Originally Posted by wannaklr
That McLaren outer board is just dead sexy!
Always wondered why the leading edges were so blunt. Figured a knife edge would have less drag.
I am not an aerodynamicist, and would love a simple answer.
Drag is created mostly by the low pressure zone behind the moving object. Its not all that important to have a small knife edge cutting into the air compared to having smooth "laminar" airflow along and behind the car/wings. In other words it needs to be knife edge sharp at the back but round and smooth at the front.
For example: A tractor-trailer doesn't have a lot of drag because of all the large flat surfaces on the front (but it is part of it). Most of the drag comes from the low pressure following the huge flat door in the back with nothing to smooth out the airflow. Compare that to a rain drop which is said to be the most aerodynamic shape because it forms on its own naturally with the shape for the lowest possible amount of drag. It has a large rounded tip that tapers back to a sharp point at the back.