General > General Technical Chat
Mess with your minds: A wind powered craft going faster than a tail wind speed.
electrodacus:
--- Quote from: bdunham7 on August 31, 2021, 05:21:46 pm ---
--- Quote from: electrodacus on August 31, 2021, 04:59:33 pm ---Yes please test a treadmill to see the difference from moving piece of paper. The difference is huge you just can not see that without doing the experiment.
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What is your theory or explanation as to why they are different?
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The simplest way I can explain is that paper rolls under the wheels while the treadmill will push the vehicle back. As the paper moves relative to ground while the treadmill is fixed to the ground.
I probably mentioned this before so if you can not see the difference between them you will just need to make a test. The treadmill can be just a simple paper loop rolling on two cylinders.
Is like having a powered treadmill vs one that is not powered but instead pushed towards the vehicle.
Alex Eisenhut:
The treadmill belt moves relative to ground, what on Earth you smoking? BC bud?
The part of the treadmill that stays fixed to the ground is equivalent to the guy's feet in the paper sheet video. :-//
electrodacus:
--- Quote from: Alex Eisenhut on August 31, 2021, 05:37:26 pm ---The treadmill belt moves relative to ground, what on Earth you smoking? BC bud?
The part of the treadmill that stays fixed to the ground is equivalent to the guy's feet in the paper sheet video. :-//
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I know it may look non intuitive to you but please think more about this or do a test.
You think that a powered treadmill is the same as a powered off treadmill that you push under vehicle ?
The vehicle needs to advance on the treadmill so if you push the treadmill under the vehicle that is not the same as a rotating treadmill.
I think this is a large point of misunderstanding so please anyone do a test as shown in my diagram and do not replace a treadmill with a flat piece of paper as they are not equivalent even if that seems the same thing to you.
I think for many of you this point needs to be clarified. So I will not answer other questions until this point is clear to everyone.
If someone understand the difference between a treadmill and that dragged piece of paper please help explain in a better way than I do.
bdunham7:
--- Quote from: electrodacus on August 31, 2021, 05:30:04 pm ---I probably mentioned this before so if you can not see the difference between them you will just need to make a test. The treadmill can be just a simple paper loop rolling on two cylinders.
Is like having a powered treadmill vs one that is not powered but instead pushed towards the vehicle.
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OK, so let's say I'm inquisitive and I want to built the treadmill, but in stages to see where this transformation takes place. I test the car at each stage as follows.
So I start with a raised platform with a frame around the edge so that all you or the car can see is a flat, moving surface surrounded by the frame.
First, I just put a piece of a paper in there and move it towards the car.
2nd, I put a roller on the front and wrap a long piece of paper around it so that I can move the paper by just pulling the bottom part backwards.
3rd I glue my paper in a loop, but just keep pulling the bottom part away from the car continuously to keep the top surface moving towards the car at a constant speed.
4th I add a back roller and loop the paper tightly around both rollers and again keep pulling the bottom part backward to keep the top surface moving.
5th I put a crank on the back roller and keep the paper moving at a constant speed .
So ejeffrey's video shows the first step--just the paper--and the car obviously moves from left to right, as we all expected. According to your assertion, if we arrive at step 5 here, the car will NOT move from left to right. So, if you can, tell us at what step the car will stop behaving as it did in the video and start behaving as you say it will in the end? And since all 5 steps involve a surface that is moving in the same direction at the same rate, what allows you or the car to tell the difference?
bdunham7:
--- Quote from: electrodacus on August 31, 2021, 06:06:13 pm ---I know it may look non intuitive to you but please think more about this or do a test.
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It's not about intuition, it's about logic and math. In each case the two surfaces are moving at the same rate in the same direction. What other characteristic could that surface have that would change how it interacts with the car?
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