The Design and Integration of a Distributed Fan Propulsion System within a Split-Wing

A baseline propulsion system has been designed as a starting point in a previous SBIR effort for this project which consists of two turboshaft engines, a generator coupled directly (no gearbox) with each engine, and electric cables to motors that drive shrouded fans installed in or over the wing. For this baseline, there are eight fans per wing, and the turboshaft engines use kerosene fuel as the energy source. One major issue faced by this type of configuration is the propulsion integration of not only the structure with motors in a split wing, but also the aerodynamics of such a configuration. In the previous study, high pressure recovery inlets, exhaust nozzle area control, thrust vectoring and variable pitch fans were considered, along with the initial layout of the entire structural integration. The work proposed here aims to further address these concerns and outline a potential fan, inlet and nozzle design methodology for split-wing distributed propulsion. This methodology can be turned into a design tool, for which the framework will be created as part of this study to be fully completed in a possible Phase II. In addition, and most important to this topic, several aerodynamic aircraft concepts have also been looked at under currently supported work with California Polytechnic State University on their N+2 NRA contract to study future CESTOL aircraft and during internal study efforts at ESAero. The work proposed here will complement much of that work by taking a better look at some novel integration arrangements in the configurations. This will specifically address overall vehicle efficiency by looking at the aerodynamic concepts inherently designed into the aircraft. This will be an important part of the study, as a properly integrated distributed propulsion system will offer the means to reduce "specific" fuel consumption, thereby increasing aircraft operating efficiencies to reduce overall mission fuel burn.