# Basic Aerodynamics

**URL:** <https://forums.speedlife.net/t/basic-aerodynamics/112835>\
**Category:** SON240sx Automotive\
**Created:** [January 31, 2008, 10:50am UTC](https://forums.speedlife.net/t/basic-aerodynamics/112835 "2008-01-31T10:50:38Z")\
**Posts on this page:** 1\
**Showing post:** 11

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**Author:** ![Solarian](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/solarian/32/5514_2.png) [@Solarian](https://forums.speedlife.net/u/Solarian)\
**Post date:** [January 31, 2008, 2:22pm UTC](https://forums.speedlife.net/t/basic-aerodynamics/112835/11 "2008-01-31T14:22:18Z")

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> [@That other guy with red elise...](https://forums.speedlife.net/t/that-other-guy-with-red-elise/15751/9):
>
> LOL i have the problem with the text aswell, the dots are air particled 😛
> 
> Anyways, I DID mean the first picture you drew. Because lets say you have 2 possiblities. One is to have the understray as close to the underbody as possible. Two would be to have a small gap, with a piece cut and sticking down:
> 
> \_\_\_\_\_\_\_\_\_ _…_  
> …/
> 
> Dots = movement of air.
> 
> So when the air is pushed up against the undertray then the pressure is forced down (i.e. down force) once it reached the inside of the undertray.
> 
> This is what I was trying to get across. It’s probably incorrect though.

As per MSN, that flap would create a lot of pressure buildup and make things really messy. There is a better way to do that exact same thing  
\_\_\_\_\_\_\_\_\_/ _…_  
…  
But it would follow both paths. Either way, that’s unnecessary and will perform worse than a classic undertray. You would want it if for some reason you had a mid engine car with a trunk mounted intercooler though 😃

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