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Alan Arnold Griffith
Alan Arnold Griffith (13 June 1893 – 13 October 1963), son of Victorian science fiction writer George Griffith, was an English engineer. Among many other contributions he is best known for his work on stress and fracture in metals that is now known as metal fatigue, as well as being one of the first to develop a strong theoretical basis for the jet engine. Griffith's advanced axial-flow turbojet engine designs, were integral in the creation of Britain's first operational axial-flow turbojet engine, the Metropolitan-Vickers F.2 which first ran successfully in 1941. Griffith however had little direct involvement in actually producing the engine, after he moved in 1939 from leading the engine department at the Royal Aircraft Establishment to start work at Rolls-Royce. Early work A. A. Griffith took a first in mechanical engineering, followed by a master's degree and a Doctorate from the University of Liverpool. In 1915 he was accepted by the Royal Aircraft Factory as a traine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Aircraft Establishment
The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), before finally losing its identity in mergers with other institutions. The first site was at Farnborough Airfield ("RAE Farnborough") in Hampshire to which was added a second site RAE Bedford (Bedfordshire) in 1946. In 1988 it was renamed the Royal Aerospace Establishment (RAE) before merging with other research entities to become part of the new Defence Research Agency in 1991. History In 1904–1906 the Army Balloon Factory, which was part of the Army School of Ballooning, under the command of Colonel James Templer (balloon aviator), James Templer, relocated from Aldershot to the edge of Farnborough Common in order to have enough space to inflate the new "dirigible balloon" or airship which was then under construction.Walker, P; Early Avi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Principles In Structural Mechanics
Energy principles in structural mechanics express the relationships between Stress (physics), stresses, Strain (materials science), strains or Deformation (mechanics), deformations, displacement (vector), displacements, material properties, and structural load, external effects in the form of energy or work done by internal and external forces. Since energy is a scalar quantity, these relationships provide convenient and alternative means for formulating the governing equations of deformable bodies in solid mechanics. They can also be used for obtaining approximate solutions of fairly complex systems, bypassing the difficult task of solving the set of governing partial differential equations. General principles * Virtual work principle **Principle of virtual displacements **Principle of virtual forces ***Unit dummy force method * Modified variational principles Elastic systems * Minimum total potential energy principle * Principle of stationary total complementary potential energy * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hayne Constant
Hayne Constant, CB, CBE., MA., FRAeS., FRS, (26 September 1904 – 12 January 1968) was an English mechanical and aeronautical engineer who developed jet engines during World War II. Education Constant was born at Gravesend, the son of Frederick Charles Constant and his wife Mary Theresa (Tissie) Hayne. His father was a dental surgeon in Folkestone. Hayne was educated at King's College Choir School Cambridge, King's School, Canterbury, The Technical Institute Folkestone, Sir Roger Manwood's School, Sandwich and Queens' College, Cambridge. Career Constant stayed at Cambridge for a post graduate year in 1927/28 and then joined the Royal Aircraft Establishment at Farnborough. He became a member of the Institute of Mechanical Engineers. After six years he joined Imperial College. In 1936 Henry Tizard persuaded Constant to return to the RAE from Imperial College to help with the development of A. A. Griffith's turbine engine designs. A series of engines to Griffith's design w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Jets
Power Jets was a British company set up by Frank Whittle for the purpose of designing and manufacturing jet engines. The company was nationalised in 1944, and evolved into the National Gas Turbine Establishment. History Founded on 27 January 1936, the company consisted of Whittle, Rolf Dudley-Williams, James Collingwood Tinling, and Lancelot Law Whyte of investment bankers O T Falk & Partners. Initial premises were hired from British Thomson-Houston (BTH) at Rugby, Warwickshire. In addition to the founder members, the company initially 'borrowed' some fitters from BTH to assist in the project and later Power Jets was able to get 'one or two' people on loan from the Royal Air Force. By the beginning of 1940 the company had a total workforce of about twenty five. In 1938 Power Jets had moved from Rugby to BTH's works in Lutterworth. A major breakthrough for the company came in 1940 when at the prompting of Stanley Hooker, Ernest Hives, chairman of Rolls-Royce, visited Lutt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Ministry
The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State for Air. Organisations before the Air Ministry The Air Committee On 13 April 1912, less than two weeks after the creation of the Royal Flying Corps (which initially consisted of both a naval and a military wing), an Air Committee was established to act as an intermediary between the Admiralty and the War Office in matters relating to aviation. The new Air Committee was composed of representatives of the two war ministries, and although it could make recommendations, it lacked executive authority. The recommendations of the Air Committee had to be ratified by the Admiralty Board and the Imperial General Staff and, in consequence, the Committee was not particularly effective. The increasing separation of army and naval aviation from 191 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugal Compressor
Centrifugal compressors, sometimes called impeller compressors or radial compressors, are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. They achieve pressure rise by adding energy to the continuous flow of fluid through the rotor/impeller. The following equation shows this specific energy input. A substantial portion of this energy is kinetic which is converted to increased potential energy/static pressure by slowing the flow through a diffuser. The static pressure rise in the impeller may roughly equal the rise in the diffuser. Equation-0.1 : H = \left( \left( R \right)_2 - \left( R \right)_1 \right) :where the control volume nomenclature (illustrated in Figure-0.4) is: ::* subscript, is the impeller inlet location, station1 ::* subscript, is the impeller discharge/exit location, station2 ::* is the energy input per unit mass, units=(LP/m) ::* is the impeller's rotation speed, units=(radians/t) ::* is the radius of specified location, units=(L) ::* is ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frank Whittle
Air Commodore Sir Frank Whittle, (1 June 1907 – 8 August 1996) was an English engineer, inventor and Royal Air Force (RAF) air officer. He is credited with inventing the turbojet engine. A patent was submitted by Maxime Guillaume in 1921 for a similar invention which was technically unfeasible at the time. Whittle's jet engines were developed some years earlier than those of Germany's Hans von Ohain, who designed the first-to-fly (but never operational) turbojet engine. Whittle demonstrated an aptitude for engineering and an interest in flying from an early age. At first he was turned down by the RAF but, determined to join the force, he overcame his physical limitations and was accepted and sent to No. 2 School of Technical Training to join No 1 Squadron of Cranwell Aircraft Apprentices. He was taught the theory of aircraft engines and gained practical experience in the engineering workshops. His academic and practical abilities as an Aircraft Apprentice earned him a place ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbojet Development At The RAE
Between 1936 and 1940 Alan Arnold Griffith designed a series of turbine engines that were built under the direction of Hayne Constant at the Royal Aircraft Establishment (RAE). The designs were advanced for the era, typically featuring a "two-spool" layout with high- and low-pressure compressors that individually had more stages than typical engines of the era. Although advanced, the engines were also difficult to build, and only the much simpler "Freda" design would ever see production, as the Metrovick F.2 and later the Armstrong Siddeley Sapphire. Much of the pioneering work would be later used in Rolls-Royce designs, starting with the hugely successful Rolls-Royce Avon. Early work In 1920 W.J. Stern of the Air Ministry Laboratory in South Kensington wrote a report in response to an Aeronautical Research Committee (ARC) request about the possibilities of developing a gas turbine engine to drive a propeller. His report was extremely negative. Given the performance of existing tur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeronautical Research Committee
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] |
Turboprop
A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel is then added to the compressed air in the combustor, where the fuel-air mixture then combusts. The hot combustion gases expand through the turbine stages, generating power at the point of exhaust. Some of the power generated by the turbine is used to drive the compressor and electric generator. The gases are then exhausted from the turbine. In contrast to a turbojet or turbofan, the engine's exhaust gases do not provide enough energy to create significant thrust, since almost all of the engine's power is used to drive the propeller. Technological aspects Exhaust thrust in a turboprop is sacrificed in favor of shaft power, which is obtained by extracting additional power (beyond that necessary to drive the compressor) from turbine ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Compressor
An axial compressor is a gas compressor that can continuously pressurize gases. It is a rotating, airfoil-based compressor in which the gas or working fluid principally flows parallel to the axis of rotation, or axially. This differs from other rotating compressors such as centrifugal compressor, axi-centrifugal compressors and mixed-flow compressors where the fluid flow will include a "radial component" through the compressor. The energy level of the fluid increases as it flows through the compressor due to the action of the rotor blades which exert a torque on the fluid. The stationary blades slow the fluid, converting the circumferential component of flow into pressure. Compressors are typically driven by an electric motor or a steam or a gas turbine. Axial flow compressors produce a continuous flow of compressed gas, and have the benefits of high efficiency and large mass flow rate, particularly in relation to their size and cross-section. They do, however, require several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airfoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. A solid body moving through a fluid produces an aerodynamic force. The component of this force perpendicular to the relative freestream velocity is called lift. The component parallel to the relative freestream velocity is called drag. An airfoil is a streamlined shape that is capable of generating significantly more lift than drag. Airfoils can be designed for use at different speeds by modifying their geometry: those for subsonic flight generally have a rounded leading edge, while those designed for supersonic flight tend to be slimmer with a sharp leading edge. All have a sharp trailing edge. Foils of similar function designed with water as the working fluid are called hydrofoils. The lift on an airfoil is primarily the result o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
