3 July 1982 – First flight of The prototype General Dynamics F-16XL, derivative of the F-16 Fighting Falcon, with a cranked arrow delta wing, similar in appearance to the wing planform of the earlier Saab 35 Draken from Sweden, that is over twice the size of that of the standard F-16 wing. 
It was originally conceived as a technology demonstrator, later entered in the United States Air Force’s (USAF) Enhanced Tactical Fighter (ETF) competition but lost to the F-15E Strike Eagle. Several years after the prototypes were shelved, they were turned over to NASA for additional aeronautical research. Both aircraft are currently stored at Edwards AFB.
Source: Wikipedia