https://ecomodder.com/forum/member-a...sugar-cube.jpghttps://ecomodder.com/forum/member-a...oads-up-18.jpghere are some numbers I pencil-whipped for the Chevy BOLT I'll be getting in September.
I used Cd 0.31, Af 25.7-sq-ft, 0.00238 slugs air density, and 3,880-lb test weight.
Aerodynamic horsepower requirements are presented in 5-mph increments, from zero-to 100-mph:
0-mph = 0
5-mph = 0.0067
10-mph = 0.054
15-mph = 0.183
20-mph = 0.435
25-mph = 0.8497
30-mph = 1.4683
35-mph = 2.3316
40-mph = 3.4805
45-mph = 4.9557
50-mph = 6.7979
55-mph = 9.048
60-mph = 11.7468
65-mph = 14.9351
70-mph = 18.6535
75-mph = 22.943
80-mph = 27.8444
85-mph = 33.3983
90-mph = 39.6456
95-mph = 46.6371
100-mph = 54.3836
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Over the same speed spread, power absorbed from rolling-resistance increased linearly, from zero, to 8.9873-hp ( using a Cfrr of 0.008686291 ( probably 'high' )) [ Bridgestone Ecopia is around 0.005 ].
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If everyone constructs one of these tables from 'day one', 'curves' can be constructed from the data-plots for aero and R-R, plus adjustment for mechanical efficiency, and presuming a constant BSFC, or BSFC-e for BEVs, one can predict, at any chosen velocity, what mpg, or 'range' their vehicle will return.
I photo-reduced my table and chart, in full color, at a local UPS/ Post Office store, and laminated it, creating a 'card' which fits in my fanny pack or clipboard, for 'thinking' and trip-planning.
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PS:
Because I ran these numbers, I know from the science that with aero mods, the BOLT has a shot at over 300-miles range on it's 'recall' 63-kWh pack, before I've bought it.
'Knowledge is Power'
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Extra PS:
here's a very old, pre-radial tire power graph for rolling-resistance vs velocity. It's 'nothing' compared to aerodynamics
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extra extra PS
Here's the aerodynamic challenge. The hen egg and sugar cube have identical drag ( Thanks to Chrysler Corporation for the data ).
The hen egg is 21-X larger than the sugar cube, yet 'same' drag.