Proposal to Use Reaction Jets for Variable Stability Airplanes

A totally new concept of control mechanism for a variable stability airplane (VSA) is proposed. The use of cold air jets to generate the required forces and moments when the variable stability systems (VSS) is engaged is envisaged. Feasibility analysis is provided for a medium-transport base airplane, which is conceived as a three-degree-of-freedom VSA platform. A preliminary study was carried out to examine the approximate magnitude of the required thrust that is sought from the reaction jets or thrusters. This Technical Note puts forward two different analytical studies in support of the concept. The first analysis involves matching of stability and control derivatives of the host airplane with that of the other simulated airplanes. The second analysis involves simulation of other dihedral angles. A preliminary feasibility study suggests that air-thruster-based VSS is a viable proposition. However, it also gives rise to a set of design issues that must be addressed comprehensively before commencing any experimentation