I think it's interesting, how the keyboard warriors on Usenet were objecting. A land craft can sail, using a windmill, direct upwind faster than the wind; a water craft has enough resistance that that would be impossible at practicable scales, but using a windmill you can absolutely generate enough power from the apparent wind to get somewhere. If I build a boat (which tbh I won't, just economically restricted) I will absolutely include a large deployable wind turbine (as well as a deployable traditional-ish sail system, when I want to sail outside of the no-go zones since I would sacrifice the directional pivot on the turbine for simplicity), and after proving I can, I will invite aboard anyone who thinks you cannot sail directly into the true wind.
@ZKMX7 But directly downwind faster than wind is not that easy. At least not on water. When will you build a DDWFTTW boat? With all your experience with directly upwind you would have a good chance achieving it.
so im assuming the boat uses the same thing? and with the boat does it have a propeller or a paddle wheel? if u used a propeller did u have a right angle gear drive or just more pulleys?
@ZKMX7 do u think it might be more efficient with a paddle wheel, i mean it might even be easier to have the pulleys link up to it. could u also take like the gears from a bike so u cold have like a six speed prop?
@ethankern No gear drive. With these small models a gear drive soaks up too much power. Might by ok with a big man-carrying one. You are right there is a big propeller under the water on the boats.
@joekinney Downwind is easy and, as you say, a standard sail might be better. This one is all about going upwind directly, which can't be done with any other method.
I said the tip speed slows down changing to a lower ratio. I meant the tip speed increases. The wind is pushing from a radius closer to the center of the rotor. The rotor is the engine. Going from 5th to 4th revs the engine up, but you cant make the wind faster.
@ethankern I don't think paddlewheels would work as well. Wern't paddlewheels overtaken by props more than 100 years ago? Just think why that was. The six-speed prop is not a bad idea, but unsuitable for small models. If you have ideas, why don't you make one yourself? It's not too difficult.
Say your turbine is turning 50 rpms and your prop is turning 500rpms because you are using a ratio of 0.9. At this hypothetical moment the wind is pushing the turbine from three points on the rotor at a radius of 100cm. If you change ratios to 0.8 the turbine slows down to 45rpms. The wind will start pushing at three points on the turbine at a smaller radius of 89cm. I am having trouble now because I over simplified. The power coming out of the prop is pushing water. The prop pushes the water from an average radius on the prop. That radius also changes. The only function of the transmission is to control the tip speed of the rotor. Go too slow and it will stall. Really, that is not asinine. That makes the boat safer. I apologize.
This might interest you: th-cam.com/video/wrro4MxNr7Y/w-d-xo.html It is basically the same thing as you bade but then BIG and its an international race event!
@ethankern It's just string. Tensioned with jockey pulley and elastic band. with rubber faced pulleys cut into bands from rubber gloves. Goes thro 90 degrees to go back to drive wheel. Check website
@ethankern I meant you could make a small model maybe. Anyway, later you may be able to make one and then you will have all the information. It's all on the website.
@ZKMX7 I would love to make a full sized one but I don't really have access to those kinds of mattereals. And I have a ton more questions. I've just mainly been scribbling things down in a note book. Like what might work and what might not and I really like having someone that's done this before and can say yeah this would work.
It seems to me that if this device would accelerate with a 10 mph wind blowing, then pushing it at 10 mph on a windless day would also accelerate it, in which case you would have perpetual motion, yes?
No, it only works on the difference between windspeed and groundspeed. I'm sure you know that perpetual motion is impossible. You've said it yourself - if you had to push it - you would be putting energy into it and it would not be perpetual motion.
Pete, If the vehicle can accelerate even one kt when it faces a 10 kt wind against its propeller, it must overcome the static coefficient of friction on its wheel bearings, yes? On a windless day, with you pushing it at 10 kts, which produces that same relative wind of 10 kts on the propeller, it only has to overcome the dynamic coefficient of friction in order to accelerate, yes? So with the same relative winds impacting the machine, it should accelerate and leave the 10 kt pushing force behind. Just like pushing a toy cart up a hill, as soon as you reach the top of a hill and the force of gravity then starts accelerating the vehicle, it just wanders ahead of you. The machine does not "know or care" what the wind speed is relative to the ground. It is only concerned with the relative speed against the propeller. That is what makes the propeller turn, yes?
Peter, Surely you can see that if the vehicle accelerates when exposed to a certain velocity of wind, then pushing the vehicle down wind at the same speed would reduce its relative wind to zero and there would be nothing to propel it, even though the wind relative to the ground would remain the same. Can you see then that therefore it is only the relative wind that affects the propeller, not the wind relative to the ground.
Firstly, it is not a propeller it is a wind turbine - a propeller propels (the clue is in the name) whereas a turbine collects and is turned by the wind (the opposite). The machine certainly, does know the windspeed relative to the ground because the ground is connected to the wheels and the wheels are connected to the turbine. The two are connected. Pushing it into the wind on a windless day does not work. Because the apparent wind over the blades is exactly the same as the speed of the wheels. There is no power available because the 2 mediums are travelling at the same speed. Only when the wind on the blades is MORE than the speed of the wheels will power be produced.
I think you are missing the basic physics here. Newton's first law states that a body in motion tends to stay in motion and a body at rest tends to stay at rest. What that means is in order to set a resting body into motion requires force and likewise a moving body that is acted upon by the same force will accelerate just as the resting body will. So let's consider an ideal frictionless condition and connect your turbine to a variable transmission that can impart torque to the wheels whether they are moving or standing still. If the wind speed of X mph will make the machine at rest accelerate giving it a velocity relative to the wind of X+ε, then the wind created by pushing the machine at the same speed will generate the very same amount of power, which through the transmission will impart the same torque, thus accelerating the vehicle by the same ε mph. Keep in mind that it only takes force to accelerate the machine to X mph and thanks to Newton's first law, no force is required to keep a body in motion that is already in motion. But the wind created by the body that is now in motion, acting on the turbine will create a torque just as it did to the machine when it was at rest. So yes, it takes force to bring the machine up to X mph but once there, it will run by itself forever, in fact accelerate to X+ε. Does that make sense?
I think it's interesting, how the keyboard warriors on Usenet were objecting. A land craft can sail, using a windmill, direct upwind faster than the wind; a water craft has enough resistance that that would be impossible at practicable scales, but using a windmill you can absolutely generate enough power from the apparent wind to get somewhere. If I build a boat (which tbh I won't, just economically restricted) I will absolutely include a large deployable wind turbine (as well as a deployable traditional-ish sail system, when I want to sail outside of the no-go zones since I would sacrifice the directional pivot on the turbine for simplicity), and after proving I can, I will invite aboard anyone who thinks you cannot sail directly into the true wind.
@ZKMX7
But directly downwind faster than wind is not that easy. At least not on water. When will you build a DDWFTTW boat? With all your experience with directly upwind you would have a good chance achieving it.
so im assuming the boat uses the same thing? and with the boat does it have a propeller or a paddle wheel? if u used a propeller did u have a right angle gear drive or just more pulleys?
@ZKMX7 do u think it might be more efficient with a paddle wheel, i mean it might even be easier to have the pulleys link up to it. could u also take like the gears from a bike so u cold have like a six speed prop?
@ethankern
No gear drive. With these small models a gear drive soaks up too much power. Might by ok with a big man-carrying one. You are right there is a big propeller under the water on the boats.
@videofizyka Thanks for your confidence! I have done a few tests but they didn't look promising. It may be possible, but I haven't got there yet.
@joekinney Downwind is easy and, as you say, a standard sail might be better. This one is all about going upwind directly, which can't be done with any other method.
now how does the pulley system work? im really interested in this stuff
Using a transmission between the wind turbine and a prop is asinine. The three blade wind turbine and the aqueous prop are both continuously variable.
I said the tip speed slows down changing to a lower ratio. I meant the tip speed increases. The wind is pushing from a radius closer to the center of the rotor. The rotor is the engine. Going from 5th to 4th revs the engine up, but you cant make the wind faster.
Can you put this system on a boat?
Yes see www.sailwings.net/rotaryhome.html
@ethankern
I don't think paddlewheels would work as well. Wern't paddlewheels overtaken by props more than 100 years ago? Just think why that was. The six-speed prop is not a bad idea, but unsuitable for small models. If you have ideas, why don't you make one yourself? It's not too difficult.
Say your turbine is turning 50 rpms and your prop is turning 500rpms because you are using a ratio of 0.9. At this hypothetical moment the wind is pushing the turbine from three points on the rotor at a radius of 100cm. If you change ratios to 0.8 the turbine slows down to 45rpms. The wind will start pushing at three points on the turbine at a smaller radius of 89cm. I am having trouble now because I over simplified. The power coming out of the prop is pushing water. The prop pushes the water from an average radius on the prop. That radius also changes. The only function of the transmission is to control the tip speed of the rotor. Go too slow and it will stall. Really, that is not asinine. That makes the boat safer. I apologize.
This might interest you: th-cam.com/video/wrro4MxNr7Y/w-d-xo.html
It is basically the same thing as you bade but then BIG and its an international race event!
@ethankern
It's just string. Tensioned with jockey pulley and elastic band. with rubber faced pulleys cut into bands from rubber gloves. Goes thro 90 degrees to go back to drive wheel. Check website
Going down wind, would a standard sail be better than the windmill ?
Hydro prop rather.
@ethankern
I meant you could make a small model maybe. Anyway, later you may be able to make one and then you will have all the information. It's all on the website.
@ZKMX7 I would love to make a full sized one but I don't really have access to those kinds of mattereals. And I have a ton more questions. I've just mainly been scribbling things down in a note book. Like what might work and what might not and I really like having someone that's done this before and can say yeah this would work.
It seems to me that if this device would accelerate with a 10 mph wind blowing, then pushing it at 10 mph on a windless day would also accelerate it, in which case you would have perpetual motion, yes?
No, it only works on the difference between windspeed and groundspeed. I'm sure you know that perpetual motion is impossible. You've said it yourself - if you had to push it - you would be putting energy into it and it would not be perpetual motion.
Pete, If the vehicle can accelerate even one kt when it faces a 10 kt wind against its propeller, it must overcome the static coefficient of friction on its wheel bearings, yes? On a windless day, with you pushing it at 10 kts, which produces that same relative wind of 10 kts on the propeller, it only has to overcome the dynamic coefficient of friction in order to accelerate, yes? So with the same relative winds impacting the machine, it should accelerate and leave the 10 kt pushing force behind. Just like pushing a toy cart up a hill, as soon as you reach the top of a hill and the force of gravity then starts accelerating the vehicle, it just wanders ahead of you. The machine does not "know or care" what the wind speed is relative to the ground. It is only concerned with the relative speed against the propeller. That is what makes the propeller turn, yes?
Peter, Surely you can see that if the vehicle accelerates when exposed to a certain velocity of wind, then pushing the vehicle down wind at the same speed would reduce its relative wind to zero and there would be nothing to propel it, even though the wind relative to the ground would remain the same. Can you see then that therefore it is only the relative wind that affects the propeller, not the wind relative to the ground.
Firstly, it is not a propeller it is a wind turbine - a propeller propels (the clue is in the name) whereas a turbine collects and is turned by the wind (the opposite).
The machine certainly, does know the windspeed relative to the ground because the ground is connected to the wheels and the wheels are connected to the turbine. The two are connected. Pushing it into the wind on a windless day does not work. Because the apparent wind over the blades is exactly the same as the speed of the wheels. There is no power available because the 2 mediums are travelling at the same speed. Only when the wind on the blades is MORE than the speed of the wheels will power be produced.
I think you are missing the basic physics here. Newton's first law states that a body in motion tends to stay in motion and a body at rest tends to stay at rest. What that means is in order to set a resting body into motion requires force and likewise a moving body that is acted upon by the same force will accelerate just as the resting body will. So let's consider an ideal frictionless condition and connect your turbine to a variable transmission that can impart torque to the wheels whether they are moving or standing still. If the wind speed of X mph will make the machine at rest accelerate giving it a velocity relative to the wind of X+ε, then the wind created by pushing the machine at the same speed will generate the very same amount of power, which through the transmission will impart the same torque, thus accelerating the vehicle by the same ε mph. Keep in mind that it only takes force to accelerate the machine to X mph and thanks to Newton's first law, no force is required to keep a body in motion that is already in motion. But the wind created by the body that is now in motion, acting on the turbine will create a torque just as it did to the machine when it was at rest. So yes, it takes force to bring the machine up to X mph but once there, it will run by itself forever, in fact accelerate to X+ε. Does that make sense?