Quote:
Originally Posted by freebeard
Why, the elevation changes?
Bidirectional passes on 'level' ground would cancel out effects of wind. Multiple downhill passes take twice as long but wouldn't the gravity assist act as a multiplier for the effect your trying to measure? A vehicle that maintains a steady coasting speed will be more aerodynamic than one that loses speed, and less aerodynamic (plus RR) than one that gains speed on the test section.
I've been wrong before.
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The low-load/high-load whammie of up and down elevation throws the engine's BSFC map around so much you'd never know what to attribute to what.MPGs would be all over the place.
With the SAE testing protocol,the only significant variable is a change in drag,so there's no additional noise to filter out of the scatter-plot, to discern that drag signal.