnell Douglas YF-23. (U.S. Air Force photo) Top view of the Northrop-McDonnell Douglas YF-23 in flight. (U.S. Air Force photo) Northrop-McDonnell Douglas YF-23 in flight. (U.S. Air Force photo) Northrop-McDonnell Douglas YF-23 in-flight refueling. (U.S. Air Force photo) Northrop-McDonnell Douglas YF-23 in flight. (U.S. Air Force photo) Both YF-23s in flight. (U.S. Air Force photo) The two Northrop-McDonnell Douglas YF-23 prototypes in flight. The aircraft on display at the National Museum of the United States Air Force is the darker one on the right. (U.S. Air Force photo) In 1981 the USAF developed a requirement for an Advanced Tactical Fighter as a new air superiority fighter. It would take advantage of the new technologies in fighter design on the horizon including composite materials, lightweight alloys, advanced flight control systems, higher power propulsion systems and stealth technology. Air Force leaders believed these new technologies would make aircraft like the F-15 and F-16 obsolete by the early 21st century. In 1985 the Air Force sent out technical requests for proposals to a number of aircraft manufacturing teams. Like the YF-22 team, the Northrop team built two YF-23 prototypes, one with General Electric YF-120 engines and the other with Pratt & Whitney YF-119 engines. After extensive flight testing the YF-22 was selected for production.  The museum has a YF-23A on display in its Research & Development/Flight Test Gallery. Type Number built/ converted Remarks YF-23 2 ATF; lost to YF-22 TECHNICAL NOTES: Engines: Two Pratt & Whitney F119-PW-100s of approx. 35,000 lbs. thrust each (with afterburner) or two General Electric F120-GE-100 turbofans; engine competition won by Pratt & Whitney Maximum speed: Approx. Mach 2.0 Service Ceiling: Approx. 65,000 ft. (ATF design spec) Span: 43 ft. 7 in. Length: 67 ft. 5 in. Height: 13 ft. 11 in. Weight: 54,000 lbs. takeoff (YF-23/ATF design spec) Crew: One Click here to return to the Fighter Aircraft index.