Multiple Trim Solutions Assessment for a Bio-Inspired Rotating Empennage Fighter Aircraft

Aircraft with nontraditional actuators sometimes have multiple trim solutions for a single flight condition. Such is the case for the bio-inspired rotating empennage fighter aircraft, which has multiple distinct trim solutions most easily differentiated by varying tail rotation angles. In the present work, these trim solutions are evaluated from various perspectives, including minimum drag, dynamic stability, controllability, and control effort. The purpose of the present paper is to evaluate the multiple trim solutions of the BIRE aircraft in order to determine which trim solution is best for a given flight scenario. It is found that, in a steady coordinated turn, the minimum-drag, minimum-throttle solution is the negative tail rotation solution. It is also found that the near-zero tail rotation solution has the least divergence in comparative linearized analysis. Similar findings are observed in steady-heading sideslip trim solutions.