PzGr40
11.02.2008, 04:34
Cutaway model of a M80 submunition. The M80 is used in the type M915 and M916 projectiles of the US army 105mm (M119A1) howitzers, both containing 42 pcs. of M80 submunitions, the M984 120 mm Extended range DPICM mortar cartridge (54 pcs of M80), and the Naval MK45 5inch 54 or 62 calibres gun. The Mk45 uses the ERGM round contaning 72 submunitions M80.
Purpose of the projectiles:
The purpose of these projectiles is to saturate an area with M80 submunitions (also called bomblets), thereby creating a more controlled fragmentation over a larger area -when compared to High explosive projectiles-, 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 High explosive shell, but as a supplement.
The M80 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.
The M80 is close family of the M42/46 and the M77 submunitions, although much smaller.
Functioning of the projectile:
Before firing, the fuze is set on airburst on a point at approximately 300 mtrs above the ground.
When the MT565 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 fill the combustion chamber and start to press upon the piston, up to a moment where the windings of thread of the base plug of the projectile are ripped away and the cargo of M80 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.
The fuze used on the M80 is the M233 impact fuze in a slightly modified shape. This fuze is made up of seven parts: The pressed sheet aluminium fuze housing (1), the slider (2, houses the firing cap), the slider spring (not visable), the hammer piece (3), the firing pin (4), the ribbon (5), the ribbon retainer (6).
On expelling, the airstream will release the ribbon out of the ribbon retainer. The ribbon stretches out and starts to vibrate in the airstream, unscrewing the firing pin from the hammer piece. A small flange just below the point of the firing pin falls into a recess in the hammer piece. In safe position , the point of the firing pin is placed in a hole in the slider, preventing the slider from moving outward aligning firing pin, firing cap and detonator. On impact , the firing pin moves downward together with the hammer piece into the firing cap, igniting the submunition.
The lethal fragmentationradius is 5 mtrs. Penetration of the hollow charge is stated to be 3 (76,2 mm) of steel. The cone diameter is 25,5 mm. The type of explosive than used is PAX-2A, (see page 20 :
http://www.dtic.mil/ndia/2003insensitive/geiss.pdf ).
The complete projectile with folded ribbon is 76 mm high, the body diameter is 30,8 mm.
An interesting development in improving the fuze of this small submunition electronically with a proximity function can be found here:
http://www.dtic.mil/ndia/2001gun/Martin2.pdf
See page 42 and 43 of this posting:
http://www.ee.buffalo.edu/academics/graduate/seminar/2006_07/DEC08_slides.pdf
Regards, DJH
Purpose of the projectiles:
The purpose of these projectiles is to saturate an area with M80 submunitions (also called bomblets), thereby creating a more controlled fragmentation over a larger area -when compared to High explosive projectiles-, 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 High explosive shell, but as a supplement.
The M80 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.
The M80 is close family of the M42/46 and the M77 submunitions, although much smaller.
Functioning of the projectile:
Before firing, the fuze is set on airburst on a point at approximately 300 mtrs above the ground.
When the MT565 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 fill the combustion chamber and start to press upon the piston, up to a moment where the windings of thread of the base plug of the projectile are ripped away and the cargo of M80 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.
The fuze used on the M80 is the M233 impact fuze in a slightly modified shape. This fuze is made up of seven parts: The pressed sheet aluminium fuze housing (1), the slider (2, houses the firing cap), the slider spring (not visable), the hammer piece (3), the firing pin (4), the ribbon (5), the ribbon retainer (6).
On expelling, the airstream will release the ribbon out of the ribbon retainer. The ribbon stretches out and starts to vibrate in the airstream, unscrewing the firing pin from the hammer piece. A small flange just below the point of the firing pin falls into a recess in the hammer piece. In safe position , the point of the firing pin is placed in a hole in the slider, preventing the slider from moving outward aligning firing pin, firing cap and detonator. On impact , the firing pin moves downward together with the hammer piece into the firing cap, igniting the submunition.
The lethal fragmentationradius is 5 mtrs. Penetration of the hollow charge is stated to be 3 (76,2 mm) of steel. The cone diameter is 25,5 mm. The type of explosive than used is PAX-2A, (see page 20 :
http://www.dtic.mil/ndia/2003insensitive/geiss.pdf ).
The complete projectile with folded ribbon is 76 mm high, the body diameter is 30,8 mm.
An interesting development in improving the fuze of this small submunition electronically with a proximity function can be found here:
http://www.dtic.mil/ndia/2001gun/Martin2.pdf
See page 42 and 43 of this posting:
http://www.ee.buffalo.edu/academics/graduate/seminar/2006_07/DEC08_slides.pdf
Regards, DJH