Grand 40K Quantification Thread

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Connor MacLeod
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Post by Connor MacLeod »

Imperial Overlord wrote: No, I mean exactly that. It will continue to accelerate as it leaves the muzzle of the gun so at close range its velocity will be higher. It will continue to accelerate past that but there will be factors like gravity, atmospheric density and so on acting on the bolt. So its velocity will probably be higher at close range (relevant for the example of a close range shot) than the muzzle velocity, even higher at mid range and decline at long range, depending on enviromental conditions. Unless you see an error in any of this.
Yes, my bad. I misread what you said. You're right, technically, the velocity would be higher after the bolt left the barrel. However, in this case, I doubt the range allows the impact velocity for the projectile to have increased very much beyond its muzzle velocity - with the woman virtually on top of him, he's got to be practically shoving that gun into her guts. I can't really begin to guess at the parameters involved (except that the KE would be transferred into the woman on impact, and the bolt would simply be accelerating her mass, and the resultant KE/velocity would be substantially lower.)

Note that in my original statement I was not assuming that the velocity came from the propulsion element - I was assuming the momentum came from the gun itself. As I noted, at that close a range, a thrust stream from the bolt would be..problematic at best (equal and opposite reaction and all that.. not healthy and certainly something difficult to fail to notice!) It becomes more plausible with the "grgavitic motors" Necronlord described (somewhat) but even then not much so. As I said, this weapon would be abnormally powerful from what I've seen/heard of from a bolt gun, and the effects described would imply some questionable abilities (multi km/multi-mile weapon ranges, substnatial destructive effects independent of the bolt's explosive element as well as overpenetration hazards, etc.) I don';t know how long bolter shells accelerate for, but even assuming a 2-3 second timeframe (an effective accel of around 200-300 gees), you'd need many kilometers or miles in which to allow the bolt to "accelerate up" to that velocity, and its trajectory would be extremely stable over that distance due to hits hypersonic velocity.

As I noted, at the very least this makes it an exceptional or unusual kind of b olt gun or boltgun ammo, rather than a standard one. (perhaps smething designed to take on Chaos entities of the large variety with.)
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Post by 18-Till-I-Die »

Here is some acceleration numbers from Sabbat Martyr i found...

Sabbat Martyr page 148--"Astropathicae report prameters verified. Perturbation reads at warp modulus eleven two nine seven, nine AUs out. Tracking cognents. Concordance estimated at ninety three minutes. Awaiting confirmation."

No, if i understand the Imperial naval talk, he's saying they detected a warp jump into the system nine AUs out-system, and it will take ninety three minutes to reach them from that point.

Now IIRC an AU is about 93 million miles, so that would mean these ships can travel that distance in ninety three minuets, or...roughly a million miles an hour?

Thats some prety rough 'math' i know but if i'm wrong maybe you cam make more use of it. My calc-fu is not strong. :(

I'm reading through some of the rest of the fleet battle, there might be more useful information.
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Post by 18-Till-I-Die »

Ugh! Edit: million miles a minute...i think.

I think thats right. Again i may be off with my attempt at calc-ing.
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Post by 18-Till-I-Die »

I was mistaken unfortunately, i misunderstood the terms they used it appears.

"Concordance" infers the arrival of a ship in real-space out of the warp. Not the time from the warp point to the planet. My mistake.
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Post by defanatic »

Connor MacLeod wrote:Is that a character literally commenting on the estimate of the ship? And what class of ship are we talking about? (potentail scaling cue, that)

I'm not sure what 700 meters "deep" means, I'm guessing height (vertical dimesnions rather than horizontal) but it could mean either.

This could be useful for deriving volume (and consequently, mass) estimates.
The ship is a freighter, I believe. For transporting cargo. Most Imperial battleships and stuff are larger.
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Post by GeneralTacticus »

And yes, that's a character directly commenting. Eisenhorn, IIRC (the books are told in the first person, from his POV, so anything in the narrative is seen through his perspective).
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Post by Connor MacLeod »

An AU in kilometers is about 149.6 million km.

9 AU is about 1.35 billion km, that works out to around 242,000 km/s.. (a little over .8c)

The acceleration works out to some 8000-9000 gravities, if my math is right. (this assumes straight-up acceleration with no slowing down. If they spend half the time, its probably closer to 17,000-18,000 gees.

What sortt of craft is this, incidentally?
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Post by Imperial Overlord »

Connor MacLeod wrote:
What sortt of craft is this, incidentally?
An Imperial squadron that is commanded by a battleship and includes both cruisers and grand frigates (apparently straddling the line between light cruiser and frigate).
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Post by Azazal »

Some IoM star ship info


From ANCIENT HISTORY in LET THE GALAXY BURN:
Story takes place on the Retribution. From the Battlefleet Gothic rule book, the Retribution is shown as a Luna class cruiser. The aremernt listed below matches the weapns loadout of Luna class in BFG. Also the story starts with the shipman's labour chant, Gothic Sector, Segmentum Obscurus. Same setting that BFG uses for historical engagements and plot info.

Page 332:
Kron told him there were forty guns with forty crews each, that sixteen hundred, another gundeck on the other side for three thousand two hundred. Then there were the lance turrets, port and starboard, nobody seemed to know just how big the crews for those beasts were, call it another sixteen hundred a piece.... That was six and a half thousand souls (give or take). The torps probably had a crew much bigger then a single gun, but less than whole deck - maybe a thousand. That made seven and a half... engines must be at least two or three thousand more...
Page 347:
Moments later an incandescent spearhead of het blossomed out of the cloud, dust and lightning rolled off it in plumes as the lens starkly announced it as enemy vessel [class: unknown]. 51,000 and closing
A few monents later the enemy ship fires at the Retribution and the shots hit in a matter of moments, no description of time is given, but it seems to be a few seconds.

Page 348, the Retribution fires back: T
he lights dimmed for a moment as capacitors charged and then the ship resounded with the clamour of the guns. Nathan felt the pressure of unseen forces hit him like a slap as forty guns hurled their payloads across the void. A moment later he saw the spearding projectiles cleaving towards the enemy. Np spreading storms of fire this time, the munitions detonated right beneath the enemy's prow.
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Post by Connor MacLeod »

Imperial Overlord wrote:
Connor MacLeod wrote:
What sortt of craft is this, incidentally?
An Imperial squadron that is commanded by a battleship and includes both cruisers and grand frigates (apparently straddling the line between light cruiser and frigate).
Were they all accelerating or just some of the ships (I recall vaguely mention of frigates, but I wasn't aware it included a battleship or cruisers moving either.)
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Post by Imperial Overlord »

Connor MacLeod wrote:
Imperial Overlord wrote:
Connor MacLeod wrote: Were they all accelerating or just some of the ships (I recall vaguely mention of frigates, but I wasn't aware it included a battleship or cruisers moving either.)
As I forgot to pick up my copy of Sabbat Martyr from my friend's house when gaming on Friday night I can't answer that question reliably at the moment.
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Post by Black Admiral »

Connor MacLeod wrote:Were they all accelerating or just some of the ships (I recall vaguely mention of frigates, but I wasn't aware it included a battleship or cruisers moving either.)
One frigate (the bulk of the fleet staying in Herodor orbit IIRC).
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Post by 18-Till-I-Die »

Black Admiral wrote:
Connor MacLeod wrote:Were they all accelerating or just some of the ships (I recall vaguely mention of frigates, but I wasn't aware it included a battleship or cruisers moving either.)
One frigate (the bulk of the fleet staying in Herodor orbit IIRC).
The frigate's fighter screen is described as being much faster, and outpacing it as they went. So the fighters, Lightnings, are considerably faster than that.
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Post by andrewgpaul »

Range and muzzle velocity info for the Earthshaker seige gun:
Imperial Armour vlume 3 - The Taros campaign wrote:The Earthshaker cannon is a 132mm calibre weapon, capable of firing a shell over 15kms at a velocity of 814mps
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Post by Connor MacLeod »

andrewgpaul wrote:Range and muzzle velocity info for the Earthshaker seige gun:
Imperial Armour vlume 3 - The Taros campaign wrote:The Earthshaker cannon is a 132mm calibre weapon, capable of firing a shell over 15kms at a velocity of 814mps
Well that's consistent with what I've mostly speculated on the guns. a 3 ton projectile at 814 m/s is around 2.5 million kg*m/s worth of momentum, and nearly 1 GJ worth of kinetic energy.
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Post by andrewgpaul »

Oh, and regarding the quote about the shell sending a Leman Russ skidding backwards,

Mass: 60T
Armour:
Turret 200mm
Superstructure 180mm
Hull 150mm
Gun Mantlet 100mm
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Post by Black Admiral »

The Leman Russ in question was the Conqueror variant, and explicitly stated in Honour Guard to mass 62 tons.
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Post by Lost Soal »

A bit on autocannons.

Nightbringer, pg 169
Heavy autocannon fire sprayed the roof of the building, churning up its pebbled surface and shredding human flesh. The men who had been waiting rescue in the flyers were the first to die, ripped apart in seconds by the heavy caliber, armour piercing shells. Vedden screamed as an autocannon clipped him, instantly shearing his leg from his body in mid thigh.
Anyone know how big a bullet needs to be to accomplish this?
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Power armour is capable of withstanding an unknown amount of autocannon fire. Although we know from Ghostmaker that it can penetrate.
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Post by Lost Soal »

Nightbringer, Pg 174
'So now the loyalty of an entire regiment of PDF troopers is in question?'
She swore. 'Thats nearly five thousand men'
Assuming this is standard throughuot the Imperium, then a PDF regiment numbers ~5,000 men.
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Post by white_rabbit »

Connor MacLeod wrote:
andrewgpaul wrote:Range and muzzle velocity info for the Earthshaker seige gun:
Imperial Armour vlume 3 - The Taros campaign wrote:The Earthshaker cannon is a 132mm calibre weapon, capable of firing a shell over 15kms at a velocity of 814mps
Well that's consistent with what I've mostly speculated on the guns. a 3 ton projectile at 814 m/s is around 2.5 million kg*m/s worth of momentum, and nearly 1 GJ worth of kinetic energy.
Unfortunately, Earthshakers really don't fire 3 ton shells :lol:
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Post by Lonestar »

andrewgpaul wrote:Range and muzzle velocity info for the Earthshaker seige gun:
Imperial Armour vlume 3 - The Taros campaign wrote:The Earthshaker cannon is a 132mm calibre weapon, capable of firing a shell over 15kms at a velocity of 814mps
What the Hell? That is much less impressive than modern artillery!
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Post by Dark Hellion »

Lonestar, the Basilisk is a light frontline mobile artillery. It is meant to be cheap dirty indirect fire that can still be meaningful on a battlefield where you may expect to see medium armoured vehicles or power armoured troops. They have the Bombard, which fires shells that can make a 125m+ crater in mud and has a range of at least twice that of the Basilisk, they have the Deathstrike, which can launch either Tac-nuke, Plasma, Viral, or Vortex warheads anywhere on a planet, or they can call in an orbital lance strike, melta-torpedoes, and when they absolutely have to end all life on the continent Bombardment cannon and Nova cannon.
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Post by Lost Soal »

The quote says over 15km. Normally you'd be forgiven for thinking thats just rounding down from 15.3 or something, but in this case its very meaningful. Give me a bit of time to pull the quotes together, and I think I can support ranges in excess of 50km.
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Post by The Grim Squeaker »

Lonestar wrote:
andrewgpaul wrote:Range and muzzle velocity info for the Earthshaker seige gun:
Imperial Armour vlume 3 - The Taros campaign wrote:The Earthshaker cannon is a 132mm calibre weapon, capable of firing a shell over 15kms at a velocity of 814mps
What the Hell? That is much less impressive than modern artillery!
How? What modern military artilley can fire 3 ton shells?
they have the Deathstrike, which can launch either Tac-nuke, Plasma, Viral, or Vortex warheads anywhere on a planet, or they can call in an orbital lance strike, melta-torpedoes, and when they absolutely have to end all life on the continent Bombardment cannon and Nova cannon.
They can also use Something (I can't remember it's name) else for bombardment, basically something made by divinely inspired Adeptus Mechanicus thats much larger than even a Titan- Some sort of gargantuan artillery , with each being unique.
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Post by Imperial Overlord »

DEATH wrote: They can also use Something (I can't remember it's name) else for bombardment, basically something made by divinely inspired Adeptus Mechanicus thats much larger than even a Titan- Some sort of gargantuan artillery , with each being unique.
Ordinatus is what they are called.
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