The Wargamers' Special: Battle of Tukayyid 40,000

[Cpl Kendall]

That's not all I have to post, I'm doing this stuff in the mornings, so it will probably take a few days.

[Thanatos]

Give Kendall a boost here, unfortunatly the file with all my quotes is gone and so I need to transcribe them or get them from the original transcribers. Here's a couple though

In response to the claim that SM bolt pistols could only be used up to 100m

Muzzle flashes sparkled in the darkness as the traitors opened fire, but half a kilometre away their opening shots went wide of the mark. Boreas threw himself forward, covering the ground in five metre strides, preferring to close the range rather than fire. To his left, Thumiel paused and fired several rounds from his bolter, and Damas added his covering fire as well. Fifty metres on, Boreas skidded to a halt and leveled his bolt pistol as Zaul and Nestor advanced to his right. Thumbing the fire selector to semi-automatic, he [Boreas] emptied the magazine in five short bursts, the explosive bolts tearing through a knot of enemy three hundred meters in front of him."

Covering fire at 350m-400m and direct engagement at 300m.

I don't know how you're supposed to figure out the range for anything except the 300 meter stuff there. And even then the people shooting seem rather happy about scoring a hit with one shot on human sized (I'm presuming) target.

The protagonist is an utter boot who managed to have his first shots go wild at point blank range later. Skilled troops are capable of firing at much longer ranges.

Fencer got up to the nest top and raised his lasgun. Five hundred metres ahead, through the smoke and the rubble, he saw the first shapes of the enemy, troopers in heavy, ochre-coloured battledress, advancing in steady ranks.

Fencer began firing. Below Kolea opened up too.

And firing against vehicles and area targets happens from much farther.

The Hass [river] was almost three kilometres wide, icy cold and plagued with strong currents.
...
Folik, steering his ferry on a return run across the Hass, saw lights and movement on the north shore to the east. Zoican motorised brigades were sweeping in along the far shore from the pipelines and the Hiraldi road, pincering round to deny the escape route. The Zoicans clearly intended no one should survive the destruction of the hive. By dawn, the Zoican army groups were assaulting the tide of refugees on the north bank.
...
Now there was no way across. The ferries returned to the south docks, ,many under fire from Zoican forces on the north side, and tied up.
...
The Zoicans began to fire across the river into the tightly packed refugees. Despite the wholesale killing, it was a matter of hours before the civilian masses began to draw back into the hive.
..
Sporadic enemy fire from across the Hass stippled the waters around them and smacked off the hull. Parts of the docks were ablaze now. Folik expected a rocket or mortar to blow them out of the water at any moment. He fetched another bottle from the wheelhouse and a las-round punched straight through the cabin window and out the other side over his shoulder as he stopped to reach into the steerage locker.

The Zoicans are not elite troops for the most part. There are other examples of long range small arms fire but I need to recollect them. Of course, hitting targets at 3km with modern ARs is flat out impossible, so no big loss.

I'll go back four centuries for a good example, since now we expect professional soldiers to be trained marksmen using accurate weapons

Going back 400 years is a damn red herring. Its still hard to hit a running man sized target with an AR at 500 yards. Hell, depending on what weapon you use, it can be extremely difficult to hit a stationary target at 500 yards. Its basically luck to hit a target at that range with an AK-47 for example. However, at 300m you can easily put rounds into whatever you aim at.

Against a human (or Ork) wave, you need to wait until they're at a distance where missing is almost impossible but the enemy still has a lot of ground to cover before they get to you and a lot of ground to cover if they retreat. You actually wait until much closer IRL.

It is not because lasguns are inaccurate, its because a shooters fire will be more accurate at that range and therefore you can put far more killing power into your attack. It also saves ammo, which is vital when you face several thousand Orks each full scale attack and you're on the receiving end of those attacks five times a day.

Its clear that they could have fired earlier but chose not to in the original text.

"Eight hundred meters" Vidmir said, sighting in with the targeter clipped to the side of his lasgun, his calm voice barely audible above the sound of approaching thunder as the greenskins charged ever closer. "Keep yourselves cold and sharp. No firing until they enter the kill zone."

Furthermore, engagement distance is dependent on a number of variables, as we can see in this quote from Rebel Winter in regards to firing at Orks:

Maintain fire discipline. Power settings at maximum. Choose your targets. I want redundancy minimized. Remember, all of you, that temperature, visibility, and the nature of our opponent have reduced lethal range to approximately one-half. Any trooper wasting bolts on long shots will immediately forfeit his rahzvod allocation. You don't fire until I bloody well say so."

Also in regards to this post.

If you say Ogryn can drag APCs around, I expect it to have actually happened.

We see that this earlier post

We're talking about a battlefield where ogres with clubs get to engage APCs and tanks.

Was made in complete error.

The event in question:

Colonel Greiss tried to flex his hands. Nothing. He tried to raise his head but as he did so his vision swirled and he lost consciousness. He came round moments later, or minutes, or was it hours, it was hard to tell. His ears were booming from the noise of the explosion. All he could hear was a sound like something large and heavy being slowly dragged over an unyielding surface. His sight seemed to be growing dim and shadowy. Then he realised Nork was standing over him and beside Nork was the wreckage of the Chimera. The Ogryn had dragged the armoured carrier out of the ditch and twenty yards down the road.

"I said fetch the medi-kit, not the carrier, Nork," whispered Greiss. He was regaining the feeling in his arms and legs and didn't like it much.
"Da medi-kit is in da carrier, surr," beamed the Ogryn.

"Good thinking Nork," grunted the colonel through clenched teeth and mounting pain. "Now bring the medi-kit over here."

"Yus, surr!" came the loud and snappy response as Nork plunged into the Chimera, remembered he had forgotten to salute, came back, saluted twice for good measure, and busied himself searching for the vehicle's medical supply chest.

So basically, you took someones summation (Ogryn are strong enough to drag vehicles and could therefore be used against light vehicles) and so and ran in the opposite direction: That Ogryn routinely engage vehicles.

That's not the case

The ogryns were huge mutants, one of the few altered humans allowed in Imperial forces. Imposing figures, they dwarfed the Space Marines, standing a full head higher than even Haegr. Ragnar had heard stories of ogryns strong enough to lift tanks.
The massive creatures were pure muscle and stupid as rocks, with no mind except for killing. Unfortunately, that meant that their brains took longer to realise when they were wounded or even dead. Ragnar had once seen an ogryn fighting with a large hole in his chest, until a medic had pointed the wound out to him and he fell over.
The ogryns wore a mishmash of armour and were armed with ripper guns. The solid weapons had such a kick that only the large mutants could keep them steady, but they unleashed a massive barrage of fire, so much so, that each ogryn wore belts of ammo around their arms and chests. Moreover, each gun was at least as deadly as a club in hand-to-hand combat.

Ogryns primary method of combat is unleashing barrages of fire into infantry targets and then getting into HTH if necessary. IOW, they're shock troops.

A bigger issue here is that as the thread starter, you thought you would choose a force you thought useless for the scenario ("and the Ogryns are going to get butchered") which says something about you doesn't it?

I might be back later, I need to recompile my sources.[/i]

[Jedi Master Spock]

Give Kendall a boost here, unfortunatly the file with all my quotes is gone and so I need to transcribe them or get them from the original transcribers. Here's a couple though

In response to the claim that SM bolt pistols could only be used up to 100m

Muzzle flashes sparkled in the darkness as the traitors opened fire, but half a kilometre away their opening shots went wide of the mark. Boreas threw himself forward, covering the ground in five metre strides, preferring to close the range rather than fire. To his left, Thumiel paused and fired several rounds from his bolter, and Damas added his covering fire as well. Fifty metres on, Boreas skidded to a halt and leveled his bolt pistol as Zaul and Nestor advanced to his right. Thumbing the fire selector to semi-automatic, he [Boreas] emptied the magazine in five short bursts, the explosive bolts tearing through a knot of enemy three hundred meters in front of him."

Spraying a clump of enemies at 300m. Very impressive accuracy to hit 300m for something that's basically an oversized pistol, even if it is a clump of enemies; however, we can also note that the "traitors" in question (these are traitor Angel Space Marines, right?) were missing the three loyal Space Marines mentioned at 500m with their guns.

Two other elements of this quote are worth noting. First, the five meter strides. This has bearing on calculating the sprint speed and leg strength of Space Marines.

The second is that Boreas strongly prefers to close the range to three hundred meters and then stop before spraying a full clip of bullets (20-30 explosive shells, if this article gives correct ammunition capacity per clip) at the knot of enemy SMs. It's not quite dropping one shot on one Gretchin at 300m, but then, nor is it engaging at 120m.

The protagonist is an utter boot who managed to have his first shots go wild at point blank range later. Skilled troops are capable of firing at much longer ranges.

Makes perfect sense. He doesn't really know what someone who knows how to use the weapon well can manage.

Fencer got up to the nest top and raised his lasgun. Five hundred metres ahead, through the smoke and the rubble, he saw the first shapes of the enemy, troopers in heavy, ochre-coloured battledress, advancing in steady ranks.

Fencer began firing. Below Kolea opened up too.

"Ranks" of advancing enemies, five hundred meters.

And firing against vehicles and area targets happens from much farther.

The Hass [river] was almost three kilometres wide, icy cold and plagued with strong currents.
...
Folik, steering his ferry on a return run across the Hass, saw lights and movement on the north shore to the east. Zoican motorised brigades were sweeping in along the far shore from the pipelines and the Hiraldi road, pincering round to deny the escape route. The Zoicans clearly intended no one should survive the destruction of the hive. By dawn, the Zoican army groups were assaulting the tide of refugees on the north bank.
...
Now there was no way across. The ferries returned to the south docks, ,many under fire from Zoican forces on the north side, and tied up.
...
The Zoicans began to fire across the river into the tightly packed refugees. Despite the wholesale killing, it was a matter of hours before the civilian masses began to draw back into the hive.
..
Sporadic enemy fire from across the Hass stippled the waters around them and smacked off the hull. Parts of the docks were ablaze now. Folik expected a rocket or mortar to blow them out of the water at any moment. He fetched another bottle from the wheelhouse and a las-round punched straight through the cabin window and out the other side over his shoulder as he stopped to reach into the steerage locker.

The Zoicans are not elite troops for the most part. There are other examples of long range small arms fire but I need to recollect them. Of course, hitting targets at 3km with modern ARs is flat out impossible, so no big loss.

It's theoretically possible, mind, just not very likely. Packed refugees are a very large target to hit in any event. Lasers do have one very nice advantage in long ranged fire over ballistic weapons: No beam drop.

Going back 400 years is a damn red herring. Its still hard to hit a running man sized target with an AR at 500 yards. Hell, depending on what weapon you use, it can be extremely difficult to hit a stationary target at 500 yards. Its basically luck to hit a target at that range with an AK-47 for example. However, at 300m you can easily put rounds into whatever you aim at.

Against a human (or Ork) wave, you need to wait until they're at a distance where missing is almost impossible but the enemy still has a lot of ground to cover before they get to you and a lot of ground to cover if they retreat. You actually wait until much closer IRL.

It is not because lasguns are inaccurate, its because a shooters fire will be more accurate at that range and therefore you can put far more killing power into your attack. It also saves ammo, which is vital when you face several thousand Orks each full scale attack and you're on the receiving end of those attacks five times a day.

Its clear that they could have fired earlier but chose not to in the original text.

"Eight hundred meters" Vidmir said, sighting in with the targeter clipped to the side of his lasgun, his calm voice barely audible above the sound of approaching thunder as the greenskins charged ever closer. "Keep yourselves cold and sharp. No firing until they enter the kill zone."

This is about the best example so far for long range combat. The Guard are being told to hold their fire at 800m; that does imply that at least some of them think they can hit at that range. It is again a packed mass of enemy troops. If the Orks, who are not particularly disciplined AFAIK, not even trying to fire yet, though, that does support the contention that Orks generally prefer closer ranges for combat.

Furthermore, engagement distance is dependent on a number of variables, as we can see in this quote from Rebel Winter in regards to firing at Orks:

Maintain fire discipline. Power settings at maximum. Choose your targets. I want redundancy minimized. Remember, all of you, that temperature, visibility, and the nature of our opponent have reduced lethal range to approximately one-half. Any trooper wasting bolts on long shots will immediately forfeit his rahzvod allocation. You don't fire until I bloody well say so."

What are those conditions? Snowy mist?

So basically, you took someones summation (Ogryn are strong enough to drag vehicles and could therefore be used against light vehicles) and so and ran in the opposite direction: That Ogryn routinely engage vehicles.

I stand corrected. However, I will hold by that they seem to largely be close-combat soldiers in the Guard.

That's not the case

The ogryns were huge mutants, one of the few altered humans allowed in Imperial forces. Imposing figures, they dwarfed the Space Marines, standing a full head higher than even Haegr. Ragnar had heard stories of ogryns strong enough to lift tanks.
The massive creatures were pure muscle and stupid as rocks, with no mind except for killing. Unfortunately, that meant that their brains took longer to realise when they were wounded or even dead. Ragnar had once seen an ogryn fighting with a large hole in his chest, until a medic had pointed the wound out to him and he fell over.
The ogryns wore a mishmash of armour and were armed with ripper guns. The solid weapons had such a kick that only the large mutants could keep them steady, but they unleashed a massive barrage of fire, so much so, that each ogryn wore belts of ammo around their arms and chests. Moreover, each gun was at least as deadly as a club in hand-to-hand combat.

Ogryns primary method of combat is unleashing barrages of fire into infantry targets and then getting into HTH if necessary. IOW, they're shock troops.

A bigger issue here is that as the thread starter, you thought you would choose a force you thought useless for the scenario ("and the Ogryns are going to get butchered") which says something about you doesn't it?

I might be back later, I need to recompile my sources.[/i]

I tried to pick as wide a variety of Imperium armies as possible. Some are poorly suited to engage mobile enemies with long-ranged weapons.

I prefer to pick my arguments carefully. I felt that convincing Gniops that the Ogryn would do well against mobile heavily armed mechs was not worthwhile (or accurate) and so agreed with him promptly. The Sororitas I preferred to question a little more before giving their victory up for a lost cause, and I needed to run numbers on the Titans to see how the void shields ought to stand up to BT firepower.

I would still like to get a much better quantification of void shield strength, but it seems clear that they will stand up well enough to give Titans a very substantial advantage against BattleMechs.

[Cpl Kendall]

The second is that Boreas strongly prefers to close the range to three hundred meters and then stop before spraying a full clip of bullets (20-30 explosive shells, if this article gives correct ammunition capacity per clip) at the knot of enemy SMs. It's not quite dropping one shot on one Gretchin at 300m, but then, nor is it engaging at 120m.

I'm not sure if your doing this on purpose or not but you are ignoring the very nature, purpose and training in regards to why SM's fight as they do: They are shock/terror troops. Their entire purpose is to destroy the enemy in as gruesome a fashion as they can, to sow fear in the enemy.

This is about the best example so far for long range combat. The Guard are being told to hold their fire at 800m; that does imply that at least some of them think they can hit at that range. It is again a packed mass of enemy troops. If the Orks, who are not particularly disciplined AFAIK, not even trying to fire yet, though, that does support the contention that Orks generally prefer closer ranges for combat.

That's mainly because the Orkz were designed that way in the first place and tend to be terrible shots. Hence why they send out a Gretchin to be a sniper.

I stand corrected. However, I will hold by that they seem to largely be close-combat soldiers in the Guard.

That was never really in dispute, Ogryn are to dumb to serve anyother role and the Ripper Gun is a large shotgun.

I prefer to pick my arguments carefully. I felt that convincing Gniops that the Ogryn would do well against mobile heavily armed mechs was not worthwhile (or accurate) and so agreed with him promptly. The Sororitas I preferred to question a little more before giving their victory up for a lost cause, and I needed to run numbers on the Titans to see how the void shields ought to stand up to BT firepower.

I would still like to get a much better quantification of void shield strength, but it seems clear that they will stand up well enough to give Titans a very substantial advantage against BattleMechs.

There might be something in the HH series and Dark Adeptus, I'll add it to the list.

[Jedi Master Spock]

I'm not sure if your doing this on purpose or not but you are ignoring the very nature, purpose and training in regards to why SM's fight as they do: They are shock/terror troops. Their entire purpose is to destroy the enemy in as gruesome a fashion as they can, to sow fear in the enemy.

I assure you, it's not intentional. As far as I knew, SMs were simply the top elite forces of the Imperium's war machine. They have their own ships, supporting armor, and fight in major battles (i.e., Armageddon). I'm also aware there are a lot more Imperial Guards than Space Marines, but that Space Marines get more attention, both in games and in VS debates, and individual Space Marine units usually see action more often.

Even now, I have trouble getting around the idea that SMs might sow fear in the eternal Necrons, gung-ho Orkz, ravenous Tyranids, or Chaos Marines (who are every bit as brutal). That leaves regular humans and abhumans who are for whatever reason heretical or rebellious, Eldar, and Tau, right?

In this particular scenario, we are looking at Space Marines (and still debating how well they would do), and it is pretty important that we consider the ranges they would engage at, not just what range they could engage at. I think that the argument that the Space Marines outrange the BT units and would be shooting down mechs from out of their range falls flat for that reason.

I think the argument that the Imperial Guard units would do so passes that point - the Guard don't prefer close combat in the same way the Marines do - but it fails on account of insufficient evidence. The only argument I've seen so far that would suggest the Imperial Guard could outrange the Com Guard is to compare one set of BT mechanics with the fluff of WH40K; comparing to the BT novels, or the other sets of BT rules (air, space, and RPG scales) doesn't get very far in establishing a difference in effective range.

The third and final step, once we get past would and could, is to establish how much of an impact it actually makes in context.

For example, if Space Marines are completely ineffective at ranges of more than 300m, their range disadvantage doesn't matter as much if they combat-drop straight into the city. There, they usually don't have clear firing lines to or from them longer than 300m, and they're rarely more than a quick sprint from some kind of cover.

On the other hand, if they were out in a swamp, visible from a mile away, and slowly wading through knee-deep mud and water, it would matter a lot.

[Jedi Master Spock]

I found an interesting reference regarding the Land Raider fluff online, but I'd like to see if any of the WH40K buffs here can clarify it for me. The most complete statement of this claim is on Lexicanum:

• Armour: 91-95mm
  • Armour construction: 2 layers of Ceremite, 1 titanum/plasteel layer, 1 adamantium layer and 1 thermoplas layer, equivilent to 365mm conventional steel armour

The discussion section of the article points to Chapter Approved for the armor specifications, although one of the people citing the 365mm equivalence on a WH40K forum cite an older unnamed Imperial Armour book, and one of the discussions of a similar Thunderhawk armor equivalence points a finger at the Imperial Armor Update.

I doubt I'll be able to rifle through those this week. Maybe the week after next, but I wasn't planning on going through a giant crawl of older WH40K sourcebooks, and I'm not sure which ones to look at first. Can anybody else possibly confirm this and provide the actual quote - and more importantly, which precise Chapter Approved, Imperial Armour, or Imperial Armor Update volume these come from? There's more than one of each of those floating around, and I'm not even sure which of each I would want to start with.

This is close to the thickness of steel needed to stop a 5.2 megajoule bullet, so it's fairly consistent with what I've already outlined, but having more supporting data nailed down is always a good thing.

[Cpl Kendall]

To be clear, what exactly is it I should be looking for? The primary interest is Space Marine engagement range correct?

[Jedi Master Spock]

To be clear, what exactly is it I should be looking for? The primary interest is Space Marine engagement range correct?

Personally, I find a wide variety of incidents useful, and will use anything quantifiable to help build a coherent model. I find most interesting the things that can peg down weapons yields and resistance to weapons yields. Anything from recoil forces to waste heat and collateral damage can be useful for that.

However, I think ranges are the current primary interest for Thanatos and Gniops, who have made a significant claim that has little evidence presented in its favor so far:

Actually, we can determine that 40k ground forces engage at longer ranges by comparison of background for both sides.

Now, considering the volume of BT quotes posted, we have enough to throw out the idea that non-artillery BT weapons are ineffective a kilometer away. Clearly we can also throw out my earlier counter to Gniops' debunked 120m small laser claim; the Imperial Guard seems to think that opening fire well before 120m is a good idea.

We don't have enough information posted in this thread to say much about the effective combat range of lascannon, tank guns, and anti-tank missiles, which are the most important Guard weapons to consider in pitting the Guard against mech-based forces.

[Jedi Master Spock]

Well, I still haven't gotten a good look-through, but I do have a small batch of quotes relating to the Earthshaker artillery gun that came to my attention recently.

The ground whipped upwards, tossing her into the air as the first Basilisk shell impacted, blasting a crater fifteen meters across...

Using its standard 5 powder charges, the Earthshaker can reach out to approximately 16 km with a 38 kg shell.

The Earthshaker cannon is a 132mm calibre weapon, capable of firing a shell over 15 kms at a velocity of 814 mps.

These three points give loads of details on the Earthshaker cannon, usually deployed on a Chimera platform known as a Basilisk. The shell appears to have a bursting charge equivalent to 500 kg TNT, i.e., about 2 GJ explosive force. Earthshaker muzzle energy: 12.6 megajoules. Closest match RL weapon I'm aware of: 134mm British DP gun, vintage 1940, which fired 36.3 kg shells at 792 m/s. At a 45 degree elevation, range was 21 km for this weapon; a 16 km maximum range means the WH40K shells are not quite as aerodynamic, but is well within the realm of physical plausibility. A 16 km maximum range would be more typical of a 20-25 kg shell at that muzzle velocity.

If an average of 190 tons of force (1.7 MN) is applied to the shell during its flight through the barrel, this gives us a length of 7.4m over which the shell is accelerated. Given the comparison between Basilisk and tank models, this fits perfectly with the 190 ton recoil force mentioned earlier for a tank gun. We are talking about similar orders of magnitude for the operating pressures and low megajoule range muzzle energies for tank guns.

We do have a remarkable strength of high energy explosive in that particular novel description - 160 times the muzzle energy or so, equivalent to 13 times the shell's mass in TNT. This may prove to be an outlier, although it is well below the thermal energy of the particle projector cannon seen in Close Quarters, and also below the high end of lascannon yields.

What is that high end of lascannon yields? The highest suggested has been a couple gigajoules from any actual quoted incident - melting a 2.5 ton suit. For reference regarding partial to complete Space Marine vaporization, 7 gigajoules would be enough to heat and vaporize completely a Space Marine and his battlesuit if we assume the combination masses a full ton (and is mostly steel).

[Thanatos]

For reference regarding partial to complete Space Marine vaporization, 7 gigajoules would be enough to heat and vaporize completely a Space Marine and his battlesuit if we assume the combination masses a full ton (and is mostly steel).

*sighs*
They don't use steel. They use Adamantium and Ceramite among other things. Ceramite is a heavy duty thermal insulator, which means among other things its going to have a drastically lower thermal conductivity and higher specific heat. That's just the Ceramite. The other materials and the construction of the armor can also vastly effect its performance.

And can you actually show your work for once?

[Mike DiCenso]

Hold on, Thanatos, what evidence do you have from the rule books or the novels that Adamantium and Ceramite have physical properties that are signficantly better than steel or elemental iron? Do you have specifics that can be drawn apon? If so, how would the properties of the two materials result in substantial deviation from JMS' estimates?

By my very rough, back-of-the-envelope calculations, a soild 2.5 tonne block of iron would require about 19 GJ of energy to vaporize (2.5 tonnes * 1,000 = 2,500 kg. Multiply by 7.6 MJ gives you 19,000 MJ/ by 1000 = 19 GJ). Now obviously the suits aren't solid blocks of iron, and they do have a soft and squishy center in them, so most of that 2.5 metric tons will be distributated amongst calculating how much of the total mass is the Marine's body weight (made of water) and other substances. ;-)
-Mike

[Thanatos]

Hold on, Thanatos, what evidence do you have from the rule books or the novels that Adamantium and Ceramite have physical properties that are signficantly better than steel or elemental iron? Do you have specifics that can be drawn apon?

Some general ones

The armour is constructed using the same techniques as those used in the Land Raider. The armour is a layered composite of ablative ceramite layer, over a ceramite absorption and energy dissipation layer, over a thermoplas fibre mesh, over titanium rolled plates, over an adamantium inner hull. This provides superb protection from all incoming fire. The ceramite layers and thermoplas fibre mesh in the Thunderhawk are increased in depth to provide extra heat shielding during entry into a planet's atmosphere. The thunderhawk must be able to withstand repeated atmospheric entries, and as such the ceramite layers are thicker than a Land raider's. A useful side effect of this is that the hull of a Thunderhawk is also resistant to other heat based attacks, such as melta weapons or Eldar fusion guns. To compensate for the added ceramite the inner titanium and adamantium layers are thinned, to reduce weight.

One note about that: The titanium layer is a titanium plasteel alloy as described earlier on page 84. The thermoplas mesh is basically a heat transfer system designed to dissipate thermal effects.

As for Adamantium, in short:

At its front the familiar armoured beak common to most Imperial cruisers, many metres thick and composed of strengthened adamantium, the toughest material known to human science

Its used structurally, as a backing material for armor or as an armor material itself.

If so, how would the properties of the two materials result in substantial deviation from JMS' estimates?

Basically (and I'm really simplifying here), the energy required for melting and vaporization goes up dramatically since heat transfer is substantially decreased. It takes more energy per kg to raise it each degree.

[Mike DiCenso]

Hold on, Thanatos, what evidence do you have from the rule books or the novels that Adamantium and Ceramite have physical properties that are signficantly better than steel or elemental iron? Do you have specifics that can be drawn apon?

Some general ones

The armour is constructed using the same techniques as those used in the Land Raider. The armour is a layered composite of ablative ceramite layer, over a ceramite absorption and energy dissipation layer, over a thermoplas fibre mesh, over titanium rolled plates, over an adamantium inner hull. This provides superb protection from all incoming fire. The ceramite layers and thermoplas fibre mesh in the Thunderhawk are increased in depth to provide extra heat shielding during entry into a planet's atmosphere. The thunderhawk must be able to withstand repeated atmospheric entries, and as such the ceramite layers are thicker than a Land raider's. A useful side effect of this is that the hull of a Thunderhawk is also resistant to other heat based attacks, such as melta weapons or Eldar fusion guns. To compensate for the added ceramite the inner titanium and adamantium layers are thinned, to reduce weight.

One note about that: The titanium layer is a titanium plasteel alloy as described earlier on page 84. The thermoplas mesh is basically a heat transfer system designed to dissipate thermal effects.

First off, thank you for providing the quotes, Thanatos. I do appreciate the rapid response without any immature snide comments or attempts at ad hominem "smoke and mirrors" tactics.

Now, what you provide certainly gives us a look at some of the specifics of the suit's construction. We know now that just regular old rolled titanium plates is used here with an overlayed mesh and an outer layer of the ceramite. The problem is while we can work out the titanium vaporization energies pretty well, as it is a real-world material and it is very conventionally used here from a structural standpoint the other materials are again just outside of what we know. We can take guesses based on real-world ceramics and composites, but that is really just about all we can do. The description of the ability to withstand atmospheric entry at least gives us a a high melting point of up to 1,600 degrees c.

Interesting in that the titaninium and adamantium layers have to be thinned for weight reduction purposes. So out of out weight allowance of 2.5 metric tons, no one material, or the weight of the marine inside the suit can take up an overwhelming amount of the total mass here. So that helps us define the suit's properties better. Any cutaway diagrams of this suit's arangement? In all the WH40K books, I've seen and read, I don't recall anything like that, but for me it's been a long while, and I haven't kept up on things too much.

As for Adamantium, in short:

At its front the familiar armoured beak common to most Imperial cruisers, many metres thick and composed of strengthened adamantium, the toughest material known to human science

Its used structurally, as a backing material for armor or as an armor material itself.

Well that means it has good tensile strength and is probably highly resistant to brittle and cleavage fracture. But there's nothing to indicate that they are substantially built like the metre-thick armor on a space cruiser!

If so, how would the properties of the two materials result in substantial deviation from JMS' estimates?

Basically (and I'm really simplifying here), the energy required for melting and vaporization goes up dramatically since heat transfer is substantially decreased. It takes more energy per kg to raise it each degree.[/quote]

Uh, yes. But by how much is the question. For example, look at the following ceramics:

Barium titanate
Identifiers
CAS number: [12047-27-7]
Properties:
Molecular formula BaTiO3
Molar mass: 233.192 g/mol
Appearance: white crystals
Density: 6.02 g/cm3, solid
Melting point: 1625 °C

Solubility in water: insoluble

or conversely there are ceramics like Ferrite. Different densities, specific heat, and different applications. What we need to pin things down are the physical properties of ceramite. If ceramite is like a Space Shuttle orbiter thermal tile, or RCC panel it will have high specifc heat (up to around 1.200 C without ablating off), but will be relatively brittle and no good against the KE of an artillery shell impact.

So based on what I'am seeing so far, 19-20 GJ is still an extreme upper limit. I think this is actually starting to get somewhere.... Can you add anything else to help define the properties further?
-Mike

[Jedi Master Spock]

Before you go too far with your examples, I'd like to point out that the 2.5 ton figure is for a Tau Crisis suit, not a bog standard Space Marine suit. It's not without reason that I guessed the Space Marine + PBA suit combination at maybe a ton.

Tau Crisis suits are kinda big - you might look here - the big white guy and the big red guy are crisis suits, and the gold blobs are Space Marines. The little white guys are basic-grade Tau battlesuits.

For reference, the composite armor of a Land Raider is 91-95 mm according to the above. Assuming an eight foot Space Marine, total skin surface area is about 3.5m. Roughly, for every 28mm of total suit thickness, you have ~0.1 cubic meters of suit, and I would be amazed to find that Space Marine armor was much more than a third the thickness of Land Raider armor.

[Thanatos]

Now, what you provide certainly gives us a look at some of the specifics of the suit's construction

Actually, that's vehicle construction even though SM power armor is constructed along similar lines.

We know now that just regular old rolled titanium plates is used here with an overlayed mesh and an outer layer of the ceramite.

Titanium and plasteel alloy actually. Plasteel is a common vehicle armor material.

But there's nothing to indicate that they are substantially built like the metre-thick armor on a space cruiser!

I'm not saying it is, I'm using that quote because its flat out saying that its the strongest material known to human science in 40K.

I think this is actually starting to get somewhere.... Can you add anything else to help define the properties further?

Extremely thermally resistant but still good against projectile weapons.

In the book Traitors Hand, Jurgen hits a CSM center mass with sustained burst from a melta at close range and it only vaporizes the "middle of his chest". Meltas are multi GJ thermal weapons.