Landships II

Well done, again, Ivor. I mentioned this book here http://www.activeboard.com/forum.spark?aBID=63528&p=3&topicID=29520046 but yours is a much clearer version. (I ordered it from the library, but never heard anything)

The U.S. Tanker's helmet is on p226. More on the Swiss Leplattenier helmet, too. Several of the pics and drawings are used in Brassey's books on the British and German Armies and in Weapons of the Trench War.

Indeed it is. Have you noticed that the text says that included amongst the bullets tested on the helmet was "the Mauser bullet reversed"?

Apropos of nothing in particular, but the manganese steel as used in the British helmets (at least the version used by the Australian military WW2 and immediately after) was non-magnetic. That was a very handy property when using a compass but one completely negated if the helmet had a rim band of some other (magnetic) steel. None of those in Australian service had that band as far as I know (which is not saying much). I imagine the WW1 helmets were the same.

I didn't see anything about that that in a very brief skim of the book but the non-magnetic properties were impressed upon us when we were issued the things (only school cadets but our instructors were PMF and the training absolutely 'by the book' - or PAM). Possibly of some relevance to collectors in detecting cheap fakes.

Rectalgia wrote:

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 negated if the helmet had a rim band of some other (magnetic) steel. None of those in Australian service had that band as far as I know (which is not saying much). I imagine the WW1 helmets were the same.

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Didn't know that about manganese steel. Interesting.  The first Brodie helmets issued had a raw edge, but after it was noted that it tended to cause accidental injuries a rim of, I think, mild steel was added.

Currently reading John Glanfield's The Devil's Chariots: The Birth & Secret Battles of the First Tanks and ran across the following that made me think of this thread ...

Page 57 speaking on armored cars circa Nov 1914 ...

"The  first cars were plated in a special 8.5mm nickel chrome alloy developed by Beardmore's. It stopped an ordinary German bullet at 10yd, but if the bullet was removed from the cartridge and reinserted point first, only a 10mm plate would resist the reversed round, as the Germans were discovering."

Makes you wonder how the first reversed bullet came about, eh?

Ironsides ... great website! Will be fine addition to my reference sites. Thanks for sharing!

Cheers!

Oscar Zulu wrote:

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More on reversed bullets from John Glanfield's The Devil's Chariots: The Birth & Secret Battles of the First Tanks ... it all makes sense now, which I will explain below. ...

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Interesting - and the 'surface welding' effect may be the answer - but I remain unconvinced. I recall the 'Finding the fallen' tests involved two shots into a vertical plate. The first, with a conventional round, left a substantial dent, but didn't penetrate. But (practically) all the energy was transferred to the target - it was no glancing blow. The second shot, with the reversed projectile penetrated completely and it was no sub-calibre hole, or at least not noticeably so. (The armour was, I think, 6mm 'replicated' plate - after metallurgical examination of a sample of the original - not 8mm but still ... the difference in non-penetration/penetration was clear.) Somehow that second shot picked up additional energy. That had to occur in the firing chamber and/or barrel (I can't see it happening at the target - momentum is conserved). As commented elsewhere, my bet is on the chamber, additional pressure somehow occurring (the blunt-nosed projectile bearing on the lands of the rifling or compression of the powder charge perhaps).

A theory based on two shots isn't much to go by, admittedly. But then there are the 'laws of physics', conservation of momentum in particular. And other reports. Stepping aside for a moment, I suppose there could be some sort of 'pressure-pump' effect at the momentarily molten or plasticised impact point - but that seems to be getting a little away from 'the known'.

Generally speaking (I come back to it) penetration is very much about velocity. EFP's hit with something like 2,000 m/s velocity. Shaped charges more like 8,000 m/s. A little 75 grain .243 projectile at 1,000 m/s will (reportedly) punch straight through Ferret side armour when a 174 grain .303 at 750 m/s will just bounce off it all day long.

For me it remains a bit of a puzzle.

-- Edited by Rectalgia on Sunday 24th of January 2010 07:57:41 PM

Brennan wrote:

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...With such an effect the other speculatve option is that the bullets lead core might immitate a "self forged fragment"???? Thus heat, density & retained velocity on a smaller surface area magnify the penetrative effect.

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Yes, that sounds feasible, thanks for the suggestion. I was reaching/struggling for that concept with the "pressure pump" thought - how to retain penetrative velocity without abrogating 'conservation of momentum'. My frustration with the 'sticky impact avoiding deflection' explanation is that it is superfluous to any description of observed increased penetration for a flat, 90 degree impact (not to mention the absence of penetration by a normal round in comparison). The (pretty much) full-calibre hole would not rule out penetration by a sub-calibre fragment - the whole impact area of the armour must be fluid with such a type of penetration so the dynamics are a little like a water drop falling onto the surface of a pool, or a major meteorite striking the Earth's surface - indeed the raised crater rim on the impact side of penetrating shots reinforces that imagery.

As you suggest, there is no need for any of this to be mysterious - commentary on a great many trials is out there somewhere. I always think of Jules Verne's description of the 'arms versus armour' race in "From the Earth to the Moon" as an illustration of just how much work was done, even in the relatively peaceful 19th century (well, once l'empereur Napoleon was out of the way, the Crimea, etc.) - and how much more when the pace quickened. But, a note of caution, physics in general and ballistics in particular, are surprisingly prone to fads and 'preferred explanations' which can linger in 'received/popular wisdom' long after the foundations are convincingly refuted. The later availability of ultra-fast imaging and extremely accurate non-contact chronography might call for some re-trial and re-interpretation.

I suppose if we have a resident fan of the "Mythbusters" it could be put to them to revisit the phenomenon. But I am not a great believer in their attention to detail/methodology, nor in their safety (I still shudder to recall that girl in the "Exploding Trousers" episode 'carefully' cutting the brass studs off a pair of overalls already impregnated with sodium chlorate/sodium perchlorate, or similar, and dry). It goes without saying that initial investigation should involve fully-serviceable military Mausers of the era (for chamber tolerances etc) and close replicas of the WW1 8x57JS cartridge in terms of propellant type and quantity and of course projectiles - and various seating depths. And remote firing, at least of the of the reversed projectiles and any other rounds in terms of non-standard bullet seating/crimping.

Whatever - I think I shall be enjoying a spot of spare-time research into the published materials, as you suggest.

Thanks for that - all noted.

From - www.greatwarcollection.nl/Html/Brodie.html

"The British helmet contains 12% manganese steel, the American 13%"

At that % of Mn the helmet could probably be cold pressed in a single operation. I'd guess
the German practice of cold pressing in multiple operations was to form the steel without causing tears - Ni/Cr alloys are more brittle than Mn steels.

Regards,

Charlie

All interesting, thanks.

Re AP bodkins - I thought the Royal Armouries research (though limited) was interesting too - Armour-piercing arrowheads - of course the mild steel bodkins would be quite adequate against cheaper armour and at considerable ranges too (the statutory minimum archery practice distance at one time was a furlong). But I digress ...

-- Edited by Rectalgia on Monday 25th of January 2010 07:04:17 PM

Hi Brennan I dont think AP rounds were rated very highly before WW1 all the reports Ive seen seem to suggest that most would fail the test described in one of the patents, ie a shell is supposed to penetrate its calibre of armour, most seem to have caused damage by shock effect rather then penetration, but then this is for naval guns where you have very heavy shells rather then bullets...

Getting back to body armour this might interest...

http://www.flickr.com/photos/glosters/2222399803/

It seems that the fairly light weight armour was often privatly bought by soldiers or their relatives and saved many of those who wore it, but then my guess would be this was from Low velocity missiles.... shell fragment, shrapnell ,ricochets, spent bullets or those at very long range etc

Cheers

There is a bidg debate in America on AP Vs Round shot. AP does puncture surprisingly well - Friend off mine corrupted me into 19th Century naval so some where I have a file on penetration data. The round shot produces "racking" which strees the whole structure of the armour & its supports.

The basic reason the debate is confined mostly to the USA is the vast diference in building techniques between the US & Europe, particularly Great Britain plus the size. Most US initial experience is on relatively small vessels & on converted vessels so great shock could be effective. On large purpose built vessels (even if wooden hulled & then armoured) this simply did not work! It was a falicy to attack just the armour not the ship.

The next trick  is the nature of the target e.g. a standard British 6" armoured target was the following sandwhich; 6" or armour, 18" to 36" of Teak Or Iron Pitch (as a compressable material), 1" to 3" of Wrought Iron or Steel Hull
 & finally 12" to 18" of Teak as interior backing. Iron pitch was a dense mixture of of Iron fillings & swarf in with pitch & rubber, the whole mixed hot & compressed. The Armour actually being only approx half the resting power of the whole that was 3 feet to 5 feet thick!

There is a return of trouble in the late 1870's & into the 1880's particularly with AP shell (often called Palliser). The issue was that AP shell detonated its charge by shock compression of the black powder filling - using a conical cavity in the shell. Here as the sheel slowed on striking armour the powder pressed into the conical cavity under it's own inertia - thus detonating. The problem was that detonation occured too fast, often at partial or just penetration so directed the charges force back out through the penetration hole.

As steels & steel armour etc impove the whole reduces involume, plus gun velocities & lenghths increase too.

If people are intested I will locate the data that he & I found at our peak interest.

Brennan

Brennan wrote:

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The issue with soft caps is they especially assist penetration of face hardend armours!

Cold caps aid particularly penetration of hommogenous armours, but have a real risk at high velocities of breaking the point or shattering on face hardend armours.

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Precisely what Douglas T. Hamilton (American) says in High Explosive Shell Manufacture (1916) which is especially interesting in dealing with British, French, Russian and Serbian projectile design and manufacture, as well as U.S. types. So much to learn, so little time - I downloaded the .pdf version well over a year ago but obviously haven't read it through yet.

I'm wandering off topic again. Perhaps Hamilton's other book on Shrapnel Shell Manufacture (1915) might help atone by being a little closer to the subject of body armour and helmets.

Glad if I have in a small way repaid the knowledge you guys have shared and the patience with which you have done it. The archive.org "American Universities" resource is magnificent but I confess I haven't quite mastered the art of trawling it.