Armor Penetration and Armor resistance.

[Dan Diffendale]

Lastly, I had trouble posting to this thread earlier and opened a parallel one with some lengthy posts, with a request to a moderator to move them across to here

Unfortunately, the board software doesn't work like that -- but you're welcome to copy and paste your stuff into this thread... and then the other can be locked and deleted.

[hoplite14gr]

Paul agree with wou on sling bullet flesh penetration.
As I posted before a good shot and they can even cruck bone under armor like a mace.

on sling range:

Xenophon "Anavasis" 3 2 16
"Kai to loipon tês hêmeras hoi men eporeuonto, hoi d' heiponto kai ouketi esinonto hoi barbaroi têi tote akrobolisei: makroteron gar hoi te Rhodioi tôn Persôn esphendonôn kai tôn toxotôn "

Just the bold means:

Longer than the Persians and the archers slinged the Rodians

which means that Rodians slnged longer that Persian slingers of Tissafernes amd the Greek Cretan archers (implied) or else he wouldn´t have mentioned them he would have simply wrote

"makroteron gar hoi te Rhodioi tôn Persôn esphendonôn" which means that Rodians slinged further than (all) Persians (that would include both archers and slingers)

Kind regards

[Paullus Scipio]

Thanks, Giannis, but I am still not convinced your translation is correct - though I hasten to add I am no Greek speaker, either classical or modern!

It seems to me you have taken the original greek phrases out of order, to arrive at your suggested meaning. This may be due to the difficulties of translating twice - classical greek to modern greek to English !!
The translations I have read "....could sling further than the persian slingers, and even further than most of their archers." (Rex Warner, Penguin edition) and "....carried farther with their missiles than the Persians, farther even than the bowmen." (Carleton Brownson, Loeb edition ) seem to me to be more accurate.
Would anyone with a better Classical Greek than mine care to comment ?

Thank you also Giannis for pointing out that the Persian slingers were stone- armed. Xenophon specifically remarks on their large size at iii.17.
But just to muddy the waters, shortly after the passage under debate, Xenophon says "A number of bow-strings were found in the villages and some lead also which could be used for the slings." So the Persians certainly had lead available to them, if they chose to use it.

[Paullus Scipio]

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Posted: Wed 30 May 2007, 17:38 Post subject: Armour pentration and Armour resistance

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I am posting this on a new thread, because for reasons unknown the thread of this name seems to be closed.
Could a moderator look into this, please, and then transfer this across?

Following on from my earlier post, and keeping in mind that kinetic energy and momentum are the key , but not the only, factors that defensive armour has to defeat we can move on to a detailed study.
First, some important notes so that we don’t get too carried away with what is for many, a fascinating subject.
• Since the dawn of time there has been a constant duel between armour/weapons, that is still going on today. From time to time, one or the other gains the advantage (e.g the rise and domination of armoured infantry in greek/roman times, the era of the longbow/crossbow, the brief reign of ‘hardened’ plate , which I guess is the subject of Alan Williams “The Knight and the Blast Furnaceâ€

[Paullus Scipio]

By way of contrast to the above figures, here are some which I think come from Alan Williams "The Knight and the Blast Furnace".
Alas, where they are quoted no context is given and as we have seen, that makes all the difference.

5mm cuir-boulli requires 20 joules for spear/lance to penetrate, or 50 joules with a blade stab.90 joules for a sword cut/slash
10 mm cuir-boulli, increased to 30 joules for spear/lance and 90 joules for blade stab.
!.9 mm munition plate ( i.e. not especially hard ) 100 joules for spear/lance, 190 joules for blade stab
mail - 120 joule to pierce
Layered linen ( in view of Dan Howard's posts, presumably loose /quilted and not glued ?? )
5 layers -100 joules
9 layers -120 joules
16 layers- 140 joules
23 layers- 160 joules
26 layers -180 joules

There seems to be something suspiciously high about the latter figures, and Williams has been criticised for being "armour biased" and under estimating weapon force and kinetic energy ( but I believe most estimates/trials/calculations are probably too high for real battle conditions.
Perhaps Dan and others with access to this source can elaborate for us ?
What were the conditions of these figures? Practical tests ?( and if so, quasi static or dynamic or both ) Calculated/estimated ? ( if so, then to be treated with great caution ).
If the figures are appropriate, then the ones for linen give food for thought.
If hoplite tube-and thorax corselets were made of this, then in the light of Blyth's figures, the protection was way more than adequate, and there would have been no need to re-inforce them with scales etc against Persian archery. Similarly, if linen was this effective, then given its other advantages ( lightness etc ) why was it not more widely used ??

We need to know more !
_________________
"dulce et decorum est pro patria mori " - Horace, ODES
(It is a sweet and proper thing to die for ones country)

"No son-of-a-bitch ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country" - General George S. Patton

Paullus Scipio/Paul McDonnell-Staff

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Sean Manning

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Posted: Wed 30 May 2007, 19:02 Post subject: Re: Armour pentration and Armour resistance

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Paullus Scipio wrote:
By way of contrast to the above figures, here are some which I think come from Alan Williams "The Knight and the Blast Furnace".
Alas, where they are quoted no context is given and as we have seen, that makes all the difference.

5mm cuir-boulli requires 20 joules for spear/lance to penetrate, or 50 joules with a blade stab.90 joules for a sword cut/slash
10 mm cuir-boulli, increased to 30 joules for spear/lance and 90 joules for blade stab.
!.9 mm munition plate ( i.e. not especially hard ) 100 joules for spear/lance, 190 joules for blade stab
mail - 120 joule to pierce
Layered linen ( in view of Dan Howard's posts, presumably loose /quilted and not glued ?? )
5 layers -100 joules
9 layers -120 joules
16 layers- 140 joules
23 layers- 160 joules
26 layers -180 joules

There seems to be something suspiciously high about the latter figures, and Williams has been criticised for being "armour biased" and under estimating weapon force and kinetic energy ( but I believe most estimates/trials/calculations are probably too high for real battle conditions.
Perhaps Dan and others with access to this source can elaborate for us ?
What were the conditions of these figures? Practical tests ?( and if so, quasi static or dynamic or both ) Calculated/estimated ? ( if so, then to be treated with great caution ).
If the figures are appropriate, then the ones for linen give food for thought.
If hoplite tube-and thorax corselets were made of this, then in the light of Blyth's figures, the protection was way more than adequate, and there would have been no need to re-inforce them with scales etc against Persian archery. Similarly, if linen was this effective, then given its other advantages ( lightness etc ) why was it not more widely used ??

We need to know more !
Williams' figures were based on experiments. Unfortunately, he is often a bit vague about the details of tests other than the world-class ones he did on metal plate.

Williams tested a 32-layer linen jack section with a density of about 1 g/cm^2- this is heavy, so apparently it was densely stitched, heavy linen. Those figures are how many layers were penetrated at a given energy, which is different from how much energy would be needed to penetrate as many layers by themselves. I think the test was with a blade rather than a spike or point, but can't find my notes.

Williams' figures for jack penetration fit a very nice linear curve, with each layer absorbing about 4 J. I think they are accurate, but high end. I think it would be easier to penetrate a ten-layer jack of a given cloth than to cut through ten layers of a twenty-layer jack because the back layers add "give" and reinforcement.

Linen was widely used! In the middle ages after AD 1000, for example, cloth armours were the standard medium-cost equipment of common soldiers. Cloth armour is not, as far as I know, lighter than plate armour giving similar overall protection.

I'm not sure if scale-reinforced armour was a reaction to Persian archery as Blyth suggests. It might have been fashion, or inspired by desire for better protection from spears. I haven't read his thesis.

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Paullus Scipio

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Posted: Wed 30 May 2007, 22:33 Post subject: Armour penetration and Armour resistance

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A most enlightening post, Sean.
Judging by Blyths figures,see above, the difference in force between a stab with a spear and a sword are not great, but Williams shows that the energy required to penetrate (which is not the same thing as Blyth was measuring ) has significant differences.
The rather high figures he gives for the Jack would be consistent with his other tests if made with a blade.
And you make two further good points - textile armour is not necessarily lighter than metal for a given level of protection, and use of textile (and leather for that matter ) was widespread in the Middle ages.
I was however thinking more of Graeco/Roman times - the use of textile/leather armours, even in Hellenistic armies, dies out shortly after mail appears which might seem unlikely if a multi-layer Jack offered such good protection as the raw figures suggest. But judging by Williams other figures, it would appear that a lower energy would be required from a spear/javelin, and much lower still from an arrow.
We should also remember that 'effectiveness' is not the only, nor even the main criteria for choosing armour.As you have pointed out, even fashion can be a criteria.
However, in the case of the tube-and-yoke corselet, the scale re-inforcements can hardly be as a reaction to spears, which had been around for a long time and which the 'Hopla' had evolved to resist, and it is stretching co-incidence that the scales appear around the Persian wars, particularly in Attic pottery and die out shortly after them. While they might be a fashion, copying asiatic enemy styles, it is surely stretching co-incidence again that scales very effectively increase resistance to arrows?
_________________
"dulce et decorum est pro patria mori " - Horace, ODES
(It is a sweet and proper thing to die for ones country)

"No son-of-a-bitch ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country" - General George S. Patton

Paullus Scipio/Paul McDonnell-Staff

[geala]

Hmm, Paul, a very good summary of the performance of Greek ancient arms and armours. I will save it on my hard drive to have it at hand even after the death of the www.

I would not say that textile armour died out. In Sekundas "The Ptolemaic Army" some examples of 3rd and 2nd century BC cloth armours are given for example. The use of mail may be also connected with the "winner and ruler" image of Rome, not the pure performance of the equipment.

[Paullus Scipio]

Thank you Wolfgang !
Yes, as I pointed out, "effectiveness" is not the only or even most common reason to adopt a particular type of equipment.
Probably 'die out ' is too strong a term - for all we know the last ptolemaic army may have included leather/textile armour in its battles with Caesar !
But the implication of the Alexandrian tomb paintings and literature is that "roman style" equipment and armour largely replaced other types........

[Merdolino]

5 layers -100 joules
9 layers -120 joules
16 layers- 140 joules
23 layers- 160 joules
26 layers -180 joules

this have no sense, if 5 layer is 100J if you ad 4 layers you ad 20 joules.

[Dan Howard]

There is a cushioning effect as well. The more layers you add, the less this effect has as a percentage of the total number of layers. It is more evident when you compare these results with his other test involving textile armour. There is not a straight linear progression between the number of layers and the amount of damage the armour can resist. Underpadding (either a padded liner or separate subarmalis) has a far more important role in the ability of body armour to protect the wearer than many people suspect.

[Merdolino]

Yes, but even think 5 layers of linen stop 100J arrow, how is possible? an arrow with 45J can pierce 1mm middle steel.

[Dan Howard]

I've just reread the relevant section. The figures given for the above linen test are for a simulated blade edge, not a point. In another test it only required 50J for a lance point to compromise 16 layers of linen. He never tests a bodkin point against a textile target.