Determination of Longitudinal Stability of the Bell X-1 Airplane from Transient Responses at Mach Numbers up to 1.12 at Lift Coefficients of 0.3 and 0.6

Angle, Ellwyn E. and Holleman, Euclid C. (1950) Determination of Longitudinal Stability of the Bell X-1 Airplane from Transient Responses at Mach Numbers up to 1.12 at Lift Coefficients of 0.3 and 0.6. Technical Report NACA RM L50I06a, Research Engineering, NASA Dryden Flight Research Center.

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Abstract

A number of free-flight transient responses resulting from small stabilizer movements were obtained during flight tests of the Bell X-1 airplane (8-percent-thick wing and 6-percent-thick tail). Responses were analyzed to obtain a measure of the longitudinal stability characteristics of the airplane over the Mach number range from 0.72 to 1.12 at lift coefficients of 0.3 and 0.6. The data presented indicate three significant features: (1) The damping varies greatly with Mach number, maximum damping occurring at Mach numbers of 0.82 and 1.08 and a minimum damping at about 0.93; (2) some uncertainty of damping between Mach numbers of 0.91 to 0.95 appears although good agreement with model tests exists throughout the Mach number range covered; and (3) the static stability of the airplane increases with Mach number to a Mach number of about 0.93 and decreases with further increasing Mach number. Data above a Mach number of 0.90 indicate some lift coefficient effects. Agreement of the full-scale flight data and model data over the Mach number range is good.

EPrint Type:	NACA Report
Keywords:	X-1 aircraft
Subjects:	(01 - 09) Aeronautics: (08) Aircraft Stability And Control NACA Publication Aircraft/Project: X-1
ID Code:	953
Deposited On:	15 June 2006
Additional Information:	23 pages.