# 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:** 9

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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, 1:46pm UTC](https://forums.speedlife.net/t/basic-aerodynamics/112835/9 "2008-01-31T13:46:25Z")

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> [@S&R Petition](https://forums.speedlife.net/t/s-r-petition/15721/49):
>
> Would a higher ‘angle of attack’ decrease your top speed? And at what speeds does this become crucial?

Additional aero always reduces your top speed. It creates two distinct forms of drag, skin friction drag, due to added surface area, and induced drag, which is drag due to lift, or in this case downforce. The effect gets more pronounced with more downforce, there really is not set number. It’s like asking if fat people in your car make it slower, and how fast can I go before I have to make them diet.

> [@S&R Petition](https://forums.speedlife.net/t/s-r-petition/15721/49):
>
> Also, when designing front and rear diffusers and wings, do the angle of attack need to be identical, or greater in the front due to high speed lift?

The front diffuser isn’t really a diffuser per se, it’s just a splitter, so it’s at a zero or close to zero angle of attack. The diffuser in the rear is meant to channel the air out at an angle of attack, while the front splitter just builds a bit of extra pressure. In open wheel motor sports, balancing is a bit easier, because they can just run a front wing, but in regular kinda cars, the splitter will have to make do.

> [@S&R Petition](https://forums.speedlife.net/t/s-r-petition/15721/49):
>
> Another thing, would making a slotted or vented undertray be effective at all? Soemthing like this:
> 
> * * *
> 
> ```
> /
> 
> ```
> 
> Sorry for the primitive drawing. I’ve always been intrigued by the physics behind aero, and I really enjoy physics aswell 🙂
> 
> Thanks Ant!

Not sure what you mean by that drawing… if you’re looking at the car from the side, and it’s like

F \_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_ R  
… /  
Then you sure as hell don’t want anyting like that  
if however you’re looking at it from the front or back, and it’s like  
L\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_R  
…|…|  
then you do want those, because they help channel more of the flow through the middle, so it doesn’t get disturbed by all the stuff coming from the sides.

Edit: dots have been added to put stuff in it’s correct place, otherwise forum moves it to the front

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