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75-555: Waverider refers in general to aircraft that take advantage of compression lift produced by their own shock waves . The X-51 program was a cooperative effort by the United States Air Force , DARPA , NASA , Boeing , and Pratt & Whitney Rocketdyne . The program was managed by the Aerospace Systems Directorate within the U.S. Air Force Research Laboratory (AFRL). In the 1990s,

150-547: A pyramid -shaped design with a flat underside and short wings. Heat was conducted through the wings to the upper cool surfaces, where it was dumped into the turbulent air on the top of the wing. In 1960, work on the Blue Streak was canceled as the missile was seen as being obsolete before it could have entered service. Work then moved to the Royal Aircraft Establishment (RAE), where it continued as

225-658: A B-52 was conducted on 9 December 2009, with further flights in early 2010. The first powered flight of the X-51 was planned for 25 May 2010, but the presence of a cargo ship traveling through a portion of the Naval Air Station Point Mugu Sea Range caused a 24-hour delay. The X-51 completed its first powered flight successfully on 26 May 2010. It reached a speed of Mach 5 (3,300 mph; 5,300 km/h), an altitude of 70,000 feet (21,000 m) and flew for over 200 seconds; it did not meet

300-474: A B-52H and was powered to Mach 4.8 (3,200 mph; 5,100 km/h) by the booster rocket. It then separated cleanly from the booster and ignited its own engine. The test aircraft then accelerated to Mach 5.1 (3,400 mph; 5,400 km/h) and flew for 210 seconds until running out of fuel and plunging into the Pacific Ocean off Point Mugu for over six minutes of total flight time; this test

375-613: A faint "sweet and musky " odour when pure. It is the simplest alkene (a hydrocarbon with carbon–carbon double bonds ). Ethylene is widely used in the chemical industry, and its worldwide production (over 150 million tonnes in 2016 ) exceeds that of any other organic compound . Much of this production goes toward creating polythene , which is a widely used plastic containing polymer chains of ethylene units in various chain lengths. Production emits greenhouse gases , including methane from feedstock production and carbon dioxide from any non- sustainable energy used. Ethylene

450-409: A given angle and then developing the body shape that traps that angle, then repeating this process for different angles. For any given speed, a single shape will generate the best results. During re-entry , hypersonic vehicles generate lift only from the underside of the fuselage . The underside, which is inclined to the flow at a high angle of attack , creates lift in reaction to the vehicle wedging

525-409: A lot on the source of energy (for example gas burnt to provide high temperatures ) but that from naptha is certainly more per kg of feedstock. Both steam cracking and production from natural gas via ethane are estimated to emit 1.8 to 2kg of CO2 per kg ethylene produced, totalling over 260 million tonnes a year. This is more than all other manufactured chemicals except cement and ammonia. According to

600-472: A missile similar in size to the X-51. The HSSW was expected to fly in 2020 and enter service in the mid-2020s. It was to have a range of 500–600 nautical miles (930–1,110 km), fly at Mach 5–6, and fit on an F-35 or in the internal bay of a B-2 bomber. Ground tests of the X-51A began in late 2005. A preliminary version of the X-51, the "Ground Demonstrator Engine No. 2", completed wind tunnel tests at

675-549: A multi-speed waverider is a " caret wing ", operated at different angles of attack. A caret wing is a delta wing with longitudinal conical or triangular slots or strakes . It strongly resembles a paper airplane or rogallo wing . The correct angle of attack would become increasingly precise at higher Mach numbers, but this is a control problem that is theoretically solvable. The wing is said to perform even better if it can be constructed of tight mesh, because that reduces its drag, while maintaining lift. Such wings are said to have

750-442: A niche use is as an anesthetic agent (in an 85% ethylene/15% oxygen ratio). Another use is as a welding gas. It is also used as a refrigerant gas for low temperature applications under the name R-1150. Global ethylene production was 107 million tonnes in 2005, 109 million tonnes in 2006, 138 million tonnes in 2010, and 141 million tonnes in 2011. By 2013, ethylene was produced by at least 117 companies in 32 countries. To meet

825-609: A paper on a new 3D underside shape using these techniques. These shapes have superior lifting performance and less drag. Since then, whole families of cone -derived waveriders have been designed using more and more complex conic shocks, based on more complex software. This work eventually led to a conference in 1989, the First International Hypersonic Waverider Conference , held at the University of Maryland. These newest shapes,

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900-536: A precursor to propionic acid and n-propyl alcohol . Ethylene has long represented the major nonfermentative precursor to ethanol . The original method entailed its conversion to diethyl sulfate , followed by hydrolysis. The main method practiced since the mid-1990s is the direct hydration of ethylene catalyzed by solid acid catalysts : Ethylene is dimerized by hydrovinylation to give n -butenes using processes licensed by Lummus or IFP . The Lummus process produces mixed n -butenes (primarily 2-butenes ) while

975-456: A research program into high-speed (Mach 4 to 7) civilian airliners . This work was discovered by engineers at North American Aviation during the early design studies of what would lead to the XB-70 bomber. They re-designed the original "classic" delta wing to incorporate drooping wing tips in order to trap the shock waves mechanically, rather than using a shock cone generated from the front of

1050-589: A top flight speed near Mach 6 (4,000 mph; 6,400 km/h). The X-51 uses JP-7 fuel for the SJY61 scramjet, carrying 270 lb (120 kg) on board. DARPA once viewed X-51 as a stepping stone to Blackswift , a planned hypersonic demonstrator which was canceled in October 2008. In May 2013, the U.S. Air Force planned to apply X-51 technology to the High Speed Strike Weapon (HSSW),

1125-437: A way to control spanwise flow, and thereby increase the amount of air trapped under the wing in the same way as a wing fence . While working on these concepts, he noticed that it was possible to shape the wing in such a way that the shock wave generated off its leading edge would form a horizontal sheet under the craft. In this case, the airflow would not only be trapped horizontally, spanwise, but vertically as well. The only area

1200-478: Is a hypersonic aircraft design that improves its supersonic lift-to-drag ratio by using the shock waves being generated by its own flight as a lifting surface, a phenomenon known as compression lift . The waverider remains a well-studied design for high-speed aircraft in the Mach 5 and higher hypersonic regime, although no such design has yet entered production. The Boeing X-51 scramjet demonstration aircraft

1275-534: Is absorbed by using the JP-7 fuel as a coolant prior to combustion. Other high temperature materials, referred to as SHARP materials (typically zirconium diboride and hafnium diboride ) have been used on steering vanes for ICBM reentry vehicles since the 1970s, and are proposed for use on hypersonic vehicles. They are said to permit Mach 11 flight at 100,000 ft (30,000 m) altitudes and Mach 7 flight at sea level. These materials are more structurally rugged than

1350-416: Is also an important natural plant hormone and is used in agriculture to induce ripening of fruits . The hydrate of ethylene is ethanol . This hydrocarbon has four hydrogen atoms bound to a pair of carbon atoms that are connected by a double bond . All six atoms that comprise ethylene are coplanar . The H-C-H angle is 117.4°, close to the 120° for ideal sp² hybridized carbon. The molecule

1425-480: Is also relatively weak: rotation about the C-C bond is a very low energy process that requires breaking the π-bond by supplying heat at 50 °C. The π-bond in the ethylene molecule is responsible for its useful reactivity. The double bond is a region of high electron density , thus it is susceptible to attack by electrophiles . Many reactions of ethylene are catalyzed by transition metals, which bind transiently to

1500-487: Is no longer available as heat, so this shaping can dramatically reduce the heat load on the spacecraft. Such a design has been the basis for almost every re-entry vehicle since, found on the blunt noses of the early ICBM warheads, the bottoms of the various NASA capsules, and the large nose of the Space Shuttle . The problem with the blunt-nose system is that the resulting design creates very little lift, meaning

1575-401: Is primarily used to make films in packaging , carrier bags and trash liners . Linear alpha-olefins , produced by oligomerization (formation of short-chain molecules) are used as precursors , detergents , plasticisers , synthetic lubricants , additives, and also as co-monomers in the production of polyethylenes. Ethylene is oxidized to produce ethylene oxide , a key raw material in

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1650-412: Is rarely synthesized in the laboratory and is ordinarily purchased. It can be produced via dehydration of ethanol with sulfuric acid or in the gas phase with aluminium oxide or activated alumina . Ethylene is produced from methionine in nature. The immediate precursor is 1-aminocyclopropane-1-carboxylic acid . Ethylene is a fundamental ligand in transition metal alkene complexes . One of

1725-411: Is that it has more area in contact with the shock wave and therefore has more pronounced heat dissipation problems. Waveriders generally have sharp noses and sharp leading edges on their wings. The underside shock-surface remains attached to this. Air flowing in through the shock surface is trapped between the shock and the fuselage, and can only escape at the rear of the fuselage. With sharp edges, all

1800-494: Is the feedstock, ethylene is the product. Ethylene is separated from the resulting mixture by repeated compression and distillation . In Europe and Asia, ethylene is obtained mainly from cracking naphtha, gasoil and condensates with the coproduction of propylene, C4 olefins and aromatics (pyrolysis gasoline). Other technologies employed for the production of ethylene include Fischer-Tropsch synthesis and methanol-to-olefins (MTO). Although of great value industrially, ethylene

1875-463: The Dutch oil , 1,2-dichloroethane ; this discovery gave ethylene the name used for it at that time, olefiant gas (oil-making gas.) The term olefiant gas is in turn the etymological origin of the modern word "olefin", the class of hydrocarbons in which ethylene is the first member. In the mid-19th century, the suffix -ene (an Ancient Greek root added to the end of female names meaning "daughter of")

1950-610: The Reinforced Carbon Composite (RCC) used on the space shuttle nose and leading edges, have higher radiative and temperature tolerance properties, and do not suffer from oxidation issues that RCC needs to be protected against with coatings. A surface material for waverider and hypersonic ( Mach 5 – 10) vehicles developed by scientists at the China Academy of Aerospace Aerodynamics (CAAA) in Beijing

2025-466: The United States and Europe , approximately 90% of ethylene is used to produce ethylene oxide , ethylene dichloride , ethylbenzene and polyethylene . Most of the reactions with ethylene are electrophilic addition . Polyethylene production uses more than half of the world's ethylene supply. Polyethylene, also called polyethene and polythene , is the world's most widely used plastic. It

2100-506: The alkylation with ethylene is ethylbenzene , precursor to styrene . Styrene is used principally in polystyrene for packaging and insulation, as well as in styrene-butadiene rubber for tires and footwear. On a smaller scale, ethyltoluene , ethylanilines, 1,4-hexadiene, and aluminium alkyls. Products of these intermediates include polystyrene , unsaturated polyesters and ethylene-propylene terpolymers . The hydroformylation (oxo reaction) of ethylene results in propionaldehyde ,

2175-407: The fuselage towards the tips. When viewed from the front, the wing resembles a caret symbol ( [REDACTED] ) in cross section , and these designs are often referred to as carets. The more modern 3D version typically looks like a rounded letter 'M'. Theoretically, a star-shaped waverider with a frontal cross-section of a "+" or "×" could reduce drag by another 20%. The disadvantage of this design

2250-465: The "osculating cones waverider", which develops several conical shock waves at different points on the body, blending them to produce a single shaped shock. The expansion to a wider range of compression surface flows allowed the design of waveriders with control of volume, upper surface shape, engine integration and centre of pressure position. Performance improvements and off-design analysis continued until 1970. During this period at least one waverider

2325-402: The "viscous optimized waveriders", look similar to conical designs as long as the angle of the shock wave on the nose is beyond some critical angle, about 14 degrees for a Mach 6 design for instance. The angle of the shock can be controlled by widening out the nose into a curved plate of specific radius, and reducing the radius produces a smaller shock cone angle. Vehicle design starts by selecting

Boeing X-51 Waverider - Misplaced Pages Continue

2400-540: The 1950s, the British started a space program based around the Blue Streak missile , which was, at some point, to include a crewed vehicle. Armstrong-Whitworth were contracted to develop the re-entry vehicle, and unlike the U.S. space program, they decided to stick with a winged vehicle instead of a ballistic capsule . Between 1957 and 1959, they contracted Nonweiler to develop his concepts further. This work produced

2475-764: The Air Force Research Laboratory (AFRL) began the HyTECH program for hypersonic propulsion . Pratt & Whitney received a contract from the AFRL to develop a hydrocarbon-fueled scramjet engine which led to the development of the SJX61 engine. The SJX61 engine was originally meant for the NASA X-43C , which was eventually canceled. The engine was applied to the AFRL's Scramjet Engine Demonstrator program in late 2003. The scramjet flight test vehicle

2550-510: The IFP process produces 1-butene . 1-Butene is used as a comonomer in the production of certain kinds of polyethylene . Ethylene is a hormone that affects the ripening and flowering of many plants. It is widely used to control freshness in horticulture and fruits . The scrubbing of naturally occurring ethylene delays ripening. Adsorption of ethylene by nets coated in titanium dioxide gel has also been shown to be effective. An example of

2625-493: The NASA Langley Research Center on 27 July 2006. Testing continued there until a simulated X-51 flight at Mach 5 was successfully completed on 30 April 2007. The testing is intended to observe acceleration between Mach 4 and Mach 6 and to demonstrate that hypersonic thrust "isn't just luck". Four captive test flights were initially planned for 2009. However, the first captive flight of the X-51A on

2700-410: The air above the shock wave could escape would be out the back of the sheet where the fuselage ended. Since the air was trapped between this sheet and the fuselage, a large volume of air would be trapped, much more than the more basic approach he first developed. Furthermore, since the shock surface was held at a distance from the craft, shock heating was limited to the leading edges of the wings, lowering

2775-407: The aircraft. This mechanism also had two other beneficial effects; it reduced the amount of horizontal lifting surface at the rear of the aircraft, which helped offset a nose-down trim that occurs at high speeds, and it added more vertical surface which helped improve the directional stability, which decreased at high speed. Nonweiler's original design used the shock wave generated by the aircraft as

2850-502: The airflow downwards. The amount of lift is not particularly high, compared to a traditional wing , but more than enough to maneuver given the amount of distance the vehicle covers. Most re-entry vehicles have been based on the blunt-nose reentry design pioneered by Theodore von Kármán . He demonstrated that a shock wave is forced to "detach" from a curved surface, forced out into a larger configuration that requires considerable energy to form. Energy expended in forming this shock wave

2925-410: The bottom (extremely long gliding profiles at high altitude), and the Space Shuttle somewhere in the middle. Simple waveriders have substantial design problems. First, the obvious designs only work at a particular Mach number , and the amount of lift captured will change dramatically as the vehicle changes speed. Another problem is that the waverider depends on radiative cooling , possible as long as

3000-490: The boundary layer starts to interact with the air trapped between the shock wave and the fuselage, the air that is being used for lift on a waverider. Calculating the effects of these interactions was beyond the abilities of aerodynamics until the introduction of useful computational fluid dynamics starting in the 1980s. In 1981, Maurice Rasmussen at the University of Oklahoma started a waverider renaissance by publishing

3075-422: The caret wing waverider in the later 1960s as a part of a three-stage lunar rocket design. The first stage was built on an expanded Blue Steel , the second a waverider, and the third a nuclear-powered crewed stage. This work was generalized in 1971 to produce a two-staged reusable spacecraft. The 121-foot (37 m) long first stage was designed as a classical waverider, with air-breathing propulsion for return to

Boeing X-51 Waverider - Misplaced Pages Continue

3150-486: The center and the two sides folded downward. From the rear it looks like an upside-down V, or alternately, the " caret ", ^, and such designs are known as "caret wings". Two to three years later the concept briefly came into the public eye, due to the airliner work at the RAE that led to the prospect of reaching Australia in 90 minutes. Newspaper articles led to an appearance on Scottish Television . Hawker Siddeley examined

3225-521: The craft lost control and crashed into the Pacific. The Air Force Research Laboratory (AFRL) determined the problem was the X-51's upper right aerodynamic fin unlocked during flight and became uncontrollable; all four fins are needed for aerodynamic control. The aircraft lost control before the scramjet engine could ignite. On 1 May 2013, the X-51 performed its first fully successful flight test on its fourth test flight. The X-51 and booster detached from

3300-416: The ethylene using both the π and π* orbitals. Being a simple molecule, ethylene is spectroscopically simple. Its UV-vis spectrum is still used as a test of theoretical methods. Major industrial reactions of ethylene include in order of scale: 1) polymerization , 2) oxidation , 3) halogenation and hydrohalogenation , 4) alkylation , 5) hydration , 6) oligomerization , and 7) hydroformylation . In

3375-613: The ever-increasing demand for ethylene, sharp increases in production facilities are added globally, particularly in the Mideast and in China . Production emits greenhouse gas , namely significant amounts of carbon dioxide. Ethylene is produced by several methods in the petrochemical industry . A primary method is steam cracking (SC) where hydrocarbons and steam are heated to 750–950 °C. This process converts large hydrocarbons into smaller ones and introduces unsaturation. When ethane

3450-680: The first organometallic compounds, Zeise's salt is a complex of ethylene. Useful reagents containing ethylene include Pt(PPh 3 ) 2 (C 2 H 4 ) and Rh 2 Cl 2 (C 2 H 4 ) 4 . The Rh-catalysed hydroformylation of ethylene is conducted on an industrial scale to provide propionaldehyde . Some geologists and scholars believe that the famous Greek Oracle at Delphi (the Pythia ) went into her trance-like state as an effect of ethylene rising from ground faults. Ethylene appears to have been discovered by Johann Joachim Becher , who obtained it by heating ethanol with sulfuric acid; he mentioned

3525-817: The gas in his Physica Subterranea (1669). Joseph Priestley also mentions the gas in his Experiments and observations relating to the various branches of natural philosophy: with a continuation of the observations on air (1779), where he reports that Jan Ingenhousz saw ethylene synthesized in the same way by a Mr. Enée in Amsterdam in 1777 and that Ingenhousz subsequently produced the gas himself. The properties of ethylene were studied in 1795 by four Dutch chemists, Johann Rudolph Deimann, Adrien Paets van Troostwyck, Anthoni Lauwerenburgh and Nicolas Bondt, who found that it differed from hydrogen gas and that it contained both carbon and hydrogen. This group also discovered that ethylene could be combined with chlorine to produce

3600-490: The heat of re-entry. At the time, Nonweiler was forced to use a greatly simplified 2D model of airflow around the aircraft, which he realized would not be accurate due to spanwise flow across the wing. However, he also noticed that the spanwise flow would be stopped by the shockwave being generated by the aircraft, and that if the wing was positioned to deliberately approach the shock, the spanwise flow would be trapped under wing, increasing pressure, and thus increasing lift. In

3675-531: The initial complexation of ethylene to a Pd(II) center. Major intermediates from the halogenation and hydrohalogenation of ethylene include ethylene dichloride , ethyl chloride , and ethylene dibromide . The addition of chlorine entails " oxychlorination ", i.e. chlorine itself is not used. Some products derived from this group are polyvinyl chloride , trichloroethylene , perchloroethylene , methyl chloroform , polyvinylidene chloride and copolymers , and ethyl bromide . Major chemical intermediates from

3750-430: The launch site. The upper stage was designed as a lifting body, and would have carried an 8000-pound (3.6 t) payload to low Earth orbit . Nonweiler's work was based on studies of planar 2D shocks due to the difficulty understanding and predicting real-world shock patterns around 3D bodies. As the study of hypersonic flows improved, researchers were able to study waverider designs that used different shockwave shapes,

3825-408: The lift is retained. Even though sharp edges get much hotter than rounded ones at the same air density, the improved lift means that waveriders can glide on re-entry at much higher altitudes where the air density is lower. A list ranking various space vehicles in order of heating applied to the airframe would have capsules at the top (re-entering quickly with very high heating loads), waveriders at

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3900-459: The name ethylene was deeply entrenched, and it remains in wide use today, especially in the chemical industry. Following experimentation by Luckhardt, Crocker, and Carter at the University of Chicago, ethylene was used as an anesthetic. It remained in use through the 1940s use even while chloroform was being phased out. Its pungent odor and its explosive nature limit its use today. The 1979 IUPAC nomenclature rules made an exception for retaining

3975-451: The non-systematic name ethylene ; however, this decision was reversed in the 1993 rules, and it remains unchanged in the newest 2013 recommendations, so the IUPAC name is now ethene . In the IUPAC system, the name ethylene is reserved for the divalent group -CH 2 CH 2 -. Hence, names like ethylene oxide and ethylene dibromide are permitted, but the use of the name ethylene for

4050-441: The planned 300 second flight duration, however. The test had the longest hypersonic flight time of 140 seconds while under its scramjet power. The X-43 had the previous longest flight burn time of 12 seconds, while setting a new speed record of Mach 9.68. Three more test flights were planned and used the same flight trajectory . Boeing proposed to the Air Force Research Laboratory (AFRL) that two test flights be added to increase

4125-444: The production of surfactants and detergents by ethoxylation . Ethylene oxide is also hydrolyzed to produce ethylene glycol , widely used as an automotive antifreeze as well as higher molecular weight glycols, glycol ethers , and polyethylene terephthalate . Ethylene oxidation in the presence of a palladium catalyst can form acetaldehyde . This conversion remains a major industrial process (10M kg/y). The process proceeds via

4200-431: The shock waves generated from the nose of the aircraft. Normally the boundary layer is quite thin compared to the streamline of airflow over the wing, and can be considered separately from other aerodynamic effects. However, as the speed increases and the shock wave increasingly approaches the sides of the craft, there comes a point where the two start to interact and the flowfield becomes very complex. Long before that point,

4275-411: The shock. Like the caret wing, they have to be designed to operate at a specific speed to properly attach the shock wave to the wing's leading edge, but unlike them the entire body shape can be varied dramatically at the different design speeds, and sometimes have wingtips that curve upward to attach to the shockwave. Further development of the conical sections, adding canopies and fuselage areas, led to

4350-403: The simplest being the conical shock generated by a cone. In these cases, a waverider is designed to keep the rounded shockwave attached to its wings, not a flat sheet, which increases the volume of air trapped under the surface, and thereby increases lift. Unlike the caret wing, the cone flow designs smoothly curve their wings, from near horizontal in the center, to highly drooped where they meet

4425-582: The suffixes -ane, -ene, -ine, -one, and -une were used to denote the hydrocarbons with 0, 2, 4, 6, and 8 fewer hydrogens than their parent alkane . In this system, ethylene became ethene . Hofmann's system eventually became the basis for the Geneva nomenclature approved by the International Congress of Chemists in 1892, which remains at the core of the IUPAC nomenclature. However, by that time,

4500-442: The test was being investigated. A B-52 released the X-51 at an approximate altitude of 50,000 feet (15,000 m). The X-51's scramjet engine lit on ethylene , but did not properly transition to JP-7 fuel operation. The third test flight took place on 14 August 2012. The X-51 was to make a 300-second (5 minutes) experimental flight at speeds of Mach 5 (3,300 mph; 5,300 km/h). After separating from its rocket booster,

4575-546: The thermal loads on the fuselage. In 1962 Nonweiler moved to Glasgow University to become Professor of Aerodynamics and Fluid Mechanics. That year his "Delta Wings of Shapes Amenable to Exact Shock-Wave Theory" was published by the Journal of the Royal Aeronautical Society , and earned him that society's Gold Medal . A craft generated using this model looks like a delta wing that has been broken down

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4650-419: The total to six, with flights taking place at four to six week intervals, provided there are no failures. The second test flight was initially scheduled for 24 March 2011, but was not conducted due to unfavorable test conditions. The flight took place on 13 June 2011. However, the flight over the Pacific Ocean ended early due to an inlet unstart event after being boosted to Mach 5 speed. The flight data from

4725-532: The two-carbon alkene is not. Nevertheless, use of the name ethylene for H 2 C=CH 2 (and propylene for H 2 C=CHCH 3 ) is still prevalent among chemists in North America. "A key factor affecting petrochemicals life-cycle emissions is the methane intensity of feedstocks, especially in the production segment." Emissions from cracking of naptha and natural gas (common in the US as gas is cheap there) depend

4800-553: The unusual attribute of operating at a wide range of Mach numbers in different fluids with a wide range of Reynolds numbers . The temperature problem can be solved with some combination of a transpiring surface, exotic materials, and possibly heat-pipes . In a transpiring surface, small amounts of a coolant such as water are pumped through small holes in the aircraft's skin (see transpiration and perspiration ). This design works for Mach 25 spacecraft re-entry shields , and therefore should work for any aircraft that can carry

4875-401: The upper part of the wing through the gap between the leading edge and the detached shock wave. This loss of airflow reduced (by up to a quarter) the lift being generated by the waverider, which led to studies on how to avoid this problem and keep the flow trapped under the wing. Nonweiler's resulting design is a delta-wing with some amount of negative dihedral — the wings are bent down from

4950-526: The vehicle has problems maneuvering during re-entry. If the spacecraft is meant to be able to return to its point of launch "on command", then some sort of maneuvering will be required to counteract the fact that the Earth is turning under the spacecraft as it flies. After a single low Earth orbit , the launching point will be over 1,000 km (600 mi) to the east of the spacecraft by the time it has completed one full orbit. A considerable amount of research

5025-561: The vehicle spends most of its time at very high altitudes. However these altitudes also demand a very large wing to generate the needed lift in the thin air, and that same wing can become rather unwieldy at lower altitudes and speeds. Because of these problems, waveriders have not found favor with practical aerodynamic designers, despite the fact that they might make long-distance hypersonic vehicles efficient enough to carry air freight . Some researchers controversially claim that there are designs that overcome these problems. One candidate for

5100-491: The weight of the coolant. Exotic materials such as carbon-carbon composite do not conduct heat but endure it, but they tend to be brittle . Heatpipes are not widely used at present. Like a conventional heat exchanger , they conduct heat better than most solid materials, but like a thermosiphon are passively pumped. The Boeing X-51A deals with external heating through the use of a tungsten nosecone and space shuttle-style heat shield tiles on its belly. Internal (engine) heating

5175-488: Was dedicated to combining the blunt-nose system with wings, leading to the development of the lifting body designs in the U.S. It was while working on one such design that Nonweiler developed the waverider. He noticed that the detachment of the shock wave over the blunt leading edges of the wings of the Armstrong-Whitworth design would allow the air on the bottom of the craft to flow spanwise and escape to

5250-461: Was designated X-51 on 27 September 2005. In flight demonstrations, the X-51 is carried by a B-52 to an altitude of about 50,000 feet (15 km; 9.5 mi) and then released over the Pacific Ocean. The X-51 is initially propelled by an MGM-140 ATACMS solid rocket booster to approximately Mach 4.5 (3,000 mph; 4,800 km/h). The booster is then jettisoned and the vehicle's Pratt & Whitney Rocketdyne SJY61 scramjet accelerates it to

5325-486: Was tested at the Woomera Rocket Range , mounted on the nose of an air-launched Blue Steel missile , and a number of airframes were tested in the wind tunnel at NASA's Ames Research Center . However, during the 1970s most work in hypersonics disappeared, and the waverider along with it. One of the many differences between supersonic and hypersonic flight concerns the interaction of the boundary layer and

5400-479: Was tested during 2023. An alternative developed by RTX Corporation uses a perspiring membrane developed under work supported by the United States Air Force under Contract No. United States Air Force FA8650-20-C-7001 Ethylene Ethylene ( IUPAC name: ethene ) is a hydrocarbon which has the formula C 2 H 4 or H 2 C=CH 2 . It is a colourless, flammable gas with

5475-467: Was tested from 2010 to 2013. In its final test flight, it reached a speed of Mach 5.1 (5,400 km/h; 3,400 mph). The waverider design concept was first developed by Terence Nonweiler of the Queen's University of Belfast , and first described in print in 1951 as a re-entry vehicle. It consisted of a delta-wing platform with a low wing loading to provide considerable surface area to dump

5550-491: Was the longest air-breathing hypersonic flight. Researchers collected telemetry data for 370 seconds of flight. The test signified the completion of the program. The Air Force Research Laboratory believes the successful flight will serve as research for practical applications of hypersonic flight, such as a missile, reconnaissance, transport, and air-breathing first stage for a space system. Data from Boeing, Air Force Performance Waverider A waverider

5625-454: Was widely used to refer to a molecule or part thereof that contained one fewer hydrogen atoms than the molecule being modified. Thus, ethylene ( C 2 H 4 ) was the "daughter of ethyl " ( C 2 H 5 ). The name ethylene was used in this sense as early as 1852. In 1866, the German chemist August Wilhelm von Hofmann proposed a system of hydrocarbon nomenclature in which

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