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Old 08-31-2011, 09:37 PM   #35 (permalink)
autogyro
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Oh, good grief! I suppose everybody on this thread has a hobby horse to ride, so I'll saddle up too.
At least in my copy of Hucho (chapter 4) he mentions that there are other basic body shapes that surpass the Klemperer/Gottingen shape form the 20's, specifically the Morelli shape from 1976. (I actually have the paper)
That's not my point. A big part of chapter 4 is "detail optimization". This is where the rubber meets the road, literally. Drag caused by wheel turbulence is a huge factor, and has only recently begun to be modeled and tested with any sophistication. Trailing wheel vortices from the rear wheels alone can consume 5kW. (Morelli again)
Likewise cooling system drag.
Hucho's answer, and mine, is to test, and test again, using reasonably sized (30%) models to get reasonable Reynolds numbers. My belief is that you don't need the MIRA wind tunnel to do this.
Automotive body engineering - Roof Rack "Wind Tunnel": A Naive Idea?
Sure, play with all the basic Shapes you want, but the devil is in the Detail Optimization.
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