Abstract
A new approach to enhance the performance of hybrid fuel-electric aircraft is investigated. This approach adopts Fuel-first strategy (FFS) to increase the effectiveness of electrical propulsion. To illustrate the effectiveness of this method, it is compared to other propulsion types. The FFS is based on starting the electric propulsion only after the aircraft reaches the lowest weight. That is, when fuel is fully consumed. This involves inflight switching of propulsion type, where the first part of the flight is powered by fuel only and the second part is fully-electric. A hybrid version of Piper Cherokee is used to demonstrate the new concept. Modified versions of Breguet equation and Payne range strategy are used to calculate aircraft performance. Adopting FFS resulted in 10.3% fuel saving relative to conventional propulsion as well 4.2% fuel saving relative to parallel hybrid propulsion. The main theme behind this proposal is that by consuming the fuel first, the aircraft becomes lighter sooner, and this enables the batteries to power the aircraft for longer range. Upon comparing the method with other methods in the literature, it was found superior in terms of fuel consumption and performance.