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Mess with your minds: A wind powered craft going faster than a tail wind speed.
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electrodacus:
See this link and scroll down to air drag https://en.wikipedia.org/wiki/Bicycle_performance
You will find two equations

This is the same that I use for max wind power available.
And this

That is incorrect (you can not always expect much from wikipedia).

To prove that equation is wrong we can just do an example.
Everything else is basically a constant so will just look at vr3 and va2*vr

Drag power at 20m/s with no wind should be the same as drag for vehicle/bicycle at 10m/s vehicle + 10m/s head wind all other things being equal.

203= 8000
202 * 10 = 4000 so half of the correct result.
Thus this sort of wrong understanding is fairly common as it ended up in Wikipedia.
Brumby:
OK ... Trying to get a feel as to where this energy storage is taking place.

Is this what you mean?



If not, then where?
electrodacus:

--- Quote from: Brumby on December 27, 2021, 03:53:58 am ---OK ... Trying to get a feel as to where this energy storage is taking place.

Is this what you mean?



If not, then where?

--- End quote ---

It is symmetrical that is why I say pressure differential. The one you marked is half, it is the side with the higher than atmospheric pressure and the other half is on the other side of the propeller the part with lower than atmospheric pressure.
So propeller is both pushed by the high pressure zone and pulled by the low pressure zone.  So energy is stored in that volume on both sides of the propeller.   
bdunham7:

--- Quote from: electrodacus on December 27, 2021, 01:10:09 am ---Thus this sort of wrong understanding is fairly common as it ended up in Wikipedia.

--- End quote ---

No, they got it exactly right here and we've all been telling you the exact same thing....

By 'this sort of wrong understanding' you mean anything that doesn't align with your misconceptions.  And yeah, that so-called 'wrong understanding' is indeed very common and will be the consensus of every sane physicist as well as almost anyone with a grasp of introductory physics (mechanics).  Are they all wrong?
electrodacus:

--- Quote from: bdunham7 on December 27, 2021, 04:20:18 am ---
No, they got it exactly right here and we've all been telling you the exact same thing....

--- End quote ---

OK then why that second formula that should represent the same thing provide a different value ?
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