WineCape Posted June 22, 2002 Share Posted June 22, 2002 I have noticed that the US M4 Sherman range have 0 Deg. Front Turret angles, ranging from the vanilla M4 right through the M4A3E2(76) Jumbo M2 and even the Pershings for that matter. Was this the case 'till the end of WWII? How come US tank designers/engineers built bigger angled plates on the Front Upper Hulls during WWII, ranging from 46 Deg. -- 56 Deg., well knowing that these greater angles on plating effectively "thickens" armour against enemy shell penetration, and NOT thicken (via greater angled plates) the front turret for the same effect? Just curious. Or was the front turret plate angle change just to a difficult engineering feat in the factory in such a short time from 1944 untill the end of the war? Any comments from the people that is in the know? Regards, Charl Theron Link to comment Share on other sites More sharing options...
Col Deadmarsh Posted June 22, 2002 Share Posted June 22, 2002 I've wondered this myself ever since I started playing this game. Link to comment Share on other sites More sharing options...
WineCape Posted June 22, 2002 Author Share Posted June 22, 2002 Jason!!!! Link to comment Share on other sites More sharing options...
rexford Posted June 22, 2002 Share Posted June 22, 2002 All of the 75mm armed Shermans had sloped mantlet and turret front armor. CMBO attempts to model the ballistic resistance of the turret front/mantlet as opposed to the thicknesses and angles. For a reason. The later 75mm gun mount had an 89mm cast and curved gun shield spaced behind a 51mm cast and curved rotor shield, so 140mm of curved armor on the turret front mantlet area. Now come the disadvantages, which are considerable: 1. spaced armor is not as resistant as a single plate, so 89+51 does not equal 140. 2. armor is cast so reduce resistance 3. inner 89mm shield is chock full of large openings for gun, vision devices, machine gun, etc, so reduce resistance for edge effects 4. penetrations of 51mm outer shield that fail to go completely through 89mm inner shield may result in something called "keying", where the round sticks in the outer and inner shields and prevents gun elevation changes 5. if projectile penetrates outer shield but is stopped by inner shield and the HE burster detonates, explosion is likely to mess up gun aim and other things. We did a detailed ballistic analysis of the resistance provided by 51mm/89mm shield combo against 75mm hits, which took into account edge effects, cast armor deficiency to rolled armor, spaced armor factor and impact angle. The average resistance of the combo is 89mm vertical, exactly what CMBO uses. Here are some of the breakdowns from our analysis of 51mm/89mm shield combo: 36% hit total effective resistance of 75mm vertical or less 43% strike effective resistance of 85mm or 95mm 13% hit 105mm to 125mm 8% hit 145mm to 165mm NOTE:Above results do not take "keying" into account So 79% of the impacts on Sherman 75mm gun shield area will be resisted by a single vertical plate equivalence of 95mm or less. Since CMBO does not treat the area as a complicated curved arrangement with all of the peculiarities and vulnerabilities, a single vertical 89mm plate is used, which seems reasonable for wargaming. We use the statistical breakdown in our miniatures gaming, so the Sherman shields will occasionally defeat a Panther or Tiger hit, which is likely to stick in the shields and disrupt the gun elevation or detonate and mess up the sight and machine gun. [ June 22, 2002, 07:16 AM: Message edited by: rexford ] Link to comment Share on other sites More sharing options...
rexford Posted June 22, 2002 Share Posted June 22, 2002 Pershing has a curved 114mm mantlet, similar to Panther 100mm mantlet in shape except no tendency to ricochet defeated hits on top of crewmen heads or into their laps. 76mm armed Shermans do have 89mm cast mantlet that is angled at 10° or so. Actual measurements of 76mm gun mantlet show 98mm thickness in two cases as opposed to 89mm design spec. Putting a heavier gun in a tank sometimes means that the turret weight cannot be increased. When IS-1 with its 85mm gun (IS-1 turret designed to balance weight of 85mm gun) is replaced by late model IS-2 with its 122mm gun and very thick and highly sloped front hull, the turret armor cannot be increased. Panther has over 200mm effective vertical resistance against 17 pdr APCBC hits on glacis, but only 100mm cast mantlet cause weight considerations limit turret armor. I would guess that 76mm Sherman mantlets were limited by weight of turret when 76mm gun and new turret replaced 75mm gun and older turret shape. And Pershing turret armor also appears to have been limited by weight issues so resistance could not match upper hull front. Link to comment Share on other sites More sharing options...
WineCape Posted June 22, 2002 Author Share Posted June 22, 2002 Thanks Lorrin! Link to comment Share on other sites More sharing options...
Gen-x87H Posted June 22, 2002 Share Posted June 22, 2002 My guess is production production production. Shermans pretty much were not worth much one on one by the end of the war. But we were producing tham at such a rate Germany didnt have enough guns to stop them. If they took the time to redesign then validate a new design it could have prolonged the war. So they did mini upgrades to try to keep the crews alive longer. But the base of the tank was still the Sherman. That is my opinion Gen Link to comment Share on other sites More sharing options...
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