Rather hypocritical to accuse me of needing to do research before i post, where you are the one who clearly has done no research at all on the subject.What you say about horizontal axis windmills is only true for small versions like those of the Chinese. You need to prove that the big versions of European windmills, in which the shaft is stuck to a building, could somehow be rotated to face the wind even though the shaft is stuck in place. I asked you for proof of this, and you have yet to give it.
Explain how the fans of this windmill could be rotated 180 degrees to the back of the building:
Show sourcing that such windmills could do what you claim it could do. I asked you already and you have failed to provide, you merely repeated the same-old same-old sourceless claim.
If you had done any research, which you clearly have not, you would know that the entire top rotates 360 degree to face the wind.
Here is a post mill:
On the post mill, you rotate the entire body to turn it into the wind.The Post-Mill Design The psalter picture of 1270 (Figure 1-6), referred to earlier as the first know illustration in a book of a European windmill, shows a mill with a long handle to turn it into the wind; the whole body is mounted on a central post supported by offset struts to the ground. This is known as a post mill, and it is the simplest type of horizontal-axis windmill. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.656.3199&rep=rep1&type=pdf
Anyone who had done any research on all on the subject would know the top of the tower mill rotated.The European windmill’s four sails, possible flat boards in the earliest instances, were mounted on a horizontal shaft, with each sail set at a small angle with respect to the plane of rotation of the whole wheel. This presented several engineering problems. Three major ones were (1) transmission of power from a horizontal rotor shaft to a vertical shaft, on which the grindstones were set; (2) turning the mill into the wind; and (3) stopping the rotor when necessary, because the wind could not be diverted or blocked. The first problem was solved by adopting the cog-and-ring gear shown in Figure 1-5, designed long before by Vitruvius for his horizontal-axis water wheel. To solve the second problem, the bold step was taken of rotating the whole system on a central spindle composed of a stout post supported by heavy beams. This is suggested in Figure 1-6, which is the earliest know representation in a book of this type of windmill and appears as part of an illuminated letter in an English psalter of 1270 [Wailes 1956]. The third problem, stopping the mill, could be solved by turning it out of the wind and applying a frictional braking action at the outer edge of the large gear wheel shown in Figure 1-5.
In order to be able to make larger mills, builders had to take another major inventive step: changing the design from one in which the whole body of the mill had to move to face the wind to one in which only the sails, windshaft, and brake wheel had to move. This was accomplished by mounting the windshaft assembly in the cap of the mill. which turned in a curb or track mounted on the top of a fixed tower. The fact that the mill tower was fixed allowed it to be larger in cross section and higher than the post mill, it could now be made of brick with a circular cross section or of wood in an octagonal shape
Download Limit Exceeded
I think it is clearly inflammatory to accuse someone of ignorance and needing to do research when you are the one who clearly has done NO research on the subject.Again, you bring post-Medieval things in order to make an inflammatory remark. The thread is about who was the most advanced in the Medieval era. Chinese may not know about the spherical earth until after the Medieval period, but Europeans took just as long to recognize that negative numbers were not "absurd numbers". What's your point?
And what is more important, knowing the true shape of the earth and size which has important implications for navigation and calculating astronomical events, allowing others (Persians, Jesuits) to have superior astronomy, or negative numbers which in the middle ages had little practical value?. Exactly what practical value did knowing negative numbers have for the Chinese? And eventually, the Europeans did figure out negative numbers, and did figure out a practical application on their own, while the Chinese did not figure out a spherical earth on their own.
(it would be an interesting topic to find out why the Chinese did not accept a view of a spherical earth on their own, when all their contemporary Old World civilizations did. It isn't a lack of intelligence or skill, but must be deeper. What is it in the Chinese psyche that so resisted the idea of a spherical earth.
And clearly the Persian astronomers at the Ming court did not share the idea of a spherical earth with the Chinese, otherwise Yang Guangxian would not have associated it so strongly with the Jesuits. Was it because their were afraid of the negative reaction and hostility such as Guangxian directed toward the Jesuits? That implies there was some important emotional attachment by the Chinese to the idea of a flat earth. Or was it because the knowledge of a spherical earth gave them a leg up on their Chinese counterparts?. A spherical earth will lead to different predictions of when astronomical events will occur at different locations, such as when an eclipse will occur. The Jesuits were not worried about losing their jobs, they only took the jobs to try to impress the Chinese to win converts. Anyways, Yang Guangxian's actions show that the idea of a spherical earth must not have been held by even a small minority of Chinese scholars before Jesuit contact, otherwise Guangxian could not have been so vocal and fierce in his criticism of the Jesuits if even some Chinese held such views. The very superiority of the Persian and Jesuit astronomers indicate the lack of a spherical view of the Chinese, that is what helped make their astronomy better than the Chinese. Just in case someone tries to argue that perhaps some minority of Chinese held the view.)
I'm not going to apologize for something I've never said. Are you going to apologize for stuffing words into my mouth? If not, show the post number and quote in which I supposedly stated that horizontal axis windmills don't require gearing. [/quotr]
The horizontal axis windmill's don't require gearing, that view is incorrect. The Persian vertical axis windmills often did not have it. You could attach a horizontal beam to the vertical shaft, and put a vertical grinding wheel on it resting on top of the flat mill stone. As the windmill vertical shaft turns, the grinding wheel wiil rotate, much the same way as donkey powered grain mill operates Instead of the donkey turning the vertical shaft and grinding wheel, the wind does it.What I did say was that Chinese vertical axis windmills do require gearing, in response to you saying that they don't.
And why would think that a vertical shaft windmill needs gearing, when a vertical shaft (horizontal wheel) waterwheel doesn't need gearing? It works the same way as the vertical shaft waterwheel, except wind, not water, turns. Once again, you are completely, totally wrong. You correct me, when you are the one that repeatedly doesn't know what he is talking about.
I don't know how much more plain it can be. Once again, as you have been so many times, You were flat out, 100% wrong.Unlike European Don Quixote-style windmills, the Persian design is powered by drag as opposed to lift. And since the blades are arrayed on a vertical axis, energy is translated down the mast to the grindstone without the need for any of the intermediary gears found on horizontal axis windmills. The Ancient Windmills of Nashtifan
I will say this, although I said that you could add gearing to a vertical axis windmill, I didn't think you would. But in that regard I was in error, since the Chinese did add a horizontal power takeout through gearing to their vertical axis windmills. But the Persians did not. But you were completely, 100% wrong about:
1. Horizontal axis windmills couldn't be used in any given wind direction. They could, you just had to turn the windmill, and the medieval horizontal axis windmills were designed to do just that.
2. That vertical axis windmills do need gearing (they don't).
Horizontal axis windmills don't need gearing (they do), but since you said you didn't say it, I let it pass.
To add salt to your would, the picture below shows a vertical axis windmill that automatically adjust to the wind direction. The vane in the rear acts like a weather vane, always ensuring the windmill points into the wind. Wind pushes on the vane, until the vane is parallel to the wind, thus ensuring the windmill points into the wind at all times.