The BLU-97/B Combined Effects bomblet (submunition) was designed by Honeywell for use in the CBU-87/B cluster bomb. It's recently been put in the first variant of the Joint Standoff Weapon (JSOW).

From Jane's:

BLU stands for Bomb Live Unit and `B' refers to expendable weapon. The BLU-97/B was designed to have three destruct capabilities, hence the `combined effects' designation. A shaped charge can penetrate armour, a fragmentated body can hit personnel or disable trucks up to 18 m away, and a zirconium incendiary ring can start fires. These attributes make it an ideal weapon for use against a variety of targets in the field including tank and light armour formations, convoys, munition dumps and parked aircraft.

The BLU-97/B bomblet is basically a cylindrical canister-type bomb fitted with a Ballute parachute retarding tail unit, and an ejection front-projecting tube used to sense the optimum standoff distance for activating the shaped charge explosive. Before ejection the bomblet is 0.169 m long, has a body diameter of 64 mm and weighs 1.5 kg. Once ejected and activated the bomblet extends to a length of 0.356 m. The bomblet warhead consists of a fragmenting case which has a 287 g shaped charge of Cyclotol and Zirconium which provides an incendiary element. Before release the aircrew can select in-flight either one of two delivery modes for the CBU: timed or proximity. In the timed mode the cluster bomb opens at a preset time after weapon release. This time is ground-selectable from 0.63 to 4.15 seconds in 12 settings. In the proximity mode the dispenser opens at a preset height above the ground. This height is also ground-selectable from 90 to 900 m in 10 settings. An optional Doppler radar proximity fuze (FZU-39/B) can also be used to arm and open the CBU at heights between 90 and 900 m. This can be useful in high-threat areas where the target can be visually acquired and the bombs lofted in its direction while the delivery aircraft leaves the area. On being released from the parent aircraft the CBU-87/B falls away and the rear fins extend and cant in such a manner to cause the CBU to spin at a preselected rate. The spin effect gives controlled bomblet dispersion following the opening of the casing. Spin rate options are in 500 rpm increments from 0 to 2,500 rpm. Simultaneous with the fin opening 80 ms after release, a thermal battery is activated to provide power to the fuze system, this power also fires an explosive bolt which cants the four fins. Normal cant angle is 56 from centreline. At 700 kt release speed these canted fins can provide the CBU with a full 2,500 rpm spin rate in less than 0.5 seconds. At the predetermined time or altitude the CBU casing opens and the bomblets are dispersed. At between 0.45 and 0.8 seconds after leaving the CBU container the bomblets' fuzing system is armed and the rear end Ballute parachute is expelled to reduce the bomblets' forward velocity. The parachute also ensures that the bomblet stikes the target area at an optimum angle to provide maximum destructive effect. At detonation the fragmented steel body disintegrates and produces scores of 30 g fragments capable of immobilising light armour at 15 m, damaging aircraft at 75 m and injuring personnel at 150 m. These fragments are credited with the ability to penetrate 6.4 mm of steel plate at 11 m. The shaped charge itself can penetrate 125 mm armour plate and is ideal for attacking the top surface of tanks. It also causes a spalling effect behind the armour and it is capable of piercing 190 mm of mild steel. Furthermore the bomblet contains a zirconium sponge ring which the explosive charge breaks up causing burning particles to saturate the target area, thus initiating petrol and diesel fires if these materials are present. Initiation of the explosive chain is by means of a piezoelectric detonator in the fuze assembly. In turn this sets off a stab detonator which then fires the primary shaped charge.

The CBU-87/B can be released between speeds of 200 and 700 kt at altitudes between 60 and 1,200
m and in climb angles up to 30 and in dive angles down to 60.

Following concern regarding the number of unexploded BLU-97 bomblets found after the Kosovo campaign in 1999, the USAF started to investigate ways to improve the weapon. The problem requires a power supply within each bomblet to initiate an explosion after a predetermined time, but this would increase the size of each bomblet and result in fewer being carried in each CBU-87/B.

Specifications
CBU-87/B
Length: 2.33 m
Body diameter: 396 mm
Tailspan: 0.52 m (closed); 1.07 m (extended)
Lug spacing: 356 mm
Weight: 430 kg
Filling: 202 BLU-97/B bomblets

BLU-97/B CEM bomblet
Length: 0.169 m stowed
Body diameter: 64 mm
Tailspan: n/a
Lug spacing: n/a
Weight: 1.5 kg
Filling: 287 g 70/30 Cyclotol/Zirconium




During the war on Afghanistan, the US embarrassed itself when it dropped cluster bombs on the same areas into which it was dropping aid packets. There's a constant nonzero failure rate in BLU-97 submunitions, and you can see why the unexploded submunitions were so easily mistaken for aid packets


I found a Japanese site with diagrams of BLU-97's. I thought they were cute.