Birds of the Same Tail Feather Configuration Prof. Dipl.-Ing. Rudolf Voit-Nitschmann (emeritus) had a lot to do with designing the 1996 Icare II solar-powered sailplane and the 2011 e-Genius. Icare II set several world records in its 20 years, most under the guidance of pilot Klaus Ohlmann. e-Genius won the award for being the quietest airplane at the Green Flight Challenge held in Santa Rosa, California, and was a close second to Pipistrel’s G4 in passenger miles per gallon (equivalent) energy use. Dipl.-Ing. Voit-Nitschmann was kind enough to explain to your editor how the propeller center came to be at the top of the tail on e-Genius. It’s a similar configuration to that on the Icare II*, and one he had found to provide the greatest undisturbed air to the propeller and the least added friction drag, since only the lower part of the blade crossed in front of the upper part of the vertical fin and rudder. This configuration …