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Mess with your minds: A wind powered craft going faster than a tail wind speed.

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Alex Eisenhut:
This is Wind Cube territory, with apologies to real companies called Wind Cube.

electrodacus:

--- Quote from: bdunham7 on September 01, 2021, 11:46:20 pm ---Assuming without checking or agreeing that your math is correct...

6Wh = 21600Ws

4800Ws = 1.5Wh.

and so on.  Not keeping your units tidy can make things look different--and wrong.

and then you have to ask by what mechanism is the propeller compressing this air if the wind is pushing the vehicle and not the other way around?

--- End quote ---

The wind is pushing the vehicle and the blackbird takes a big part of that energy and put it back in the propeller generating an "artificial wind" in the opposite direction. When vehicle is way below half the wind speed the so called artificial wind will be stronger than the actual wind and this is where energy is stored as pressure differential.
But even before getting to wind speed this pressure differential will start to drop as the stored energy is already being used and at some point the pressure differential is so small that it can no longer cover the vehicle friction and that is the point of max speed from witch point the vehicle will start to decelerate.


Yes I should have used maybe just one unit like Ws but for most people Ws has no much meaning compared to Wh where most people may know that 6Wh is about half of what you have available in a smartphone battery.
Many people may also own an eBike and may know what 6Wh compared to their eBike battery of of maybe 500 to 600Wh so they can do 100x of those records with the energy in their eBikes.
But Ws are easier to use when making calculations as is the same with Joules.
In any case you do have a point.

bdunham7:

--- Quote from: electrodacus on September 02, 2021, 12:03:01 am ---The wind is pushing the vehicle and the blackbird takes a big part of that energy and put it back in the propeller generating an "artificial wind" in the opposite direction. When vehicle is way below half the wind speed the so called artificial wind will be stronger than the actual wind and this is where energy is stored as pressure differential.

--- End quote ---

How can there be an 'artificial wind' coexisting with and opposite to the actual wind?  Can you demonstrate that somehow with a fan or something?

And setting that aside, if the resultant artificial wind is stronger than the real wind, where would the energy for that come from?  Wouldn't that violate your conservation of energy principles?

electrodacus:

--- Quote from: Alex Eisenhut on September 01, 2021, 11:54:50 pm ---This is Wind Cube territory, with apologies to real companies called Wind Cube.

--- End quote ---

Not quite sure what you want to say by wind cube territory. It seems Wind Cube (never heard of them) make some wind speed measuring devices.
I designed my own wind turbine and wind turbine calculated about 10 years ago. I just never build it as solar PV was just way more cost effective and it did not made any economic sense to build or even buy a wind generator to power my house.
My English is quite bad so it may be hard to watch this old video :)

 

electrodacus:

--- Quote from: bdunham7 on September 02, 2021, 12:08:19 am ---
--- Quote from: electrodacus on September 02, 2021, 12:03:01 am ---The wind is pushing the vehicle and the blackbird takes a big part of that energy and put it back in the propeller generating an "artificial wind" in the opposite direction. When vehicle is way below half the wind speed the so called artificial wind will be stronger than the actual wind and this is where energy is stored as pressure differential.

--- End quote ---

How can there be an 'artificial wind' coexisting with and opposite to the actual wind?  Can you demonstrate that somehow with a fan or something?

And setting that aside, if the resultant artificial wind is stronger than the real wind, where would the energy for that come from?  Wouldn't that violate your conservation of energy principles?

--- End quote ---

No it will not violate the conservation of energy as all this is done when you have access to wind energy since you are well below wind speed.
Think about this way. You have a large wind turbine generator in low wind speed supplying a much smaller fan that creates even hurricane level winds but since the diameter of the fan is much smaller much less wind is actually moved so is like a gear box.
So say you will want to use the fan to supply the wind turbine then that will not work as power output is much smaller from the fan than what the wind turbine will need to supply the fan.
The propeller is like a diode it can leave air molecules travel from upwind to down wind but not the other way around so it acts as a one way sail while spinning.
In any case no conservation of energy is broken as energy is stored. You could as well drive a EV with empty battery just use regenerative brakes while pushed by the wind then after you stored enough just accelerate to whatever speed you want but only for a limited time depending on how much you spent storing energy.
That is why the Blackbird will work even in a day with no wind just push the vehicle to sufficient speed to charge the energy storage and vehicle will drive faster that the speed you pushed it at for some limited amount of time.

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