German VT shells?

[Scipio]

That's something I really don't know: the VT shell is in princip a shrapnel shell, it explodes a few meters over the ground, yes?

Why don't have the Axis this shells? They was already used in World War 1, maybe earlier, or I'm wrong here?

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[Guest Mike the bike]

Shrapnel shels as used in WW1 were timed fuses, so if the time was wrong they would not explode correctly in the air.

VT shell ALWAYS exploded at the right place if they weer working properly - if didn't matter if the range was right or wrong.

IIRC some country's may also have had a limited range of settings for their shrapnel - I vaguely recall some guns only being able to be set of ranges in multiples of 500 yards or metres?

[Guest Germanboy]

Originally posted by Mike the bike:

Shrapnel shels as used in WW1 were timed fuses, so if the time was wrong they would not explode correctly in the air.

VT shell ALWAYS exploded at the right place if they weer working properly - if didn't matter if the range was right or wrong.

IIRC some country's may also have had a limited range of settings for their shrapnel - I vaguely recall some guns only being able to be set of ranges in multiples of 500 yards or metres?

The Germans had MT fuses (as did the Allies) and the German AA guns (and probably Allied as well) had either fixed (light) or variable (heavy) timed fuses, where you could dial in a distance. This was used to create airbursts in direct fire mode on ground targets.

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[Guest barrold713]

IIRC, I saw a show on the History Channel that documented some of the "secret" technology that helped the allies win the war. One of the segments was on the proximity fuses developed for AA guns on naval ships. There was some sort of rudimentary radar in the shells that sensed when it was close to an object and detonated when it was within range to destroy the incoming planes.

They showed all of the research and testing that went into perfecting the design before being put into mass production and I found that part fascinating.

If memory serves, after they were proven a success, the technology was adapted to other types of artillery shells and I don't think the secret was discovered by the axis powers so they could not produce their own versions. They knew of the damage being done but not how it was being inflicted. I might have the details wrong so I am going to do some more research.

BDH

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[Gremlin]

Check here for detailed info on VT fuzes and their development.

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[ParaBellum]

Originally posted by barrold713:

IIRC, I saw a show on the History Channel that documented some of the "secret" technology that helped the allies win the war. One of the segments was on the proximity fuses developed for AA guns on naval ships.

BDH

IIRC german ships used that technique, too.

I read that the BB TIRPITZ used their 38cm main armament as flak against british Lancaster formations while stationed in a norwegian fjord as "fleet in being".

The shells were time-fused and were quite effectvie against large raids.

They could (through radar) open fire on distances up to 20 km.

I really would like to see an 38cm airbust!

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[Forever Babra]

Originally posted by ParaBellum:

[bI really would like to see an 38cm airbust!

OUCH! IIRC, Battleship Yamato used her 18-inch guns against aircraft as well, but the shell was a sort of monstrous shotgun affair, and not a timed burst. Pretty neat idea if ya ask me.

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[109 Gustav]

Originally posted by Forever Babra:

OUCH! IIRC, Battleship Yamato used her 18-inch guns against aircraft as well, but the shell was a sort of monstrous shotgun affair, and not a timed burst. Pretty neat idea if ya ask me.

IIRC, it didn't work very well. Not only did the shotgun shells wear out the gun barrels, but it turned out to be pretty hard to aim at an airplane moving at 300+ mph.

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[russellmz]

Originally posted by Forever Babra:

OUCH! IIRC, Battleship Yamato used her 18-inch guns against aircraft as well, but the shell was a sort of monstrous shotgun affair, and not a timed burst. Pretty neat idea if ya ask me.

too bad they didn't work.(actually, it's very good that they didn't work) the yamato used them on her final voyage and it damaged the gun barrels after a while...

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[This message has been edited by russellmz (edited 02-26-2001).]

[Forever Babra]

I was aware that it wasn't terribly effective, but it's still neat. Can you imagine if one of those blasts WAS aimed right and happened to pass through the same space as a dive bomber squadron? Yowza.

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[Bullethead]

Scipio said:

That's something I really don't know: the VT shell is in princip a shrapnel shell, it explodes a few meters over the ground, yes? Why don't have the Axis this shells? They was already used in World War 1, maybe earlier, or I'm wrong here?

Oh Gawd, you touch on one of my pet peeves..

As others have pointed out, true VT fuzes were an Allied monopoly and the Germans just had mechanical time fuzes.

However, as you point out, the whole airburst shell thing was very ancient. It dates back hundreds of years and the real Shrapnel shell (containing a bunch of small balls for added airburst fragmentation effect) was invented in the early 1800s. Once more or less modern types of shells were developed in the late 1800s, however, they had to also invent mechanical fuzes to create airbursts because the new shells sealed the propellant fire behind the shell so it couldn't light the old "firecracker" fuzes any more.

So mechanical time fuzes were definitely a mature technology by the time of WW2. They'd been around 50-60 years and had gone through extensive combat refinement in WW1 at least. The Germans used them extensively for causing airbursts on the battlefield, both with indirect artillery and direct fire from heavy flak guns. In fact, they had such fuzes for nearly every gun in their inventory, including pre-WW1 ex-naval guns used for coast defense. And German fuzes were extremely reliable with great accuracy of setting--so much so that they didn't even have time markings on them, you just dialed in the time on the fuze setter.

Despite this, however, BTS decided not to include any form of airbursts except for VT fuzes.

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-Bullethead

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[Guest Martin Cracauer]

I remember I read in Allied autobigraphies how surprised they were that Germans used shells that exploded above their foxholes. Apparently they didn't know that it was used in WW1 and before (and of course, the guns were "88s"...).

Anyway, I think the problem with including it in CM is that you had to model the adjusting mechanism. The observer has an additional task to do. You had to have shells explode at the wrong time, then improve timing. Shells falling short must explode nearer to the ground (probably hitting it).

The allied VT arty is modeled quite nicely, IMHO. A number of shells don't work and hit the ground and the effect on troops seems to be wellbalanced as well, including the units price. This can be done without the additional complexity of adjustment.

So I'd say better do VT well instead of doing shrapnell everything half-hearted.

While we are at it: it seems to me that shrapnell of all kind was used less in WW2 than in WW1. That seems odd to me, since soft units were much likely to be mobile in WW2 instead of extremly fortified in WW1. So the effect of shrapnell should have been even bigger in WW2. Anyone knows some numbers and/or reasons?

Martin

[tss]

Martin Cracauer wrote:

Shells falling short must explode nearer to the ground (probably hitting it).

Actually, if all your MT fuzes are airbursts, you are probably aiming too high. When a certain percentage of explosions happen on ground ("nokkare", was (and maybe still is) the technical Finnish term for them), the majority of the shells explode on precisely right altitude. If all bursts are airbursts, the mean burst point is higher than optimal.

- Tommi

[Guest tero]

>Actually, if all your MT fuzes are airbursts, you are probably aiming too high.

Or more precisely your calculation on the shell travel time is slighly off.

>When a certain percentage of explosions happen on ground ("nokkare", was (and maybe still is) the technical Finnish term for them), the majority of the shells explode on precisely right altitude. If all bursts are airbursts, the mean burst point is higher than optimal.

(Important) Note: this applies also to all field artillery with mechanical VT fuses available, not just AA artillery. No radar fuse is required to acheive effective airburst effect.

[This message has been edited by tero (edited 02-27-2001).]

[Bullethead]

Martin Cracauer said:

The allied VT arty is modeled quite nicely, IMHO. A number of shells don't work and hit the ground and the effect on troops seems to be wellbalanced as well, including the units price. This can be done without the additional complexity of adjustment.

The German MT fuzes for arty and IGs were called "Dopp Z" fuzes. They were a combination timed and impact, so if your time of flight calculation erred on the long side, you'd still get the ground burst effect. So knowing this, the Germans would figure things on the long side and back off rather than have their airbursts too high.

Flak guns seemed to have had either impact or time fuzes, but not the combination. OTOH, due to their flat trajectories, flak gun airbursts would have been direct fire so didn't need FOs. Also, if they didn't get an airburst, they probably wouldn't see any misses hitting kilometers away from "overs". So the lack of dual purpose fuzes probably wasn't a problem for them, especially given their range finders. Also, flak guns probably had more time fuzes than any other type given their designed role of shooting down airplanes.

While we are at it: it seems to me that shrapnell of all kind was used less in WW2 than in WW1. That seems odd to me, since soft units were much likely to be mobile in WW2 instead of extremly fortified in WW1.

Shrapnel shells (with all the little balls inside) were developed due to limitations in metalurgical and explosives technology. Basically, metalurgical technology prevented the used of modern-style thin-walled shells because such shells would have broken up in the gun using 1800s metals. So shells had to be pretty thick-walled back then, and the only explosive was black powder. So although explosive shells had existed for centuries by the 1800s, those for field pieces (as opposed to low-velocity mortars) had to be thick-walled, and black powder made them break up into a relatively small number of relatively big chunks--not very effective fragmentation.

So the purpose of the Shrapnel shell was to provide ready-made fragments in the form of musket-sized balls. The charge broke the shell open into the usual big chunks, but the balls filled in the gaps in the fragmentation pattern, leading to higher casualties per shell. This is naturally a rather inefficient method because the balls took up room inside the shell that could have been used for explosive, so the velocity of the balls was low, leading to a relatively small casualty radius. But regardless, Shrapnel was better than just plain explosive shell back then, so remained in use for about 100 years.

But by about 1900, both metalurgical and explosives technologies had advanced to fairly modern standards. This allowed the introduction of thin-walled, high explosive-filled shells. And it was found that when these exploded in the air, the shell casing broke up into tiny splinters traveling at fairly high velocity. IOW, they produced a dense pattern of fragments over a larger area than even contemporary Shrapnel shells. Thus, true Shrapnel shells became obsolete, although they continued in use for lighter guns throughout WW1 due to military conservatism. So today, the word "shrapnel" continues in use as a synonym for fragments, but actual Shrapnel shells were pretty much gone from inventories by the time of WW2.

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-Bullethead

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[tss]

Bullethead wrote:

Shrapnel shells were pretty much gone from inventories by the time of WW2.

The production of shrapnel shells was discontinued after WWI but many countries had still quite large stocks left over and used them also in WWII when regular ammo was on short supply.

Shrapnel shells are also quite effective for close defence of the guns. Set the burn time to minimum and you get a 75 mm shotgun.

- Tommi

[Guest tero]

>Shrapnel shells were pretty much gone from inventories by the time of WW2.

I think the US used beehive rounds during the Vietnam war in their artillery units and at least Sheridan tanks. Shrapnel rounds as a concept are far from extinct.

>Shrapnel shells are also quite effective for close defence of the guns. Set the burn time to minimum and you get a 75 mm shotgun.

Ever seen the movie Gettysburg ? The buckshot scenes are among the most realistic war scenes I have seen.

[Guest Martin Cracauer]

Thank you all for your explanations, especially Bullethead.

Another question (that is somewhat CMBO relevant) is whether airburst shells (shrapnel or not) were less common in WW2 than in WW1. WW1 literature leaves the impression that 30-50% of all shells were airburst, whereas WW2 accounts often meet any airburst with surprise.

Martin

[Bullethead]

tero said:

I think the US used beehive rounds during the Vietnam war in their artillery units and at least Sheridan tanks. Shrapnel rounds as a concept are far from extinct.

The "beehive" round is a totally different concept from that of the Shrapnel shell. The beehive is just the modern form of grapeshot, a big shotgun shell where the little pellets start to disperse at the muzzle. With Shrapnel, there was no dispersion until the shell burst somewhere far downrange.

And as for close defense of guns, just as thin-walled HE is better than Shrapnel for airbursts far downrange, so is it also better for airbursts close to the muzzle. Same technique mentioned--set the fuze time to minimum and work further out with successive rounds.

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-Bullethead

In wine there is wisdom, in beer there is strength, in water there is bacteria.

[Bullethead]

Martin Cracauer said:

Another question (that is somewhat CMBO relevant) is whether airburst shells (shrapnel or not) were less common in WW2 than in WW1. WW1 literature leaves the impression that 30-50% of all shells were airburst, whereas WW2 accounts often meet any airburst with surprise.

I've never gotten the impression that airbursts were rare in WW2. Look at the photos of bombardments going on and you'll see a lot of them. This is because most bombardments try for a mix of airbursts and groundbursts, the former to spray any troops exposed and the latter to break up defensive positions and obstacles. Plus they tend to support each other on troops in the open. Against only airbursts, experienced troops will keep standing up to present a smaller target area to the descending fragments, but this makes them more vulnerable to fragments from groundbursts. So by shooting both at them, they're screwed either way. But anyway, because most bombardments contain a good mix of airbursts, there's no need to mention them specifically--if you say you're being bombarded, you're saying you're getting airbursts because they'er included free of charge

The only times I've read of airbursts coming as a surprise is when troops were exposed to direct fire airbursts from previously unknown flak guns. The shells arrived before the sound of their firing or travel, so all of a sudden, BANG!, an airburst right on you.

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-Bullethead

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[Midnight Warrior]

I read that the allied radar prox fuses were only used over water (i.e from ships) where the spent shell could not easily be retrieved by the enemy as a security precaution to protect the technolgy from falling into axis hands. However, during the battle of the Bulge army AAA units were given the shell for use mainly against ground targets (with great effect) in the thought that by then the war would be over before the Germans could reverse engineer them.

[Guest tero]

>The "beehive" round is a totally different concept from that of the Shrapnel shell.

Not really, deep down. The shrapnel shell basically a long range beehive round. It was developed after all to counter the mass, Napoleonic style infantry attacks at a range.

>The beehive is just the modern form of grapeshot, a big shotgun shell where the little pellets start to disperse at the muzzle. With Shrapnel, there was no dispersion until the shell burst somewhere far downrange.

The operative factor being range to target. Beehive is most definitely a short range munition while shrapnel is a long range munition. But the operating principle (by this I mean how it is intended to kill and maim) is basically the same.

>And as for close defense of guns, just as thin-walled HE is better than Shrapnel for airbursts far downrange, so is it also better for airbursts close to the muzzle. Same technique mentioned--set the fuze time to minimum and work further out with successive rounds.

I thought the beehive round has no fuze. It just exits the muzzle and starts spreading after the casing falls off/disintegrates. Just like a shotgun shot.

[PantherGunner]

As a former Sheridan tanker in the 82nd ABN Div I feel a little qualified to talk about the Sheridan "beehive" round. It is basically a 152mm shotgun shell. The casing is made of a paper/burnable material that totally consumes itself in the firing of the round so there is no casing left after firing. It has small darts as projectiles and not round shot. It was intended to be fired out to a max (and I mean max...not max effective) range of 800 meters. Hope this clears up any confusion about the Sheridan rounds.