Fangz posted:

Sooorta in between. Consider this picture, which resulted from when a piece of aluminium is struck by a high velocity aluminium ball (depicted). The impact was slow enough that there's no *visible* spalling flying out the other side. But it's clear that *something* has happened.

quote:

For your edification - here is a (reasonaby) precise explanation of why
the spalling effect occurs.

A characteristic of shock waves produced by high explosive detonation is
that the pressure behind the shock front is not constant but drops off
very quickly (after all, the high pressure gases of the explosion expand
rapidly, causing the pressure to quickly drop back to atmospheric). This
zone where the pressure drops to (effectively) zero is called the "Taylor
wave" (see pressure diagram below):

pre:

          Taylor Wave
               |-----------| *
                           * *
                         *   *
                       *     * -> Shock front motion
                     *       *
                   *         *
                 *           *
      **********             **********

Another characteristic of strong shocks travelling through solids is that
roughly equal amounts of energy are deposited in a given (small) volume of
material in the form of kinetic energy, and in compression. This means
that as the shock front passes by, the material is accelerated forward to
some velocity V, and compressed at the same time. When it eventually
decompresses the energy released will add another velocity increment of
magnitude equal to V to the material.

When the shock front reaches the opposite side of the plate the pressure
suddenly drops to zero. The metal decompresses, and the compression energy
causes "velocity doubling", with the plate surface now travelling at 2V.

But, if the plate thickness is equal to the thickness of the Taylor wave
(several millimeters typically), then the outer surface of the plate has
already decompressed, but expanding in the opposite direction. Instead of
adding an increment of V, it subtracts V, bringing the plate velocity to
zero.

The zero pressure zones then travel into the plate from opposite sides,
one zone with a plate velocity of 2V, one with a velocity of zero. When
they meet, the tensile stress produced can exceed the strength of any
known material. The result - the 2V zone peels off and flys away (the
velocity of the spalling material can reach ~2 km/sec).

Any imperfections in the armor, and the method of fabrication will of
course affect the tensile fracture strength of the plate, but they are not
the cause of spalling. It will occur in any material with a plate of the
right thickness and a sufficiently strong high explosive shock.

Note that while this phenomenon is suppressed in very thin plates and very
thick plates, with sufficiently thin plates the detonation pressure alone
will shear the plate off and propell it inward, and sufficiently thick
ones cannot be used in practical tank armor.

PittTheElder posted:

Link? That 10,000,000 number sounds extremely dubious, if only because I cannot believe that a shaped penetrator is moving at orbital velocities.

JcDent posted:

Wait, so what aspects of lovely leadership got the Newfoundlanders killed, aside from "lets fight in WWI?"

quote:

General Hunter-Weston entered in a few minutes, and sitting opposite me said, ‘What an extraordinary thing war is!’ The progress of the day had greatly satisfied him, I could see, and he was in great glee. ‘Yes!’ I said. ‘But I wish to goodness it was all over!’ ‘My dear sir,’ he replied, ‘we’ll have years of it yet!’ I asked if he thought there was any possibility of its ending this year. ‘Absolutely none!’

quote:

"Many casualties?"
"Casualties? What do I care for casualties?

quote:

“I pray to God that the new leaders of these new formations may know how to get hold of their men and lead them, and yet on occasion drive them unceasingly without any regard to losses or fatigue, without any regard to the yelping of subordinate commanders for reinforcements or to their cry that their men are dead with fatigue. In the enterprise in which you are engaged push unrelenting, push without ceasing, push without mercy by a commander in whom the men have confidence is all important.”

quote:

"The 29th Div is down to small numbers now … These continual frontal attacks are terrible, and I fear the Generals will be called butchers by the troops. Hunter-Weston already has that name with the 29th."

quote:

"The planned attack allowed for twenty minutes to capture four lines of trenches, twenty minutes to consolidate and re-group, twenty minutes to take the village itself and a final ten minutes to capture the orchards and wood on the far edge of the village. 94th Brigade was tasked to take main responsibility for village itself. Brigadier-General Hubert Rees had only been appointed to command the brigade two weeks before the battle, and thus had little time to know the ground or his men, but he did know what could and could not be done. He argued fiercely, one of the few officers of any rank prepared to do so, with his corps commander that such a timetable was utterly impractical. Furthermore, as the northernmost brigade was next to the sector between Serre and Gommecourt that was not being attacked, the assault forces were even more than usually vulnerable to be fired at from their left, northern side, by German forces under no sort of bombardment or attack. Rees’s misfortune was that his corps commander, Hunter-Weston, known throughout the army officer corps as ‘Hunter-Bunter’, fits in every detail the common perception of the ignorant, stupid and stubborn general of the First World War; even his tall, upright stance and enormous moustache, fitted the picture."

"Hunter-Weston reluctantly allowed a compromise, an extra ten minutes, for the capture of the orchard at the extreme end of the brigade’s s objectives. Thus, in eighty minutes, by ten minutes to nine on the morning of the first day, Rees and his men were to overrun four lines of trenches, capture a fortified village 800 metres deep, and capture a wood and some orchards 300 metres beyond. No thought appears to have been given to the German menace from the left."

feedmegin posted:

Well - sort of. They learned quite a bit in the Spanish Civil War, both through sending the Condor Legion (a volunteer force recruited from the Luftwaffe) over there to fight and having observers on the ground.

(Not that participation in that necessarily helped prepare for World War 2 - the Italians sent a bunch of actual ground troops to Spain and still got creamed).

SeanBeansShako posted:

Started my mythical quest in attemping in selling my old Nan's seventies BBC TV British Empire magazines.

Day 1 so far, my local used books and main history book nerd of the region declined due to pretty much not taking anything now .

I really don't want to toss these things out.

Cyrano4747 posted:

Try ebay.

SeanBeansShako posted:

I had a peek earlier this week, deflated slightly seeing they sold brand new reprints (some company must have got the licence I guess) for live five pounds a magazine.

I mean, these are all first printed to subscriber runs from the early seventies. But they are slightly aged and not all of them are there. I mean, If I could I'd give them away for nothing as long as I knew they weren't pulped/tossed into a fire the moment my back is turned.

Sentimental value arrrrgh.

SeanBeansShako posted:

Might do that if e-Bay or the collectors I am contacting doesn't work out. I'm not asking for much really money wise. I need to make some room up now and since I have them all scanned I really have no need for them taking up a corner.

There is around eighty issues, some decent looking graphs, cartoons, old propaganda and photographs in them but this is BBC Enthusiast affair at the most so nothing too super special.

Cyrano4747 posted:

If things don't pan out PM me.

Trin Tragula posted:

The man was a complete oaf.

Trin Tragula posted:

See that strange square tower-y thing on the right? Hunter-Weston was obsessed with keeping fit and he liked to do calisthenics up there. The story goes that one morning in 1940, when he was 75, he went up there and opened the windows before starting his daily exercises, in the course of which he somehow managed to fall out of the window. It's not beyond the realm of possiblity that he might have jumped, although he left no note and I kind of like the idea that he was so incompetent he couldn't even exercise properly.

Nebakenezzer posted:

In my personal cannon that's exactly what happened.

Jobbo_Fett posted:

https://en.wikipedia.org/wiki/152_mm_howitzer-gun_M1937_(ML-20)

Weight of HE shell: 48.8kg

Muzzle velocity of HE shell: 600m/s


KE = 1/2 * Mass * Velocity, correct?

X = 0.5 * 48.8kg * 600m/s²

X = 0.5 * 48.8 * 360000

X = 24.4 * 360000

X = 8,784,000 joules

Unless I got my math wrong?


Edit: Keep in mind this is the energy as it leaves the barrel, not on impact

Jamwad Hilder posted:

It's probably something you picked up in general reading, assuming you've done a fair amount of research on the subject yourself already. I know that the Normans required 40 days of knight-service, and any days beyond that the lord would have the pay for their service. In addition to the 40 days of armed service, knights would also be required to spend a certain amount of time at their direct lord's castle, and depending on the barony you're talking about, royal castles may have been garrisoned by knights as well.

Another obligation of knight-service, which isn't directly related to the fighting days you're referring to, is that knights were basically obligated to pay a fee to maintain their status as knights as well. Being a knight meant taking on certain obligations, like the ones I outlined above. You have instances throughout the middle ages when a man-at-arms proves himself in battle but finds a way to (politely) decline being knighted. Some people think it's so they could avoid all those extra obligations.

Eej posted:

More than anything else, the idea of Knights having to remember to pay their Knight licensure fees every year is doing the most work in dispelling the mystique of knighthood for me.

feedmegin posted:

You shot him out of a gun? He might have been an oaf but going all Indian Mutiny on him seems a bit harsh

Nebakenezzer posted:

My personal cannon

Trin Tragula posted:

Nebakenezzer posted:

My personal cannon is not to be trifled with

Empress Theonora posted:

What happened to civilians who were stuck in enemy countries when WWI and WWII broke out? I just finished rereading Life After Life where in one of her lives Ursula gets stuck in Germany for WWII, and even though the reasons she couldn't leave were basically specific to the plot (jerk husband hiding passports, daughter getting sick at just the wrong time, etc.) it made me wonder how would somebody have gotten out? I'm wondering about WWI in particular, since the actual declaration of war must have seemed pretty summon to a public that had spent most of the summer reading about Madame Caillaux or whatever (It's a good thing the Ottoman Empire didn't enter the war immediately, or like half the cast of The Last Express would have had a very hard time getting home again).

Empress Theonora posted:

What happened to civilians who were stuck in enemy countries when WWI and WWII broke out?

feedmegin posted:

That and people are reluctant to believe the worst is going to happen right now until it does.

hogmartin posted:

Woo, no kidding. See also "Jews - Germany - late 1930s".

"What, just leave? Give up my business? My friends and neighbors? It couldn't possibly get that bad!"

hogmartin posted:

Woo, no kidding. See also "Jews - Germany - late 1930s".

"What, just leave? Give up my business? My friends and neighbors? It couldn't possibly get that bad!"

Cyrano4747 posted:

This is way, way over simplifying things. There were major barriers to emigration, not the least of which was the refusal of other countries to accept Jewish refugees. It also wasn't just "giving up the business" - emigres were required to forfeit virtually all of their belongings to the state. This hosed them over doubly: first off it is really goddamned hard to get established in a new country when you are penniless. Second a lot of the immigration regulations that were loving Jews already had extra-double gently caress you clauses if you were poor.

hogmartin posted:

I was intentionally over-simplifying how difficult emigration was, but there are tons of accounts from people who managed to do it and begged their families to come along. Lots of them didn't even try because how can we leave our home?

e: https://en.wikipedia.org/wiki/MS_St._Louis

Cyrano4747 posted:

edit: I suppose what I'm objecting to the most is the victim-blaming implicit in putting Jewish reluctance to believe that bad things were going to happen as a cause of all those deaths.

Empress Theonora posted:

What happened to civilians who were stuck in enemy countries when WWI and WWII broke out? I just finished rereading Life After Life where in one of her lives Ursula gets stuck in Germany for WWII, and even though the reasons she couldn't leave were basically specific to the plot (jerk husband hiding passports, daughter getting sick at just the wrong time, etc.) it made me wonder how would somebody have gotten out? I'm wondering about WWI in particular, since the actual declaration of war must have seemed pretty summon to a public that had spent most of the summer reading about Madame Caillaux or whatever (It's a good thing the Ottoman Empire didn't enter the war immediately, or like half the cast of The Last Express would have had a very hard time getting home again)

Trin Tragula posted:

chitoryu12 posted:

....and then he got obsessed with a young girl down in Key West, stole her body from her tomb, and rebuilt her decomposing corpse for 7 years until it looked like a giant wax doll before her sister finally caught on.

It's an interesting story.

Nebakenezzer posted:

awwwwwww

What is that? Dog-hauled Cannon? Concealed-carry cannon?

Nebakenezzer posted:

Dog-hauled Cannon?