Cutaway model of a 155mm DPICM ERFB with BB (Dual Purpose Improved Conventional Munitions, Extended Range Full Bore with Base Bleed) projectile, most probably of an experimental design. The projectile is meant as a long range projectile. Comparable ERFB projectiles with a base bleed (HE) have a range of 41 kilometers.
I do not know the official type designation of the projectile.
The shape of the projectile (ERFB with BB) can be traced back to the HARP project of professor Gerald Bull: an attempt to shoot a projectile into space. These projectiles were superslim of shape and has three notches on the side to prevent the projectile from tumbling in the barrel upon firing due to lack of barrel contact guidance.
Google for: Gerald Bull, Harp project, project Babylon for more info.
Purpose of the projectile:
The purpose of this projectile is to saturate an area with (M42/46) submunitions (also called bomblets), thereby creating a more controlled fragmentation over a larger area -when compared to the 155 mm M107 HE (DM21) projectile-, together with an armour piercing effect caused by the shaped charge.
The projectile is meant to be used against uncovered personel, artillery positions, resupply points, and against lightly armoured vehicles. It is not meant as a replacement for the M107 HE, but as a supplement.
The M42/46 bomblet will not knock out a main battle tank, but can severely damage parts like optics, the main weapon and other external parts of the tank, thereby effectively crippling the tank.
Description of projectile:
The body of the projectile is a steel -drawn and rolled- tube, threaded in top to receive the aluminium upper piece which is screwed into the body. The body is machined on the inside and three keyways -at 120 degrees each- are machined into the longitudal direction of the lower body. In the top of the lower body, the diameter becomes smaller to form the seat for a piston.The part above the piston, together with the aluminium upper cap forms the combustion chamber of the projectile.
The piston is build up of an aluminium flange placed on a steel flange which closely fits the inside of the lower projectile body. The steel part of the pistonhas an O-ring on the outer rim to enshure a gas tight sealing between inner body and the piston.
The lower part of the body has five windings of fine thread to receive the aluminium basecap containing the basebleed, which has only four winding of thread. A rubber O-ring and a paste/glue between the thread enshure a gas tight seal beween body and basecap while travelling through the barrel.
An aluminium hat with four longitudal weakenings at 90 degrees each containing the expelling charge is placed in the top of the upper (aluminium) piece. The upper rim of the hat is rolled outward to lock it into the upper piece. The powder for the expelling charge M10 powder and it is packed in a nylon bag. On top of this aluminium hat a steel filler disc is placed, locking up the powder charge. Screwing the fuze on the projectile locks up the ring.
Functioning of the projectile:
Before firing, the fuze is set on airburst on a point at approximately 300 mtrs above the ground.
When the time fuze ignites on the set time, the flame enters the detonator in the centrifugal safety element. The flame of the detonator ignites the powder of the expelling charge. The gasses rip open the aluminium hat over the four longitudal weakenings, filling the combustion chamber and starting to press upon the piston, up to a moment where the four windings of thread are ripped away and the cargo of 88 M42/M46 submunitions are dispersed (centrifugal force) from the base of the projectile. Depending upon the trajectory angle and speed, a round or an elipse shaped impact pattern of submunitions will occur.
Submunition M42 / M46, description and functioning:
The cargo of this projectile is made of 56 M42/M46 HEAT Frag (High Explosive Anti Tank Fragmentation)submunitions, placed in 7 columns of 8pcs. Six columns in a circular pattern around one column in the center. The submunitions are placed cone forward, the impact fuze M233 of the submunition stored in the cone of the submunition below. On the outer circumference of the submunitions the space between the submunitions and the inner wall of the projectile is filled with triangular nylon filler pieces, tightly locking up the submunitions. Three of these outer rows of filler pieces (at 120 degr. each) are made of aluminium and have a key on the outside that fits into the three keyways in the inside of the body, preventing the cargo of submunitions from radial movement compared to the projectile body on firing.
With regards, DJH
I do not know the official type designation of the projectile.
The shape of the projectile (ERFB with BB) can be traced back to the HARP project of professor Gerald Bull: an attempt to shoot a projectile into space. These projectiles were superslim of shape and has three notches on the side to prevent the projectile from tumbling in the barrel upon firing due to lack of barrel contact guidance.
Google for: Gerald Bull, Harp project, project Babylon for more info.
Purpose of the projectile:
The purpose of this projectile is to saturate an area with (M42/46) submunitions (also called bomblets), thereby creating a more controlled fragmentation over a larger area -when compared to the 155 mm M107 HE (DM21) projectile-, together with an armour piercing effect caused by the shaped charge.
The projectile is meant to be used against uncovered personel, artillery positions, resupply points, and against lightly armoured vehicles. It is not meant as a replacement for the M107 HE, but as a supplement.
The M42/46 bomblet will not knock out a main battle tank, but can severely damage parts like optics, the main weapon and other external parts of the tank, thereby effectively crippling the tank.
Description of projectile:
The body of the projectile is a steel -drawn and rolled- tube, threaded in top to receive the aluminium upper piece which is screwed into the body. The body is machined on the inside and three keyways -at 120 degrees each- are machined into the longitudal direction of the lower body. In the top of the lower body, the diameter becomes smaller to form the seat for a piston.The part above the piston, together with the aluminium upper cap forms the combustion chamber of the projectile.
The piston is build up of an aluminium flange placed on a steel flange which closely fits the inside of the lower projectile body. The steel part of the pistonhas an O-ring on the outer rim to enshure a gas tight sealing between inner body and the piston.
The lower part of the body has five windings of fine thread to receive the aluminium basecap containing the basebleed, which has only four winding of thread. A rubber O-ring and a paste/glue between the thread enshure a gas tight seal beween body and basecap while travelling through the barrel.
An aluminium hat with four longitudal weakenings at 90 degrees each containing the expelling charge is placed in the top of the upper (aluminium) piece. The upper rim of the hat is rolled outward to lock it into the upper piece. The powder for the expelling charge M10 powder and it is packed in a nylon bag. On top of this aluminium hat a steel filler disc is placed, locking up the powder charge. Screwing the fuze on the projectile locks up the ring.
Functioning of the projectile:
Before firing, the fuze is set on airburst on a point at approximately 300 mtrs above the ground.
When the time fuze ignites on the set time, the flame enters the detonator in the centrifugal safety element. The flame of the detonator ignites the powder of the expelling charge. The gasses rip open the aluminium hat over the four longitudal weakenings, filling the combustion chamber and starting to press upon the piston, up to a moment where the four windings of thread are ripped away and the cargo of 88 M42/M46 submunitions are dispersed (centrifugal force) from the base of the projectile. Depending upon the trajectory angle and speed, a round or an elipse shaped impact pattern of submunitions will occur.
Submunition M42 / M46, description and functioning:
The cargo of this projectile is made of 56 M42/M46 HEAT Frag (High Explosive Anti Tank Fragmentation)submunitions, placed in 7 columns of 8pcs. Six columns in a circular pattern around one column in the center. The submunitions are placed cone forward, the impact fuze M233 of the submunition stored in the cone of the submunition below. On the outer circumference of the submunitions the space between the submunitions and the inner wall of the projectile is filled with triangular nylon filler pieces, tightly locking up the submunitions. Three of these outer rows of filler pieces (at 120 degr. each) are made of aluminium and have a key on the outside that fits into the three keyways in the inside of the body, preventing the cargo of submunitions from radial movement compared to the projectile body on firing.
With regards, DJH
