Description
The BLU-97/B and BLU-97A/B bombs are small, aerially dispensed, decelerator stabilized, shaped charge, antimaterial/antitank bombs. They contain a fuzing system that provides a primary firing system for impact (standoff) firing and a secondary firing system for impact (semi-all-way) firing.
The bomb body is prescored on the inside surface for improved fragmentation. A 70 degree copper cone is attached to the forward end of the bomb body to form the shaped charge liner. The booster is housed in a sealed aluminum cup at the bottom of the fuze well and surrounded by a zirconium ring to provide an incendiary capability. The fuze is contained within the fuze can in the bomb body. The can is environmentally sealed to the fuze collar. The fuze contains a primary and a secondary firing system. The primary firing system consists of the primary firing pin and M55 detonator, located in the support collar, a piezoelectric crystal and an electrical cable, located in the fuze collar, and the Mk 96 detonator located in the rotor. The required electrical impulse to fire the Mk 96 detonator in the fuze rotor requires the functioning of the M55 detonator to stress the piezoelectric crystal. The electromechanical secondary firing system used in the BLU-97/B bomb has a semi-all-way graze sensitive feature. It consists of the firing pin, firing pin spring, lockballs, firing pin retainer, inertia ball, secondary cable assembly, piezoelectric crystal, and M55 detonator, all located in the fuze body. It is electrically connected, in the armed condition, to the same Mk 96 detonator as the primary firing system. The secondary firing lockpin interfaces with a detonator rotor shaft. The all-mechanical secondary firing system used in the BLU-97A/B bomb has a semi-all-way graze sensitive feature. It consists of the two inertia balls, a firing pin retainer, two lockballs, firing pin spring, secondary firing pin, bushing, detonator retainer, M55 detonator, detonator support, a spring plate, a ball support spring, and a spring retainer. The M55 detonator is explosively connected, through propagation holes in the detonator retainer and rotor in the armed condition, to the same Mk 96 detonator as the primary firing system. The secondary firing lockpin holds this system in a locked safe position until the rotor has rotated to the armed position.
These bombs are painted yellow and have nomenclature, loading data, and identifying numbers stenciled in black on the side of the standoff probe.
Functioning
The bombs consist of a standoff probe, fragmenting case, support collar, fuze, and an air-inflated decelerator (AID) or a ram air-inflated decelerator (RAD). The standoff probe is a spring-loaded drawn cylinder which houses the bomb body prior to deployment. After deployment, it acts as a standoff driving force at impact for the primary fuzing system. The probe is held in the deployed position by a conical spring and a stop clip and in the undeployed position by four or six wind tabs attached to the cup assembly. The bomb body is a formed piece of carbon steel rolled into a tube. The aft end of the body is tapered to a smaller diameter and threaded to receive the fuze. A circumferential groove is milled inside at the forward end of the bomb body to receive the shaped charge liner. The plastic support collar fits over the aft end of the bomb body with its aft surface interfacing with the outer housing of the fuze collar. The support collar serves as a surface over which the standoff probe can slide. A channel is drilled into the collar to house and guide the primary firing pin and to contain the M55 stab detonator of the primary firing system. The primary firing pin is a formed piece of stainless steel sharpened to a point at one end. When the bomb is in the undeployed condition, the primary firing pin is folded into the channel recess in the support collar, and the standoff probe is compressed over the pin and collar and secured by the wind tabs. In the deployed condition, the standoff probe is extended, permitting the primary firing pin to spring out of its recess and over top of the probe. The fuze is contained inside of the bomb body and secured to the body by the fuze collar. The AID/RAD canopy is an air-inflated, nylon stabilizer which is stored in the cup assembly. When deployed, it slows bomb velocity and orients trajectory for proper target impact. Scoop-covered holes, located in the aft section of the canopy, allow the canopy to inflate when exposed to the airstream. Currently, only the BLU-97A/B bomb is equipped with a RAD.
Hazardous Components
No information about hazardous components.
See Also
Nothing else to see.
Source(s)
Afghanistan Ordnance ID Guide, Volume 1 (2004)
Iraq Ordnance Identification Guide (2004)
