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Old 04-07-2021, 07:32 PM   #91 (permalink)
aerohead
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relevant

Quote:
Originally Posted by JulianEdgar View Post
None of that is relevant when we are talking about the drag coefficient penalty of cooling systems!

Like, it's why we use coefficients not absolute values.

If you think we need to be measuring speed, I guess that's one reason you're confused regarding the idea of cooling system drag as a percentage of the total drag coefficient.
1) You are absolutely correct within a very narrow reading.
2) What may escape us is, that the cooling load itself will also vary geometrically with velocity, and must be parameterized specifically to the operational envelope.
3) The motor/battery cooling percentage of overall drag for the Tesla Model S, at 77.5 miles per hour would be 1%, instead of 8%.
4) The Taycan Turbo S would be 2% at 80-mph, instead of 16%.
5) If the Taycan and Model S were not designed for 160/155 mph, we'd never see the 16% and 8% values. Their radiators could be 1/8th the size that they are and easily cover the Btus coming their way. This fact is hiding in plain view.

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