Behavior of the Bell X-1A Research Airplane During Exploratory Flights at Mach Numbers Near 2.0 and at Extreme Altitudes
Drake, Hubert M. and Stillwell, Wendell H. (1955) Behavior of the Bell X-1A Research Airplane During Exploratory Flights at Mach Numbers Near 2.0 and at Extreme Altitudes. Technical Report NACA RM H55G25, Research Engineering, NASA Dryden Flight Research Center.
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Abstract
A flight program has been conducted by the U.S. Air Force consisting of exploratory flights to determine the Mach number and altitude capabilities of the Bell X-1A research airplane. On two flights of the X-1A airplane, one reaching a Mach number of about 2.44, the other a geometric altitude of about 90,000 feet, lateral stability difficulties were encountered which resulted in uncontrolled rolling motions of the airplane at Mach numbers near 2.0. Analysis indicates that this behavior apparently results from a combination of low directional stability and damping in roll and may be aggravated by high control friction and rocket motor misalignment. The deterioration of directional stability with increasing Mach number can lead to severe longitudinal-lateral coupling at low roll rates. The misalignment of the rocket motor could induce sufficiently high roll velocities to excite these coupled motions. Adequate control of these motions was virtually impossible because of the high control friction. In the absence of rolling, poor lateral behavior might be expected at somewhat higher Mach numbers because wind-tunnel data indicate neutral directional stability at about M = 2.35.
| EPrint Type: | NACA Report |
|---|---|
| Keywords: | X-1A aircraft |
| Subjects: | (01 - 09) Aeronautics: (08) Aircraft Stability And Control NACA Publication Aircraft/Project: X-1 |
| ID Code: | 956 |
| Deposited On: | 13 June 2006 |
| Additional Information: | 26 pages. |
