stachu_l wrote: 101pawel wrote: Not only is it not simple, but it is extremely complex.
probably not so much, because the Dutch have been draining their polders for several hundred years and also contributed to the drainage of our Żuławy Wiślane - at least those who threw them out for "bad" faith. Windmills - grain mills are also commonly known.
Normally, I do not engage in such polemics, even in the loose form of Hyde Park, but the thread is unique due to the number of views, so I will write: dear friend, you are wrong, a wind turbine is one of the most complicated technical devices. As far as what you mention, i.e. windmills and other devices with blades acting as propellers, have the only required parameter: they have to rotate, and this rotation does not have to be either efficient or finely calculated. No matter how they spin, the grain will be flour or poured (water will be pumped). As you have not seen in nature, in the pictures, these are quite crude devices, they have not had any improvements for centuries, because they drive something that works well both at 1 rpm and at 100. Only the range of useful rotational speeds mentioned by You can't compare them to what are also called windmills, but the proper name is a wind turbine. A windmill producing electricity uses a certain rotational speed range resulting from the construction of the device itself - including the generator - and anything outside this range could be suitable for grinding flour or pumping water, but not generating en. electricity. Is 2kW in this thread a lot or a little, of course a lot. If the blades of the fan were mounted directly on the shaft of the generator, then at about 1000 rpm, the power of 2kW requires a torque of about 20Nm. It is not little.
stachu_l wrote: I understand that Mr. Czesław Marchaj (https://pl.wikipedia.org/wiki/Czes%C5%82aw_Marchaj) has no followers and the aviation faculties of the university do nothing, our gliders, planes and helicopters were created without aerodynamic knowledge or everyone forgot how it works.
Until I checked - Mr. Marchaj is a late specialist in aerodynamics with achievements in sailing. As for our - Polish contribution to the development of aviation, I do not speak out of my ignorance, but if I wrote about the experiences of wind turbine manufacturers, I quote: "The almost monopolist Vestas still uses nomograms - linking the strength (gusts) of the wind with other parameters, such as seasons , terrain obstacles, altitude above sea level, etc., etc. created over the years by the precursors of the use of wind energy". This is quite different knowledge than aircraft designers have.
As for the windmill from the Syrenka alternator, there are probably thousands of such examples, but does this mean anything? On YT, millions of DIY enthusiasts promote their ideas. Does the fact that one guy in the garage produces drills, the other produces bearings, and the third uses beer cans to cast aluminum rims, does it make sense to produce these products in this way?
. Well, as long as it doesn't hurt anyone. Anyone who has seen a windmill from a distance notices that the propellers spin rather slowly, and in addition with a small range of rotational speed. All this has a purpose, and the overriding one is to achieve the efficiency that allows achieving a reasonable economic result. This cannot be calculated by an amateur, thousands of tests and considerable expenditures are needed for this. This is e.g. there are things to solve. The electrics of the windmill is the simplest problem.
