Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Idea for cars with un-aerodynamic windshields

Cd · 06-12-2011, 10:03 PM

If I understand your idea correctly, you are thinking of adding a small airfoil shape to the top of the roof of the car to direct the flow in the correct direction ?

We have discussed something similar here : http://ecomodder.com/forum/showthrea...-suv-8918.html

If there is concern that you have flow separation at the top of the windshield, you could always just round off the edges. It doesn't take much of a rounded edge to keep flow attached.

You could then tuft test to see if there is indeed a problem still.

I remember reading a comment from one of the guys that worked on the EV-1 aerodynamics. He stated in a magazine article published in HotRod Magazine
( i think this is it here : Bonneville National Motorsport Event - Hot Rod )

He stated that one of the aero myths out there is that you need a steeply sloped windshield to get good aero. I think 45* degrees was quoted as the angle at which airflow becomes affected.

06-12-2011, 10:03 PM	#3 (permalink)
Cd Ultimate Fail Join Date: Feb 2008 Location: Austin,Texas Posts: 3,585 Thanks: 2,872 Thanked 1,121 Times in 679 Posts	If I understand your idea correctly, you are thinking of adding a small airfoil shape to the top of the roof of the car to direct the flow in the correct direction ? We have discussed something similar here : http://ecomodder.com/forum/showthrea...-suv-8918.html If there is concern that you have flow separation at the top of the windshield, you could always just round off the edges. It doesn't take much of a rounded edge to keep flow attached. You could then tuft test to see if there is indeed a problem still. I remember reading a comment from one of the guys that worked on the EV-1 aerodynamics. He stated in a magazine article published in HotRod Magazine ( i think this is it here : Bonneville National Motorsport Event - Hot Rod ) He stated that one of the aero myths out there is that you need a steeply sloped windshield to get good aero. I think 45* degrees was quoted as the angle at which airflow becomes affected.