Hybrid powertrain for light aircraft

Abstract

In this paper, we evaluate the possibility of employing a hybrid powertrain to propel a light aircraft. The work suggests that the incorporation of a hybrid powertrain has little effect on fuel consumption for a light aircraft operating in a condition of straight and level cruise. However, there is a potential decrease in fuel consumption when a light aircraft operates either in climb or when manoeuvring over a conventionally powered aircraft. This is due to three main factors, namely, the energy harvested during descent by a windmilling propeller, the engine being switched off during descent and the fact that the air/fuel mixture does not have to be enriched during climbing phases. Estimating the potential fuel savings is obviously mission dependent, however, an unshrouded propeller could harvest enough energy to provide 39% of the excess power required for climbing. This figure could be significantly increased by use of a shrouded propeller.