CA2990862C - Propelling charge system for artillery shells - Google Patents
Propelling charge system for artillery shells Download PDFInfo
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- CA2990862C CA2990862C CA2990862A CA2990862A CA2990862C CA 2990862 C CA2990862 C CA 2990862C CA 2990862 A CA2990862 A CA 2990862A CA 2990862 A CA2990862 A CA 2990862A CA 2990862 C CA2990862 C CA 2990862C
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- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
- C06B45/18—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component
- C06B45/20—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component the component base containing an organic explosive or an organic thermic component
- C06B45/28—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component the component base containing an organic explosive or an organic thermic component the component base containing nitrocellulose and nitroglycerine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
- F42B5/38—Separately-loaded propellant charges, e.g. cartridge bags
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- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B25/00—Compositions containing a nitrated organic compound
- C06B25/18—Compositions containing a nitrated organic compound the compound being nitrocellulose present as 10% or more by weight of the total composition
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- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
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- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
- C06B45/18—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component
- C06B45/20—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component the component base containing an organic explosive or an organic thermic component
- C06B45/22—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component the component base containing an organic explosive or an organic thermic component the coating containing an organic compound
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- Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)
Abstract
The present application relates to a propellant charge system for firing artillery shells comprising at least two partial charges. The partial charges each have one type of powder, which comprises nitrocellulose, at least one crystalline energy carrier and at least a first inert plasticiser. At least one partial charge has a first type of powder and the at least one further partial charge has a second type of powder. The second type of powder has between 2 and 10 percent by weight of a second inert plasticiser in the region of zones near the surface, to a maximum depth of penetration of 400 micrometres, while the first type of powder has no second inert plasticiser in zones near the surface.
Description
PROPELLING CHARGE SYSTEM FOR ARTILLERY SHELLS
Technical field The invention relates to a propelling charge system for firing artillery shells, more particularly for 105 mm howitzers, built on a combination of two different powder types, one with diffused inert plasticizer in the near-surface zones and the other essentially without diffused inert plasticizer.
Prior art A howitzer is understood to refer to a piece of artillery characterized by a relatively short barrel and the possibility of firing relatively heavy shells with relatively low charge masses, wherein the shells can reach high trajectories and are launched at a steep firing angle. For over 100 years, 105 nun howitzer systems, also referred to as field artillery, have enjoyed continuous popularity with many armies around the globe. This type of weapon became massively more widespread during the course of World War I, and since then, battlefields have been characterized by the destructive power of artillery weapons systems.
Field artillery cannons are important instruments for achieving the desired destructive power.
The ammunition to be fired is equally important for achieving this destructive effect. This weapon thus makes it possible to transport a shell to the target area reliably and with pinpoint accuracy, while the desired target effect is produced by the correspondingly configured ammunition. For a long time, the only known target effect of field artillery was maximum destruction. However, new technological possibilities have now made the scenarios at the point of impact more varied, allowing a wide variety of effects to be achieved at the target area. An example of such an effect, in addition to the maximum possible destruction, is the provision of a smokescreen in order to protect one's own troops.
For many years, the 105 mm howitzers M101 and M2 were the light field howitzers of the US
military and were widely used during World War II in the European and Pacific theaters of operations. The 105 mm family was completed by the air-chargeable version M3, which was based on the M2 system but had a barrel that was shorter by 690 mm and a more effective recoil brake. The M3 howitzer was capable of using the same ammunition as the M2, but because of its shorter barrel, more highly explosive powder had to be used as the propellant.
Production of the M2 and M3 systems was begun in 1941. When deployed, these weapons systems showed impressive results due to their precise target accuracy and highly lethal effect.
Because of these qualities, combined with the fact that they were mass produced, this family of weapons became the standard howitzer system used in many countries after the war, and they remain in widespread active use today. Overall, the M101 howitzer system is used worldwide by a total of 67 different armies and is thus the most successful artillery system ever produced. Over time, the original types of ammunition developed into the standard for various new ammunition variants of later systems that were tailored to the specific requirements of the country in question.
The M101 system has been out of service in the US for some time now. As its successor, the howitzer M102A1, which had been developed earlier, was introduced by the US
armed forces in March of 1966. In many countries, however, the M101 and M2 systems, together with the more recent M102A1 systems, continue to be in active use. France and Vietnam used such systems during the First Indochina War, as did the North Vietnamese Army.
Modernized M102A1 systems continue to be actively used by the People's Army of Vietnam today.
Technical field The invention relates to a propelling charge system for firing artillery shells, more particularly for 105 mm howitzers, built on a combination of two different powder types, one with diffused inert plasticizer in the near-surface zones and the other essentially without diffused inert plasticizer.
Prior art A howitzer is understood to refer to a piece of artillery characterized by a relatively short barrel and the possibility of firing relatively heavy shells with relatively low charge masses, wherein the shells can reach high trajectories and are launched at a steep firing angle. For over 100 years, 105 nun howitzer systems, also referred to as field artillery, have enjoyed continuous popularity with many armies around the globe. This type of weapon became massively more widespread during the course of World War I, and since then, battlefields have been characterized by the destructive power of artillery weapons systems.
Field artillery cannons are important instruments for achieving the desired destructive power.
The ammunition to be fired is equally important for achieving this destructive effect. This weapon thus makes it possible to transport a shell to the target area reliably and with pinpoint accuracy, while the desired target effect is produced by the correspondingly configured ammunition. For a long time, the only known target effect of field artillery was maximum destruction. However, new technological possibilities have now made the scenarios at the point of impact more varied, allowing a wide variety of effects to be achieved at the target area. An example of such an effect, in addition to the maximum possible destruction, is the provision of a smokescreen in order to protect one's own troops.
For many years, the 105 mm howitzers M101 and M2 were the light field howitzers of the US
military and were widely used during World War II in the European and Pacific theaters of operations. The 105 mm family was completed by the air-chargeable version M3, which was based on the M2 system but had a barrel that was shorter by 690 mm and a more effective recoil brake. The M3 howitzer was capable of using the same ammunition as the M2, but because of its shorter barrel, more highly explosive powder had to be used as the propellant.
Production of the M2 and M3 systems was begun in 1941. When deployed, these weapons systems showed impressive results due to their precise target accuracy and highly lethal effect.
Because of these qualities, combined with the fact that they were mass produced, this family of weapons became the standard howitzer system used in many countries after the war, and they remain in widespread active use today. Overall, the M101 howitzer system is used worldwide by a total of 67 different armies and is thus the most successful artillery system ever produced. Over time, the original types of ammunition developed into the standard for various new ammunition variants of later systems that were tailored to the specific requirements of the country in question.
The M101 system has been out of service in the US for some time now. As its successor, the howitzer M102A1, which had been developed earlier, was introduced by the US
armed forces in March of 1966. In many countries, however, the M101 and M2 systems, together with the more recent M102A1 systems, continue to be in active use. France and Vietnam used such systems during the First Indochina War, as did the North Vietnamese Army.
Modernized M102A1 systems continue to be actively used by the People's Army of Vietnam today.
2 M102A1/M101 howitzers were also used in former Yugoslavia, and 50 of these weapons are still being used in Croatia.
A further example of a 105 mm howitzer system that remains in widespread use worldwide is the L118 Light Gun. These are externally purchased howitzers that were originally produced by the British Army in the 1970s and subsequently widely exported.
As a further widely-used 105 mm howitzer system, one should also mention the LG1. This modern system is also externally produced, is highly valued for its light weight and high target accuracy accompanied by its relatively long range, and is produced by GIAT
Industries (now the Nexter Group). This system is currently in active use by the armies of Belgium, Canada, Colombia, Indonesia, Singapore and Thailand, among other countries.
As a last example, one should mention the system Oto Melara Mod 56. This is a 105 mm howitzer of Italian origin that can use ammunition such as that of the US Ml.
The Oto Melara 105 mm Mod 56 howitzer was put into operation in the 1950s. Because of its light weight, it was primarily used by the Mountain Artillery of the Italian Alpini Brigade. It is still possible .. today to transport this weapon via helicopter without dismantling it, which aroused the interest of other, primarily western nations in the 1960s. Overall, the Mod 56 howitzer was used in more then 30 countries worldwide. This weapon is currently in active use in at least 23 countries, including Argentina, Brazil, Chile, Greece, Malaysia, Mexico, Peru, the Philippines, Saudi Arabia, Spain, Thailand and Venezuela.
As described above, large numbers of 105 mm howitzers are therefore in active use worldwide, with these largely consisting of the various types described above.
Although all of these systems use the same caliber of 105 mm, each of the various howitzer types requires ammunition specifically tailored to the system in question. This is due to differences in the barrel structure (length, gas pressure limits), ballistic table, or available charge volume.
A further example of a 105 mm howitzer system that remains in widespread use worldwide is the L118 Light Gun. These are externally purchased howitzers that were originally produced by the British Army in the 1970s and subsequently widely exported.
As a further widely-used 105 mm howitzer system, one should also mention the LG1. This modern system is also externally produced, is highly valued for its light weight and high target accuracy accompanied by its relatively long range, and is produced by GIAT
Industries (now the Nexter Group). This system is currently in active use by the armies of Belgium, Canada, Colombia, Indonesia, Singapore and Thailand, among other countries.
As a last example, one should mention the system Oto Melara Mod 56. This is a 105 mm howitzer of Italian origin that can use ammunition such as that of the US Ml.
The Oto Melara 105 mm Mod 56 howitzer was put into operation in the 1950s. Because of its light weight, it was primarily used by the Mountain Artillery of the Italian Alpini Brigade. It is still possible .. today to transport this weapon via helicopter without dismantling it, which aroused the interest of other, primarily western nations in the 1960s. Overall, the Mod 56 howitzer was used in more then 30 countries worldwide. This weapon is currently in active use in at least 23 countries, including Argentina, Brazil, Chile, Greece, Malaysia, Mexico, Peru, the Philippines, Saudi Arabia, Spain, Thailand and Venezuela.
As described above, large numbers of 105 mm howitzers are therefore in active use worldwide, with these largely consisting of the various types described above.
Although all of these systems use the same caliber of 105 mm, each of the various howitzer types requires ammunition specifically tailored to the system in question. This is due to differences in the barrel structure (length, gas pressure limits), ballistic table, or available charge volume.
3 Despite these differences, however, all of these howitzer systems have common features, i.e.
fundamental principles, that apply to every type of ammunition. Of particular relevance here is the fact that combat against a target generally involves indirect fire, i.e.
the shells are fired upward, causing the projectile to follow a parabolic flight path. In addition, an artillery charge system is composed of a differing number of individual charges in order to cover the widest possible range of effect, with the number of charges corresponding to the number of zones of the respective ballistic table.
A common feature of all currently used 105 mm howitzer systems is thus that a charge system is used for firing ammunition composed of multiple individual charges. If only a few individual charges, e.g. charge 1 or charge 2, are used, the two lowest zones of the ballistic table can be covered with fire. However, if the maximum provided number of charges is loaded, e.g. all seven possible partial charges, the weapon can be fired with the maximum possible range, i.e. the highest zone of the ballistic table can be covered with fire.
The conditions under which the powder of a propelling charge burns off vary widely .. depending on the charge used. In charge 1, which is used against the closest targets (zone 1 of the ballistic table), the powder mass is lowest relative to the shell mass.
There is thus only a relatively small amount of gas available for accelerating the shell in the barrel of the weapon, with the result that the pressure conditions prevailing during powder conversion are at a relatively low level. This means that the powder for low charges must be configured such that .. complete burn-off occurs at the relatively low pressure in order to minimize the discharge of unburned powder particles. In use of the highest possible charge for the respective howitzer system, however, the maximum chargeable amount of powder is used. This allows the maximum possible amount of gas to be released in the barrel for accelerating the shell, with the result that powder burn-off takes place at a relatively high level of pressure, which can be
fundamental principles, that apply to every type of ammunition. Of particular relevance here is the fact that combat against a target generally involves indirect fire, i.e.
the shells are fired upward, causing the projectile to follow a parabolic flight path. In addition, an artillery charge system is composed of a differing number of individual charges in order to cover the widest possible range of effect, with the number of charges corresponding to the number of zones of the respective ballistic table.
A common feature of all currently used 105 mm howitzer systems is thus that a charge system is used for firing ammunition composed of multiple individual charges. If only a few individual charges, e.g. charge 1 or charge 2, are used, the two lowest zones of the ballistic table can be covered with fire. However, if the maximum provided number of charges is loaded, e.g. all seven possible partial charges, the weapon can be fired with the maximum possible range, i.e. the highest zone of the ballistic table can be covered with fire.
The conditions under which the powder of a propelling charge burns off vary widely .. depending on the charge used. In charge 1, which is used against the closest targets (zone 1 of the ballistic table), the powder mass is lowest relative to the shell mass.
There is thus only a relatively small amount of gas available for accelerating the shell in the barrel of the weapon, with the result that the pressure conditions prevailing during powder conversion are at a relatively low level. This means that the powder for low charges must be configured such that .. complete burn-off occurs at the relatively low pressure in order to minimize the discharge of unburned powder particles. In use of the highest possible charge for the respective howitzer system, however, the maximum chargeable amount of powder is used. This allows the maximum possible amount of gas to be released in the barrel for accelerating the shell, with the result that powder burn-off takes place at a relatively high level of pressure, which can be
4 as high as the system limit of the 105 mm howitzer system used. As powder burn-off is significantly increased by higher pressure, the powder used in higher charges must be configured correspondingly, i.e. it must react significantly more slowly compared to the powders of low charges.
A drawback of the known propellant systems for artillery shells is that important ballistic characterizing data such as muzzle velocity and peak gas pressure are affected by the ambient temperature, wherein the lowest values occur at cold temperatures and these values increase continuously with rising temperature. Ambient temperature therefore has a direct effect on the performance and accuracy of the weapon.
A trend has also recently become established in which a significant majority of armed conflicts are taking place in hot climatic zones. Examples of this include Iraq, Afghanistan and Somalia. In order to achieve the high internal ballistic performance required, large amounts of explosive oils such as dinitrotoluene (DNT) and plasticizers such as dibutylphthalate (DBP) must be added to the propelling charge powders. However, such propellants have been found to be unsuitable under high thermal loads because pronounced changes in muzzle velocity and peak gas pressure occur after storage for several months. This effect reduces the first-hit probability, and because of the resulting increase in peak gas pressure of up to 50%, this constitutes a high safety risk during firing, because the pressure limit of the weapon can be significantly exceeded in an uncontrolled manner. However, exposure to high temperatures in hot climatic zones also sharply impairs the thermal stability of an explosive-oil-containing propellant in that, among other factors, the stabilizer is used up much more quickly, which increases the risk of uncontrolled autocatalysis due to aging. The detonation reaction of a propellant caused thereby can destroy an entire ammunition depot and injure personnel. A
A drawback of the known propellant systems for artillery shells is that important ballistic characterizing data such as muzzle velocity and peak gas pressure are affected by the ambient temperature, wherein the lowest values occur at cold temperatures and these values increase continuously with rising temperature. Ambient temperature therefore has a direct effect on the performance and accuracy of the weapon.
A trend has also recently become established in which a significant majority of armed conflicts are taking place in hot climatic zones. Examples of this include Iraq, Afghanistan and Somalia. In order to achieve the high internal ballistic performance required, large amounts of explosive oils such as dinitrotoluene (DNT) and plasticizers such as dibutylphthalate (DBP) must be added to the propelling charge powders. However, such propellants have been found to be unsuitable under high thermal loads because pronounced changes in muzzle velocity and peak gas pressure occur after storage for several months. This effect reduces the first-hit probability, and because of the resulting increase in peak gas pressure of up to 50%, this constitutes a high safety risk during firing, because the pressure limit of the weapon can be significantly exceeded in an uncontrolled manner. However, exposure to high temperatures in hot climatic zones also sharply impairs the thermal stability of an explosive-oil-containing propellant in that, among other factors, the stabilizer is used up much more quickly, which increases the risk of uncontrolled autocatalysis due to aging. The detonation reaction of a propellant caused thereby can destroy an entire ammunition depot and injure personnel. A
5 modern propellant system for 105 mm howitzers should therefore provide the high performance required without containing explosive oil.
A possible approach for solving this problem is known and involves mixing a crystalline energy carrier, for example nitramine compounds such as e.g. RDX or HMX into the particle .. matrix. In this manner, high internal ballistic performance can be achieved without the use of explosive oils (US 8,353,994 B2; WO 2014/117280 Al). In addition, it is known that the temperature characteristics of a propelling charge powder can be selectively improved by means of surface treatment. By suitably selecting the treatment parameters, it is thus possible to attenuate both the decrease in the cold curves and the increase in the heat curves of muzzle velocity and peak gas pressure (US 7,473,330 B2; US 8,353,994 B2; WO
2014/117280 Al).
Of significance in this context is that the parameters of the surface treatment applied, more particularly the amount of camphor used, have different effects on temperature coefficients depending on the class of weapon in question. For example, in medium-caliber weapons, an increase in the amount of camphor causes flattening of the heat curves of muzzle velocity and peak gas pressure, i.e. the increase in pressure is attenuated (US 8,353,994 B2). In mortar weapons, in contrast, an increase in the amount of camphor has the opposite effect, i.e. the heat curves of muzzle velocity and peak gas pressure become steeper or the increase in pressure becomes sharper respectively (WO 20 14/1 17280 Al). It has been found in practice that in medium-caliber systems, the amounts of camphor must typically be adjusted to 3-5 wt.% in order to minimize this steepening of the heat curves. In mortar systems, however, the amount of camphor must be set as low as possible (<0.5%) or the substance must be omitted altogether in order for the heat curves of muzzle velocity and peak gas pressure to show the smallest increase possible.
A possible approach for solving this problem is known and involves mixing a crystalline energy carrier, for example nitramine compounds such as e.g. RDX or HMX into the particle .. matrix. In this manner, high internal ballistic performance can be achieved without the use of explosive oils (US 8,353,994 B2; WO 2014/117280 Al). In addition, it is known that the temperature characteristics of a propelling charge powder can be selectively improved by means of surface treatment. By suitably selecting the treatment parameters, it is thus possible to attenuate both the decrease in the cold curves and the increase in the heat curves of muzzle velocity and peak gas pressure (US 7,473,330 B2; US 8,353,994 B2; WO
2014/117280 Al).
Of significance in this context is that the parameters of the surface treatment applied, more particularly the amount of camphor used, have different effects on temperature coefficients depending on the class of weapon in question. For example, in medium-caliber weapons, an increase in the amount of camphor causes flattening of the heat curves of muzzle velocity and peak gas pressure, i.e. the increase in pressure is attenuated (US 8,353,994 B2). In mortar weapons, in contrast, an increase in the amount of camphor has the opposite effect, i.e. the heat curves of muzzle velocity and peak gas pressure become steeper or the increase in pressure becomes sharper respectively (WO 20 14/1 17280 Al). It has been found in practice that in medium-caliber systems, the amounts of camphor must typically be adjusted to 3-5 wt.% in order to minimize this steepening of the heat curves. In mortar systems, however, the amount of camphor must be set as low as possible (<0.5%) or the substance must be omitted altogether in order for the heat curves of muzzle velocity and peak gas pressure to show the smallest increase possible.
6 Nitroglycerin-containing propellants, predominantly so-called ball powder, are only used to a relatively minor extent in artillery, being used only in special applications such as e.g. high-performance charges (unit charges). The most widespread powder type used in 105 mm artillery is composed of a particle matrix essentially containing nitrocellulose, approximately 10% dinitrotoluene (DNT) and approximately 5% of the plasticizer dibutylphthalate (DBP).
However, the ballistic stability of this powder type is insufficient because of diffusion of the plasticizer, particularly when used in hot climatic zones. The two known types of nitroglycerin and dinitrotoluene containing powder types for 105 mm artillery applications can both contain dibutylphthalate as a plasticizer. However, dinitrotoluene and dibutylphthalate are not compatible with Regulation (EC) No. 1907/2006 (REACH) and therefore will no longer be allowed for use in the European Union.
The propelling charge system to be fired can generally also be used in other caliber ranges, e.g. in 155 mm systems. For this purpose, the wall thicknesses of the powders used would have to be adapted in a manner known to persons skilled in the art.
Description of the invention The object of the invention is to provide a propelling charge belonging to the technical field mentioned above in which the peak gas pressure and thus the muzzle velocity show the smallest possible variation over a broad temperature range, more particularly between -46 C and 63 C, compared to the peak gas pressure and muzzle velocity at 21 C.
More particularly, the peak gas pressure of the highest charge possible for achieving the maximum range at an ambient temperature of 63 C should not be substantially higher than at an ambient temperature of 21 C. In addition, powder burn-off should take place without leaving any residue, even in the case of low charges and an ambient temperature in the range of -46 C,
However, the ballistic stability of this powder type is insufficient because of diffusion of the plasticizer, particularly when used in hot climatic zones. The two known types of nitroglycerin and dinitrotoluene containing powder types for 105 mm artillery applications can both contain dibutylphthalate as a plasticizer. However, dinitrotoluene and dibutylphthalate are not compatible with Regulation (EC) No. 1907/2006 (REACH) and therefore will no longer be allowed for use in the European Union.
The propelling charge system to be fired can generally also be used in other caliber ranges, e.g. in 155 mm systems. For this purpose, the wall thicknesses of the powders used would have to be adapted in a manner known to persons skilled in the art.
Description of the invention The object of the invention is to provide a propelling charge belonging to the technical field mentioned above in which the peak gas pressure and thus the muzzle velocity show the smallest possible variation over a broad temperature range, more particularly between -46 C and 63 C, compared to the peak gas pressure and muzzle velocity at 21 C.
More particularly, the peak gas pressure of the highest charge possible for achieving the maximum range at an ambient temperature of 63 C should not be substantially higher than at an ambient temperature of 21 C. In addition, powder burn-off should take place without leaving any residue, even in the case of low charges and an ambient temperature in the range of -46 C,
7 wherein the muzzle velocities achieved should not deviate substantially from the muzzle velocity at an ambient temperature of 21 C. Finally, the propelling charge system should show higher chemical and ballistic stability without requiring the use of any toxic substances. In addition, the propelling charge system should show a high thermal conversion rate with low charges, while the highest possible thermal efficiency should be achieved with high charges.
According to the invention, a propelling charge system for firing artillery shells comprises at least two partial charges. Each partial charge has one powder type as a propellant, said charge comprising at least one crystalline energy carrier and at least one first inert plasticizer. At least one partial charge is composed of a first powder type, and the at least one further partial charge is composed of a second powder type. In the area of the near-surface zones to a penetration depth of at most 400 m, the second powder type contains between 2 and 10 wt.%
of a second inert plasticizer, while the first powder type contains no second inert plasticizer in the near-surface zones. "No second inert plasticizer" is understood to refer to a concentration of the second inert plasticizer of 0% in the near-surface zones of the first powder type.
Surprisingly, it has now been found that a propelling charge system for firing artillery shells, more particularly for 105 mm howitzers, built on the combination of two different powder types with a second inert plasticizer and without a second inert plasticizer in the near-surface zones, provides internal ballistic properties that are favorable to an unanticipated degree.
As the second inert plasticizer is preferably diffused in the near-surface zones, the following application refers to the use of the second powder type with a diffused second inert plasticizer and the first powder type without a diffused second inert plasticizer.
Ordinarily, the lowest muzzle velocities and peak gas pressures occur at the lowest firing temperature and rise continuously with increasing firing temperature, i.e. the highest values
According to the invention, a propelling charge system for firing artillery shells comprises at least two partial charges. Each partial charge has one powder type as a propellant, said charge comprising at least one crystalline energy carrier and at least one first inert plasticizer. At least one partial charge is composed of a first powder type, and the at least one further partial charge is composed of a second powder type. In the area of the near-surface zones to a penetration depth of at most 400 m, the second powder type contains between 2 and 10 wt.%
of a second inert plasticizer, while the first powder type contains no second inert plasticizer in the near-surface zones. "No second inert plasticizer" is understood to refer to a concentration of the second inert plasticizer of 0% in the near-surface zones of the first powder type.
Surprisingly, it has now been found that a propelling charge system for firing artillery shells, more particularly for 105 mm howitzers, built on the combination of two different powder types with a second inert plasticizer and without a second inert plasticizer in the near-surface zones, provides internal ballistic properties that are favorable to an unanticipated degree.
As the second inert plasticizer is preferably diffused in the near-surface zones, the following application refers to the use of the second powder type with a diffused second inert plasticizer and the first powder type without a diffused second inert plasticizer.
Ordinarily, the lowest muzzle velocities and peak gas pressures occur at the lowest firing temperature and rise continuously with increasing firing temperature, i.e. the highest values
8 Date Recue/Date Received 2021-08-06 are normally achieved at the highest allowable firing temperature for a given powder type.
However, if the proper composition is selected, ambient temperature has only a minor effect on the characteristic internal ballistic data of muzzle velocity and peak gas pressure. The probability of a hit can be increased by selectively minimizing the range of variation of the muzzle velocities that occur over the entire allowable temperature range of the weapons system.
In addition, the increase in peak gas pressure on transition from 21 C to 63 C
is minimal. This opens up the possibility of operating the weapon under normal conditions, i.e.
at temperatures around 21 C, at a higher pressure level than is possible with conventional charge systems, because the only minor variation in the peak gas pressure on increasing firing temperature prevents this pressure from exceeding the maximum allowable gas pressure of the barrel of the howitzer used. This allows the performance of a howitzer system to be improved and opens up the possibility of increasing its range by using an additional charge.
Placement of a second inert plasticizer in the near-surface zones of the second powder type should preferably take place by means of corresponding surface treatment, for example by mixing a semi-finished product of the second powder type with a solution of the second inert plasticizer in an organic solvent. Accordingly, the following application also refers to powder types with and without surface treatment, wherein the powder type with surface treatment in the near-surface zones contains the second inert plasticizer in a concentration of 2 to 10 wt.%
and the powder type without surface treatment contains no second inert plasticizer in the near-surface zones. Both of the powder types contain as their main component nitrocellulose mixtures with a preferred average nitrogen content of above 13.25%. As further key components, the two powder types contain a crystalline energy carrier and at least one first inert plasticizer.
However, if the proper composition is selected, ambient temperature has only a minor effect on the characteristic internal ballistic data of muzzle velocity and peak gas pressure. The probability of a hit can be increased by selectively minimizing the range of variation of the muzzle velocities that occur over the entire allowable temperature range of the weapons system.
In addition, the increase in peak gas pressure on transition from 21 C to 63 C
is minimal. This opens up the possibility of operating the weapon under normal conditions, i.e.
at temperatures around 21 C, at a higher pressure level than is possible with conventional charge systems, because the only minor variation in the peak gas pressure on increasing firing temperature prevents this pressure from exceeding the maximum allowable gas pressure of the barrel of the howitzer used. This allows the performance of a howitzer system to be improved and opens up the possibility of increasing its range by using an additional charge.
Placement of a second inert plasticizer in the near-surface zones of the second powder type should preferably take place by means of corresponding surface treatment, for example by mixing a semi-finished product of the second powder type with a solution of the second inert plasticizer in an organic solvent. Accordingly, the following application also refers to powder types with and without surface treatment, wherein the powder type with surface treatment in the near-surface zones contains the second inert plasticizer in a concentration of 2 to 10 wt.%
and the powder type without surface treatment contains no second inert plasticizer in the near-surface zones. Both of the powder types contain as their main component nitrocellulose mixtures with a preferred average nitrogen content of above 13.25%. As further key components, the two powder types contain a crystalline energy carrier and at least one first inert plasticizer.
9 Furthermore, the powder types comprise at least one muzzle flash suppressor, such as e.g.
potassium sulfate, potassium bitartrate or potassium nitrate in amounts of 0.5-5 wt.%, preferably 1-3 wt.%. In addition, the propellants more preferably comprise stabilizers such as e.g. acardite II (CAS-4 724-18-5), centralite I (CAS-4: 90-93-7), diphenylamine (CAS-4: 122-39-4), or a barrel-protecting additive, such as e.g. calcium carbonate (CAS-4:
471-34-1).
Nitrocellulose is obtained by nitration of cellulose (cotton linters, pulp) and has been the most important starting material for the production of monobasic, dibasic, and tribasic propelling charges for over 100 years. Nitrocellulose is available in large quantities at inexpensive prices and is offered with a wide range of various physicochemical properties, such as nitrogen content, molecular weight and viscosity. These variations allow nitrocellulose to be processed into the widest variety of homogeneous propelling charge powder types. The energy content of nitrocellulose is adjusted via its nitrogen content.
Preferably, in an artillery shell, partial charges with the first powder type are used for the lower zones of the ballistic table, e.g. for charge 1, and partial charges with the second powder type are used for the upper zones of the ballistic table. This means that for firing an artillery shell, one to three, and preferably one to two partial charges with the first powder type are first charged into a casing, followed by one to six partial charges with the second powder type, depending on the zone of the ballistic table for which the artillery shell is to be used. By using a flexible number of partial charges, it becomes possible by means of the propelling charge .. system according to the invention to cover the widest possible range of zones of a ballistic table, wherein an outstandingly advantageous inner ballistic behavior can be achieved in all cases.
This is characterized in that with low charges, in which at least one partial charge with the first powder type is used, higher powder conversion rates (high thermal efficiencies) can be achieved, which minimizes the discharge of unburned powder material and increases the performance potential. In addition, the cold drop of the temperature curves of muzzle velocity and peak gas pressure is minimized.
On the other hand, the surface treatment of the second powder type of partial charges, which are used for high charges, causes the quotient of muzzle velocity and peak gas pressure (vo/pmax) to be as high as possible, i.e. the intended muzzle velocities required to meet the requirements of the ballistic table can be achieved with the lowest possible gas pressure. It was also surprisingly found that surface treatment of the second powder type significantly reduces the increase in the heat curves of muzzle velocity and peak gas pressure. In this manner, the muzzle velocity required for the highest zones of the ballistic table and thus the highest required muzzle velocity can be achieved without exceeding the gas pressure limits of the howitzer system used.
As initial tests have shown, the internal ballistic specifications could not be met if the charge system were composed of only one homogeneous powder type, e.g. in surface treatment with an average amount of the second inert plasticizer relative to the second powder type according to the invention. If only partial charges with the second powder type were used, conversion and ignition of the low charges would be poor, causing a large proportion of unburned powder to be discharged from the barrel. In addition, because of the poorer ignition time due to phlegmatization of the surface in the cold area in particular, significantly lower values and an unacceptable dispersion of muzzle velocity and peak gas pressure would be expected. On the other hand, if only partial charges with the first powder type were used, the peak gas pressure on firing of the highest charge for achieving the required muzzle velocity for maximum range would sharply increase at high firing temperatures and exceed the allowable pressure limits.
The first powder type and the second powder type preferably comprise particles with a circular cylindrical geometry and longitudinal channels running in an axial direction, wherein the particles of the first powder type preferably have one to four longitudinal channels and the particles of the second powder type have seven to nineteen longitudinal channels.
The longitudinal channels of the particles are arranged in an essentially circular area around the longitudinal axis of the particles. The particles have walls with a wall thickness between this area and the external circumferential surface of the particles.
Propellants composed of particles are used as pourable powder. They are capable of pouring (or trickling), which is important for the industrial filling of partial charges into containers, more particularly bags. The propelling charge powder can thus be handled like a liquid during filling into containers.
More particularly, the particles can be produced by extrusion.
The wall thicknesses of the two powder types depend on the artillery system in question. For a 105 mm system, the wall thickness of the first powder type is 0.4-1.2 mm, and preferably 0.5-1.0 mm, while the particles of the second powder type have thicknesses of 0.3-1.1 mm, and preferably 0.4-0.9 mm.
Within the meaning of the present application, the term "wall thickness" is understood to refer to the distance between the external circumferential surface of the particles and the area in which the longitudinal channels are arranged.
The concentration of the second inert plasticizer in the near-surface zones of the second powder type is preferably between 3 and 6 wt.%.
The at least one crystalline energy carrier is a nitramine compound of the general chemical structure RI -R2-N-NO2 and preferably comprises hexogen (RDX) or octogen (HMX), more particularly in a concentration of 0 to 30 wt.%, and most preferably 5 to 15 wt.%.
The energy carrier is preferably in crystalline form at room temperature. Use of these amounts in a base of nitrocellulose allows the average distances between the individual crystals of the crystalline energy carrier to be sufficiently large so that the individual crystals predominantly do not touch one another. As a result, on exposure to external mechanical stimuli, the shock pulse essentially cannot be passed on from one energy carrier crystal to the adjacent crystals.
A primary shock pulse is therefore not multiplied and transferred over the entire amount of powder.
The two compounds RDX and HMX of the general formula R-N-NO2 (R = residue) have a relatively small residue R, which constitutes a relatively small portion of the entire molecule compared to the nitramine structural element. The two compounds thus show a relatively high energy content.
RDX is preferably used as a crystalline energy carrier. Compared to HMX, it can be manufactured more economically and safely. HMX is more expensive than RDX but offers no particular advantages. Compared to RDX, other nitramine compounds (e.g. NIGU, etc.) have a relatively low internal ballistic performance potential.
Particularly preferably, the crystalline energy carrier has a specified average particle size. For example, RDX with an average particle size of 4-10 um, and more particularly 6 rim, is preferably used. It is important for the crystal energy carrier to have the most homogeneous and finest particulate size possible in order to improve particle burn-off and thus improve the internal ballistic performance potential.
As an alternative to the nitramine compounds, for example, a nitrate ester of the general formula R-O-NO would be conceivable. However, nitrate esters are less chemically stable than nitramine compounds. Moreover, it is possible to use nitramine-based crystalline energy carriers that have additional nitrate ester groups in their molecular structure. Examples of crystalline energy carriers include: hexanitroisowurtzitane (CL-20, CAS-4 14913-74-7), nitroguanidine (NIGU, NQ, CAS-# 70-25-7, N-methylnitramine (tetryl, N-Methyl-N,2,4,6-tetranitrobenzolamine, CAS-4 479-45-8) nitrotriazolone (NTO, CAS-4 932-64-9) and triaminotrinitrobenzene (TATB, CAS-4 3058-38-6). All of these energy carriers can be used either individually or in combination with one another.
Active substances knownper se, such as e.g. acardite II, can be used for stabilization.
Preferably, the propellants contain the at least one first inert plasticizer in a concentration of 0 to 10 wt.%, and preferably 1 to 5 wt.%, wherein the first inert plasticizer is preferably homogeneously distributed in the particle matrix.
By adding only relatively small amounts (e.g. <10 wt.%) of the at least one inert plasticizer to the particle matrix, resistance to mechanical stimuli can be significantly improved. Depending on the application, combinations of a plurality of inert plasticizers can be used in order to adjust the desired thermodynamic properties. The particle structure of such propellants can be adapted to the specific application (e.g. adaptation of burn-off characteristics to the barrel length, shell weight, etc. of the weapons system).
The at least one first plasticizer preferably comprises a carboxylic acid ester compound, more particularly from the groups of the phthalate esters, citrate esters, terephthalic esters, stearate esters or adipate esters.
The second inert plasticizer preferably comprises at least one compound from the group comprising camphor, dialkyl phthalate and dialkyl diphenylureas.
Particularly preferably, camphor (CAS-4 76-22-2) is used as the second inert plasticizer.
Each of the first and the second powder types of the at least two partial charges is preferably placed in a cylindrical cloth bag, wherein the cloth bags preferably have a through opening along their longitudinal axis.
The partial charges for artillery propelling charges of the prior art are filled into rectangular bags. Depending on the zone of the ballistic table to be covered with fire, a suitable number of these bags is arranged in a casing of an artillery shell. However, the drawback of said bags is that because of their rectangular configuration, they cannot be optimally placed inside the cylindrical casing of the shell, resulting in a relatively large amount of empty space inside the casing, which has an adverse effect on the maximum possible additional amount of powder that can be charged into the casing and can lead to irregular burn-off.
The use of cylindrical cloth bags according to the present invention allows more optimal space utilization inside a casing. This also prevents folding or rolling up of the bags prior to insertion, which considerably simplifies handling of the propelling charge system according to the invention.
If the cloth bags according to a preferred embodiment have a through opening along their longitudinal axis, this allows them to be slipped over and aligned onto an element centrally arranged inside the casing, such as e.g. a priming cap.
The diameter of the cylinder bottom surface of the cloth bags preferably corresponds to the internal diameter of a casing in which the propelling charge system according to the invention is to be placed. The height of the cylinder can be varied depending on the required amount of powder of the respective partial charge.
A person skilled in the art will recognize that the disclosed cloth bags can be used not only in connection with the propelling charge system according to the invention, but also generally used in various types of propelling charge systems.
Preferably, at least one of the at least two partial charges contains at least one piece of tin foil as a decoppering agent.
Compared to lead, which was previously conventionally used, tin has the advantage of being considerably more compatible with the environment and non-toxic.
In a preferred propelling charge system with seven partial charges, two pieces each of tin foil are preferably placed in several cloth bags.
The present application further relates to the use of a propelling charge system according to the invention for firing an artillery shell, wherein one to three partial charges with the first powder type is/are used in order to cover ranges in the lower zone of a ballistic table and an additional one to six partial charges with the second powder type is/are used in order to cover ranges in the upper zone of the ballistic table.
The following detailed description and the entirety of the patent claims disclose further advantageous embodiments and combinations of features of the invention.
Examples Preparation example 1: Powder type 1 without surface treatment, for zone 1 A 1-hole (longitudinal channel) powder is produced by processing 150 kg of powder paste composed of the solid components 10 wt.% of hexogen, 1.3 wt.% of acardite II, 1.2 wt.% of potassium sulfate, 1.5 wt.% of a phthalate ester (primarily composed of linear C9-C11 alcohols with an average molecular weight of 450 g/mol and an average dynamic viscosity at 20 C of 73 mPa*s) and nitrocellulose with a nitrogen content of 13.20 wt.% (made up to 100%), while adding diethyl ether and ethanol, into a solvent-wetted kneaded paste. After kneading for 70 min, this kneaded paste is pressed (i.e., extruded) through a die having a 1-hole geometry and a 3.2 mm strand cross-section. After predrying in air, the extruded strands are cut to the desired length. After this, the remaining residual solvents are removed at an elevated temperature. The resulting semifinished powder product is then heated to 55 C
and mixed in a copper polishing drum heated to 55 C with 0.1% graphite and 2.5 L of an aqueous ethanol solution. The reaction proceeds under constant rotation for 2 h, during which time the ethanol continuously evaporates. After completion of graphitization, the powder is placed in a bath for 22 h at 80 C, spread onto steel sheets and dried for 22 h at 60 C.
The resulting powder has the following physical properties: 2.00 mm external diameter, 5.04 mm length, 0.91 mm average wall thickness and 0.17 mm hole diameter, 3754 J/g heat content and 945 g/l bulk density.
Chemical stability:
Deflagration point = 174 C.
Heat flow calorimetry according to STANAG 4582 = 16.5 J/g resp. 20 p.W/g (requirement according to standard STANAG 4582: maximum heat generation < 114 [tW/g).
Preparation example 2: Powder type 2 with surface treatment, for zones 2-4 A 7-hole powder is produced by processing 225 kg of a powder paste composed of the solid components 16 wt.% of hexogen, 1.3 wt.% of acardite II, 1.2 wt.% of potassium sulfate, 1.5 wt.% of a phthalic acid ester (primarily composed of linear C9-C11 alcohols with an average molecular weight of 450 g/mol and an average dynamic viscosity at 20 C
of 73 mPa*s) and nitrocellulose with a nitrogen content of 13.20 wt.% (made up to 100%), while adding diethyl ether and ethanol, into a solvent-wetted kneaded paste. After kneading for 70 min, the kneaded paste is pressed (i.e., extruded) through a die having a 7-hole geometry and a 7.0 mm strand cross-section. After predrying in air, the extruded strands are cut to the desired length. After this, the remaining residual solvents are removed at an elevated temperature. The resulting semifinished powder product is then heated to 55 C and mixed in a copper polishing drum heated to 55 C with 0.12% graphite, 2.5% camphor and 4.5 L of an aqueous ethanol solution. The reaction proceeds under constant rotation for 2 h, during which time the ethanol continuously evaporates. After completion of the surface treatment, the powder is placed in a bath for 30 h at 85 C, spread onto steel sheets and dried for 22 h at 60 C.
The resulting powder has the following physical properties: 4.66 mm external diameter, 9.03 mm length, 1.05 mm average wall thickness and 0.15 mm hole diameter, 3653 J/g heat content and 957 g/1 bulk density.
Chemical stability:
Deflagration point = 176 C.
Heat flow calorimetry according to STANAG 4582 = 22.2 J/g resp. 27 W/g (requirement according to standard STANAG 4582: maximum heat generation < 114 uW/g).
Preparation example 3: Powder type 2 with surface treatment, for zones 5-6 A 7-hole powder is produced by processing 225 kg of a powder paste composed of the solid components 25 wt.% of hexogen, 1.3 wt.% of acardite II, 1.7 wt.% of potassium sulfate, 1.5 wt.% of a phthalic acid ester (primarily composed of linear C9-C11 alcohols with an average molecular weight of 450 g/mol and an average dynamic viscosity at 20 C
of 73 mPa*s) and nitrocellulose with a nitrogen content of 13.20 wt.% (made up to 100%), while adding diethyl ether and ethanol, into a solvent-wetted kneaded paste. After kneading for 70 min, the kneaded paste is pressed (i.e., extruded) through a die having a 7-hole geometry and an 8.0 mm strand cross-section. After predrying in air, the extruded strands are cut to the desired length. After this, the remaining residual solvents are removed at an elevated temperature. The resulting semifinished powder product is then heated to 55 C
and mixed in a copper polishing drum heated to 55 C with 0.12% graphite and 7.5 L of an aqueous ethanol solution. The reaction proceeds under constant rotation for 2 h, during which time the ethanol continuously evaporates. After completion of the surface treatment, the powder is placed in a bath for 30 h at 85 C, spread onto steel sheets and dried for 22 h at 60 C.
The resulting powder has the following physical properties: 5.66 mm external diameter, 8.59 mm length, 1.31 mm average wall thickness and 0.14 mm hole diameter, 3679 J/g heat content and 969 g/1 bulk density.
Chemical stability:
Deflagration point = 177 C.
Heat flow calorimetry according to STANAG 4582 = 25.1 J/g resp. 29 Wig (requirement according to standard STANAG 4582: maximum heat generation < 114 W/g).
Application example 1:
System: Howitzer system 105 mm M119 Projectile: M1 with a mass of 14.5 kg Charge bag: Donut-Bag NCW with central hole Primer: M28E2 (Benite primer) Table 1: Charge masses of powder used for zones 1-6 Zone Powder Surface treatment Charge mass 1 Preparation example 1 No 196 9 2 Preparation example 2 Yes 116 3 Preparation example 2 Yes 219 9 4 Preparation example 2 Yes 265 g 5 Preparation example 3 Yes 6259 6 Preparation example 3 Yes 640 g Table 2: Muzzle velocities in m/s at -46 C, 21 C and 63 C
Zone -46 C 21 C 63 C
1 177.1 183.0 2 215.5 224.1 3 - 277.2 4 340.3 358.2 374.0 472.8 504.0 494.7 6 651.5 651.8 6208.
Table 3: Peak gas pressures in bar at -46 C, 21 C and 63 C
Zone -46 C 21 C 63 C
5 Table 4: Thermal efficiencies for energy conversion of the individual zones at 21 C
Zone Therm. efficiency 1 33%
2 32%
3 29 %
4 32%
5 35 %
41%
It can be seen that by means of the novel charge, composed of the combination according to the invention of two powder types with and without surface treatment, i.e.
with a diffused second inert plasticizer and without a diffused second inert plasticizer for low charges 1-2 in the cold area, only extremely small decreases in muzzle velocity occur, specifically - 5.9 m/s in zone 1 and 8.6 m/s in zone 2. The energy conversion into kinetic energy takes place with a high degree of efficiency both in zone 1, where only the powder without surface treatment is used, and in zone 2, where the combination of the two powder types with and without surface treatment is used, which is reflected in high efficiencies of 33% (zone 1) and 32% (zone 2) despite the low peak gas pressures of < 500 bar.
In the case of the higher charges for zones 4-6 as well, the combination according to the invention of two powder types with and without surface treatment astonishingly makes it possible for the cold drops of the muzzle velocities to be only relatively small, specifically between 20-30 m/s for zones 4 and 5, while surprisingly, there is virtually no cold drop in zone 6, i.e. the peak gas pressures at -46 C and 21 C are virtually identical.
This shows that in the charge system described, because of the combination of two powder types with and without surface treatment, the muzzle velocities of the individual partial charges on firing within the temperature range of -46 C to 21 C are only affected to a minor degree by the ambient temperature, thus significantly increasing the hit probability.
For zone 6, the amount of powder was adjusted such that at 21 C, the muzzle velocity was 652 m/s. The peak gas pressure occurring at this velocity is only 3371 bar, i.e.
the ratio vo/pmax is relatively high, as hoped. In addition, no increase in pressure occurs on transition to the maximum firing temperature. This means that because of the charge structure according to the invention, the weapon can be operated over the entire temperature range far below the system pressure limits of 3965 bar. If needed in order to improve performance, the pressure reserve of 600 bar can be utilized by means of an additional charge for increased range.
In use of a conventional charge system having powder without surface treatment, a classic burn-off occurs, i.e. a continuous increase in muzzle velocity and peak gas pressure with increasing firing temperature. The result of this behavior is that at the maximum allowable firing temperature, one reaches the gas pressure limits, thus eliminating the possibility of increasing the range. If the increase in pressure is extremely high with a conventional charging design in a particular application, it may happen that the peak gas pressure at 63 C is even exceeded on reaching the muzzle velocity required at 21 C, i.e. the weapon can then be operated only over a limited temperature range.
Brief description of the drawings The drawings used to explain the example show the following:
Fig. 1 a propelling charge system according to the invention with seven partial charges in cloth bags;
Fig. 2 an arrangement of the propelling charge systems in a casing of an artillery shell.
As a rule, the same parts are designated by the same reference numbers in the figures.
Embodiments of the invention Fig. 1 shows a propelling charge system according to the invention 1 with six partial charges 2.1, 3.1-3.5. Each of the partial charges 2.1, 3.1-3.5 is placed in an essentially cylindrical cloth bag. The propelling charge system 1 shown comprises five second partial charges 3.1-3.5 with a second powder type as a propellant, containing between 2 and 10 wt.% of a second inert plasticizer in the region of the near-surface zones to a penetration depth of at most 400 mn.
The propelling charge system 1 further comprises a first partial charge 2.1 with a first powder type as a propellant, which contains no second inert plasticizer in the near-surface zones. The first partial charge 2.1 serves to cover the lower zone of the ballistic table, while the second partial charges 3.1-3.5 can be used to cover the upper zones of the ballistic table.
Fig. 2 shows the arrangement of the propelling charge system according to the invention 1 in a casing 4 of an artillery shell. In this case, the first partial charge 2.1 is arranged below the second partial charge 3.1-3.5 in the casing 4. The cloth bags of the partial charges 2.1, 3.1-3.4 have a through opening 5 along their longitudinal axis, through which a priming cap 6 (shown by the broken line) is guided. Because of their cylindrical shape, these cloth bags can be placed inside the casing 4 in a highly simple and space-saving manner.
potassium sulfate, potassium bitartrate or potassium nitrate in amounts of 0.5-5 wt.%, preferably 1-3 wt.%. In addition, the propellants more preferably comprise stabilizers such as e.g. acardite II (CAS-4 724-18-5), centralite I (CAS-4: 90-93-7), diphenylamine (CAS-4: 122-39-4), or a barrel-protecting additive, such as e.g. calcium carbonate (CAS-4:
471-34-1).
Nitrocellulose is obtained by nitration of cellulose (cotton linters, pulp) and has been the most important starting material for the production of monobasic, dibasic, and tribasic propelling charges for over 100 years. Nitrocellulose is available in large quantities at inexpensive prices and is offered with a wide range of various physicochemical properties, such as nitrogen content, molecular weight and viscosity. These variations allow nitrocellulose to be processed into the widest variety of homogeneous propelling charge powder types. The energy content of nitrocellulose is adjusted via its nitrogen content.
Preferably, in an artillery shell, partial charges with the first powder type are used for the lower zones of the ballistic table, e.g. for charge 1, and partial charges with the second powder type are used for the upper zones of the ballistic table. This means that for firing an artillery shell, one to three, and preferably one to two partial charges with the first powder type are first charged into a casing, followed by one to six partial charges with the second powder type, depending on the zone of the ballistic table for which the artillery shell is to be used. By using a flexible number of partial charges, it becomes possible by means of the propelling charge .. system according to the invention to cover the widest possible range of zones of a ballistic table, wherein an outstandingly advantageous inner ballistic behavior can be achieved in all cases.
This is characterized in that with low charges, in which at least one partial charge with the first powder type is used, higher powder conversion rates (high thermal efficiencies) can be achieved, which minimizes the discharge of unburned powder material and increases the performance potential. In addition, the cold drop of the temperature curves of muzzle velocity and peak gas pressure is minimized.
On the other hand, the surface treatment of the second powder type of partial charges, which are used for high charges, causes the quotient of muzzle velocity and peak gas pressure (vo/pmax) to be as high as possible, i.e. the intended muzzle velocities required to meet the requirements of the ballistic table can be achieved with the lowest possible gas pressure. It was also surprisingly found that surface treatment of the second powder type significantly reduces the increase in the heat curves of muzzle velocity and peak gas pressure. In this manner, the muzzle velocity required for the highest zones of the ballistic table and thus the highest required muzzle velocity can be achieved without exceeding the gas pressure limits of the howitzer system used.
As initial tests have shown, the internal ballistic specifications could not be met if the charge system were composed of only one homogeneous powder type, e.g. in surface treatment with an average amount of the second inert plasticizer relative to the second powder type according to the invention. If only partial charges with the second powder type were used, conversion and ignition of the low charges would be poor, causing a large proportion of unburned powder to be discharged from the barrel. In addition, because of the poorer ignition time due to phlegmatization of the surface in the cold area in particular, significantly lower values and an unacceptable dispersion of muzzle velocity and peak gas pressure would be expected. On the other hand, if only partial charges with the first powder type were used, the peak gas pressure on firing of the highest charge for achieving the required muzzle velocity for maximum range would sharply increase at high firing temperatures and exceed the allowable pressure limits.
The first powder type and the second powder type preferably comprise particles with a circular cylindrical geometry and longitudinal channels running in an axial direction, wherein the particles of the first powder type preferably have one to four longitudinal channels and the particles of the second powder type have seven to nineteen longitudinal channels.
The longitudinal channels of the particles are arranged in an essentially circular area around the longitudinal axis of the particles. The particles have walls with a wall thickness between this area and the external circumferential surface of the particles.
Propellants composed of particles are used as pourable powder. They are capable of pouring (or trickling), which is important for the industrial filling of partial charges into containers, more particularly bags. The propelling charge powder can thus be handled like a liquid during filling into containers.
More particularly, the particles can be produced by extrusion.
The wall thicknesses of the two powder types depend on the artillery system in question. For a 105 mm system, the wall thickness of the first powder type is 0.4-1.2 mm, and preferably 0.5-1.0 mm, while the particles of the second powder type have thicknesses of 0.3-1.1 mm, and preferably 0.4-0.9 mm.
Within the meaning of the present application, the term "wall thickness" is understood to refer to the distance between the external circumferential surface of the particles and the area in which the longitudinal channels are arranged.
The concentration of the second inert plasticizer in the near-surface zones of the second powder type is preferably between 3 and 6 wt.%.
The at least one crystalline energy carrier is a nitramine compound of the general chemical structure RI -R2-N-NO2 and preferably comprises hexogen (RDX) or octogen (HMX), more particularly in a concentration of 0 to 30 wt.%, and most preferably 5 to 15 wt.%.
The energy carrier is preferably in crystalline form at room temperature. Use of these amounts in a base of nitrocellulose allows the average distances between the individual crystals of the crystalline energy carrier to be sufficiently large so that the individual crystals predominantly do not touch one another. As a result, on exposure to external mechanical stimuli, the shock pulse essentially cannot be passed on from one energy carrier crystal to the adjacent crystals.
A primary shock pulse is therefore not multiplied and transferred over the entire amount of powder.
The two compounds RDX and HMX of the general formula R-N-NO2 (R = residue) have a relatively small residue R, which constitutes a relatively small portion of the entire molecule compared to the nitramine structural element. The two compounds thus show a relatively high energy content.
RDX is preferably used as a crystalline energy carrier. Compared to HMX, it can be manufactured more economically and safely. HMX is more expensive than RDX but offers no particular advantages. Compared to RDX, other nitramine compounds (e.g. NIGU, etc.) have a relatively low internal ballistic performance potential.
Particularly preferably, the crystalline energy carrier has a specified average particle size. For example, RDX with an average particle size of 4-10 um, and more particularly 6 rim, is preferably used. It is important for the crystal energy carrier to have the most homogeneous and finest particulate size possible in order to improve particle burn-off and thus improve the internal ballistic performance potential.
As an alternative to the nitramine compounds, for example, a nitrate ester of the general formula R-O-NO would be conceivable. However, nitrate esters are less chemically stable than nitramine compounds. Moreover, it is possible to use nitramine-based crystalline energy carriers that have additional nitrate ester groups in their molecular structure. Examples of crystalline energy carriers include: hexanitroisowurtzitane (CL-20, CAS-4 14913-74-7), nitroguanidine (NIGU, NQ, CAS-# 70-25-7, N-methylnitramine (tetryl, N-Methyl-N,2,4,6-tetranitrobenzolamine, CAS-4 479-45-8) nitrotriazolone (NTO, CAS-4 932-64-9) and triaminotrinitrobenzene (TATB, CAS-4 3058-38-6). All of these energy carriers can be used either individually or in combination with one another.
Active substances knownper se, such as e.g. acardite II, can be used for stabilization.
Preferably, the propellants contain the at least one first inert plasticizer in a concentration of 0 to 10 wt.%, and preferably 1 to 5 wt.%, wherein the first inert plasticizer is preferably homogeneously distributed in the particle matrix.
By adding only relatively small amounts (e.g. <10 wt.%) of the at least one inert plasticizer to the particle matrix, resistance to mechanical stimuli can be significantly improved. Depending on the application, combinations of a plurality of inert plasticizers can be used in order to adjust the desired thermodynamic properties. The particle structure of such propellants can be adapted to the specific application (e.g. adaptation of burn-off characteristics to the barrel length, shell weight, etc. of the weapons system).
The at least one first plasticizer preferably comprises a carboxylic acid ester compound, more particularly from the groups of the phthalate esters, citrate esters, terephthalic esters, stearate esters or adipate esters.
The second inert plasticizer preferably comprises at least one compound from the group comprising camphor, dialkyl phthalate and dialkyl diphenylureas.
Particularly preferably, camphor (CAS-4 76-22-2) is used as the second inert plasticizer.
Each of the first and the second powder types of the at least two partial charges is preferably placed in a cylindrical cloth bag, wherein the cloth bags preferably have a through opening along their longitudinal axis.
The partial charges for artillery propelling charges of the prior art are filled into rectangular bags. Depending on the zone of the ballistic table to be covered with fire, a suitable number of these bags is arranged in a casing of an artillery shell. However, the drawback of said bags is that because of their rectangular configuration, they cannot be optimally placed inside the cylindrical casing of the shell, resulting in a relatively large amount of empty space inside the casing, which has an adverse effect on the maximum possible additional amount of powder that can be charged into the casing and can lead to irregular burn-off.
The use of cylindrical cloth bags according to the present invention allows more optimal space utilization inside a casing. This also prevents folding or rolling up of the bags prior to insertion, which considerably simplifies handling of the propelling charge system according to the invention.
If the cloth bags according to a preferred embodiment have a through opening along their longitudinal axis, this allows them to be slipped over and aligned onto an element centrally arranged inside the casing, such as e.g. a priming cap.
The diameter of the cylinder bottom surface of the cloth bags preferably corresponds to the internal diameter of a casing in which the propelling charge system according to the invention is to be placed. The height of the cylinder can be varied depending on the required amount of powder of the respective partial charge.
A person skilled in the art will recognize that the disclosed cloth bags can be used not only in connection with the propelling charge system according to the invention, but also generally used in various types of propelling charge systems.
Preferably, at least one of the at least two partial charges contains at least one piece of tin foil as a decoppering agent.
Compared to lead, which was previously conventionally used, tin has the advantage of being considerably more compatible with the environment and non-toxic.
In a preferred propelling charge system with seven partial charges, two pieces each of tin foil are preferably placed in several cloth bags.
The present application further relates to the use of a propelling charge system according to the invention for firing an artillery shell, wherein one to three partial charges with the first powder type is/are used in order to cover ranges in the lower zone of a ballistic table and an additional one to six partial charges with the second powder type is/are used in order to cover ranges in the upper zone of the ballistic table.
The following detailed description and the entirety of the patent claims disclose further advantageous embodiments and combinations of features of the invention.
Examples Preparation example 1: Powder type 1 without surface treatment, for zone 1 A 1-hole (longitudinal channel) powder is produced by processing 150 kg of powder paste composed of the solid components 10 wt.% of hexogen, 1.3 wt.% of acardite II, 1.2 wt.% of potassium sulfate, 1.5 wt.% of a phthalate ester (primarily composed of linear C9-C11 alcohols with an average molecular weight of 450 g/mol and an average dynamic viscosity at 20 C of 73 mPa*s) and nitrocellulose with a nitrogen content of 13.20 wt.% (made up to 100%), while adding diethyl ether and ethanol, into a solvent-wetted kneaded paste. After kneading for 70 min, this kneaded paste is pressed (i.e., extruded) through a die having a 1-hole geometry and a 3.2 mm strand cross-section. After predrying in air, the extruded strands are cut to the desired length. After this, the remaining residual solvents are removed at an elevated temperature. The resulting semifinished powder product is then heated to 55 C
and mixed in a copper polishing drum heated to 55 C with 0.1% graphite and 2.5 L of an aqueous ethanol solution. The reaction proceeds under constant rotation for 2 h, during which time the ethanol continuously evaporates. After completion of graphitization, the powder is placed in a bath for 22 h at 80 C, spread onto steel sheets and dried for 22 h at 60 C.
The resulting powder has the following physical properties: 2.00 mm external diameter, 5.04 mm length, 0.91 mm average wall thickness and 0.17 mm hole diameter, 3754 J/g heat content and 945 g/l bulk density.
Chemical stability:
Deflagration point = 174 C.
Heat flow calorimetry according to STANAG 4582 = 16.5 J/g resp. 20 p.W/g (requirement according to standard STANAG 4582: maximum heat generation < 114 [tW/g).
Preparation example 2: Powder type 2 with surface treatment, for zones 2-4 A 7-hole powder is produced by processing 225 kg of a powder paste composed of the solid components 16 wt.% of hexogen, 1.3 wt.% of acardite II, 1.2 wt.% of potassium sulfate, 1.5 wt.% of a phthalic acid ester (primarily composed of linear C9-C11 alcohols with an average molecular weight of 450 g/mol and an average dynamic viscosity at 20 C
of 73 mPa*s) and nitrocellulose with a nitrogen content of 13.20 wt.% (made up to 100%), while adding diethyl ether and ethanol, into a solvent-wetted kneaded paste. After kneading for 70 min, the kneaded paste is pressed (i.e., extruded) through a die having a 7-hole geometry and a 7.0 mm strand cross-section. After predrying in air, the extruded strands are cut to the desired length. After this, the remaining residual solvents are removed at an elevated temperature. The resulting semifinished powder product is then heated to 55 C and mixed in a copper polishing drum heated to 55 C with 0.12% graphite, 2.5% camphor and 4.5 L of an aqueous ethanol solution. The reaction proceeds under constant rotation for 2 h, during which time the ethanol continuously evaporates. After completion of the surface treatment, the powder is placed in a bath for 30 h at 85 C, spread onto steel sheets and dried for 22 h at 60 C.
The resulting powder has the following physical properties: 4.66 mm external diameter, 9.03 mm length, 1.05 mm average wall thickness and 0.15 mm hole diameter, 3653 J/g heat content and 957 g/1 bulk density.
Chemical stability:
Deflagration point = 176 C.
Heat flow calorimetry according to STANAG 4582 = 22.2 J/g resp. 27 W/g (requirement according to standard STANAG 4582: maximum heat generation < 114 uW/g).
Preparation example 3: Powder type 2 with surface treatment, for zones 5-6 A 7-hole powder is produced by processing 225 kg of a powder paste composed of the solid components 25 wt.% of hexogen, 1.3 wt.% of acardite II, 1.7 wt.% of potassium sulfate, 1.5 wt.% of a phthalic acid ester (primarily composed of linear C9-C11 alcohols with an average molecular weight of 450 g/mol and an average dynamic viscosity at 20 C
of 73 mPa*s) and nitrocellulose with a nitrogen content of 13.20 wt.% (made up to 100%), while adding diethyl ether and ethanol, into a solvent-wetted kneaded paste. After kneading for 70 min, the kneaded paste is pressed (i.e., extruded) through a die having a 7-hole geometry and an 8.0 mm strand cross-section. After predrying in air, the extruded strands are cut to the desired length. After this, the remaining residual solvents are removed at an elevated temperature. The resulting semifinished powder product is then heated to 55 C
and mixed in a copper polishing drum heated to 55 C with 0.12% graphite and 7.5 L of an aqueous ethanol solution. The reaction proceeds under constant rotation for 2 h, during which time the ethanol continuously evaporates. After completion of the surface treatment, the powder is placed in a bath for 30 h at 85 C, spread onto steel sheets and dried for 22 h at 60 C.
The resulting powder has the following physical properties: 5.66 mm external diameter, 8.59 mm length, 1.31 mm average wall thickness and 0.14 mm hole diameter, 3679 J/g heat content and 969 g/1 bulk density.
Chemical stability:
Deflagration point = 177 C.
Heat flow calorimetry according to STANAG 4582 = 25.1 J/g resp. 29 Wig (requirement according to standard STANAG 4582: maximum heat generation < 114 W/g).
Application example 1:
System: Howitzer system 105 mm M119 Projectile: M1 with a mass of 14.5 kg Charge bag: Donut-Bag NCW with central hole Primer: M28E2 (Benite primer) Table 1: Charge masses of powder used for zones 1-6 Zone Powder Surface treatment Charge mass 1 Preparation example 1 No 196 9 2 Preparation example 2 Yes 116 3 Preparation example 2 Yes 219 9 4 Preparation example 2 Yes 265 g 5 Preparation example 3 Yes 6259 6 Preparation example 3 Yes 640 g Table 2: Muzzle velocities in m/s at -46 C, 21 C and 63 C
Zone -46 C 21 C 63 C
1 177.1 183.0 2 215.5 224.1 3 - 277.2 4 340.3 358.2 374.0 472.8 504.0 494.7 6 651.5 651.8 6208.
Table 3: Peak gas pressures in bar at -46 C, 21 C and 63 C
Zone -46 C 21 C 63 C
5 Table 4: Thermal efficiencies for energy conversion of the individual zones at 21 C
Zone Therm. efficiency 1 33%
2 32%
3 29 %
4 32%
5 35 %
41%
It can be seen that by means of the novel charge, composed of the combination according to the invention of two powder types with and without surface treatment, i.e.
with a diffused second inert plasticizer and without a diffused second inert plasticizer for low charges 1-2 in the cold area, only extremely small decreases in muzzle velocity occur, specifically - 5.9 m/s in zone 1 and 8.6 m/s in zone 2. The energy conversion into kinetic energy takes place with a high degree of efficiency both in zone 1, where only the powder without surface treatment is used, and in zone 2, where the combination of the two powder types with and without surface treatment is used, which is reflected in high efficiencies of 33% (zone 1) and 32% (zone 2) despite the low peak gas pressures of < 500 bar.
In the case of the higher charges for zones 4-6 as well, the combination according to the invention of two powder types with and without surface treatment astonishingly makes it possible for the cold drops of the muzzle velocities to be only relatively small, specifically between 20-30 m/s for zones 4 and 5, while surprisingly, there is virtually no cold drop in zone 6, i.e. the peak gas pressures at -46 C and 21 C are virtually identical.
This shows that in the charge system described, because of the combination of two powder types with and without surface treatment, the muzzle velocities of the individual partial charges on firing within the temperature range of -46 C to 21 C are only affected to a minor degree by the ambient temperature, thus significantly increasing the hit probability.
For zone 6, the amount of powder was adjusted such that at 21 C, the muzzle velocity was 652 m/s. The peak gas pressure occurring at this velocity is only 3371 bar, i.e.
the ratio vo/pmax is relatively high, as hoped. In addition, no increase in pressure occurs on transition to the maximum firing temperature. This means that because of the charge structure according to the invention, the weapon can be operated over the entire temperature range far below the system pressure limits of 3965 bar. If needed in order to improve performance, the pressure reserve of 600 bar can be utilized by means of an additional charge for increased range.
In use of a conventional charge system having powder without surface treatment, a classic burn-off occurs, i.e. a continuous increase in muzzle velocity and peak gas pressure with increasing firing temperature. The result of this behavior is that at the maximum allowable firing temperature, one reaches the gas pressure limits, thus eliminating the possibility of increasing the range. If the increase in pressure is extremely high with a conventional charging design in a particular application, it may happen that the peak gas pressure at 63 C is even exceeded on reaching the muzzle velocity required at 21 C, i.e. the weapon can then be operated only over a limited temperature range.
Brief description of the drawings The drawings used to explain the example show the following:
Fig. 1 a propelling charge system according to the invention with seven partial charges in cloth bags;
Fig. 2 an arrangement of the propelling charge systems in a casing of an artillery shell.
As a rule, the same parts are designated by the same reference numbers in the figures.
Embodiments of the invention Fig. 1 shows a propelling charge system according to the invention 1 with six partial charges 2.1, 3.1-3.5. Each of the partial charges 2.1, 3.1-3.5 is placed in an essentially cylindrical cloth bag. The propelling charge system 1 shown comprises five second partial charges 3.1-3.5 with a second powder type as a propellant, containing between 2 and 10 wt.% of a second inert plasticizer in the region of the near-surface zones to a penetration depth of at most 400 mn.
The propelling charge system 1 further comprises a first partial charge 2.1 with a first powder type as a propellant, which contains no second inert plasticizer in the near-surface zones. The first partial charge 2.1 serves to cover the lower zone of the ballistic table, while the second partial charges 3.1-3.5 can be used to cover the upper zones of the ballistic table.
Fig. 2 shows the arrangement of the propelling charge system according to the invention 1 in a casing 4 of an artillery shell. In this case, the first partial charge 2.1 is arranged below the second partial charge 3.1-3.5 in the casing 4. The cloth bags of the partial charges 2.1, 3.1-3.4 have a through opening 5 along their longitudinal axis, through which a priming cap 6 (shown by the broken line) is guided. Because of their cylindrical shape, these cloth bags can be placed inside the casing 4 in a highly simple and space-saving manner.
Claims (11)
1. Propelling charge system for firing artillery shells with at least two partial charges, wherein each of the partial charges has one powder type as a propellant, said powder type comprising nitrocellulose, at least one crystalline energy carrier and at least one first inert plasticizer, wherein at least one partial charge comprises a first powder type and the at least one further partial charge comprises a second powder type, wherein the second powder type contains 2 to 10 wt% of a second inert plasticizer in the region of the near-surface zones to a penetration depth of at most 400 p.m and the first powder type contains no second inert plasticizer in the near-surface zones.
2. Propelling charge system according to Claim 1, characterized in that the first and the second powder type comprise particles having a circular cylindrical geometry with longitudinal channels running in an axial direction,.
3. Propelling charge system according to Claim 2, characterized in that the particles of the first powder type have a wall thickness of 0.4-1.2 mm and the particles of the second powder type have a wall thickness of 0.3-1.1 mm.
4. Propelling charge system according to Claim 1, characterized in that the concentration of the second inert plasticizer in the near-surface zones of the second powder type is between 3 and 6 wt.%.
5. Propelling charge system according to Claim 1, characterized in that the at least one crystalline energy carrier comprises a nitramine compound in a concentration of 5 to 15 wt.%.
Date Recue/Date Received 2021-08-06
Date Recue/Date Received 2021-08-06
6. Propelling charge system according to Claim 1, characterized in that the first and the second powder type comprise the at least one first inert plasticizer in a concentration of 1 to 5 wt.%.
7. Propelling charge system according to Claim 1, characterized in that the at least one first plasticizer comprises a carboxylic acid ester compound.
8. Propelling charge system according to Claim 1, characterized in that the second inert plasticizer is at least one compound from the group comprising camphor, dialkyl phthalate and dialkyl diphenylureas.
9. Propelling charge system according to Claim 1, characterized in that each of the at least two partial charges is contained in a cylindrical cloth bag.
10. Propelling charge system according Claim 1, characterized in that at least one of the at least two partial charges contains at least one piece of tin foil as a decoppering agent.
11. Use of a propelling charge system according to Claim 1 for firing an artillery shell, wherein one to three partial charges with the first powder type is/are used in order to cover ranges in the lower zone of a ballistic table, and additional partial charges.
Date Recue/Date Received 2021-08-06
Date Recue/Date Received 2021-08-06
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CH2015/000097 WO2017004726A1 (en) | 2015-07-03 | 2015-07-03 | Propellant charge system for artillery shells |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2990862A1 CA2990862A1 (en) | 2017-01-12 |
| CA2990862C true CA2990862C (en) | 2022-05-31 |
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ID=53716266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2990862A Active CA2990862C (en) | 2015-07-03 | 2015-07-03 | Propelling charge system for artillery shells |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP3317606B1 (en) |
| KR (1) | KR20180055762A (en) |
| CA (1) | CA2990862C (en) |
| WO (1) | WO2017004726A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2555618B (en) * | 2016-11-04 | 2021-12-29 | Bae Systems Plc | Munition charge container |
| GB2555616B (en) | 2016-11-04 | 2021-10-06 | Bae Systems Plc | Modular charge container |
| KR102561531B1 (en) * | 2023-02-02 | 2023-07-28 | 최은영 | A propelling charge having a copper removal function of gun barrel steel wire |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5747723A (en) * | 1996-11-26 | 1998-05-05 | The United States Of America As Represented By The Secretary Of The Army | Modular artillery charge system |
| DE50009362D1 (en) | 2000-06-15 | 2005-03-03 | Nitrochemie Wimmis Ag Wimmis | Process for the production of a functional high-energy material |
| US6666141B2 (en) * | 2001-07-09 | 2003-12-23 | United Defense, L.P. | Variable increment modular artillery propellant |
| SE523997C2 (en) * | 2002-02-08 | 2004-06-15 | Nexplo Bofors Ab | decoppering |
| EP1857429B1 (en) | 2006-05-19 | 2013-03-27 | Nitrochemie Wimmis AG | Propulsive means for accelerating projectiles |
| CA2845852A1 (en) * | 2011-09-15 | 2011-12-15 | Nitrochemie Wimmis Ag | Nitroglycerine-free multi-perforated high-performing propellant system |
| US20150321969A1 (en) | 2013-01-29 | 2015-11-12 | Nitrochemie Wimmis Ag | Powder for accelerating projectiles for mortar systems |
-
2015
- 2015-07-03 CA CA2990862A patent/CA2990862C/en active Active
- 2015-07-03 KR KR1020177037859A patent/KR20180055762A/en not_active Application Discontinuation
- 2015-07-03 EP EP15739498.2A patent/EP3317606B1/en active Active
- 2015-07-03 WO PCT/CH2015/000097 patent/WO2017004726A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| EP3317606A1 (en) | 2018-05-09 |
| WO2017004726A1 (en) | 2017-01-12 |
| CA2990862A1 (en) | 2017-01-12 |
| KR20180055762A (en) | 2018-05-25 |
| EP3317606B1 (en) | 2020-06-10 |
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