Quote:
Originally Posted by Vman455
Cross-sectional area (sometimes called frontal area) is the maximum area of the car as viewed from the front or rear. If you can find a blueprint online or a front photo taken from a couple hundred feet with a telephoto lens, you can run it through photo-editing software and get a pixel count and convert that to square feet or square meters. Or, for a rough estimate multiply the manufacturer's width by height by 0.85. For a '96 Outback, that's 68" x 62" x 0.85, or 24.9 square feet.
For a Kamm tail, you want a nicely tapering extension that terminates in a flat face approximately 50% of the cross-sectional area, or about 12.5 square feet. Wunibald Kamm discovered that lopping the end of a full tail off preserved most of the drag reduction but with reduced length. Here's one of his cars:
A box cavity is a short tail with perpendicular sides, top and/or bottom, inset from the rearmost surfaces of the car. Here's one from a formerly-active member here:
These can reduce drag by anywhere from 2-5% typically, and they're a lot easier to build than a full tail. |
So would it be possible to combine those two concepts? Say instead of rear wheel skirts, I extended them out past the back to taper together, creating a sort of boat tail/box cavity below the rear window?
Edit: ****. That would still leave me needing to redo the electrical array. Hm. Decisions, decisions...