Propellers convert engine power into thrust by accelerating a column of air. Even the earliest wooden propellers used by the Wright Brothers were marvels of efficiency and ingenuity. Over time propellers continued to improve. Better materials made them lighter and stronger. Controllable blade pitch made them more versatile and improved performance of the aircraft using them.
|Aeroproducts||Curtiss Electric||de Havilland||Hamilton Standard|
|Hydraulic Governors||Rotol||Woodward Governors|
|American Propeller Co. (1925)||US Army Air Service (1925)||US Army Air Service (1925)||US Army Air Service (1925)||Curtiss P-36 with the first Experimental Curtiss-Electric Four-bladed Controllable-Pitch Propeller (1939)|
Fairey Metal Airscrews (Reed Licence)
Propeller-Related Records at the UK National Archives at Kew --- Compiled by David Birch
An Analysis of the Contra-Rotating Propellers on the 1943 Radioplane OQ-2 Gunnery Target Drone
Early Contra-Prop Videos: Brown B-2 Curtiss P-36