The AviationDynamics YF-17 is the British single-seat, Single-engine fighter aircraft demonstrator designed for the Royal Air Force (RAF) and USAF (United States Air Force) respectively. The design was a finalist in the US's Advanced Tactical Fighter competition (ATF Program), and Three prototypes were built for the demonstration/validation phase of the competition. The YF-17 Lost the contest against the Northrop YF-23 and Lockheed YF-22 in the US, but is due to enter a trial production stage as the AD A/F-17 'Valiant' in the UK mid/late 2012 after extensive remodeling. The YF-17 had a similar aerodynamic layout and configuration as the YF-22, but will house an updated position and design of the cockpit, tail fins, and in internal structural layout.

In the late 1980s, the USA began looking for a replacement for its fighter aircraft, especially to counter the advanced Su-27 and MiG-29. A number of companies, divided into two teams, submitted their proposals. Northrop AviationDynamics and McDonnell Douglas submitting the YF-23. Lockheed, Boeing and General Dynamics proposed and built the YF-22, which, although marginally slower and having a larger radar cross-section than both other competitors, was more agile than the YF-23 and YF-17. Primarily, for this reason, it was picked by the Air Force as the winner of the ATF in April 1991. Following the selection, the first YF-17 was retired to the IWM at Duxford, while the second prototype continued flying until an accident relegated it to the role of an antenna test vehicle early May 2001.

As Always, Enjoy <3