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102-488: The de Havilland Gyron Junior is a military turbojet engine design of the 1950s developed by the de Havilland Engine Company and later produced by Bristol Siddeley . The Gyron Junior was a scaled-down derivative of the de Havilland Gyron . The Gyron Junior was a two-fifths flow scale version of the existing Gyron engine. It started as Project Study number 43 in 1954 and the first prototype ran in August 1955. It powered

204-416: 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

306-423: A braking parachute . The Tu-144 was not fitted with any reverse thrust capabilities, and so the parachute was used as the sole alternative. A prototype without passenger seats was fitted with ejection seats for pilots. The aircraft was designed for a 30,000-hour service life over 15 years. Airframe heating and the high temperature properties of the primary structural materials, which were aluminium alloys , set

408-612: A cargo aircraft until the cancellation of the Tu-144 program in 1983. The Tu-144 was later used by the Soviet space program to train pilots of the Buran spacecraft, and by NASA for supersonic research until 1999. The Tu-144 made its final flight on 26 June 1999 and surviving aircraft were put on display in Russia, the former Soviet Union and Germany, or into storage. Given the vast size of

510-708: A Tu-144 as a testbed for NASA's High Speed Commercial Research program, which was intended to design a second-generation supersonic jetliner called the High Speed Civil Transport . In 1995, Tu-144D No. 77114 (with only 82.5 hours of flight time) was taken out of storage and after extensive modification at a cost of US$ 350   million, designated the Tu-144LL (where LL is a Russian abbreviation for Flying Laboratory, Russian : Летающая Лаборатория , Letayushchaya Laboratoriya ). The aircraft made 27 flights in Russia during 1996 and 1997. Though regarded as

612-622: A broken ramp delayed departure half an hour. On arrival to Alma-Ata, the Tu-144 was towed back and forth for 25 minutes to align it correctly with the exit ramp. Flight testing time logged on the prototype (68001) was 180 hours; flight testing time until the completion of state acceptance tests was 1509 hours, followed with 835 hours of flight time of service tests until the commencement of passenger service. The Tu-144S went into service on 26 December 1975, flying mail and freight between Moscow and Alma-Ata in preparation for passenger services, which commenced on 1 November 1977. The type certificate

714-443: A conversation only with difficulty, and those seated two seats apart could not hear each other even when screaming and had to pass hand-written notes instead. Noise in the rear of the cabin was described as unbearable. The Tu-144 programme was cancelled by a Soviet government decree on 1 July 1983 that also provided for future use of the remaining Tu-144 aircraft as airborne laboratories. In 1985, Tu-144D were used to train pilots for

816-585: 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

918-542: 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

1020-420: A range in excess of 7,000 km (4,300 mi; 3,800 nmi) range were never implemented. The engine intakes had variable intake ramps and bypass flaps with positions controlled automatically to suit the engine airflow. They were very long to help prevent surging; twice as long as those on Concorde. Jean Rech (Sud Aviation) states the need for excessive length was based on the misconception that length

1122-459: 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

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1224-411: 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

1326-405: 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,

1428-512: A speed of around 2,200 kilometres per hour (1,400 mph) ( Mach 2). The Tu-144 first went supersonic on 5 June 1969, four months before Concorde, and on 26 May 1970 became the world's first commercial transport to exceed Mach 2. Reliability and developmental issues restricted the viability of the Tu-144 for regular use; these factors, together with repercussions of the 1973 Paris Air Show Tu-144 crash , projections of high operating costs, and rising fuel prices and environmental concerns outside

1530-504: A technical success, the project was cancelled for lack of funding in 1999. This aircraft was reportedly sold in 2001 online, but the aircraft sale did not proceed. Tejavia Systems, the company handling the transaction, reported that the deal was not signed as the replacement Kuznetsov NK-321 engines also used in a Tupolev Tu-160 bomber were military hardware and the Russian government would not allow them to be exported. In 2003, after

1632-513: 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

1734-512: 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

1836-494: 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

1938-487: 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

2040-446: A way to switch it off so the siren stayed on throughout the remaining 75 minutes of the flight. Eventually, the captain ordered the navigator to borrow a pillow from the passengers and stuff it inside the siren's horn. After all the suspense, all landing gear extended and the aircraft landed. A subsequent flight of Tu-144 on around 30 May 1978, not long before the type was withdrawn from passenger service, involved valve failure on one of

2142-576: A week later another aircraft was lost after an uncontained engine failure. This last accident brought to an end the use of Gyron Junior. Two Gyron Juniors, with afterburners, were also used on the Bristol 188 Mach 2 supersonic research aircraft. The 188 was originally intended to have the Rolls-Royce Avon but the half ton lighter Gyron Junior was substituted in June 1957. This engine was one of

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2244-478: A week, despite there being eight Tu-144S certified aircraft available and a number of other routes suitable for supersonic flights, suggesting that the Aeroflot decision-makers had little confidence in the Tu-144 commercial viability when passenger service began in 1977. In the late 1970s, Soviet insiders were intensely hopeful in conversations with Western counterparts of reintroducing Tu-144 passenger service for

2346-410: 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. TU-144 The Tupolev Tu-144 ( Russian : Tyполев Ту-144 ; NATO reporting name : Charger ) is a Soviet supersonic passenger airliner designed by Tupolev in operation from 1968 to 1999. The Tu-144

2448-413: 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

2550-425: Is apparent even in outward timing: the 1963 government decree launching the Tu-144 programme defined that the Tu-144 should fly in 1968; it first flew on the last day of 1968 (31 December) to fulfill government goals set five years earlier. Sixteen airworthy Tu-144 airplanes were built: Although its last commercial passenger flight was in 1978, production of the Tu-144 did not cease until 1983, when construction of

2652-523: 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

2754-573: 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

2856-589: 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

2958-564: The 1973 oil crisis did not directly impact decision-making processes within the Soviet Union, the expansion of Soviet air travel in the late 1970s made the supply of aviation fuel a growth constraint, and it was obvious that potential Western buyers were heavily dissuaded by high fuel prices. By the late 1970s, Soviet promotional efforts shifted to the Ilyushin Il-86 , a more economically efficient jumbo jet that went on to become

3060-454: The 1980 Moscow Olympic games , even perhaps for flights to Western Europe, given the aircraft's high visibility, but apparently the technical condition of the aircraft weighed against such re-introduction even for token flights. There were unprecedented Soviet requests for Western technological aid with the development of the Tu-144. In 1977, the USSR approached Lucas Industries , a designer of

3162-669: The Blackburn Buccaneer S.1 twin-engined Naval strike aircraft. The engine was rather unreliable and considered short of thrust. The later Buccaneer S.2 used the more powerful Rolls-Royce Spey engine. The engine had variable inlet guide vanes, as used on many other engines, necessary for accelerating from idle to high thrust. However, on the Gyron Junior, positioning of the vanes was not reliable and could cause surging which, in turn, could prevent accelerating to higher thrust levels. A possibly unique feature on this engine

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3264-601: The Communist revolution , as was duly noted in Soviet officials' speeches delivered at the airport before the inaugural flight – whether the aircraft was actually ready for passenger service was deemed of secondary importance. Even the outward details of the inaugural Tu-144 flight betrayed the haste of its introduction into service: several ceiling panels were ajar, service trays stuck, window shades dropped without being pulled, reading lights did not work, not all toilets worked and

3366-621: 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

3468-704: 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

3570-588: 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

3672-527: 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

3774-488: 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

3876-424: 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 ˙

3978-570: The raw material . Cracks formed at the defects at load levels below that which the part was expected to withstand. Once a crack started to grow, it spread quickly over many metres, with no crack-arresting design feature to stop it. In 1976, during repeat-load and static testing at TsAGI (Russia's Central Aerohydrodynamic Institute ), a Tu-144S airframe cracked at 70% of the design flight load with cracks running many metres in both directions from their origin. Two Tu-144S airframes suffered structural failures during laboratory testing just prior to

4080-517: The Cold War period, the Soviet Union was intent on not just matching, but surpassing Western advancements, particularly in aerospace technology. The idea of the West getting ahead and leaving the Soviet Union behind was unthinkable. The directive from Nikita Khrushchev , the leader of the Soviet Union at that time, was clear: not only prevent the West from getting ahead, but also compete fiercely, even to

4182-416: The Concorde (M2.15 vs. M2.04). Concorde used an electronic engine control package from Lucas , which Tupolev was not permitted to purchase for the Tu-144 as it could also be used on military aircraft. Concorde's designers used fuel as coolant for the cabin air conditioning and for the hydraulic system (see Concorde for details). Tupolev also used fuel/hydraulic heat exchangers , but used cooling turbines for

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4284-534: The NK-144 high SFC gave a limited range of about 2,500 km (1,600  mi ; 1,300  nmi ), far less than Concorde. A maximum speed of 2,443 km/h (1,518 mph; 1,319 kn) (Mach 2.35) was reached with afterburning. Afterburners were added to Concorde to meet its take-off thrust requirement and were not necessary for supersonic cruise; the Tu-144 used maximum afterburner for take-off and minimum for cruise. The Tu-144S , of which nine were produced,

4386-468: The Soviet Buran space shuttle. In 1986–1988 Tu-144D No. 77114, built in 1981, was used for medical and biological research of high-altitude atmosphere radiological conditions. Further research was planned but not completed, due to lack of funding. In the early 1990s, Judith de Paul, and her company IBP Aerospace brokered an agreement with Tupolev, NASA , Rockwell and later Boeing . They offered

4488-402: The Soviet Union, caused foreign customer interest to wane. The Tu-144 was introduced into commercial service with Aeroflot between Moscow and Alma-Ata on 26 December 1975 and starting 1 November 1977 passenger flights began; it was withdrawn less than seven months later after a new Tu-144 variant crash-landed during a test flight on 23 May 1978. The Tu-144 remained in commercial service as

4590-637: The Soviet Union, supersonic travel was seen as economically feasible, especially for government employees travelling between Moscow and Siberian cities. Flying was the only practical alternative to week-long rail journeys, and supersonic transport could significantly cut travel times. While the idea of SSTs was controversial in the West due to noise and environmental pollution concerns, the Soviet Union planned to continue with their development, largely for its long Siberian and Central Asian routes. With ample airspace, flight corridors were likely to avoid built-up areas. Even if international landing rights were not granted,

4692-407: The Tu-144 could still be used for domestic and regional flights. Aeroflot, the flag carrier of the Soviet Union, had an extensive network of interconnected airfields and increasing international reach, with hopes of extending flights to Sydney, Australia. Initial estimates suggested that 20 Tu-144s would suffice for Aeroflot's domestic and international needs. Given the geopolitical climate during

4794-511: The Tu-144 entering passenger service. The problem, discovered in 1976, may have been known prior to this testing; a large crack was discovered in the airframe of the prototype Tu-144 (aircraft 68001) during a stopover in Warsaw following its appearance at the 1971 Paris Air Show. Polish sources say the crack was discovered after the aircraft made an emergency landing due to the failure of both left-hand engines; however, an Aeroflot spokesperson denied

4896-473: The World's Aircraft 1962-63. Related development Comparable engines Related lists Turbojet engine 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

4998-464: 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

5100-415: The aircraft in the 1973 Paris Air Show Tu-144 crash . This conclusion was supported by some of the designers involved in the aircraft's development. Vadim Razumikhin wrote that the load factor experienced by the plane at the moment of the break-up was less than the design limit. If the stress tests had been conducted earlier, the disaster may have been averted. Eventually, the airframe was strengthened and

5202-426: The aircraft would have to land on the right gear alone, at a landing speed of over 300 km/h (190 mph; 160 kn). Due to expected political fallout, Soviet leader Leonid Brezhnev was personally notified of what was going on in the air. With the accumulated failures, an alarm siren went off immediately after takeoff, with sound and volume similar to that of a civil defence warning. The crew could not figure

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5304-561: The airframe to withstand damage, firefighting equipment, including warning devices and lightning protection, emergency power supply, and landing gear spray guards (a.k.a. water deflectors or " mud flaps " that increase engine efficiency when taking off from wet airstrips). These requests were denied after the British government vetoed them on the ground that the same technologies, if transferred, could be also employed in Soviet bombers. Soviet approaches were also reported in British tabloids at

5406-460: The cabin air. The Tu-144 prototype was a full-scale demonstrator aircraft with the very different production aircraft being developed in parallel. The MiG-21I (1968; Izdeliye 21–11; "Analog") I = Imitator ("Simulator") was a testbed for the wing design of the Tu-144 but came too late to provide inputs for the first prototype. The findings of the MiG-21I led to the completely redesigned wing of

5508-417: The cockpit and increased lift at low speeds. Moving the elevons downward in a delta-wing aircraft increases the lift, but also pitches its nose downward. The canards cancel out this nose-downwards moment , thus reducing the landing speed of the production Tu-144s to 315–333 km/h (196–207 mph; 170–180 kn). Along with early Tu-134s , the Tu-144 was one of the last commercial aircraft with

5610-410: 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

5712-432: 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

5814-421: 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

5916-401: 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

6018-536: 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

6120-455: The condition of the aircraft and make a joint decision on whether it could be released into flight. Subsequently, flight cancellations became less common, as several Tu-144s were docked at Moscow's Domodedovo International Airport . Tu-144 pilot Aleksandr Larin remembers a troublesome flight around 25 January 1978. The flight with passengers suffered the failure of 22 to 24 onboard systems. Seven to eight systems failed before takeoff, but given

6222-498: The control system was modified to prevent overstressing the aircraft. Tu-144 suffered from a rush in the design process to the detriment of thoroughness and quality. According to Concorde technical flight manager Brian Calvert, "the rush to get [Tu-144] airborne exacted a heavy penalty later". Concorde's first flight was originally scheduled for February 1968, but was pushed back several times until March 1969 in order to iron out problems and test components more thoroughly. The rush

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6324-572: The country's flagship airliner. Moon notes that in 1976, Aeroflot was promoting the Il-86 over the Tu-144, despite the latter's incipient and long-awaited entry into service. G.A. Cheryomukhin, an aerodynamics engineer who took part in the design and certification of Tu-144, wrote that the Ministry of Civil Aviation was concerned that the continuation and expansion of the SST's operation would have forced

6426-441: The damage and disputed the circumstances of the landing. Later the same year, a test airframe was subjected to a test simulating the temperatures and pressures occurring during a flight. High skin temperatures of 110–130 °C (230–270 °F) were caused by kinetic heating when the boundary layer air reached 150–180 °C (300–360 °F) during cruise. The Tu-144 was placed in an environmental chamber and heated to simulate

6528-521: The design was approved by the Council of Ministers . The plan called for five flying prototypes to be built in four years, with the first aircraft to be ready in 1966. Despite the similarity in appearance of the Tu-144 to the Anglo-French supersonic aircraft (which earned it the nickname "Concordski"), there were significant differences between the two aircraft. The Tu-144 is bigger and faster than

6630-436: The engine control system for Concorde, requesting help with the design of the electronic management system of the Tu-144 engines, and also asked BAC-Aérospatiale for assistance in improving the Tu-144 air intakes. (The design of air intakes' variable geometry and their control system was one of the most intricate features of Concorde, contributing to its fuel efficiency. Over half of the wind-tunnel time during Concorde development

6732-538: The extent of leapfrogging their technological advancements, if necessary. The aircraft was seen as a formidable challenge to the United States' dominance in the field of civil aviation. The Soviet government published the concept of the Tu-144 in an article in the January 1962 issue of the magazine Technology of Air Transport . The air ministry started development of the Tu-144 on 26 July 1963, 10 days after

6834-404: The final airframe was stopped and left partially complete. The last production aircraft, Tu-144D number 77116, was not completed and was left derelict for many years on Voronezh East airfield . There was at least one ground test airframe for static testing in parallel with the development of prototype 68001. The introduction of the Tu-144 into passenger service was timed to the 60th anniversary of

6936-465: The final blow, which resulted in the cancellation of the project by the Ministry of Aviation Industry and the Ministry of Civil Aviation. One of the Tu-144Ds (77114, a.k.a. aircraft 101) suffered a crack across the bottom panel of its wing. Global trends facilitated the transition of jet transportation from a luxury available only to the elite, to a widespread form of mass transportation. Although

7038-404: The first with continuously variable thrust up to full reheat; others increased thrust in discrete steps. The programme was terminated early without achieving the high-speed high-temperature trials that had been intended. Limitations included poor fuel consumption of the Gyron Junior and engine surging. Fuel limitations restricted the time spent at its maximum speed, Mach 1.95, to a few minutes. This

7140-485: The flight schedule. The most frequent sources of trouble were the flight instruments, navigation gear, radios, and autopilot . After the inaugural flight, two subsequent flights during the next two weeks were cancelled and the third flight rescheduled. The official reason given by Aeroflot for cancellation was bad weather at Alma-Ata; however when the journalist called the Aeroflot office in Alma-Ata about local weather,

7242-452: The following aircraft. While both Concorde and the Tu-144 prototype had ogival delta wings, the Tu-144's wing lacked Concorde's conical camber . Production Tu-144s replaced this wing with a double delta wing including spanwise and chordwise camber. They also added two small retractable surfaces called a moustache canard , with fixed double-slotted leading-edge slats and retractable double-slotted flaps . These were fitted just behind

7344-461: The fuel tanks. A problem for passengers was the very high noise level inside the cabin, measuring at least 90–95 dB on average. The noise came from the engines; unlike Concorde, it could only sustain supersonic speeds using afterburners continuously. In addition, the active heat insulation system used for the air conditioning, which used the flow of spent cabin air, was described as excessively noisy. Passengers seated next to each other could have

7446-475: 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

7548-441: 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

7650-401: 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

7752-411: The large number of foreign TV and radio journalists and also other foreign notables aboard the flight, it was decided to proceed with the flight to avoid the embarrassment of cancellation. After takeoff, failures continued to multiply. While the aircraft was supersonic en route to the destination airport, Tupolev bureau's crisis centre predicted that the front and left landing gear would not extend and that

7854-582: The maximum speed at Mach 2.2. 15% by weight was titanium and 23% non-metallic materials. Titanium or stainless steel were used for the leading edges, elevons, rudder and the rear fuselage engine-exhaust heat shield . SSTs for M2.2 had been designed in the Soviet Union before Tupolev was tasked with developing one. Design studies for the Myasishchev SST had shown that a cruise specific fuel consumption (SFC) of not more than 1.2 kg/kgp hr would be required. The only engine available in time with

7956-458: The more efficient Kolesov RD-36-51 turbojet engines, which also increased the maximum cruising speed to Mach 2.15. There were only 103 scheduled flights before the Tu-144 was removed from commercial service. During 102 flights and 181 hours of freight and passenger flight time, the Tu-144S suffered more than 226 failures; 80 of them occurred in flight and 80 of them were severe enough to affect

8058-434: The office said that the weather there was perfect and one aircraft had already arrived that morning. Subsequent and significant documented Tu-144 failures included insufficient cabin pressurisation in flight on 27 December 1977, a landing gear switch fault on 29 January 1978 that indicated that the gear was lowered when it was in fact retracted, and engine-exhaust duct overheating causing the flight to be aborted and returned to

8160-402: 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

8262-515: The required thrust and suitable for testing and perfecting the aircraft was the afterburning Kuznetsov NK-144 turbofan with a cruise SFC of 1.58 kg/kgp hr. Development of an alternative engine to meet the SFC requirement, a non-afterburning turbojet, the Kolesov RD-36-51 A, began in 1964. It took a long time for this engine to achieve acceptable SFC and reliability. In the meantime

8364-484: The retirement of Concorde, there was renewed interest from several wealthy individuals who wanted to use the Tu-144LL for a transatlantic record attempt, despite the high cost of a flight readiness overhaul even if military authorities would authorize the use of NK-321 engines outside Russian Federation airspace. Only one commercial route, Moscow to Alma-Ata (now Almaty ), was ever used and flights were limited to one

8466-451: The skin getting hot quickly, during acceleration to cruising speed, while the underlying structure took a while to reach its equilibrium temperature. This thermal effect caused internal stresses and the situation was reversed while slowing down and descending. The pressure in the cabin, which caused additional stresses, was changed at the same time as the skin heating to simulate climbing to cruise altitude and then descending. Repeatedly cycling

8568-468: 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

8670-411: The takeoff airport on 14 March 1978. Additionally, a metal fatigue problem was discovered in the tip of the aircraft's vertical stabilizer; this was mitigated by adding a titanium doubler plate. Aleksey Tupolev, Tu-144 chief designer, and two USSR vice-ministers (of aviation industry and of civil aviation) had to be personally present at Domodedovo airport before each scheduled Tu-144 departure to review

8772-455: The temperature and pressure, as happened with the aircraft in service, caused fatigue damage and the airframe failed in a similar way to that of the TsAGI load testing. According to Iosif Fridlyander  [ ru ] , an aerospace aluminium and beryllium alloys expert, the Tu-144 design allowed a higher incidence of defects in the alloy structure, leading to the fatal in-air breakup of

8874-446: 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

8976-548: 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

9078-507: The time, such as the Daily Mirror . On 31 August 1980, Tu-144D (77113) suffered an uncontained compressor disc failure in supersonic flight which damaged part of the airframe structure and systems. The crew was able to perform an emergency landing at Engels-2 strategic bomber base. On 12 November 1981, a Tu-144D's RD-36-51 engine was destroyed during bench tests, leading to a temporary suspension of all Tu-144D flights. It became

9180-412: 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

9282-408: 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

9384-672: Was fitted with the Kuznetsov NK-144 A turbofan to address lack of take-off thrust and surge margin. SFC at M2.0 was 1.81 kg/kgp hr. A further improvement, the NK-144V, achieved the required SFC, but too late to influence the decision to use the Kolesov RD-36-51 . The Tu-144D , of which five were produced (plus one uncompleted), was powered by the Kolesov RD-36-51 turbojet with an SFC of 1.22 kg/kgp hr. The range with full payload increased to 5,330 km compared to 6,470 km for Concorde. Plans for an aircraft with

9486-637: Was issued by the USSR Gosaviaregister on 29 October 1977. The passenger service ran a semi-scheduled service until the first Tu-144D experienced an in-flight failure during a pre-delivery test flight, crash-landing on 23 May 1978 with two crew fatalities. The Tu-144's 55th and last scheduled passenger flight occurred on 1 June 1978. An Aeroflot freight-only service recommenced using the new production variant Tu-144D ("D" for Dal'nyaya – "long range") aircraft on 23 June 1979, including longer routes from Moscow to Khabarovsk made possible by

9588-424: 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

9690-437: Was not certain that it could be cooled adequately during afterburner operation. The RD-36-51 had no afterburner. The aircraft was assembled from parts machined from large slabs, many over 19 m (62 ft) long and 0.64 to 1.27 m (2.1 to 4.2 ft) wide. While at the time, this approach was heralded as an advanced feature of the design, it turned out that finished parts contained defects which had not been detected in

9792-561: Was not long enough to achieve the required stabilized temperatures in "thermal soaking" tests. Ref: A de Havilland Gyron Junior is on display at the de Havilland Aircraft Museum , London Colney , Hertfordshire . A D.H Gyron Junior is on public display at East Midlands Aeropark . Also on display at the Gatwick Aviation Museum , Charlwood , Surrey , two running engines can also be found here, fitted to Buccaneer S.1, XN923 . Data from Gunston and Jane's All

9894-443: Was required to attenuate intake distortion. The intakes were to be shortened by 10 feet on the projected Tu-144M . The Kolesov RD-36-51 had an unusual translating plug nozzle as an alternative to a variable con-di nozzle, either of which give the variable area ratio required for the range of nozzle pressures which come from low inlet ram at low speeds to high at Mach 2. A plug nozzle was studied for Concorde but rejected as it

9996-608: Was spent on the design of air intakes and their control system.) In late 1978, the USSR requested a wide range of Concorde technologies, evidently reflecting the broad spectrum of unresolved Tu-144 technical issues. The list included de-icing equipment for the leading edge of the air intakes, fuel-system pipes and devices to improve durability of these pipes, drain valves for fuel tanks, fireproof paints, navigation and piloting equipment, systems and techniques for acoustical loading of airframe and controls (to test against acoustic fatigue caused by high jet-noise environment), ways to reinforce

10098-640: 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

10200-879: Was the world's first commercial supersonic transport aircraft with its prototype 's maiden flight from Zhukovsky Airport on 31 December 1968, two months before the British-French Concorde . The Tu-144 was a product of the Tupolev Design Bureau, an OKB headed by aeronautics pioneer Aleksey Tupolev , and 16 aircraft were manufactured by the Voronezh Aircraft Production Association in Voronezh . The Tu-144 conducted 102 commercial flights , of which only 55 carried passengers, at an average service altitude of 16,000 metres (52,000 ft) and cruised at

10302-485: 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

10404-415: Was valve-controlled cooling air to the turbine blades. The engine had to supply air for the aircraft's boundary layer control system and the resulting thrust loss was unacceptable. To regain the thrust the turbine temperature limit was raised by using turbine blade cooling, selected only with blowing on. In December 1970 a Buccaneer was lost after one engine surged and failed to accelerate on an overshoot and

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