Re: Muslim Cannons at Capture of Constantinople

On Fri, 12 Dec 2008 12:05:50 GMT, Vince <firelaw@xxxxxxxxxx>
wrote:

Peter Skelton wrote:
On Thu, 11 Dec 2008 22:15:46 GMT, Vince <firelaw@xxxxxxxxxx>
wrote:

Peter Skelton wrote:
On Thu, 11 Dec 2008 19:10:37 GMT, Vince <firelaw@xxxxxxxxxx>
wrote:

Andrew Robert Breen wrote:
In article <b8g2k4l0lfs4661rfne26snv5ifgjj97l0@xxxxxxx>,
Peter Skelton <skeltonp@xxxxxxxxx> wrote:
On Thu, 11 Dec 2008 16:29:31 GMT, Vince <firelaw@xxxxxxxxxx>
wrote:

Andrew Robert Breen wrote:
In article <ghr4mc$omj$1@xxxxxxxxxxxxxxxxxxx>,
William Black <william.black@xxxxxxxxxxxxx> wrote:

By the way,the balls were hand made from marble, they've got a couple of
them lying about as well...
I seriously doubt they would use marble if granite is available

Granite is both harder and denser

And harder is a advantage working with hand tools?
Guns of that nature did their damage by sheer KE delivered.
The key is "delivered" a water balloon often shatters and splashes when
it hits a window when a stone of the same mass and velocity smashes the
window nicely
hardness and toughness , as in AP shell give you a concentration at the
point of impact
a battering ram or bombard crushes the stone at the point of impact
that is why you put a big bronze head on the battering ram
mass alone won't do it.

you cant break up concrete with a wooden mallet no matter how massive
an iron pick does just fine


Penetration
in the sense of a modern shell wasn't what did harm, it was the impact
causing structual failure of the target supports
no, its crushing of the surface

<s>

Complete and utter nonsense. The objective is to form a breech.
That's done by displacing blocks, forming cracks in the
structure. Crushing the surface is counter-productive because it
reduces both the energy and impact the general structure has to
handle.
nonsense yourself

Walls are very very thick and composed of large stone
In siege warfare in that era you crush the stone
you cant displace block in a thick wall, it has nowhere to go
crushing is a cracking process
you induce cracks by impact, the debris falls out


I'm not going to debate the engineering facts of life with you,
but you might think about th3e nonsense you just posted in the
context of adjoining blocks cracking with the impact.


Peter Skelton

you wrote "it was the impact causing structural failure of the target
supports"

The hell I did.

then you say "displacing blocks forming cracks in the structure"

Right

These are simply not equivalent

What was your first clue?

You may be thinking of a thin wall (i.e. ratio of height to thickness of
3 - 1 or more , such as the walls of Rothenburg

it makes a big difference how thick the wall is.

Try the following experiment

take four hundred solid concrete blocks 1 x 1 x 2 meters and
make a wall four meters high and
4 meters thick by interlocking courses (blocks are all perpendicular by
layers

now punch a hole through the center of the wall with a solid ball

Not someting remotely relevant with the technology we're talking
about

What do you want your ball made out of ?

hard and tough or soft and frangible?

As a practical matter it depends on the mass of the ball the impact
velocity and resultant deceleration

if you could fire the ball fast enough to overturn the wall or move the
blocks an inelastic collision might be superior, e.g. a crushable ball

But if you can't, you want to crush the surface of the block and open a
"hole " into which the upper blocks will fall for that you want
something very hard and tough since you have to chew through the
material If the blocks are smaller the crushing action can crack the
individual block. In that case you crack the block and the debris falls
out Siege gunners created a characteristic V shape opening by moving
impacts down the wall as the blocks cracked


This is not a case of hard good/soft bad. There will be a best
choice which will not be the hardest ball, even not allowing for
manufacturing.

There will be a momentum/impact transfer between thye ball and
the wall. What is wanted there is the maximum transfer to the
wall because the foundation of the wall won't move but individual
blocks must, ignoring the elasticity of the blocks. That causes
some of the energy of the ball to cause cracking of the block hit
and adjacent blocks which is what you want. The rest goes into
crushing the imact area and the ball which aren't bad things but
aren't as useful.

Care to address the point I raised originally?

Peter Skelton
.

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