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40-653: By 2018, Russia had revived the 600-metric-ton- maximum-takeoff-weight (1,300,000 lb; 600,000 kg) project, with plans to use it for search and rescue operations in the Arctic and Pacific, as well as cargo and troop delivery (up to 550 troops) to remote military bases. A military advantage of ground-effect vehicles over ships and submarines was that they did not have draft during operation, and therefore could not be detected by sonar and could not be hit by torpedoes. Advantages over aircraft include operation at low altitude , which makes radar acquisition difficult, and

80-444: A "CO/ALR" coding. Another way to forestall the heating problem is to crimp the short " pigtail " of copper wire. A properly done high-pressure crimp by the proper tool is tight enough to reduce any thermal expansion of the aluminium. Today, new alloys, designs, and methods are used for aluminium wiring in combination with aluminium terminations. Wrought and cast aluminium alloys use different identification systems. Wrought aluminium

120-563: A larger payload . This was particularly interesting during the Cold War as a way to inconspicuously and quickly transport many people or large cargo over long distances. The Spasatel was originally built as a second Lun -class anti-ship missile-carrying ekranoplan. After the Soviet nuclear submarine K-278 Komsomolets sank in 1989, killing 42 people, the Spasatel was repurposed to be deployed in

160-551: A number system ( ANSI ) or by names indicating their main alloying constituents ( DIN and ISO ). Selecting the right alloy for a given application entails considerations of its tensile strength , density , ductility , formability, workability, weldability , and corrosion resistance, to name a few. A brief historical overview of alloys and manufacturing technologies is given in Ref. Aluminium alloys are used extensively in aircraft due to their high strength-to-weight ratio . Pure aluminium

200-420: A one to three digit number, e.g. 6061-T6. The definitions for the tempers are: -F  : As fabricated -H  : Strain hardened (cold worked) with or without thermal treatment -O  : Full soft (annealed) -T  : Heat treated to produce stable tempers -W  : Solution heat treated only Note: -W is a relatively soft intermediary designation that applies after heat treat and before aging

240-415: A regeneratively cooled aluminium design for some parts of the nozzle, including the thermally critical throat region; in fact the extremely high thermal conductivity of aluminium prevented the throat from reaching the melting point even under massive heat flux, resulting in a reliable, lightweight component. Because of its high conductivity and relatively low price compared with copper in the 1960s, aluminium

280-470: A steel part of identical size and shape. With completely new metal products, the design choices are often governed by the choice of manufacturing technology. Extrusions are particularly important in this regard, owing to the ease with which aluminium alloys, particularly the Al-Mg-Si series, can be extruded to form complex profiles. In general, stiffer and lighter designs can be achieved with aluminium alloy than

320-452: A wet environment, galvanic corrosion can occur when an aluminium alloy is placed in electrical contact with other metals with more positive corrosion potentials than aluminium, and an electrolyte is present that allows ion exchange. Also referred to as dissimilar-metal corrosion, this process can occur as exfoliation or as intergranular corrosion. Aluminium alloys can be improperly heat treated, causing internal element separation which corrodes

360-468: Is a major concern. Such crossover aluminium alloys can be hardened via precipitation of a chemical complex phase known as T-phase in which the radiation resistance has been proved to be superior than other hardening phases of conventional aluminium alloys. The following aluminium alloys are commonly used in aircraft and other aerospace structures: Note that the term aircraft aluminium or aerospace aluminium usually refers to 7075. 4047 aluminium

400-407: Is a unique alloy used in both the aerospace and automotive applications as a cladding alloy or filler material. As filler, aluminium alloy 4047 strips can be combined to intricate applications to bond two metals. 6951 is a heat treatable alloy providing additional strength to the fins while increasing sag resistance; this allows the manufacturer to reduce the gauge of the sheet and therefore reducing

440-407: Is completed. The -W condition can be extended at extremely low temperatures but not indefinitely and depending on the material will typically last no longer than 15 minutes at ambient temperatures. The International Alloy Designation System is the most widely accepted naming scheme for wrought alloys. Each alloy is given a four-digit number, where the first digit indicates the major alloying elements,

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480-756: Is considered a permanent modification. Alternatively, holders of an Air Operator Certificate (AOC) may vary the Maximum Declared Take-Off Weight (MDTOW) for their aircraft. They can subscribe to a scheme, and then vary the weight for each aircraft without further charge. An aircraft can have its MTOW increased by reinforcement due to additional or stronger materials. For example, the Airbus A330 242 tonnes MTOW variant / A330neo uses Scandium–aluminium (scalmalloy) to avoid an empty weight increase. In many circumstances an aircraft may not be permitted to take off at its MTOW. In these circumstances

520-522: Is feasible with steels. For instance, consider the bending of a thin-walled tube: the second moment of area is inversely related to the stress in the tube wall, i.e. stresses are lower for larger values. The second moment of area is proportional to the cube of the radius times the wall thickness, thus increasing the radius (and weight) by 26% will lead to a halving of the wall stress. For this reason, bicycle frames made of aluminium alloys make use of larger tube diameters than steel or titanium in order to yield

560-414: Is identified with a four digit number which identifies the alloying elements. Cast aluminium alloys use a four to five digit number with a decimal point. The digit in the hundreds place indicates the alloying elements, while the digit after the decimal point indicates the form (cast shape or ingot). The temper designation follows the cast or wrought designation number with a dash, a letter, and potentially

600-813: Is in aluminium–scandium alloys for minor aerospace industry components. These alloys contain between 0.1% and 0.5% (by weight) of scandium. They were used in the Russian military aircraft MiG-21 and MiG-29 . Some items of sports equipment, which rely on high performance materials, have been made with scandium–aluminium alloys, including baseball bats , lacrosse sticks, as well as bicycle frames and components, and tent poles. U.S. gunmaker Smith & Wesson produces revolvers with frames composed of scandium alloy and cylinders of titanium. Due to its light-weight and high strength, aluminium alloys are desired materials to be applied in spacecraft, satellites and other components to be deployed in space. However, this application

640-475: Is limited by the energetic particle irradiation emitted by the Sun . The impact and deposition of solar energetic particles within the microstructure of conventional aluminium alloys can induce the dissolution of most common hardening phases, leading to softening. The recently introduced crossover aluminium alloys are being tested as a surrogate to 6xxx and 7xxx series in environments where energetic particle irradiation

680-419: Is much too soft for such uses, and it does not have the high tensile strength that is needed for building airplanes and helicopters . Aluminium alloys typically have an elastic modulus of about 70 GPa , which is about one-third of the elastic modulus of steel alloys . Therefore, for a given load, a component or unit made of an aluminium alloy will experience a greater deformation in the elastic regime than

720-562: Is not seen in current aluminium cylinder heads. An important structural limitation of aluminium alloys is their lower fatigue strength compared to steel. In controlled laboratory conditions, steels display a fatigue limit , which is the stress amplitude below which no failures occur – the metal does not continue to weaken with extended stress cycles. Aluminium alloys do not have this lower fatigue limit and will continue to weaken with continued stress cycles. Aluminium alloys are therefore sparsely used in parts that require high fatigue strength in

760-481: Is required. Alloys composed mostly of aluminium have been very important in aerospace manufacturing since the introduction of metal-skinned aircraft. Aluminium–magnesium alloys are both lighter than other aluminium alloys and much less flammable than other alloys that contain a very high percentage of magnesium. Aluminium alloy surfaces will develop a white, protective layer of aluminium oxide if left unprotected by anodizing and/or correct painting procedures. In

800-463: Is the lowest of the: Aluminium alloy#Aluminium–scandium An aluminium alloy ( UK / IUPAC ) or aluminum alloy ( NA ; see spelling differences ) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper , magnesium , manganese , silicon , tin , nickel and zinc . There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into

840-595: The maritime search and rescue mission, and seating for up to 500 passengers was planned. After the disintegration of the Soviet Union , the project was cancelled for financial reasons. Military operations at sea were also greatly reduced, so the intended use became less important. The unfinished Spasatel is stored in an old industrial complex in Nizhny Novgorod as of 2020. According to press reports in December 2017,

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880-461: The maximum structural takeoff weight or maximum structural takeoff mass , is the maximum weight at which the pilot is allowed to attempt to take off , due to structural or other limits. The analogous term for rockets is gross lift-off mass , or GLOW . MTOW is usually specified in units of kilograms or pounds. MTOW is the heaviest weight at which the aircraft has been shown to meet all the airworthiness requirements applicable to it. It refers to

920-401: The aircraft structure is capable of withstanding all the loads likely to be imposed on it during the takeoff, and occasionally by the maximum flight weight . It is possible to have an aircraft certified with a reduced MTOW, lower than the structural maximum, to take advantage of lower MTOW-based fees, such as insurance premiums, landing fees and air traffic control fees are MTOW based. This

960-582: The categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions . Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si , where the high levels of silicon (4–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance

1000-436: The desired stiffness and strength. In automotive engineering, cars made of aluminium alloys employ space frames made of extruded profiles to ensure rigidity. This represents a radical change from the common approach for current steel car design, which depend on the body shells for stiffness, known as unibody design. Aluminium alloys are widely used in automotive engines, particularly in engine blocks and crankcases due to

1040-441: The development of the Spasatel might be resumed, for use mainly in Arctic waters, with production beginning as early as 2025. According to Russian media, as of November 2017, the project was included in the arms budget for the years 2018 to 2025. Maximum takeoff weight The maximum takeoff weight ( MTOW ) or maximum gross takeoff weight ( MGTOW ) or maximum takeoff mass ( MTOM ) of an aircraft , also known as

1080-401: The high cycle regime (more than 10 stress cycles). Often, the metal's sensitivity to heat must also be considered. Even a relatively routine workshop procedure involving heating is complicated by the fact that aluminium, unlike steel, will melt without first glowing red. Forming operations where a blow torch is used can reverse or remove the effects of heat treatment. No visual signs reveal how

1120-452: The highest strength of non-heat-treated alloys. Most 5000 series alloys include manganese as well. 6000 series are alloyed with magnesium and silicon. They are easy to machine, are weldable , and can be precipitation hardened, but not to the high strengths that 2000 and 7000 can reach. 6061 alloy is one of the most commonly used general-purpose aluminium alloys. 7000 series are alloyed with zinc, and can be precipitation hardened to

1160-454: The highest strengths of any aluminium alloy. Most 7000 series alloys include magnesium and copper as well. 8000 series are alloyed with other elements which are not covered by other series. Aluminium–lithium alloys are an example. The Aluminum Association (AA) has adopted a nomenclature similar to that of wrought alloys. British Standard and DIN have different designations. In the AA system,

1200-596: The material is internally damaged. Much like welding heat treated, high strength link chain, all strength is now lost by heat of the torch. The chain is dangerous and must be discarded. Aluminium is subject to internal stresses and strains. Sometimes years later, improperly welded aluminium bicycle frames may gradually twist out of alignment from the stresses of the welding process. Thus, the aerospace industry avoids heat altogether by joining parts with rivets of like metal composition, other fasteners, or adhesives. Stresses in overheated aluminium can be relieved by heat-treating

1240-418: The maximum permissible aircraft weight at the start of the takeoff run. MTOW of an aircraft is fixed and does not vary with altitude, air temperature, or the length of the runway to be used for takeoff or landing. Maximum permissible takeoff weight or "regulated takeoff weight", varies according to flap setting, altitude, air temperature, length of runway and other factors. It is different from one takeoff to

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1280-437: The maximum weight permitted for takeoff will be determined taking account of the following: The maximum weight at which a takeoff may be attempted, taking into account the above factors, is called the maximum permissible takeoff weight, maximum allowed takeoff weight or regulated takeoff weight. The Field Limited Weight is the lowest of the: The Runway Limited Weight is the lowest of the: The Regulated Take-Off Weight

1320-512: The metal from the inside out. Aluminium alloy compositions are registered with The Aluminum Association . Many organizations publish more specific standards for the manufacture of aluminium alloy, including the SAE International standards organization, specifically its aerospace standards subgroups, and ASTM International . Aluminium alloys with a wide range of properties are used in engineering structures. Alloy systems are classified by

1360-542: The most common aerospace alloys, but were susceptible to stress corrosion cracking and are increasingly replaced by 7000 series in new designs. 3000 series are alloyed with manganese , and can be work hardened . 4000 series are alloyed with silicon. Variations of aluminium–silicon alloys intended for casting (and therefore not included in 4000 series) are also known as silumin . 5000 series are alloyed with magnesium, and offer superb corrosion resistance, making them suitable for marine applications. 5083 alloy has

1400-479: The next, but can never be higher than the MTOW. Certification standards applicable to the airworthiness of an aircraft contain many requirements. Some of these requirements can only be met by specifying a maximum weight for the aircraft, and demonstrating that the aircraft can meet the requirement at all weights up to, and including, the specified maximum. This limit is typically driven by structural requirements – to ensure

1440-639: The parts in an oven and gradually cooling it—in effect annealing the stresses. Yet these parts may still become distorted, so that heat-treating of welded bicycle frames, for instance, can result in a significant fraction becoming misaligned. If the misalignment is not too severe, the cooled parts may be bent into alignment. If the frame is properly designed for rigidity (see above), that bending will require enormous force. Aluminium's intolerance to high temperatures has not precluded its use in rocketry; even for use in constructing combustion chambers where gases can reach 3500 K. The RM-81 Agena upper stage engine used

1480-442: The second two digits reveal the minimum percentage of aluminium, e.g. 150.x correspond to a minimum of 99.50% aluminium. The digit after the decimal point takes a value of 0 or 1, denoting casting and ingot respectively. The main alloying elements in the AA system are as follows: Titanium alloys , which are stronger but heavier than Al-Sc alloys, are still much more widely used. The main application of metallic scandium by weight

1520-668: The second — if different from 0 — indicates a variation of the alloy, and the third and fourth digits identify the specific alloy in the series. For example, in alloy 3105, the number 3 indicates the alloy is in the manganese series, 1 indicates the first modification of alloy 3005, and finally 05 identifies it in the 3000 series. 1000 series are essentially pure aluminium with a minimum 99% aluminium content by weight and can be work hardened . Not an International Alloy Designation System name 2000 series are alloyed with copper, can be precipitation hardened to strengths comparable to steel. Formerly referred to as duralumin , they were once

1560-496: The weight savings that are possible. Since aluminium alloys are susceptible to warping at elevated temperatures, the cooling system of such engines is critical. Manufacturing techniques and metallurgical advancements have also been instrumental for the successful application in automotive engines. In the 1960s, the aluminium cylinder heads of the Chevrolet Corvair earned a reputation for failure and stripping of threads , which

1600-635: Was introduced at that time for household electrical wiring in North America, even though many fixtures had not been designed to accept aluminium wire. But the new use brought some problems: All of this resulted in overheated and loose connections, and this in turn resulted in some fires. Builders then became wary of using the wire, and many jurisdictions outlawed its use in very small sizes, in new construction. Yet newer fixtures eventually were introduced with connections designed to avoid loosening and overheating. At first they were marked "Al/Cu", but they now bear

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