sherman jumbo

But Churchill front full was 150mm, not 102mm. The BHN of plates of differing thickness will be somewhat different.

No i'm not. Reread my post.

 

"British armour specifications are expressed more generally than for other nations. They were actually based on resistance to penetration tests and the BHN was only a rough check to determine that the armour plate met an approximate standard. For example, I.T.80 referred to 80mm of armour plate which was able to resist the 2-pounder AP projectile. Any suffix letters (I.T.80C, I.T.80D, I.T.80E) referred to adjustments to that standard. The exception to this is the I.T.110 specification, which was insufficiently alloyed to allow hardening at more than about 35mm thickness, so this designation is a bit of a mystery.

It isn't possible to specify the armour hardness by year and thickness as with other nations. Instead the British vehicle armour data tables make use of several symbols (such as “ § ” and “ ¶ ”) to differentiate between armour specifications. These symbols are then used in the Vehicle Armour Hardness table to determine the BHN."

As it 90 is for all cast armour it is accurate to qoute this bhn for the churchill tank.

Britain instead used the Izod Impact Test

A test specimen, usually of square crossed
section is notched and held between a pair of
jaws, to be broken by a swinging or falling
weight. When the pendulum of the Izod testing
machine is released it swings with a downward
movement and when it reaches the vertical the
hammer makes contact with the specimen
which is broken by the force of the blow. The
hammer continues its upward motion but the
energy absorbed in breaking the test piece
reduces its momentum. A graduated scale
enables a reading to be taken of the energy
used to fracture the test piece. To obtain a
representative result the average of three tests
is used.(http://mdmetric.com/tech/metalsglossary.htm)
.

Brinell hardness
The hardness of a metal or part, as represented by the number obtained from the ratio between the load applied on and the spherical area of the impression made by a steel ball forced into the surface of the material tested. The Brinell Hardness Number (BHN) is determined by measuring the diameter of the impression using a low power microscope, then matching this diameter with the load on a standard table.

the i zod test is actualy a represention as the amount of pressure required to break the armour.

 

"But Churchill front full was 150mm, not 102mm. The BHN of plates of differing thickness will be somewhat different. "
no it doesnt. read the website. british cast armour between 31-160mm have a bhn of 293-332.

 

You stated and I quote:

You also stated that this was from an official WWII office file. That website, however, contradicts this "official WWII office file." The website, therefore, must be wrong. It is not a good debate tactic to submit two contradicting sources, and then change your stance to support either one when it is more convenient for you.

It is also not a good debate tactic to break up a single potential post into several posts to attempt to intimidate your opponent through sheer numbers of posts.

The fact is that British BHN cannot be preciesly measured and you have not submitted a source for your claims other than a website that pretty much says the same thing.

 

http://63.99.108.76/forums/lofiversion/ ... t2248.html

"Armor resistance is based on T/D ratio, flaws, cast deficiency relative to rolled armor and high hardness resistance reductions when projectile diameter is larger than armor thickness. T34 45mm plate is over 400 Brinell Hardness, and will lose 24% of resistance when it is hit by German 75mm APCBC."

On the issue of t-34 armour quality.

 

your not reading what im posting. and im not trying to offend you. The website and my source do not contrdict each other. your just not reading it well.
It is very clear, besides they both support each other so your point is strange.

It says very clearly that the bhn is linked to the it of the plate. but all cast armour equals onw it plate number, therefore there is not impossible to calculate bhn of the armour.
i posted what the website says in more detail, it does not say it is impossible to calculate the bhn. it gives a link to a better description, i believe i qouted it for you.
If not click it and read it, it explains it very clearly.

Note my source said essentialy the same not exactly.

 

Besides that comment is refering to rha.
AS "Specification I.T.90 for cast armour of all thicknesses2
There is no difference in resistance of cast armour, as all thickness meet the same standard and have the same bhn.

ill qoute it again.
"Armour Specifications
British armour specifications are expressed more generally than for other nations. They were actually based on resistance to penetration tests and the BHN was only a rough check to determine that the armour plate met an approximate standard. For example, I.T.80 referred to 80mm of armour plate which was able to resist the 2-pounder AP projectile. Any suffix letters (I.T.80C, I.T.80D, I.T.80E) referred to adjustments to that standard. The exception to this is the I.T.110 specification, which was insufficiently alloyed to allow hardening at more than about 35mm thickness, so this designation is a bit of a mystery.

It isn't possible to specify the armour hardness by year and thickness as with other nations. Instead the British vehicle armour data tables make use of several symbols (such as “ § ” and “ ¶ ”) to differentiate between armour specifications. These symbols are then used in the Vehicle Armour Hardness table to determine the BHN."

Note the only armour with identifying symbols are rha. the churchill used cast armour.

 

Excuse me, but didn't all this start with a question over wether or not the Jumbo's armor was as effective as the Churchill's? Didn't both of you agree they were essentially the same?

 

canambridge. yes it did.
Im not trying to flame mr philips. Or indeed insult his intelligence. We are just having a general discusion. it has gone off topic somewhat, but im just trying to explain my position.

 

Why oh why does every new guy call me Philips?

Whatever, i'll concede since this has gone way over my head by now.

 

sorry misread your name!

 

A Jumbo is up armoured sherman however it was too heavy for the transmission(sp?)