Sloped armour

[Gavin-Phillips]

I watched a short youtube clip recently and was somewhat amused to learn that "the T-34 pioneered the use of sloped armour.." when its pretty evident that earlier Soviet tanks such as the BT-7 fast tank and later versions of the T-26 infantry tank featured at least some sloping in their armour - mostly on their turret and hull fronts.

 

There may well be a difference for who invented the idea of sloped armour to those who actually fielded it first; so I guess both would be acceptable answers.

 

Thanks

Edited January 30, 2008 by Gavin-Phillips

[philgollin]

One needs to look at it carefully.

 

IF one looks at naval armour you will see "sloped" armour way back in the mid-19th century (floating batteries and some monitors) - but that was for deflection rather than deliberately used to both lengthen the effective armour length and cause the shell to impact at a more oblique angle. (And of course deflection slopes to fortifications and even earlier wooden vessels were around).

 

The first major ship I know about which had a deliberately sloped armour (as opposed to armour contoured to the hull and may have had a slpe as a consequence) was HMS Hood - BUT I am sure she was not the first, one probably wouldn't try out such a step with such a large ship.

 

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[cbo]

I watched a short youtube clip recently and was somewhat amused to learn that "the T-34 pioneered the use of sloped armour.." when its pretty evident that earlier Soviet tanks such as the BT-7 fast tank and later versions of the T-26 infantry tank featured at least some sloping in their armour - mostly on their turret and hull fronts.

 

It is an often repeated and as you say, wrong, assumption that the T-34 was the first AFV with sloped armour. Just look at the French FCM-36 from the latter half of the 1930ies, which has sloped armour just about everywhere. German armoured cars also sported sloped armour in the 1930ies and so forth.

 

There may well be a difference for who invented the idea of sloped armour to those who actually fielded it first; so I guess both would be acceptable answers.

 

As for the invention of sloped armour, I seem to recall that idea that obliquity increased protection was known in the late 1900-century with regards to naval gunnery. Dont know to which extent they acted on it in ship design, but the principles involved was known.

 

It may be debatable to what extent early tank designs used sloped plates to increase protection or just as part of the design. Look at the German WWI tank, the A7V, for example. They could've built a box on tracks, yet the sides a slightly sloping and the nose is pointed:

 

 

Was it done to increase protection or just because it was practical for some reason?

 

cbo

[Vasiliy Fofanov]

It is an often repeated and as you say, wrong, assumption that the T-34 was the first AFV with sloped armour. Just look at the French FCM-36 from the latter half of the 1930ies, which has sloped armour just about everywhere.

 

Not only that, but T-34 actually *was* inspired by FCM-36. But at any rate, this is *far* too late a time frame to look for first sloped AFV. One needs to look many centuries back, to Leonardo da Vinci design, which really got *everything* wrong *except* for the sloped armor

[Siddar]

My bet would be on navy being the first to knowly use sloped armour by design against canon fire.

[Archie Pellagio]

Wouldn't the low, sloping walls to defeat gunpowder arty count?

[DKTanker]

Wouldn't the low, sloping walls to defeat gunpowder arty count?

I would think at least that far back...further if one looks at some fortifications that used sloped and rounded features to mitigate the effects of seige weapons (read trebuchets and the such) upon their walls. Also as Jason stated, personal armor to include shields and plate armor were curved (sloped)to help parry blows and the such.

[APF]

I would think at least that far back...further if one looks at some fortifications that used sloped and rounded features to mitigate the effects of seige weapons (read trebuchets and the such) upon their walls.

 

Not so sure about that: while the slope of a tanks armor serves both to deflect the misslie and increase LOS armor thckness, medieval round turrents were round because the shock of impacting missiles and rams was better distributed to the wall on the left and right of the point of impact.

 

Greetings

[DB]

"Warrior to Dreadnought" notes that the "Coles Cupola" had sloped sides, dated 1861, although later cylindrical turrets were used.

 

Then there's Merrimac.

[Vasiliy Fofanov]

Well if you want to go back THAT far

 

I don't see why not, the principle didn't change in the slightest...

[Blunt Eversmoke]

1915, Mgebrov armored car. Sloped armor concept taken to the extreme.

 

[Gavin-Phillips]

I do recall seeing a few sketches of an "armoured car" designed by Leonardo daVinci. From what I recall of it; it was a very rounded almost saucer-like shape!

 

I do recall back in high school learning about castles how originally stone buildings had square turrets - but direct hits by large rocks flung by seige weaponry would break these apart pretty rapidly. Rounded turrets tended to deflect the shots far more effectively so these became the standard.

 

More early sloped armour examples would of course be the ironclads, made somewhat famous by the semi-fictional CSS Texas in the movie "Sahara".

 

I think I should atl east try to keep myself on the subject of sloped armour on tanks though WW1-era rhomboid tanks seem to have sloped armour on the lower hull front although I have my doubts about this being anything to do with shot deflection - rather a shape which assisted the vehicle being able to cope with the steep slopes of anti-tank ditches.

[jwduquette1]

CSS Virginia

 

[Przezdzieblo]

Helepolis, 305 BC

 

 

Question is when slope is present because of need of increasing ricochet probability and basis thickness (and here, for significant advantages 30-45o from vertical might not be enough), and when is just a matter of construction (could ever CSS Virginia/Merimack float with vertical armor?) or weight savings. Pyramid are sloped not because those were supposed to be better protected

[Vasiliy Fofanov]

could ever CSS Virginia/Merimack float with vertical armor

 

Umm what's the difference? Sloped armor weighs mroe or less the same as vertical of the same LOS thickness

[Przezdzieblo]

I guess the real difference would be in metacentric height

[philgollin]

Umm what's the difference? Sloped armor weighs mroe or less the same as vertical of the same LOS thickness

 

Going back to post 3 :-

 

"........ IF one looks at naval armour you will see "sloped" armour way back in the mid-19th century (floating batteries and some monitors) - but that was for deflection rather than deliberately used to both lengthen the effective armour length and cause the shell to impact at a more oblique angle. (And of course deflection slopes to fortifications and even earlier wooden vessels were around). ...."

 

The earlier useage seemed to be more for "deflection" rather than the later specifically designed use of slopes as a way of increasing both the effective length of the armour and the angle of incidence.

[Exel]

It may be debatable to what extent early tank designs used sloped plates to increase protection or just as part of the design. Look at the German WWI tank, the A7V, for example. They could've built a box on tracks, yet the sides a slightly sloping and the nose is pointed:

 

 

Was it done to increase protection or just because it was practical for some reason?

 

cbo

 

The sloping is too insignificant to really improve protection, so my guess would be that it was done to save weight and quite possibly to improve stability as well. Sloping the side walls reduced the size of the front and rear walls, therefore saving on total armor mass. Using a 'pyramid' shape also brings the center of mass lower so the box is more stable and wont fall to its side so easy.

 

The question is which tank first used sloping deliberately as a means of enhanced protection?

[cbo]

The S35 and then the T-34 are merely the two tanks that most rigorously applied front and side sloping protection.

 

Why single out the Somua S-35? The nose was rounded, while the drivers plate and hull and turret sides were sloped at a mere 22 degrees. That is about the same as the Hotchkiss H35, also from 1935 (drivers plate more vertical but otherwise...).

 

German armoured cars, like the SdKfz 221 from 1935 or the SdKfz 231 (6-rad) from 1932 were far more radical in their use of sloped armour, as it was both more sloped and rigorously applied to nearly all surfaces. I'd argue that the Germans were the first to use sloped armour deliberately to increase protection of an armoured vehicle. It is most prominent from 1932 with the Büssing SdKfz 231 (6-rad), but you can find the same principles applied in the 1930 6-rad based on the Mercedes and to a lesser degree in the Kfz 13 and 14 armoured Adler 4x2 cars, also from 1932.

 

Whe it comes to tanks, the FCM-36 was from 1935 like the Somua, but used a much more radical scheme of sloped plates on all surfaces. The Renault ZM from 1934 also seems to have made deliberate use of sloped armour, with a long, nearly horizontal nose leading up to a sloped drivers plate with sides sloping both back and inwards.

 

The Somua wasn't first and the use of sloped armour wasn't particularily rigorous compared with other French designs from the same period. And the German armoured cars were both earlier and more radical in their use of sloped armour.

[cbo]

double post

Edited February 1, 2008 by cbo

[Arminius]

I am quite sure, the T 34´s impression on the Germans was because of its COMBINATION of sloped armour and a DIESEL motor ( along with a powerful gun ), which, when coupled with wide tracks and a good suspension gave good speed on any ground, and superior range and a little less burning risk.

 

The sum was more than the sum of its parts.

 

H