How Did The Panemone Windmill Work?

The Panemone windmill was a type of windmill that was widely used in Europe and North America during the 19th and early 20th centuries. It was designed for grinding grains, pumping water, and milling a variety of raw materials using the power of the wind.

The Panemone windmill had a distinctive dome-shaped cap that allowed it to pivot and turn into the wind. This self-regulating mechanism allowed the blades to catch the wind at the optimum angle for maximum efficiency. The cap sat atop a multi-story brick or wooden tower, which housed all the gears, shafts, and machinery.

The key components of the Panemone windmill included the windshaft, gearbox, fantail, grinding stones, and breaks. The wind blowing on the blades spun the windshaft, which turned a large gearwheel. This transferred power via a series of gears to turn a grinding stone, pump, or other mechanical apparatus. A fantail kept the cap oriented into the wind, while brakes were used to control the speed and power.

How Wind Powered the Panemone

The defining feature of the Panemone windmill was its sails, which captured the wind and translated its force into rotational motion. The sails were large wooden frames covered with lightweight canvas or sailcloth. Their curved aerodynamic shape allowed them to catch the wind from any direction, while the lightweight material reduced drag and enabled the sails to efficiently transform wind energy.
the curved sails of the panemone windmill captured wind energy

Each sail was attached at an angle or “pitch” that enabled it to generate maximum lift and rotation as the wind blew across them. Adjusting the pitch of the sails allowed them to operate in various wind speeds and conditions. The canvas material was stretched tight across the wooden frames to hold its optimal aerodynamic shape.

The sails were mounted on horizontal shafts that were oriented perpendicular to the wind direction. This allowed them to freely rotate and turn into the wind. The shafts were connected to the windshaft inside the windmill, which transferred the rotational force generated by the sails into the grindstones and machinery. The ability of the sails to pivot and rotate with the wind was critical to maximizing the windmill’s efficiency and power output.

Gearbox and Grinding Mechanism

One of the key components of the Panemone windmill was the gearbox, which housed a series of gears and shafts designed to transfer the rotational force of the windshaft down into the millstones or grinding platform. The gearing allowed the windmill to convert the wind energy into useful mechanical energy to drive the grinding process.

The gearbox contained a series of gears in ating down the high rotational speed of the windshaft to the lower speeds needed for the millstones or grinding platform. Often there would be a series of 3-4 sets of gears, progressively reducing the speed further. The gearbox was contained within the windmill housing behind the sails.

Attached to the gearbox was the grinding mechanism itself. In flour mills this consisted of a circular millstone made of granite or similar hard stone. The bottom millstone was fixed in place while the top millstone rotated against it to crush the grain. The gearbox transferred the rotational force to turn the top millstone for grinding. Other types of Panemone windmills used different grinding mechanisms like rollers or hammers to process the raw materials.

Tower and Windshaft

The tower of the Panemone windmill was typically constructed of brick, stone, or wood. It ranged in height from 20 to over 100 feet tall. The height was important to catch stronger winds above structures and trees. Taller towers allowed the windmill to harness more wind power.

Positioned atop the tower was the windshaft, a horizontal shaft pointed into the wind. The windshaft oriented the sails to automatically turn and face the wind. This maximized the rotational power generated. The windshaft was constructed of wood, iron, or steel. It had to be strong enough to support the heavy sails while smoothly rotating with the wind.


One of the key components of the Panemone windmill was the rear fantail. The fantail consisted of a set of vanes mounted perpendicular to the sails on a rear pivot. As the direction of the wind changed, the fantail would turn and orient the windmill so the sails faced into the wind. This maximized the efficiency of the sails in harnessing the wind’s power.

The fantail vanes were connected via gears to the winding shaft that held the main sails. When the wind shifted direction and pushed against the fantail vanes, it would cause the fantail to rotate. This rotation was transferred through the gears to turn the main winding shaft, pivoting the sails to align with the wind.

Early windmills did not have fantails and had to be manually oriented into the wind. The fantail innovation allowed the mills to automatically track changes in wind direction without human intervention. This allowed the windmills to operate unattended for long periods of time, increasing their productivity and efficiency.

The fantail was a simple yet ingenious addition that allowed the Panemone windmill to maximize power generation. By keeping the sails oriented into the wind, it enabled continuous and optimal operation regardless of shifting wind patterns.

Breaks and Safety Features

The Panemone windmill utilized several important breaks and safety features to control the speed of the sails and protect the integrity of the structure during high winds.

The main brake was a rim brake attached to the windshaft just behind the sails. This band brake could be tightened around the axle to slow the rotation of the sails in high winds. Operators would engage the brake to prevent the sails from turning too quickly and causing damage.

There were also aerodynamic brakes built into the backs of the sails themselves. These flaps could be adjusted to reduce the efficiency of the sails by spilling some of the wind. With less wind force acting on the sails, their rotational speed would decrease.

An additional safety feature was the fantail, which turned the windmill out of high winds to prevent damage. If wind speeds became excessive, the fantail would pivot the windmill at right angles to the wind, causing the sails to stop turning.

These braking mechanisms allowed operators to control the speed and protect the Panemone windmill in stormy weather. The breaks were an essential innovation that allowed windmills to extract power from the wind efficiently while safeguarding the machinery.

Efficiency and Power Output

The Panemone windmill was capable of generating a significant amount of power thanks to its unique gearbox design and large sails. With four sails each measuring over 30 feet long, the total sail area exceeded 1,000 square feet. This large sail area allowed the Panemone to capture substantial wind energy.

The gearbox played a critical role in converting the rotary motion of the sails into useful power. It employed a series of wooden gears and shafts that increased the rotational speed coming off the windshaft. This allowed the millstones and other grinding mechanisms powered by the Panemone to operate efficiently. The gearbox design also optimized the torque generated by the sails.

Overall, the Panemone windmill could reliably generate 5-10 horsepower in areas with consistent wind. This level of power output allowed it to grind over 2 tons of grain per hour. For its time, this was an impressive power generation capacity that made the Panemone highly productive and efficient. Its ability to harness wind energy with relatively simple technology was a key factor in its popularity and adoption. The Panemone set the standard for windmill power generation during the 19th century.

Maintenance and Repairs

Windmills like the Panemone required regular maintenance to keep them running efficiently. The moving parts needed frequent lubrication with oil to prevent excessive wear and tear. The gear teeth, in particular, needed greasing on a weekly basis. The fantail and windshaft bearings also needed lubrication to reduce friction.

Another key maintenance task was checking the sails and replacing any cracked or rotted wood. The sails had to be kept in good condition to capture the wind efficiently. Periodic tightening of bolts and screws was also needed to ensure the structural integrity of the entire windmill.

Common repairs included patching holes or leaks in the tower, replacing broken sails or fantail spokes, and fixing worn out brake shoes. Repairs to the grinding stones and bedstone were sometimes required if they became chipped or cracked. More intensive repairs involved lifting the cap of the windmill to access and fix damaged gears or shafts inside the gearbox.

Keeping the Panemone windmill well maintained took regular effort, but was critical to keeping it running smoothly for decades. Skilled windmillers climbed the towers frequently to check for any issues needing repair.

Demise of the Panemone Windmill

The Panemone windmill began to fall out of favor in the early 20th century with the advent of cheap electricity and improvements in power generation technology. While windmills like the Panemone had been a vital source of mechanical power for centuries, the increasing affordability and reliability of electric motors led many windmill owners to switch over.

One of the main downfalls of the traditional Panemone design was its inability to generate electricity directly. The grinding and pumping applications were still useful in rural areas, but the growing demand was for electric power to light homes and businesses. This transition spelled trouble for windmill manufacturers who were slow to adapt and design electrical generating windmills.

By the 1920s and 30s, many Panemone style windmills were being decommissioned or left to deteriorate. The growing electrical grids and cheap oil made small scale wind power obsolete in the eyes of most people. While some windmills limped on into the 1950s, by then the technology was clearly antiquated and liability concerns led owners to demolish the remaining towers. Within a couple decades, the Panemone design had all but vanished from the landscape.

Though rendered obsolete, the legacy of the Panemone windmill lived on through its contributions to mechanical engineering and the later resurgence of wind power. The demise of this particular design opened new doors to more advanced wind harnessing applications that would one day help revive wind as a viable energy source.

Legacy and Significance

The Panemone windmill left behind an impressive legacy and made important contributions to the development of wind power technology. At its peak in the late 19th and early 20th centuries, the Panemone design was one of the most popular and widely used windmills. Thousands were constructed worldwide to harness the power of wind for pumping water and milling grain.

The Panemone made significant advancements in windmill automation. Its self-regulating design allowed it to automatically turn to face the wind and adjust the amount of sail surface needed. This increased efficiency and allowed the mills to operate unattended. The Panemone’s lightweight yet durable wood and steel construction also represented a major advancement in engineering and materials science.

Today, the principles behind the Panemone windmill are still influencing modern wind turbine designs. The automated self-regulation system allows turbines to actively position themselves for optimal wind exposure. The aerodynamic wooden blades have evolved into today’s advanced composite materials that capture more wind energy. Although the Panemone windmills are no longer used, their pioneering legacy lives on in modern renewable energy solutions.

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