A flight investigation has been conducted on a typical high-wing personal-owner airplane to determine the effect of control centering springs on apparent spiral stability. The centering springs were used in both the aileron and rudder control systems to provide both a positive centering action and a means of trimming the airplane.

Flight Testing, Volume II: Stability and Control focuses on the development of adequate flight test techniques for the appraisal of stability and control characteristics and flying qualities of airplanes. This book discusses the flying quality requirements, longitudinal motions, and flight determination of stick-fixed neutral points. The determination of aerodynamic parameters from steady maneuvering, desirable control characteristics in steady flight, and various forms of lateral control surfaces are also elaborated. This publication likewise covers the measurement of maximum lift coefficient, emergency anti-spin devices, and concept of the altitude-Mach number flight envelope. This volume is recommended for design, development or research engineers, test pilots, and instrumentation personnel interested in airplane stability and control.