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Old 09-01-2012, 11:35 AM   #457 (permalink)
MPG Militia HMV-25E80+A
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Join Date: Mar 2011
Location: Vermont, USA
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FrankenJetta D - '90 Volkswagen Jetta GL
Boat tails and more mods
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The way I THINK I under stand the rear aero is as follows...

Any way you fill the wake will help reduce drag.
For better/best results the tail needs to start near level and gradually increase toward your final angle of 21/22 degrees, or in your case, start with attached flow on the rear window and build from there. If I were building the tail on your car with the testing you've already done, I'd start where the lowered template leaves the rear window, which will still afford you some visibility out the rear, and follow it to your preplanned ending. This will not strictly follow "template" parameters, but I "think" it will still help a lot.

This post is made by a complete novice in the aero world and should be taken with a grain of salt( with a hint of lime and tequila). YMMV

It is always very amusing how our imagination is put to the test when overcoming reality. Redyaris
Boat tail project
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