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Silent Aircraft Initiative
The Silent Aircraft Initiative was a study undertaken by the Cambridge-MIT Institute to discover ways to reduce aircraft noise dramatically, to the point where it would be virtually unnoticeable to people outside the airport perimeter. Launched in November 2003, the program has the support of Rolls-Royce, Boeing and Marshall Aerospace. Part of the study is examining if a steeper continuous descent into an airport will reduce approach noise levels. Theoretical analysis will be backed up by field trials using real jetliners. A major part of the study is developing jetliner and engine designs that can meet the SAI objectives. The favoured configuration is a blended wing design, with the engines located on the upper surface of the wing, to shield ground observers from the engine noise. A very low specific thrust (i.e. very high bypass ratio) turbofan is proposed for the aircraft. Engine handling and low jet noise are facilitated by the use of a variable area final nozzle, to rematch th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Noise
Aircraft noise pollution refers to noise produced by aircraft in flight that has been associated with several negative stress-mediated health effects, from sleep disorders to cardiovascular ones. Governments have enacted extensive controls that apply to aircraft designers, manufacturers, and operators, resulting in improved procedures and cuts in pollution. Sound production is divided into three categories: * Mechanical noise—rotation of the engine parts, most noticeable when fan blades reach supersonic speeds. * Aerodynamic noise—from the airflow around the surfaces of the aircraft, especially when flying low at high speeds. * Noise from aircraft systems—cockpit and cabin pressurization and conditioning systems, and Auxiliary Power units. Mechanisms of sound production Aircraft noise is noise pollution produced by an aircraft or its components, whether on the ground while parked such as auxiliary power units, while taxiing, on run-up from propeller and jet exhaust, duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airport
An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface such as a runway for a plane to take off and to land or a helipad, and often includes adjacent utility buildings such as control towers, hangars and terminals, to maintain and monitor aircraft. Larger airports may have airport aprons, taxiway bridges, air traffic control centres, passenger facilities such as restaurants and lounges, and emergency services. In some countries, the US in particular, airports also typically have one or more fixed-base operators, serving general aviation. Operating airports is extremely complicated, with a complex system of aircraft support services, passenger services, and aircraft control services contained within the operation. Thus airports can be major employers, as well as important hubs for tou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolls-Royce Plc
Rolls-Royce Holdings plc is a British multinational aerospace and defence company incorporated in February 2011. The company owns Rolls-Royce, a business established in 1904 which today designs, manufactures and distributes power systems for aviation and other industries. Rolls-Royce is the world's second-largest maker of aircraft engines (after General Electric) and has major businesses in the marine propulsion and energy sectors. Rolls-Royce was the world's 16th largest defence contractor in 2018 when measured by defence revenues. Rolls-Royce Holdings plc is listed on the London Stock Exchange, where it is a constituent of the FTSE 100 Index. At the close of London trading on 28 August 2019, the company had a market capitalisation of £4.656bn, the 85th-largest of any company with a primary listing on the London Stock Exchange. The company's registered office is at Kings Place, near Kings Cross in London. History Ownership Rolls-Royce grew from the engineering busin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeing
The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product support services. Boeing is among the largest global aerospace manufacturers; it is the third-largest defense contractor in the world based on 2020 revenue, and is the largest exporter in the United States by dollar value. Boeing stock is included in the Dow Jones Industrial Average. Boeing is incorporated in Delaware. Boeing was founded by William Boeing in Seattle, Washington, on July 15, 1916. The present corporation is the result of the merger of Boeing with McDonnell Douglas on August 1, 1997. Then chairman and CEO of Boeing, Philip M. Condit, assumed those roles in the combined company, while Harry Stonecipher, former CEO of McDonnell Douglas, became president and COO. The Boeing Company's corporate headquarters is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marshall Aerospace
Marshall Group, formerly Marshall of Cambridge and Marshall Aerospace and Defence Group, is a British company headquartered in Cambridge, United Kingdom. Subsidiaries include Marshall Aerospace, an aircraft maintenance, modification, and design company located at Cambridge City Airport. Other subsidiaries are Marshall Land Systems (ground defence) and Marshall Slingsby Advanced Composites. Marshall also owns and operates the airport itself. The company was originally founded by David Gregory Marshall in 1909. Initially operating chauffeur services, the firm soon branched out into vehicle repair and dealership activities. During the 1930s, Marshall became increasingly engaged in aviation; by the end of the Second World War, the company had trained in excess of 20,000 aircrew for service within the Royal Air Force. It was also engaged in repair and modification of military aircraft during the conflict. During the postwar era, the Marshall companies have been involved in aerosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blended Wing
A blended wing body (BWB), also known as blended body or hybrid wing body (HWB), is a fixed-wing aircraft having no clear dividing line between the wings and the main body of the craft. The aircraft has distinct wing and body structures, which are smoothly blended together with no clear dividing line.Crane, Dale. ''Dictionary of Aeronautical Terms, third edition''. Newcastle, Washington: Aviation Supplies & Academics, 1997. . p. 224. This contrasts with a flying wing, which has no distinct fuselage, and a lifting body, which has no distinct wings. A BWB design may or may not be tailless. The main advantage of the BWB is to reduce wetted area and the accompanying form drag associated with a conventional wing-body junction. It may also be given a wide airfoil-shaped body, allowing the entire craft to generate lift and thus reducing the size and drag of the wings. The BWB configuration is used for both aircraft and underwater gliders. History In the early 1920s Nicolas Woyevodsk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbofan
The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which achieves mechanical energy from combustion, and the ''fan'', a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust. The ratio of the mass-flow of air bypassing the engine core to the mass-flow of air passing through the core is referred to as the bypass ratio. The engine produces thrust through a combination of these two portions working together; engines that use more jet thrust relative to fan thrust are known as ''low-bypass turbofans'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nozzle
A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe. A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or modify the flow of a fluid (liquid or gas). Nozzles are frequently used to control the rate of flow, speed, direction, mass, shape, and/or the pressure of the stream that emerges from them. In a nozzle, the velocity of fluid increases at the expense of its pressure energy. Types Jet A gas jet, fluid jet, or hydro jet is a nozzle intended to eject gas or fluid in a coherent stream into a surrounding medium. Gas jets are commonly found in gas stoves, ovens, or barbecues. Gas jets were commonly used for light before the development of electric light. Other types of fluid jets are found in carburetors, where smooth calibrated orifices are used to regulate the flow of fuel into an engine, and in jacuzzis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fan (mechanical)
A fan is a powered machine used to create a flow of air. A fan consists of a rotating arrangement of vanes or blades, generally made of wood, plastic, or metal, which act on the air. The rotating assembly of blades and hub is known as an ''impeller'', ''rotor'', or ''runner''. Usually, it is contained within some form of housing, or case. This may direct the airflow, or increase safety by preventing objects from contacting the fan blades. Most fans are powered by electric motors, but other sources of power may be used, including hydraulic motors, handcranks, and internal combustion engines. Mechanically, a fan can be any revolving vane, or vanes used for producing currents of air. Fans produce air flows with high volume and low pressure (although higher than ambient pressure), as opposed to compressors which produce high pressures at a comparatively low volume. A fan blade will often rotate when exposed to an air-fluid stream, and devices that take advantage of this, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intake
An intake (also inlet) is an opening, structure or system through which a fluid is admitted to a space or machine as a consequence of a pressure differential between the outside and the inside. The pressure difference may be generated on the inside by a mechanism, or on the outside by ram pressure or hydrostatic pressure. Flow rate through the intake depends on pressure difference, fluid properties, and intake geometry. Intake refers to an opening, or area, together with its defining edge profile which has an associated entry loss, that captures pipe flow from a reservoir or storage tank. Intake refers to the capture area definition and attached ducting to an aircraft gas turbine engine or ramjet engine and, as such, an intake is followed by a compressor or combustion chamber. It may instead be referred to as a diffuser. For an automobile engine the components through which the air flows to the engine cylinders, are collectively known as an intake system and may include the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbomachinery
Turbomachinery, in mechanical engineering, describes machines that transfer energy between a rotor (turbine), rotor and a fluid, including both turbines and gas compressor, compressors. While a turbine transfers energy from a fluid to a rotor, a compressor transfers energy from a rotor to a fluid.Logan, Earl. "Handbook of turbomachinery". 1995. Marcel Deckker.Vandad Talimi (Original author unknown). "Mechanical Equipment and Systems". 2013. Memorial University of Newfoundland. http://www.engr.mun.ca/~yuri/Courses/MechanicalSystems/Turbomachinery.pdf These two types of machines are governed by the same basic relationships including Newton's Laws of Motion, Newton's second Law of Motion and Euler's pump and turbine equation for compressible fluids. Centrifugal pumps are also turbomachines that transfer energy from a rotor to a fluid, usually a liquid, while turbines and compressors usually work with a gas. History The first turbomachines could be identified as water wheels, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
