Looking to discuss 2pdr effectiveness in RL and CMAK

[rune]

For a quite interesting take on this, read this:

http://www.nzetc.org/etexts/WH2Tobr/c5.html

Page 59.

Rune

[rune]

For a quite interesting take on this, read this:

http://www.nzetc.org/etexts/WH2Tobr/c5.html

Page 59.

Rune

[rexford]

Originally posted by Bastables:

</font><blockquote>quote:</font><hr />Originally posted by The Green Rascal:

Table 4.1.2 extrapolated from firing test "carried out" by Lt.Col Drew and Col Jarrett show the PIIIH at a 30deg side angle was invunerable to 2pdr strikes on the front Superstructure and Hull armour. Turret could be perforated at 800yds 30deg side angle and Mantlet was perforated at 200yds 30 deg side angle.

You're probably hitting the "turret" with no oblique/side angle. </font>

[rexford]

Originally posted by Bastables:

</font><blockquote>quote:</font><hr />Originally posted by The Green Rascal:

Table 4.1.2 extrapolated from firing test "carried out" by Lt.Col Drew and Col Jarrett show the PIIIH at a 30deg side angle was invunerable to 2pdr strikes on the front Superstructure and Hull armour. Turret could be perforated at 800yds 30deg side angle and Mantlet was perforated at 200yds 30 deg side angle.

You're probably hitting the "turret" with no oblique/side angle. </font>

[rexford]

Originally posted by The Green Rascal:

So far Bastables has said that PZIIIH front turrets could be perforated at 800m and supplied that report (thanks!), as against Barrie Pitt's assertions and Rexford who both seem to be saying in different ways that 500m is the limit of effective range. I'm still hoping for some further comments.

If Bastables report is the ulimate deciding factor and we accept PZIIIs were destroyed at 800m frontally by 2pdrs, then it is definitely not in agreement with Pitt at the very least.

500 yards should be about it for 2 pdr AP against top of PzKpw III gun mantlet, but bottom half is only angled at 20 degrees or so which should be defeated beyond 1000 yards.

[rexford]

Originally posted by The Green Rascal:

So far Bastables has said that PZIIIH front turrets could be perforated at 800m and supplied that report (thanks!), as against Barrie Pitt's assertions and Rexford who both seem to be saying in different ways that 500m is the limit of effective range. I'm still hoping for some further comments.

If Bastables report is the ulimate deciding factor and we accept PZIIIs were destroyed at 800m frontally by 2pdrs, then it is definitely not in agreement with Pitt at the very least.

500 yards should be about it for 2 pdr AP against top of PzKpw III gun mantlet, but bottom half is only angled at 20 degrees or so which should be defeated beyond 1000 yards.

[rexford]

Originally posted by MikeyD:

I just checked the game and the 2 pdr is said to penetrate 76mm@zero degrees/59mm@30 degrees from 500m out.

Rexford, on the other hand, pegs 2 pdr penetration from 500m at just 51mm at zero degrees, significantly below the game's specs.

I'm reminded of our old debate over IS-2 frontal armor in CMBB. The problem there turned out to be duelling "reliable" data tables. I wonder if CM is working off a 59mm@30 degree assumption when it should instead have been read as from zero degrees?

CMAK shows the 2 pdr AP penetration against homogeneous armor, while the face-hardened stats are much lower. They used the face-hardened figures when the armor was face-hardened.

[rexford]

Originally posted by MikeyD:

I just checked the game and the 2 pdr is said to penetrate 76mm@zero degrees/59mm@30 degrees from 500m out.

Rexford, on the other hand, pegs 2 pdr penetration from 500m at just 51mm at zero degrees, significantly below the game's specs.

I'm reminded of our old debate over IS-2 frontal armor in CMBB. The problem there turned out to be duelling "reliable" data tables. I wonder if CM is working off a 59mm@30 degree assumption when it should instead have been read as from zero degrees?

CMAK shows the 2 pdr AP penetration against homogeneous armor, while the face-hardened stats are much lower. They used the face-hardened figures when the armor was face-hardened.

[Wisbech_lad]

Also, 2pdr is solid shot (no HE burster)

It could be that at 800 yards plus, it could penetrate, but the tank crews just didn't know it? They didn't have "detailed armour hits" on!

[Wisbech_lad]

Also, 2pdr is solid shot (no HE burster)

It could be that at 800 yards plus, it could penetrate, but the tank crews just didn't know it? They didn't have "detailed armour hits" on!

[rexford]

Originally posted by rune:

For a quite interesting take on this, read this:

http://www.nzetc.org/etexts/WH2Tobr/c5.html

Page 59.

Rune

"To complicate the picture, a few Pzkw IIIs were fitted with reinforcing plates which made them almost invulnerable to the 2-pounder except on the sides and these encouraged the myth that the British tanks were outgunned."

"Almost invulnerable" to me suggests that a few front areas might be defeated, such as the mantlet bottom, but the majority of the armor on the front would be safe.

This is consistent with the Cairo tests if the trials were carried out with the guns aiming directly at the hull front without side angle (gun barrel in line with hull facing).

[rexford]

Originally posted by rune:

For a quite interesting take on this, read this:

http://www.nzetc.org/etexts/WH2Tobr/c5.html

Page 59.

Rune

"To complicate the picture, a few Pzkw IIIs were fitted with reinforcing plates which made them almost invulnerable to the 2-pounder except on the sides and these encouraged the myth that the British tanks were outgunned."

"Almost invulnerable" to me suggests that a few front areas might be defeated, such as the mantlet bottom, but the majority of the armor on the front would be safe.

This is consistent with the Cairo tests if the trials were carried out with the guns aiming directly at the hull front without side angle (gun barrel in line with hull facing).

[James Crowley]

Originally posted by rexford:

</font><blockquote>quote:</font><hr />Originally posted by Bastables:

</font><blockquote>quote:</font><hr />Originally posted by The Green Rascal:

Table 4.1.2 extrapolated from firing test "carried out" by Lt.Col Drew and Col Jarrett show the PIIIH at a 30deg side angle was invunerable to 2pdr strikes on the front Superstructure and Hull armour. Turret could be perforated at 800yds 30deg side angle and Mantlet was perforated at 200yds 30 deg side angle.

You're probably hitting the "turret" with no oblique/side angle. </font>

[James Crowley]

Originally posted by rexford:

</font><blockquote>quote:</font><hr />Originally posted by Bastables:

</font><blockquote>quote:</font><hr />Originally posted by The Green Rascal:

Table 4.1.2 extrapolated from firing test "carried out" by Lt.Col Drew and Col Jarrett show the PIIIH at a 30deg side angle was invunerable to 2pdr strikes on the front Superstructure and Hull armour. Turret could be perforated at 800yds 30deg side angle and Mantlet was perforated at 200yds 30 deg side angle.

You're probably hitting the "turret" with no oblique/side angle. </font>

[Mark Gallear]

Very impressed with the discussion - which apart from Rexford who says AP - does not say which ammo type the figures you give refer to. I assume at this date only AP was available. Is AP, APHV, APCBC and APCNR with and without the Littlejohn Mk II adaptor fitted modelled in CMAK? Do the diffrent marks of 2pdr sometimes made to relaxed tolerances make any difference?

I was impressed by Runes links although I have seen them before. The RA site which mentions a HE round complete with fuse number - has had me mystified in the past! WWII vehicles com is brilliant all power to it ! Strangely the site gives figures for the Littlejohn with the 6 pdr - I thought it was only tested on this gun?

(Is the Green Rascal any relation to Bruce Lee - the Green Hornet? )

[Mark Gallear]

Very impressed with the discussion - which apart from Rexford who says AP - does not say which ammo type the figures you give refer to. I assume at this date only AP was available. Is AP, APHV, APCBC and APCNR with and without the Littlejohn Mk II adaptor fitted modelled in CMAK? Do the diffrent marks of 2pdr sometimes made to relaxed tolerances make any difference?

I was impressed by Runes links although I have seen them before. The RA site which mentions a HE round complete with fuse number - has had me mystified in the past! WWII vehicles com is brilliant all power to it ! Strangely the site gives figures for the Littlejohn with the 6 pdr - I thought it was only tested on this gun?

(Is the Green Rascal any relation to Bruce Lee - the Green Hornet? )

[MikeyD]

Ooops! My earlier quote of 76mm at 30 degrees/500m for the 2 pdr turned out to be late war APCBC shot. My goof

[MikeyD]

Ooops! My earlier quote of 76mm at 30 degrees/500m for the 2 pdr turned out to be late war APCBC shot. My goof

[The Green Rascal]

Again many thanks to everyone helping out here. If anyone is still in doubt may I reiterate that we have now proved with many sources that CMAKs 2pdr penetration figures are absolutely right on the mark.

Regarding the PzIII turret front, I re-ran the test a few times tonight and made the effort of noting down the results of hits all of which occurred between 1000-1100m. An interesting indication of what followed was a 2pdr's chances of killing PZIIIs at 1000m plus, which according to the LOS tool were 'FAIR'.

I noted 43 hits on the turret front of the PZIIIs at @1000m. 9 were ricochets, 10 were partial penetrations, 22 were penetrations, 2 were penetrations at weak points and 1 was a gun hit. Percentage wise it works out as follows:

Penetrations..........................50%

Partial Penetrations................23%

Ricochets...............................20%

Penetrations at weak points.....5%

Gun hits................................2%

Our evidence so far suggests that if a PZIII could be killed over 500m it would probably require a hit on the lower gun mantlet. I put forward the above figures to advise that in CMAK around 80% of turret hits by 2pdrs hitting over 1000m range get through to some degree, and 55% are very bad news indeed. Ricochets are in a small minority. Can we square this with our sources or with the physical makeup of a PZIII turret front?

[ December 05, 2003, 07:01 PM: Message edited by: The Green Rascal ]

[The Green Rascal]

Again many thanks to everyone helping out here. If anyone is still in doubt may I reiterate that we have now proved with many sources that CMAKs 2pdr penetration figures are absolutely right on the mark.

Regarding the PzIII turret front, I re-ran the test a few times tonight and made the effort of noting down the results of hits all of which occurred between 1000-1100m. An interesting indication of what followed was a 2pdr's chances of killing PZIIIs at 1000m plus, which according to the LOS tool were 'FAIR'.

I noted 43 hits on the turret front of the PZIIIs at @1000m. 9 were ricochets, 10 were partial penetrations, 22 were penetrations, 2 were penetrations at weak points and 1 was a gun hit. Percentage wise it works out as follows:

Penetrations..........................50%

Partial Penetrations................23%

Ricochets...............................20%

Penetrations at weak points.....5%

Gun hits................................2%

Our evidence so far suggests that if a PZIII could be killed over 500m it would probably require a hit on the lower gun mantlet. I put forward the above figures to advise that in CMAK around 80% of turret hits by 2pdrs hitting over 1000m range get through to some degree, and 55% are very bad news indeed. Ricochets are in a small minority. Can we square this with our sources or with the physical makeup of a PZIII turret front?

[ December 05, 2003, 07:01 PM: Message edited by: The Green Rascal ]

[Mark Gallear]

This is what Stuart Hamilton, tank and later squadron commander in 8th Royal Tank Regiment in his book “Armoured Odyssey” says on this issue. He is taking about the Valentine in June 1941. It was unfortunately armed with a piddling little 2–pounder pop gun and a Besa machinegun. The 2 –pdr had been effective in close quarter fighting as in 1940 in France but now, 18 months later, on the flat, wide, open desert well, frankly, it was bloody useless because the German Panzer Mark III with its 50mm and the Panzer IV with its 75 mm could out-gun us all the time, being able to knock us out at 900/1000 yards range, let alone the 88mms at 300 yards. As we could only knock them out at about 400/500 yards it was really like being a lightweight in the ring with a heavyweight. The German tanks also had five man crews and they were faster than ours as they could do about 20-25 mph, whereas we could only manage 15-20 mph. The only thing that was in our favour was that our armour was thicker, and as we were diesel tanks and not petrol we did not brew up as quickly when hit.

Green Rascal results do not for me fit in with Hamilton's perceptions as to what his tank could do.

However, we are not really comparing like with like – Green Rascals figures are for penetrations, Hamilton’s, and others perceptions are for knockouts. If a high percentage of these penetrations convert into knockouts then I think something is going wrong. I don’t have the game yet to test.

Still would like to see a greater discussion on the other rounds used and effectiveness as well as AP.

[ December 06, 2003, 07:34 AM: Message edited by: Mark Gallear ]

[Mark Gallear]

This is what Stuart Hamilton, tank and later squadron commander in 8th Royal Tank Regiment in his book “Armoured Odyssey” says on this issue. He is taking about the Valentine in June 1941. It was unfortunately armed with a piddling little 2–pounder pop gun and a Besa machinegun. The 2 –pdr had been effective in close quarter fighting as in 1940 in France but now, 18 months later, on the flat, wide, open desert well, frankly, it was bloody useless because the German Panzer Mark III with its 50mm and the Panzer IV with its 75 mm could out-gun us all the time, being able to knock us out at 900/1000 yards range, let alone the 88mms at 300 yards. As we could only knock them out at about 400/500 yards it was really like being a lightweight in the ring with a heavyweight. The German tanks also had five man crews and they were faster than ours as they could do about 20-25 mph, whereas we could only manage 15-20 mph. The only thing that was in our favour was that our armour was thicker, and as we were diesel tanks and not petrol we did not brew up as quickly when hit.

Green Rascal results do not for me fit in with Hamilton's perceptions as to what his tank could do.

However, we are not really comparing like with like – Green Rascals figures are for penetrations, Hamilton’s, and others perceptions are for knockouts. If a high percentage of these penetrations convert into knockouts then I think something is going wrong. I don’t have the game yet to test.

Still would like to see a greater discussion on the other rounds used and effectiveness as well as AP.

[ December 06, 2003, 07:34 AM: Message edited by: Mark Gallear ]

[The Green Rascal]

Thanks Mark, another historical article to go into the 'ineffective' camp.

It is difficult for me to see exactly how many penetrations are resulting in knockouts because of the death clock and all the 2pdr shots hitting the turret fronts in rapid sucession. The best time for me to see it is when the test starts and the first hits go in. Although this doesn't give me as big a sample, it seems that around 40-50% of penetrations result in knockouts, 10-20% crew casualties, 30-40% have no effect. Even 'partial penetrations' can result in knockouts.

I think the best way of surmising how likely it is that a penetration will result in a knockout of the PZIII at 1000m is by using what the LOS tool says - i.e. FAIR. And as we have seen above, there is a massive 80% chance that any hit will penetrate the turret front.

It doesn't make sense, and is giving us a very different simulation to what we might expect from reading history. Sorry BFC, but I am now thinking we have a problem which needs addressing if you wish to produce a reasonable facsimile of desert tank warfare in 1941-1942.

[Edit] A simple solution which occurs, and would work with our sources, would be to multiply the resistance to hits of curved armour by 1.75 + (random number between -0.75 and 0.75).

This would give a PZIII turret front an average resistance to 2pdrs at 500m at 52mm as per the Cairo tests, and make it apparent why so many say that was the limit of effective 2pdr range. The random number would also allow for hits on the lower mantlet at further ranges.

[ December 06, 2003, 09:07 AM: Message edited by: The Green Rascal ]

[The Green Rascal]

Thanks Mark, another historical article to go into the 'ineffective' camp.

It is difficult for me to see exactly how many penetrations are resulting in knockouts because of the death clock and all the 2pdr shots hitting the turret fronts in rapid sucession. The best time for me to see it is when the test starts and the first hits go in. Although this doesn't give me as big a sample, it seems that around 40-50% of penetrations result in knockouts, 10-20% crew casualties, 30-40% have no effect. Even 'partial penetrations' can result in knockouts.

I think the best way of surmising how likely it is that a penetration will result in a knockout of the PZIII at 1000m is by using what the LOS tool says - i.e. FAIR. And as we have seen above, there is a massive 80% chance that any hit will penetrate the turret front.

It doesn't make sense, and is giving us a very different simulation to what we might expect from reading history. Sorry BFC, but I am now thinking we have a problem which needs addressing if you wish to produce a reasonable facsimile of desert tank warfare in 1941-1942.

[Edit] A simple solution which occurs, and would work with our sources, would be to multiply the resistance to hits of curved armour by 1.75 + (random number between -0.75 and 0.75).

This would give a PZIII turret front an average resistance to 2pdrs at 500m at 52mm as per the Cairo tests, and make it apparent why so many say that was the limit of effective 2pdr range. The random number would also allow for hits on the lower mantlet at further ranges.

[ December 06, 2003, 09:07 AM: Message edited by: The Green Rascal ]

[rexford]

If the bottom half of the PzKpfw III mantlet is the vulnerable area, it will be hit much more often than the veyr resistant top area.

Guns generally aim at the center of mass of a target, which would be the PzKpfw III driver plate. The shots are the distributed in a bell shaped curve about the aim point, so more shots land on the mantlet bottom than top because the bottom is closer to the aim point.

In other words, due to shot scatter the vulnerable bottom area would be hit more often than the upper mantlet.