Hybrid configuration – Advanced A.P.U. concept for future turboprop

The paper presents the study of new propulsion and electric system architecture, for a green regional twin turboprop, that can be defined Hybrid Configuration Advanced APU (HCAA). The aircraft propulsion is provided by traditional turboprop engines which are coupled with electrical motor/generator (M/G). The M/G, other than traditional functions of engine starter and electric generator, can also supply power together with the turboprop during take-off. In this way, the turboprop size can be reduced, so during cruise, they run at higher power ratio with reduced consumption. Moreover, the HCAA allows the green taxi (performed without any thermal engine running) by means of M/G fed by batteries or other storage devices. For a further reduction of engine fuel consumption, the power required by aircraft utilities is provided by the M/G driven by APU which is running during flight. Other advantages of the HCAA system configuration are related to safety during take-off, in particular a better unbalanced condition behaviour. The HCAA should be considered as a concept aimed for lower fuel consumption, but it has a weight higher than traditional configurations one. This underlines the importance to proceed to further studies for preliminary partial application other than about weight reduction.