Mr. Tittles

The Ferdinand had weak top armor and was susceptible to top hits. The driver/codriver were seperated from the rest of the crew by the engune compartment also. A intercomm failure meant no coordination amongst the crew.

RHA? You should state the type of armor being penetrated.

http://www.battlefield.ru/destroyed/germany/panther_17.jpg This panther has had its mantlet knocked off. I recently saw a pic of a panther turm pillbox in poland that was dug up that looked like the same failure. Hits on the mantlet could possibly break the mounting bolts that held the mantlet to the gun cradle.

http://www.quarry.nildram.co.uk/Molins.htm website with 6 pdr info.

76mm APCBC M62 penetrates about 123mm of RHA at 200 yards and 0 degrees, Panther mantlet center is 100mm case, so armor would have to put up 123% of flat rolled armor equivalance to stop 76mm hits beyond 200 yards. And that's on center area hits. The USA catalog lists the 90mm M77 as having 4 in/20 deg penetration against face hardened plate at 1000yds. It lists 4.8 in against homog armor at same range/angle. These values are very close to each other.

http://www.panzerdiesel.com/data/e/27p5_karo.html?SID=e688b03e16b0b83222d331b662a115b1 Heres a panther thats taken some hits. The one hit on the hull barely gouges the armor. The one striking at the junction of the front turret armor and the side armor shows that bthis is a weakness in the interlocked german armor scheme. There might be a ricochet above the turret MG hole. The mantlet appears to be very smooth in this picture. It does not have zimmerit on it. For a cast piece, would you expect such a smooth surface?

The Mycenius data clearly shows that the US 90mm M82 round was inferior to the M77 solid round prior to D Day. The in theatre testing during July showed they were using M77 rounds. The USA catalog lists the 90mm M77 as having 4 in/20 deg penetration against face hardened plate at 1000yds. It lists 4.8 in against homog armor at same range/angle. [ September 20, 2004, 12:53 PM: Message edited by: Mr. Tittles ]

I downloaded it from here. Its the late 44 version and the 75mm solid shot is not even mentioned for the sherman and 1918 guns. http://www.carlisle.army.mil/cgi-bin/usamhi/DL/showdoc.pl?docnum=712 [ September 19, 2004, 06:42 PM: Message edited by: Mr. Tittles ]

The M62 76mm round penetrates 100mm of RHA in U.S. Army Test No.1 Report on Comparative Firing Program Witnessed at Shoeburyness, Essex, 23 May 1944 by U.S. Army Headquarters ETO representatives. at 500m. It does this twice actually with rounds 10 and 11. It does not exhibit BDF going off either. One could logically surmise that at 500 yds range, it had the potential to penetrate the panther mantlet. But in actual test against panther front, it can only penetrate mantlet at 200 yds. The panther mantlet is behaving 'tougher' than its actual thickness. If the M62 could hole 100mm of RHA/30deg at 500m (without any shattter), then why would it not have better performance against a panther mantlet? At 100 yds and 400 yds, it fails to penetrate 120mm RHA at 30 degrees. It again shows that the BDF is not going off. It leaves gouges in the armor as a result of the hits. No where in these tests is there any mention of shattering or hits not leaving gouges. Since it CAN penetarte a panther mantlet at 200 yds, it can be logically stated that the panther mantlet is NOT equal to 120mm RHA/30 deg. In certain spots it may be equal to 120mm+ but not very many. The complete inability of the M72 solid shot to achieve a penetration against the mantlet is very odd. Since the panther mantlet is more than likely just a cast piece of metal, it is should achieve penetration. Its my contention that the mantlet does not behave like sub-RHA and the very agressive curvature does play into the penetration equation. It can not be equated to equations like other armor is. The 90mm solid shot M77 round does penetrate the panther mantlet, bow and turret. Interestingly, the 90mm has a harder time against the mantlet than the vertical turret front! I suspect that the typical T/D rules are being altered by the curvature of the armor. The mantlet is acting like a tough nut to crack. The penetrating round is experiencing an increase in armor resistance as it moves through the armor. It must push material out of its way and is also experiencing side forces as it moves through. Its being squeezed and opposed. Its acting like its 'depth-hardened'. Another mantlet consideration is that the extreme edge angles would not allow penetration. Even the 17pdr APDS would ricochet (mycenius). The need for a round to get at least half its diameter into the mantlet needs to be considered. The point of the AP round must be able to engage the armor to penetrate. Many hits along the upper inches would just direct the round off into space (or towards the driver/radio-operator compartment for downward ricochets). [ September 19, 2004, 06:24 PM: Message edited by: Mr. Tittles ]

The US Army standard catalog of Ordnance lists the 76mm M79 against FH armor as 3.2in (81mm) at 500 yds and 2.8in (71mm) at 1000yds. This is 20 degree FH armor. I doubt that it would penetrate 124mm at 250m. You are probably looking at Homog penetration values. 76mm M79 Homog armor 20 deg 116mm at 500yds 101mm at 1000yds.

US 76mm 20deg M62 500yds Homo 4.3" FH 4.5" M79 500yds Homo 4.6" FH 3.2" This data shows the fall off the M79 round to FH armor. [ September 18, 2004, 10:10 AM: Message edited by: Mr. Tittles ]

If 76mm APCBC hit the Tiger driver plate at 12° side angle, the resultant resistance would equal 109mm at 0°. With shatter gap, rounds fail when they have 1.05 to 1.25 times the armor resistance, which would result in M10 failures from point blank to 550 meters range, and then penetrate from 550m to 750m. On M10 hits against the Tiger side armor at 30° side angle, the resistance would equal 103mm at 0°, and M10 hits would be expected to fail from point blank to 800m, and then penetrate from 800m to 1000m. http://spwaw.com/lholttg/penetration.htm ?

20 deg M70 57mm AP HOMO 500 3.9in 1000 2.9in Face Hardened 500 3.2in 1000 2.4in 57mm M86 APCBC HOMO 500 3.3 ins. 1000 2.9 ins. FH 500 3.4 ins. 1000 3.1 ins. This is penetration data for US 57mm ATG using US ammo. It, like the US 76mm ammo, shows the same properties as far as the solid shot doing better against homog armor, but not as well against face hardened armor. If you read through.. http://www.thetroubleshooters.com/history358.html The US unit trades AP rounds (I would guess APCBC) for british HE. The British had a AP ammo shortage and the US unit no HE. The US unit goes on to use its HE to good effect, but I wonder about the brits (maybe they only had APDS and it was innacurate?). In any case..there is evidence that US units also had APDS.. http://www.bluespader.com/Pg13.html [ September 17, 2004, 05:30 PM: Message edited by: Mr. Tittles ]

I think the ability of the 76mm M62 to penetrate and the inability of the 76mm M79 NOT to penetrate is more pertinent than your approximate locations of 6 pdr hits. It certainly seems that the mantlet was not RHA-like but rather face-hardened -like. You have a very strong propensity to throw this shatter-gap into any situation where you can. In this case, its inmaterial. Whether the US 76mm had shatter gap does not address the fact that the US 76mm M86 COULD penetrate the Panther mantlet at 200 yards or so AND the 76mm M79 could not. Do you think any of the Mycenius data supports any shatter-gap theory? [ September 17, 2004, 04:51 PM: Message edited by: Mr. Tittles ]

Curved surfaces distribute stress better than sharp-cornered welded boxes, so curved mantlets acted a bit thicker than their weak granular structure would lead us to expect. That is, they were kinda the same as if they were RHA. http://www.yarchive.net/mil/ww2_tank_armor.html

Perhaps theres a clue in the U.S. Army Test No.2 Firing Tests conducted 12-30 July 1944 by 1st U.S. Army in Normandy. The M79 76mm round clearly is inferior to the M62 76mm round against the Panther front. The M79 round is just a heat treated slug (AP round) and does very well against homo armor. In fact, better than the M62 round will. But it is inferior to the M62 when attacking face hardened armor! So does the cast mantlet act like face hardened armor? Is it possible to face harden the mantlet after it has been machined/drilled/etc?

U.S. Army Test No.1 Report on Comparative Firing Program Witnessed at Shoeburyness, Essex, 23 May 1944 by U.S. Army Headquarters ETO representatives. http://www.geocities.com/mycenius/ The 76mm M62 in this test seems to show that it could hole (PTP-projectile passes through) 100mm 0f RHA at 500m. It actually outperforms the 'new' 90mm M82 APHE rounds (which seem to predetonate). Note that the BDF does NOT go off in the M62 round. That is, it not only does not experience shattering, it does seem to exhibit fuse failure. In this test...U.S. Army Test No.2 Firing Tests conducted 12-30 July 1944 by 1st U.S. Army in Normandy. 7) 3-inch Gun, M5, mounted on Motor Carriage, M10 a) APC M62, w/BDF M66A1 will not penetrate front glacis slope plate at 200 yards. Will penetrate gun mantlet at 200 yards and penetrate sides and rear of the 'Panther' Tank up to 1500 yards. AP M79 will not penetrate the front slope plate or the mantlet at 200 yards. It holds no advantage over APC M62 ammunition w/BDF M66A1. So there appears to be something beyond the rexford crunched numbers going on. The 76mm M62 round does not shatter at 500m against RHA. Is cast armor so much harder that it causes shatter? If the M62 round DOES penetrate the panther turret at 200m, why not 500m? Why is the Panther turret inferior to the mantlet when fired on by 90mm M77 AP ammo? The evidence does not support rexford's calcs. the mantlet does not appear to be as weak as he would imply. [ September 17, 2004, 10:09 AM: Message edited by: Mr. Tittles ]

http://www.geocities.com/mycenius/ http://www.100thww2.org/support/77657mm.html If the Panther mantlet was so vulnerable to 57mm fire, why would these reports not note it? Heres some interesting reading about 57mm use against a Panther. Note the lucky hit is not a mantlet bounce but a turret ring hit. On this day an excited GI came running up to our position and told us to get the gun back down the road a hundred yards or so as a Panther was sitting out in the open. We were able to balance the gun so that it could be hand wheeled short distances. This we did. When we swung it off of the road we rolled it into a shallow depression beside the road. That lowered our profile to about chest height. Within seconds we had a round chambered and fired. That one caroomed off the turret. The next one had to be one of the luckiest shots of the war. It hit on a narrow ring between the turret and hull, which the turret rotated on. The shot locked the turret so that the only way the tank could traverse its gun was to rotate the entire tank. This they did. But we were not a very big target, so they never saw us. Ask any tanker and he will tell you that a tank that is "buttoned up" is stone deaf and about 90% blind. We hurriedly poured about 5 more rounds into the Panther. One caused him to throw a track so he was unable to escape. At that point the Panther crew started to bail out. We had gotten our kill! http://www.thetroubleshooters.com/history358.html [ September 17, 2004, 08:48 AM: Message edited by: Mr. Tittles ]

Isnt this the same drawing as seen earlier in this thread?

The amount of offset a sight has from the barrel of a gun effects the ability to 'pin-point' an area. The offset being nearly equal to the tube width makes for very lucky shooting. A weapon like the soviet ATR has sights very close to the gun tube line. They would and could target very small targets on the afvs. They, of course, alos fired from very short ranges also.

I would guess the mantlet was made as follows: 1. Pour molten metal into cast with gun tube protector at the top (the part the gun protrudes through). 2. Remove from mold and machine the gun tube hole to spec. 3. Machine MG and sight ports and check for minimum acceptable 100mm depth after drilling holes. This assures thickness at two points (thinnest points perhaps). 4. Attach lifting eyes. 5. Machine back of mantlet to accept gun cradle. Drill trunnion bolt holes.

This is news. Most sources state a higher velocity for the PAK40 weapons. The higher velocity for the shorter L46 weapon did always seem odd. But what about the penetration differences then? I believe the sights are not the same? There could be confusion about the pak39 (hetzer gun) and pak40 perhaps?

It could also be from the APHE detonating before penetrating. I think this problem effected US 75mm/76mm (APHE) and 90mm(M82). Shatter gap and predetonation would basically fail the projectile in the same manner. The only conclusive shatter gap would be a non-HE AP round (solid shot).

Could the actual shape of the armor reinforce its strength? This is the egg shell effect. Eggs are very strong against attack from outside but easily broken from inside. AS a AP penetrator tries to punch a plug through armor that is rounded aggresively, like the panther mantlet, it is being resisted by not only the armor directly in its path, but also by the armor in the immediate sides. Its sort of the arch effect on a bridge. From the numbers, it would appear that the mantlet would not resist attacks like it did. Even the US 90mm AP (M77) round had a tougher time on the mantlet than the strait up turret front 110mm. Mycenius.. 8) 90mm Gun, M1A1, AA AP M77 will penetrate front glacis slope plate up to 600 yards, the gun mantlet up to 1,000 yards and the turret up to 1,500 yards. [ September 15, 2004, 07:39 AM: Message edited by: Mr. Tittles ]

Great stuff. Thanks. </font>