2000 years B.C.

14. Century

The following pictures were drawn and send by: Dr. Ulrich Alertz RWTH Aachen, Germany
Historisches Institut, Lehrstuhl für Mittlere Geschichte.

The so called "Windwagen" by Guido von Vigevano.
That people can drive directly into the wind, this was prooved already in the middleage, some hundred years ago. There exists a copy from an old manuscrict of Guido von Vigevano of the year 1335, the "Texaurus (treasure) regis francie" which shows the construction of a windcart used for military purposes probably.
Guido was italian and technically well versed. He was court-physician of the french king Philipp VI. The dimensionen of the carriage-wheels: roughly 2,4 m diameter. Diameter of the 4 bladed windmillrotor roughly 6-8 Meter. Output of the system some kilowatts. With this energy experts mean that the cart could reach nearly 30 mph, directly into the wind.

16. Century

The Dutch are besides the Danish and the German the "Wind Nation Number One" in Europe in the Middle Ages.

Around 1900

Around the turn of the century, it was the time of the so called "western mills", the multibladed metal sheet rotors, the slow running windturbines, especially for the purposes of water pumping. The starting torque of these machines is pretty good high.

1932

Hermann Honnef proposed in den thirties the idea of huge contrarotating rotors with ringgenerators built-in. Rotor and "stator" of the elektric machine belong equally corresponding to one of the contrarotating multibladed rotors. The diameter of the ringgenerator reached 120 meter, the diameter totally was 160 meter. The output of this giant should be 20 MW at a windspeed of 15 m/s. The projekt remained only a paper study.
Nevertheless, Honnef is an important pioneer of windenergy utilization. He proposed early, as first, the"offshore"-technic for windenergy converters.
His plant was installed offshore, floating on a anchored pontoon, harvesting the wind circular, like a grasseating sheep pinned by a rope to a peg. The pontoon takes always the right position, floating downstream away.

1942

This year pass for the starting point of modern wind energy utilization. Ulrich Hütter finished as assistent professor at the "Ingenieurschule Weimar" his masters thesis: "Beitrag zur Schaffung von Gestaltungsgrundlagen für die Windkraftwerke", which means: Creation of rules for the layout of wind energy converters. In this thesis he wrote down the theoretic basics for all modern free- and highspeedrunning turbines (in german: "Freifahrende schnellaufende Turbinen"), with 2 or 3 rotorblades.
His blade-element-momentum-theory, developed with excellent aeronautical knowledge, is even today current. His theory can be learned by the students in lectures at the University of Stuttgart as optional lecture.

1942

In world war II, in the years 1941 to 1945, on the hill called Grandpa's Knob, nearby Rutland,
state Vermont, USA, 330 km northward of New York, there was erected a 1250 kW wind energy converter, build by Smith/Putnam, two famous designing engineers.
Diameter of the plant 53,23 meter, height of tower 32,6 meter, rotorshaft diameter 610 mm. Each of the two rotorblades, material steel, has had a mass of 8 tons. 1942 accured an accident. In a heavy storm the plant loosed one blade. It flew away and was found more than 230 Meter aside the tower. In the year 1945 this pilot plant was shut down.

doerner@ifb.uni-stuttgart.de Since 24th mars 1997, updated continuously