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

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electrodacus:

--- Quote from: Brumby on August 31, 2021, 04:45:34 am ---But two 'sets' of wheels is not an appropriate analogue.

Excluding the propeller and it's interaction with the air is as relevant to this discussion as me saying I want to test a space suit by jumping into a pool with it.  Whatever else it might simulate, such an exercise does not reflect the real world environment.

Your wheels argument does not reflect the real world environment governing the blackbird AT ALL.

Continuing to do so simple underlines your ignorance, stubbornness and, dare I say (what is increasingly difficult to dismiss) your delusion.

--- End quote ---

In my diagram the generator wheel is exactly the same as the Blackbird back wheels while the motor wheel is the equivalent of the propeller.
This is about the same experiment as the small propeller cart running on a treadmill in Derek's video. The difference is that instead of propeller pushing against air there is a motor wheel pushing against the ground.  This is meant to show that since you have a wheel and a solid there is no way to store energy like it is the case with propeller and air (air is compressible so energy can be stored and that is the reason the vehicle can accelerate forward for some limited amount of time).
So my wheel experiment is exactly the same as blackbird just without the energy storage showing that without energy storage it will not work.
It will be more complex but blackbird type vehicle will also not work under water (driving at the bottom of a river) since water is not compressible. In case of water you will have a propeller but you can not exceed water speed even for a little bit since there is no energy storage to be able to do that.

When I ask how is the vehicle powered when above wind speed in the same exact direction as wind since no air molecule can push the vehicle the answer is it takes energy from the vehicle kinetic energy by breaking the wheel and that energy is then transferred to wind turbine that then accelerates vehicle.
The problem with that explanation is that propeller even if 100% efficient  can not put back the kinetic energy taken from the wheel and have some extra to increase that kinetic energy meaning increase speed.   

Brumby:

--- Quote from: bdunham7 on August 31, 2021, 04:53:00 am ---
--- Quote from: Brumby on August 31, 2021, 04:45:34 am ---Your wheels argument does not reflect the real world environment governing the blackbird AT ALL.

--- End quote ---

Wait a second!  The wheeled models are demonstrating a principle, they don't have to cover all aspects of the real world operation of the original vehicle in question.  The fact that we can't agree on the basic principle of how forces can be made to operate given two mediums/objects/surfaces/whatever moving relative to one another makes it pointless to continue on further to discuss the full vehicle.  Sort of like if we can't agree on how levers work, there's no point in discussing gears.

--- End quote ---

I look at the wheels discussion as stepping into over unity thinking.  This is what I see electrodacus trying to do, so that they can dismiss any arguments against their position as "defying the laws of physics".  IMO it as a complete distraction from the heart of the matter.

The only thing I see being gained from this path is to demonstrate they are, in fact, unable to comprehend some basics and even less able to be open minded.

Brumby:
OK.

Since you claim to have all the answers with the physics knowledge and maths to support your conclusions, I put this challenge to you....

Take all reasonable references from the blackbird example and generate the maths to describe its operation.  Once you have done that, the run time limitation of such an experiment - which you claim will occur - should naturally fall out of those equations.  Please tell us what that time limitation will be, so that it can be validated experimentally.

The onus on doing this falls on YOU - not everybody else here - as
(1) You are the one claiming what was demonstrated in the Veritasium video is incomplete
and
(2) Those of us who understand the principle as it was presented agree that the demonstration proves the point.

You need to prove your point.

Brumby:
Or, you can pull a number of of thin air - just make sure the error bar is included.

For example if you say "5 minutes" and the experiment runs for 10 minutes at higher than wind speed, then don't turn around and say - "Oh, it must be longer".


Pick a number and stick to it.

IanB:
The interesting thing about the treadmill experiment is that they missed an opportunity to show something more. They let the model vehicle fly forwards and drive off the end of the treadmill. But if they had simply anchored it in place with some thread, they could have shown it pulling against the thread indefinitely while the treadmill was running.

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