Quote:
Originally Posted by Quoth
It might a cube law? 3 times faster needs 27 x more energy?
Even square law would be 9 x more energy at 3x speed.
But the shape of trailer, "tractor" and spacing between them acounts for a lot which is why birds fly in a > shape at a particular spacing.
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Air drag for 3x speed requires 9x power and 27x energy for fixed time and 9x energy for fixed distance
At 90mph air drag dwarfs rolling resistance but it is 3x 30mph and increases linearly with total weight, so higher total weight would take more energy even in a vacuum.
mpg also takes a big hit if there is a lot of climbing, even with regenerative braking, and if you run out of juice before significant descending you don't even get that.