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When talking about a windmill, nowadays we usually refer to that machine used to convert wind energy into mechanical energy.

Looking back in the past, we see that the first practical windmill, that looked quite different than the actual concept of what we nowadays call a windmill, was the vertical axis windmills. They were invented in eastern Persia, somewhere around the 9 th century, even though there are some stories telling that in the 634-644AD this type of machinery was already being used. A similar windmill was used in China in the 13 th century.

The vertical windmill originated in northwestern Europe, more exactly in northern France, eastern England and Flanders, during the late part of the 12 th century. These windmills were used to grind cereals and their particularity was that the whole body was moving, unlike the tower mills that appeared in the 13 th century, and had only a part that was rotating, called the timber cap.

Another windmill type is the smock mill, invented in England, in 1745, and which is a variation of the tower mill. Back then, windmills started to be used for various tasks, like grain grinding, sawmills, threshing, for land drainage or water supply.

Windmills had a very important contribution in allowing the farming and the ranching of vast areas of North America. Also, they were used to expand the rail transport all over the world, as they were pumping water from wells to supply steam locomotives. In Canada, They were part of fortifications. One of the most memorable ones, was the one from Fort Senneville, also called the “most substantial castle-like fort”.

But, with the industrial revolution, the windmill’s place as an energy source was substituted by internal combustion and steam engines. Of course, despite of being an inevitable step in the development of technology, these sources of energy became grave pollutant factors.

That is why, nowadays people tend to come back or to find alternative energies, to stop the damage that toxic gases have brought to our planet. Wind and solar energy are becoming our favorites these days and people are willing to make financial sacrifices in order to make a long term investment that in addition to helping them reduce their energy bills, is 100% ecological.

Much like in other areas, the old-fashioned trends are coming back, and when talking about energy, this is true too. People have begun to realize the harm they have brought to our planet, and try to change this. The good, old windmill is now reborn and ready to help us get the Earth back on feet.

When building windmills, people think about how to increase their efficiency. In order to do that, they analyze the components. The most important components of a windmill are, of course, windmill blades.

The first thing to take into consideration when talking about windmill blades is their number. The more blades a windmill has, the harder will be for it to rotate. The old ones used to have 4 very heavy blades. Most of them were use in grain grinding. Nowadays, the most recent windmills are equipped with two or three blades.

The length is important too. If a blade is longer, it covers a larger surface when it rotates, therefore they can catch more wind with every rotation. This may lead to more torque. To protect the windmill blades we mustn’t forget about their surface. If we provide them with efficient maintenance, they will last longer and will also be more productive.

Also, the shape of windmill blades influences their rotation. There are a few different shapes of windmill blades: the flat, rectangular ones, the wing shaped ones and the ones with both edges tapered to a thin line or both edges rounded like the ones of an airplane wing. In the case of the horizontal axis windmills, the wing shape has proven to be by far the most efficient one. The vertical axis windmills works very well with all the shapes of the windmill’s blades, but the best performance is given by the flat ones and the ones with both edges rounded.

Regarding the material with which the windmill blades are made from, if we think about the old ones, they were usually made from wood. Even though those windmill blades are made of wood, their structure changed over time. They are lighter now so they can spin faster. A common material which brings a high performance due to its sharp edges and its light weight is carbon fiber. Another material that is light, but also cheap is PVC. It is a synthetic material often used for windmill blades. New materials are always being tested, in the hopes of finding a cheaper, more effective solution.

Windmill blades are constantly developing, even though they appeared a very long time ago. At their beginnings they were somehow inefficient, but people learned to develop them and to make the windmills a desirable source of energy. Many more shapes and materials have and will be for windmill blades and people start using more and more this alternative source of energy that will not only save our money, but also our environment.