The Coanda Effect:
The Story of Henri Coanda

Henri Coanda was a Romanian engineer, inventor, and aerodynamics pioneer born in 1886. From an early age, he was fascinated by how air moved. After studying engineering in Berlin, Paris, and Liège, he went on to work in aviation, transportation, architecture, and even renewable energy. Over his lifetime, he patented approximately 250 inventions, all focused on the understanding and control of fluids and forces.

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Coanda is best known for designing one of the world’s first jet-propelled aircraft in 1910, the Coanda-1910. This was revolutionary in many ways, as it is now recognised as the first jet-engine aircraft, making its first and only flight in October 1910. However, his achievement went largely unnoticed at the time. Nearly 30 years later, Heinkel, Campini, and Whittle pioneered further jet-engine developments and became known as the “fathers of jet flight,” overshadowing Coanda’s earlier invention, which he did not pursue further.

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Among all of his innovations, the concept that left the greatest mark on modern engineering is the Coanda Effect. Commonly used to this day, the term describes the tendency of a fluid, such as air, to follow the contour of a nearby curved surface rather than move in a straight line. When air is blown along a surface, it “sticks” to it due to pressure differences created by the flow.

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In practical terms, the Coanda Effect helps explain why air clings to the underside of a ceiling, travels along a wall, or stays attached to the inside of a duct. As it remains in contact with the surface, the airstream can travel farther and disperse more smoothly than it would in an open space.

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This effect is especially important in the ventilation industry, where controlling airflow direction and reach is essential. Many modern ducts, grilles, and other ventilation products are engineered to take advantage of the Coanda Effect. By guiding air along ceilings and walls, these products distribute air more evenly, reducing drafts and improving comfort. This helps maintain a consistent temperature throughout the room.

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Henri Coanda’s early curiosity about airflow led to a discovery that transformed how engineers think about air movement. Today, the Coanda Effect plays a vital role not just in aviation but also in ventilation system design, helping create smoother, more efficient airflow in homes and commercial spaces. At Vent Supply, many of the products we offer are built around this very principle. A clear example of how a century-old innovation can still improve efficiency today.