Editing Propeller (section)

=== Aircraft ===
[[File:Precision air ATR72 5423a.gif|thumb|[[ATR 72]] propeller in flight]]
{{main|Propeller (aeronautics)}}

The [[Wright brothers]] pioneered the twisted [[aerofoil]] shape of modern aircraft propellers. They realized an air propeller was similar to a wing. They verified this using [[wind tunnel]] experiments. They introduced a twist in their blades to keep the angle of attack constant. Their blades were only 5% less efficient than those used 100 years later.<ref>Ash, Robert L., Colin P. Britcher and Kenneth W. Hyde. [https://web.archive.org/web/20110604093014/http://www.memagazine.org/supparch/flight03/propwr/propwr.html "Wrights: How two brothers from Dayton added a new twist to airplane propulsion."] ''Mechanical Engineering: 100 years of Flight'', 3 July 2007.</ref> Understanding of low-speed propeller [[aerodynamics]] was complete by the 1920s, although increased power and smaller diameters added design constraints.<ref>{{cite book |url=http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/ |title=Pilot's Handbook of Aeronautical Knowledge |publisher=U.S. Federal Aviation Administration |year=2008 |location=Oklahoma City |pages=2–7 |id=FAA-8083-25A}}</ref> 

[[Alberto Santos Dumont]], another early pioneer, applied the knowledge he gained from experiences with airships to make a propeller with a steel shaft and aluminium blades for his [[Santos-Dumont 14-bis|14 bis biplane]]. Some of his designs used a bent aluminium sheet for blades, thus creating an airfoil shape. They were heavily [[Camber (aerodynamics)|undercambered]], and this plus the absence of lengthwise twist made them less efficient than the Wright propellers. Even so, this may have been the first use of aluminium in the construction of an airscrew.