Laile Under Panel ventilation

[RayRay88]

Originally Posted by ls1ac

Thank you for the understanding, any added air under the car reduces the down force. (the whole purpose of the splitter under paneling side skirts and rear diffuser)
I will have to go back to the books to find definitive reasons why hot air reduces lift. Somehow just stuck in my mind.

I don't think that's true at all. If anything underbody/ground effect aero is much more efficient and has the ability to generate more downforce than the top of a vehicle. Most advanced splitters have diffusers, beveled edges and even center steps to move as much volume as it possibly can to create a greater negative pressure region and drive the splitter to produce more downforce.

But, I still think this panel is just an overpriced piece of aluminum.

[ls1ac]

I think we are saying the same thing. Down force is both negative pressure under the car and wings or what ever over the car that produce a downward force. I was only talking about adding air under the car thus reducing the negative pressure.
The ground effect cars of the 70s with side skirts that touched the ground demonstrated how very important keeping air out from under the car was.

[RayRay88]

Originally Posted by ls1ac

I think we are saying the same thing. Down force is both negative pressure under the car and wings or what ever over the car that produce a downward force. I was only talking about adding air under the car thus reducing the negative pressure.
The ground effect cars of the 70s with side skirts that touched the ground demonstrated how very important keeping air out from under the car was.

I don't believe we are?

Take a look at these advanced front splitters.
Among other things, they have steps in the center to force more air into the under body of the vehicle. The secondary function is to stop the underbody from essentially "stalling" out or being choked of air flow if the front splitter bottoms out.

Side skirts are used to reduce the amount of high pressure area on the side of the car from being sucked in under the car from the sides. Air flow under the car is at a low pressure, which causes the higher-pressure air on the outside and on the sides of the car to come rushing in diminishing ground effect and downforce. Basically they keep the low pressure region under the car "tunneled" and controlled until it can be effectively and smoothly evacuated from the rear diffuser.




Maybe we understand the same principal, but saying air dams and skirts are for keeping air out from underneath the car is misleading at best and a gross over simplification.

[shiumai]

Originally Posted by Tcoat

Love when an old thread get's resurrected and so many want to debate with people that have not been here in 3 or 4 years.

I'm still here! I'm still here! What are we debating?

[ls1ac]

I absolutely agree with grossss simplification. Channeling and bubble effect are a world away from the simple model.


{Wait till we get to trans sonic.}


I still think we are on the same page about the low pressure area under the car. As you said The side skirts are there to keep air from getting under the car. Venting air to the underside is putting more air under the car. That was where I started.

I will also say that a 120MPH car is much more forgiving than a 200MPH car.


I was there when they first found that they had to weld the 160lb man hole covers down.

[extrashaky]

Originally Posted by Tcoat

Love when an old thread get's resurrected and so many want to debate with people that have not been here in 3 or 4 years.

Dammit.

Originally Posted by Tcoat

Let's be real here. At the speeds these car reach, even when track modified, the slight difference in air temperature underneath will have no discernable difference on handling.

It wasn't the folks in this thread who made that claim. Beatrush claims on their product page that the vented cover increases downforce, which seems like bullshit. Laile says it's for cooling, Beatrush says it's for downforce, and I think it's just to waste some money on something nobody really needs.

But it is an interesting discussion of aerodynamics:

Originally Posted by RayRay88

Take a look at these advanced front splitters.
Among other things, they have steps in the center to force more air into the under body of the vehicle. The secondary function is to stop the underbody from essentially "stalling" out or being choked of air flow if the front splitter bottoms out.

This is a good point. An airfoil or wing must have laminar flow over both the top and bottom surfaces for lift (or downforce) to happen. If you cut off the airflow under the car completely, seems like you'd get reduced downforce (or none at all) because the system wouldn't reconnect on the other end.