Windsails

Windsails are a type of airfoil designed to harness wind power for propulsion. Unlike traditional sails which are rigid or semi-rigid structures, windsails typically consist of flexible material stretched over a supporting frame. This design allows for greater control and adaptability to varying wind conditions. The shape and curvature of the windsail are critical to its efficiency, creating a pressure difference between the two sides that generates lift and thus thrust.

The concept of using flexible, curved surfaces for wind propulsion has roots in early sailing technology, but the modern windsail has seen significant advancements. These advancements often involve lightweight and durable materials, along with sophisticated rigging systems. Windsails are employed in various applications, from recreational sailing and wind-powered vehicles to more experimental forms of renewable energy generation. Their design can be optimized for speed, maneuverability, or maximum power extraction depending on the intended use. The precise angle of attack, or the angle between the windsail and the oncoming wind, is a key factor in controlling the force generated. Adjusting this angle allows sailors or operators to steer and control the speed of the wind-powered craft.