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C. N. H. Lock
Christopher Noel Hunter Lock (21 December 1894 – 27 March 1949) was a British aerodynamicist, after whom the Lock number is named. Biography Lock was born at Herschel House, Cambridge, the youngest son of John Bascombe Lock (18 March 1849 – 8 September 1921) who was bursar of Gonville and Caius College, Cambridge, and Emily née Baily. His brother was Robert Heath Lock. Lock was a Scholar at Charterhouse School, and in 1912 was awarded a Major Scholarship at Gonville and Caius College, where he was the only b* wrangler of 1917. He took his BA in 1917, won a Smith's Prize in 1919, and became a fellow of Caius College in 1920. He was a member of the Anti-Aircraft Experimental Section, and in 1920 moved to the Aerodynamics Division of the National Physical Laboratory in Teddington, to work on the dynamics of shells. He conducted wide-ranging experiments, including on autogyros, and became an authority on airscrews. From 1939 until his death, he ran the Aerodynamics Division ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock Number
In helicopter aerodynamics, the Lock number is the ratio of aerodynamic forces, which act to lift the rotor blades, to inertial forces, which act to maintain the blades in the plane of rotation. It is named after C. N. H. Lock, a British aerodynamicist who studied autogyros in the 1920s. Typical rotorcraft blades have a Lock number between 3 and 12, usually approximately 8. The Lock number is typically 8 to 10 for articulated rotors and 5 to 7 for hingeless rotors. High-stiffness blades may have a Lock number up to 14. Larger blades have a higher mass and more inertia, so tend to have a lower Lock number. Helicopter rotors with more than two blades can have lighter blades, so tend to have a higher Lock number. A low Lock number gives good autorotation characteristics due to higher inertia, however this comes with a mass penalty. Ray Prouty writes, "The previously discussed numbers: Mach, Reynolds and Froude are used in many fields of fluid dynamic studies. The Lock number is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Profile Drag
Parasitic drag, also known as profile drag, is a type of aerodynamic drag that acts on any object when the object is moving through a fluid. Parasitic drag is a combination of form drag and skin friction drag. It affects all objects regardless of whether they are capable of generating lift. Total drag on an aircraft is made up of parasitic drag and lift-induced drag. Parasitic drag comprises all types of drag except lift-induced drag. Form drag Form drag arises because of the shape of the object. The general size and shape of the body are the most important factors in form drag; bodies with a larger presented cross-section will have a higher drag than thinner bodies; sleek ("streamlined") objects have lower form drag. Form drag follows the drag equation, meaning that it increases with the square of the velocity, and thus becomes more important for high-speed aircraft. Form drag depends on the longitudinal section of the body. A prudent choice of body profile is essential for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1894 Births
Events January–March * January 4 – A military alliance is established between the French Third Republic and the Russian Empire. * January 7 – William Kennedy Dickson receives a patent for motion picture film in the United States. * January 9 – New England Telephone and Telegraph installs the first battery-operated telephone switchboard, in Lexington, Massachusetts. * February 12 ** French anarchist Émile Henry sets off a bomb in a Paris café, killing one person and wounding twenty. ** The barque ''Elisabeth Rickmers'' of Bremerhaven is wrecked at Haurvig, Denmark, but all crew and passengers are saved. * February 15 ** In Korea, peasant unrest erupts in the Donghak Peasant Revolution, a massive revolt of followers of the Donghak movement. Both China and Japan send military forces, claiming to come to the ruling Joseon dynasty government's aid. ** At 04:51 GMT, French anarchist Martial Bourdin dies of an accidental detonation of his own ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fellows Of Gonville And Caius College, Cambridge
Fellows may refer to Fellow, in plural form. Fellows or Fellowes may also refer to: Places *Fellows, California, USA *Fellows, Wisconsin, ghost town, USA Other uses *Fellows Auctioneers, established in 1876. * Fellowes, Inc., manufacturer of workspace products *Fellows, a partner in the firm of English canal carriers, Fellows Morton & Clayton *Fellows (surname) See also *North Fellows Historic District The North Fellows Historic District is a historic district located in Ottumwa, Iowa, United States. The city experienced a housing boom after World War II. This north side neighborhood of single-family brick homes built between 1945 and 1959 ..., listed on the National Register of Historic Places in Wapello County, Iowa * Justice Fellows (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballistics Experts
Ballistics is the field of mechanics concerned with the launching, flight behaviour and impact effects of projectiles, especially ranged weapon munitions such as bullets, unguided bombs, rockets or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance. A ballistic body is a free-moving body with momentum which can be subject to forces such as the forces exerted by pressurized gases from a gun barrel or a propelling nozzle, normal force by rifling, and gravity and air drag during flight. A ballistic missile is a missile that is missile guidance, guided only during the relatively brief initial phase of powered flight and the trajectory is subsequently governed by the laws of classical mechanics; in contrast to (for example) a cruise missile which is aerodynamics, aerodynamically guided in powered flight like a fixed-wing aircraft. History and prehistory The earliest known ballistic projectiles were stones and spears, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
St Leonard's Church, Streatham
St Leonard's Church is a Church of England parish church in the London Borough of Lambeth. It is a Grade II listed building and occupies a prominent position on the west side of Streatham High Road, at its junction with Tooting Bec Gardens and Mitcham Lane. Parish Streatham is an ancient parish which is mentioned in the Domesday Book and originally included land in the districts that are now generally known as Balham and Tooting Bec. In response to the great increase in the local population during the 19th and 20th centuries, parts of the area of the original parish of St Leonard's were assigned to form the whole or parts of these more newly created parishes: * All Saints, West Dulwich * Ascension, Balham Hill * Christ Church, Streatham * Holy Trinity, Tulse Hill * Holy Trinity, Upper Tooting * Immanuel, Streatham * St Margaret the Queen, Streatham Hill * St Peter, Streatham * St Alban, Streatham Park * St Andrew, Lower Streatham * St Anselm, Coventry Park * St James, West ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advisory Committee For Aeronautics
The Advisory Committee for Aeronautics (ACA) was a UK agency founded on 30 April 1909, to undertake, promote, and institutionalize aeronautical research. In 1919 it was renamed the Aeronautical Research Committee, later becoming the Aeronautical Research Council. Following the establishment of this committee, other countries created similar agencies, notably the French ''L’Etablissement Central de l’Aérostation Militaire'' in Meudon (now ''ONERA''), the Russian "Aerodynamic Institute of Koutchino" and the U.S.A.'s National Advisory Committee for Aeronautics, founded in 1915. The Aeronautical Research Council was disbanded in 1979. Origins The idea for the creation of the ACA originated with the then Secretary of State for War, R.B.Haldane (later First Viscount Haldane), who was supported in his efforts by the Prime Minister of the United Kingdom H. H. Asquith. Asquith announced the committee's appointment in a statement to the House of Commons on 5 May 1909, in which h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mach Number
Mach number (M or Ma) (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is named after the Moravian physicist and philosopher Ernst Mach. : \mathrm = \frac, where: : is the local Mach number, : is the local flow velocity with respect to the boundaries (either internal, such as an object immersed in the flow, or external, like a channel), and : is the speed of sound in the medium, which in air varies with the square root of the thermodynamic temperature. By definition, at Mach1, the local flow velocity is equal to the speed of sound. At Mach0.65, is 65% of the speed of sound (subsonic), and, at Mach1.35, is 35% faster than the speed of sound (supersonic). Pilots of high-altitude aerospace vehicles use flight Mach number to express a vehicle's true airspeed, but the flow field around a vehicle varies in three dimensions, with corresponding variations in local Mach number. The loc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swept Wing
A swept wing is a wing that angles either backward or occasionally Forward-swept wing, forward from its root rather than in a straight sideways direction. Swept wings have been flown since the pioneer days of aviation. Wing sweep at high speeds was first investigated in Germany as early as 1935 by Albert Betz and Adolph Busemann, finding application just before the end of the Second World War. It has the effect of delaying the shock waves and accompanying aerodynamic drag rise caused by fluid compressibility near the speed of sound, improving performance. Swept wings are therefore almost always used on jet aircraft designed to fly at these speeds. The term "swept wing" is normally used to mean "swept back", but variants include forward-swept wing, forward sweep, Variable-sweep wing, variable sweep wings and oblique wings in which one side sweeps forward and the other back. The delta wing is also aerodynamically a form of swept wing. Reasons for sweep There are three main reasons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitot Tube
A pitot ( ) tube (pitot probe) measures fluid flow velocity. It was invented by a French engineer, Henri Pitot, in the early 18th century, and was modified to its modern form in the mid-19th century by a French scientist, Henry Darcy. It is widely used to determine the airspeed of aircraft; the water speed of boats; and the flow velocity of liquids, air, and gases in industry. Theory of operation The basic pitot tube consists of a tube pointing directly into the fluid flow. As this tube contains fluid, a pressure can be measured; the moving fluid is brought to rest (stagnates) as there is no outlet to allow flow to continue. This pressure is the stagnation pressure of the fluid, also known as the total pressure or (particularly in aviation) the pitot pressure. The measured stagnation pressure cannot itself be used to determine the fluid flow velocity (airspeed in aviation). However, Bernoulli's equation states: :Stagnation pressure = static pressure + dynamic pressure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Bascombe Lock
John Bascombe Lock (18 March 1849–8 Sep 1921) was an English priest and academic, who was bursar of Gonville and Caius College, Cambridge and author of several mathematical textbooks. He was born 18 March 1849 in Dorchester, son of Joseph Lock (27 Sep 1811–17 Jan 1877), a butcher and farmer, and Elizabeth Marvin née Wills. He was baptised on 24 June 1849 at St Peter's Church, Dorchester. He was educated at William Barnes's School, Dorchester; Bristol Grammar School; and Gonville and Caius College, Cambridge, where he gained his BA in 1872. He was ordained deacon in 1872, and priest in 1873. He was assistant master at Eton College from 1872 to 1884, living there in the 1881 census. From 1874 he was a fellow at Caius, and bursar from 1889 until his death. He was instrumental in the creation of many university buildings. He was also the Chairman of Addenbrooke's Hospital. In 1901 he founded the Gog Magog Golf Club. On 23 Dec 1873 he married Emily née Baily (1 Oct 1851–14 Sep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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