Quote:
Originally Posted by stevey_frac
Ok, i think i see what your saying, if not how i can construct such a beast. The boat tails that i've seen seem to rise much faster then 2.5 degrees. How does that work for them? My working knowledge of aero appears to be limited.
So, the idea scenario here would be to extend a panel down from the bumper, and have it meet with another panel that was maby affixed to the axle to gentle guide the air up into the wake. Then enclose the sides.
Do you think i would see significant gains from something like this, or is there other lower hanging fruit to go after first? Also: Does this only really get gains if I have a bellypan first, and there is laminar air sitting under there already to be guided? I'm not sure what the rules are for reattaching air.
Thanks again for your time!
-Steve
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With a "fixed" boattail,it may be necessary to violate the rules a bit to allow clearance for driving in the real world of driveways and ramps and such.And also,the "big-boys" may have never tested all the permutations of designs we can come up with.The bottom line for boattails is probably,that whatever is done,the wake area and volume is affected and altered such to produce a net-positive result.------ At Epcot Center,
Orlando,Florida,General Motors has an exhibit including a concept car with movable rear valance.As the car speeds onto the highway,the panel lowers closer to parallel with the roadway ( closer to the 2.5 degrees ) and the raises when slower and more likely to encounter obstacles.---------- Typically,the diffuser works best with a full bellypan ahead of it.At the rear axle it's okay to have an open section to allow for axle travel. All mine do.So you could have spanwise structures ahead of and behind the axle at support the skins,leaving an opening.As for numbers,There are some seminars and mod-data info near the top of the aero forum page where you can see specifics about all kinds of mods.------------- I believe that significant gains only come from rear mods.Nobody is going to take a Saws-All to a late model car,re-work the roofline to accept a $3,000 GTP half-semispherical low drag windshield and true fastback roof,and re-engineer everything associated with that area.