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Jet-engine
A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, water jet, and hybrid propulsion, the term typically refers to an internal combustion airbreathing jet engine such as a turbojet, turbofan, ramjet, or pulse jet. In general, jet engines are internal combustion engines. Airbreathing jet engines typically feature a rotating air compressor powered by a turbine, with the leftover power providing thrust through the propelling nozzle—this process is known as the Brayton thermodynamic cycle. Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines that were relatively inefficient for subsonic flight. Most modern subsonic jet aircraft use more complex high-bypass turbofan engines. They give higher speed and greater fuel efficiency than piston and propeller aeroengines over long distances. A few air-bre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Von Ohain
Hans Joachim Pabst von Ohain (14 December 191113 March 1998) was a German physicist, engineer, and the designer of the first operational jet engine. Together with Frank Whittle he is called the "father of the jet engine". His first test unit ran on hydrogen in March 1937, and it was a later development that powered the world's first flyable all-jet aircraft, the experimental Heinkel He 178 (He 178 V1) in late August 1939. In spite of these early successes, which started the world´s first jet producing industry in Germany, other German designs quickly eclipsed Ohain's, and none of his engine designs entered widespread production or operational use. Von Ohain started to develop his first turbojet engine designs independently during the same period that Whittle was working on his own similar designs in Britain, and their turbojet designs are said by some to be an example of simultaneous invention. The core of Ohain's first jet engine, the Heinkel HeS 1, which he described as his "hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbojet
The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and a turbine (that drives the compressor). The compressed air from the compressor is heated by burning fuel in the combustion chamber and then allowed to expand through the turbine. The turbine exhaust is then expanded in the propelling nozzle where it is accelerated to high speed to provide thrust. Two engineers, Frank Whittle in the United Kingdom and Hans von Ohain in Germany, developed the concept independently into practical engines during the late 1930s. Turbojets have poor efficiency at low vehicle speeds, which limits their usefulness in vehicles other than aircraft. Turbojet engines have been used in isolated cases to power vehicles other than aircraft, typically for attempts on land speed records. Where vehicles are "turbine-powere ... [...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] |
Airstrikes In Syria 140923-F-UL677-654
An airstrike, air strike or air raid is an offensive operation carried out by aircraft. Air strikes are delivered from aircraft such as blimps, balloons, fighters, heavy bombers, ground attack aircraft, attack helicopters and drones. The official definition includes all sorts of targets, including enemy air targets, but in popular usage the term is usually narrowed to a tactical (small-scale) attack on a ground or naval objective as opposed to a larger, more general attack such as carpet bombing. Weapons used in an airstrike can range from direct-fire aircraft-mounted cannons and machine guns, rockets and air-to-surface missiles, to various types of aerial bombs, glide bombs, cruise missiles, ballistic missiles, and even directed-energy weapons such as laser weapons. In close air support, air strikes are usually controlled by trained observers on the ground for coordination with ground troops and intelligence in a manner derived from artillery tactics. History Beginnings On ... [...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] |
Internal Combustion Engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons ( piston engine), turbine blades (gas turbine), a rotor (Wankel engine), or a nozzle ( jet engine). This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. This replaced the external combustion engine for applications where the weight or size of an engine was more important. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1860, and the first modern internal combustion engine, known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Jet Engine
300px, Diagram of a pulsejet A pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need to have air forced into its inlet, typically by forward motion). The best known example may be the Argus As 109-014 used to propel Nazi Germany's V-1 flying bomb. Pulsejet engines are a lightweight form of jet propulsion, but usually have a poor compression ratio, and hence give a low specific impulse. There are two main types of pulsejet engines, both of which use resonant combustion and harness the expanding combustion products to form a pulsating exhaust jet that produces thrust intermittently. The first is known as a valved or traditional pulsejet and it has a set of one-way valves through which the incoming air passes. When the air-fuel is ignited, these valves slam shut, which means that the hot gases can only leave through the engin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ramjet
A ramjet, or athodyd (aero thermodynamic duct), is a form of airbreathing jet engine that uses the forward motion of the engine to produce thrust. Since it produces no thrust when stationary (no ram air) ramjet-powered vehicles require an assisted take-off like a rocket assist to accelerate it to a speed where it begins to produce thrust. Ramjets work most efficiently at supersonic speeds around and can operate up to speeds of . Ramjets can be particularly useful in applications requiring a small and simple mechanism for high-speed use, such as missiles. The US, Canada, and UK had widespread ramjet powered missile defenses during the 1960s onward, such as the CIM-10 Bomarc and Bloodhound. Weapon designers are looking to use ramjet technology in artillery shells to give added range; a 120 mm mortar shell, if assisted by a ramjet, is thought to be able to attain a range of . They have also been used successfully, though not efficiently, as tip jets on the ends of helicopt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airbreathing Jet Engine
An airbreathing jet engine (or ''ducted jet engine'') is a jet engine that ejects a propelling (reaction) jet of hot exhaust gases after first taking in atmospheric air, followed by compression, heating and expansion back to atmospheric pressure through a nozzle. Alternatively the reaction jet may include a cold jet of ducted bypass air which has been compressed by a fan before returning to atmospheric pressure through an additional nozzle. These engines are gas turbine engines. Engines using only ram for the compression process, and no turbomachinery, are the ramjet and pulsejet. All practical airbreathing jet engines heat the air by burning fuel. Alternatively a heat exchanger may be used ( nuclear-powered jet engine). Most modern jet engines are turbofans. They replaced turbojets as they use less fuel. Background The original air-breathing gas turbine jet engine was the turbojet. It was a concept brought to life by two engineers, Frank Whittle in England UK and Hans von Oha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pump-jet
A pump-jet, hydrojet, or water jet is a marine system that produces a jet of water for propulsion. The mechanical arrangement may be a ducted propeller (axial-flow pump), a centrifugal pump, or a mixed flow pump which is a combination of both centrifugal and axial designs. The design also incorporates an intake to provide water to the pump and a nozzle to direct the flow of water out of the pump.http://www.hamiltonmarine.co.nz/includes/files_cms/file/JetTorque%2008.pdf Design A pump-jet works by having an intake (usually at the bottom of the hull) that allows water to pass underneath the vessel into the engines. Water enters the pump through this inlet. The pump can be of a centrifugal design for high speeds, or an axial flow pump for low to medium speeds. The water pressure inside the inlet is increased by the pump and forced backwards through a nozzle. With the use of a ''reversing bucket'', reverse thrust can also be achieved for faring backwards, quickly and withou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket Engine
A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accordance with Newton's third law. Most rocket engines use the combustion of reactive chemicals to supply the necessary energy, but non-combusting forms such as cold gas thrusters and nuclear thermal rockets also exist. Vehicles propelled by rocket engines are commonly called rockets. Rocket vehicles carry their own oxidiser, unlike most combustion engines, so rocket engines can be used in a vacuum to propel spacecraft and ballistic missiles. Compared to other types of jet engine, rocket engines are the lightest and have the highest thrust, but are the least propellant-efficient (they have the lowest specific impulse). The ideal exhaust is hydrogen, the lightest of all elements, but chemical rockets produce a mix of heavier species, reducing the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Propulsion
Jet propulsion is the propulsion of an object in one direction, produced by ejecting a jet of fluid in the opposite direction. By Newton's third law, the moving body is propelled in the opposite direction to the jet. Reaction engines operating on the principle of jet propulsion include the jet engine used for aircraft propulsion, the pump-jet used for marine propulsion, and the rocket engine and plasma thruster used for spacecraft propulsion. Physics Jet propulsion is produced by some reaction engines or animals when thrust is generated by a fast moving jet of fluid in accordance with Newton's laws of motion. It is most effective when the Reynolds number is high—that is, the object being propelled is relatively large and passing through a low-viscosity medium. In animals, the most efficient jets are pulsed, rather than continuous, at least when the Reynolds number is greater than 6. Specific impulse Specific impulse (usually abbreviated ''I''sp) is a measure of how effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
