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Old 01-25-2008, 12:20 AM   #55 (permalink)
Fuzzy
EcoModding Lurker
 
Join Date: Jan 2008
Location: NoVA
Posts: 27

Spin - '03 Mazda Miata SE
90 day: 26.55 mpg (US)
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Quote:
Originally Posted by diesel_john View Post
http://www.pagendarm.de/trapp/progra...les/NACA4.html
this site has an interactive program which changes the shape of the airfoils.
<meh> the NACA 4-digit series equations can be found floating around the internet (or Theory of Wing Sections).


Quote:
Originally Posted by diesel_john View Post
I moved the sliders until i got a shape that i could fit a large rectangle inside of. then downloaded the x&y coordinates and multiple both columns by the same number to the size of a truck in feet without going over legal road width.
John, I'd be interested to see what you decided on. Could you PM the coordinates to me?

Quote:
Originally Posted by diesel_john View Post
don't know the effects of my assumption on drag. I do see where the flow is going to stay against the surface a lot longer at slower speed. what do you think about the above site. the attachment in post # 46 would be the top view with the rectangle vehicle inside. along the bottom i would have a splitter all the way around. the sides would come straight up a couple feet with this profile then just rotate the curve over the vehicle like a jump rope to form the top. the biggest drag may be the joint effect at the ground, and lots of wetted area but if I am staring with a Cd of 0.02 or such wild number how could it not be extremely low, until the engine and driver overheat of course.
This sounds similar to the Nissan Goodwood 'Gravity Racer' (linkage)or whatever from a couple years ago. It is important to send most of the flow around the car instead of over, since that will limit how much lift you have to compensate for... allowing a more stable vehicle with lower drag.

Last edited by Fuzzy; 01-25-2008 at 09:16 AM.. Reason: added (linkage)
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