Terry,
It is my understanding that where the panel is located is where the down force is, because that is where the venturi is located. The back of the car is after the venturi and separate in its function. That being drag or more down force. So its angle has to be considered and it is added or subtracted to the venturi. I think that is why the backs of the 40 are shaped like they are, an upside down wing. Just my opinion.
If you want to see some interesting images of the principle(s), go here:
https://www.google.com/search?q=ber...wfk-ZTUDg&sqi=2&ved=0CE8QsAQ&biw=1280&bih=668
Bill
It is my understanding that where the panel is located is where the down force is, because that is where the venturi is located. The back of the car is after the venturi and separate in its function. That being drag or more down force. So its angle has to be considered and it is added or subtracted to the venturi. I think that is why the backs of the 40 are shaped like they are, an upside down wing. Just my opinion.
If you want to see some interesting images of the principle(s), go here:
https://www.google.com/search?q=ber...wfk-ZTUDg&sqi=2&ved=0CE8QsAQ&biw=1280&bih=668
Bill