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Aurora D8
The Aurora D8, also known as the D8 Airliner, is an airliner concept under development as of mid 2017. The project was initiated in 2008 by Aurora Flight Sciences, the Massachusetts Institute of Technology, Massachusetts Institute of Technology (MIT) and Pratt & Whitney under NASA's sponsorship of $2.9 million (£2.19 million). Aurora is refining the fuel-efficient D8 designed for NASA by MIT, hoping to fly a half-scale demonstrator in 2022. The 180-seat, -range airliner is designed to fly at within the capabilities of the Boeing 737 or Airbus A320 and could be in test service by 2027 at the earliest and 2035 at the latest. Aurora Flight Sciences was purchased by Boeing on November 8, 2017 for their drone developments. The subsidiary is intended to accelerate Boeing's development of autonomous technology. Design The side-by-side "double bubble" fuselage provides additional lift along the nose section as well as faster Aircraft ground handling, turnaround owing to its wider fuse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wide-body Aircraft
A wide-body aircraft, also known as a twin-aisle aircraft, is an airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast. The typical fuselage diameter is . In the typical wide-body economy cabin, passengers are seated seven to ten abreast, allowing a total capacity of 200 to 850 passengers. The largest wide-body aircraft are over wide, and can accommodate up to eleven passengers abreast in high-density configurations. By comparison, a typical narrow-body airliner has a diameter of , with a single aisle, and seats between two and six people abreast. Wide-body aircraft were originally designed for a combination of efficiency and passenger comfort and to increase the amount of cargo space. However, airlines quickly gave in to economic factors, and reduced the extra passenger space in order to insert more seats and increase revenue and profits. Wide-body aircraft are also used for the transport of commercial freight and cargo and ... [...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 engine, 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 Propelling nozzle, jet thrust relative to fan thrust are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tip Clearance
Tip clearance is the distance between the tip of a rotating airfoil and a stationary part. * Gas turbine: Rotor blade and casing * Propeller (ship or aircraft): Propeller and structure ** Ground tip clearanc* Wind turbine A wind turbine is a device that converts the kinetic energy of wind into electrical energy. Hundreds of thousands of large turbines, in installations known as wind farms, now generate over 650 gigawatts of power, with 60 GW added each year. ...: blade and tower References {{reflist Mechanical engineering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Technologies
United Technologies Corporation (UTC) was an American multinational conglomerate headquartered in Farmington, Connecticut. It researched, developed, and manufactured products in numerous areas, including aircraft engines, aerospace systems, HVAC, elevators and escalators, fire and security, building automation, and industrial products, among others. UTC was also a large military contractor, getting about 10% of its revenue from the U.S. government. Gregory J. Hayes was the CEO and chairman. In April 2020 UTC merged with the Raytheon Company to form Raytheon Technologies. History Pre-1970s 1970s and 1980s In 1974, Harry Gray left Litton Industries to become the CEO of United Aircraft.. He pursued a strategy of growth and diversification, changing the parent corporation's name to United Technologies Corporation (UTC) in 1975 to reflect the intent to diversify into numerous high tech fields beyond aerospace.. (The change became official on May 1, 1975.) The diversificati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Flow
Mass flow, also known as mass transfer and bulk flow, is the movement of fluids down a pressure or temperature gradient,Moyes & Schulte (2008). Principles of Animal Physiology. Pearson Benjamin Cummings. San Francisco, California particularly in the life sciences. As such, mass flow is a subject of study in both fluid dynamics and biology. Examples of mass flow include blood circulation and transport of water in vascular plant tissues. Mass flow is not to be confused with diffusion which depends on concentration gradients within a medium rather than pressure gradients of the medium itself. Plant biology In general, bulk flow in plant biology typically refers to the movement of water from the soil up through the plant to the leaf tissue through xylem, but can also be applied to the transport of larger solutes (e.g. sucrose) through the phloem. Xylem According to cohesion-tension theory, water transport in xylem relies upon the cohesion of water molecules to each other and adhesio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Nozzle
A propelling nozzle is a nozzle that converts the internal energy of a working gas into propulsive force; it is the nozzle, which forms a jet, that separates a gas turbine, or gas generator, from a jet engine. Propelling nozzles accelerate the available gas to subsonic, transonic, or supersonic velocities depending on the power setting of the engine, their internal shape and the pressures at entry to, and exit from, the nozzle. The internal shape may be convergent or convergent-divergent (C-D). C-D nozzles can accelerate the jet to supersonic velocities within the divergent section, whereas a convergent nozzle cannot accelerate the jet beyond sonic speed. Propelling nozzles may have a fixed geometry, or they may have variable geometry to give different exit areas to control the operation of the engine when equipped with an afterburner or a reheat system. When afterburning engines are equipped with a C-D nozzle the throat area is variable. Nozzles for supersonic flight speeds, at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind-tunnel
Wind tunnels are large tubes with air blowing through them which are used to replicate the interaction between air and an object flying through the air or moving along the ground. Researchers use wind tunnels to learn more about how an aircraft will fly. NASA uses wind tunnels to test scale models of aircraft and spacecraft. Some wind tunnels are large enough to contain full-size versions of vehicles. The wind tunnel moves air around an object, making it seem as if the object is flying. Most of the time, large powerful fans suck air through the tube. The object being tested is held securely inside the tunnel so that it remains stationary. The object can be an aerodynamic test object such as a cylinder or an airfoil, an individual component, a small model of the vehicle, or a full-sized vehicle. The air moving around the stationary object shows what would happen if the object was moving through the air. The motion of the air can be studied in different ways; smoke or dye can be p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Thrust
Specific thrust is the thrust per unit air mass flowrate of a jet engine (e.g. turbojet, turbofan, etc.) and can be calculated by the ratio of net thrust/total intake airflow. Low specific thrust engines tend to be more efficient of propellant (at subsonic speeds), but also have a lower effective exhaust velocity and lower maximum airspeed. Engines considered to have high specific thrust are mostly used for supersonic speeds, and extremely high specific thrust engines can achieve hypersonic speeds. Low specific thrust engines A modern civil turbofan has a low specific thrust (~30 lbf/(lb/s)) to keep the jet noise at an acceptable level, and to achieve low fuel consumption, because a low specific thrust helps to improve specific fuel consumption (SFC).{{Cite web, url=https://www.grc.nasa.gov/www/k-12/airplane/sfc.html, title=Specific Fuel Consumption, website=www.grc.nasa.gov, access-date=2016-04-25 This low specific thrust is usually achieved with a high bypass ratio. Addit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propulsive Efficiency
In aerospace engineering, concerning aircraft, rocket and spacecraft design, overall propulsion system efficiency \eta is the efficiency with which the energy contained in a vehicle's fuel is converted into kinetic energy of the vehicle, to accelerate it, or to replace losses due to aerodynamic drag or gravity. Mathematically, it is represented as \eta = \eta_c \eta_p, where \eta_c is the cycle efficiency and \eta_p is the propulsive efficiency. The cycle efficiency is expressed as the percentage of the heat energy in the fuel that is converted to mechanical energy in the engine, and the propulsive efficiency is expressed as the proportion of the mechanical energy actually used to propel the aircraft. The propulsive efficiency is always less than one, because conservation of momentum requires that the exhaust have some of the kinetic energy, and the propulsive mechanism (whether propeller, jet exhaust, or ducted fan) is never perfectly efficient. It is greatly dependent on exhaust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exhaust Velocity
Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine (a rocket using propellant or a jet engine using fuel) creates thrust. For engines whose reaction mass is only the fuel they carry, specific impulse is exactly proportional to the effective exhaust gas velocity. A propulsion system with a higher specific impulse uses the mass of the propellant more efficiently. In the case of a rocket, this means less propellant needed for a given delta-v, so that the vehicle attached to the engine can more efficiently gain altitude and velocity. In an atmospheric context, specific impulse can include the contribution to impulse provided by the mass of external air that is accelerated by the engine in some way, such as by an internal turbofan or heating by fuel combustion participation then thrust expansion or by external propeller. Jet engines breathe external air for both combustion and by-pass, and therefore have a much higher specific impulse than r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeing 737NG
The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a narrow-body aircraft powered by two jet engines and produced by Boeing Commercial Airplanes. Launched in 1993 as the third generation derivative of the Boeing 737, it has been produced since 1997 and is an upgrade of the 737 Classic (−300/-400/-500) series. It has a redesigned wing with a larger area, a wider wingspan, greater fuel capacity, and higher maximum takeoff weights (MTOW) and longer range. It has CFM International CFM56-7 series engines, a glass cockpit, and upgraded and redesigned interior configurations. The series includes four variants, the −600/-700/-800/-900, seating between 108 and 215 passengers. The 737NG's primary competition is the Airbus A320 family. , a total of 7,124 737NG aircraft had been ordered, of which 7,096 had been delivered, with remaining orders for two -800, and 26 -800A variants. The most produced variant was the 737-800, with 4,991 commercial, 191 mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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