Tail Area Reduction for Aircraft with Spanwise Distributed Electric Propulsion

Spanwise arrays of electrically driven propulsors may enable significant reductions to the required vertical tail area of an aircraft. The relationship between traditional empennage design and the driving requirements detailed in 14 CFR Part 25 was mapped, and the opportunities in which spanwise distributed electric propulsion could influence the empennage design were identified. The design of the electric microgrid that transmits and controls the flow of power to the propulsors was found to play a critical role in evaluating the potential merits of those opportunities. Careful design of the microgrid architecture was found to relax the asymmetric thrust design condition for the vertical tail to a point of irrelevance. Furthermore, active control of differential thrust between the propulsors could provide dynamic yaw stability to the aircraft, allowing the entire vertical tail to be removed. In contrast, however, a lighter weight microgrid architecture designed with no reconfigurability could exacerbate the asymmetric thrust and require a larger-than-nominal vertical tail. This paper explores the above opportunities and their associated costs as applied to the ECO-150 vision vehicle.