Proximity Fuses

[hammurabi70]

Do the rules reflect the change in performance of artillery with the introduction of Proximity Fuses?  Do any rules?

[Lord Kermit of Birkenhead]

Not aware of any that do. The fuze does make HE somewhat more effective and will increase ROF as no need to set fuse time. Noty however much use agaist enclosed armour, as its an airburst round.

[Big Insect]

Nope. Too granular detail for BKC.
I'm not sure any rules sets cover this. But others might know different.
Cheers
Mark

[sultanbev]

Do the rules reflect the change in performance of artillery with the introduction of Proximity Fuses?  Do any rules?

My own do, a die roll of 1-3 to hit becomes 1-4, the die type varying with circumstance from 1D6 for a squad moving in the open to 1D20 suppressed in cover. But no gamer uses them much. Mainly because airburst ammo doesn't damage armour or anti-tank guns. For WW2 it is only really a thing from December 1944 for a limited number of American gun types I think.

At the level of BKC and CWC, it shouldn't really factor into it.

[hammurabi70]

At the level of BKC and CWC, it shouldn't really factor into it.

It would seem that from their deployment at the Battle of the Bulge they provided a step improvement in artillery performance.  It might be a tactical effect but had widespread serious implications.  People talk of quadruple or quintuple performance improvement.  As a significant technological change one would have thought it ought to be represented.  At least the +1 enhances the result!

[Lord Kermit of Birkenhead]

What they did was speed up  response and give more accurate airburst. SA mark said not appropriate to BKC as too low level. I suspect the same with Battlegroup. Certainly not usable with Rapid Fire.

[sultanbev]

They weren't that common. I am sure there are actual numbers out there, but I did find this thread:
https://ww2f.com/threads/pozit-fuse.74760/

"From 1 January to 8 February 1945, 10.9% of 75mm and 105mm howitzer HE expended was with the T80 POZIT fuze and 10.9% of 155mm, 8", and 240mm howitzer HE was expended was with the T76 POZIT fuze. As of 8 February, 17.5% of 75mm and 105mm howitzer HE was available with T80 and 7.6% of 155mm, 8", and 240mm howitzer HE was available with T76."

There might have been more but not used.
"The fuses did have some limitations. You couldn't fire them if they were going to pass through rain, hail or snow storms. Nor were they to be used if there was any chance of the rounds trajectory came anywhere near friendly forces. Like time fuses, they were useless if the enemy was under a tree canopy; the rounds would go off 60ft. above the tree tops and the trees themselves would soak up the splinters. It was better to shoot contact fuses into the tree tops above the enemy positions."

There is an interesting article here on the development of naval HE-VT shells:
https://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/r/radio-proximty-vt-fuzes.html

Another thread on reddit says they had a 50% dud rate due to the batteries
https://www.quora.com/Did-the-Axis-forces-capture-VT-proximity-fuzed-shells-during-World-War-2

As the bulk of the weather and terrain in the Ardennes was rain, snow and forest, I suspect it's increased effective was a perception based on the occasions they caught German infantry in the open, which as they were attacking most of that time kinda makes sense.

Looking at the data above, only 1 in 6 75-105mm shells were HE-VT, (1 in 14 for bigger calibres) and only 1 in 10 salvos used them, so for BKC purposes you might buy them as special munitions, with a +1D6 per normal 4D6 hit against troops in the open or with no overhead cover but no or 1D6 against AFVs & guns, and no or 1D6 against troops in woods or in trenches with overhead cover. And that is from December 1944 onwards only, for US 75mm pack howitzers, 90mm AA, 105mm howitzers, 155mm howitzers, 8" howitzers and 240mm guns. That's a lot of rule for a very small application, but go for it if you wish.

[hammurabi70]

There might have been more but not used.
"The fuses did have some limitations. You couldn't fire them if they were going to pass through rain, hail or snow storms. Nor were they to be used if there was any chance of the rounds trajectory came anywhere near friendly forces. Like time fuses, they were useless if the enemy was under a tree canopy; the rounds would go off 60ft. above the tree tops and the trees themselves would soak up the splinters. It was better to shoot contact fuses into the tree tops above the enemy positions."

My understanding was that there were devastating against troops in trees, which provided no cover but enhanced the splintering effects; a game changer in their impact on tactics. That's statistics for you.

Proximity Fuses

[Lord Kermit of Birkenhead]

My understanding was that there were devastating against troops in trees, which provided no cover but enhanced the splintering effects; a game changer in their impact on tactics. That's statistics for you.

Proximity Fuses

True about tree bursts but the same occured with airburst timers and graze fuses. This is why you dont fire mortars in woods, the graze fuse is armed as it leaves the barrel and hitting a leaf can set the round off.