On Feb 18, 8:16*pm, "js.b1" wrote:
On Feb 18, 4:51*pm, harry wrote:

It is as you pass 140mph that drag takes over, bhp required rockets
and mpg begins to collapse.

The main form of drag varies as the square of speed. There is no magic
number at which it suddenly happens.

What? I do not imply that there is...

At 99mph only 64 bhp is needed - hence mpg is 32.
At 140mph drag is SO much higher that bhp required rockets and mpg
begins to collapse.

56mph may only require 8 bhp, with mpg of 58.
100mph however requires 64 bhp, with mpg of 32.
140mph requires over 171 bhp, with mpg of 17.
250mph requires over 1000 bhp, with mpg of 5.

As cars pass a 140mph top speed so bhp rockets & mpg collapses,
including around town (the 1000bhp car for example only delivers 15mpg
on the urban cycle). Aesthetically people are not too keen on a super
low coefficient of drag vehicles, but at some point that will change
as oil company pricing bites.

As you are an idiot,

You are a ****ing moron. Try using batteries instead of PV.

that means if you go twice as fast you get four times the drag.
If you go three times as fast, you get nine times the drag.
http://en.wikipedia.org/wiki/Drag_equation

Drag at 99mph is not particularly high in modern cars, drag past
140mph most certainly is and bhp must rocket to compensate.


There is no "barrier" or sudden jump at 140 mph orany other speed up
to the speed of sound Drag increases progressively.
Only an idiot would think there is.