POSSIBLE HYBRID PROPULSION CONFIGURATION FOR TRANSPORT JET AIRCRAFT

This contribution is aimed to study the possible advantages of installing, for a hybrid propulsion aircraft, electric motors and related propellers into dedicated supplementary nacelles. This innovative solution is different if compared with the configuration, already studied for a regional turboprop (Chiesa et al. 2013), in which the electric motors are in the same nacelles of the internal combustion engines. As it has been expected, it offers the advantages of avoiding mechanical links between the two units and, more relevant, the possibility to be applied to jet aircraft too. In fact, the main contribution of electric motors is expected during ground operations, at take-off and descent phases (i.e. at low speed), so the propellers can be useful to integrate or even substitute the jet engines. At high speed, the propellers, of course, is configured in order to reduce drag. Considering the design of a new airliner concept, a preliminary design study is necessary to optimize the location of supplementary nacelles. For the nacelles configuration, which holds only the electrical motor, can also be considered a retractable installation as for RAT (Ram Air Turbine). Please note that in hybrid propulsion context, RAT function can be clearly demanded to electric motor, with the advantages of optimizing drag at high speed, taking into account installation problems.