Progress in optimising the propulsive fuselage aircraft concept
As a promising approach towards synergistic propulsion-airframe integration, Bauhaus Luftfahrt has continued its analysis of the propulsive fuselage concept (PFC). The PFC utilises boundary-layer ingestion realised by an aft-installed fan in order to facilitate wake filling, thereby significantly reducing the required propulsive power demand. In the studied configuration, the PFC, targeting an entry-into-service year of 2035, features a fuselage fan primarily serving the purpose of wake filling, while two advanced wing-podded turbofans deliver any residual thrust.
Building upon methods developed as part of the DisPURSAL project1 (see 2014 Yearbook), aircraft-integrated design studies were conducted. Figure 1 shows, for example, the implications of varying fuselage fan intake duct heights. The operating empty weight (OEW) increases monotonically due to the installation of the additional fuselage power plant, while the block fuel characteristic results from the combined impact of propulsion system integration and aircraft aerodynamics. Having selected a best-and-balanced design, fuel savings of 9.2 %, compared to an equally advanced conventional reference aircraft, are obtained. The maximum take-off weight (MTOW) characteristic is not significantly increased over the conventional reference. As an alternative to the mechanical fuselage fan drive train, initial investigations on a turbo-electric layout with power off-takes from the under-wing podded engines were conducted (Fig. 2). Such a solution could simplify the aero-structural integration of the fuselage fan, while potentially allowing for an even higher benefit in vehicular efficiency.
1The project DisPURSAL received funding from the European Union’s 7th Framework Programme under grant agreement no. 323013.