Uber Artillery

[rickier65]

ORIGINAL: sztartur

I suggest this to be included in the update too. 

Artur,

We're probably going to incorporate a slightly revised version of this into the patch as a short term solution to the off-map artillery issue. The version we're looking at will include data for some other guns that may be added at a future date as well as the lower penetration values you suggested.

thanks for your input on this.

Rick

[Lieste]

No, I've nothing to do with WOT. (couldn't run it on this box even if I wanted fantasy tanks... and MMO play)

Currently on the Panther (BFTB) beta team.

Those numbers look a touch higher than I'd expect, but that is only a gut feeling/recollection from memory - I do intend to compare to my collected data once I've got time.

[Mobius]

ORIGINAL: Lieste
Those numbers look a touch higher than I'd expect, but that is only a gut feeling/recollection from memory - I do intend to compare to my collected data once I've got time.

We don't use those actual numbers as the tabular data but with the variable penetration table modifiers they can be obtained on occasion.

[Lieste]

Ok, I've had a few moments to compare to data from Office of Ordnance Officers Terminal Data Vol III, Part 4, p49.

Extrapolating breach thickness of armour of the GP bomb (instant fuse, no deformation (ie blast alone)*)...

pen thickness in mm ~ 15.64 * (HE kg) ^ 0.3321

This gives HE weight similar to the 75mm being 'good' for around 14mm of RHA, with the 155mm only at 30mm, 8" How @ 37mm. It is possible that ~20% more could be expected based on 'tail fuse, instantaneous' note given in the data.

There is considerable KE/Impulse involved in short range impacts, and KE fragmentation impacts... this is probably sufficient to destroy most vehicles when looking at 6"+ weapons, but has little to do with HE effect... I remain unsure how 'strong' HE blast can be if larger bombs are less capable...

*For GP bombs the impact will cause low order deflagration, or break-up at much less than the thickness the blast will rupture, if the fuse is set to delay. SAP has lower perforation for a given HE weight, but equal perforation with intact function of delay fuse as the breach caused by instant fuse, and AP performs better in direct impacts (up to ~8" armour without deformation), but has worse blast capability per HE weight which is also lower. It can be assumed (IMO) that similar relationships will be seen for shell... as shell is relatively thicker walled than bomb, the above range of perforations may be optimistic?

Interested in your response.

[Mobius]

ORIGINAL: Lieste
Interested in your response.

Those numbers are reasonable for a through and through holing of the plate.
Maybe you can find some examples of ship's decks that were hit by Common shells of 6" or 8" and the damage done to verify things.

We know that a 150mm HE hit a Pershing on the roof of the turret blowing the cupola and hatch off. Another hit next to the track destroying it and setting the Pershing on fire.
The Parola Museum in Finland has a T-55 turret that has a hit by 100mm HE on 64mm of armor that made a crack on the inside. Upper nit #5. Lower hit #5 is from 57mm HE.




There is a lot of variation in the HE blast affect. And that affect enclosed spaces like in tanks.

[sztartur2]

ORIGINAL: Rick

ORIGINAL: sztartur

I suggest this to be included in the update too. 

Artur,

We're probably going to incorporate a slightly revised version of this into the patch as a short term solution to the off-map artillery issue. The version we're looking at will include data for some other guns that may be added at a future date as well as the lower penetration values you suggested.

thanks for your input on this.

Rick

Thank you for considering it.

[Lieste]

We know nothing about the impact conditions of the HE hit there. Judging solely on the absence of extensive fragmentation scarring, I'd take a WAG at moderate range/high velocity, with a deformed/low order detonation.

Compare to the pattern in/around the 57mm impact area.

If this is the case, then you're possibly looking at the results of (mostly) a 12kg steel body impacting (and being stopped rapidly) at around 500-600m/s - that is a fair amount of impulse to deal with, and ~60% calibre for cracking doesn't seem unreasonable. (Impulse is actually worse from a non-penetrating/poor penetrating round than it is for one that travels a fair way, as the transfer of momentum is more abrupt). Momentum transfer rates on absorbed impact of a typical projectile is around 4x that experienced in recoil from the weapon firing it - this is reduced if the round deflects along the plate face of a sloped armour, rather than stops, but increased if it 'bounces' on a normal plate with the round intact - the assumption is that the round 'splashes' as a small-arms round does without significant penetration.