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Colditz Cock
The Colditz Cock was a glider built by British prisoners of war during World War II for an escape attempt from Oflag IV-C (Colditz Castle) prison camp in Germany. Background After the execution of 50 prisoners who had taken part in the " Great Escape" from Stalag Luft III, the Allied High Command had discouraged escape attempts, though the plan to build a glider was encouraged in order to divert the energies of the prisoners from descending into boredom and tedium. The idea for the glider came from Lieutenant Tony Rolt. Rolt, who was not even an airman, had noticed the chapel roof line was completely obscured from the German guards' view. He realised that the roof would make a perfect launching point from which the glider could fly across the River Mulde, which was about 60 metres below. Construction The team was headed by Bill Goldfinch and Jack Best. Goldfinch and Best were aided by their discovery in the prison library of ''Aircraft Design'', a two-volume work by C.H. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WikiProject Aircraft
A WikiProject, or Wikiproject, is a Wikimedia movement affinity group for contributors with shared goals. WikiProjects are prevalent within the largest wiki, Wikipedia, and exist to varying degrees within sister projects such as Wiktionary, Wikiquote, Wikidata, and Wikisource. They also exist in different languages, and translation of articles is a form of their collaboration. During the COVID-19 pandemic, CBS News noted the role of Wikipedia's WikiProject Medicine in maintaining the accuracy of articles related to the disease. Another WikiProject that has drawn attention is WikiProject Women Scientists, which was profiled by '' Smithsonian'' for its efforts to improve coverage of women scientists which the profile noted had "helped increase the number of female scientists on Wikipedia from around 1,600 to over 5,000". On Wikipedia Some Wikipedia WikiProjects are substantial enough to engage in cooperative activities with outside organizations relevant to the field at issue. For e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles (or thereabouts depending on wing sweep) to the fuselage. The spar carries flight loads and the weight of the wings while on the ground. Other structural and forming members such as ribs may be attached to the spar or spars, with stressed skin construction also sharing the loads where it is used. There may be more than one spar in a wing or none at all. Where a single spar carries most of the force, it is known as the main spar. Spars are also used in other aircraft aerofoil surfaces such as the tailplane and fin and serve a similar function, although the loads transmitted may be different from those of a wing spar. Spar loads The wing spar provides the majority of the weight support and dynamic load integrity of cantilever monoplanes, often coupled with the strength of the wing 'D' box itself. Together, these two structural components collectively provide the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonograph
A phonograph, in its later forms also called a gramophone (as a trademark since 1887, as a generic name in the UK since 1910) or since the 1940s called a record player, or more recently a turntable, is a device for the mechanical and analogue recording and reproduction of sound. The sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, etched, incised, or impressed into the surface of a rotating cylinder or disc, called a "record". To recreate the sound, the surface is similarly rotated while a playback stylus traces the groove and is therefore vibrated by it, very faintly reproducing the recorded sound. In early acoustic phonographs, the stylus vibrated a diaphragm which produced sound waves which were coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones. The phonograph was invented in 1877 by Thomas Edison. Alexander Graham Bell's Volta Laboratory made s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beech
Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engleriana'' subgenus is found only in East Asia, distinctive for its low branches, often made up of several major trunks with yellowish bark. The better known ''Fagus'' subgenus beeches are high-branching with tall, stout trunks and smooth silver-grey bark. The European beech (''Fagus sylvatica'') is the most commonly cultivated. Beeches are monoecious, bearing both male and female flowers on the same plant. The small flowers are unisexual, the female flowers borne in pairs, the male flowers wind-pollinating catkins. They are produced in spring shortly after the new leaves appear. The fruit of the beech tree, known as beechnuts or mast, is found in small burrs that drop from the tree in autumn. They are small, roughly triangular, and edible, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nova (American TV Series)
''Nova'' (stylized as ''NOVΛ'') is an American popular science television program produced by WGBH in Boston, Massachusetts, since 1974. It is broadcast on PBS in the United States, and in more than 100 other countries. The program has won many major television awards. ''Nova'' often includes interviews with scientists doing research in the subject areas covered and occasionally includes footage of a particular discovery. Some episodes have focused on the history of science. Examples of topics covered include the following: Colditz Castle, the Drake equation, elementary particles, the 1980 eruption of Mount St. Helens, Fermat's Last Theorem, the AIDS epidemic, global warming, moissanite, Project Jennifer, storm chasing, Unterseeboot 869, Vinland, Tarim mummies, and the COVID-19 pandemic. The ''Nova'' programs have been praised for their pacing, writing, and editing. Websites that accompany the segments have also won awards. Episodes History ''Nova'' was first aired o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porosity
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam). There are many ways to test porosity in a substance or part, such as industrial CT scanning. The term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, petrophysics, hydrology, earth sciences, soil mechanics, and engineering. Void fraction in two-phase flow In gas-liquid two-phase flow, the void fraction is defined as the fraction of the flow-channel volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. Void fraction usually varies from location to location in the flow ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Dope
Aircraft dope is a plasticised lacquer that is applied to fabric-covered aircraft. It tightens and stiffens fabric stretched over airframes, which renders them airtight and weatherproof, increasing their durability and lifespan.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 170. Aviation Supplies & Academics, 1997. The technique has been commonly applied to both full-size and flying models of aircraft. Attributes Doping techniques have been employed in aircraft construction since the dawn of heavier-than-air flight; the fabric of the ground-breaking Wright Flyer had benefitted from doping, as did many of the aircraft that soon followed. Without the application of dope, fabric coverings lacked durability while being highly flammable, both factors rendering them far less viable. By the 1910s, a wide variety of doping agents had entered widespread use while entirely original formulas were being regularly introduced in the industry. Typical doping agents in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millet
Millets () are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. Most species generally referred to as millets belong to the tribe Paniceae, but some millets also belong to various other taxa. Millets are important crops in the semiarid tropics of Asia and Africa (especially in India, Mali, Nigeria, and Niger), with 97% of millet production in developing countries. This crop is favored due to its productivity and short growing season under dry, high-temperature conditions. Millets are indigenous to many parts of the world. The most widely grown millets are sorghum and pearl millets, which are important crops in India and parts of Africa. Finger millet, proso millet, and foxtail millet are also important crop species. Millets may have been consumed by humans for about 7,000 years and potentially had "a pivotal role in the rise of multi-crop agriculture and settled farming societies." Descript ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ration
Rationing is the controlled distribution of scarce resources, goods, services, or an artificial restriction of demand. Rationing controls the size of the ration, which is one's allowed portion of the resources being distributed on a particular day or at a particular time. There are many forms of rationing, although rationing by price is most prevalent. Rationing is often done to keep price below the market clearing, market-clearing price determined by the process of supply and demand in an free market, unfettered market. Thus, rationing can be complementary to incomes policies, price controls. An example of rationing in the face of rising prices took place in the various countries where there was rationing of gasoline during the 1973 energy crisis. A reason for setting the price lower than would clear the market may be that there is a shortage, which would drive the market price very high. High prices, especially in the case of necessities, are undesirable with regard to those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor percentages of waxes, fats, pectins, and water. Under natural conditions, the cotton bolls will increase the dispersal of the seeds. The plant is a shrub native to tropical and subtropical regions around the world, including the Americas, Africa, Egypt and India. The greatest diversity of wild cotton species is found in Mexico, followed by Australia and Africa. Cotton was independently domesticated in the Old and New Worlds. The fiber is most often spun into yarn or thread and used to make a soft, breathable, and durable textile. The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric dated to the fifth millennium BC have been found in the Indus Valley civilization, as well as fabric remnants dated back ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleeping Bag
A sleeping bag is an insulated covering for a person, essentially a lightweight quilt that can be closed with a zipper or similar means to form a tube, which functions as lightweight, portable bedding in situations where a person is sleeping outdoors (e.g. when camping, hiking, hill walking or climbing). It is also commonly used indoors for people who do not have beds or at sleepovers for when one or more persons cannot all fit in the bed or do not feel comfortable sleeping with someone. Its primary purpose is to provide warmth and thermal insulation through its synthetic or down insulation. It also typically has a water-resistant or water-repellent cover that protects, to some extent, against wind chill and light precipitation, but a tent is usually used in addition to a sleeping bag, as it performs those functions better. The bottom surface also provides some cushioning, but a sleeping pad or camp cot is usually used in addition for that purpose. The bottom surface of a sleep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wingspan
The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the other wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan of , the official record for a living bird. The term wingspan, more technically extent, is also used for other winged animals such as pterosaurs, bats, insects, etc., and other aircraft such as ornithopters. In humans, the term wingspan also refers to the arm span, which is distance between the length from one end of an individual's arms (measured at the fingertips) to the other when raised parallel to the ground at shoulder height at a 90º angle. Former professional basketball player Manute Bol stood at and owned one of the largest wingspans at . Wingspan of aircraft The wingspan of an aircraft is always measured in a straight line, from wingtip to wingtip, independently of wing shape or sweep. Implications for aircraft design and anima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
