A jet engine is a type of reaction engine discharging a fast-moving jet that generates thrust by jet propulsion. This broad definition includes airbreathing jet engines. In general, jet engines are combustion engines.
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 accelerate air rearwards. Thus, whereas all the air taken in by a turbojet passes through the turbine, in a turbofan some of that air bypasses the turbine. 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.
An aircraft engine is a component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines, except for small multicopter UAVs which are almost always electric aircraft.
A jet aircraft is an aircraft propelled by jet engines.
The turbojet is an airbreathing jet engine, typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet, a compressor, a combustion chamber, and a turbine. The compressed air from the compressor is heated by the 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.
An afterburner is a component present on some jet engines, mostly those used on military supersonic aircraft. Its purpose is to provide an increase in thrust, usually for supersonic flight, takeoff, and combat situations. Afterburning is achieved by injecting additional fuel into the jet pipe downstream of the turbine. Afterburning significantly increases thrust without the weight of an additional engine, but at the cost of very high fuel consumption and decreased fuel efficiency, limiting its practical use to short bursts.
The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core.
The General Electric TF39 is a high-bypass turbofan engine developed to power the Lockheed C-5 Galaxy. The TF39 was the first high-power, high-bypass jet engine ever developed. The TF39 was further developed into the CF6 series of engines, and formed the basis of the General Electric LM2500 marine and industrial gas turbine. On September 7, 2017 the very last active C-5A powered with TF39 engines made its final flight to Davis-Monthan Air Force Base for retirement. The TF39 was effectively retired, and all remaining active C-5 Galaxys are now powered by General Electric F138-GE-100 (CF6) engines.
The General Electric J79 is an axial-flow turbojet engine built for use in a variety of fighter and bomber aircraft and a supersonic cruise missile. The J79 was produced by General Electric Aircraft Engines in the United States, and under license by several other companies worldwide.
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, being gas generator, from a jet engine.
The Metropolitan-Vickers F.2 was an early turbojet engine and the first British design to be based on an axial-flow compressor. It was an extremely advanced design for the era, using a nine-stage axial compressor, annular combustor, and a two-stage turbine.
The Rolls-Royce/SNECMA M45H was a medium bypass ratio turbofan produced specifically for the twin-engined VFW-Fokker 614 aircraft in the early 1970s.
The General Electric YF120 was a variable cycle turbofan engine designed by GE Aircraft Engines in the late 1980s/early 1990s for the United States Air Force's Advanced Tactical Fighter (ATF) project. GE lost the engine competition for this aircraft to Pratt & Whitney F119.
The air turborocket is a form of combined-cycle jet engine. The basic layout includes a gas generator, which produces high pressure gas, that drives a turbine/compressor assembly which compresses atmospheric air into a combustion chamber. This mixture is then combusted before leaving the device through a nozzle and creating thrust.
The Rolls-Royce/Snecma Olympus 593 was an Anglo-French afterburning (reheated) turbojet which powered the supersonic airliner Concorde. It was initially a joint project between Bristol Siddeley Engines Limited (BSEL) and Snecma. It was based on the Bristol Siddeley Olympus 22R engine. Rolls-Royce Limited acquired BSEL in 1966 during development of the engine making BSEL the Bristol Engine Division of Rolls-Royce.
The General Electric CF700 is an aft-fan turbofan development of the CJ610 turbojet. The fan blades are an extension of the low-pressure turbine blades.
An airbreathing jet engine is a jet engine propelled by a jet of hot exhaust gases formed from air that is forced into the engine by several stages of centrifugal, axial or ram compression, which is then heated and expanded through a nozzle. They are typically gas turbine engines. The majority of the mass flow through an airbreathing jet engine is provided by air taken from outside of the engine and heated internally, using energy stored in the form of fuel.
A powered aircraft is an aircraft that uses onboard propulsion with mechanical power generated by an aircraft engine of some kind.
