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ChazInMT · 07-04-2011, 02:40 AM

Lotsa good back & forth in this thread, in the end I concluded we were both right, flow separation occurs at 23° no matter the placement of the template, however, in order to achieve low Cd aero dynamics, you need to put the template under the wheels. Just cause the flow is attached, does not make it efficient. My theory is a lift drag is created by a too aggressive drop like your proposed boat tail and my 1st gen aero cap. I think the air needs to "build in under pressure" in the back of the vehicle to avoid a dynamically produced low pressure. Don’t worry about a larger "flat spot", you are much better off following the template.

http://ecomodder.com/forum/showthrea...onds-2104.html

Here is the thread with a lot on the template as well.

http://ecomodder.com/forum/showthrea...rt-c-9287.html

And here's where I get the % data from:

http://ecomodder.com/forum/showthrea...tml#post217655

This thread puts to numbers the fact that if you chop off the tail of the ideal aero shape, you really don’t pay a huge penalty for it until you get to around 20-30%.

Hope this serves as some meat & taters for you, I know that this website over the last year and a half has brought me a long ways towards better understanding this stuff.

07-04-2011, 02:40 AM	#13 (permalink)
ChazInMT Aero Deshi Join Date: Jan 2010 Location: Vero Beach, FL Posts: 1,065 MagMetalCivic - '04 Honda Civic Sedan EX Last 3: 34.25 mpg (US) Thanks: 430 Thanked 668 Times in 357 Posts	Lotsa good back & forth in this thread, in the end I concluded we were both right, flow separation occurs at 23° no matter the placement of the template, however, in order to achieve low Cd aero dynamics, you need to put the template under the wheels. Just cause the flow is attached, does not make it efficient. My theory is a lift drag is created by a too aggressive drop like your proposed boat tail and my 1st gen aero cap. I think the air needs to "build in under pressure" in the back of the vehicle to avoid a dynamically produced low pressure. Don’t worry about a larger "flat spot", you are much better off following the template. http://ecomodder.com/forum/showthrea...onds-2104.html Here is the thread with a lot on the template as well. http://ecomodder.com/forum/showthrea...rt-c-9287.html And here's where I get the % data from: http://ecomodder.com/forum/showthrea...tml#post217655 This thread puts to numbers the fact that if you chop off the tail of the ideal aero shape, you really don’t pay a huge penalty for it until you get to around 20-30%. Hope this serves as some meat & taters for you, I know that this website over the last year and a half has brought me a long ways towards better understanding this stuff.