Army Rumour Service

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

WW2 shaped charge bomblets question?

jrwlynch

LE
Book Reviewer
One intended for @Listy but open to anyone interested.

During WW2, the Soviets had the 2.5kg PTAB shaped-charge bomblet, which they dropped a good few million of onto assorted opponents.

Now, we knew about shaped charges, we knew about dropping lots of 4lb incendiaries bundled up in Small Bomb Containers, we were turning out PIAT bombs that on an "I don't have to do it so it's easy" basis could have been made into the payload of antitank cluster bombs. So, it doesn't seem that we couldn't do it, but we didn't.

Is it that we never thought of the idea? Or was it looked at and decided that it wasn't good enough to divert design and production, and displace 1000lb bombs or RP-3 rockets on Typhoons, for?

Is it as simple as these things work nicely on open steppe, but in wooded European terrain you'd get lots of them dangling from trees like twitchy high-explosive fruit?
 

4(T)

LE
One intended for @Listy but open to anyone interested.

During WW2, the Soviets had the 2.5kg PTAB shaped-charge bomblet, which they dropped a good few million of onto assorted opponents.

Now, we knew about shaped charges, we knew about dropping lots of 4lb incendiaries bundled up in Small Bomb Containers, we were turning out PIAT bombs that on an "I don't have to do it so it's easy" basis could have been made into the payload of antitank cluster bombs. So, it doesn't seem that we couldn't do it, but we didn't.

Is it that we never thought of the idea? Or was it looked at and decided that it wasn't good enough to divert design and production, and displace 1000lb bombs or RP-3 rockets on Typhoons, for?

Is it as simple as these things work nicely on open steppe, but in wooded European terrain you'd get lots of them dangling from trees like twitchy high-explosive fruit?


Possibly it was considered that there just weren't enough hard armour targets in France to justify deployment, and that general purpose HE/fragmentation types were more operationally efficient.
 
The Americans had the M29 (I think it was), but the failure rate was such that it was recommended they not be used in areas which were expected to soon be occupied by friendly troops given the large number of bomblets which would need to be cleared.
 
One intended for @Listy but open to anyone interested.

During WW2, the Soviets had the 2.5kg PTAB shaped-charge bomblet, which they dropped a good few million of onto assorted opponents.

Now, we knew about shaped charges, we knew about dropping lots of 4lb incendiaries bundled up in Small Bomb Containers, we were turning out PIAT bombs that on an "I don't have to do it so it's easy" basis could have been made into the payload of antitank cluster bombs. So, it doesn't seem that we couldn't do it, but we didn't.

Is it that we never thought of the idea? Or was it looked at and decided that it wasn't good enough to divert design and production, and displace 1000lb bombs or RP-3 rockets on Typhoons, for?

Is it as simple as these things work nicely on open steppe, but in wooded European terrain you'd get lots of them dangling from trees like twitchy high-explosive fruit?

Does it have to be Hollow Charge? Or can I have HESH?

Look at the 9Lb Atk Mk.I. Also called 'Puffball' or the 'Jefferis' AT bomb. 24x bombs per SBC. At least 50,000 manufactured by about mid 1942, and there was discussion of another 25,000 being ordered.
Designed by Millis Jefferis. Tested agaisnt submarines, Merchants and trains (Train was hit needed 3 weeks to repair it) as well as tanks. The targets were restricted due to lack of production, as it's a HESH warhead, and the Nobels 808 was needed for other uses, so there were never enough to go around.
It seems to have been caught up in inter-service rivalry at this point, and was handed over to Bomber Command.
Used during the 1,000 bomber raid on Cologne in the Intruder role. Basically 2 group hit a load of German Airfields to suppress the Night Fighters. Words were had about this misuse of ordnance. This was down to the limited production, so their use had to be approved by Bomber Harris.
Commander of 2Grp promptly ignored the 'words', as they were highly valued for blowing up airfields, and used them for SEAD on a raid on Breman on the 25/26th of June 1942.

MELF asked for 5,000. But promptly lost most of their allocated stock (~11,000 bombs) at Toburk. In addition they were disliked due to the time needed to load a SBC with bombs and the fact the bomb had to hit the target. I have some accounts of their success. But it was considered a 40mm Hurricane was more effective, due to no random factor in the spread of the bombs.

About halfway through 1943 the remaining stock was attempted to be passed to Army-Cooperation Command, who said No thanks.
May 43: Listed as surplus to requirements.
June 43: Order to scrap all bombs issued.
 
Significant problems with Puffball were sympathetic explosions in mid-air and, when used as designed at low-level from a fighter-bomber, blast/frag damage to the aircraft. The official RAF rating in 1943 of AT weapons was, in descending order:
1) 40mm
2) 20mm Hispano (with later marks of AP shot)
3) 25lb AP RP
4) 60lb HE RP
5) 0.5"
6) Puffball

Of course, by 1944, 60lb HE RP had climbed to the top. 40mm was still highly rated, and vastly more accurate, but, at least in NW Europe, the Hurricanes were deemed too vulnerable. No.20 Sqn was still flying them as late as June 45 against the Japanese, though.
 
One intended for @Listy but open to anyone interested.

During WW2, the Soviets had the 2.5kg PTAB shaped-charge bomblet, which they dropped a good few million of onto assorted opponents.

Now, we knew about shaped charges, we knew about dropping lots of 4lb incendiaries bundled up in Small Bomb Containers, we were turning out PIAT bombs that on an "I don't have to do it so it's easy" basis could have been made into the payload of antitank cluster bombs. So, it doesn't seem that we couldn't do it, but we didn't.

Is it that we never thought of the idea? Or was it looked at and decided that it wasn't good enough to divert design and production, and displace 1000lb bombs or RP-3 rockets on Typhoons, for?

Is it as simple as these things work nicely on open steppe, but in wooded European terrain you'd get lots of them dangling from trees like twitchy high-explosive fruit?

You certainly do get cluster munitions hung up in trees etc. I’ve encountered them myself several times

I wonder if there is a two-fold explanation.

The first being of more effective* weapons being available, such as the 60lb rocket.

The second being an institutional bias. The RAF was the first Independent airforce with emphasis on ‘strategic’ bombing. It was a comparative early adaptor of cluster munitions in the form of incendiaries but they were a key part of strategic ‘area’ bombing in a way that HEAT (or even HEDP) cluster munitions weren’t.

Even the Germans, who invented the HE cluster munition after BDA in Spain, effectively binned them after our disinformation ops via the XX committee told them they were useless (even while it told us - and the Americans - what a jolly good idea they were.

I think the result of these two factors may have combined to the relatively late adoption of HEAT/HEDP CM in the west. Off the top of my head the BLU-3 is the earliest.





* To a given value of ‘effective’ of course.
 
Significant problems with Puffball were sympathetic explosions in mid-air and, when used as designed at low-level from a fighter-bomber, blast/frag damage to the aircraft. The official RAF rating in 1943 of AT weapons was, in descending order:
1) 40mm
2) 20mm Hispano (with later marks of AP shot)
3) 25lb AP RP
4) 60lb HE RP
5) 0.5"
6) Puffball

Of course, by 1944, 60lb HE RP had climbed to the top. 40mm was still highly rated, and vastly more accurate, but, at least in NW Europe, the Hurricanes were deemed too vulnerable. No.20 Sqn was still flying them as late as June 45 against the Japanese, though.

And, of course, the 40mm was less able to penetrate the armour of German tanks by 1944, although still not to be sniffed at. This was why we have the Molins gun (the thought of Mosquitos roaming above the Falaise battlefield pinging 57mm rounds into various Panzer types is an image to conjure with...).

You also get:

1602249461333.png


As covered by Anthony G Williams

The Molins gun was much more accurate than the 3in RP, but as the latter was more versatile and could be hung from fighter-bombers rather than requiring a special aircraft type to carry it, the Molins fell from favour first as the projected airborne AT gun and then as a widespread weapon in Coastal Command. That said, the Mossie FBXVIIIs caused some 'interesting' moments for a range of German shipping types and, IIRC, at least one fighter which rapidly turned itself into an airborne jigsaw kit when a Mossie pilot hit it with a round from the Molins gun.
 

HE117

LE
HEAT warheads really only started to be deployed by the Allies from about 1940 for some reason.. The Germans had been using them since the 30s and the famous glider borne attack on the Eban Emael forts was done with shaped charges..

The performance of shaped charges is based on three factors:

1. Charge diameter. This is the main factor.. penetration, all things being equal, is down to the diameter of the charge.
2. Accuracy of the cone manufacture and the material used. The cone material chosen is usually something ductile.. Copper is the usual choice, but silver and gold work as well. The symmetry of the construction is however a major issue, and contributes greatly to the yield/penetration.
3. The final issue is fuzing. A shaped charge has to be initiated in front of the target to allow the jet to form. This is a tricky process and has to work to very tight parameters. It was not until electrical/electronic fuzing was developed that this was consistently achieved.

First generation shaped charges were really not very good, reliable or indeed safe...! The Sovs were also a lot less concerned with weapon safety than some of the other nations! Shaped charge bomb designs were pretty rare.. the Germans had some but the west did not rate them, and concentrated more on blast and incendiary designs which were cheap and simple, and ultimately successful!
 
Last edited:

Mufulira

War Hero
Significant problems with Puffball were sympathetic explosions in mid-air and, when used as designed at low-level from a fighter-bomber, blast/frag damage to the aircraft. The official RAF rating in 1943 of AT weapons was, in descending order:
1) 40mm
2) 20mm Hispano (with later marks of AP shot)
3) 25lb AP RP
4) 60lb HE RP
5) 0.5"
6) Puffball

Of course, by 1944, 60lb HE RP had climbed to the top. 40mm was still highly rated, and vastly more accurate, but, at least in NW Europe, the Hurricanes were deemed too vulnerable. No.20 Sqn was still flying them as late as June 45 against the Japanese, though.
If Nobel 808 was used as a filler then sympathetic detonations could certainly occur as it was NG based and not totally safe from accidental 'thumps' --- where else could you get a headache so quickly. Line workers prepping NG quite often built up a tolerance for the sweet smelling stuff and would smear some on their hat or cap interior liners when on leave so would still get their daily 'dose'.
 
Is it that we never thought of the idea? Or was it looked at and decided that it wasn't good enough to divert design and production, and displace 1000lb bombs or RP-3 rockets on Typhoons, for?

Is it as simple as these things work nicely on open steppe, but in wooded European terrain you'd get lots of them dangling from trees like twitchy high-explosive fruit?

I think it’s simply a matter of choice. The Russians went down the shaped charged route and tailored their tactics and equipment to it, we went down another route preferring HESH/AP/HE.
 
HEAT warheads really only started to be deployed by the Allies from about 1940 for some reason.. The Germans had been using them since the 30s and the famous glider borne attack on the Eban Emael forts was done with shaped charges..

The performance of shaped charges is based on three factors:

1. Charge diameter. This is the main factor.. penetration, all things being equal, is down to the diameter of the charge.
2. Accuracy of the cone manufacture and the material used. The cone material chosen is usually something ductile.. Copper is the usual choice, but silver and gold work as well. The symmetry of the construction is however a major issue, and contributes greatly to the yeald/penetration.
3. The final issue is fuzing. A shaped charge has to be initiated in front of the target to allow the jet to form. This is a tricky process and has to work to very tight parameters. It was not until electrical/electronic fuzing was developed that this was consistently achieved.

First generation shaped charges were really not very good, reliable or indeed safe...! The Sovs were also a lot less concerned with weapon safety than some of the other nations! Shaped charge bomb designs were pretty rare.. the Germans had some but the west did not rate them, and concentrated more on blast and incendiary designs which were cheap and simple, and ultimately successful!
I remember seeing the drawing for one US shaped charge weapon using a tantalum liner

Sent from my SM-T510 using Tapatalk
 

HE117

LE
I think it’s simply a matter of choice. The Russians went down the shaped charged route and tailored their tactics and equipment to it, we went down another route preferring HESH/AP/HE.

The FROG/Luna missile warhead had a shaped charge... why*?

1602270616167.png


* Rhetorical question.. I have no idea why putting a shaped charge on an unguided bombardment missile was thought a good idea..!
 

Pteranadon

LE
Book Reviewer
And, of course, the 40mm was less able to penetrate the armour of German tanks by 1944, although still not to be sniffed at. This was why we have the Molins gun (the thought of Mosquitos roaming above the Falaise battlefield pinging 57mm rounds into various Panzer types is an image to conjure with...).

You also get:

View attachment 510902

As covered by Anthony G Williams

The Molins gun was much more accurate than the 3in RP, but as the latter was more versatile and could be hung from fighter-bombers rather than requiring a special aircraft type to carry it, the Molins fell from favour first as the projected airborne AT gun and then as a widespread weapon in Coastal Command. That said, the Mossie FBXVIIIs caused some 'interesting' moments for a range of German shipping types and, IIRC, at least one fighter which rapidly turned itself into an airborne jigsaw kit when a Mossie pilot hit it with a round from the Molins gun.
Sorry but the casualty rate among anti tank gun aircraft was far too high to justify the losses in aircraft. Hitting a tank with a gun meant getting to within about 200- 100m -same as air to air combat. Return ground fire could be fatal. RP salvos against area targets were launched from 4,000 feet and individual tanks from 500-1000 yards. A more survivable profile.

I have a hypothesis that over Normandy the allied air forces lost far more than physical damage inflicted on German ground forces. This was masked by rampant over claiming by airmen. The allies scaled back their air to ground effort in July 1944 because of the high losses. I don't think there has been an academic study on this topic...

Of course the morale impact of allied air power weighed heavily in its favour.
 

jrwlynch

LE
Book Reviewer
I have a hypothesis that over Normandy the allied air forces lost far more than physical damage inflicted on German ground forces. This was masked by rampant over claiming by airmen. The allies scaled back their air to ground effort in July 1944 because of the high losses. I don't think there has been an academic study on this topic...

Of course the morale impact of allied air power weighed heavily in its favour.

It's pretty well researched how serious the overclaiming was (even at the time, as the ORS was recording), but also the fact that - as the debriefings of captured Panzer crews quoted by Gooderson explain - the number of abandoned tanks, undamaged but with crews fled, was due in large measure to air attack.

Prisoner of war data further confirmed the demoralising effect of air attack upon tank crews. German tank crewmen questioned for the later joint RAF/British Army study of Typhoon effectiveness indicated an irrational compulsion among inexperienced men to leave the relative safety of their tank and seek alternative cover during air attack:

"The experienced crews stated that when attacked from the air they remained in their tanks which had no more than superficial damage (cannon strikes or near misses from bombs). They had a great difficulty in preventing the inexperienced men from baling out when our aircraft attacked."

It is certainly plausible that tank crews under a heavy scale of air attack would be induced to bale out, despite the interior of the tank being possibly the safest place to be, and in this way the bombs and rockets did not need to strike the tanks to be effective. When asked for an opinion by the ORS on the number of abandoned tanks in the
Mortain battle area, an experienced NCO of a US anti-tank unit replied,


"There is nothing but air attack that would make a Panzer crew do that."
Air attack had serious impact on the victims, even if it didn't often inflict battle-winning damage and casualties by itself. A key lesson was the need to immediately exploit the disorientation and confusion an air attack caused.
 

Latest Threads

Top