Quote:
Originally Posted by JulianEdgar
[Groan] More smoke and mirrors.
Single figures for cooling drag are published for cars all the time - maybe do a literature search?
You've often stated that a car had such a and such a drag figure, and if it were electric, then it would have a [much lower] figure. Maybe you've forgotten what you've written?
Never mind. We all know now to point out the error when you repeat it.
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1) cooling systems free of shutters would be within bounds for a single quanta. The authors would be obligated to state the conditions.
2) any vehicle with shutters must be reported as a 'range' of percentage. By default, it cannot be a single value.
3) if active air-suspension is part of the mix, the vehicle must be reported for the range of body height.
4) if the vehicle has an active airdam, ditto.
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*As to 'often reported' I'm referring to garden variety, family passenger cars, not sports cars, high performance sports cars, or supercars.
* Your Taycan and Model S are not germane to passenger cars due to their maximum attainable velocities.
* You know that aerodynamic drag power requirements vary with the cube of the velocity.
* You must also know that if you're cooling a motor or batteries, that the aerodynamic portion of that cooling load will also vary as the cube of the velocity.
* 155- cubed, divided by 77.5-cubed will give you the difference in radiator size for the aerodynamic power-related cooling load for the Tesla Model S at theses two speeds. Some BEVs won't even go 77.5-mph! This is part of the 'context' which must be part of the discussion, or else it borders on complete intellectual dishonesty.
* The percentages you have for both Tesla and Porsche had better have this kind of information or it will be completely useless!
* God lives in the details.
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a) Some of your own shared materials imply that air-cooled battery BEVs could enjoy a Cd 0.025 advantage as far as losing the conventional cooling system, plus Cd 0.010 advantage of a smooth belly pan. A Cd 0.035 advantage.
b) If you take your Porsche Taycan Turbo, at Cd 0.22, and add back Cd 0.035, you get Cd 0.255, about as good as the 1975 Ferrari Cr 25. This is the 'CONTEXT' of my comments.
c) we can say, Gee, look at how low the drag is on that Taycan. Or we can say ' Ho -hum, yeah, we saw that forty-five years ago.'
d) this is 'CONTEXT'.
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Bjorn Nyland reported his Autobahn-test Tesla Model S results. Low and high performance variants. Watts/ mile vary by 40% between the two Model S's. Radiator sizes could vary 40%. Cooling drag could vary 40%.
Your paper needs to parse this sort of thing out! CONTEXT!
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If you've been given privileged materials under the condition that certain information not be disclosed as a condition of the 'giving', this may lead to unresolvable 'push-back' issues.
All I can say is that, the more info the better. There's no such thing as 'too much.'