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X-4 #
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%20(8X4).JPG) |
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Photo:
Robert Deering 10/18/2012 National Museum of the USAF Wright-Paterson AFB (FFO) Dayton, Ohio |
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The X-4 was
developed for the study of flight
characteristics of swept wing semi-tailless
aircraft at transonic speeds (about Mach
.85). Northrop built two X-4s. The No. 1
aircraft was first flown by Northrop on Dec.
16, 1948, and the second X-4 made its
initial flight on June 7, 1949. The No. 1
aircraft was grounded after its 10th flight
to provide spare parts for the No. 2
aircraft. Northrop's part of the test
program ended on Feb. 17, 1950, with the
20th flight of the remaining X-4.
Although both aircraft were turned over to the Air Force and then to the National Advisory Committee for Aeronautics in May 1950, only the No. 2 X-4 was used in the joint USAF/NACA program to explore stability problems near the speed of sound. The program ended in September 1953 with the 102nd and last flight of the No. 2 aircraft, after proving that swept wing aircraft without horizontal tails were not suitable for transonic flight. Both aircraft survived the test program without serious incident. The No. 1 X-4 is displayed at the Air Force Academy. The No. 2 aircraft was transferred to the museum shortly after the program ended. It was restored by the Western Museum of Flight, Hawthorne, Calif. |
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