Douglas X-3 Stiletto
The Douglas X-3 Stiletto was an experimental aircraft that had been built for the study of aerodynamic effects at speeds of Mach 2 and above. Furthermore, the design with the small " stub wings " and then some new materials such as titanium should be tested.
With the construction of the first X-3 was started back in 1949. Due to the satisfactory results with the Bell X- 1A and the Douglas D- 558- I, their testing at that time was still running, should now be achieved with the Bell X- 2 and the Douglas X-3 speeds up to Mach 3 and tested the flight behavior be. The X-3 should start in a conventional manner and not like the X -1A and X-2 are dropped from a modified Boeing B-29 bomber.
For the acquisition of measuring data, the X -3 was provided with 850 pressure 150 and temperature 185 load measuring points. The fuselage was constructed extremely long and slender, to keep the air resistance to a minimum. This " tip " appearance of the X-3 was ultimately the nickname " Stiletto". Two copies should be built.
Delays the test program led to the fact that the planned Westinghouse J47 jet engines with 2,994 kp thrust were not available and had to be replaced by the much weaker J34 because its dimensions were similar. This compromise the achieved flight performances were significantly impaired. The first flight took place on 20 October 1952. The take-off distance amounted to just under 4000 meters. Since, however, could not be reached the required speeds with the built engines, and the data collected in the subsonic range also were not satisfactory, it was decided to use the unfinished second copy of the X-3 only as a spare part support.
For nothing but the X - 3 program was not: The utility of the short wings, was proved; this construction came in later aircraft in serial production for use, for example, at the Lockheed F- 104. The NACA engineers were able to continue to collect some new insights in the field of aerodynamics. The greatest pioneering effort but was provided by the X- 3 with respect to the tire: Due to the high takeoff and landing speeds important findings were collected, which eventually applied in the production of later flight and even car tires.
From NASA, the last of a total of 51 flights is dated to 23 May 1956.