China may have been the birthplace of the windmill. The earliest actual documentation of a Chinese windmill was in 1219 A.D. by the Chinese statesman Yehlu Chhu-Tshai. It is assumed to have been used primarily for grain grinding and water pumping.

A vertical axis system called panemone device was developed in Persia about 500-900 A.D. It was apparently used for water pumping. The first document design features vertical sails made of bundles of reeds or wood which were attached to the central vertical shaft by horizontal struts.

Grain grinding windmills consisted of a grinding stone affixed to a vertical shaft driven by a horizontally mounted wind rotor. The mill machinery was commonly enclosed in a building. Wooden cog-and-ring gears were utilized for the vertical axis rotor to drive the horizontal axis grindstone.

Rotor designs have their roots in sailboat design from which early knowledge of wind forces was learned by experimentation. On the island of Crete sail-rotor windmills are still used to pump water. Steel bladed versions of these pumps were used through out the American heartland in the late 1800's. By 1970 over six million small windmills were installed in the U.S. primarily for pumping water. Raised water towers were a common storage method that provided on demand water pressure delivery. By the mid-1920's Parris-Dunn and Jacobs were major suppliers for wind-electric to the mid-west and Great Plains area. The early success of the Midwest wind turbines actually set the stage for the possibility of more extensive wind energy development in the future.

The development of bulk-power, utility-scale wind energy conversion systems was first undertaken in Russia in 1931 and operated for two years on the Caspian Sea. Experimental wind plants were tried in US and Europe from 1935 until 1970 but failed to be practical.

http://energysourcefacts.org/

As with all modern scientific and technological endeavors, computers, software and internet tools play an increasingly important role. As well as the typical business application software there are a number of computer aided applications specifically for engineering. Computers can be used to generate models of fundamental physical processes, which can be solved using numerical methods.

A number of decisions have to be made which directly affect the product's overall and total cost. One of the first decisions that has to be made deals with the initial design. At one time, engineers had to convert from manual design and drafting on a drawing board to 2D CAD. Now we are starting to see a new shift in the field cad design. Within the past decade, the engineering, design and drafting world has been experiencing a shift from 2d to 3d cad. Many inventors and companies still use 2d drawings and are starting to realize the benefit of skipping the 2d step and starting off with a 3d design because 3d modeling can save time and money as well as improve customer relations. This article will explain why inventors should take 3d cad into strong consideration.

These types of transitions occur from time to time and are completely normal. Many engineers will argue with these facts because only about 50% of the engineers out there use 3d modeling software, but the fact still remains that 3d cad models can save time and money in the long run and there are many facts that prove that the assumption that the use of 2d cad drawings is inexpensive is simply a myth.

The truth is that making 2d drawings is fast and easy, but the output is still a 2D drawing, which does not readily work with downstream systems like purchasing and manufacturing. In some cases 2d drawings are sufficient but 90% of the time they are not. In prototyping, for example, a 3d model has to be made because most of the prototyping machines require 3d data. In fact, the majority of the machines used to manufacture parts need 3d cad files and do not read 2d cad drawings because 2d drawings do not contain all information needed to develop a three-dimensional product. http://cadmodels.info/