Variable Stability Systems (VSS) or later known as In-flight simulators are aircraft capable of establishing various stability characteristics by modifying the gains in their control laws. These aircraft serve research, training and evaluation purposes and have been flying for over half a century. The most modern and advanced VSS is the F-16 VISTA currently operated by USAF TPS at Edwards which establishes 5 DOF while its initial design proposal was for 6 DOF (see the very interesting initial design below, which included side-force surfaces on the wings as well as split drag petals on the wing tips).
Today, the availability and “integrability” of the various FCS parts can make a low cost VSS project feasible. Following a request, a preliminary analysis on such a project was conducted determining the required project phases and the basic specifications of each VSS part. This still remains work in progress, however more details cannot be released.