The Wright brothers were the first to design propellers as rotating wings rather than screws.

In 1902 and 1903, Orville and Wilbur Wright conducted pioneering research that changed aviation history. While contemporary engineers like Samuel Langley viewed propellers as 'marine screws' meant to push through a medium, the Wrights used their wind tunnel data to prove that a propeller is actually a lift-generating wing. They realized that every section of the blade should be shaped like an airfoil to create aerodynamic lift in a forward direction.Using their custom-built wind tunnel in Dayton, Ohio, they tested various blade shapes and pitches. They eventually settled on a design made of two layers of spruce wood glued together and shaped with a hatchet and drawknife. Their final 1903 propeller design was remarkably advanced for its time, achieving an efficiency rating of approximately 66%.This efficiency was critical because their purpose-built four-cylinder engine produced only about 12 horsepower. Without the high thrust-to-weight ratio provided by their 'rotating wing' theory, the Wright Flyer would have been too heavy to leave the ground. Modern wooden propellers often achieve about 80% efficiency, which highlights how sophisticated the Wrights' original 1903 calculations truly were.Their findings were so revolutionary that they initially kept the details secret to protect their patents. It wasn't until their public demonstrations in 1908 that the rest of the scientific community fully grasped the importance of the airfoil-shaped propeller. Today, this principle remains the fundamental basis for all propeller-driven aircraft and even wind turbine blades.