rexford

Seeing that Tiger is my favorite tank, I'am always on the look-out for overestimates of Allied weapon effectiveness. Methinks that 6 pdr APCBC from the gun with 793 m/s muzzle velocity may be too powerful. British figures for APCBC penetration of 6 pdr (793 m/s M.V.) are similar to the following (my curvefitting from British Ordnance Board curves may introduce some minor variations here and there): H is homogeneous armor, FH is face-hardened 100m, 107mm H, 112mm FH 250m 103mm H, 108mm FH 500m 96mm H, 102mm FH 1000m 84mm H, 91mm FH 2000m 64mm H, 71mm FH Are the penetration figures in CMAK for 6 pdr APCBC face-hardened or homogeneous penetration? The CMAK figures seem closer to the face-hardened penetration stats although CMAK numbers are a tad higher. It might also be good if the penetration figures for 2 pdr APCBC, 17 pdr APCBC, U.S. 75mm ammo and other important game ammo used by Allies could be identified as homogeneous or face-hardened armor performance.

Rune, what is the source for the quote on 2 pdr AP vs reinforced nose armor on PzKpfw III? Nose armor may be a bad way of saying front hull. Lorrin

Rune, what is the source for the quote on 2 pdr AP vs reinforced nose armor on PzKpfw III? Nose armor may be a bad way of saying front hull. Lorrin

Goodness gracious, another quote that strongly suggests that 2 pdr AP could not penetrate the 32mm/30mm face-hardened combo on PzKpfw IIIH front hulls. What say you JasonC to this???????????!!!!!!!!

Goodness gracious, another quote that strongly suggests that 2 pdr AP could not penetrate the 32mm/30mm face-hardened combo on PzKpfw IIIH front hulls. What say you JasonC to this???????????!!!!!!!!

Found these figures in the orginal Featherstone book Tank Battles in Miniature A wargame's guide to the Western Desert Campaign 1940-1942 AP muzzle velocity of 2,800 fps and armour pentration of 57 at 500 yards at 30 degrees For APCBC introduced in Sept 1941 it is only 2,600 feet per sec with a slightly better pentration 57.5mm at 500 yards at 30 degrees. Most sources list the 2pdr as being supplied with both rounds. Clearly APCBC was an attempt to improve the 2pdrs pentration at least until the 6pdr took over. Featherstone says the round was intoduced after AP was found to break up when hitting German face hardened armour. Does anybody know if APCBC pentration will fall off faster than plain AP at longer ranges than 500 yards becomes of its lower fps? (I understand that the round although lighter is less aerodynamic despite the extra cap meant to make it so?) Debate seems to be breaking down into we are right you are wrong, chaps ! The evidence (yes, it is evidence) presented above as well as the battle reports seems to suggest a marginal chance of pentration at 800 yards on certain tank locations which is not what CMAK is giving - no matter how noble its creators are .

Found these figures in the orginal Featherstone book Tank Battles in Miniature A wargame's guide to the Western Desert Campaign 1940-1942 AP muzzle velocity of 2,800 fps and armour pentration of 57 at 500 yards at 30 degrees For APCBC introduced in Sept 1941 it is only 2,600 feet per sec with a slightly better pentration 57.5mm at 500 yards at 30 degrees. Most sources list the 2pdr as being supplied with both rounds. Clearly APCBC was an attempt to improve the 2pdrs pentration at least until the 6pdr took over. Featherstone says the round was intoduced after AP was found to break up when hitting German face hardened armour. Does anybody know if APCBC pentration will fall off faster than plain AP at longer ranges than 500 yards becomes of its lower fps? (I understand that the round although lighter is less aerodynamic despite the extra cap meant to make it so?) Debate seems to be breaking down into we are right you are wrong, chaps ! The evidence (yes, it is evidence) presented above as well as the battle reports seems to suggest a marginal chance of pentration at 800 yards on certain tank locations which is not what CMAK is giving - no matter how noble its creators are .

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>

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>

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.

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.

"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).

"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).

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.

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.

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.

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.

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>

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>

The holes in the Tiger tank rear hull armor must be how that Stuart managed to knock out a Tiger from the rear. There are several references to how tanks should aim at the thinner armor on the Tiger rear hull, and the guidance may have been lead to assume an incorrect fact (rear armor thickness actually equals the side armor thickness) because of some lucky penetrations through the hole areas.

Bastables is right on the mark. The 32mm/30mm face-hardened combo on the front hull of PzKpfw IIIH caused 2 pdr AP hits to shatter at 200 yards during British tests in Cairo (May 1942). The upper area of the gun mantlet on PzKpfw IIIH is 35mm face-hardened angled at about 38 degrees from vertical, which resists 2 pdr hits like about 52mm vertical. 2 pdr AP penetrates 51mm face-hardened at 500 yards, so I would guess that the 2 pdr successes were occurring against the mantlet. There is a current question regarding whether the Cairo tests were with 0 degree side angle or 30 degrees. The report doesn't say which angle. If a 30 degree side angle was used at Cairo, the effective resistance of the 32mm/30mm driver plate on PzKpfw IIIH would be about 59mm. Does the Battleaxe report say anything about where the 500 yard penetrations by 2 pdr were occurring, or indicate or suggest that the hull front was vulnerable at 500 yards to 2 pdr hits?

Bastables is right on the mark. The 32mm/30mm face-hardened combo on the front hull of PzKpfw IIIH caused 2 pdr AP hits to shatter at 200 yards during British tests in Cairo (May 1942). The upper area of the gun mantlet on PzKpfw IIIH is 35mm face-hardened angled at about 38 degrees from vertical, which resists 2 pdr hits like about 52mm vertical. 2 pdr AP penetrates 51mm face-hardened at 500 yards, so I would guess that the 2 pdr successes were occurring against the mantlet. There is a current question regarding whether the Cairo tests were with 0 degree side angle or 30 degrees. The report doesn't say which angle. If a 30 degree side angle was used at Cairo, the effective resistance of the 32mm/30mm driver plate on PzKpfw IIIH would be about 59mm. Does the Battleaxe report say anything about where the 500 yard penetrations by 2 pdr were occurring, or indicate or suggest that the hull front was vulnerable at 500 yards to 2 pdr hits?

The Panther 75L70 fired a 6.8 kg round at 935 m/s, the PzKpfw IVH 75L48 fired the same weight round at 750 m/s. Using a ballistic trajectory program the 1000m velocity for each round is estimated to be: At 1000m Range ============== 75L48, 634 m/s, 84.5% of muzzle velocity, 1.45 seconds. velocity drops 116 m/s within 1000m 75L70, 803 m/s, 85.9% of muzzle velocity, 1.15 seconds, velocity drops 132 m/s within 1000m The faster round loses a lower percentage of its initial velocity from gun to 1000m. Strange looking result at first glance. But it really isn't that strange a result. The velocity loss per second is proportional to the velocity squared times the drag factor, and higher velocity rounds have a smaller drag coefficient. So the Panther 75mm loses more velocity per second than the PzKpfw IVH, but less than the velocity squared term would suggest. But, and this is the key, higher velocity rounds also travel a greater distance per second, so the bottom line is that the Panther 75mm round retains a higher percentage of its initial velocity at 1000m compared to 75L48. The Panther 75mm trajectory is much flatter than the Pzkpfw IVH 75mm, so a Panther crew will hit more often than the PzKpfw IVH for the same range estimation error. In addition, the Panther 75mm had a much smaller constant aim random error than the 75L48, which also contributed to better accuracy. The Tiger 88L56 had one of the smallest constant aim random errors of any WW II gun, which helped to improve on the accuracy which would obtained from a none too high 780 m/s muzzle velocity. [ November 29, 2003, 09:24 PM: Message edited by: rexford ]

The following summarizes everything that was found on T34 armor thickness, quality and resistance to German 75mm hits, using much information posted by others on this thread: NOTES ON PzKpfw IV 75mm L43 GUN AGAINST T34 1. On 26 May 1942 the General der Schnellen Truppen beim Oberkommando des Heeres distributed the following "Instructions to units on the Eastern Front for Combating the Russian T-34 Tank with our Panzers": "Characteristics of the T34. The T-34 is faster, more maneuverable, has better cross-country mobility than our Pz.Kpfw.lll and IV. Its armor is stronger. The penetrating ability of its 7.62 cm cannon is superior to our 5 cm KwK. and the 7.5 cm KwK40. The favorable form of sloping all of the armor plates aids in causing the shells to skid off. The T-34 can be penetrated at ranges up to 1000 metres with the 7.5 cm PaK 40 as well as the 7.5 cm Hohlgranate (hollow-charge shells)" My notes: ======= Comments regarding sloping of armor leading to shells to skid off and 1000m penetration range by Pak 40 suggests German guns may have been firing with poor angles to target, leading to highly angled hits against the front and side armor. Interesting to note that Russian cross-country races with Russian and captured German tanks showed PzKpfw III to be superior to early T34 and comparable to later T34 models, which is contrary to above statements. It sounds like the Germans were beat bad by the Russians and the report is using excuses to cover up possibly poor tactics. Based on my calculations 75mm Pak 40 APCBC penetrates about +10% more than 75mm L43 at all ranges, so 75L43 would penetrate T34 front at less than 1000m. 2. Jentz Vol 1 243 Pz regt 33 "Penetration Ability of the 7,5cm Kw.K 40 L.43 Pzgr 39 against the T-34 (31 July 1943) The T34 is cleanly penetrated at every angle that it is hit at ranges up to 1200m." The report also notes that the advent of the 5cm and 7,5cm lang has meant a definite superiority to the T34. 3. Page 41 in the English edition of Jentz, where it explicitly states in a report from 5.PD, dated 20. March 1943: " 7,5cm Kw.K. L/43 in 4 Pz.Kpfw.IV [Knocked out] 17 KW-I, 26 T34, 1 T26, 1 Mark II, 3 Mark III, 1 General Lee Pzgr.39 was fired at ranges from 1200 to 1600 meters. Every hit caused a destructive effect with the tank going up in flames. Two to three Pzgr.39 were expended per tank killed." 4. Jentz says on pages 36 and 37 in Vol. 2 "In the period from 7 March to 20 March 1943, 250 T34, 16 T60 or T70 and 3 KW-1 tanks were knocked out. The number of kills scored by each type of weapon were: * 188 by Pz.Kpfw.IV 7,5cm lang * 41 by Sturmgeschuetz 7,5cm lang * 30 by Pz.Kpfw.VI (Tiger) * 4 by 7,5cm Pak (mot Zug) * 4 by 7,5cm Pak (Sfl) * 1 by a direct hit from a sIG * 1 using a Hafthohlladung (PR GD began with 5 Pz II, 20 Pz III 50L60, 10 Pz IV 75L24, 75 Pz IV 75L43, 9 Pz VI 88L56, 2 PzBefWg 50L42, and 26 Flammpanzer III. Their losses and total write offs amounted to 1 Pz III 50L60, 1 Pz IV 75L24, 11 Pz IV 75L43 and 1 Pz VI Tiger). Degradation of the Russian armour steel was not noticeable. However, the armor steel is darker and finished rougher. The tanks reveal they were produced in a short time, because there is no evidence of any close tolerance work. The turret of the T34 is not made form a single piece, instead it is assembled from numerous pieces. In many T34 tanks the armor walls wre created from pieces of 1cm thick steel with 6cm filling of cast iron or other material and then a second piece of 1cm thick steel." 5. Forum discussion of Russian firing test report by Valera Potapov where 75L43 penetrates T34 front hull at 1000m with 30 degree side angle. 6. George Forty presentation of report from U.S. Department of the Army pamphlet No. 20-233 entitled German Defense Tactics against Russian Breakthroughs, published October 1951. "Normally the Russian tanks would stand in ambush at the hitherto safe distance of 1,350 yards (1,235m) and wait for the German tanks to expose themselves upon their exit from a village. They would then take on the German tanks under fire while the panzers were still outranged." Since PzKpfw IV with 75L43 guns were in the area, the above suggests that T34 front hull was proof against 75L43 hits at 1,235m. Reported combat results in 34 T34 kills by two Tigers. 7. Jeff Duquette measures T34 glacis thickness through opened hatch door, 50mm to 55mm range (supporting picture posted on Yahoo! Tankers site). 8. When Germans duplicate T34 armor for spring 1942 firing tests, they use plates with 42mm to 53mm thickness which suggests the possibility that a wide range of field measurements were experienced although it is not conclusive evidence. 9. Americans measure actual thickness of SU 100 lower front hull as 60mm although design spec is 45mm. 10. Americans analyze 45mm armor plates from T34/85's found in Berlin ruins, plates measure close to 45mm but vary in quality from excellent to poor. Firing tests compared resistance of Russian high hardness armor to American medium hardness plate, 45mm Russian high hardness armor is inferior to U.S. medium hardness.

Medium hardness plate, 220 to 300 Brinell Hardness, is designed to have good ductility so it can take hard hits without cracking. Shermans used medium hardness armor. High hardness armor, 450 Brinell, has low impact resistance than good medium hardness plate. A 45mm medium hardness plate will resist like 45mm of medium hardness armor against 20mm and 90mm hits. A 45mm high hardness plate may resist 20mm hits like 53mm of medium hardness plate, but will resist 75mm hits like about 34mm medium hardness because it cannot take the impact with cracking. Russian tankers talk alot about how ricochets off the T34 could result in armor flakes flying off the armor interior, injuring or killing the crew. It's due to the brittle nature of the plate. Russian tankers who fought in Shermans noted that ricochets did not result in internal armor flaking, like the T34, because the plate was medium hardness and had high impact resistance. High hardness armor is like auto glass, it works really well against small objects but can't take large hits very well and when it is penetrated it can send shards flying off into the driver compartment. The good thing about high hardness armor is that it can be quicker to make than medium hardness armor, because one doesn't have to spend as much time reducing the hardness to a specific range and getting the correct temper that will assure high impact resistance. So high hardness armor may have allowed more T34 to be made, although they were not especially resistant to PzKpfw IV and StuG III 75mm hits. Prior to October 1943, the Americans made quite a bit of medium hardness cast armor that was very brittle due to the composition and heat treatment. German face-hardened armor uses a thin 500 to 600 Brinell hardness surface layer to break up the nose of projectiles, but the bulk of the armor thickness is around 350 Brinell Hardness area and provides good impact resistance. Face-hardened and high hardness armor is good when you have thin plates under attack by small rounds, and you wish to boost the resistance. Like an armored car or halftrack attacked by rifle or machine gun bullets. U-Boats supposedly had face-hardened conning tower walls to boost the resistance to 20mm aircraft cannon fire. The Russians noted during the Spanish Civil War that penetrations of the German tanks with high hardness Krupp armor usually resulted in severe crew casualties as the armor shattered and allowed pieces to fly inside the tank. Russian T26 tanks used medium hardness armor and unless a round directly hit a crew man it was common to suffer penetration without crew injury. [ November 28, 2003, 04:33 PM: Message edited by: rexford ]