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Originally Posted by redpoint5
That guy claims the truck has something like a .41 Cd at 60 MPH, and somehow it drops to .3 at 88 MPH. How does Cd change with speed? I thought it was a constant value.
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Drag coefficient does vary with the inverse square of speed*, but because of that inverse square relationship it's so small as to effectively be constant over the speeds a passenger car sees.
Last night Musk tweeted:
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With extreme effort, Cybertruck might hit a 0.30 drag coefficient, which would be insane for a truck. Requires tweaking many small details.
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Sounds like it's above 0.30 now but could reach that for production.
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*This is a bit of a simplification--it assumes supercritical Reynolds number (as the flow field transitions from laminar to turbulent over a car, Cd decreases suddenly, but this happens at a low speed). A car going 60 mph vs. 88 mph: there should be no change in Cd.