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77-509: Two prototype aircraft were ordered on 11 February 1944 that were designated XP-81. The engine selection was an attempt to couple the high-speed capability of the jet engine with the endurance offered by the propeller engine. The XP-81 was designed to use the General Electric TG-100 turboprop engine (later designated XT31 by the US military) in the nose driving a four-bladed propeller and

154-460: A GE J33 turbojet in the rear fuselage. The turboprop would be used for normal flight and cruising and the turbojet added for high-speed flight. The first XP-81 (serial 44-91000) was completed in January 1945 but because of developmental problems the turboprop engine was not ready for installation. A decision was then made to mount a complete V-1650-7 engine package from a P-51D aircraft in place of

231-399: A convergent-divergent nozzle is needed on high-speed aircraft. The engine thrust is highest if the static pressure of the gas reaches the ambient value as it leaves the nozzle. This only happens if the nozzle exit area is the correct value for the nozzle pressure ratio (npr). Since the npr changes with engine thrust setting and flight speed this is seldom the case. Also at supersonic speeds

308-403: A helicopter . The fuel economy of an automobile relates to the distance traveled by a vehicle and the amount of fuel consumed . Consumption can be expressed in terms of the volume of fuel to travel a distance, or the distance traveled per unit volume of fuel consumed. Since fuel consumption of vehicles is a significant factor in air pollution, and since the importation of motor fuel can be

385-675: 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-breathing engines made for high-speed applications (ramjets and scramjets ) use

462-569: A car and the production, transmission and storage of electricity and hydrogen, the label "zero pollution" applies only to the car's conversion of stored energy into movement. In 2004, a consortium of major auto-makers — BMW , General Motors , Honda , Toyota and Volkswagen / Audi — came up with "Top Tier Detergent Gasoline Standard" to gasoline brands in the US and Canada that meet their minimum standards for detergent content and do not contain metallic additives. Top Tier gasoline contains higher levels of detergent additives in order to prevent

539-399: A central gas turbine which drives open-air contra-rotating propellers . Unlike turboprop engines, in which the propeller and the engine are considered two separate products, the propfan’s gas generator and its unshrouded propeller module are heavily integrated and are considered to be a single product. Additionally, the propfan’s short, heavily twisted variable pitch blades closely remember

616-399: A change in buying habits with a propensity to heavier vehicles that are less fuel-efficient. Energy efficiency is similar to fuel efficiency but the input is usually in units of energy such as megajoules (MJ), kilowatt-hours (kW·h), kilocalories (kcal) or British thermal units (BTU). The inverse of "energy efficiency" is " energy intensity ", or the amount of input energy required for

693-408: A compressor ( axial , centrifugal , or both), mixing fuel with the compressed air, burning the mixture in the combustor , and then passing the hot, high pressure air through a turbine and a nozzle . The compressor is powered by the turbine, which extracts energy from the expanding gas passing through it. The engine converts internal energy in the fuel to increased momentum of the gas flowing through

770-486: A diesel engine. See Brake-specific fuel consumption for more information. The energy efficiency in transport is the useful travelled distance , of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels , electrical energy or food energy . The energy efficiency

847-469: A heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units: The specific energy content of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram). It is sometimes called the heat of combustion . There exists two different values of specific heat energy for

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924-462: A higher priority than fuel efficiency, fans tend to be smaller or absent. Because of these distinctions, turbofan engine designs are often categorized as low-bypass or high-bypass , depending upon the amount of air which bypasses the core of the engine. Low-bypass turbofans have a bypass ratio of around 2:1 or less. A propfan engine is a type of airbreathing jet engine which combines aspects of turboprop and turbofan . It’s design consists of

1001-406: A jet of water. The mechanical arrangement may be a ducted propeller with nozzle, or a centrifugal compressor and nozzle. The pump-jet must be driven by a separate engine such as a Diesel or gas turbine . All jet engines are reaction engines that generate thrust by emitting a jet of fluid rearwards at relatively high speed. The forces on the inside of the engine needed to create this jet give

1078-426: A large number of different types of jet engines, all of which achieve forward thrust from the principle of jet propulsion . Commonly aircraft are propelled by airbreathing jet engines. Most airbreathing jet engines that are in use are turbofan jet engines, which give good efficiency at speeds just below the speed of sound. A turbojet engine is a gas turbine engine that works by compressing air with an inlet and

1155-467: A large part of a nation's foreign trade , many countries impose requirements for fuel economy. Different methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses ( wind resistance , tire drag , and others) encountered while propelling the vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of

1232-495: A number of countries still using other systems, fuel economy is expressed in miles per gallon (mpg), for example in the US and usually also in the UK ( imperial gallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable. Traditionally, litres per mil were used in Norway and Sweden , but both have aligned to

1309-728: A powerplant for the world's first jet- fighter aircraft , the Messerschmitt Me 262 (and later the world's first jet- bomber aircraft, the Arado Ar 234 ). A variety of reasons conspired to delay the engine's availability, causing the fighter to arrive too late to improve Germany's position in World War II , however this was the first jet engine to be used in service. Meanwhile, in Britain the Gloster E28/39 had its maiden flight on 15 May 1941 and

1386-403: A series of hydrogen fueling stations has been established. Powered either through chemical reactions in a fuel cell that create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a natural gas vehicle , and similarly compatible with both natural gas and gasoline); these vehicles promise to have near-zero pollution from

1463-459: A small combustion engine is combined with electric motors. Kinetic energy which would otherwise be lost to heat during braking is recaptured as electrical power to improve fuel efficiency. The larger batteries in these vehicles power the car's electronics , allowing the engine to shut off and avoid prolonged idling . Fleet efficiency describes the average efficiency of a population of vehicles. Technological advances in efficiency may be offset by

1540-530: A strong thrust on the engine which pushes the craft forwards. Jet engines make their jet from propellant stored in tanks that are attached to the engine (as in a 'rocket') as well as in duct engines (those commonly used on aircraft) by ingesting an external fluid (very typically air) and expelling it at higher speed. A propelling nozzle produces a high velocity exhaust jet . Propelling nozzles turn internal and pressure energy into high velocity kinetic energy. The total pressure and temperature don't change through

1617-421: A supersonic afterburning engine or 2200 K with afterburner lit. The pressure entering the nozzle may vary from 1.5 times the pressure outside the nozzle, for a single stage fan, to 30 times for the fastest manned aircraft at Mach 3+. Convergent nozzles are only able to accelerate the gas up to local sonic (Mach 1) conditions. To reach high flight speeds, even greater exhaust velocities are required, and so

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1694-461: A two-stage axial compressor feeding a single-sided centrifugal compressor . Practical axial compressors were made possible by ideas from A.A.Griffith in a seminal paper in 1926 ("An Aerodynamic Theory of Turbine Design"). Whittle would later concentrate on the simpler centrifugal compressor only. Whittle was unable to interest the government in his invention, and development continued at a slow pace. In Spain, pilot and engineer Virgilio Leret Ruiz

1771-472: A unit of output such as MJ/passenger-km (of passenger transport), BTU/ton-mile or kJ/t-km (of freight transport), GJ/t (for production of steel and other materials), BTU/(kW·h) (for electricity generation), or litres/100 km (of vehicle travel). Litres per 100 km is also a measure of "energy intensity" where the input is measured by the amount of fuel and the output is measured by the distance travelled. For example: Fuel economy in automobiles . Given

1848-572: Is a form of thermal efficiency , meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier ( fuel ) into kinetic energy or work . Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile . Non-transportation applications, such as industry , benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion , such as ammonia production during

1925-517: Is a popular topic in the field of artificial intelligence (AI) and machine learning (ML). The main factors representing and influencing driving behavior include velocity, acceleration, gear, road parameters, weather, etc. Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency. Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques

2002-444: Is a twin-spool engine, allowing only two different speeds for the turbines. Ram compression jet engines are airbreathing engines similar to gas turbine engines in so far as they both use the Brayton cycle . Gas turbine and ram compression engines differ, however, in how they compress the incoming airflow. Whereas gas turbine engines use axial or centrifugal compressors to compress incoming air, ram engines rely only on air compressed in

2079-493: 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 may include rocket , water jet , and hybrid propulsion, the term jet engine typically refers to an internal combustion air-breathing jet engine such as a turbojet , turbofan , ramjet , pulse jet , or scramjet . In general, jet engines are internal combustion engines . Air-breathing jet engines typically feature

2156-401: Is also occasionally known as energy intensity . The inverse of the energy efficiency in transport is the energy consumption in transport. Energy efficiency in transport is often described in terms of fuel consumption , fuel consumption being the reciprocal of fuel economy. Nonetheless, fuel consumption is linked with a means of propulsion which uses liquid fuels , whilst energy efficiency

2233-530: Is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the International System of Units , i.e., joules . Therefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m/J, while the energy consumption in transport

2310-485: Is called " hypermiling ". The most efficient machines for converting energy to rotary motion are electric motors, as used in electric vehicles . However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account. Railway trains can be powered using electricity, delivered through an additional running rail, overhead catenary system or by on-board generators used in diesel-electric locomotives as common on

2387-400: Is dependent on many parameters of a vehicle, including its engine parameters, aerodynamic drag , weight, AC usage, fuel and rolling resistance . There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits. Hybrid vehicles use two or more power sources for propulsion. In many designs,

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2464-500: Is documented in the story of Ottoman soldier Lagâri Hasan Çelebi , who reportedly achieved flight using a cone-shaped rocket in 1633. The earliest attempts at airbreathing jet engines were hybrid designs in which an external power source first compressed air, which was then mixed with fuel and burned for jet thrust. The Italian Caproni Campini N.1 , and the Japanese Tsu-11 engine intended to power Ohka kamikaze planes towards

2541-443: Is measured in terms of joules per metre, or J/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The energy efficiency in transport largely varies by means of transport. Different types of transport range from some hundred kilojoules per kilometre (kJ/km) for a bicycle to tens of megajoules per kilometre (MJ/km) for

2618-533: Is not formed and complete combustion occurs., National Aeronautics and Space Administration, April 2005. Experiments by NASA in microgravity reveal that diffusion flames in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions. LSP-1 experiment results , National Aeronautics and Space Administration, April 2005. Premixed flames in microgravity burn at

2695-400: Is the propellant flow in kg/s, A e {\displaystyle A_{e}} is the cross-sectional area at the exit of the exhaust nozzle, and p {\displaystyle p} is the atmospheric pressure. Combined-cycle engines simultaneously use two or more different principles of jet propulsion. A water jet, or pump-jet, is a marine propulsion system that uses

2772-566: Is used for launching satellites, space exploration and crewed access, and permitted landing on the Moon in 1969. Rocket engines are used for high altitude flights, or anywhere where very high accelerations are needed since rocket engines themselves have a very high thrust-to-weight ratio . However, the high exhaust speed and the heavier, oxidizer-rich propellant results in far more propellant use than turbofans. Even so, at extremely high speeds they become energy-efficient. An approximate equation for

2849-434: Is very low. This was reflected in a study by AEA Technology between a Eurostar train and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO 2 , per passenger, than planes, helped in part by French nuclear generation. In the future, hydrogen cars may be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where

2926-867: The Gloster Meteor finally entered service with the RAF in July 1944. These were powered by turbojet engines from Power Jets Ltd., set up by Frank Whittle. The first two operational turbojet aircraft, the Messerschmitt Me 262 and then the Gloster Meteor entered service within three months of each other in 1944; the Me 262 in April and the Gloster Meteor in July. The Meteor only saw around 15 aircraft enter World War II action, while up to 1400 Me 262 were produced, with 300 entering combat, delivering

3003-527: The Haber process . In the context of transport , fuel economy is the energy efficiency of a particular vehicle, given as a ratio of distance traveled per unit of fuel consumed. It is dependent on several factors including engine efficiency , transmission design, and tire design. In most countries, using the metric system , fuel economy is stated as "fuel consumption" in liters per 100 kilometers (L/100 km) or kilometers per liter (km/L or kmpl). In

3080-500: The aeolipile , a device described by Hero of Alexandria in 1st-century Egypt . This device directed steam power through two nozzles to cause a sphere to spin rapidly on its axis. It was seen as a curiosity. Meanwhile, practical applications of the turbine can be seen in the water wheel and the windmill . Historians have further traced the theoretical origin of the principles of jet engines to traditional Chinese firework and rocket propulsion systems. Such devices' use for flight

3157-655: The gasoline -fuelled HeS 3 of 5 kN (1,100 lbf), which was fitted to Heinkel's simple and compact He 178 airframe and flown by Erich Warsitz in the early morning of August 27, 1939, from Rostock -Marienehe aerodrome , an impressively short time for development. The He 178 was the world's first jet plane. Heinkel applied for a US patent covering the Aircraft Power Plant by Hans Joachim Pabst von Ohain on May 31, 1939; patent number US2256198, with M Hahn referenced as inventor. Von Ohain's design, an axial-flow engine, as opposed to Whittle's centrifugal flow engine,

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3234-399: The latent heat of vaporization of water. The difference between the high and low values is significant, about 8 or 9%. This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U.S. (and the table) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used. Neither the gross heat of combustion nor

3311-402: The ram effect of the vehicle's speed instead of a mechanical compressor. The thrust of a typical jetliner engine went from 5,000 lbf (22 kN) ( de Havilland Ghost turbojet) in the 1950s to 115,000 lbf (510 kN) ( General Electric GE90 turbofan) in the 1990s, and their reliability went from 40 in-flight shutdowns per 100,000 engine flight hours to less than 1 per 100,000 in

3388-532: The 1950s, the jet engine was almost universal in combat aircraft, with the exception of cargo, liaison and other specialty types. By this point, some of the British designs were already cleared for civilian use, and had appeared on early models like the de Havilland Comet and Avro Canada Jetliner . By the 1960s, all large civilian aircraft were also jet powered, leaving the piston engine in low-cost niche roles such as cargo flights. The efficiency of turbojet engines

3465-512: The British embassy in Madrid a few years later by his wife, Carlota O'Neill , upon her release from prison. In 1935, Hans von Ohain started work on a similar design to Whittle's in Germany, both compressor and turbine being radial, on opposite sides of the same disc, initially unaware of Whittle's work. Von Ohain's first device was strictly experimental and could run only under external power, but he

3542-454: The EU standard of L/100 km. Fuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements. Weight-specific efficiency (efficiency per unit weight) may be stated for freight , and passenger-specific efficiency (vehicle efficiency per passenger) for passenger vehicles. Fuel efficiency

3619-526: The Pratt & Whitney J57 and J75 models. There is also a derivative of the P&;W JT8D low-bypass turbofan that creates up to 35,000 horsepower (HP) . Jet engines are also sometimes developed into, or share certain components such as engine cores, with turboshaft and turboprop engines, which are forms of gas turbine engines that are typically used to power helicopters and some propeller-driven aircraft. There are

3696-519: The US and UK rail networks. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than "on site". Pollution can be reduced by using more railway electrification and low carbon power for electricity. Some railways, such as the French SNCF and Swiss federal railways derive most, if not 100% of their power, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks

3773-631: The XP-81 was returned to Vultee Field, the TG-100 turboprop was installed and flight testing resumed, including the first flight by an American turboprop-powered aircraft on 21 December 1945. However, the turboprop engine was not able to produce its designed power; producing only the same output as the Merlin (1,490 hp or 1112 kW) with the resultant performance limited to that of the Merlin-engined version. With

3850-422: The build-up of deposits (typically, on fuel injector and intake valve ) known to reduce fuel economy and engine performance. How fuel combusts affects how much energy is produced. The National Aeronautics and Space Administration (NASA) has investigated fuel consumption in microgravity . The common distribution of a flame under normal gravity conditions depends on convection , because soot tends to rise to

3927-469: The capture of Guam and Saipan obviated the need for long-range, high-speed escort fighters and then, just before VJ Day the contract was cancelled, after 85% of the engineering was completed. The YP-81 was to be essentially the same as the prototype but with a lighter and more powerful GE TG-110 (XT41) turboprop engine, the wing moved aft 10 inches (0.25 m), and armament of either six .50 cal (12.7 mm) machine guns or six 20 mm cannon. After

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4004-495: The conversions between the chemical energy in the fuel and the kinetic energy of the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy braking waste energy. Energy-efficient driving techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly. The relationship between fuel consumption and driving behavior

4081-626: The divergent area is less than required to give complete internal expansion to ambient pressure as a trade-off with external body drag. Whitford gives the F-16 as an example. Other underexpanded examples were the XB-70 and SR-71. The nozzle size, together with the area of the turbine nozzles, determines the operating pressure of the compressor. This overview highlights where energy losses occur in complete jet aircraft powerplants or engine installations. Fuel efficiency Fuel efficiency (or fuel economy )

4158-510: The ducted fan blades of turbofan engines. Propfans are designed to offer the speed and performance of turbofan engines with fuel efficiency of turboprops. However, due to low fuel costs and high cabin noise, early propfan projects were abandoned. Very few aircraft have flown with propfans, with the Antonov An-70 being the first and only aircraft to fly while being powered solely by propfan engines. The term Advanced technology engine refers to

4235-405: The end of World War II were unsuccessful. Even before the start of World War II, engineers were beginning to realize that engines driving propellers were approaching limits due to issues related to propeller efficiency, which declined as blade tips approached the speed of sound . If aircraft performance were to increase beyond such a barrier, a different propulsion mechanism was necessary. This

4312-650: The engine, producing thrust. All the air entering the compressor is passed through the combustor, and turbine, unlike the turbofan engine described below. Turbofans differ from turbojets in that they have an additional fan at the front of the engine, which accelerates air in a duct bypassing the core gas turbine engine. Turbofans are the dominant engine type for medium and long-range airliners . Turbofans are usually more efficient than turbojets at subsonic speeds, but at high speeds their large frontal area generates more drag . Therefore, in supersonic flight, and in military and other aircraft where other considerations have

4389-463: The first ground attacks and air combat victories of jet planes. Following the end of the war the German jet aircraft and jet engines were extensively studied by the victorious allies and contributed to work on early Soviet and US jet fighters. The legacy of the axial-flow engine is seen in the fact that practically all jet engines on fixed-wing aircraft have had some inspiration from this design. By

4466-712: The form of rocket engines they power model rocketry , spaceflight , and military missiles . Jet engines have propelled high speed cars, particularly drag racers , with the all-time record held by a rocket car . A turbofan powered car, ThrustSSC , currently holds the land speed record . Jet engine designs are frequently modified for non-aircraft applications, as industrial gas turbines or marine powerplants . These are used in electrical power generation, for powering water, natural gas, or oil pumps, and providing propulsion for ships and locomotives. Industrial gas turbines can create up to 50,000 shaft horsepower. Many of these engines are derived from older military turbojets such as

4543-490: The inlet or diffuser. A ram engine thus requires a substantial initial forward airspeed before it can function. Ramjets are considered the simplest type of air breathing jet engine because they have no moving parts in the engine proper, only in the accessories. Scramjets differ mainly in the fact that the air does not slow to subsonic speeds. Rather, they use supersonic combustion. They are efficient at even higher speed. Very few have been built or flown. The rocket engine uses

4620-458: The late 1990s. This, combined with greatly decreased fuel consumption, permitted routine transatlantic flight by twin-engined airliners by the turn of the century, where previously a similar journey would have required multiple fuel stops. The principle of the jet engine is not new; however, the technical advances necessary to make the idea work did not come to fruition until the 20th century. A rudimentary demonstration of jet power dates back to

4697-433: The modern generation of jet engines. The principle is that a turbine engine will function more efficiently if the various sets of turbines can revolve at their individual optimum speeds, instead of at the same speed. The true advanced technology engine has a triple spool, meaning that instead of having a single drive shaft, there are three, in order that the three sets of blades may revolve at different speeds. An interim state

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4774-484: The net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in Gibbs free energy , and is around 45.7 MJ/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the specific fuel consumption ) depends on the engine. A figure of 17.6 MJ/kg is possible with a gasoline engine, and 19.1 MJ/kg for

4851-394: The net thrust of a rocket engine is: Where F N {\displaystyle F_{N}} is the net thrust, I sp,vac {\displaystyle I_{\text{sp,vac}}} is the specific impulse , g 0 {\displaystyle g_{0}} is a standard gravity , m ˙ {\displaystyle {\dot {m}}}

4928-404: The nozzle but their static values drop as the gas speeds up. The velocity of the air entering the nozzle is low, about Mach 0.4, a prerequisite for minimizing pressure losses in the duct leading to the nozzle. The temperature entering the nozzle may be as low as sea level ambient for a fan nozzle in the cold air at cruise altitudes. It may be as high as the 1000 Kelvin exhaust gas temperature for

5005-424: The same basic physical principles of thrust as a form of reaction engine , but is distinct from the jet engine in that it does not require atmospheric air to provide oxygen; the rocket carries all components of the reaction mass. However some definitions treat it as a form of jet propulsion . Because rockets do not breathe air, this allows them to operate at arbitrary altitudes and in space. This type of engine

5082-426: The same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the exhaust is in liquid form. For the low value, the exhaust has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the liquid water value is larger since it includes

5159-531: The state of the art in compressors. Alan Arnold Griffith published An Aerodynamic Theory of Turbine Design in 1926 leading to experimental work at the RAE . In 1928, RAF College Cranwell cadet Frank Whittle formally submitted his ideas for a turbojet to his superiors. In October 1929, he developed his ideas further. On 16 January 1930, in England, Whittle submitted his first patent (granted in 1932). The patent showed

5236-408: The tailpipe (exhaust pipe). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by electrolysis using electricity from non-polluting sources such as solar, wind or hydroelectricity or nuclear. Commercial hydrogen production uses fossil fuels and produces more carbon dioxide than hydrogen. Because there are pollutants involved in the manufacture and destruction of

5313-603: The termination of hostilities, the two prototypes continued to be tested until 1947 when they were both consigned to a bombing range as photography targets. Note: Performance is estimated with "full powered" TG-100. Armament is projected only. Data from Jane's all the World's Aircraft 1947; General Dynamics Aircraft and Their Predecessors General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Jet engine A jet engine

5390-435: The top of a flame, such as in a candle, making the flame yellow. In microgravity or zero gravity , such as an environment in outer space , convection no longer occurs, and the flame becomes spherical , with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is the hypothesis that the temperature is evenly distributed enough that soot

5467-577: The turboprop for initial flight tests. This was done in a week and the Merlin-powered XP-81 was sent to the Muroc airbase where it flew for the first time on 11 February 1945. During 10 flight test hours, the XP-81 displayed good handling characteristics except for inadequate directional stability due to the longer forward portion of the fuselage (this was rectified by enlarging the vertical tail ). While 13 YP-81 pre-production aircraft had been ordered,

5544-600: Was able to demonstrate the basic concept. Ohain was then introduced to Ernst Heinkel , one of the larger aircraft industrialists of the day, who immediately saw the promise of the design. Heinkel had recently purchased the Hirth engine company, and Ohain and his master machinist Max Hahn were set up there as a new division of the Hirth company. They had their first HeS 1 centrifugal engine running by September 1937. Unlike Whittle's design, Ohain used hydrogen as fuel, supplied under external pressure. Their subsequent designs culminated in

5621-406: Was built in 1903 by Norwegian engineer Ægidius Elling . Such engines did not reach manufacture due to issues of safety, reliability, weight and, especially, sustained operation. The first patent for using a gas turbine to power an aircraft was filed in 1921 by Maxime Guillaume . His engine was an axial-flow turbojet, but was never constructed, as it would have required considerable advances over

5698-571: Was eventually adopted by most manufacturers by the 1950s. Austrian Anselm Franz of Junkers ' engine division ( Junkers Motoren or "Jumo") introduced the axial-flow compressor in their jet engine. Jumo was assigned the next engine number in the RLM 109-0xx numbering sequence for gas turbine aircraft powerplants, "004", and the result was the Jumo 004 engine. After many lesser technical difficulties were solved, mass production of this engine started in 1944 as

5775-574: Was granted a patent for a jet engine design in March 1935. Republican president Manuel Azaña arranged for initial construction at the Hispano-Suiza aircraft factory in Madrid in 1936, but Leret was executed months later by Francoist Moroccan troops after unsuccessfully defending his seaplane base on the first days of the Spanish Civil War . His plans, hidden from Francoists, were secretly given to

5852-427: Was still rather worse than piston engines, but by the 1970s, with the advent of high-bypass turbofan jet engines (an innovation not foreseen by the early commentators such as Edgar Buckingham , at high speeds and high altitudes that seemed absurd to them), fuel efficiency was about the same as the best piston and propeller engines. Jet engines power jet aircraft , cruise missiles and unmanned aerial vehicles . In

5929-409: Was the motivation behind the development of the gas turbine engine, the most common form of jet engine. The key to a practical jet engine was the gas turbine , extracting power from the engine itself to drive the compressor . The gas turbine was not a new idea: the patent for a stationary turbine was granted to John Barber in England in 1791. The first gas turbine to successfully run self-sustaining

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