Leonardo da Vinci sketched an anemometer to estimate wind speed.
His design used a hinged plate that moved with the wind. The stronger the wind, the farther the plate would be pushed, allowing an observer to compare its position with a graduated scale. It was intended as a practical instrument for studying air movement, especially in connection with flying machines.
Leonardo’s anemometer was not a modern cup or propeller anemometer, and it did not produce a digital numerical reading. Instead, it provided a visual indication of wind force. This makes it an early example of a scientific measuring instrument rather than an aircraft itself.
The design is often mentioned alongside Leonardo’s studies of birds, currents, and atmospheric motion. Those investigations helped him connect careful observation with mechanical engineering.