Cars compared in wind tunnel

[aerohead]

Originally Posted by NeilBlanchard

Hello,



Right, I understand that. My comment was towards what some posts seem to be saying: that just because a vehicle is taller, means that it must necessarily therefore have a higher drag coefficient.

The OP does list an item saying that "...lowering by 20 mm reduces Cd by 0.01" which implies that this is a linear affect. I can't see how this could be a constant? All else being equal, lowering a vehicle only reduces the frontal area of the tires only.

Both the Boxfish and the Aptera are relatively tall, and they have much lower Cd than almost any other vehicle; so height is only one possible factor in the Cd.

Something that comes to mind when thinking of 'dropping' a car,is the affect on fineness ratio,which Hucho very much associates with low drag potential.
Lowering,essentially 'lengthens' the car and the air likes that.
The new Leaf,and it's sister racer,Nismo Leaf both have "template" rooflines,however the Nismo is remarkably lower,giving it a fineness ratio closer to a high-mpg concept car.Nissan seems to be exploiting the benefit for performance.
This might be a safe general assumption.Many of the highest mpg cars use active suspension to lower the car at speed for even better savings than at static height.