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| electrodacus:
--- Quote from: gnuarm on July 11, 2022, 12:28:59 am --- No, you don't understand. Relative to the car, the sail moves toward the wind. With 1:1 gearing relative to the ground, the sail doesn't actually move at all, with 4:3 gearing it moves relative to the ground at 1/4 the speed of the car. Stop trying to muddy the waters. This car will clearly move down wind, at speeds greater than the wind, only limited by the frictional losses. You insistence in applying an erroneous calculation to the Blackbird car is fixed by this model where your equation does apply, since the wind is blowing into sails, not the air movement produced by the propeller. --- End quote --- OK so both the sail and the car moves in the same direction as the wind just at different speeds. Getting to 1.2kg balls traveling at 10m/s When vehicle speed relative to ground is below 10m/s balls will hit the sail and transfer kinetic energy to vehicle. When vehicle speed is the same as wind speed no balls (no air particles) will be able to hit the moving sail's The sails move around the vehicle. You may need to see an animation if you can not visualize that. The 1.2kg ball has the exact same speed as the vehicle so it will follow the vehicle but never be able to hit any sail mounted to the vehicle even if the sails move around the vehicle they move half the time in the direction the vehicle moves faster than the vehicle (folded under the vehicle) and half the time they move in the opposite direction above the vehicle but the average will be the speed of the vehicle as they are part of the vehicle. |
| electrodacus:
--- Quote from: gnuarm on July 11, 2022, 12:43:51 am ---I'm not sure, but I think ED is playing dumb so he doesn't have to deal with the reality of this car which clearly can move down wind faster than the wind. He will insist on changing the case and turn it into something where he can obfuscate and confuse the facts. --- End quote --- The vehicle you propose can move faster than wind if you provide that vehicle with an energy source (battery and an electric motor for example). If wind power alone needs to power the vehicle then it will also work but only at a speed below wind speed if no energy storage of any type is available like pressure differential that you prefer to ignore it exist (air is a compressible fluid if you understand the meaning of that). Exchange the air for 1.2kg balls or water where there is no pressure differential possible as water is a non compressible fluid and your vehicle can not exceed wind speed. With air it will exceed wind speed thanks to pressure differential energy storage but it will be above wind speed only for as long as that stored energy can accelerate the vehicle. When that stored energy is used up the vehicle will start to decelerate (due to friction losses) until it drops below wind speed. You have seen incomplete tests as both blackbird stopped before the vehicle used up all stored energy and treadmill model has to little space before it runs out of track. Especially with treadmill where there are less variable and more controlled environment you can see how acceleration rate drops as stored energy is used up and you can calculate exactly when it will stop accelerating based on the rate at which the acceleration rate drops. |
| electrodacus:
Maybe as this is an electrical forum people here have a bit better intuition about electricity (possibly just wishful thinking on my part). Input is a CV-CC lab power supply rated at 200W 20V and 10A max Say you want 30V. Is it possible to add a circuit between the output of the 200W lab power supply that has no energy storage device and get 30V on the other side? What about 15A ? What about more than 200W for some limited amount of time? Is any of that possible without having a energy storage device in that circuit ? |
| gnuarm:
--- Quote from: electrodacus on July 11, 2022, 12:46:54 am --- --- Quote from: gnuarm on July 11, 2022, 12:28:59 am --- No, you don't understand. Relative to the car, the sail moves toward the wind. With 1:1 gearing relative to the ground, the sail doesn't actually move at all, with 4:3 gearing it moves relative to the ground at 1/4 the speed of the car. Stop trying to muddy the waters. This car will clearly move down wind, at speeds greater than the wind, only limited by the frictional losses. You insistence in applying an erroneous calculation to the Blackbird car is fixed by this model where your equation does apply, since the wind is blowing into sails, not the air movement produced by the propeller. --- End quote --- OK so both the sail and the car moves in the same direction as the wind just at different speeds. Getting to 1.2kg balls traveling at 10m/s When vehicle speed relative to ground is below 10m/s balls will hit the sail and transfer kinetic energy to vehicle. When vehicle speed is the same as wind speed no balls (no air particles) will be able to hit the moving sail's --- End quote --- You aren't understanding. The sails move at a quarter the rate of the vehicle. So when the vehicle is moving at twice the speed of the wind, the wind is still hitting the sails at one half the wind speed relative to the ground. --- Quote ---The sails move around the vehicle. You may need to see an animation if you can not visualize that. --- End quote --- Uh, no, the sails move from the front of the vehicle to the rear in a straight line along a belt. The sails collapse on reaching the rear, so they can follow the belt under the vehicle and be pulled back up on reaching the front of the car. I created this model. If you don't understand, I suggest you create an animation to help you visualize it. --- Quote ---The 1.2kg ball has the exact same speed as the vehicle so it will follow the vehicle but never be able to hit any sail mounted to the vehicle even if the sails move around the vehicle they move half the time in the direction the vehicle moves faster than the vehicle (folded under the vehicle) and half the time they move in the opposite direction above the vehicle but the average will be the speed of the vehicle as they are part of the vehicle. --- End quote --- You literally can't understand this can you? The only speed of the sail that matters, is the speed when it is catching the wind. At that time it is moving wrt to the ground slower than the wind, so receives power from the wind, while the car is moving forward, faster than the wind. Please create the animation. But if you think the velocity of the sail when it is folded up has anything to do with the problem, there is nothing anyone can say to you to help you understand, or.... you do understand, but you are not capable of acknowledging you have been wrong all this time. Even money, either way. |
| gnuarm:
--- Quote from: electrodacus on July 11, 2022, 12:57:25 am --- --- Quote from: gnuarm on July 11, 2022, 12:43:51 am ---I'm not sure, but I think ED is playing dumb so he doesn't have to deal with the reality of this car which clearly can move down wind faster than the wind. He will insist on changing the case and turn it into something where he can obfuscate and confuse the facts. --- End quote --- The vehicle you propose can move faster than wind if you provide that vehicle with an energy source (battery and an electric motor for example). If wind power alone needs to power the vehicle then it will also work but only at a speed below wind speed if no energy storage of any type is available like pressure differential that you prefer to ignore it exist (air is a compressible fluid if you understand the meaning of that). Exchange the air for 1.2kg balls or water where there is no pressure differential possible as water is a non compressible fluid and your vehicle can not exceed wind speed. --- End quote --- It doesn't matter how many times you say this, it still won't be true. This is a simple case as you can get. You provided the equation of the wind interacting with the sail which shows this will work. That equation does not depend on any storage of energy or any other nonsense you come up with. It is as fundamental as the downwind sailboat example it was created for. Now you are just kidding yourself. --- Quote ---With air it will exceed wind speed thanks to pressure differential energy storage --- End quote --- Blah, blah, blah. The sail does not exceed the speed of the wind, so the equation applies perfectly. --- Quote --- but it will be above wind speed only for as long as that stored energy can accelerate the vehicle. --- End quote --- Blah, blah, blah... you can't squirm your way out of this with your nonsense. None of that applies to a sail boat. This is just a sail boat geared to the car. Wind on sail, moving the car faster than the wind, while the sail moves slower than the wind. There is no energy storage bunkum like you want to apply to the Blackbird. --- Quote ---When that stored energy is used up the vehicle will start to decelerate (due to friction losses) until it drops below wind speed. You have seen incomplete tests as both blackbird stopped before the vehicle used up all stored energy and treadmill model has to little space before it runs out of track. Especially with treadmill where there are less variable and more controlled environment you can see how acceleration rate drops as stored energy is used up and you can calculate exactly when it will stop accelerating based on the rate at which the acceleration rate drops. --- End quote --- You are so full of it. |
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