|   | 
  
    
      | Douglas X-3 Stiletto |  
      | The slender, jet-powered X-3, 
      built by Douglas Aircraft Company, Long Beach, California, tested such new 
      materials as titanium and collected data on stability and control, 
      pressure distribution, and flight loads. Because it was underpowered with 
      an interim J34 engine, the X-3 failed to achieve the high speeds for which 
      it was designed, but it pioneered in the use of titanium and contributed 
      to the development of aircraft tire technology.  Following completion of contractor testing in 1953 and 
      a brief Air Force evaluation in 1953-54, the lone X-3 aircraft (serial 
      number 49-2892) was transferred to the National Advisory Committee for 
      Aeronautics, with research pilot Joseph A. Walker of the High-Speed Flight 
      Station (later: Dryden Flight Research Center) flying all 20 of its NACA 
      research flights from 1954 to 1956. During Walker's tenth flight on October 27, 1954, 
      he performed two abrupt, rudder-fixed aileron rolls at speeds of Mach 0.92 
      and 1.05 (0.92 and 1.05 times the speed of sound) that led to inertial 
      roll coupling, causing him to diverge from the expected flight path. These 
      two maneuvers, from which he fortunately was able to recover, yielded a 
      wealth of valuable data on the (as yet not fully understood) phenomenon of 
      inertial coupling. Together with data from other aircraft, such as the X-2 
      and the F-100, this helped the aeronautics community understand how to 
      deal with the phenomenon of coupling dynamics.
 |  
      |   |  
      |  |  |