The drag _force_ on your vehicle goes up as the square of velocity. F is
proportional to V x V
You go twice the speed, the drag force on your car increases by a
factor of four.
The _power_ (horsepower) requirement due to drag goes up as the cube of
velocity. HP is proportional to V x V x V
You go twice as fast, the HP required goes up by a factor of eight.
The _energy_ required for a fixed distance goes up as the square of
velocity.
You go twice as fast you use four times the energy. -> At 40 mph
you have a range of 80 miles, but at 80 mph your range is only 40 miles.
Bill D.
On 5/17/2021 8:16 AM, Robert Bruninga via EV wrote:
CUBE per Speed:
In my case, (Major east coast pipeline outage), the concern
was with energy used on a trip proportional to cube of speed.
I was trying to get my wife to slow down from 70 to 55
to make most of the 32 mile daily round trip for chemo
on battery in her (30 mile) plugin-Prius and not use -any- gas.
(70 to 55 would save HALF the energy (due to drag) for the highway portion).
Bob
On Sun, May 16, 2021 at 3:50 PM Robert Bruninga <[email protected]> wrote:
Although drag Force goes up by square of velocity, but then power equals force
times velocity, so the power to move in the presence of drag goes up as the
Cube of velocity.
On Sun, May 16, 2021 Peri Hartman via EV <[email protected]> wrote:
square of velocity. But, yes, not linear.
------ Original Message ------
From: "Robert Bruninga via EV" <[email protected]>
Subject: Re: [EVDL] The state of EV's 1890 to 1922
Bingo, I re-read my email and when I said it goes up significantly
above 45, I omitted the fact (that you allude to) is that it goes up
as the CUBE of velocity., A huge factor. Bob
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