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62-524: The de Havilland Goblin , originally designated as the Halford H-1 , is an early turbojet engine designed by Frank Halford and built by de Havilland . The Goblin was the second British jet engine to fly, after Whittle's Power Jets W.1 , and the first to pass a type test and receive a type certificate issued for an aircraft propulsion turbine. Although it was conceived in 1941 it remained unchanged in basic form for 13 years by which time it had evolved to

124-416: A i r + m ˙ f ) V j − m ˙ a i r V {\displaystyle F_{N}=({\dot {m}}_{air}+{\dot {m}}_{f})V_{j}-{\dot {m}}_{air}V} where: If the speed of the jet is equal to sonic velocity the nozzle is said to be " choked ". If the nozzle is choked, the pressure at the nozzle exit plane

186-580: A gas turbine to power an aircraft was filed in 1921 by Frenchman Maxime Guillaume . His engine was to be an axial-flow turbojet, but was never constructed, as it would have required considerable advances over the state of the art in compressors. In 1928, British 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

248-542: A landing field, lengthening flights. The increase in reliability that came with the turbojet enabled three- and two-engine designs, and more direct long-distance flights. High-temperature alloys were a reverse salient , a key technology that dragged progress on jet engines. Non-UK jet engines built in the 1930s and 1940s had to be overhauled every 10 or 20 hours due to creep failure and other types of damage to blades. British engines, however, utilised Nimonic alloys which allowed extended use without overhaul, engines such as

310-454: A second generation SST engine using the 593 core were done more than three years before Concorde entered service. They evaluated bypass engines with bypass ratios between 0.1 and 1.0 to give improved take-off and cruising performance. Nevertheless, the 593 met all the requirements of the Concorde programme. Estimates made in 1964 for the Concorde design at Mach 2.2 showed the penalty in range for

372-411: A significant impact on commercial aviation . Aside from giving faster flight speeds turbojets had greater reliability than piston engines, with some models demonstrating dispatch reliability rating in excess of 99.9%. Pre-jet commercial aircraft were designed with as many as four engines in part because of concerns over in-flight failures. Overseas flight paths were plotted to keep planes within an hour of

434-405: A small helicopter engine compressor rotates around 50,000 RPM. Turbojets supply bleed air from the compressor to the aircraft for the operation of various sub-systems. Examples include the environmental control system , anti-icing , and fuel tank pressurization. The engine itself needs air at various pressures and flow rates to keep it running. This air comes from the compressor, and without it,

496-558: A speed of 403.10 miles per hour (648.73 km/h) on Lake Eyre , Australia. This became the official FIA LSR, although Campbell was disappointed not to have beaten Breedlove's time. In October, several four-wheel jet-cars surpassed the 1963 mark, but were eligible for neither FIA nor FIM ratification. The confusion of having three different LSRs lasted until December 11, 1964, when the FIA and FIM met in Paris and agreed to recognize as an absolute LSR

558-513: A turbojet application, where the output from the gas turbine is used in a propelling nozzle, raising the turbine temperature increases the jet velocity. At normal subsonic speeds this reduces the propulsive efficiency, giving an overall loss, as reflected by the higher fuel consumption, or SFC. However, for supersonic aircraft this can be beneficial, and is part of the reason why the Concorde employed turbojets. Turbojet systems are complex systems therefore to secure optimal function of such system, there

620-512: A turbojet engine is always subsonic, regardless of the speed of the aircraft itself. The intake has to supply air to the engine with an acceptably small variation in pressure (known as distortion) and having lost as little energy as possible on the way (known as pressure recovery). The ram pressure rise in the intake is the inlet's contribution to the propulsion system's overall pressure ratio and thermal efficiency . The intake gains prominence at high speeds when it generates more compression than

682-494: A turbojet is high enough at higher thrust settings to cause the nozzle to choke. If, however, a convergent-divergent de Laval nozzle is fitted, the divergent (increasing flow area) section allows the gases to reach supersonic velocity within the divergent section. Additional thrust is generated by the higher resulting exhaust velocity. Thrust was most commonly increased in turbojets with water/methanol injection or afterburning . Some engines used both methods. Liquid injection

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744-480: 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 later concentrated on the simpler centrifugal compressor only, for a variety of practical reasons. A Whittle engine was the first turbojet to run, the Power Jets WU , on 12 April 1937. It

806-577: A two-way average of 446.63 km/h (277.52 mph) in September 1965. Five weeks later, Goodyear hit back against Firestone with Lee Breedlove . While recordkeeping has not been as extensive, a report in 1974 confirmed that a record was held by Lee Breedlove, the wife of then overall record holder Craig Breedlove , who piloted her husband's Spirit of America – Sonic I to a record 496.492 km/h (308.506 mph) in 1965. According to author Rachel Kushner , Craig Breedlove had talked Lee into taking

868-634: A vehicle of the North American Eagle Project running at the Alvord Desert, raised the women's four-wheel land speed class record with an official run of 632.40 km/h (392.954 mph), surpassing Breedlove's 48-year-old record. Combs continued with the North American Eagle Project, whose ongoing target is the overall land speed record; as part of that effort, Combs was killed, on August 27, 2019, during an attempt to raise

930-677: Is a call for the newer models being developed to advance its control systems to implement the newest knowledge from the areas of automation, so increase its safety and effectiveness. Land speed record The land speed record ( LSR ) or absolute land speed record is the highest speed achieved by a person using a vehicle on land. By a 1964 agreement between the Fédération Internationale de l'Automobile (FIA) and Fédération Internationale de Motocyclisme (FIM), respective governing bodies for racing in automobiles and motorcycles (two or three wheels), both bodies recognise as

992-413: Is a component of a turbojet used to divert air into the intake, in front of the accessory drive and to house the starter motor. An intake, or tube, is needed in front of the compressor to help direct the incoming air smoothly into the rotating compressor blades. Older engines had stationary vanes in front of the moving blades. These vanes also helped to direct the air onto the blades. The air flowing into

1054-523: Is greater than atmospheric pressure, and extra terms must be added to the above equation to account for the pressure thrust. The rate of flow of fuel entering the engine is very small compared with the rate of flow of air. If the contribution of fuel to the nozzle gross thrust is ignored, the net thrust is: F N = m ˙ a i r ( V j − V ) {\displaystyle F_{N}={\dot {m}}_{air}(V_{j}-V)} The speed of

1116-568: Is modelled approximately by the Brayton cycle . The efficiency of a gas turbine is increased by raising the overall pressure ratio, requiring higher-temperature compressor materials, and raising the turbine entry temperature, requiring better turbine materials and/or improved vane/blade cooling. It is also increased by reducing the losses as the flow progresses from the intake to the propelling nozzle. These losses are quantified by compressor and turbine efficiencies and ducting pressure losses. When used in

1178-585: Is more commonly by use of a turboshaft engine, a development of the gas turbine engine where an additional turbine is used to drive a rotating output shaft. These are common in helicopters and hovercraft. Turbojets were widely used for early supersonic fighters , up to and including many third generation fighters , with the MiG-25 being the latest turbojet-powered fighter developed. As most fighters spend little time traveling supersonically, fourth-generation fighters (as well as some late third-generation fighters like

1240-508: Is standardized over a course measuring either 1 kilometre (0.62 mi) or 1 mile (1.6 km), averaged over two runs with flying start (commonly called "passes") going in opposite directions within one hour. A new record mark must exceed the previous one by at least one percent to be validated. Until 1829 the fastest land transport was by horse. The first regulator was the Automobile Club de France , which proclaimed itself arbiter of

1302-613: The F-111 and Hawker Siddeley Harrier ) and subsequent designs are powered by the more efficient low-bypass turbofans and use afterburners to raise exhaust speed for bursts of supersonic travel. Turbojets were used on Concorde and the longer-range versions of the Tu-144 which were required to spend a long period travelling supersonically. Turbojets are still common in medium range cruise missiles , due to their high exhaust speed, small frontal area, and relative simplicity. The first patent for using

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1364-679: The Gloster Meteor , entered service in 1944, towards the end of World War II , the Me 262 in April and the Gloster Meteor in July. Only about 15 Meteor saw WW2 action but up to 1400 Me 262s were produced, with 300 entering combat, delivering the first ground attacks and air combat victories of jet planes. Air is drawn into the rotating compressor via the intake and is compressed to a higher pressure before entering

1426-571: The Heinkel HeS 3 ), or an axial compressor (as in the Junkers Jumo 004 ) which gave a smaller diameter, although longer, engine. By replacing the propeller used on piston engines with a high speed jet of exhaust, higher aircraft speeds were attainable. One of the last applications for a turbojet engine was Concorde which used the Olympus 593 engine. However, joint studies by Rolls-Royce and Snecma for

1488-515: The North American XB-70 Valkyrie , each feeding three engines with an intake airflow of about 800 pounds per second (360 kg/s). The turbine rotates the compressor at high speed, adding energy to the airflow while squeezing (compressing) it into a smaller space. Compressing the air increases its pressure and temperature. The smaller the compressor, the faster it turns. The (large) GE90-115B fan rotates at about 2,500 RPM, while

1550-479: The Rolls-Royce Welland and Rolls-Royce Derwent , and by 1949 the de Havilland Goblin , being type tested for 500 hours without maintenance. It was not until the 1950s that superalloy technology allowed other countries to produce economically practical engines. Early German turbojets had severe limitations on the amount of running they could do due to the lack of suitable high temperature materials for

1612-424: The Tu-144 , also used afterburners as does Scaled Composites White Knight , a carrier aircraft for the experimental SpaceShipOne suborbital spacecraft. Reheat was flight-trialled in 1944 on the W.2/700 engines in a Gloster Meteor I . The net thrust F N {\displaystyle F_{N}\;} of a turbojet is given by: F N = ( m ˙

1674-407: The de Havilland Vampire . It was around this time that de Havilland purchased Halford's company and set him up as the chairman of the de Havilland Engine Company , with the engine name changing from H-1 to "Goblin", while the new H-2 design became the "Ghost" – de Havilland jet and rocket engines were all named after spectral apparitions . In July 1943, one of the two H-1s then available (actually

1736-763: The British register. As of December 2014, three Goblin-powered de Havilland Vampires remain airworthy in North America. N115DH is owned by the World Heritage Air Museum., C-FJRH is operated under the Jet Aircraft Museum in Ontario, Canada. and N593RH is owned by Vampire Aviation LLC. As of November 2015, three Goblin-powered de Havilland Vampires remain airworthy in South Africa. Serial number 276 and 277 are in

1798-402: The FIA and other car-racing organisations, Guinness World Records does recognize gender-based land speed records. In 1906, Dorothy Levitt broke the women's world speed record for the flying kilometer, recording a speed of 154 km/h (96 mph) and receiving the sobriquet the "Fastest Girl on Earth". She drove a six-cylinder Napier motorcar , a 75 kW (100 hp) development of

1860-400: The FIA in 1947. Controversy arose in 1963: Spirit of America was not recognized due to its being a three-wheeler (leading the Fédération Internationale de Motocyclisme to certify it as a three-wheel motorcycle record when the FIA refused) and not wheel-driven so the FIA introduced a special jet and rocket propelled class . No holder of the absolute record since has been wheel-driven. In

1922-775: The K5, in a speed trial in Blackpool . in 1963, Paula Murphy drove a Studebaker Avanti to 262 km/h (163 mph) at the Bonneville Salt Flats as part of Andy Granatelli 's attempt on the overall record. In 1964, she was asked by the tire company Goodyear to try to improve her own record, which she raised to 364.31 km/h (226.37 mph) in Walt Arfons 's jet dragster Avenger . The rival tire company Firestone and Art Arfons hit back against Goodyear and Walt Arfons when Betty Skelton drove Art's Cyclops to achieve

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1984-619: The Mk. 35 export version. The Goblin was the primary engine of the de Havilland Vampire , and was to have been the engine for the F-80 Shooting Star (as the Allis-Chalmers J36 ) before that design switched engines due to production delays at Allis-Chalmers. The Goblin also powered the Saab 21R fighter, Fiat G.80 trainer and the de Havilland DH 108 "Swallow" experimental aircraft. The Goblin

2046-510: The SA Air Force Museum and the third is at Wonderboom Airport. Data from Smith Related development Related lists Turbojet 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-powered", this

2108-472: The U.S. and Australia, record runs are often done on salt flats , so the cars are often called salt cars. The FIA does not recognize separate men's and women's land speed records, because the records are set using motorized vehicles , and not muscle-powered vehicles , so the gender of the driver does not matter; however, unofficial women's records have long been claimed, seemingly starting with Dorothy Levitt 's 1906 record in Blackpool , England, and, unlike

2170-489: The absolute LSR whatever is the highest speed record achieved across any of their various categories. While the three-wheeled Spirit of America set an FIM-validated LSR in 1963, all subsequent LSRs are by vehicles in FIA Category C ("Special Vehicles") in either class JE (jet engine) or class RT (rocket powered). FIA LSRs are officiated and validated by its regional or national affiliate organizations. Speed measurement

2232-464: The aircraft decreases the efficiency of the engine because it has been compressed, but then does not contribute to producing thrust. Compressor types used in turbojets were typically axial or centrifugal. Early turbojet compressors had low pressure ratios up to about 5:1. Aerodynamic improvements including splitting the compressor into two separately rotating parts, incorporating variable blade angles for entry guide vanes and stators, and bleeding air from

2294-554: The car out for a record attempt in order to monopolize the salt flats for the day and block one of his competitors from making a record attempt. In 1976, the women's absolute record was set by Kitty O'Neil , in the jet-powered, three-wheeled SMI Motivator , at the Alvord Desert . Held back by her contract with a sponsor and using only 60 percent of her car's power, O'Neil reached an average speed of 825.127 km/h (512.710 mph). On October 9, 2013, driver Jessi Combs , in

2356-410: The combustion chamber. Fuel is mixed with the compressed air and burns in the combustor. The combustion products leave the combustor and expand through the turbine where power is extracted to drive the compressor. The turbine exit gases still contain considerable energy that is converted in the propelling nozzle to a high speed jet. The first turbojets, used either a centrifugal compressor (as in

2418-432: The combustor and pass through to the turbine in a continuous flowing process with no pressure build-up. Instead, a small pressure loss occurs in the combustor. The fuel-air mixture can only burn in slow-moving air, so an area of reverse flow is maintained by the fuel nozzles for the approximately stoichiometric burning in the primary zone. Further compressed air is introduced which completes the combustion process and reduces

2480-421: The compressor enabled later turbojets to have overall pressure ratios of 15:1 or more. After leaving the compressor, the air enters the combustion chamber. The burning process in the combustor is significantly different from that in a piston engine . In a piston engine, the burning gases are confined to a small volume, and as the fuel burns, the pressure increases. In a turbojet, the air and fuel mixture burn in

2542-401: The compressor is passed through these to keep the metal temperature within limits. The remaining stages do not need cooling. In the first stage, the turbine is largely an impulse turbine (similar to a pelton wheel ) and rotates because of the impact of the hot gas stream. Later stages are convergent ducts that accelerate the gas. Energy is transferred into the shaft through momentum exchange in

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2604-521: The compressor stage. Well-known examples are the Concorde and Lockheed SR-71 Blackbird propulsion systems where the intake and engine contributions to the total compression were 63%/8% at Mach 2 and 54%/17% at Mach 3+. Intakes have ranged from "zero-length" on the Pratt & Whitney TF33 turbofan installation in the Lockheed C-141 Starlifter , to the twin 65 feet (20 m) long, intakes on

2666-506: The engine, at the expense of being slightly longer and requiring a longer power shaft between the turbine and compressor. Although it eliminated the Whittle-style "folding", the Goblin was still a compact design. The H-1 first ran on 13 April 1942 and quickly matured to produce its full design thrust within two months. It first flew on 5 March 1943 in the Gloster Meteor , and on 26 September in

2728-584: The exhaust powered a single-stage axial turbine. Compared to Whittle designs, the H-1 was cleaned up in that it used a single-sided compressor with the inlet at the front, and a straight-through layout with the combustion chambers exhausting straight onto the turbine. Whittle's designs such as the Power Jets W.2 used a reverse-flow layout that piped the hot air back to the middle of the engine, in order to "fold" it and reduce its length. The straight-through design simplified

2790-578: The four-wheel record. In late June 2020, the Guinness Book of Records reclassified the August 27, 2019 speed runs as meeting its requirements, and Combs was posthumously credited with the record at 841.338 km/h (522.783 mph), noting she was the first to break the record in 40 years. Craig Breedlove 's mark of 407.447 miles per hour (655.722 km/h), set in Spirit of America in September 1963,

2852-475: The high-temperature materials used in their turbosuperchargers during World War II. Water injection was a common method used to increase thrust, usually during takeoff, in early turbojets that were thrust-limited by their allowable turbine entry temperature. The water increased thrust at the temperature limit, but prevented complete combustion, often leaving a very visible smoke trail. Allowable turbine entry temperatures have increased steadily over time both with

2914-441: The introduction of superior alloys and coatings, and with the introduction and progressive effectiveness of blade cooling designs. On early engines, the turbine temperature limit had to be monitored, and avoided, by the pilot, typically during starting and at maximum thrust settings. Automatic temperature limiting was introduced to reduce pilot workload and reduce the likelihood of turbine damage due to over-temperature. A nose bullet

2976-401: The jet V j {\displaystyle V_{j}\;} must exceed the true airspeed of the aircraft V {\displaystyle V\;} if there is to be a net forward thrust on the airframe. The speed V j {\displaystyle V_{j}\;} can be calculated thermodynamically based on adiabatic expansion . The operation of a turbojet

3038-402: The opposite way to energy transfer in the compressor. The power developed by the turbine drives the compressor and accessories, like fuel, oil, and hydraulic pumps that are driven by the accessory gearbox. After the turbine, the gases expand through the exhaust nozzle producing a high velocity jet. In a convergent nozzle, the ducting narrows progressively to a throat. The nozzle pressure ratio on

3100-739: The prototype Vampire. Allis-Chalmers was selected to produce the engine in the US as the J36 , but ran into lengthy delays. Instead, the Allison J33 , developed by General Electric as the I-40 (their greatly improved 4,000 lbf (18 kN) version of the J31 , itself based on Whittle's W.1 ), was selected for the production P-80A. Goblin engines are preserved and on display at several museums including: As of June 2011, two Goblin-powered de Havilland Vampires remain airworthy on

3162-721: The record in about 1902. Different clubs had different standards and did not always recognize the same world records until 1924, when the Association Internationale des Automobile Clubs Reconnus (AIACR) introduced new regulations: two passes in opposite directions (to negate the effects of wind) averaged with a maximum of 30 minutes (later more) between runs, average gradient of the racing surface not more than 1 percent, timing gear accurate within 0.01sec, and cars must be wheel-driven . National or regional auto clubs (such as AAA and SCTA ) had to be AIACR members to ensure records would be recognized. The AIACR became

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3224-576: The spare engine intended as a backup for the one installed in the Vampire prototype ) was sent to the United States , where it was selected to become the primary engine of the Lockheed P-80 Shooting Star . This engine was fitted to the prototype P-80, which first flew on 9 January 1944. The engine was later accidentally destroyed in ground testing, and was replaced by the only remaining H-1 from

3286-468: The supersonic airliner, in terms of miles per gallon, compared to subsonic airliners at Mach 0.85 (Boeing 707, DC-8) was relatively small. This is because the large increase in drag is largely compensated by an increase in powerplant efficiency (the engine efficiency is increased by the ram pressure rise which adds to the compressor pressure rise, the higher aircraft speed approaches the exhaust jet speed increasing propulsive efficiency). Turbojet engines had

3348-446: The temperature of the combustion products to a level which the turbine can accept. Less than 25% of the air is typically used for combustion, as an overall lean mixture is required to keep within the turbine temperature limits. Hot gases leaving the combustor expand through the turbine. Typical materials for turbines include inconel and Nimonic . The hottest turbine vanes and blades in an engine have internal cooling passages. Air from

3410-535: The thrust from a turbojet engine. It was flown by test pilot Erich Warsitz . The Gloster E.28/39 , (also referred to as the "Gloster Whittle", "Gloster Pioneer", or "Gloster G.40") made the first British jet-engined flight in 1941. It was designed to test the Whittle jet engine in flight, and led to the development of the Gloster Meteor. The first two operational turbojet aircraft, the Messerschmitt Me 262 and then

3472-412: The turbines would overheat, the lubricating oil would leak from the bearing cavities, the rotor thrust bearings would skid or be overloaded, and ice would form on the nose cone. The air from the compressor, called secondary air, is used for turbine cooling, bearing cavity sealing, anti-icing, and ensuring that the rotor axial load on its thrust bearing will not wear it out prematurely. Supplying bleed air to

3534-464: The turbines. British engines such as the Rolls-Royce Welland used better materials giving improved durability. The Welland was type-certified for 80 hours initially, later extended to 150 hours between overhauls, as a result of an extended 500-hour run being achieved in tests. General Electric in the United States was in a good position to enter the jet engine business due to its experience with

3596-439: Was initially considered unofficial. The vehicle breached the FIA regulations on two grounds: it had only three wheels, and it was not wheel-driven , since its jet engine did not supply power to its axles. Some time later, the Fédération Internationale de Motocyclisme (FIM) created a non-wheel-driven category, and ratified Spirit of America ' s time for this mark. On July 17, 1964, Donald Campbell 's Bluebird CN7 posted

3658-419: Was later scaled up as the larger de Havilland Ghost , with the model numbers continuing from the last marks of the Goblin. Design of the engine was carried out by Frank Halford at his London consulting firm starting in April 1941. It was based on the overall design pattern pioneered by Frank Whittle , using a centrifugal compressor providing compressed air to sixteen individual combustion chambers, from which

3720-424: Was liquid-fuelled. Whittle's team experienced near-panic during the first start attempts when the engine accelerated out of control to a relatively high speed despite the fuel supply being cut off. It was subsequently found that fuel had leaked into the combustion chamber during pre-start motoring checks and accumulated in pools, so the engine would not stop accelerating until all the leaked fuel had burned off. Whittle

3782-577: Was tested on the Power Jets W.1 in 1941 initially using ammonia before changing to water and then water-methanol. A system to trial the technique in the Gloster E.28/39 was devised but never fitted. An afterburner or "reheat jetpipe" is a combustion chamber added to reheat the turbine exhaust gases. The fuel consumption is very high, typically four times that of the main engine. Afterburners are used almost exclusively on supersonic aircraft , most being military aircraft. Two supersonic airliners, Concorde and

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3844-479: Was unable to interest the government in his invention, and development continued at a slow pace. In Germany, Hans von Ohain patented a similar engine in 1935. His design, an axial-flow engine, as opposed to Whittle's centrifugal flow engine, was eventually adopted by most manufacturers by the 1950s. On 27 August 1939 the Heinkel He 178 , powered by von Ohain's design, became the world's first aircraft to fly using

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