04.10.1961 odbył się 42. lot X-15 (1-23-39) z Robertem Rushworth'em, który osiągnął wysokość 23770 metrów i prędkość 4553 km/h (4,30 Mach).
Był to pierwszy lot testowy X-15 z usuniętym statecznikiem przednim.
4 octobre
- 1961 : 42ème vol d'un X-15 avec Robert Rushworth qui atteint 23 770 mètres d'altitude et 4 553 km/h
4 October 1961. Test Pilot Robert Rushworth flew the first X-15 test with ventral fin removed on flight 1-23-39.
https://x.com/ron_eisele/status/1841958510176960918By mid 1961 the increasing altitudes of X-15 high altitude flights were requiring increasingly high angles of attack for recovery, and as the angles of attack increased the X-15s became more unstable laterally and directionally. To the point that even with the stability augmentation system at high gain, the planes were marginally controllable. Flight Research Center planner Richard Day and Air Force Flight Test Center planner Robert Hoey suspected that the negative dihedral effect caused by the large lower vertical stabilizer was the main contributor to the instability. A number of flight simulator runs convinced them even more, to the point that they convinced station senior managers that a high altitude flight should be made with the lower part of the ventral fin removed to test their theory. On 4 October 1961 USAF pilot Major Robert A. Rushworth made a flight with lower ventral removed - to Mach 4.3 and 78,000 feet. At low angles of attack the handling qualities were about the same as with the full ventral, but a angles above 8 degrees, lateral/directional stability was improved. This success prompted NASA to run a full set of wind tunnel, tests of the X-15 without lower ventral.
https://ethw.org/First-Hand:The_X-15_Project_-_Flight_Testing_-_Chapter_12_of_the_Experimental_Research_Airplanes_and_the_Sound_Barrier
Wątek: X-15 (Przeczytany 28203 razy)