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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] [Amazon] |
WikiProject Aircraft
A WikiProject, or Wikiproject, is an affinity group for contributors with shared goals within the Wikimedia movement. WikiProjects are prevalent within the largest wiki, Wikipedia, and exist to varying degrees within Wikimedia project, sibling 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 Magazine, 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 outsi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Gravity
In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force between objects and the Earth. This force is dominated by the combined gravitational interactions of particles but also includes effect of the Earth's rotation. Gravity gives weight to physical objects and is essential to understanding the mechanisms responsible for surface water waves and lunar tides. Gravity also has many important biological functions, helping to guide the growth of plants through the process of gravitropism and influencing the circulation of fluids in multicellular organisms. The gravitational attraction between primordial hydrogen and clumps of dark matter in the early universe caused the hydrogen gas to coalesce, eventually condensing and fusing to form stars. At larger scales this results in galaxies and clust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Nova (American TV Series)
''Nova'' (stylized as ''NOVΛ'') is an American popular science television program produced by WGBH-TV, 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, Silicon carbide, moissanite, Project Azorian, Project Jennifer, storm chasing, German submarine U-869, Unterseeboot 869, Vinland map, Vinland, Tarim mummies, and the COVID-19 pandemic. The ''Nova'' programs have been praised for their pacing, writing, and editing. Websites that accompany the se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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, rock 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 l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 agent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 millets belong to the tribe Paniceae. Millets are important crops in the Semi-arid climate, semiarid tropics of Asia and Africa, especially in India, Mali, Nigeria, and Niger, with 97% of production in Developing country, developing countries. The crop is favoured for its Agricultural productivity, productivity and short growing season under hot dry conditions. The millets are sometimes understood to include the widely cultivated sorghum; apart from that, pearl millet is the most commonly cultivated of the millets. Finger millet, proso millet, and foxtail millet are other 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". Etymology The word ''millet'' is derived via Old French ''millet, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Ration
Rationing is the controlled distribution (marketing), distribution of scarcity, 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 high input , which would drive the market price very high. High prices, especially in the case of necessitie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cotton
Cotton (), first recorded in ancient India, 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 civilizat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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. 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 to that purpose. The bottom surface of a sleeping bag may be moderately water repellent, but a plastic Tarpaulin, tarp or groundsheet is often used to p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Wingspan
The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite 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 the distance between the length from the end of an individual's arm (measured at the fingertips) to the individual's fingertips on the other arm when raised parallel to the ground at shoulder height. Wingspan of aircraft The wingspan of an aircraft is always measured in a straight line, from wingtip to wingtip, regardless of wing shape or sweep. Implications for aircraft design and animal evolution The lift from wings is proportional to their area, so the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's pitch, and therefore the angle of attack and the lift of the wing. The elevators are usually hinged to the tailplane or horizontal stabilizer. They may be the only pitch control surface present, and are sometimes located at the front of the aircraft (early airplanes and canards) or integrated into a rear "all-moving tailplane", also called a slab elevator or stabilator. Elevator control effectiveness The elevator is a usable up and down system that controls the plane, horizontal stabilizer usually creates a ''downward'' force which balances the nose down moment created by the wing lift force, which typically applies at a point (the wing center of lift) situated aft of the airplane's center of gravity. The effects of drag and changing the engine thrust may also result in pitch moments that need to be compensated with the horizontal stabilizer. Both the horizontal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Luton Major
The Luton L.A.5 Major was a 1930s British two-seat high-wing cabin monoplane. Following World War II, plans were made available to suit construction as a homebuilt aircraft. History The original L.A.5 Major was a two-seat light aircraft powered by a 62 hp Walter Mikron II engine. It was designed by C.H. Latimer-Needham, and built in 1939 by Luton Aircraft Limited at its Phoenix Works, Gerrards Cross, Buckinghamshire. The prototype (G-AFMU), designated L.A.5 Major, first flew on 12 March 1939. During 1943, the Phoenix Works burnt down, destroying the prototype, and causing the Luton Aircraft company to close.Jackson 1974, p. 261 After World War II, Phoenix Aircraft Limited, formed by the designer C.H. Latimer-Needham and A.W.J.G. Ord-Hume, took over the design rights for the Luton Major. Latimer-Needham updated the design to make it more suitable for homebuilding, in which form it has become L.A.5A Major, with plans marketed by Falconar Avia of Edmonton, Alberta, Canada ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
