Jeff Duquette
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Posts posted by Jeff Duquette
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Hmmm...this is private correspondence between you and Zaloga, or can you provide a link or reference to the above? This is a pretty bold implication to randomly throw about as you have done without some sort of reference. One would hope that the S4 reports for the battalion in question & divisional G4 reports for the day of, as well as the next day or two would be employed to verify. Further crossing checking of what were complete losses and those that may have been knocked out but were recoverable and repairable.Originally posted by michael kenny:The above is a typical reply (not intending to start an argument here)in that people 'know' the Germans had a strict verification system. Everyone 'knows' it but no one knows what it was or how it worked!
Barkman on 27/7/44 has a high profile as well but a recent reply to me from Steve Zaloga states that the 3rd AD losses that whole day were just 3 Shermans.
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I don't know what the previous poster may be referring to. I may be wrong on this, but I think all of the marks of 45mm APBC used a small bursting charge. On the other hand, 45mm APC -- as far as I know -- never included a bursting charge. Some of this might be attributable to developing training rounds that aren’t leaving explosive charges on training ranges. I mean it’s all sort of interesting, but a bit vague.Originally posted by MikeyD:I recall an earlier CMBB discussion about 45mm gun ammo. The poster had stated that as the war progressed Russia transitioned from 45mm APHE to straight AP. He concluded from that that they had dropped the HE fill due to negligable effect. My alternate take on it was that the HE fill was dropped because its only useful if you achieved penetration! First they had to concern themselves with successfully piercing an 80mm PzIV hull front, after that they can consider behind-armor effects. By mid-war the obsolescent 45mm gun simply needed the kinetic punch of solid shot to achieve its minimum aims.
As to dropping the bursting charge on the part of British for their AP -- I don't disagree that the ability to perforate more armor than AP-shell was as likely a motive as any -- and I said as much several times fairly early on in this thread. The other motive was probably associated with the Germans use of spaced armor add-ons and British tests on spaced plates -- and picric acid can be fairly touchy to shock and friction of impact under certain conditions. AP-shells had a tendency to explode between plates resulting in a much reduced penetration capability. Another motive may have been that is much easier to produce solid shot than it is to produce AP-shell. The point is of course, that there are a number of possible motives that do not necessarily equate to the argument that the British used AP-solid shot because it was as effective in behind armor effects as AP-shell. And in spite of all the twists and turns in thread, the point originally being argued regards behind armor effects and what one might expect in behind armor effects for AP-shell and AP-soild. Behind armor effects presume perforation has occured. Arguing about penetration capability by a specific projectile is alway interesting, but as I see it, sort of tangent to the original intent of this disscussion.
Regarding modern armor and laminates and spall liners and such -- we are now talking about a wide range of potential threats which will have an equally wide variety of potential behind armor effects. For example a tungsten carbide (WC) core AP bullet will pretty much shatter following plate perforation. Makes for excellent behind armor fragmentation. In addition thin HHA plates(not to be confused with FHA) are often used when the the design threat is small arms or medium caliber projectiles. High Hardness Armor or very high hardness armor is very efficient at breaking up projectiles or enhancing richochet potential. But they are also more brittle than RHA. In defeating a small caliber projectile the low ductility can result in some back spall. This is easily delt with via a light weight spall liner.
The WC core, in and of itself generates a large amount of secondary fragmentation into a confined crew compartment. The same sort of thing is associated with APCR or HVAP or APDS using WC cores. The cores themselves consist of very heavy and very brittle material that invariably shatters following plate perforation. Behind armor effects associated with the WC core shattering are therefore good or very good.
Same again is associated with WHA rods or DU rods or HEAT. The very high impact velocity associated with long rod penetrators -- 1.4Km/s(+) -- will generate large amounts of secondary fragmentation from both plate spall as well as the secondary fragmentation from the penetrator break upon. HEAT perforation will also potentially throw a large amount of very high velocity spray from the jet into the crew compartment -- dependent upon the magnitude of "over penetration" associated with the jet and armor it is defeating. The point here is that hydrodynamic perforation associated with WHA or DU LRPs or shaped charge jets or EFPs or whatever and their associated behind armor effects are not nessecarilly reflective of the sort of behind armor effects associated with much slower, full caliber ductile steel projectiles vs. monolithic ductile steel targets.
I mean don't get me wrong -- steel plates and steel projectiles will spall and shatter and generate secondary fragmentation. But this can be minimal or it can be alot (ala Italian tank armor).
Best Regards
JD
[ February 02, 2007, 10:09 AM: Message edited by: Jeff Duquette ]
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Attached is a sectional of 5cm pzgr.39. The explosive filler weight is listed as 0.027Kg – which I assume includes the booster weight (or the gaine for the British speaking members of the audience). The British War Office Intelligence series on enemy ammunition lists the filler as being 14dr of an 87/13 blend of PETN & wax. or ~0.025Kg of PETN\wax.
The uncapped 5cm pzgr, which predates the pzgr39 -- used a smaller bursting charge – 0.017Kg – also PETN\Wax.
Best Regards
JD
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PreciselyOriginally posted by John Kettler:Jeff Duquette,
The Hogg piece is informative and intriguing, but in it he flatly contradicts what he said about the same issue in THE GUNS 1939-45.
The photo is the photo. It is reflective of minimal back surface throw.The SAPHE photo is most helpful, but I think that what we're seeing is probably representative of more yielding armor, such as RHA, rather than, say, face-hardened plate. Combat damage shots I've seen would appear to confirm that, too.FHA was of course brittle on the face -- make sure you distinguish in the photos the difference between front and back surface. The contrasts in failure mechanism between the two surfaces will typically be quite dramatic.
Only The first few mm's of FHA will be cemented(or the first few cm's depending upon the overal plate thickness). But of course the greater proportion of plate consists of a ductile backing. The back section of the plate is ductile for the specific reason of minimizing back surface fragmentation. The super hard face breaks the nose of the projectile, while the ductile backing reduces backsurface effects.
Like RHA, FHA was of course subjected to compliance standards and compliance testing. Each heat would have samples extracted for ballistic testing. British, German and American compliance standards also included both limit velocity specifications as well as backsurface spalling specifications to which the samples were expected to adhere. The latter requirement of course being to minimize back surface spall. Obviously as the war progressed German plate quality began to decline, but from what I have seen on the subject panzer armor plate in the 1939 - 42 period was generally good to very good material.
Most armor doesnt simply "explode" when a projectile strikes it, or a projectile perforates it. That sort of defeats the purpose of the armor. The Italians seem to have had problems with this as indicated by one of my previous references, conversely the same quote implies that British armor did not have the same issue. German armor -- RHA and FHA -- seems to have preformed about as well as British in this period. The various accounts of 2-pdr AP penetrating German panzers and the panzer continuing to move and fight -- at least to me -- suggests back surface effects of these penetrations were not particularly dramatic.
very well. i actually have a 5cm pzgr projectile in my collection -- as well as sectional drawings, firing tables, testing data, blah blah blah. i'll post something latter on this projectile.How are you fixed for drawings and tech data on the German 5 cm short APHE projectile?
[/QB]
[ February 02, 2007, 05:59 AM: Message edited by: Jeff Duquette ]
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This is sort of interesting. Here Ian Hogg is suggesting that the German 37mm pzgr projectile was slightly superior to the 2-pdr AP-solid shell because the German projectile contained an explosive filler.
Ian Hogg, “Armour In Conflict, Page 103.
“On the other side of the line the German tanks were equipped with either a 37mm high-velocity or a 75mm low-velocity gun. The Germans never used plain solid shot: with the exception of composite shot (noted below) all their projectiles carried a charge of high explosive and a base fuze, so that their 37mm gun had a slight edge over the otherwise comparable 2-pounder.”
The image below is a 35mm Oerlikon SAP-HE projectile bursting after perforation of what appears to be a 20mm or 30mm plate. Of interest is relative amount of back surface fragmentation generated – i.e. very little. Conversely the bursting charge is generating a fairly generous amount of fragmentation. Now this isn’t completely gratuitous. Moreover the SAP-HE shell has a larger bursting charge than 37mm pzgr. What this does show is that it is not a given that back surface fragmentation is necessarily particularly devastating and additional fragmentation from a bursting charge certainly can’t hurt, and may represent the lions share of behind armor effects from projectile perforation.
Again back surface fragmentation may consist of only one fragment – the projectile itself – at intermediate velocities against thin plates. This is basically a petal type failure of the plate in which no spall is generated by the passage of the projectile through the plate – ala a AP projectile passing through the thin skin of a truck or a half-track.
Backsurface spall may represent the formation of only one plug about equal in diameter to the caliber of the AP Projectile. Plug failure. Plugging represents a shear failure along a fairly well defined plane through the plate.
Or you can also get a combination failure in which a few (ala the Oerlikon image), too many fragments can be thrown off of the back surface during projectile perforation.
Either way you slice it the math is relatively simple. You can twist and turn but in the end there is spall and there is bursting charge fragmentation. 2pdr AP-solid don't get any bursting charge frag, 37mm pzgr does. So my math -- as originally presented by me -- is pretty much the math.
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It’s been suggested that 2-pdr AP-shell was considered no more effective than 2-pdr AP-shot in generating behind armor effects. This is based on a quote from Hogg’s book on US and British Artillery. The Hogg quote is at odds British field trials briefly discussed by Jentz in his book on Tank Combat in North Africa. Be that as it may.
Hogg’s take on 2-pdr AP-shell has been used as an example to demonstrate that other small caliber projectiles must be equally ineffective in generating behind armor effects. There isn’t anything wrong with using this logic, however additional information – to include the Jentz quote – has been presented to suggest that AP-shell might be more effective than is being argued. In addition, and more specifically 37mm pzgr might not be directly comparable to Hogg’s take on the 2-pdr AP-Shell. To recap:
1) Small caliber bursting charges can in fact generate effective fragmentation. Even 20mm projectiles with small bursting charges can generate in excess of 100 effective fragments. If a projectile by bursting can throw additional fragmentation into a crew compartment in addition to whatever fragmentation is developed during plate perforation why would it not be more effective than solid shot?
2) All other major producers of tank fired AP projectiles during WWII employed various forms of AP-Shell. These other producers appeared to have thought that a bursting charge would enhance behind armor effects. This to include the USA, Russia, Germany, and Italy. Lesser known producers of AP-HE (large and small calibers) for tank and anti-tank fired projectiles included the Czechs and the Poles (there are probably more on this list, but I am sticking to information I have seen). These AP-HE shells ranged in caliber from 20mm to 128mm.
3) The British – aside from the already mentioned early versions of 2-pdr AP-Shell (and 3-pdr APHE) – did not use bursting charges in any of their tank fired AP projectiles. To elaborate a bit, in my mind there is no direct correlation between the fact that the British didn’t use a bursting charge in 2-pdr and all small caliber AP-Shells bursting charges being ineffective. This argument misses the fact that no British tank fired AP during WWII used bursting charges. So by this same logic we might conclude bursting charges for both small and large caliber projectiles were ineffective – all because the British didn’t use bursting charges in any of their tank fired AP projectiles. One would therefore have to ask where the cross over point is. 2-pdr and 37mm to 47mm(?) calibers; 6-pdr and 50mm to 57mmcalibers(?); 17-pdr and all 76mm to 85mm caliber(?) , 20-pdr/ 90mm to 128mm(?). Or does this argument extend further up the food chain – were the bursting charges in 14-inch APC, 15-inch APC and 16-inch APC also ineffective at enhancing behind armor effects?
4) The 2-pdr AP-shell referred to by Hogg is of course not German 37mm pzgr. The contrasts between 2-pdr AP-HE and 37mm AP-HE include what appears to be a larger bursting charge within the 37mm pzgr. In addition, the explosive filler utilized in the two projectile differs. 37mm pzgr uses a much more modern and more powerful explosive than the 2-pdr AP-HE shell. PETN in the 37mm pzgr vs. Picric Acid in the 2-pdr MkI APHE shell. The level of fragmentation generated by a bursting charge is correlated to the power of the explosive used in the bursting charge (see attached).
The attached figure represents testing data from the US Army’s Material Testing Laboratory – circa 1950’s thru 1960’s. Sorry -- no fragmentation data for picric acid as the US had deemed this particular explosive unsuitable for use in High Explosive bursting charges even before their entry into WWII. Extrapolation of this data (fragmentation as a function of explosive power) suggests that based upon bursting charge material (i.e. Lyddite at about 100% and PETN at about 166%) we could expect about a 50 to 60% increase in fragmentation for the PETN charge over Picric Acid. But of course it is better than this (or worse depending upon your perspective). The 37mm pzgr bursting charge appears to be bigger than 2-pdr AP-HE, and of course fragmentation is also proportional to the size or weight of the bursting charge.
The equation therefore looks something more akin to:
2-pdr AP-solid shot generates “X” number of fragments during plate perforation.
It’s behind armor fragmentation therefore equals X
2-pdr AP-HE also generates “X” number of fragments during perforation and in addition it generates “Y” number of fragments by the bursting charge. It’s behind armor fragmentation is therefore:
= X + Y
37mm pzgr AP-HE also generates “X” number of fragments during perforation, but it generates 1.5 to 1.6 times Y fragments from the bursting charge because it uses PETN instead of Picric Acid (note there is not accounting here for the larger 37mm pzgr bursting charge).
37mm pzgr AP-HE behind armor fragmentation = X + (1.5Y)
For giggles lets put some arbitrary numbers to this cause' some folks don’t like “X’s” and “Y’s”.
Lets say plate perforation generated fragments “X” = 100 effective fragments.
Lets say bursting charge generated fragments for 2pdr APHE “Y” =100 effective fragments
2pdr Solid Shot therefore introduces 100 effective fragments into the crew compartment
2pdr APHE introduces 100 + 100 = 200 effective fragments into the crew compartment
37mm pzgr APHE introduces 100 + (1.5 x 100) = 250 effective fragments into the crew compartment
Ok – quiz time:
If you wish to maximize kill probability against a tank from projectile penetration, does it make more sense to:
a) Introduce 100 fragments into the crew compartment; or
Introduce 200 effective fragments into the crew compartment; or c) Introduce 250 effective fragments into the crew compartment.
[ January 29, 2007, 12:42 PM: Message edited by: Jeff Duquette ]
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never mind...my post wasn't constructive...aside from pointing out folks should wade through from the begining before honoring us with their insights.[ January 29, 2007, 05:29 AM: Message edited by: Jeff Duquette ]
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here we go. this is the mkIV spaced armor I was thinking of. these are from photos i took at aberdeen a couple of years back. most of the mile of tanks near the entry gate have been restored to this sort of condition. pretty nice. even gotz' an Afrika Korps palm on the thing.
and Crisp’s Stuart
-- that's my finger on the second photo doing a highly calibrated measurement of the frontal armor thickness.
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Well thanks anyway. I'm prolly going to far afield with this stuff anyway.
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Sounds like your pretty up to speed on this ****. You do flight sim games as well as Combat Mission?Originally posted by Stalin's Organist:Mig cannon fire was certainly very destructive - the 2 x 23mm cannon were appreciably more powerful than 20mm cannon and the 37 could blow any aircraft out of the sky with a single hit - the armament combination was designed to shoot down bombers, which it did very well and forced an end to daylight bombing of Nth Korea.
However the cannon were very slow firing compared to 6 x .50 cal's, so arguably not so useful vs small, fast-moving fighters.
I'm not very hep on cannon load-outs for aircraft. Did the Korean War Migs use a mixture of ammo types for their cannons? OZT and BZ. Or did they pretty much use only BZ if dog fighting was anticipated?
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Thnx Stalin. Sorry -- don't wanna continue off into la-la land relative to the thread topic, but the page also goes on to say:
"The combat tests were sufficiently encouraging that the T-160 cannon was placed into production by a division of the Ford Motor Company as the M-39, and the cannon ended up arming the F-86H and some of the Century Series of supersonic fighters."
I thought I read something once about Mig cannon fire being considered to be pretty destructive relative to 50-caliber fire. But I may be thinking of something else
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Hi John:Originally posted by John Kettler:civdiv,
Fair point!
Jeff Duquette,
I just had a Eureka! moment awhile ago when I remembered something potentially very useful from my Hughes days. Back in the late Seventies or early 1980s, the Russian surface fleet became a major threat, and the Navy found itself in the embarrassing position of not having proper munitions to kill ships and was forced to improvise with things like the Skipper, a laser-guided 250 lb. bomb with wings and a Shrike rocket motor in order to not get eaten alive by ship based AAA and SAMs. On my end, we did a crash analysis of the still in dev Maverick MAW (Maverick Alternative Warhead) as a shipkiller. This was how I got exposed to the Project Thor equations (q.v.) developed by Bernier
http://www.bahdayton.com/surviac/archive/surviac_bulletin/bulletin_9802/page1.html
Basically, these equations addressed the damage potential to structures (and men?) from fragments of various materials and sizes, traveling at different velocities. Thus, given fragment X, at velocity Y, will it penetrate structure Z with the following material properties? I didn't get into it very deeply, being chiefly involved in figuring out how deep into the ship various weapon installations went for purposes of determining target size, aimpoints and the like, but I did help out for a few hours using a simple program our weapon analyst made and loaded into my calculator. What we were interested in was fragment capability to pierce bulkheads, overheads, and hull, not to mention piercing missiles and torpedoes in their launch tubes, penetrating gun houses and the like.
The above seems to be to be very much along your lines of interest. Further, I remembered two other things. Blast studies are conducted by converting all explosive yields into TNT spherical charge equivalents, and you already know that blast goes up as the cube of the TNT charge weight equivalent. The other item is that the AGM-45 SHRIKE antiradiation missile had as its primary destruction element, a warhead whose frag portion was composed of thousands of 1/4 inch tool steel cubes. This design was carefully chosen because the frag size allowed for lots of fragments, each capable of ripping into a radar control cab and wrecking whatever it struck inside, while shredding above it the radar antenna, feedhorn, waveguides, etc. Given this, it seemed to me that this might be a good first order approximation for the, er, APHE experience.
In fact, it may, based on your drawings and photos of the 3.7 cm shell, be understating frag size, but even so, should give you something with which to work. Wounding potential methodology is well established (if it'll pierce 1" pine, it'll incap a man), so all you'd really need for a quick study would be cartridge casing wall thickness and material, for that issue is what drives overall APHE lethality, ammo vulnerability. Got any 2 pdr. AP round sectional drawings?
Regards,
John Kettler
I do have a large amount of material on fragment penetration of various materials and some material on wound ballistics – although the latter is not really my cup of tea beyond having some cursory background knowledge.
When I say "Effective Fragment", it is relative to the fragments ability to generate a penetrating wound into a human. The 20mm M97 generates more than 111-fragments on average. It’s just that only 111 are deemed to have sufficient energy to wound or kill someone.
The pine board and straw board methods of determining effective fragmentation were one way of doing things. Obviously wound ballistic tests and associated algorithms have developed a long way from WWI and WWII. But the rule thumb used to be 58-ft-lbs of energy at impact. The British rounded it 60-ft-lbs (or maybe the British value reflects what it would take to penetrate a Scot). You still see studies that bandy this number around. The original source dates back to German shrapnel ball testing that predates WWI (and I don't mean shell fragments -- I mean tests with lead shrapnel balls). In that sense this number is valid, but you need to be careful in its application as it is specific to a certain fragment mass and areal footprint. I worked it out sometime ago and figured the impact velocity was about 360-fps for an approximately ½” diameter lead shrapnel ball (about 190-grains).
But a major league baseball pitcher (I guess this might be a bowler in Cricket) can hit you with a moderately fast pitched ball and deliver a blow with 58-ft-lbs of energy. The baseball hit won’t usually kill you nor do much beyond give you a bad bruise. So you need to think of the energy requirement for an effective fragment in terms of energy density. Sort of like a gal in high heels and the amount of pressure she is exerting to the tip of that high heel relative to if that same gal were wearing bozoo the clown shoes.
Regards
JD
[ January 28, 2007, 01:05 PM: Message edited by: Jeff Duquette ]
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This is a good point and I totally agree with you bringing it up. Although to be fair John S. does make an attempt to futz around with residual velocities in the next paragraph. I didnt want to touch it cause I wasnt sure if Naval fuzes use longer delays or not.Originally posted by civdiv:In regards to the delay and estimation of the shell travelling 6 feet within the tank I think you fail to take into account a couple of things. First, dependant on range of course, the round isn't travelling at 2,000 FPS when it gets to the target. Second, and IMHO more important, it isn't going 2,000 FPS after striking and penetrating the armor.
There maybe something there or there may not. I think he's trying to put some numbers to this thing. Often putting numbers to these sorts of things will put them to rest.
[ January 28, 2007, 11:54 AM: Message edited by: Jeff Duquette ]
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We have Hogg and we results from some test at Beda Fomm. The two conclusions are at odds with each other. We know the Jentz thingie is based upon some sort of ad-hoc tests conducted by 2nd R.T.R. at Beda Fomm. I assume we haven’t a clue on the source of Hogg’s premise?
To Recap:
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"Shell, AP, Mk. 1. This shell was part of the original specification for the gun, and was a piercing projectile with a tiny filling of Lyddite and the Base Fuze No. 281, which carried a tracer. Experience revealed that on impact, the fuze tended to part company with the shell and thus fail to initiate the filling. Moreover, even when it worked correctly it appeared to do no more damage than a plain steel shot, which was easier to manufacture. As a result, the AP shell was withdrawn."
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4.1.1.1 BRITISH GUNS AGAINST AXIS TANKS
Directly after the battle of Beda Fomm, the 2nd R.T.R. conducted tests to determine the vulnerability of the Italian M. 13-40 tanks. They reported on 14 February 1941: During the morning tests were carried of the effect of the two types of 2-pounder ammunition on Italian M13 tanks. These tests proved that the yellow painted explosive armour piercing projectile penetrates the armour at 900 yards and bursts inside with very destructive effect. Sand bags placed on the crew's seats were well riddled with splinters. The black painted solid A.P. projectile also penetrates at 900 yards and causes large cracks in the armor.
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On the differences between 37mm pzgr & 2pdr AP-HE:
The Germans apparently used Pentaerythrite Tetranitrate in the bursting charge for 37mm pzgr. PETN didn’t really evolve until after WWI. The brisance of PETN is pretty high. Higher even than RDX. It’s about 166% that of TNT.
Lyddite…hmmm Picric Acid. A throw back to the Great War I think – pre-Great War actually. Picric acid has a much lower brisance than PETN. It’s brisance is about that of TNT – or about 100% -- which is good, but certainly well below PETN.
Picric Acid can apparently combine with moisture or other metals to form rather unstable picrates. Picrates are apparently very sensitive to shock and friction. Moreover they tend to go boom under shock -- like a high velocity impact maybe. No idea if this contributed to the British problems with bursting charges or not. But it is interesting. In fact the British War Office manual on Ammunition “Text Book of Ammunition, Pamphlet No.1 Explosives” (dated 1944), page-24 indicates the following about Lyddite (or picric acid):
“Picric Acid is not always sufficiently insensitive to withstand impact on armour, and it is therefore unsuitable for armour-piercing projectiles.”
Well **** howdy – let’s put it in our armour piercing projectiles anyway
WTF? See the attached scan below.
Do we have a weight for the picric acid bursting charge in 2pdr MkI AP-HE. Anyone – Anyone – Buller? I have the scale sectional shown below -- from a German UXB manual. The bursting charge cavity for the 2pdr MkI looks somewhat smaller than that of 37mm pzgr. But this could be my imagination. In lieu of a bursting charge weight, a specific gravity or density for picric acid might be helpful. The weight of the bursting charge could than be back calculated.
[ January 28, 2007, 12:42 PM: Message edited by: Jeff Duquette ]
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The following is an interesting snippet from one of those overview papers on Armour Penetration. Dunno the exact title of the document as I only have scans of bits and pieces, but it is apparently kept in the Bovington Tank museum archives – something to the effect of Armour Penetration or some such thing.
My interpretation – which would of course be considered jaundiced by some given my stance on this topic – is that Italian armor was resulting in a large amount of fragmentation from projectile perforation. In this instance a bursting charge would probably add little in the way of behind armor effects – unless of course you are of the opinion that a tank crew needs to be killed twice or three times.
On the other hand it seems to imply that good quality British armor was not spraying crews with armor plate spall from projectile perforations. Perhaps I would want a bursting charge that functions properly in this instance.
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I think I indicated the weight of the 37mm pzgr bursting charge in one of my above posts.I have dug quite deeply in my way less than exhaustive references and other than Hogg, have naught to show for the 3.7 cm APHE's exact explosive load, but I do have a data point for comparison. From Hogg's AMMUNITION, p. 149 in the drawing of the 3" shell with Projectile, fixed, A.P.C. M62 with fuze BD M66A1 and Tracer. Explosive filler is listed as 0.14 lbs. Explosive "D."Regards,
John Kettler [/QB]
[ January 28, 2007, 07:13 AM: Message edited by: Jeff Duquette ]
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I’m not sure I understand your first sentence. They are personal observations so they hold less weight? Is that your point?The passages from Jarrett John K seems to have agreed are his source are, let us be clear, not OR studies (MELF stands for Middle East Land Forces, btw, John), they are personal observations. When I read them I took them to be an indication of the need to improve ammunition stowage to prevent "brew-ups", and on re-reading they still seems to say the same. British tank desgners took up a policy to deal with this problem, adding armoured stowage bins and declining to stow ammunition above the turret-ring.[/QB]
Ok, so they added stowage bins and added encased ready racks or whatever. Good idea. But how does this equate to bursting charges being ineffective? If they added storage bins maybe it was because bursting charges were effective?
The British did use bursting charges in the early version of 2-pdr AP. It's commented upon in one of those bits I quoted from Jentz. I also have a scale sectional of 2pdr Mk-I AP-HE projectile laying around here in my junk somewhere. In addition, I think you commented earlier upon 3-pdr AP-HE -- I assumed you were refering to the 3pdr tank gun. It seemed to have been used by the Land Service early on. But of course its use was discontinued early on as we dont see bursting charge in later marks of 2-pdr, or in 6-pdr or 17-pdr. But this doesn’t lead to the conclusion that behind armor effects of AP-HE were ineffective. And I find no reason to disbelieve master JentzIf the passages were really intended to convey the message that APHE is a crew-killing wonder-weapon, then I am at a loss to explain why nobody in the OR or tank design communities ever (as far as I know) called for APHE to be adopted for land service, or why the supposedly fearsome destructive qualities of APHE mysteriously escape mention in all the personal recollections of British tank crew members (Joly, Crisp, Tout, Foley, Wilson, Farrell, Hills, Dyson -- there are quite a few of them).
All the best,
John. [/QB]
. Moreover discontinued use by the British, as I have already stated, appears to be associated with the ability of AP-solid to perforate more armor than AP-HE. In addition, AP-HE has a tendency to predetonate if spaced armor is employed -- and the Germans were using spaced armour on later versions of the Mk-III (and I think Mk-IV). Regarding Crisp and the like, lack of evidence is now evidence? Nobody mentioned it therefore it's not effective? Maybe it wasn't mentioned because the guys that were most effected by bursting charges weren’t around after the fact to comment upon the effectiveness or lack thereof.
All your doing is reiterating that the British had a different philosophy on this subject than the US, Germans, Russians and Italians. Why would I be inclined to think the British approach in using solid shot is more valid than any of these other group of folks and their use of AP-shell? The fact that British experience with AP-shell was poor doesn’t help to bring me to a conclusion that the same is true for US, Russian, German or Italian AP-shell.
[ January 28, 2007, 07:14 AM: Message edited by: Jeff Duquette ]
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Interesting. Well I stand corrected. Thnx for the link. I didnt look too closely, but were any of these F-86 involved in air-to-air combat -- any confirmed air to air kills?Originally posted by Stalin's Organist:4 F-86A's experimentally armed with 20mm cannon were trialed in January 1953 and 282 combat missions flown - see Joe Baughers F-86 page
[ January 28, 2007, 07:16 AM: Message edited by: Jeff Duquette ]
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Not to diverge off into la-la land again, but what "classic" 20mm round are you refering to, and what US Aircraft was firing 20mm in air-to-air over Korea? F-86 used 50-cal.Originally posted by John Kettler:Apparently, the classic U.S. 20mm round used from the Korean War through the Vietnam War for air-to-air was pretty anemic in the blast department, so much so that on detonation, there was practically no side spray of fragments at all.
Our weaponeer at Hughes showed me the data himself.
Basically, they barely emerged laterally but were overwhelmed by the forward velocity component.
Regards,
John Kettler [/QB]
As to the classic round being "anemic" -- I suppose it is a relative thing. If your weapons expert was expecting the same sort of fragmentation associated with a 105mm HE round exploding, than yes, 20mm is very anemic
But 37mm pzgr isnt a 105mm HE projectile. It’s bursting charge weight is greater than, but closer to that of 20mm M97 HEI. Now I have the data for 20mm M97 HEI, see attached. I'd be interested in seeing this other data you are referring to. Might be interesting to compare whatever projectile your dude was referring to. The M97 projectile data shows an average of 111 effective fragments ranging in velocity from about 1500-fps to about 891-fps.
We’re not gonna get anywhere broadsiding with anecdotes. So what is it in your last post that advances the discussion toward some sort of resolution? Are you now saying that 37mm pzgr. bursting inside of a tank would be anemic?
I’m not interested in arguing semantics; playing forum games; or lowering myself to the use of debating tactics. My intent and point in bringing the M97 to the table was to try and put some numbers to this thing. Possible fragmentation associated with a projectile with a bursting charge of weight of “X” (M97). We have another projectile (37mm pzgr) with a bursting charge weight of “Y”. Y > X so in my mind the projectile with “Y” bursting charge weight might be expected to generate as many fragments as the projectile with a bursting charge weight of “X”. This is an obvious simplification as bursting charges often employed in AP-shells consisted of higher brisance material than that utilized in HE projectiles. But this last bit only implies this mode of comparison is that much more conservative. If you have a better mouse trap for quantifying this thing than lets hear it.
This isn’t in my mind a complex problem. You have perforation fragmentation and you have bursting charge related fragmentation. Solid shot doesn’t get any bursting charge fragmentation.
Perforation generated fragmentation may be minimal for well manufactured armor – it may be as low as “one” effective fragment – i.e. the projectile itself. Ductile failure and petaling of the plate. If I have “one” effective fragment from perforation of good quality armor, and I subsequently introduce an additional 100-fragments from a bursting charge exploding, than yes the effect of 37mm pzgr is relatively speaking "highly destructive". I’d go so far as to imply that in this case it would be considered “very highly destructive”. Moreover the difference in P(k) between one fragment entering the crew compartment and 100+1 fragments entering the crew compartment is considerable.
On the other hand if the armor shatters at the point of impact into a thousand high velocity splinters -- as what apparently happened on occasion when a 2-pdr AP perforated Italian armor -- than introducing 100-additional fragments from a bursting charge detonation will not likely alter P(k) by an appreciable amount.
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Oh I get it. I got it from the start. My mind was made up sometime ago, but I see no point in continuing along with the arguing. The British had one philosophy; a number of other countries had a different philosophy. Neither is "wrong". I mean AP-solid shot will generate fragmentation upon penetration, and one doesnt have to worry about predetonation on spaced armor -- plus solid shot will perforate more armor than shell.Originally posted by John Kettler:Jeff Duquette,
Am glad that you "get it" regarding my German APHE discussion. Given some of the replies I've gotten from others, I was starting to think I was arguing in Hittite!
Regards,
John Kettler
But than AP-shell will generate the same sort of fragmentation upon penetration -- plus the shell -- assuming its bursting charge works -- will generate fragmentation(+). Moreover it gets the splinters from the armor plate spalling and perhaps the projectile nose breaking up, plus it gets fragmentation from the ass of the shell exploding after perforation.
I look at it like this: Two 37mm projectiles are fired at a target -- one AP-solid and one AP-shell. Perforation for both shot & shell generates anywhere from say 10 to 100 effective fragments from plate spalling – or whatever. And of course these are just arbitrary numbers.
Bursting Charge: If it functions following perforation even a small caliber shell will generate additional fragmentation within the confines of a tank.
The bursting charge is – as has been pointed out -- small in a 37mm pzgr. It’s only about 13grams or some such thing. But even a very small caliber HE shell like 20mm HEI will generate some 100 to 150 effective high velocity fragments upon detonation. More specific -- the bursting charge in say 20mm M97 HEI is smaller (it’s only about 8-grams) than the charge contained in 37mm pzgr. But M97 will generate on average over 100 effective fragments. I would therefore assume the 37mm pzgr’s burster could generate perhaps as many, perhaps more effective fragments as the much smaller charge in 20mm M97.
To me the math is that simple. Both AP-shot & AP-Shell get fragmentation from perforation of the plate. The AP-shell gets bonus fragmentation if the bursting charge functions. But it is not worth it to me to try and convince anyone of this. Folks are gonna’ believe whatever they want. I mean we all have to find our own way to truth.
Good luck
Jeff
Sorry -- HEI is actually M97, not M95. My bad. M95 is 20mm AP.
[ January 27, 2007, 07:25 AM: Message edited by: Jeff Duquette ]
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The Admiralty created testing criteria that was as good or better than anyone of this period. However, the test conditions were reflective of assumed battle conditions. No one was anticipating the sorts of engagement ranges seen at Falklands, Dogger Bank or Jutland.Well, yes, if you believe that fuzes are ordered into production without checking that they function properly. It would be nice to think that British defence procurement didn't do things like that, but...
Shells were being tested at relatively low obliquities. Mostly 0-degrees testing from what I have seen. This is indicative of anticipated combat ranges of 10,000yards or less. The engagements ranges in actual combat were pushing 15,000 to 20,000-yards where AP shells were plunging down at angles of 20 to 30-degrees. Shells striking heavy cemented armor components were breaking up at these sorts of obliquities. The bursting charges were either not functioning, or they were prematurely detonating before complete perforation.
But this wasn't simply an issue with British shell fire. The same sort of issues were occurring with High Seas Fleet AP-shells. It's just that those of use living in Countries where English is the primary language get exposed to more British source information. And perhaps come to the conclusion -- rightly or wrongly --that this was a problem restricted to Royal Navy shells. And of course British documentation has survived the ravages of time a bit better than German sources.
Not a big deal. My life and/or pride is not balled up into this trivia. It is more curiosity regarding how the British developed their particular philosophy on this issue.Nope, I'm afraid the Hogg piece I quoted is my only source for this (and he doesn't specifically say "trials", although I can't imagine where else "experience" would come from).There are a couple of things in the WO32 series that look as if they might be helpful, and I'll try to remember to take a peek at them next time I'm at the PRO, but that will probably not be for quite a while.
All the best,
John. [/QB]
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That somes it up pretty well. I have as yet to see a solid shot version of pzgr. for the 37mm Pak, Flak or Kwk -- aside from APCR.Originally posted by John Kettler:McIvan,
There are two basic German AP projectile types, or PzGr, with the normal one, PzGr 39, being APHE and the special one, PzGr 40 (no explosive charge, hence AP shot), being technically known as HartKern(?) which I loosely translate as being "hard kernel," AKA Tungsten, APCR or HVAP to us.
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Weapon capabilities to a great degree dictate tactics. Particularly in the sort warfare seen in North Africa between 1940 to 1943. Although I don't disagree that the contrast between AP-shell capability and AP-solid was probably not something that was occupying the thoughts of common soldiers.Originally posted by jwatts:I am more interested in real world tactics and expecially the in-game equivalents than in real world tests and statistics.
Of course rendering a tank combat ineffective would be of paramount interest to the common soldier and his leaders. And the ability of AP-shell fire to set a tank or tanks on fire has consequences that transcend the immediate tactical considerations of a small unit leader. If I win a tank battle and hold the field, I have the ability to recover and repair my own tanks – thus I can maintain the operational combat power of my formation. On the other hand if I win the same battle and hold the field, but all of my AFVs have been set on fire from AP-shell fire, I may not be recovering much of anything and my unit’s combat power dwindles. Weapon capabilities and weapon effects can therefore shape both tactical and operational aspects of war.
For the wargamer playing the one time kamakazi game in which a scenario is removed from any context within time and space, there is little interest in whether or not a tank burns after being knocked out – aside from the game graphics look ‘cooler’ if the wreck is burning and vomiting plumes of smoke. The tank is knocked out and requires no further attention. No need to consider recovery etc. The player is removed from “real world” tactical thinking.
Conversely dudes playing a campaign game might be very interested in whether a tank burns or not. Moreover a campaign game would -- in theory -- have context within time and space, and tanks that burn are not likely to be recoverable. The player doesn’t get back burned-out tanks when they fight the next tactical battle of the campaign. Their combat power dwindles.
Best Regards
JD
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Hi John:Originally posted by John Kettler:Jeff Duquette,
I suspect you waded into a thread a long time back and that I remembered at least pieces of it.
Not really -- I just recalled reading it somewhere and the memory cells told me to look in Jentz. As I say the only reason I'm here is my interest in tracing testing documents that detail side-by-side tests of AP-HE and AP-solid shot – whatever the caliber. But I see that isn't likely to occur.
The British philosophy of using solid shot AP was obviously one approach. It made sense to them based upon their own experience and presumably their own testing. Obviously a number of other Countries from the same time period believed AP-HE to be more effective in behind armor effects vs. tanks.
As far as I can tell from my own reading, the British believed their AP-solid shot could perforate more armor than AP-shell. Makes sense. And a bursting charge doesn’t do much good if the shot doesn’t perforate the target. But let’s be clear here, this design philosophy wasn’t restricted to small caliber 2-pdr AP. The British didn’t use bursting charges in either their 6-pdr or 17-pdr armor piercing ammunition. They may not have used a base charge in their post war 20-pdr APCBC -- but I am not certain about this last bit on the 20-pdr.
I think the British also believed that spaced armor used on tanks could act to predetonate bursting charges on AP-Shell and thus reduce the perforation ability of the shell against the main armor. One can’t really argue with their logic on this bit either. They conducted their own tests with their own ammunition.
Conversely a number of other countries that were producing their own armor piercing tank ammunition believed a base charge to be an advantage – even in smaller caliber projectiles. One can see the merit in this approach as well – moreover if I can get an AP shell behind the armor of my intended target, why wouldn’t it be good to have the additional behind armor effects associated with a bursting charge? Italy, Germany, Russia and the United States all produced AP-shell (AP-HE) for their tanks and antitank guns. In fact the US 57mm M86 APCBC included a bursting charge; this in contrast to British 6-pdr APCBC that did not include a bursting charge. The Russians included a bursting charge in their 57mm APBC projectiles; this in contrast to British 6pdr AP projectiles. The United States did not include a bursting charge in their 37mm M51 APC, the latter British 2-pdr marks also did not include a bursting charge. The Germans included a bursting charge in their 37mm pzgr, the Italians included a bursting charge in their 47mm AP, and the Russians included a bursting charge in their 45mm APBC; and of course we have reference to British 2-pdr AP-HE trials vs. Italian M13 suggesting that the behind armor effects of the 2-pdr AP-shell were quite good.
Anyway, I would be interested in seeing anyone produce a cite reference that details behind armor effects for side-by-side testing of AP solid shot vs. AP-shell for any caliber – 2pdr, 6pdr or 17pdr.
Best Regards
Jeff
Introduce 200 effective fragments into the crew compartment; or 
-- that's my finger on the second photo doing a highly calibrated measurement of the frontal armor thickness.
The Bouncing .50 cal - can it kill a tank?
in Combat Mission: Afrika Korps
Posted
I was of course refering to the oft quoted example of Barkmann destroying several Shermans. A damaged tank is not a destroyed one. I am not too well referenced on US losses so did defer to Zaloga's assertion. However I can categorically state that both the Wittmann and Fey claims are grossly inflated.It is striking that the high German kill rates claimed for Russia are not repeated in the West. </font>