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Old 09-17-2010, 02:24 PM   #135 (permalink)
3-Wheeler
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Quote:
Originally Posted by MetroMPG View Post
....regarding your VG question at the transition to ~12 degrees on the underside of the extension: I'd say they may work there. I bet the flow under your car is cleaner than Phil believes it is....
Hi Metro,

It's nice to hear from the inspiration that started my tail extension project!

Right now it's kind of a toss-up between creating a pivoting under tray, or keeping it fixed at the current angle.

The fixed bottom side keeps things allot simpler and makes the structure more rigid and lighter, but causes more air drag due to the steeper angle.

The hinged under-tray can be lower slung for normal driving, and move up and out of the way when encountering ramped inclines. However this design is also weaker in transmitting loads from the tail to the underside mounting blocks, due to the large cutout for the movable piece.

The movable piece can also rattle over bumps as Cd pointed out in an earlier post.

So, for me, simply adding vortex generators would be the preferred approach in this case, if they actually work in this application.

Jim.
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