X-22A Variable Stability System

Of all the present crop of VTOL research aircraft, only the X-22A will have a variable stability and control system, designed and constructed as an integral part of the basic airplane. In fact, this is the first time that a new type of aircraft has been planned from the beginning to be a variable stability and control airplane. The variable stability and control capability, in conjunction with the high control power of the basic airplane, will make the X-22A unique and a highly useful and versatile tool for research into the flying qualities of the VTOL class of aircraft. Experience with variable stability airplanes has shown that many engineering test-pilots do not appreciate the effectiveness of the "variable stability" concept until they have flown a variable stability airplane. Since flying qualities research is a highly specialized field and, for the most part, only pilots have observed the variable stability airplane in operation, it seems reasonable to assume that many engineers in the aeronautical field may not appreciate the variable stability concept. Therefore it may be profitable to begin this presentation with a functional definition of a "variable stability airplane", a brief enumeration of its possible uses, advantages and limitations and a description of the general features of mechanization.