Architecture

Some people tend to think that, regardless of their function, all four-sailed windmills must be Dutch. Although the Dutch erected thousands of windmills and undoubtedly revolutionized wind powered machines as we know them, not all windmills are exactly the same or can be called “Dutch.”

Custom windmills in Illinois are also influenced by styles and technology developed throughout Europe. The following demonstrates how windmill architecture differs between different regions of the world.

Netherlands

Dutch windmills come in all shapes and sizes, from tiny tjaskers that irrigate small fields to stage tower mills for industrial use. There is no single windmill that could possibly represent all of the different types in the Netherlands.

The Dutch are probably best known simply for the sheer number of windmills they constructed. They were forced to rely on the wind because of their lack of other natural resources (such as coal or wood) from which they could operate steam engines or fuel power plants. For this reason, over 9,000 windmills operated at the peak of the Industrial Revolution; over 1,150 of these are still operating today, and more are being restored to operating condition.

Because Dutch windmills are among the largest, most powerful, and advanced of all custom windmills, their design was copied by millwrights all over the world. Dutch mills were the first to have inclined sails (by about 12 degrees) to account for stronger winds at higher altitudes. They were the first to construct tower mills with pivoting caps (rather than turning the entire mill into the wind). Typical sails have a tapering angle of weather and provide a lattice framework for the miller to adjust the sailcloth.

Iconic Dutch stage and tower mills are constructed as octagonal prisms that taper in diameter near the top. At the base of the tower is a “skirt,” designed to lead rainwater away from the sill plate. The caps of Dutch windmills are oddly shaped—often described as an “inverted boat”—and covered in reed thatch (never shingles).

Windmills in this region have very little ironwork aside from the quants and the wind shafts. Many are also brightly painted red, white, and blue (the nation’s colors). The “beard,” located just beneath the front of the cap, signifies the construction date and the mill’s name (a requirement by traditional Dutch law). The vast majority of windmills here are luffed manually via a tail pole, rather than with a tail fan.

Germany

The Germans adapted windmill designs from across Europe. The oldest windmills still standing are cylindrical stone tower mills akin to those found on the Mediterranean coast. Some wooden post mills were clearly modeled after those in England and France at the time, although later the Germans built the largest post mills in the world: in Saxony, the mills’ upper bodies are three or four-floor structures.

To the average tourist, the newer tower and stage mills patterned after the Dutch appear the same; however, the towers of German mills tend to have a wider octagonal base with a much more pronounced skirt (in fact, the cant posts, located at the corners of the octagon, are constructed to curve with the skirt to accommodate the larger diameter base). Nearly all of the stage mills here are automatically luffed via tail fans and use patent sails, where the Dutch prefer the traditional, manual methods.

Belgium

Belgians also borrowed Dutch sail and mechanical designs, but the windmills in Belgium are primarily slender stone or brick cylindrical beltmolens. These mills are manually luffed and their towers are painted white. Very few tower mills here are octagonal or wooden, aside from the large post mills that survived.

Compared to other countries, the windmills of Belgium are of newer construction; post mills were constructed in the late 1700s and early 1800s. The beltmolens and tower mills constructed in the 1850s and 60s usually have metal sail stocks and are equipped with newer milling equipment.

United Kingdom

Like the Dutch, English mills come in all types, from tiny post mills to huge brick tower mills. Custom windmills of new and old construction employ a number of important English contributions to wind technology, including the tail fan, angle of weather, patent shutter sails (in fact, traditional cloth sails are virtually nonexistent), and building mills with more than four sails.

Although some windmills date to the 1200s or prior, many have been retrofit with new caps, sails, and equipment as needed. Remnants of tower mills are still attached to more modern factories that now operate on electricity. Others have been converted into lighthouses, homes, condominiums, or restaurants.

Aside from the technological improvements, English tower mills tend to sport simple domed caps. The tallest mills are made of brick and are located in populated areas; smaller wooden mills dot the rural landscape. Stone tower mills that survived are found near the coasts and in various locations across the nation.

France

Nearly all French windmills follow the same distinct architectural form. Every tower mill, large or small, is perfectly cylindrical in shape and has a tall, wooden, conical cap. Surprisingly, the majority of windmills operate with four traditional double-sided sails and are manually luffed by a large wooden tail pole that extends from the cap at about a 30 degree angle.

The French were among the first to construct simple post mills for light-duty grinding purposes. Before the 1800s, French post mills were usually just a few stories tall with sail spans no more than twenty feet. Over time they became larger to accommodate more equipment for industrial use.

Few mills in France are equipped with the technological innovations of the English, but a handful operates with Berton-style sails. Beginning in 1848, some tower mills were retrofit with sails with vertical slats that automatically cascade depending on wind conditions. When not in use, the sails collapse to the width of the sail stock.

Mediterranean Coast

Greece/Italy/Portugal/Spain/Turkey

Windmills located directly on the shore of the Mediterranean Sea were the first wind-powered machines in Europe. Not surprisingly, these windmills share the same architectural style. Their stone towers are completely cylindrical in shape and are large enough to accommodate grinding equipment.

Because the wind primarily blows in from the sea, the caps do not require luffing; thus, there are no tail poles to speak of. The conical caps are often finished in thatch.

All of the tower mills originally operated with jib sails. This required miller to reef the sails just as a sailor would on a boat; these sails appear more like sailboat masts fixed to a rotating shaft. When fully rigged, these windmills appear as large, white pinwheels.

Tower mills still standing in these countries (especially those found further inland) have been retrofit with movable caps and modern sails. Perhaps the most popular of these mills are found in La Mancha, Spain, made famous by Cervantes’ Don Quixote.

Southeast Europe

Bulgaria/Romania/Slovakia/Ukraine

Few windmills still exist in this region of Europe, but their architecture provides an all-important link in the evolution of windmill design. Like other European nations, the first windmills constructed here were stone tower mills equipped with jib sails, built like those found along the Mediterranean.

When post mills were being constructed here, however, lattice-framed sails were not used; instead, these “hybrid” post mills continued operating with jib sails, and had foundations of stone. In fact, these may be the only such examples in existence. Larger wooden post mills were eventually built using double-sided panel sails common to Eastern Europe. There are no definitive examples of Dutch-influenced windmills in these areas.

Russia

There is little doubt Russia took advantage of its great natural timber resources when constructing their windmills. Both post and tower mills here are made of wood; there are no stone mills to speak of. Post mills resemble log cabins more than anything: they are made of whole logs (including the wind shaft and sail stocks) varying in size and in number of sails. It is not uncommon to see four, six, and eight sail windmills here.

The sail stocks are so heavy that some have logs supporting the neck of the wind shaft. The double-sided panel sails can be accessed by a wooden ladder (rather than climbing the sails, as on Dutch mills). There are no definitive examples of Dutch-influenced windmills in Russia.

Poland

Poland features an interesting blend of architectural elements in their windmills. Stone tower mills that were first constructed were typical of those found along the Mediterranean, but late the towers were built with a sloped profile. The Polish also constructed wooden post mills much like those in Germany. Tower mills built during the Industrial revolution borrowed the traditional Dutch design, except using wooden panels and shingles instead of reed thatch.

Polish windmill sails also originate from mixed styles. Double-sided panel sails are present on the older mills, and traditional Dutch sails are used on Dutch-style windmills. A few of the smaller wooden mills catch the wind with annular sails.

Northern Europe

Denmark/Estonia/Finland/Latvia/Lithuania/Norway/Sweden

Early post mills in this region vary in architecture, borrowing the English and Southeastern European designs. These small wooden mills operate with double-sided panel sails, many of which still stand.

The tower mills here were influenced by the Dutch and Germans. The framework and sails of most mills are very similar to those found south; however, the towers are smaller in overall width than the Dutch, and the skirts of smock mills are not as apparent (just as they appear on the Fabyan and Fischer windmills).

Although Dutch sails are prevalent here, patent sails—and, particularly, double-sided shutter sails—are used, as present on the Danish Windmill in Iowa. Cross-framing can typically be seen in the window panes and between handrail posts of the stage. The single distinguishing characteristic is the design of the cap, which is primarily round but comes to a point at the center to allow clearance for the brake wheel and band brake.

United States

The United States probably had thousands of windmills operating in its early years; sadly, few have survived. Because Chicago served as a major, centralized railroad hub, Illinois once had among the greatest concentration of custom windmills in operation.

Post mills and small tower mills were built by the English in the thirteen colonies and by the French in what is now the Midwest. The Dutch, who settled in New England, New York, and Pennsylvania, constructed smock mills. But because the Northeast is home to several streams, water-power mills were greater in number.

When the Germans settled in Illinois in the 1800s, they constructed great custom smock windmills throughout the state. These were all among the largest of their kind at the time, and together produced hundreds of barrels of flour, meal, bran, and feed every day. Every millwright constructed their mill differently: there are elements of Dutch, German, Belgian, English, French, Swedish, and Danish architecture present in the mills still standing today.