Armor and Projectile Abbreviations

[Dan Robertson]

Re: HEAT

The HEAT effect is cause by colapsing a metal cone using high explosive. The effect is purely mechanical, the metal from the liner of the warhead moves a sufficent velocity to move the metal in the target plate as if it were a liquid. However at all times within the HEAT warheads opperation the jet remains solid.

Plasma is the fourth state of matter caused when the temperature becomes sifficently great that the electron seperate from their atoms. This is also known as an ionised gas, this generally occurs at 13000K or so or in the presence of radiation.

[rexford]

Originally posted by Kiff01:

Hello PzKpfw 1:

I'm not sure who you are referring to by ?Carey? although I have seen posts by R. Livingston. The link I posted was from a Zos. I must admit that I have seen numerous postings by members of the AFV Forum that seem less than kindly toward Lorrin's or Rexford's work. The chief complaint seems to be Lorrin's unwillingness to produce references when asked.

Hello Rexford:

Why do you suppose many of your postings on AFV News as well as other armour and tank forums generates this sort of criticism?

Cheers

This forum is not really the correct place to discuss this in depth so I will add one thing and leave the subject.

When I fully referenced my posts on AFV News they were condemned as too long and tedious, and many folks told me to confine myself to summaries.

When I summarized my work and left out the long and academic references it was condemned as being without any real support or usefulness.

I am condemned for never changing my book and then condemned by the same people in the same post for changing it.

The AFV News complaints appear to be more attitude than substance.

Lorrin

[Meach]

Damned if you do, damned if you don't..that sucks. I for one appreciate all the effort you have went to get the information and present it in a manner that I can grasp. I have learned so much about tank warfare from Rexford and I hope it continues.

Some more questions tho. On an APCBC shell I take it the AP cap is under the ballistic cap as the ballistic is there to aid aerodynamics, yeah? And the AP cap is to absorb the sudden impact to allow the penetrator to do it's job, yeah? That means the penetrator had to be of the hardest material, the AP cap slightly softer and the ballistic cap was the softest metal of all? Please put me right on this.

How did the shell "know" when to detonate upon penetration i.e a blunt nosed APBC with a high HE charge had to blow up at the right time to maximise damage, but how was this achieved?

Was the British gun shells inclusive of the shell or was it just the projectile that was measured in the weight i.e 17 pdr, 2 pdr and so on?

I would deeply appreciate any feedback on thest points.

Thanks.

[rexford]

Originally posted by Meach:

"Some more questions tho. On an APCBC shell I take it the AP cap is under the ballistic cap as the ballistic is there to aid aerodynamics, yeah?"

Yes.

"And the AP cap is to absorb the sudden impact to allow the penetrator to do it's job, yeah?"

Yes. Although armor piercing caps decrease penetration against homogeneous armor.

"That means the penetrator had to be of the hardest material, the AP cap slightly softer and the ballistic cap was the softest metal of all? Please put me right on this."

There was a wide range of armor piercing cap hardnesses, the German and Americans differed I think. The ballistic windscreen is a thin sheet metal that doesn't help or hinder penetration cause it crushes.

"How did the shell "know" when to detonate upon penetration i.e a blunt nosed APBC with a high HE charge had to blow up at the right time to maximise damage, but how was this achieved?"

The round has a given delay which couldn't have been very much if they exploded after passing through the spaced 20mm plate on the PzKpfw III front. There was about 8" (20 cm) of space to the main armor, I think. I'am not sure about the answer right now.

"Was the British gun shells inclusive of the shell or was it just the projectile that was measured in the weight i.e 17 pdr, 2 pdr and so on?"

The British used solid AP shot, then solid APC and solid APCBC. They took the HE burster out of American 75mm APCBC-HE and replaced it with an inert material (could be sand, not sure).

British AP weights for the projectile (what comes out of the barrel) are:

2 pdr which is 40mm, 2.38 pounds

6 pdr which is 57mm, 6.28 pounds

17 pounder which is 76.2mm or 3", 17 pounds

25 pounder or 87.6mm, 25 pounds (I think, but could be 20 pounds, my mind is cloudy right now)

6 pdr APCBC weighed about 7.25 pounds, including main projectile, armor piercing cap and ballistic windscreen. 17 pounder APCBC total projectile weight was 17 pounds.

[ May 03, 2003, 09:13 PM: Message edited by: rexford ]

[PzKpfw 1]

Concerning HE filler in Soviet rounds, they used a small HE cavity. The rounds had an short ogive & a blunt nose with an thin ballistic windsheild.

The Soviet rounds differed from the other nations rounds in that the Soviet rounds used grooves, located either in front of, or at the bourrelet. These grooves were described as localizers and were designed to prevent the HE filler from pre mature detonation on impact, so that the round delivered its full filler charge behind the armor in the targets fighting compartment. After WW2 the Soviets developed a blunt nosed, AP capped round with an ballistic windsheild.

Concerning German Arrowhead ammunition the German PzGr.40 APCR ammunition originaly used an solid aluminum and/or magnesium windscreen, to achieve an behind the armor incendiary effect after the round had penetrated the plate.

The reason for the use of a windscreen was because of Polte's work on shell carrier crush up. Later in the war as material shortages became prevailent the Germans used plastic or thin steel for the windscreens. The Soviets used

aluminum windscreens on some of their KE rounds.

Just as Lorrin sugests the Germans did not appreciate the performance of Russian ammo, evidence also sugests, the Soviets were unaware, of the behind the armor incendiary effect of a ballistic windsheild.

Regards, John Waters

[ May 03, 2003, 11:40 PM: Message edited by: PzKpfw 1 ]

[Meach]

Ok, starting to get all this now. The AP cap was just to crush over the penetrator, not to provide extra punch, this helped the point of the penetrator "bite" the armour. FHA, how was that created? Was it two metals rolled together in the creation process or was the face treated with chemicals? The homogenous plate I now understand is the same hardness all the way through. I am as ever, grateful for your time and patience.

[flamingknives]

FHA is a homogenous plate, where the outer layer, to a depth of a few mm, is hardened by some method. I don't know which one was used, I'm sure a WWII AFV grog will be along shortly. I'm just an engineer .

The two methods that would create a hardened face I can think of off-hand are:

* Shot-Peening. Lots of small ball bearings are fired at the plate at high velocity, these bounce off, as they're only small, but the impacts create a work hardened layer.

* Use of carbon. This is a heat treatment. The plate is heated up and carbon powder is applied to the face. The higher the carbon content of steel, the harder it is and as the carbon is only on the face, then the face is hardened while the rest remains softer, but tougher.

* Differential cooling. This wouldn't be too effective on large plates, as it would create large stresses in the plate, which would aid fracture. Basically, the part to be harder is cooled faster. This is notably used in the manufacture of Japanese sword blades, where the edge is very hard but brittle and the back edge, which is soft but tough, supports this and stops it from shattering.

[flamingknives]

If I post the same thing twice , do I appear twice as knowledgable?

Thought not.

FlamingUBB :mad:

[ May 04, 2003, 09:30 AM: Message edited by: flamingknives ]

[Kiff01]

Hello PzKpfw 1:

Thanks for the clarification. I have read many of C.G. Erickson’s posts in the past. He seems rather blunt, but I have gotten the impression he works in and around tanks a great deal. Does he work at a museum, or is he some sort of tank mechanic?

Hello Lorrin:

I received your email. Thanks. The wife got to it first and couldn’t make heads or tails out of it. She was about to delete it, thinking the various measurements references were associated with yet another penis enlargement advertisement -- junk email.

I’m not much on posting on forums, but in this case I am interested in the background of your manual Armor and Gunnery. Forgive me if I am breaching normal forum protocol. I think I might be able to manage opening a separate thread if my posts are distracting from the discussion on acronyms. “Might” being the keyword. I am still trying to figure out the system here.

I purchased a copy of Armor & Gunnery about a month ago. It’s available from the Articles of War book site. I have been taken aback by some of the posts on AFV News. Has there been a great deal of errata put out for the manual? If so, is there somewhere a person can obtain all of the errata that has been put out for Armor & Gunnery?

Cheers

[rexford]

Originally posted by Kiff01:

"Hello PzKpfw 1:

Thanks for the clarification. I have read many of C.G. Erickson?s posts in the past. He seems rather blunt, but I have gotten the impression he works in and around tanks a great deal. Does he work at a museum, or is he some sort of tank mechanic?"

Erickson welds some, and has posted pictures of himself changing the brakes on a Panther over the weekend.

"Hello Lorrin:

I?m not much on posting on forums, but in this case I am interested in the background of your manual Armor and Gunnery. Forgive me if I am breaching normal forum protocol. I think I might be able to manage opening a separate thread if my posts are distracting from the discussion on acronyms. ?Might? being the keyword. I am still trying to figure out the system here."

The book combines the research efforts of Robert Livingston and myself, which goes back to the 1960's for each person. We got together in the early 1980's and had the same interests, plus we both wargamed and used the research to perfect a very detailed wargame. Miles Krogfus worked on the same issues and we got together through AFV News, we was a very effective getogether.

We had ALOT of help from a series of folks who were mentioned in the front of the book, which includes Miles Krogfus (who has access to all sorts of German and Russian documents from WW II), John Waters and others.

So it wasn't two grogs sitting in a den thinking up fancy theories in a vacuum.

If you look at the book you'll see that we spend mucho time comparing our estimates against actual firing trials and combat reports. This isn't a selective "use the friendly stuff" kind of biased review, it includes everything we could find.

In our gaming system, which is touched upon in the book, one uses the trajectory characteristics of projectiles, the random scatter pattern and statistical methods of modeling random range estimation errors to derive where the shot goes by the target relative to where it was aimed.

If a Panther aims at the center of a Pershing profile at 1200m, our charts tell one which vertical and lateral shot scores to roll against. Which leads to a measurement as to where the round passed by the tank aim point (high or low, left or right).

Our research lead me to spend untold hours at the State Museum where they had a LARGE collection of microfiche rolls of U.S. firing trials from WW II, and we bought alot of documents from NTIS. Look in the bibliography of our book and you'll see a small percentage of the actual documents we used.

I do mathematical modeling for a living along with being a civil engineer, and we took the data and formed mathematical models. Math models for cast armor deficiency relative to rolled armor, high hardness armor relative to medium hardness, armor flaws, slope effect versus plate thickness/projectile diameter ratio, face-hardened penetration estimates, etc.

"I purchased a copy of Armor & Gunnery about a month ago. It?s available from the Articles of War book site. I have been taken aback by some of the posts on AFV News. Has there been a great deal of errata put out for the manual? If so, is there somewhere a person can obtain all of the errata that has been put out for Armor & Gunnery?"

If you bought the second edition it includes all of the errata prepared in the past. Do you want me to e-mail you the things I put together since Miles' article came out, which change some things a bit.

Things are surfacing so fast nowadays that many books are outdated while they are at the printers. Miles Krogfus' discovery of the Russian ARTKOM equation and constants completely changes the view of the published Russian penetration figures.

The discovery of the BIOS report that presents the German equation and constants for penetration at 30 degrees from normal will probably change the interpretation of the 30 degree penetration data in various books. But our vertical penetration figures for German ammo are still essentially the same as originally published.

Some of the comments about my research and posts is good and made me look further into some issues, much of it is histrionics for whatever reason.

[Andrew Kinnie]

I am looking for a way to get the Armor and Gunnery book. Is this still available someplace? I also am curious about armor penetration vs. types of armor, etc.

[roqf77]

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Pedantic mode activated

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

the Modern British HE shell of choice as its performance is not degraded by rifling spin.

Not to quibble but they actual chose the rifled barrel to fire hesh not the other way round.

(at least thats what ive been told on good authority) The british army(well ministry of defence) claims in there tests the rifled barrel actualy has superior performence to the smoothbore.

apparently i have been told the same is true of sabot ammunitiion in mod test the 120mm charms gun 's effective range is acctualy longer than the non-rifled equivelents(i think is a rheinmetal?)

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

PeDANTIC MODE TERMINATED

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Did somebody say rexford writes with a guy called livingston?

Well i belive this is an exellent website based on there work at least partly explains alot very well

http://gva.freeweb.hu/index.html

goes through types of armour and there hardness and such.

intersting information to as armour penetration of us guns were improved on the 90mm and 76mm i belive by removing the he filler and increasing propellent charge/ using a longer primer.

this is also quoted in osprey's sherman 76mm 43-65 book.

[bill clarke]

So did these rounds that entered the AFV bounce around inside or explode, or spray molten metal around ?

[roqf77]

face hardend armour was rha armour but one side of the armour to a depth of a few mm was re heat treated to toughen up one side. better info can be found on the website i have linked on a previous post

[flamingknives]

roqf77: Ways of making FHA can be found in my post further up the page. More to the point, the few mm depth is hardened not toughened. The two are pretty much polar opposites.

Bill: What the round did after defeating the armour depends on the type of round and the degree of overmatch.

AP shot: A solid round. This will punch through the plate, creating red hot splinters and other nastiness and, provided that it doesn't dig in or go out the other side, it will also bounce around a bit. Distinctly bad for a vehicle crewman's health. The amount of splinters is proportional to size of shell and thickness of armour. A 128mm shot will go straight through a halftrack, and if it doesn't hit anything important, it won't do futher damage. a 17pr shot going through an 80mm plate will make a godawful mess.

AP Shell: Also known as APHE. In addition to all of the above, a delay fuse allows the shell to pass into the tank before detonating a small explosive charge. In the confines of a tanks this can be devastating.

HEAT: Shaped charges spray hyper-velocity metal all over the place. secondary damage and heating can melt bits.

HESH: knocks bits off the inside of the tank, which then bounce around the interior and though important things.

[roqf77]

Face Hardened Armour

Face hardening (FH) is a method used to increase the armour hardness of the surface of armour plate. The rear side of the armour plate remains at its original hardness. Face hardening is carried out by taking a slab of RHA and heat treating it again, but on one side only. The heat treating is time consuming and results in a warped plate which must then be flattened in large presses. The Germans were able to handle plates up to and including 50mm thickness (with production oversizes up to 55mm), and tried 80mm FH on the early Panther glacis. Later on the Germans found a way to use a heavy electrical current flow through the steel to induction-harden one face. Both methods were used until the end of the war.

The purpose of the hardened face is to shatter an incoming projectile’s head before it can penetrate. The Germans found it resisted Soviet uncapped AP and APBC projectiles quite well, when the armour plate thickness was around the same size or not too badly overmatched by the projectile (such as Pz.Kpfw.IV 50mm front armour vs. Soviet 45mm or even 76mm AP or APBC). Britain and the USA tested projectiles against FH armour as a matter of course until about 1943, but rarely used it on production vehicles because of its relatively poor resistance to German APCBC in comparison to RHA. The Germans were faced with APC and APCBC from the Western allies only, not the Soviets, so their decision to use FH armour weakened their tanks against Western guns but strengthened them against Soviet guns.

.................................................

not me quote from website!

[flamingknives]

Aha, but you used the term 'toughen up' whereas the site uses the correct term, 'hardness'.

Toughen and harden are oppsite terms in the heat treatment of steel - during tempering as you make the metal harder, it becomes less tough and vice versa.

It may seem pedantic but:

a) I am Mr. Flamingpicky.

I am an engineer working in materials technology.

[roqf77]

oh i wasnt trying to correct you just posting what i had read on the website. Its quite good before i read i had no idea about armour barely new what rha was.

[roqf77]

didnt they stop using aphe after ww1 because it wasnt very good? i read this on one website

but im not saying its true

A.P.H.E. - Armour Piercing High Explosive

Used by most countries until about 1935, A.P.H.E. was last used by the Soviet army in 1941/1942. This type of shell had significantly lower armour penetration capabilities than A.P. solid shot. It was thought that the shell would penetrate an enemy tank and detonate inside, with catastrophic results. In reality A.P.H.E. shells shattered on impact. Low quality Soviet A.P.H.E. ammunition gave German armour a significant edge in the 1941 campaign. Some A.P.H.E. shells are tracer detonated, but most are detonated by inertia and they are used as anti-aircraft shells. Their use against tanks may have been out of accident rather than design. Navies use A.P.H.E. shells against enemy ships, and their application to tank combat may have been a throwback to this naval method

[flamingknives]

That's wrong. German 75mm and 88mm anti-tank guns used burster charges, as did the US 76mm and 75mm guns.

Only the British eschewed APHE for the superior performance at getting through the armour of AP shot.

Early Soviet APHE was low quality and also had a larger than normal load of HE, making the AP performance limited, but the behind armour effects more significant. Perhaps the website defines APHE as having a certain proportion or greater of HE.

Detonating the burster charge within a tank was devastating - look at accounts of British vs. Axis tanks in the Desert.

Beyond a certain calibre/thickness of plate, the energy released by the shell going through the plate is more than enough to wreck the tank, but this only really occurs with 75mm plus calibre and plate.

[Bigduke6]

Rexford,

I have two questions/comments on the below, but in general the stuff you are giving us is great, thanks!

First, maybe a nitpick and maybe an error on my part regarding the German vs. Soviet armor penetration dispute.

The way I read the Soviet literature, the 80 per cent success calcluation was not, as you write, a definition of penetration success 80 per cent of the time, i.e., eight out of ten rounds punching through the armor.

Rather, at least as I read it anyway, it was a definition of success if at least 80 per cent of the AP projectile made it through the armor. I realize that sounds kind of funky but that's how I keep reading it.

I'm curious about the German approach to 50 per cent success. Was it "50 per cent of the round through the armor = success" or was it "50 per cent of full penetrations?" Also if you have any comments on the 50/80 success definition issue; I think you could make me smarter.

Just curious.

Second, could you suggest a link for the Miles Krogfus' article in the May-Aug. issue of aFV News? I sure would like to read it.

Here's the text of yours I'm talking about:

"The problem is that the 166mm penetration figure for IS-2 AP is related to 80% success, and converts to 175mm at 50% success. And the homogeneous penetration of 122mm AP would be much greater than the face-hardened figure, where we estimate that 122mm AP could penetrate 201mm of homogeneous armor at point blank.

A similar calculation was made for SU 100 AP would have underestimate the ammo performance against Panther tanks.

On the battlefield, IS-2 tanks penetrated the Panther glacis at 700m.

Miles Krogfus' article in the May-Aug. issue of aFV News allows one to compute Russian penetration against face-hardened armor at 80% success, and multiplying the result by 1.06 converts to 50% success (half the hits completely pierce the armor)."