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Mess with your minds: A wind powered craft going faster than a tail wind speed.
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Labrat101:
This is just an endless Loop of Insanity .
@ electrodacus  ."" would argue Black is white Because !!  ""
Plus he has a duplicate Thread that it also an endless Rabbit Hole Maybe someone should Lock it ..
As say ..
fourfathom:
I see no need to lock either of the threads.  If you aren't interested in futile arguments, then just don't read the thread.  Me, I sometimes enjoy them.
electrodacus:

--- Quote from: Kleinstein on December 12, 2021, 10:27:17 am ---
--- Quote from: electrodacus on December 12, 2021, 03:45:22 am ---
If you think I'm wrong please provide the "correct" equation.
The one Derek provided in his video is clearly wrong as it will make bad predictions for both case A and case C sine his equation include (v-w) instead of the correct (w-v)   w-wind speed v-vehicle speed.

--- End quote ---
The correcrt equations / explainartions were given multiple time - just read them and understand or show, were you think they are wrong.

--- End quote ---

Have I not just done that ? Have you even read my comment ?

You care about the wind power available to vehicle as that is what allows you or not to accelerate and the correct formula for that in case of a vehicle traveling directly downwind is
0.5 * air density * area * (wind speed - vehicle speed)^3

The conclusion for this correct formula is that there will be zero wind power available to any wind powered vehicle traveling directly downwind.
So no wind powered vehicle can ever exceed wind speed unless it has an additional energy source or as is the case here an energy storage device.
electrodacus:

--- Quote from: Brumby on December 12, 2021, 11:24:58 am ---Are we back into this brick wall headbutting exercise again...?   :palm:

The simple fact is that the Blackbird can do what is claimed.  It has been proven experimentally - except someone doesn't want to admit something than runs counter to their intuition.

Many members have pointed out errors in their argument, yet they refuse to concede any of them.  Stubborn and ignorant ... it's a fool's errand to try and correct them.  I've not the time to waste any more on this silliness.


Dunning–Kruger is strong in this one.

--- End quote ---

The blackbird vehicle works exactly the way I describe it and that involves energy storage.  I never claimed that blackbird test results are not exactly correct.
 The explanation Rick and Derek have provided is completely flawed and to justify their wrong intuition they changed a formula to look like data fits their description (it is not even with the wrong formula).

There is no power available from wind for a vehicle traveling at the same speed as wind speed directly downwind. This is a fact that only someone that has no understanding of the physic involved will make.
 
IanB:

--- Quote from: electrodacus on December 12, 2021, 05:59:32 pm ---You care about the wind power available to vehicle as that is what allows you or not to accelerate and the correct formula for that in case of a vehicle traveling directly downwind is
0.5 * air density * area * (wind speed - vehicle speed)^3
--- End quote ---

And as I keep telling you, that is not the correct formula. The correct formula is:

available power from wind = 0.5 * air density * area * (wind speed − ground speed)^3

If you keep putting vehicle speed in there you will get the wrong conclusion.


--- Quote ---The conclusion for this correct formula is that there will be zero wind power available to any wind powered vehicle traveling directly downwind.
So no wind powered vehicle can ever exceed wind speed unless it has an additional energy source or as is the case here an energy storage device.

--- End quote ---

And this is the wrong conclusion. The vehicle can draw power from the wind when going faster than the wind, because the vehicle is in contact with the ground using wheels that do not slip.

It has also been explained to you many times that there is no energy storage in the vehicle. It has no springs, batteries or flywheels. There is no possibility of "pressure energy" behind the propeller, as there are no walls and there is no containment. It works purely by drawing power from the wind, using a mechanical system to make the velocity component of the propeller blades in contact with the air be less than the wind speed.
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