In order to improve the efficiency of propeller propulsion systems, two existing ideas for mitigation of the kinetic energy losses and the resulting aerodynamic interactions are discussed by means of potential based design methods and time accurate RANS CFD simulations. The first concept, a pusher propeller mounted at the aft fuselage using the principle of boundary layer ingestion, intends to reduce the axial kinetic energy loss. The second concept of swirl recovery vanes behind a wing mounted tractor propeller tries to lessen the rotational kinetic energy loss. A power benefit of 7% is found for the first concept. The additional interaction drag of 11% is the main source for further improvement. For the second concept propulsive efficiency gains of 0:4% in a cruise condition to 2:6% in a high thrust condition are found without wing. The addition of a wing has shown to decrease these gains by the reduced swirl recovery of the wing and design changes to the swirl recovery vanes for this configuration are necessary for further improvement.
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