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73-607: The M829 is an American armor-piercing fin-stabilized discarding sabot ( APFSDS ) kinetic energy penetrator tank round . Modeling was done at the Ballistic Research Laboratory at Aberdeen Proving Ground , which was incorporated into the Army Research Laboratory in 1992. The round is specifically designed for the 120 mm M256 main gun on the Abrams M1A1 and M1A2 main battle tanks . The penetrator

146-416: A nozzle , thereby producing thrust. In rockets, the burning of rocket fuel produces an exhaust, and the exhausted material is usually expelled as a propellant under pressure through a nozzle . The exhaust material may be a gas , liquid , plasma , or a solid . In powered aircraft without propellers such as jets , the propellant is usually the product of the burning of fuel with atmospheric oxygen so that

219-416: A nozzle , thereby producing thrust. In rockets, the burning of rocket fuel produces an exhaust, and the exhausted material is usually expelled as a propellant under pressure through a nozzle . The exhaust material may be a gas , liquid , plasma , or a solid . In powered aircraft without propellers such as jets , the propellant is usually the product of the burning of fuel with atmospheric oxygen so that

292-460: A plasma which is used as the propellant. They use a nozzle to direct the energized propellant. The nozzle itself may be composed simply of a magnetic field. Low molecular weight gases (e.g. hydrogen, helium, ammonia) are preferred propellants for this kind of system. Electromagnetic thrusters use ions as the propellant, which are accelerated by the Lorentz force or by magnetic fields, either of which

365-439: A reaction engine . Although technically a propellant is the reaction mass used to create thrust, the term "propellant" is often used to describe a substance which contains both the reaction mass and the fuel that holds the energy used to accelerate the reaction mass. For example, the term "propellant" is often used in chemical rocket design to describe a combined fuel/propellant, although the propellants should not be confused with

438-656: A $ 77 million, three-year contract on 11 July 2011 to develop and qualify the M829A4 Advanced Kinetic Energy (AKE) round for the U.S. Army's M1A2 SEP (System Enhancement Package) Abrams MBT. The M829A4 is a fifth-generation APFSDS-T cartridge using a depleted-uranium penetrator with a three-petal composite sabot; the penetrator includes a low-drag fin with a tracer and a windshield and tip assembly. Its propellant maintains consistent muzzle velocities across operational temperatures from −25 to 145 °F (−32 to 63 °C). The new Advanced Combustible Cartridge Case

511-497: A 627 mm (24.7 in) DU penetrator with a 27 mm (1.1 in) rod diameter, which reaches a muzzle velocity of 1,670 meters per second (5,500 ft/s) using 8.1 kg (18 lb) of JA-2 propellant. Its maximum effective range is 3,000 m (3,300 yd). According to Jane's , the M829 is capable of penetrating 540 mm (21 in) of RHA steel armor at up to a 2,000 m (2,200 yd) range. The original M829

584-655: A US$ 12 million contract to defense contractor General Dynamics for the demilitarization and disposal of 78,000 aging depleted-uranium (DU) tank rounds as newer rounds are added to the U.S. war reserves. The contract includes M829A1 and M829A2 rounds. With the Soviet creation of the Kontakt-5 Explosive Reactive Armor ( ERA ), the M829A2 was the US immediate response, developed in part to take on this new ERA type. The M829A3

657-483: A broad variety of payloads. Aerosol sprays , in which a liquid is ejected as a spray, include paints, lubricants, degreasers, and protective coatings; deodorants and other personal care products; cooking oils. Some liquid payloads are not sprayed due to lower propellant pressure and/or viscous payload, as with whipped cream and shaving cream or shaving gel. Low-power guns, such as BB guns , paintball guns, and airsoft guns, have solid projectile payloads. Uniquely, in

730-409: A bullet requires at least 1 turn in 7 inch twist, (1:7 rifling), in 5.56mm, it will also require at least 1:7 rifling when saboted in 7.62mm. However, larger caliber commercial rifles generally don't need such fast twist rates; 1:10 being a readily available standard in 7.62mm. As a result, the twist rate of the larger barrel will dictate which smaller bullets can be fired with sufficient stability out of

803-441: A chamber pressure of 5,600 bars (81,221 psi), which results in a muzzle velocity of 1,575 m/s (5,170 ft/s). The 684-millimeter-long (26.9 in) penetrator and its sabot together weigh 9 kg (20 lb). The mass of the penetrator alone is 4.6 kg (10 lb). The effective target range is 3,000 m (3,300 yd). The next generation ammunition, called 120 mm APFSDS-T M829A2, entered service in 1994 and

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876-400: A compressor, rather than by a chemical reaction. The pressures and energy densities that can be achieved, while insufficient for high-performance rocketry and firearms, are adequate for most applications, in which case compressed fluids offer a simpler, safer, and more practical source of propellant pressure. A compressed fluid propellant may simply be a pressurized gas, or a substance which is

949-399: A fluid which is used to expel the products of that chemical reaction (and sometimes other substances) as propellants. For example, in a simple hydrogen/oxygen engine, hydrogen is burned (oxidized) to create H 2 O and the energy from the chemical reaction is used to expel the water (steam) to provide thrust. Often in chemical rocket engines, a higher molecular mass substance is included in

1022-414: A form of spindle sabot. Shotgun slugs often use a cast plastic sabot similar to the spindle sabot. Shotgun sabots in general extend the full length of the projectile and are designed to be used more effectively in rifled barrels. A ring sabot uses the rear fins on a long rod projectile to help center the projectile and ride the bore, and the multi-petal sabot forms only a single bulkhead ring around

1095-431: A gas at atmospheric pressure, but stored under pressure as a liquid. In applications in which a large quantity of propellant is used, such as pressure washing and airbrushing , air may be pressurized by a compressor and used immediately. Additionally, a hand pump to compress air can be used for its simplicity in low-tech applications such as atomizers , plant misters and water rockets . The simplest examples of such

1168-538: A lower drag, smaller diameter and lighter bullet, successful saboted projectile design has to include the resulting bullet stability characteristics. For example, simply inserting a commercially available 5.56mm (.224) bullet into a sabot that will fire it from a commercially available 7.62mm (.300) barrel may result in that 5.56mm bullet failing to achieve sufficient gyroscopic stability to fly accurately without tumbling. To achieve gyroscopic stability of longer bullets in smaller diameter requires faster rifling. Therefore, if

1241-402: A modest pressure. This pressure is high enough to provide useful propulsion of the payload (e.g. aerosol paint, deodorant, lubricant), but is low enough to be stored in an inexpensive metal can, and to not pose a safety hazard in case the can is ruptured. The mixture of liquid and gaseous propellant inside the can maintains a constant pressure, called the liquid's vapor pressure . As the payload

1314-429: A more efficient propellant , RPD-380 , boosting its muzzle velocity. The M829A3 round has a total mass of 22.3 kg (49 lb) and length of 892 mm (35.1 in). It uses 8.1 kg (18 lb) of RPD-380 stick propellant, accelerating the 10 kg (22 lb) sabot and depleted-uranium rod penetrator assembly, and a muzzle velocity of 1,555 m/s (5,100 ft/s). From patents submitted by Orbital ATK,

1387-506: A projectile, providing both structural support and obturation. Upon firing, when the sabot and projectile leave the muzzle of the gun, centrifugal force from the rotation of the projectile, due to barrel rifling, opens up the segments surrounding the projectile, rapidly presenting more surface area to air pressure, quickly releasing it. Although the use of cup sabots of various complexity are popular with rifle ammunition hand-loaders, in order to achieve significantly higher muzzle velocity with

1460-440: A propellant because they move at relativistic speed, i.e., the speed of light. In this case Newton's third Law of Motion is inadequate to model the physics involved and relativistic physics must be used. In chemical rockets, chemical reactions are used to produce energy which creates movement of a fluid which is used to expel the products of that chemical reaction (and sometimes other substances) as propellants. For example, in

1533-453: A properly designed sabot provides less parasitic mass than if the flight projectile were made full-bore, in particular providing dramatic improvement in muzzle velocity for APDS ( Armor-piercing discarding sabot ) and APFSDS ( Armor-piercing fin-stabilized discarding sabot ) ammunition. Seminal research on two important sabot configurations for long rod penetrators used in APFSDS ammunition, namely

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1606-430: A rear section which both centers the projectile, provides a structural "bulkhead", and seals propellant gases with an obturator ring around the outside diameter. Spindle sabots are the standard type used in modern large caliber armor-piercing ammunition. Three-petal spindle-type sabots are shown in the illustrations at the right of this paragraph. The "double-ramp" and "saddle-back" sabots used on modern APFSDS ammunition are

1679-432: A sabot is to provide a larger bulkhead structure that fills the entire bore area between an intentionally designed sub-caliber flight projectile and the barrel, giving a larger surface area for propellant gasses to act upon than just the base of the smaller flight projectile. Efficient aerodynamic design of a flight projectile does not always accommodate efficient interior ballistic design to achieve high muzzle velocity. This

1752-613: A sabot. In this example, using 1:10 rifling in 7.62mm restricts saboting to 5.56mm bullets that require 1:10 twist or slower, and this requirement will tend to restrict saboting to the shorter (and lighter) 5.56mm bullets. A base sabot has a one piece base which supports the bottom of the projectile, and separate pieces that surround the sides of the projectile and center it. The base sabot can have better and cleaner sabot/projectile separation than cup or expanding cup sabots for small arms ammunition, but may be more expensive to manufacture and assemble. In larger caliber APDS ammunition, based on

1825-489: A simple hydrogen/oxygen engine, hydrogen is burned (oxidized) to create H 2 O and the energy from the chemical reaction is used to expel the water (steam) to provide thrust. Often in chemical rocket engines, a higher molecular mass substance is included in the fuel to provide more reaction mass. Rocket propellant may be expelled through an expansion nozzle as a cold gas, that is, without energetic mixing and combustion, to provide small changes in velocity to spacecraft by

1898-451: A system are squeeze bottles for such liquids as ketchup and shampoo. However, compressed gases are impractical as stored propellants if they do not liquify inside the storage container, because very high pressures are required in order to store any significant quantity of gas, and high-pressure gas cylinders and pressure regulators are expensive and heavy. Liquefied gas propellants are gases at atmospheric pressure, but become liquid at

1971-492: A variety of usually ionized propellants, including atomic ions, plasma, electrons, or small droplets or solid particles as propellant. If the acceleration is caused mainly by the Coulomb force (i.e. application of a static electric field in the direction of the acceleration) the device is considered electrostatic. The types of electrostatic drives and their propellants: These are engines that use electromagnetic fields to generate

2044-407: Is a mass that is expelled from a vehicle, such as a rocket, in such a way as to create a thrust in accordance with Newton's third law of motion , and "propel" the vehicle forward. The engine that expels the propellant is called a reaction engine . Although the term "propellant" is often used in chemical rocket design to describe a combined fuel/propellant, propellants should not be confused with

2117-656: Is a further improvement, designed to defeat any future armor protection methods, like 'Kaktus' ERA, which was seen on the now canceled prototype tank, the Object 640 "Chiorny Oriol" (Black Eagle) (sometimes falsely named the T-80UM-2). It completed type classification standard in March 2003. Very little is publicly known about the round, perhaps due to export restrictions (see International Traffic in Arms Regulations (ITAR)). The M829A3 uses

2190-428: Is carried by a sabot during its acceleration in the gun barrel. The M829 dart has a ballistic nose and six tail fins made of aluminum . It is carried in the gun tube by a four-piece aluminum sabot , which separates into four "petals" soon after the round leaves the gun tube. The propulsion system uses an obturating case base with a semi-combustible cartridge wall. It has a total weight of 41.1 lb (18.6 kg) and

2263-440: Is depleted, the propellant vaporizes to fill the internal volume of the can. Liquids are typically 500-1000x denser than their corresponding gases at atmospheric pressure; even at the higher pressure inside the can, only a small fraction of its volume needs to be propellant in order to eject the payload and replace it with vapor. Vaporizing the liquid propellant to gas requires some energy, the enthalpy of vaporization , which cools

M829 - Misplaced Pages Continue

2336-435: Is especially true for arrow-type projectiles, which are long and thin for low drag efficiency, but too thin to shoot from a gun barrel of equal diameter to achieve high muzzle velocity. The physics of interior ballistics demonstrates why the use of a sabot is advantageous to achieve higher muzzle velocity with an arrow-type projectile. Propellant gasses generate high pressure, and the larger the base area that pressure acts upon

2409-436: Is generated by electricity: Nuclear reactions may be used to produce the energy for the expulsion of the propellants. Many types of nuclear reactors have been used/proposed to produce electricity for electrical propulsion as outlined above. Nuclear pulse propulsion uses a series of nuclear explosions to create large amounts of energy to expel the products of the nuclear reaction as the propellant. Nuclear thermal rockets use

2482-586: Is no longer in production and has been succeeded by the M829A1, M829A2, and M829A3. The corresponding training round is the M865, costing $ 1,121. The M829A1 (nicknamed the " Silver Bullet " by Operation Desert Storm tank crews) proved itself in 1991 against Iraqi T-55 and T-72 M tanks during Operation Desert Storm. The M829A1 round weighs 20.9 kg (46 lb) and has an overall length of 984 mm (38.7 in). The 7.9 kg (17 lb) of JA-19 propellant creates

2555-461: Is only used for training with a switched plastic sabot round. this is calculated from the 100-millimeter (3.9 in) steel tip adjoined to a 630-millimeter (24.8 in) DU body that is 25-millimeter (0.98 in) thick at 1550m/s (5085 fps) with a target RHA BHN of 250. The sabot is of composite material. This variant is unofficially referred to by Abrams tank crews as the "super sabot". Although the M829A3 fired from

2628-433: Is released by allowing the propellant to escape. Compressed fluid may also be used only as energy storage along with some other substance as the propellant, such as with a water rocket , where the energy stored in the compressed air is the fuel and the water is the propellant. In electrically powered spacecraft , electricity is used to accelerate the propellant. An electrostatic force may be used to expel positive ions, or

2701-475: Is similar to previous models but has a relocated skive joint placement for better crew-member safety during handling. The initial order for 2,501 M829A4 rounds in 2014 had a unit cost of $ 10,100 each. On 20 July 2015, Orbital ATK announced that the M829A4 had passed First Article Acceptance Testing and was entering production. On 12 October 2015, Orbital ATK announced the round had recently received type classification as

2774-420: Is the armor-piercing ammunition currently being produced by General Dynamics Ordnance and Tactical Systems for the 120 mm M256 gun of M1A1 and M1A2 tanks. It is a technology improvement over the M829A1. The new ammunition's performance gains, while classified, result from several new features. These include a special manufacturing process that improves the structural quality of the depleted uranium penetrator. This,

2847-481: Is used to compress the air is stored until it is released by allowing the propellant to escape. Compressed fluid may also be used only as energy storage along with some other substance as the propellant, such as with a water rocket , where the energy stored in the compressed air is the fuel and the water is the propellant. Proposed photon rockets would use the relativistic momentum of photons to create thrust. Even though photons do not have mass, they can still act as

2920-621: Is used to defeat the ERA by detonating it early, causing the resulting ERA bursting plate to only partially affect the main DU rod which is used to complete the penetration through armor. The resulting muzzle energy is 12.1 MJ (8.9 million ft⋅lbf) The penetration as per the Lanz Odermatt calculator is about a total penetration of 680-millimeters (26.7717 in) up to possibly 720-millimetres of RHA to account for any discrepancies in measurement. The M829A3

2993-525: The Lorentz force may be used to expel negative ions and electrons as the propellant. Electrothermal engines use the electromagnetic force to heat low molecular weight gases (e.g. hydrogen, helium, ammonia) into a plasma and expel the plasma as propellant. In the case of a resistojet rocket engine, the compressed propellant is simply heated using resistive heating as it is expelled to create more thrust. In chemical rockets and aircraft, fuels are used to produce an energetic gas that can be directed through

M829 - Misplaced Pages Continue

3066-525: The Lorentz force may be used to expel negative ions and electrons as the propellant. Electrothermal engines use the electromagnetic force to heat low molecular weight gases (e.g. hydrogen, helium, ammonia) into a plasma and expel the plasma as propellant. In the case of a resistojet rocket engine, the compressed propellant is simply heated using resistive heating as it is expelled to create more thrust. In chemical rockets and aircraft, fuels are used to produce an energetic gas that can be directed through

3139-532: The M829 series of anti-tank projectiles). Sabot-type shotgun slugs were marketed in the United States from about 1985, and became legal for hunting in most U.S. states. When used with a rifled slug barrel , they are very much more accurate than normal shotgun slugs. A cup sabot supports the base and rear end of a projectile, and the cup material alone can provide both structural support and barrel obturation. When

3212-441: The fuel that is used by an engine to produce the energy that expels the propellant. Even though the byproducts of substances used as fuel are also often used as a reaction mass to create the thrust, such as with a chemical rocket engine, propellant and fuel are two distinct concepts. In electrically powered spacecraft , electricity is used to accelerate the propellant. An electrostatic force may be used to expel positive ions, or

3285-404: The fuel that is used by an engine to produce the energy that expels the propellant. Even though the byproducts of substances used as fuel are also often used as a reaction mass to create the thrust, such as with a chemical rocket engine, propellant and fuel are two distinct concepts. Vehicles can use propellants to move by ejecting a propellant backwards which creates an opposite force that moves

3358-506: The "saddle-back" and "double-ramp" sabot was performed by the US Army Ballistics Research Laboratory during the development and improvement of modern 105mm and 120mm kinetic energy APFSDS penetrators and published in 1978, permitted by the significant advancement in the computerized finite element method in structural mechanics at that time; and now represents the existing fielded technology standard. (See for example

3431-460: The 44-caliber M256 gun has a lower muzzle velocity than 120 mm shells fired from the Rheinmetall 55-caliber gun barrel or Russian 2A46 125 mm gun ammunition, it uses a larger penetrator with increased mass to increase imparted kinetic energy. The A4 (formerly E4) variant was under development by General Dynamics Ordnance & Tactical Systems and Alliant Techsystems (ATK) until ATK received

3504-438: The M829A4 and was awarded a full-rate production contract to begin in early 2016. Sabot (firearms) The sabot component in projectile design is the relatively thin, tough and deformable seal known as a driving band or obturation ring needed to trap propellant gases behind a projectile, and also keep the projectile centered in the barrel, when the outer shell of the projectile is only slightly smaller in diameter than

3577-417: The barrel as the projectile is forced from the chamber into the barrel. Sabots use driving bands and obturators, because the same manufacturing tolerance issues exist when sealing the saboted projectile in the barrel, but the sabot itself is a more substantial structural component of the in-bore projectile configuration. Refer to the two armor-piercing fin-stabilized discarding sabot ( APFSDS ) pictures to see

3650-564: The burning of the fuel and, as a consequence, thrust vs time profile. There are three types of burns that can be achieved with different grains. There are four different types of solid fuel/propellant compositions: In rockets, three main liquid bipropellant combinations are used: cryogenic oxygen and hydrogen, cryogenic oxygen and a hydrocarbon, and storable propellants. Propellant combinations used for liquid propellant rockets include: Common monopropellant used for liquid rocket engines include: Electrically powered reactive engines use

3723-437: The caliber of the barrel. Driving bands and obturators are used to seal these full-bore projectiles in the barrel because of manufacturing tolerances; there always exists some gap between the projectile outer diameter and the barrel inner diameter, usually a few thousandths of an inch; enough of a gap for high pressure gasses to slip by during firing. Driving bands and obturator rings are made from material that will deform and seal

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3796-620: The cartridge case, an obturator or driving band. When the projectile is fired, the sabot blocks the gas, provides significant structural support against launch acceleration, and carries the projectile down the barrel. When the sabot reaches the end of the barrel, the shock of hitting still air pulls the parts of the sabot away from the projectile, allowing the projectile to continue in flight. Modern sabots are made from high strength aluminum and graphite fiber reinforced epoxy. They are used primarily to fire long rods of very dense materials, such as tungsten heavy alloy and depleted uranium. (see for example

3869-432: The cup, expanding cup, and base sabot concepts, significantly more complex assemblies are required. A spindle sabot uses a set of at least two and upwards of four matched longitudinal rings or "petals" which have a center section in contact with a long arrow-type projectile; a front section or "bore-rider" which centers that projectile in the barrel and provides an air scoop to assist in sabot separation upon muzzle exit, and

3942-507: The development of the M829 series of anti-tank projectiles beginning with the base model M829 in the early 1980s, to the 2016 M829A4 model, employing ever longer "double-ramp" sabots). Upon muzzle exit, the sabot is discarded, and the smaller flight projectile flies to the target with less drag resistance than a full-bore projectile. In this manner, very high velocity and slender, low drag projectiles can be fired more efficiently, (see external ballistics and terminal ballistics ). Nevertheless,

4015-652: The disadvantage of being flammable . Nitrous oxide and carbon dioxide are also used as propellants to deliver foodstuffs (for example, whipped cream and cooking spray ). Medicinal aerosols such as asthma inhalers use hydrofluoroalkanes (HFA): either HFA 134a (1,1,1,2,-tetrafluoroethane) or HFA 227 (1,1,1,2,3,3,3-heptafluoropropane) or combinations of the two. More recently, liquid hydrofluoroolefin (HFO) propellants have become more widely adopted in aerosol systems due to their relatively low vapor pressure, low global warming potential (GWP), and nonflammability. The practicality of liquified gas propellants allows for

4088-414: The fuel to provide more reaction mass. Rocket propellant may be expelled through an expansion nozzle as a cold gas, that is, without energetic mixing and combustion, to provide small changes in velocity to spacecraft by the use of cold gas thrusters , usually as maneuvering thrusters. To attain a useful density for storage, most propellants are stored as either a solid or a liquid. A rocket propellant

4161-404: The greater the net force on that surface. Force (pressure times area) provides an acceleration to the mass of the projectile. Therefore, for a given pressure and barrel diameter, a lighter projectile can be driven from a barrel to a higher muzzle velocity than a heavier projectile. However, a lighter projectile may not fit in the barrel, because it is too thin. To make up this difference in diameter,

4234-461: The heat of a nuclear reaction to heat a propellant. Usually the propellant is hydrogen because the force is a function of the energy irrespective of the mass of the propellant, so the lightest propellant (hydrogen) produces the greatest specific impulse . A photonic reactive engine uses photons as the propellant and their discrete relativistic energy to produce thrust. Compressed fluid or compressed gas propellants are pressurized physically, by

4307-400: The need for sabot ramps to also support the steel flight projectile. Propellant A propellant (or propellent ) is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion , and "propel" a vehicle, projectile , or fluid payload. In vehicles, the engine that expels the propellant is called

4380-402: The newly synthesized bishomocubane based compounds are under consideration in the research stage as both solid and liquid propellants of the future. Solid fuel/propellants are used in forms called grains . A grain is any individual particle of fuel/propellant regardless of the size or shape. The shape and size of a grain determines the burn time, amount of gas, and rate of produced energy from

4453-512: The penetrator is composed of two sections, an approximately 100-millimeter-long (3.9 in) steel tip and the rest composed of a 630-millimeter (24.8 in) depleted uranium rod with aluminum fins with a tracer base. The penetrator diameter was also increased from 22 mm (0.87 in) to 25 mm (0.98 in), improving penetrator strength by 67% significantly increasing its resistance to ERA bursting plates as used in Russian ERA. The steel tip

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4526-428: The projectile near the front, with an obturator sealing gases from escaping past it, and centering the front of the projectile. The former Soviet Union favored armor-piercing sabot projectiles using ring sabots, which performed acceptably for that era, manufactured from high strength steel for both the long rod penetrator and ring sabot. The strength of the steel ring was sufficient to withstand launch accelerations without

4599-522: The propellant). Chlorofluorocarbons (CFCs) were once often used as propellants, but since the Montreal Protocol came into force in 1989, they have been replaced in nearly every country due to the negative effects CFCs have on Earth's ozone layer . The most common replacements of CFCs are mixtures of volatile hydrocarbons , typically propane , n- butane and isobutane . Dimethyl ether (DME) and methyl ethyl ether are also used. All these have

4672-402: The propellant. Compressed fluid may also be used as a simple vehicle propellant, with the potential energy that is stored in the compressed fluid used to expel the fluid as the propellant. The energy stored in the fluid was added to the system when the fluid was compressed, such as compressed air . The energy applied to the pump or thermal system that is used to compress the air is stored until it

4745-546: The resulting propellant product has more mass than the fuel carried on the vehicle. Proposed photon rockets would use the relativistic momentum of photons to create thrust. Even though photons do not have mass, they can still act as a propellant because they move at relativistic speed, i.e., the speed of light. In this case Newton's third Law of Motion is inadequate to model the physics involved and relativistic physics must be used. In chemical rockets, chemical reactions are used to produce energy which creates movement of

4818-422: The resulting propellant product has more mass than the fuel carried on the vehicle. The propellant or fuel may also simply be a compressed fluid, with the potential energy that is stored in the compressed fluid used to expel the fluid as the propellant. The energy stored in the fluid was added to the system when the fluid was compressed, such as compressed air . The energy applied to the pump or thermal system that

4891-401: The sabot and projectile exit the muzzle of the gun, air pressure alone on the sabot forces the sabot to release the projectile. Cup sabots are found typically in small arms ammunition, smooth-bore shotgun and smooth-bore muzzleloader projectiles. Used typically in rifled small arms (SLAP, shotguns, and muzzleloaders), an expanding cup sabot has a one piece sabot surrounding the base and sides of

4964-415: The substantial material nature of a sabot to fill the bore diameter around the sub-caliber arrow-type flight projectile, compared to the very small gap sealed by a driving band or obturator to mitigate what is known classically as windage . More detailed cutaways of the internal structural complexity of advanced APFSDS saboted long rod penetrator projectiles can be found in #External links . The function of

5037-413: The system. This is usually insignificant, although it can sometimes be an unwanted effect of heavy usage (as the system cools, the vapor pressure of the propellant drops). However, in the case of a freeze spray , this cooling contributes to the desired effect (although freeze sprays may also contain other components, such as chloroethane , with a lower vapor pressure but higher enthalpy of vaporization than

5110-551: The use of cold gas thrusters , usually as maneuvering thrusters. To attain a useful density for storage, most propellants are stored as either a solid or a liquid. Propellants may be energized by chemical reactions to expel solid, liquid or gas. Electrical energy may be used to expel gases, plasmas, ions, solids or liquids. Photons may be used to provide thrust via relativistic momentum. Propellants that explode in operation are of little practical use currently, although there have been experiments with Pulse Detonation Engines . Also

5183-424: The use of new composites for the sabot, and a new propellant provide superior penetrator performance. Combined, these features increase the muzzle velocity of the M829A2 to approximately 100 m/s greater than the M829A1's (up to approximately 1,675 m/s) while operating at slightly lower pressure. The projectile's length is 780 mm, its mass 9 kg. On 6 May 2014, the U.S. Army announced that it awarded

5256-413: The vehicle forward. Projectiles can use propellants that are expanding gases which provide the motive force to set the projectile in motion. Aerosol cans use propellants which are fluids that are compressed so that when the propellant is allowed to escape by releasing a valve, the energy stored by the compression moves the propellant out of the can and that propellant forces the aerosol payload out along with

5329-834: The weight of the sabot represents parasitic mass that must also be accelerated to muzzle velocity, but does not contribute to the terminal ballistics of the flight projectile. For this reason, great emphasis is placed on selecting strong yet lightweight structural materials for the sabot, and configuring the sabot geometry to efficiently employ these parasitic materials at minimum weight penalty. Made of some lightweight material (usually high strength plastic in small caliber rifles, (see SLAP Saboted light armor penetrator ), shotguns and muzzle loader ammunition; aluminium, steel, and carbon fiber reinforced plastic for modern anti-tank kinetic energy ammunition; and, in classic times, wood or papier-mâché – in muzzle loading cannons). The sabot usually consists of several longitudinal pieces held in place by

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