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Rudder
A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane. A rudder operates by redirecting the fluid past the hull or fuselage, thus imparting a turning or yawing motion to the craft. In basic form, a rudder is a flat plane or sheet of material attached with hinges to the craft's stern, tail, or after end. Often rudders are shaped so as to minimize hydrodynamic or aerodynamic drag. On simple watercraft, a tiller—essentially, a stick or pole acting as a lever arm—may be attached to the top of the rudder to allow it to be turned by a helmsman. In larger vessels, cables, pushrods, or hydraulics may be used to link rudders to steering wheels. In typical aircraft, the rudder is operated by pedals via mechanical li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiller
A tiller or till is a lever used to steer a vehicle. The mechanism is primarily used in watercraft, where it is attached to an outboard motor, rudder post or stock to provide leverage in the form of torque for the helmsman to turn the rudder. A tiller may also be used in vehicles outside of water, and was seen in early automobiles. On vessels, a tiller can be used by the helmsman directly pulling or pushing it, but it may also be moved remotely using tiller lines or a ship's wheel. Rapid or excessive movement of the tiller results in an increase in drag and will result in braking or slowing the boat. Description A tiller is a lever used to steer a vehicle. It provides leverage in the form of torque to turn the device that changes the direction of the vehicle, such as a rudder on a watercraft or the surface wheels on a wheeled vehicle. A tiller can be used by directly pulling or pushing it, but it may also be moved remotely using tiller lines or a ship's wheel; some kayak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship
A ship is a large watercraft that travels the world's oceans and other sufficiently deep 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 exploration, trade, warfare, migration, colonization, and science. After the 15th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to world population growth. 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 ship-rigged sailing ship with three or more masts, each of which is square-rigged. As of 2016, there were more than 49,000 merchant ships, totaling almost 1.8 billion dead weight tons. Of these 28% were oil tankers, 43% were bulk carriers, and 13% w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Lefebvre Des Noëttes
Richard Lefebvre des Noëttes (1856–1936) was a French officer and early historian of technology. After his early retirement from the French army in 1901, Lefebvre devoted his time to technological studies, then quite a new field, becoming a main proponent of the negative impact of slavery on technological progress in classical antiquity. Although dissenting voices emerged as early as the 1930s, his primitivist views of ancient traction technology met with considerable success in the 1950s and 1960s when authorities like the medievalist Lynn White and the sinologist Joseph Needham, but also many classicists, relied rather uncritically on his research. Based on a thorough reexamination of the pictorial evidence, much of it not available in Lefebvre's time, as well as experimental archaeology, modern scholars like Georges Raepsaet have refuted Lefebvre's findings, particularly his glaring underestimation of the capacities of ancient horse-drawn ploughs and carriages. His depreciatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adverse Yaw
Adverse yaw is the natural and undesirable tendency for an aircraft to yaw in the opposite direction of a roll. It is caused by the difference in lift and drag of each wing. The effect can be greatly minimized with ailerons deliberately designed to create drag when deflected upward and/or mechanisms which automatically apply some amount of coordinated rudder. As the major causes of adverse yaw vary with lift, any fixed-ratio mechanism will fail to fully solve the problem across all flight conditions and thus any manually operated aircraft will require some amount of rudder input from the pilot in order to maintain coordinated flight. History Adverse yaw was first experienced by the Wright brothers when they were unable to perform controlled turns in their 1901 glider which had no vertical control surface. Orville Wright later described the glider's lack of directional control. Causes Adverse yaw is a secondary effect of the inclination of the lift vectors on the wing due to its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helmsman
A helmsman or helm (sometimes driver) is a person who steers a ship, sailboat, submarine, other type of maritime vessel, or spacecraft. The rank and seniority of the helmsman may vary: on small vessels such as fishing vessels and yachts, the functions of the helmsman are combined with that of the skipper; on larger vessels, there is a separate officer of the watch who is responsible for the safe navigation of the ship and gives orders to the helmsman, who physically steers the ship in accordance with those orders. In the merchant navy, the person at the helm is usually an able seaman, particularly during ship arrivals, departures, and while maneuvering in restricted waters or other conditions requiring precise steering. An ordinary seaman is commonly restricted to steering in open waters. Moreover, military ships may have a seaman or quartermaster at the helm. A professional helmsman maintains a steady course, properly executes all rudder orders, and communicates to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoenicia
Phoenicia () was an ancient thalassocratic civilization originating in the Levant region of the eastern Mediterranean, primarily located in modern Lebanon. The territory of the Phoenician city-states extended and shrank throughout their history, and they possessed several enclaves such as Arwad and Tell Sukas (modern Syria). The core region in which the Phoenician culture developed and thrived stretched from Tripoli and Byblos in northern Lebanon to Mount Carmel in modern Israel. At their height, the Phoenician possessions in the Eastern Mediterranean stretched from the Orontes River mouth to Ashkelon. Beyond its homeland, the Phoenician civilization extended to the Mediterranean from Cyprus to the Iberian Peninsula. The Phoenicians were a Semitic-speaking people of somewhat unknown origin who emerged in the Levant around 3000 BC. The term ''Phoenicia'' is an ancient Greek exonym that most likely described one of their most famous exports, a dye also known as Tyria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of China
The earliest known written records of the history of China date from as early as 1250 BC, from the Shang dynasty (c. 1600–1046 BC), during the reign of king Wu Ding. Ancient historical texts such as the ''Book of Documents'' (early chapters, 11th century BC), the ''Bamboo Annals'' (c. 296 BC) and the ''Records of the Grand Historian'' (c. 91 BC) describe a Xia dynasty before the Shang, but no writing is known from the period, and Oracle Bone script, Shang writings do not indicate the existence of the Xia. The Shang ruled in the Yellow River valley, which is commonly held to be the cradle of Chinese civilization. However, Neolithic civilizations originated at various cultural centers along both the Yellow River and Yangtze, Yangtze River. These Yellow river civilization, Yellow River and Yangtze civilizations arose millennia before the Shang. With thousands of years of continuous history, China is among the world's oldest civilizations and is regarded as one of the Cradle of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Needham
Noel Joseph Terence Montgomery Needham (; 9 December 1900 – 24 March 1995) was a British biochemist, historian of science and sinologist known for his scientific research and writing on the history of Chinese science and technology, initiating publication of the multivolume '' Science and Civilisation in China''. He was elected a fellow of the Royal Society in 1941 and a fellow of the British Academy in 1971. In 1992, Queen Elizabeth II conferred on him the Companionship of Honour, and the Royal Society noted he was the only living person to hold these three titles. Early life Needham's father, Joseph was a doctor, and his mother, Alicia Adelaïde, née Montgomery (1863–1945), was a music composer from Oldcastle, County Meath, Ireland. His father, born in East London, then a poor section of town, rose to became a Harley Street physician, but frequently battled with Needham's mother. The young Needham often mediated. In his early teens, he was taken to hear the Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxford Dictionary Of English Etymology
''The Oxford Dictionary of English Etymology'' is an etymological dictionary of the English language, published by Oxford University Press. The first editor of the dictionary was Charles Talbut Onions, who spent his last twenty years largely devoted to completing the first edition, published in 1966, which treated over 38,000 words and went to press just before his death. Editions *C. T. Onions, ed.; edited by C. T. Onions with the assistance of G. W. S. Friedrichsen and R. W. Burchfield (1966, reprinted 1983, 1992, 1994) Also published by OUP: *''The Concise Oxford Dictionary of English language'' **T. F. Hoad (1986) **T. F. Hoad (1993) *''An Etymological Dictionary of the English Language'' **W. W. Skeat (1910; reprint 1963; now in the public domain) See also * ''Oxford English Dictionary The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encyclopædia Britannica
The (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various times through the centuries. The encyclopaedia is maintained by about 100 full-time editors and more than 4,000 contributors. The 2010 version of the 15th edition, which spans 32 volumes and 32,640 pages, was the last printed edition. Since 2016, it has been published exclusively as an online encyclopaedia. Printed for 244 years, the ''Britannica'' was the longest running in-print encyclopaedia in the English language. It was first published between 1768 and 1771 in the Scottish capital of Edinburgh, as three volumes. The encyclopaedia grew in size: the second edition was 10 volumes, and by its fourth edition (1801–1810) it had expanded to 20 volumes. Its rising stature as a scholarly work helped recruit eminent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
