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Propellers
A propeller (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 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 stern sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the blade to the wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship
A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity and purpose. Ships have supported Geographic exploration, exploration, Global trade, trade, Naval warfare, warfare, Human migration, migration, colonization, and science. Ship transport is responsible for the largest portion of world commerce. The word ''ship'' has meant, depending on the era and the context, either just a large vessel or specifically a Full-rigged ship, ship-rigged sailing ship with three or more masts, each of which is Square rig, square-rigged. The earliest historical evidence of boats is found in Egypt during the 4th millennium BCE. In 2024, ships had a global cargo capacity of 2.4 billion tons, with the three largest classes being ships carrying dry bulk (43%), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-blade Propeller
A single-blade propeller may be used on aircraft to generate thrust. Normally propellers are multi-blades but the simplicity of a single-blade propeller fits well on motorized gliders, because it permits the design of a smaller aperture of the glider fuselage for retraction of the power plant. The counterbalanced teetering mono-blade propeller generates fewer vibrations than conventional multi-blade configurations. Often, single blade propeller configurations are touted as having a much greater efficiency than multi-blade propellers, but this is a falsehood outside the inertial losses in spinning a heavier propeller, and the minimal additional drag from added blades. Single bladed propellers are principally used to fulfill engineering requirements that fall outside the scope of efficiency. Patents US Patent 2742095 Mechanism for balancing single blade aircraft rotorUS Patent 6619585 Helicopter single-blade rotorUS Patent 5971322- Propeller propulsion unit for aircraft in gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, in a few cases, direct Powered lift, downward thrust from its engines. Common examples of aircraft include airplanes, rotorcraft (including helicopters), airships (including blimps), Glider (aircraft), gliders, Powered paragliding, paramotors, and hot air balloons. Part 1 (Definitions and Abbreviations) of Subchapter A of Chapter I of Title 14 of the U. S. Code of Federal Regulations states that aircraft "means a device that is used or intended to be used for flight in the air." The human activity that surrounds aircraft is called ''aviation''. The science of aviation, including designing and building aircraft, is called ''aeronautics.'' Aircrew, Crewed aircraft are flown by an onboard Aircraft pilot, pilot, whereas unmanned aerial vehicles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that system. The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. In mechanical engineering, force orthogonal to the main load (such as in parallel helical gears) is referred to as static thrust. Examples A fixed-wing aircraft propulsion system generates forward thrust when air is pushed in the direction opposite to flight. This can be done by different means such as the spinning blades of a propeller, the propelling jet of a jet engine, or by ejecting hot gases f ... [...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, 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 ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archimedes' Screw
The Archimedes' screw, also known as the Archimedean screw, hydrodynamic screw, water screw or Egyptian screw, is one of the earliest documented hydraulic machines. It was so-named after the Greek mathematician Archimedes who first described it around 234 BC, although the device had been developed in Egypt earlier in the century. It is a reversible hydraulic machine that can be operated both as a pump or a power generator. As a machine used for lifting water from a low-lying body of water into irrigation ditches, water is lifted by turning a screw-shaped surface inside a pipe. In the modern world, Archimedes screw pumps are widely used in wastewater treatment plants and for dewatering low-lying regions. Run in reverse, Archimedes screw turbines act as a new form of small hydroelectric powerplant that can be applied even in low head sites. Such generators operate in a wide range of flows (0.01 m^3/s to 14.5 m^3/s) and heads (0.1 m to 10 m), including low heads and moderate flow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bamboo-copter
The bamboo-copter, also known as the bamboo dragonfly or Chinese top ( Chinese ''zhuqingting'' (竹蜻蜓), Japanese ''taketonbo'' ), is a toy helicopter rotor that flies up when its shaft is rapidly spun. This helicopter-like top originated in Jin dynasty China around 320 AD, and was the object of early experiments by English engineer George Cayley, the inventor of modern aeronautics.Leishman, J. Gordon (2006)''Principles of Helicopter Aerodynamics'' Cambridge University Press. pp. 7–9. In China, the earliest known flying toys consisted of feathers at the end of a stick, which was rapidly spun between the hands and released into flight. "While the Chinese top was no more than a toy, it is perhaps the first tangible device of what we may understand as a helicopter." The Jin dynasty Daoist philosopher Ge Hong's (c. 317) book '' Baopuzi'' (抱樸子 "Master Who Embraces Simplicity") mentioned a flying vehicle in what Joseph Needham calls "truly an astonishing passage".J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archimedes Screw
The Archimedes' screw, also known as the Archimedean screw, hydrodynamic screw, water screw or Egyptian screw, is one of the earliest documented hydraulic machines. It was so-named after the Greek mathematician Archimedes who first described it around 234 BC, although the device had been developed in Egypt earlier in the century. It is a reversible hydraulic machine that can be operated both as a pump or a power generator. As a machine used for lifting water from a low-lying body of water into irrigation ditches, water is lifted by turning a screw-shaped surface inside a pipe. In the modern world, Archimedes screw pumps are widely used in wastewater treatment plants and for dewatering low-lying regions. Run in reverse, Archimedes screw turbines act as a new form of small hydroelectric powerplant that can be applied even in low head sites. Such generators operate in a wide range of flows (0.01 m^3/s to 14.5 m^3/s) and heads (0.1 m to 10 m), including low heads and moderate flow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egyptians
Egyptians (, ; , ; ) are an ethnic group native to the Nile, Nile Valley in Egypt. Egyptian identity is closely tied to Geography of Egypt, geography. The population is concentrated in the Nile Valley, a small strip of cultivable land stretching from the Cataracts of the Nile, First Cataract to the Mediterranean Basin, Mediterranean and enclosed by desert both to the Eastern Desert, east and to the Western Desert (North Africa), west. This unique geography has been the basis of the DNA history of Egypt, development of Egyptian society since Ancient Egypt, antiquity. The daily language of the Egyptians is a continuum of the local variety of Arabic, varieties of Arabic; the most famous dialect is known as Egyptian Arabic or ''Masri''. Additionally, a sizable minority of Egyptians living in Upper Egypt speak Sa'idi Arabic. Egyptians are predominantly adherents of Sunni Islam with a small Shia minority and a significant proportion who follow native Sufi tariqah, orders.Hoffman, Val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Hooke
Robert Hooke (; 18 July 16353 March 1703) was an English polymath who was active as a physicist ("natural philosopher"), astronomer, geologist, meteorologist, and architect. He is credited as one of the first scientists to investigate living things at microscopic scale in 1665, using a compound microscope that he designed. Hooke was an impoverished scientific inquirer in young adulthood who went on to become one of the most important scientists of his time. After the Great Fire of London in 1666, Hooke (as a surveyor and architect) attained wealth and esteem by performing more than half of the Boundary (real estate), property line surveys and assisting with the city's rapid reconstruction. Often vilified by writers in the centuries after his death, his reputation was restored at the end of the twentieth century and he has been called "England's Leonardo da Vinci, Leonardo [da Vinci]". Hooke was a Fellow of the Royal Society and from 1662, he was its first Curator of Experimen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Haven, Connecticut
New Haven is a city of the U.S. state of Connecticut. It is located on New Haven Harbor on the northern shore of Long Island Sound. With a population of 135,081 as determined by the 2020 United States census, 2020 U.S. census, New Haven is List of municipalities in Connecticut, the third largest city in Connecticut after Bridgeport, Connecticut, Bridgeport and Stamford, Connecticut, Stamford, the largest city in the South Central Connecticut Planning Region, Connecticut, South Central Connecticut Planning Region, and the principal municipality of Greater New Haven metropolitan area, which had a total population of 864,835 in 2020. New Haven was one of the first Planned community, planned cities in the U.S. A year after its founding by English Puritans in 1638, eight streets were laid out in a four-by-four Grid plan, grid, creating the "Nine Square Plan". The central common block is New Haven Green, the New Haven Green, a square at the center of Downtown New Haven. The Green is n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
