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

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Kleinstein:
The typical molecule velocity from the thermal movement is about at the speed of sound.

The propeller in the prop driven vehicle makes the air around the propeller to more slower than the wind. So the wind can push against that moving air.
Relative to the vehicle that air mores in the opposite direction of the travel, but relative to ground the air pushed by the prop is still moving in the direction of the wind and vehicle.

electrodacus:

--- Quote from: dunkemhigh on September 17, 2021, 08:53:11 am ---
--- Quote ---I'm not wrong. If I was wrong one of you will have been able to explain where I'm wrong.
--- End quote ---

Conversely, if you were right one of us would have been able to understand your explanation.

--- End quote ---

Fair point.


--- Quote from: dunkemhigh on September 17, 2021, 08:53:11 am ---You're using a non-sequitur as proof, and not just in this example.

--- End quote ---

I needed to google non-sequitur.
There may have been small mistakes that I made like assuming treadmill will be different from a dragged paper.  I just looked at the experimental result and concluded that was not possible from theory with a treadmill so lazy way of thinking lead me to the wrong conclusion that they are somehow different.
That is the same sort of mistake you are doing when looking at the blackbird test result or the small treadmill prototype of blackbird.

While not related with blackbird this wheel only cart and how it can advance forward is an interesting problem that is also wrongly interpreted.
There is a hysteresis for the wheel slip and that together with energy storage is what allows this wheel cart vehicle advance in the opposite direction to treadmill or paper road direction.
I will try to find some time to make a video that better show what I'm saying as I ordered a toy wheel car on amazon and just got that yesterday.
What I can show is that by moving the paper slowly under the front generator wheels the front wheels move while the back wheels do not move at all and since the wheels are connected (by an elastic rubber band) energy is stored in that.
Then at some point front generator wheels start to slip and since at that point lower power is needed the stored energy in the belt can move the vehicle forward by rotating the back wheels then this will repeat.
So there is generating and storing energy while vehicle is stationary then at the point the generator wheel starts to slip the stored energy is put in the back wheel that drives the vehicle forward.
If you think there is no hysteresis here is one of the many papers on that https://deepblue.lib.umich.edu/bitstream/handle/2027.42/93899/bojanad_1.pdf

electrodacus:

--- Quote from: Brumby on September 17, 2021, 10:11:42 am ---
--- Quote from: electrodacus on September 17, 2021, 01:34:51 am ---If I was wrong one of you will have been able to explain where I'm wrong.

--- End quote ---
We have tried.  Several dozen times.  What prevents us from being successful is your steadfast refusal to consider, let alone accept the arguments that have been put before you - and your continued reliance on your own, flawed beliefs.  Even there, we have tried to explain the flaws, but you seem incapable of accepting that possibility.

You think you're right - and that's as far as your thinking goes.

How can we explain where you're wrong when you won't even listen?

--- End quote ---
I promise I will never refuse a sound argument.
Seems you refuse to understand that above wind speed no energy can be extracted from the wind (at least not useful energy that will be able to accelerate the vehicle forward). If you want to break the vehicle then yes you can use wind energy for that when above wind speed but that is not what you want or claim that happens.
We are also talking about a very specific case where vehicle drives in the same direction as the wind as at any angle to wind direction there will be air molecules driving faster than vehicle.

electrodacus:

--- Quote from: Kleinstein on September 17, 2021, 02:16:27 pm ---The typical molecule velocity from the thermal movement is about at the speed of sound.

The propeller in the prop driven vehicle makes the air around the propeller to more slower than the wind. So the wind can push against that moving air.
Relative to the vehicle that air mores in the opposite direction of the travel, but relative to ground the air pushed by the prop is still moving in the direction of the wind and vehicle.

--- End quote ---

You will be the only one to make this claim.  Wind is different and separate for the random motion of air molecules due to air temperature.
This vehicle is advertised as wind power not thermal powered.
Yes air molecules movement relative to vehicle is what is important and when vehicle is below wind speed wind energy can be used to accelerate the vehicle.  When vehicle exceeds wind speed (same exact direction of travel as the wind) the air molecules move in the opposite direction so it will oppose the vehicle that will be the opposite of helpful.  The sign basically changes.
And if someone just reads this I need to mention that I know blackbird can drive significantly faster than wind speed it is just that the reason it can do that is stored energy not the fact that it can use in any way wind energy directly as that is just impossible in this particular case.

PlainName:

--- Quote ---since the wheels are connected (by an elastic rubber band)
--- End quote ---

Don't use an elastic band - it is introducing something that's not necessary and just confuses things (such as, allowing you to claim energy storage). Ideally use a toothed belt, but failing that a tight piece of string would be better.

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