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Blu 26/b, 42/b, 61/b, 63/b, m38/40


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Description of the clusterbombs:

CBU / Cluster Bomb Unit: Clusterbomb (container housing the clusterbombs)
BLU / Bomb Live Unit : Single bomb from clusterbom container

The BLU-26/B "Guava" was an air-dispensed APAM (anti-personnel/anti-material) fragmentation bomblet with 600 embedded steel fragments. The BLU-26/B had three different fuzing options. It could detonate immediately on impact, as an airburst 9 m (30 ft) above ground, or after a selectable but fixed time after impact. The externally identical BLU-36/B and BLU-59/B had random-delay fuzes.

The BLU-26/B was used as payload in the following cluster bombs:

CBU-23/B (BLU-26/B in SUU-31/B)
CBU-24/B (665 BLU-26/B or BLU-36/B in SUU-30/B)
CBU-24A/B (665 BLU-26/B or BLU-36/B in SUU-30A/B)
CBU-24B/B (665 BLU-26/B or BLU-36/B in SUU-30B/B)
CBU-24C/B (665 BLU-26/B or BLU-36/B in SUU-30C/B)

In 1966/67, the BLU-26/B bomblet was also evaluated as a payload for the AGM-12C Bullpup guided missile. These tests probably led to the development of the AGM-12E variant, which had an anti-personnel cluster bomb warhead using BLU-26/B bomblets.

Data for BLU-26/B:
Diameter: 64 mm (2.5 in)
Weight: 435 g (0.95 lb)
Explosive: 85 g (0.19 lb) Cyclotol

The BLU-36/B was a variant of the BLU-26/B APAM (anti-personnel/anti-material) fragmentation bomblet with a randomly timed delay fuze, i.e. it detonated at an unpredictable time after impact.

The BLU-36/B was used as payload in the following cluster bombs:

CBU-24/B (665 BLU-26/B or BLU-36/B in SUU-30/B)
CBU-24A/B (665 BLU-26/B or BLU-36/B in SUU-30A/B)
CBU-24B/B (665 BLU-26/B or BLU-36/B in SUU-30B/B)
CBU-24C/B (665 BLU-26/B or BLU-36/B in SUU-30C/B)
CBU-29/B (670 BLU-36/B in SUU-30/B)
CBU-29A/B (670 BLU-36/B in SUU-30A/B)
CBU-29B/B (670 BLU-36/B in SUU-30B/B)
CBU-29C/B (670 BLU-36/B in SUU-30C/B)

Data for BLU-36/B:
Diameter: 64 mm (2.5 in)
Weight: 435 g (0.95 lb)
Explosive: 85 g (0.19 lb) Cyclotol

The BLU-61/B was an aerially dispensed anti-material fragmentation and incendiary bomblet. It was spin-armed and detonated on impact. The bomblet consisted of two hemispheres, both with a fragmentation liner of coined steel and a liner for zirconium-tin for the incendiary effect. There was also a BLU-61A/B version, but information about the differences is not available. The BLU-61A/B was apparently the primary (and possibly only) variant used in service.

The BLU-61A/B was used as payload in the following cluster bombs:

CBU-52/B (217 BLU-61A/B in SUU-30B)
CBU-52A/B (217 BLU-61A/B in SUU-30A/B)
CBU-52B/B (217 BLU-61A/B in SUU-30B/B)
CBU-76/B (290 BLU-61A/B in SUU-51B/B)

Data for BLU-61A/B:
Diameter: 99 mm (3.9 in)
Weight: 1.2 kg (2.6 lb)
Explosive: 277 g (0.61 lb) Octol

The BLU-63/B was an aerially dispensed, centrifugally-armed, impact-fired anti-personnel/anti-material fragmentation bomblet. There was also a BLU-63A/B version, but confirmed information about the differences is not available (the -63A/B possibly had a secondary incendiary effect). The BLU-86( )/B series was externally identical to the BLU-63( )/B, but had a time-delayed fuze.

The BLU-63( )/B was used as payload in the following cluster bombs:

CBU-58/B (650 BLU-63/B in SUU-30A/B)
CBU-58A/B (650 BLU-63A/B in SUU-30A/B)
CBU-75/B (1800 BLU-63/B in SUU-54A/B)
CBU-75A/B (1420 BLU-63/B and 355 BLU-86/B in SUU-54A/B)
CBU-77/B (790 BLU-63/B in SUU-51B/B)

The CBU-75/B could be fitted with a KMU-421/B Paveway laser guidance kit, resulting in the GBU-2/B PAVE STORM guided bomb.
Data for BLU-63/B:
Diameter: 76 mm (3 in)
Weight: 0.45 kg (1 lb)
Explosive: 113 g (0.25 lb) Cyclotol.

The BLU-63b was also used in Army Rocket artillery like the Lance missile and ATACMS, it was than called The M74 grenade. The fuse used in these missiles was the M219E2, which differs from the M219E1 in lubricant. 300pcs of M74 grenades were packed in the warhead of the Lance missile.

The BLU-42/B WAAPM (Wide-Area Anti-Personnel Mine) was a spherical anti-personnel fragmentation minelet. It was fitted with several surface and trip-wire sensors for detonation, an anti-tampering device, and a self-destruct system. There was also a BLU-42A/B variant, but no information about the differences is available. The BLU-54/B was externally identical to the BLU-42( )/B, but had a long-life self-destruct system.

The BLU-42( )/B was used as payload in the following cluster bombs:

CBU-34/A (540 BLU-42( )/B (10 CDU-18/B or CDU-19/B clusters of 54 mines each) in SUU-38/A

Data for BLU-42/B:
Diameter: 60 mm (2.38 in)
Weight: 500 g (1.1 lb)
Explosive: 71 g (0.15 lb) Composition-B

The M38/M40,
A smaller version of the ball shaped clusterbombs. The bomblet is also rotation armed. 950 pcs. Were packed in the warhead of the Lance missile.
Diameter: 45 mm
No further info about grenade or fuze is available. The M38/M40 in the picture is a dummy.

The blue dummy is of an unknown type designation , however of US manufacturing
Diameter: 48 mm

An interesting piece of movie where this type of CBUs can be seen in action:
[ame="http://www.youtube.com/watch?v=bYXdk-qTl5U&feature=related"]YouTube- US Air Force dropping Cluster Bombs...[/ame]

Description of impact fuze M-219(E1);
The fuze exists of an upper (1) and lower body (2). The fuze is rotation armed. After relaese from the CBU (Clusterbomb container) or missile the ribs (flutes) on the outside of the body of the clusterbomb start to cause rotation untill the clusterbomb rotates very fast.

The lower body (1) houses the rotation safety shutter (3), the spring loaded centrifugal safety segments (4), the firing cap (5) and the detonator (8). When rotating fast, the four centrifugal weights that lock the rotation safety shutter in safe position are thrown outward, overriding the springs (6). The rotation safety shutter is now free to rotate and the firing cap (7) is (spring)rotated over the detonator (8) and below the firing pin (9).
The upper body (2) houses the arming vane (10) with its rotation spring (11), the arming vane relase lever (12), the firing pin (9) and its blade spring (13), the locking ball (14) for the firing pin and the bag with gel(15).
On release the fast rotation of the clusterbomb throws the gel in the bag (blue) outward, thereby flattening the bag, creating enough space for the arming vane to rotate. The arming vane is rotated by means of a rotation wire spring (11). The arming vane release (yellow, 12) keeps a blade spring (red, above the release vane) in upward position, blocking the arming vane (10) from rotating.
When, -after release from the CBU - the rotation safety shutter (3) rotates, it turns the arming vane release - hooked in a slot in the rotation safety shutter with its lower part-, so enabeling the blade spring to move down and release the arming vane.
The firing pin(9) is (blade)spring (13) loaded and has a recess in top in which a small ball (14) fits, keeping the firing pin in upward position. The arming vane has a slot on the outer circumference of its shaft in which the ball fits, releasing the firing pin when the slot has rotated in line with the ball.
In the picture it can be observed two types of arming vanes are used;

type 1 with one slot (red arrow), meaning after rotating the arming vane the firing pin is released, exploding the clusterbomb, either in the air or on the ground.

The type 2 has two slots (blue and red arrow); after rotation of the arming vane, the ball will fall into the first slot (blue arrow). As there is still spring tension on the arming vane by the rotation spring (11), the arming vane will have to rotate/creep to the red slot beside it to release the firing pin.
I am not treally shure what happens next, but there are in my opinion- two possibillities:

* impact will make the ball (14) jump the next (red arrow) slot releasing the firing pin, exploding the clusterbomb instantly. (impact fuze)

*After impact the rotation spring (11) will slowly start to rotate (creep) the arming vane, pushing away the gel in the bag until the ball falls in the next (red) slot, releasing the firing pin and exploding the clusterbomb. This forms a random time delay. As the clusterbomb does not rotate anymore after impact, the bag of gel has retaken its original form causing more resistance than in a rotating clusterbomb. This increased resistance lengthens the time delay.
I suppose the delay will probably also be dependant on the outside temperature as the gel in the bag will be thicker either thinner when used in artic either tropical conditions.

I am not shure -maybe someone can tell me- that the fuze with the type 2 vane is the M-218 (0-120 minutes) random delay fuze or the M224 (0-30 minutes) random delay fuze. I have no further drawings, descriptions or info of this type of fuze.

Regards , DJH


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Impact fuze M219(E1)

fuze details


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Impact fuze M219(E1)

More fuze details


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weapons using BLU's

Clusterbomb and Lance warhead


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You're welcome. Returning to the current posting about cutting on not cutting ; try to explain this fuze without cutting it
So the only way this fuze will detonate on impact is if the ball is dislodged on hitting the ground? That would imply that if the BLU hits the ground at the wrong angle, the ball stays in position - thus creating a dud?
The impact angle was predicted by the spin ribs which caused a rotation around one particular (intended) axis.
Yeah - but still. If the ball is lodged against the firing pin, if the ball impacts the ground with the ball in line with the support of the pin - there's no way the ball will dislodge, or have I got it wrong? Thanks for the info btw!
I do not think the picture is a Lance. I think that the picture shows the US Honest John missile and M139 bomblets. US-Subs may know more.

Your are correct, it is the Honest John, I've got the warhead model number around here somewhere. The Lance gets mistaken sometimes in that it had HE, submunition, nuclear, chemical and biological warheads designed for it, but as far as I've ever found it was never intended to carry the M139, as pictured in the Honest John warhead above. Further confusing things, one of the Lance warheads was designed to carry the E139 GB (nerve agent) submunition, which despite the designation is nothing like the M139 GB submunition. The E139 was smaller and cylindrical.

The warhead shown is a fairly common photo of the Honest John warhead filled with M139s. The giveaway is the number of submunitions that can be seen from side to side, this gives an approximation of the width, much too large for the Lance. Much more difficult is the more rare photos of the M139 in the Little John or Corporal missile warheads, both designated carriers and much closer to the Lance in size.

I've attached photos of the spherical M139, the E139 and one of the the Lance warheads (E27) designed to carry the E139.

M139  1.jpg D-SUB-US-CB-104.jpg Lance E27 WH.jpg

I haven't ever seen tabs on the side of the M139 before this photo. What's the story on the tabs?
There were many variations of the M139 where they were trying to stabilize the spinnning for better pattern distribution. As far as I understand it is one of the problems of a light munition with a high percentage of liquid fill. The tabs appear in a number of variations, usually in groups of two. I've also got some that had more vanes, transverse fuzing, etc. CW developmental pieces were given "E" numbers, the modifications had an "R" designation. So you would have an E139, E139R1, E139R2 etc. Trying to reference them can be a nightmare, many of the pubs are gone or archived under reference numbers that make no sense today.
I described the M139 over here:

Jeff is right about the tabs on the outside, mine differ slightly in shape from the ones on his picture.
Also learned something today as I suspected they were meant to keep the clustermunition fixated with clamps like grapes on a vine as to obtain a controlled release over the target.

Rewgards, DJH
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As far as I can recall the US did that with only one submunition, an undesignated steel sphere that had a sort of "bayonet" locking lug, used to attach the submunition to a "Christmas tree" sort of assembly. This was built for use in the Nike Zeus, intended for intercept of incoming nuclear missiles back in the 1960s or so. An elaborate setup, the concept as I recall it was to have an expulsion charge of sorts, which would discharge the submunitions from the tree in a uniform pattern, following which they would detonate (pyrotechnic delay?) deploying a virtual wall of fragments. I've only seen one document that described this, and I had one of the submunitions for over 20 years before I was able to identify it, so I do not think that they lasted very long.