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Propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are specially shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft (ship), propeller shaft with an approximately horizontal axis. History Early developments The principle employed in using a screw propeller is derived from sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Patch
John Patch (1781 – August 27, 1861) was a Nova Scotian fisherman who invented one of the first versions of the screw propeller. Early life Patch was born in Yarmouth, Nova Scotia in 1781. His father Nehemiah was a Yarmouth sea captain who died in a shipwreck at Seal Island, Nova Scotia soon after John Patch's birth. Fishing career Earning a living as a mariner and fishermen, Patch observed the efficiency of small boats propelled by single oar sculling and began to experiment with a propeller based in the motions of a sculling oar. During the winter of 1832-1833 he built a hand-cranked version of a doubled-bladed fan-shaped propeller. He demonstrated his propeller during the summer of 1833 before crowds watching as his small boat moved, seemingly magically, across Yarmouth Harbour. Patch further experimented by attaching his invention to a 25-ton coastal schooner named ''Royal George'' in the Bay of Fundy. The propeller allowed ''Royal George'' to enter Saint John, New Brunswick, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Josef Ressel
Joseph Ludwig Franz Ressel ( cs, Josef Ludvík František Ressel; June 29, 1793 – October 9, 1857) was a forester and inventor of Czech-Austrian descent, who designed one of the first working ship's propellers. Ressel was born in Chrudim, Bohemia then part of the Holy Roman Empire ruled by the Habsburg monarchy, which became part of the Austrian Empire at his death (now the Czech Republic). His father Anton Hermann Ressel was a native German speaker, and his mother Marie Anna Konvičková was a native Czech speaker. He studied at the Linz Gymnasium, Budweis (in today's České Budějovice) artillery school, University of Vienna and the Mariabrunn Forestry Academy at Mariabrunn Monastery then near (now in) Vienna. He worked for the Austrian government as a forester in the more southern parts of the monarchy, including in Motovun, Istria (modern-day Croatia). His work was to secure a supply of quality wood for the Navy.''Josef Ressel. One of the designers of a ship's propel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller Shaft (ship)
A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them. As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, while avoiding too much additional weight as that would in turn increase their inertia. To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or more universal joints, jaw couplings, or rag joints, and sometimes a splined joint or prismatic joint. History The term ''driveshaft'' first appeared during the mid-19th centu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
