Astartes: Impact damage?

[Dlatrex]

While playing the THQ SPACEMARINE, I remarked how dramatic an effect a jump-pack wearing marine could have on anyone unfortunately to be underneath him when he landed. Heck, unlike most jet-pack assisted combatants, it looks like the jets are used to *increase* his rate of descent for the purposes of kinetic attack. We don't know exactly how heavy a fully armored astartes is (at least that I'm aware of) but I'm sure someone could fudge it and come up with a comparable sized impact from artillery etc. Do we have any physics majors who offer to estimate the damage incurred by an assault marine's 'Hammer of Wrath'?

Tangential to that, is the fact that the marines even use the jump-packs at all, for arresting a fall. Are there examples in any of the novels which indicate a well equipped marine has been seriously injured or killed by a fall from a great height? I am wondering if they are supposed to be durable enough to survive a comparably sudden impact from terminal speed. Although Hollywood-ized they did show Captain Titus having no problem doing a front roll off of a falling Valkyrie :cool:

[Rev. Tiberius Jackhammer]

I hear that (due to a weird way fall damage works at very low character levels), starting characters in the Deathwatch RPG can easily die from falling down the stairs :P

[Kyban]

The thunder hammer tends to amply the effect as well. :D

[Dlatrex]

I hear that (due to a weird way fall damage works at very low character levels), starting characters in the Deathwatch RPG can easily die from falling down the stairs :P

That is awesome, and now I want to play Deathwatch.

[Cursed13]

Well, if we assume the Deathwatch rulebook is correct, then Power Armour is 180 kilograms, and a Jump Pack is 50 kilograms. Both of which sound reasonably correct, assuming the weight of ceramite, fibre bundles, wiring, fuel, and other components. Then for the Space Marine himself, we'll assume the average battle brother is another 180 kilograms. So all told, he would be about 410 kg on average, or a little over 900 pounds. So to tally that out for easier viewing:

Power Armour: 180 kg / 396 lbs
Jump Pack: 50 kg / 110 lbs
Space Marine: 180 kg / 396 lbs

For those who would bring it up, no I don't believe the weight of the Power Armour includes the weight of the marine wearing it, considering how heavy muscle mass is and the size of an Astartes, it would mean Power Armour is ridiculously light. So I am going to assume that the weight of Power Armour is just the Power Armour with no marine inside. Hopefully that helps shed some light on the situation.

As for Space Marines falling from the sky or out of Valkyries, if you take into account how presumably strong and durable the gene-forged body of a Space Marine is, as well as the reinforced muscle fibre bundles of power armour to support them, a Space Marine can reasonably fall a good distance without having to worry about kinetic damage. However, that isn't to say that a Space Marine won't suffer the effects of kinetic trauma from falling extremely high distances. Even from 20 feet up (or about six inches in 40K game terms) a Space Marine will still suffer some damage to his legs, however the suit will inject painkillers and the bones will start to mend immediately. More than 20 feet, I would assume that the fall damage will be enough to render a Space Marine either unconscious or dead, depending on from how much higher he falls.

With all that in mind, if about 10-15 feet is a safe fall distance for a Space Marine, imagine a 900 pound armoured object falling from 10-15 feet up, it would cause pretty significant damage to anyone who stands around long enough to get hit by that. A Strength 4 attack seems pretty reasonable representation.

[DarkLink]

As for Space Marines falling from the sky or out of Valkyries, if you take into account how presumably strong and durable the gene-forged body of a Space Marine is,

Actually, the bigger something is, the worse off it is against falls. Ants can fall from terminal velocity and walk away. Cats can escape pretty high falls relatively unscathed. Humans, not so much. And forget Elephants. This is because mass increases to the power of three, while bone and muscle strength is merely squared as you scale up a body. Having thicker bones only helps you so much when it adds more weight than it protects you from.

[Cursed13]

Ah DarkLink, you again, you sure do love to pick apart small things I say and make a big deal out of them without addressing the entirety of their context. But certainly you do bring up a good bit of information. Although you're still not entirely correct. It goes beyond much more than merely "thicker bones".

[Nabterayl]

The trouble with comparing the impact of a space marine to artillery is that a 900 pound object moving at a few 100 meters per second is not likely to cause much in the way of shock waves (more likely to just plow a hole into the ground). When an artillery shell explodes, it does create shockwaves. According to Deathwatch, a jump pack can get you a maximum altitude of 144 meters above your starting point in a single jump. A 410 kg space marine, falling from 144 meters, on a planet identical to Earth, will land in 5.4 seconds with a velocity of 53 m/s and 580 kilojoules. That's about as much energy as is released by a hand grenade, only a hand grenade's energy is directed at moving air and matter towards the target(s) and a falling space marine's energy is directed at the ground.

Not that kinetic energy transfer is a very good way to go about figuring out how badly somebody will be wounded by intersecting the path of a moving object, but that should give you some idea that while a space marine with a jump pack falling on you will be very bad for your health, that same space marine falling next to you will not do much. As for the effect of a space marine slamming his thunder hammer into the ground at the end of a fall ... probably not what THQ shows, but without having any way to quantify a thunder hammer's energy blast, not much fake physics can be done on that problem.

[DarkLink]

I'm just sayin'. Anyways, assuming a fall at a human's terminal velocity of approximately 200fps. I'll also use the weight of 900lbs. On impact, the Space Marine hits for 1.8*10^7 foot-lbs. That's 24.4 megajoules, which is equivalent to approximately six kilograms of TNT.

[Psychosplodge]

Apparently a cat has a non-fatal terminal velocity as long as it falls from above 6 floors, (I wonder if that's our six floors or your six floors?) but it needs that much distance to ensure it's feet down when it lands...

[Wildeybeast]

Evolution is also a factor. Cats legs are evolved to be springy because they had a habit of falling/jumping out of trees. They are also about the maximal size to be able to survive falls with little to no damage partly because of their weight, but also partly because they are small enough to right themselves and land on their springy legs before they hit the ground. Fat cats are far more likely to get injured because they are less likely to be to right themselves as they fall faster.

As for marines, does anyone know what sort of padding the armour has inside? It would need to have some significant shock absorption properties to stop a marine hitting the ground at speed from getting mushed. Though, again we are looking for science in a science fiction universe.

[Nabterayl]

We don't, but we also don't actually know that a marine does hit the ground at speeds greater than, say, a paratrooper. Sure, THQ loves to portray it that way, but that doesn't mean it's so. Hammer of Wrath doesn't prove that they hit the ground at very high speed either; Hammer of Wrath can clearly represent surprise as much as impact (e.g., GK interceptor squads still get Hammer of Wrath, even though they're just popping out of thin air next to you). If one were writing a 40K piece with a serious tone, I'd be inclined not to have jump pack marines colliding with enemies, or slamming into the ground at super high speeds.

[Dlatrex]

I think that the closest you'll find to a discussion of the interior of power-armor is the beaky picture from way back in the RT days:

http://wh40k.lexicanum.com/mediawiki/images/6/63/Mk6corvuscompositiom.JPG

Beyond the Black Carapace (which is more properly a cybernetic implant) I don't think there is much mention of what type of contact points the armor features for the wearer.


Cursed, thanks for crunching some numbers for us! I think you err on the cautious side, which is perfectly reasonable and a good way to approach something like this that is very non-specific with parameters.

Nab, the number you crunched all seem to work just fine. I didn’t realize that anyone had listed specs on the operation of the jetpacks! Looks like we’d be a slightly below terminal speed for a falling human, at 144 meters up. Could we also calculate the acceleration at liftoff? I’m wondering if (like in the video game) the energy will go up significantly if the marine fires up his jets on the way down. Mind you, this does not bode well for the astartes looking towards our discussion of their durability to fall damage.

DarkLink I tried to follow your numbers but came up short. Did you remove the acceleration for G? I get a figure closer to 760 kilojoules for those parameters.

So….are they surviving impact due to awesomely designed armor, padding, and joints, or is their physiology just THAT robust? I can’t find too many cases of gorillas sustaining massive trauma due to falls, but that may just be we don’t record them falling very frequently.

As to the discussion of the astartes physiology at large, it is only worth mentioning the work of Phil Sibberings. Although the information is conjecture on his part, I think he is realistic in his extrapolation from what we’ve seen in the background from GW. So if anyone has not seen his work yet, please enjoy!

http://www.philipsibbering.com/wh40k/images/10-01-p02_anatomy-750.jpg

http://www.philipsibbering.com/wh40k/10-01-marine-morphology.shtml

[Psychosplodge]

As for marines, does anyone know what sort of padding the armour has inside? It would need to have some significant shock absorption properties to stop a marine hitting the ground at speed from getting mushed. Though, again we are looking for science in a science fiction universe.

So really they could have some sort of inertial compensator so they don't actually feel the effects...

[Wildeybeast]

What do you mean by an inertial compensator? You could put shock absorbers on the knee joints to stop your legs going into your lower intestines, but you'd still shatter every bone below your knee. And if the armour lacks padding, it will do absolutely nothing to stop massive damage to internal organs from the impact. Put simply, humans have precisely no evolutionary adaptations to help with hitting the ground at speed. Being an abnormally large human in heavy suit of armour does not improve this situation.

[Kyban]

Inertial dampeners are a staple of most sci-fi, it wouldn't be unreasonable for them to put them in power armor.

[Psychosplodge]

I was thinking a field akin to what they use in ships in the likes of starwars and startrek to offset manoeuvring g at stupid velocities

[Nabterayl]

It's always possible, though I doubt it. You can put a marine out of action without penetrating his armor, and the only way to do that is through concussion. So if they do have some sort of magic inertial compensator technology, it can't be very good.

Remember also that a jump pack doesn't put out very much thrust. If we go by Deathwatch, a jump pack isn't good for more than about 2g's (less, depending on how you calculate it, because Deathwatch gives the velocity a jump pack can achieve, which is always constant no matter how long it's been on, which is ... not how physics works =P. I've chosen the least conservative number, which is still very small). If jump packs aren't putting out very high acceleration, and things like autocannon shells can injure a marine enough to take him out of the fight, they probably don't NEED very good acceleration compensation gear.

[DarkLink]

Does is specify velocity or acceleration? 2g's is an acceleration, so that would actually be a reasonable measure for the thrust of a jump pack. Otherwise, that's pretty funny. Writers are so cute when it comes to physics sometimes:). Like little kids with crayons.


What do you mean by an inertial compensator?

Intertial comphensator is sci-fi code for "magically ignores inertia", though it usually only does in such a way that allows space craft to maneuver quickly without killing the pilot, or in some similar specific matter. If someone really wanted to get science-y about it, I'm pretty sure something that allowed you to ignore inertia would make for some incredibly useful but much more mundane technologies.

If anyone here reads Schlock Mercenary, though, the powered armor in that webcomic does contain a form of inertial compensator, with a pretty reasonable explanation for how it works.

[Nabterayl]

My bad, I misread the jump pack rules. They specify a speed, but it's faster than what I first thought - up to 36m/5s, with a maximum continuous burn of 60 seconds (though no endurance limit, so presumably the 60 seconds is gated by something other than fuel). That's 16 mph, but the acceleration is unclear - 36 meters straight up in 5 seconds is very different from 432 meters (I got my earlier figure wrong, obviously) in 60 seconds.

Either way, Deathwatch clearly represents jump packs as fairly low velocity things. The actual thrust involved may be pretty big, since they have to move a fairly large mass, but the speeds involved are clearly not.

[Tynskel]

hmmm...
for some reason I think that's wrong. it may be in the books... but the book... are usually pretty bad, when it comes to numbers (the inquisition changes to the numbers to protect... the innocent?)

I would think the game "Space Marine" would be a better representation of how jump packs work. Short bursts with very high acceleration. Not to mention, their 'impact hits' are not necessarily directly hitting anyone, but the impact shockwaves do hit everyone. If a Space Marine can do that, and is not effected by the own shockwave (because it will travel through them too), then they probably 1) have shock dissipation armor, 2) body structure designed to absorb concussive blasts.


You would want short bursts of acceleration for a CC platform. You want to minimize the 'air time' that a unit has to prevent them from being blasted.

Tau battle suits are the opposite, they must have extremely variable acceleration in their suits. They also need long duration burns, because they need to maintain stability for firing solutions. Tau are very good of hopping in and out, which implies a incredibly complex acceleration system. Probably not as robust as a Space Marine Jump Pack, however, while kept to operational standard, provides an excellent stable firing platform.

[Nabterayl]

I dunno, I think Deathwatch hits the historical tenor of the lore on this one better than THQ. The only indication we have ever had that a marine lands with enough force to generate a shockwave is THQ, which is also the company that lets a single swing of a chainsword hit multiple guys, and marines slam thunder hammers into the ground so hard it can create shockwaves. There's no reason to believe a space marine can generate that much force. A tabletop jump infantry model can move twice as fast as a model advancing under combat conditions, by which metric 16 mph is, if anything, fast. 12" = 16 mph also fits in pretty well with the vehicle speeds we see on the tabletop.

[Tynskel]

I still think it closer to canon.

16 mph is sloooow. Not to mention, a marine moves just as fast as a guardsmen?
Using distance on the table top is a horrible abstraction. We all know that.

The thunderhammer shockwave is easily explainable because of the weapon's properties-even the gravity hammer for halo does that. Also, I have seen more rules from THQ enter the tabletop than I have from the books and RPGs. Even a full fledged Space Marine army got its own special rules in 4th Edition.

I am just hopeful that Dark Angels get a vengeance launcher. Assault 1 24" Str 5 AP2 Blast... here's to hoping...

[Nabterayl]

You don't want any air time for an assault unit, even one with jump jets. Juan Rico said so ;) That's how assault marines used to be, and that's how they should stay :p Give me my love children of Bretonnians, British commandos, and Mobile Infantry over your rocket-powered meteor-men any day.

But still ... you can take out a space marine with the explosion of a 25mm shell, but he hits the ground hard enough to create a shock wave that can kill people? That just doesn't gel for me.

[Tynskel]

That 25 mm shell is exploding inside the human body, after piercing the armor...

Juan Rico know's his stuff.
I am surprised Assault Marines do not get equipped with 30 second bombs.

[Nabterayl]

Autocannon shells penetrate power armor?

But seriously, Rico said it best. Assault marines have always been way less over the top than marauder suits. I can buy THQ influencing a new, higher-power marine aesthetic, but I stand by my statement that 16 mph is in the right ballpark. Too slow, sure. I can agree with that that. But by a factor of two or three, I think. Maybe four.

EDIT: Somewhat back on track, if an Astartes frag grenade contains 500 grams of TNT equivalent (about 2.5 times as much as a regular frag grenade), it has a chemical potential energy of 2.35 MJ. To equal that, a 410 kg marine would have to be moving at 107 m/s, or 240 mph, which is three times the maximum speed of an Astartes motorbike or slightly more than the top speed of a Land Speeder. This is about the speed he would achieve if he were falling from 600m, which is six times the service ceiling of a Land Speeder.

If he was moving that fast, the marine would be able to create as much of a shockwave as a hand grenade - except that all of his energy would be directed down into the earth rather than into the air, so the effect would be about as impressive as a shaped charge with no backblast being discharged into the ground - somewhat less destructive, say, than a krak grenade oriented to detonate downward, which I'm sure we can all appreciate would be very anticlimactic. The amount of speed a jump marine would need to create a meaningful shockwave is really, really big.

[DWest]

While I have nothing to positively back this up, here's a swing at a theoretically-plausable way to make Titus explode on impact . . . er, the way in which we want him to, as opposed to the way that makes the game end very quickly:
-the armor would need some kind of ideal foam lining sandwiched somewhere in the structure; the exterior plate "floats" on top of this foam. Using the Ideal Gas Law (well mugging it for quid with which to buy some psudeoscientific cred), we can basically say this: When the foam is compressed (by say an autocannon shell hitting the armor, or Titus landing on something at Ludicrous Speed), since the quantity of the gas remains constant, the compression of the foam causes an increase in temperature, thus converting mechanical energy to thermal energy, which can be consumed by the armor's powerplant.
-Since this is the 41st millennium and technology, when it works, works extremely well, the armor is presumed to have some method of reversing the process, and converting stored thermal energy back into mechanical energy, directed outward in a reversal of the initial event. When configured correctly, the armor can skip the conversion-to-thermal step entirely, and direct the force of impact outward rather than up through the body.
-As for why Titus exhibits this effect more prominently than other Space Marines we've seen thus far, well, Titus is working alone; exploding like a frag grenade every time you're shot doesn't do much good when you're standing amidst your Battle-Brothers (in fact, I'd imagine the Chaplain would probably give the offending Marine a corrective bludgeoning for being a heretic and scoring an "own-goal"), it does a lot of good when you're all alone and landing in the middle of twenty metric tons of Ork. Likewise, the effect isn't observed during ranged combat, as the suit is absorbing the energy to keep the battery topped off, and it likewise isn't seen in normal melee combat, because the energy of a single Choppa hit just isn't going to make a big difference when re-radiated in all directions.

[Psychosplodge]

It's always possible, though I doubt it. You can put a marine out of action without penetrating his armor, and the only way to do that is through concussion. So if they do have some sort of magic inertial compensator technology, it can't be very good.


Well I'd assume it's probably power hungry, and only activates during a fall. But if they have antigrav for land-speeders and suspensor tech to lighten heavy weapons it's not a huge jump.

[bfmusashi]

We can assume a lot of things because of all the robot magic running around. Don't bring smart things to 40k, it's a stupid place and it will punish you for it.

[Psychosplodge]

lol, but only if it supports your own argument...

[Tynskel]

yes, an autocannon can pierce power armor. Bolter shells are designed to pierce power armor.
An autocannon is a serious threat towards marines.

What people don't realize here is the difference between piercing armor and 'ignoring armor'. AP3/2/1 will always make a mockery of power armor. In almost every single case of AP3/2/1 the weapons are designed for destroying tanks: Missile, plasma, and melta weapons.

A marine that survives being hit by a AP3/2/1 is essentially lucky. Even then, they are probably out of commission, and need medical attention. You know, for their face melting, limbs being vaporized, or guts splattered every which way.

[bfmusashi]

lol, but only if it supports your own argument...

Touche!

[Psychosplodge]

Touche!

:D

[Nabterayl]

Bored at work = thread necromancy!

According to Starship Troopers, a Marauder suit doing a "fast" sweep is moving 40 mph. A Marauder suit is also way more capable than a jump marine, though, so I'm sticking with 16-20 mph being a reasonable speed for a jump pack.

410 kg is light for an assault marine (since it doesn't include the weight of weapons and equipment), but let's stick with it as a baseline. 410 kg moving at 20 mph (= 115.2 mps) is carrying 2.7 MJ of kinetic energy. A normal human has about 1.9 square meters of surface area. That means even if the marine's impact was spread over the entirety of an adult human male (and of course it's concentrated in an area somewhat less than half of that), the unfortunate victim would feel a pressure of about 1.4 MPa. Call the actual pressure something like 2.8 MPa, which is probably a bit low. For comparison, a .45 ACP round exerts a pressure of about 5.3 MPa - and, I presume, exceeds the pressure required to penetrate a human body by more than twice. Now of course as we all know from car collisions, the wildly different momentums will mean that the marine will knock its target flying while a bullet will just go right through. But you get the idea. Alternatively, a car moving at about 5 mph carries about 0.50 MJ of kinetic energy, and that's about the speed threshold to injure a human body. Being six times over that threshold won't automatically kill you. But it will be very bad for your health, especially if in the next few seconds you're expected to fight the thing that hit you at six times over the threshold to injure you from collision alone. Assuming he didn't land on you, in which case, yeah, you're dead.

So shockwave damage, negligible. Collision damage, while not automatically fatal, very much not negligible.

[Psychosplodge]

Doesn't a skydiver land at approx 30mph?

Cause I'm sure when they had that Lad's army on the tv they started parachute training by jumping out the back of a lorry at 30mph

[Tynskel]

I still stand by the fact that Assault marine move much faster than 20 mph. You are not going anywhere at 20 mph. Another thing to think about is that the tanks move much faster than 20mph, too, and an assault marine, on the short term, is much faster than tanks.

THQ has it right.

One simply cannot use the numbers in both Deathwatch and on the tabletop. Why? Because the mechanics are designed towards balance.
I would venture to state that an assault marine is faster than a Starship Trooper, but a Starship Trooper has the advantages of many many many times more firepower. (it has nukes!)


There are some other problems with the mathematical analysis. 1) Impulse is not discussed. 2) momentum changes should be described more. A shockwave in not completely dependent on the energy involved in the collision, but is also related to the momentum change.

Take a bazooka. The round has no explosive. The projectile hits a target and bounces off. That is a 2x change in momentum (remember momentum is a vector). The 2x change in momentum is imparted to the target, as wave. This wave then interacts with a free surface (a surface where the density change is an order of magnitude different) reflecting off that surface. That, again, is 2x momentum change in the wave. Spallation is actually what destroys the target. Pieces of the target flake off with up to 4x momentum change from the original bazooka projectile.

[Psychosplodge]

Isn't starship trooper "power armour" more akin to a tau battlesuit?

[Tynskel]

Yeah, and I would say even more sophisticated.
They are dropped from orbit, and carry many more weapons.

[Rev. Tiberius Jackhammer]

I'd figure that although an Assault Marine can move as fast/faster than a Marauder, the Marauder's much more agile/can accurately attack while moving/make course corrections, right? Meanwhile, an Assault Marine's movement seems to be more like a self-propelled mortar :P

[Nabterayl]

I still stand by the fact that Assault marine move much faster than 20 mph. You are not going anywhere at 20 mph. Another thing to think about is that the tanks move much faster than 20mph, too, and an assault marine, on the short term, is much faster than tanks.
Not much faster. A Leman Russ's maximum speed is 22 mph, even less off-road. A Predator, which is only sort of a tank, can pull 42.5 mph on a road, 31 mph with the pedal to the metal off-road.


I would venture to state that an assault marine is faster than a Starship Trooper, but a Starship Trooper has the advantages of many many many times more firepower. (it has nukes!)
Maybe in the short term - I'm not denying it's possible. But I don't see what evidence you have for that besides THQ's depiction and your idea of how fast an "assault" trooper ought to be moving.


There are some other problems with the mathematical analysis. 1) Impulse is not discussed. 2) momentum changes should be described more. A shockwave in not completely dependent on the energy involved in the collision, but is also related to the momentum change.

Take a bazooka. The round has no explosive. The projectile hits a target and bounces off. That is a 2x change in momentum (remember momentum is a vector). The 2x change in momentum is imparted to the target, as wave. This wave then interacts with a free surface (a surface where the density change is an order of magnitude different) reflecting off that surface. That, again, is 2x momentum change in the wave. Spallation is actually what destroys the target. Pieces of the target flake off with up to 4x momentum change from the original bazooka projectile.
I'm ... not sure what you're talking about. Even the original bazooka fired a rocket carrying 1.6 lbs. of high explosive (http://www.designation-systems.net/dusrm/app4/m6rocket.html). Are you talking about the effect of a dummy bazooka projectile on a target? The effect of that will be negligible, unless you're talking about shooting a dummy projectile into a person, in which case the target is certainly likely to be injured by a rocket crushing his tissue at 180 mph.

I'm aware of the momentum changes involved, which is why an assault marine wouldn't simply blow right through somebody. The collision will be less severe than a car hitting a pedestrian at a given speed, since the car weighs 2-3 times as much as an assault marine but can be moving just as fast. Momentum conservation is why an assault marine will cause a person to go flying, rather than go through him.

Continuing the car analogy, imagine you're standing with your back to a concrete wall when a car slams into it at 100 mph, missing you by inches. You have to worry about fragments of car, and fragments of wall, slicing into you. But you do not have to worry about the shockwave. Despite carrying (I think we all agree) far more momentum and energy than an assault marine, the car hitting the wall will not force air into your bodily cavities with sufficient force to rupture them, which is how a shockwave wounds somebody.

[Psychosplodge]

Not much faster. A Leman Russ's maximum speed is 22 mph, even less off-road. A Predator, which is only sort of a tank, can pull 42.5 mph on a road, 31 mph with the pedal to the metal off-road.

That's poor, A challenger two will do 35/25mph on/off road, and that's the official figure, I've heard people say in reality they are capable of going faster.

A predator being based on an APC platform rather than a tank platform would be more like the Scorpion
and have a more realistic 60mph ish speed.

[Nabterayl]

It's poor because it's meant to be poor. Like many not-hard-sci-fi universes, 40K surpasses modern technology in some ways but falls far short of it in others. We've had debates before about how good 40K armor is, so it's possible that Imperial armor and weapons are better than modern day, but there's no denying that any modern MBT would kick the *** of an "equivalent" Imperial vehicle in terms of things like speed, crew comfort, accuracy on the move, stealth, and so forth.

EDIT: that is to say, it's SUPPOSED to be sub-modern. 40K is not so much space warfare as it is "What if Montgomery had had jet packs?" It's closer to steampunk in that sense (skullpunk?). While it is silly that technology tops out at about the 1940s, internally it hangs together. The indisputably sci-fi elements, like spaceships, are always depicted as incredibly rare, and the common tech is unbelievably primitive in its capabilities. If it were otherwise, units like the Mordian Iron Guard would be combat ineffective.

[Dlatrex]

I still stand by the fact that Assault marine move much faster than 20 mph. You are not going anywhere at 20 mph. Another thing to think about is that the tanks move much faster than 20mph, too, and an assault marine, on the short term, is much faster than tanks.

THQ has it right.


Hmmm...since this did start as a "THQ question" the presentation in game does warrant looking at in greater detail. I'll try to take more accurate measurements at home, but just from eyeballing some video's of the assault marine on youtube I get the following data for rough approximations:

Jetpacks will burn bringing an assault marine to approximately 15 meters of height in 1.4 seconds. From the apogee of their jump, they can trigger another burn, bringing them back to the ground at -45 degrees in about 0.4 seconds.

The initial jump is parabolic but it should come out to roughly ~10.7 m/s. This is about 24mph if I'm doing math properly.

By comparison, if we assume straight line, we should get a hypotenuse of 21.2m, which means we get a constant speed during descent of 53m/s which is about 120mph.

Again I'll take better measurements at home, but make of this what you will!

[Dlatrex]

Ok, as promised I took some data once I got home (the wife has no idea while I need a stop-watch to play this game).

It looks like a static jump reaches about 18m in 1.45 seconds...so revised the average jump speed to 12.4 m/s or 27.7 MPH

The dive attack will cover up to 21m laterally from the peak of his jump, so a direct 27.6m covered in 0.5seconds. Should be 55.31m/s or 124mph.

These were taken from the multi-player. I believe the single player allows for higher jumps, but similar velocities.

Cheers!

[Tynskel]

we are definitely talking about an 'average' car crashing into you at 30mph. That's some serious whompage!

[Nabterayl]

It totally is, but it doesn't create a meaningful shockwave. Get hit by it, there's a good chance you'll be injured. Get pinned by it against a wall (or the ground, whatever), you'll be fatally injured if not killed outright. Get missed by it, even by a few inches, you're just startled, maybe cut by some rock chips if the impact is against rock. That's true whether the marine is moving at 20 mph or 120.

[Dlatrex]

I'm inclined to agree. Any other effects would seem to be attributable to special arms, armours, or rule-of-cool! I guess this does in fact line up reasonably well with the hammer-of-wrath mechanic in the end.

[Tynskel]

yeah, hammer of wrath is clearly, even from the description, a body mass hitting body mass thing.

I chock up the shockwave to Captain Titus being a bad mofo. Although, I am not surprised by a shockwave when you dive with a Thunder Hammer.

Also, remember, taking a wound in 40k doesn't mean you are dead. It means that you are incapacitated (probably dead!). Getting hit by a car at 30mph will incapacitate most things for at least the duration of the skirmish.



I am also curious about those numbers... You look like you jump about 20x the height of the space marine. That's 40 meters in 0.5 seconds...

[daboarder]

Apparently a cat has a non-fatal terminal velocity as long as it falls from above 6 floors, (I wonder if that's our six floors or your six floors?) but it needs that much distance to ensure it's feet down when it lands...

Interestingly enough, humans have a potentially non-fatal terminal velocity. Provided you get lucky about how you land and don't land on say concrete.


What do you mean by an inertial compensator? You could put shock absorbers on the knee joints to stop your legs going into your lower intestines, but you'd still shatter every bone below your knee. And if the armour lacks padding, it will do absolutely nothing to stop massive damage to internal organs from the impact. Put simply, humans have precisely no evolutionary adaptations to help with hitting the ground at speed. Being an abnormally large human in heavy suit of armour does not improve this situation.

This: the principle of conservation of energy is why I find it hillarious that mauls are AP4.

war hammers and mace's were developed because the fact that they use impact to create damage means that they transfer the full force of a blow through armour, ignoring it completely and in some cases (head wounds) the armour amplifies the effect of the force.

[Tynskel]

And they do so. Full plate was designed to take a maul to the head, ie power armor. Everything else would get squished.

[Nabterayl]

I actually think the way they handled power weapons was ... adequate. Armor protects against concussive weapons, just not as much as it protects against bladed weapons - having the force of a warhammer concentrated on an area of your body the size of the hammer face is certainly worse for your tissue than having that same force concentrated on an area the size of the armor plate. So a power maul's high Strength makes it a better choice than a bladed weapon for harming those protected by heavy armor. The only question is why an axe would be AP2, and I think the rationale for that is that a power field still cares about momentum and area. Smash a power maul into a ceramite plate and it creates a dent before the hammer face contacts the plate and the power field deactivates, though transfers some amount of force to the object behind the plate as well. Smash a power sword into a ceramite plate and it slices through it, as long as it isn't too thick - in which case it doesn't have the momentum to cut all the way through before it comes to a stop. A power axe transfers less force to the object behind the plate, but the head carries more momentum than a sword of equal weight and is thus able to penetrate a greater thickness of plate.

Thus, absent the effects of the power field, a maul would be better than an axe would be better than a sword for wounding a man in armor, as it should be. Add in the power field and I think they modeled it well.

[Dlatrex]

I am also curious about those numbers... You look like you jump about 20x the height of the space marine. That's 40 meters in 0.5 seconds...

I think the view from altitude is deceptive. If you're talking about jumping straight up from 'ground level' at full burn, and spotting the jump using land-marks in game, I get a maximal jump of 8.5 x marine height. One of the game resources lists Titus as 7'2" so going from there, it looks like ~ 60 feet ~ 18meters. Let me know if there's a situation where you can get it higher than that!

[daboarder]

And they do so. Full plate was designed to take a maul to the head, ie power armor. Everything else would get squished.

no!, no!, no!

Sorry about that you need to catch silly misconceptions quick.


Full plate was designed to protect the wearer from swords and axes

Then knights started to use concussive impacts to bypass the protection.

Don't argue mate its one of the simplest laws of physics, in fact.

http://www.youtube.com/watch?v=fWSgm5aMsbU

Your head is the middle ball. In accordance with the laws of physics all the energy is tranfered through the system as a wave. When you take into account the concave nature of the inner curve of the helmet you get superimposition of the waves right where the persons brain is.

Its like sitting with you head in a bell when someone rings it.

More nails for the coffin


War hammers, especially when mounted on a pole, could damage without penetrating the armour. In particular, they transmitted the impact through even the thickest helmet and caused concussions.

[Psychosplodge]

Aye and ten they used the spike on the back to finish you of...

[Tynskel]

no!, no!, no!

Sorry about that you need to catch silly misconceptions quick.


Full plate was designed to protect the wearer from swords and axes

Then knights started to use concussive impacts to bypass the protection.

Don't argue mate its one of the simplest laws of physics, in fact.

http://www.youtube.com/watch?v=fWSgm5aMsbU

Your head is the middle ball. In accordance with the laws of physics all the energy is tranfered through the system as a wave. When you take into account the concave nature of the inner curve of the helmet you get superimposition of the waves right where the persons brain is.

Its like sitting with you head in a bell when someone rings it.

More nails for the coffin

Oh, you don't need to explain to me the shockwave physics and spallation. However, I believe you have this wrong. The helmet of full plate had multiple layers of different types of materials, not just metal, disrupting plate impacts. This is actually very similar to how bomb armor works, and modern tank armor too. The different materials cause disruptive interference.

If you look at the history, knights switched to two-handed swords, and ditched shields, because full plate protected them against almost all weapons except, essentially, two handed sword (and later, the longbow). The two handed sword was used with leverage to work its way into the vulnerable areas of the armor (neck, armpits, crouch). You would grab your weapon at the 'half' and hold maneuver the pommel until you pierced the weak point (usually destroying a major artery).

[Nabterayl]

I don't think daboarder is arguing that plate didn't protect at all against concussive blows (at least, he shouldn't). If you're going to be hit by a warhammer, whether in the chest or the head, a solid or glancing blow, you're better off in harness than out. You might be incapacitated anyway (a solid warhammer blow to the head can still scramble your brains no matter how good your steel and the padding behind it), but you're still better off than you would have been.

I think what daboarder is trying to say is, if you are going to attempt to incapacitate a man in full harness, concussion is the best wounding mechanism. Surely there's no debate about that? Two-handed swords, as you know, were in military use long before the medieval use of plate armor. Half-swording was a technique to adapt an existing tool to new kinds of protection, and it was effective, but that doesn't mean it was the most effective option. There's a reason the knightly weapon par excellence was the poll axe. Swords are like lightning claw terminators: they're for killing things you already hideously outclass ;)

[Tynskel]

I think the view from altitude is deceptive. If you're talking about jumping straight up from 'ground level' at full burn, and spotting the jump using land-marks in game, I get a maximal jump of 8.5 x marine height. One of the game resources lists Titus as 7'2" so going from there, it looks like ~ 60 feet ~ 18meters. Let me know if there's a situation where you can get it higher than that!

I have been watching some youtube videos, and I am pretty sure you are going much more than ~10x marine height. If you are looking up, you go higher than if you are looking down.

It also looks that if you use the maneuvering jets in combination of looking up and then targeting an area far away, you can get going reallllllllly fast.

[Dlatrex]

I have been watching some youtube videos, and I am pretty sure you are going much more than ~10x marine height. If you are looking up, you go higher than if you are looking down.

It also looks that if you use the maneuvering jets in combination of looking up and then targeting an area far away, you can get going reallllllllly fast.

Here is the data I gathered.

First how tall the marine is against the brick wall. Then how high along the wall I was able to jump with a full burn.
http://farm9.staticflickr.com/8324/8140068569_a068ecbf04_c.jpg

And here is a wide shot to keep everything in perspective. The Marine i used was a little hard to see against the background, so I have enlisted an ultramarine to make it more apparent.

http://farm9.staticflickr.com/8054/8140099302_8340317b3f_b.jpg

I was actually being generous as you can see it's only 8.5 marines if you include the marine at ground floor. Actual distance moved is closer to 7.5 marines high.

As to what you were saying with the angle of decent, it is true that you can get some crazy distances depending on if you're in single player or multi-player, and certainly jumping from a higher starting level to a lower level. That said, it does not appear that you continue to accelerate over the extent of the jump, so even measuring a shorter jump (like I did from a static height) we should be able to get the speed pretty accurately.

[Nabterayl]

More spitballing ...

The right-triangular jump-and-dive that Dlatrex describes is 27,224.9 kg·m/s of momentum, which requires a total of about 13,961.5 N to accomplish over the observed 1.95 s (somewhat more than that since some of the thrust is countering gravity). If that is in right ballpark for how much thrust the jetpack can generate before needing to cool down/recharge/whatever it does (and I know that figure is going to be low, since I think we can observe longer jumps and, in particular, longer powered dives), we're dealing with a 60-second sustained burn of approximately 453.7 N, or 1.1 m/s^2 sustained 60-second acceleration.

That's certainly low, but if it's even in the right order of magnitude, even THQ is presenting jump packs as slow for sustained burns, and fast for very, very short burns.

[Tynskel]

130mph is pretty fast!

[Nabterayl]

Sure, if you're accelerating in mid-air, but I can't imagine what use 1.1 m/s^2 acceleration would be other than to slow a descent (or I guess speed a really long descent). That isn't even enough to get you off the ground.

[DarkLink]

It's closer to steampunk in that sense (skullpunk?). While it is silly that technology tops out at about the 1940s, internally it hangs together.

Gothicpunk.

[Tynskel]

More spitballing ...

The right-triangular jump-and-dive that Dlatrex describes is 27,224.9 kg·m/s of momentum, which requires a total of about 13,961.5 N to accomplish over the observed 1.95 s (somewhat more than that since some of the thrust is countering gravity). If that is in right ballpark for how much thrust the jetpack can generate before needing to cool down/recharge/whatever it does (and I know that figure is going to be low, since I think we can observe longer jumps and, in particular, longer powered dives), we're dealing with a 60-second sustained burn of approximately 453.7 N, or 1.1 m/s^2 sustained 60-second acceleration.

That's certainly low, but if it's even in the right order of magnitude, even THQ is presenting jump packs as slow for sustained burns, and fast for very, very short burns.

I am not sure how you are calculating the 1.1ms-2, because it is quite clear that the jump pack is never used that way.

[Tynskel]

Whee!
Go Space Marines!

http://www.youtube.com/watch?v=gCVt9rRE0bk

[Nabterayl]

I am not sure how you are calculating the 1.1ms-2, because it is quite clear that the jump pack is never used that way.
Just spreading out the thrust exhibited in Dlatrex's jump-and-dive over 60 seconds instead of 2. All the source agree that you can't push a jump pack for true flight, but you CAN push it beyond the normal short hops that jump troops make once grounded.
Assuming a pack can only put out a fixed amount of thrust before it has to recharge, I was wondering what kinds of acceleration a THQ jump pack could produce over a minute (within a factor of 10 to provide a generous margin of error).

Just spitballin', like I said.

[Dlatrex]

What do you mean by an inertial compensator? You could put shock absorbers on the knee joints to stop your legs going into your lower intestines, but you'd still shatter every bone below your knee. And if the armour lacks padding, it will do absolutely nothing to stop massive damage to internal organs from the impact. Put simply, humans have precisely no evolutionary adaptations to help with hitting the ground at speed. Being an abnormally large human in heavy suit of armour does not improve this situation.

I just finished reading Deliverence Lost, and I thought it worth noting that Gav Thorpe does throw some numbers at us:


...The roof of the compound was 23 meters below, a distance that proved little problem to a fully armored legionary even in normal gravity...Clouds of dust billowed up as Alpharius landed on the pitted rockcrete roof. The fibre bundles in his armor bunched as he landed, a sudden flicker of system reports scrolling past his right eye...

Now while they specifically mention his armored status to say it is no problem, it is not perfectly clear if that it is meant to be easier or more difficult as a result of the extra weight of the armor. The implication by the rest of the passage seems to be that the armor helps absorb the impact from the landing.

Falling 23 meters on earth should give us a free fall time of t = SQRT (2*23m/9.81m/s^2) = 2.16s which should give us a speed at the time of impact of ~21m/s.

They also cover running speed in part. At one point when they are trying to cross a span of >260m, Corax gives them a time of 43seconds and fully expects them to cover it by 'sprinting'. They are able to clear it, although the marine with carrying the multi-melta just barely makes it, and is explicitly slowed by the heavy load. That gives us a minimum 'running' speed of ~6m/s for the slow-poke heavy weapons guy; which is equivalent to the walking speed of a marine in the game.

I don't know how much time Gav thought about his figures, but at least that gives us something to weigh out. :rolleyes:

[Wildeybeast]

Threadomancy! For all we know, Gav is pulling figures out of his arse, so I wouldn't put too much stock in it. I don't understand the maths, but so far as I see, the point I made remains the same. Your ankle joint is simply not designed to absorb any kind of fall from a significant height. The only conceivable way to avoid massive internal trauma would be something along the lines of the Masterchief's gel layer inside his armour which is capable of absorbing the impact force whilst transferring little to none of it to his body. I'm not sure if such a substance exists and IIRC correctly, there is no mention of any such thing in marine armour. I think this is one area where science fiction has to ignore science fact in order to make a good story.

[Dlatrex]

You're almost certainly correct. I wonder what the anatomy of an up-structured ankle would look like, to deal with the type of forces we've been discussing. Hmmm...

[Kyban]

In this case the armor's ankle could be designed to take the force instead of the occupant's, though I'm sure an astartes ankle is probably capable of quite a bit on it's own.

[Jmaximum]

I hear that (due to a weird way fall damage works at very low character levels), starting characters in the Deathwatch RPG can easily die from falling down the stairs :P

LOL if any of you guys have read the any of the Nth editions of the 40K rulebook, ANY space marine is susceptible to DYING from simply tripping over a tree branch (difficult terrain tests, anyone?) unless they have a special rule known as 'walking carefully'. Difficult terrain checks should NOT apply to Space Marines. There have been so many instances in the novels where a Space Marine simply makes a door in a building by running through the wall with complete disregard for the rebar and internal supports. It blows my mind when power armored giants approach a gentle rise in the ground and it's like "Oh, be careful guys, you might trip and break your neck on that"

[bfmusashi]

LOL if any of you guys have read the any of the Nth editions of the 40K rulebook, ANY space marine is susceptible to DYING from simply tripping over a tree branch (difficult terrain tests, anyone?) unless they have a special rule known as 'walking carefully'. Difficult terrain checks should NOT apply to Space Marines. There have been so many instances in the novels where a Space Marine simply makes a door in a building by running through the wall with complete disregard for the rebar and internal supports. It blows my mind when power armored giants approach a gentle rise in the ground and it's like "Oh, be careful guys, you might trip and break your neck on that"
It's not that the trip kills them, it's them falling into mud and being unable to get back up until the battle's over.

[daboarder]

LOL if any of you guys have read the any of the Nth editions of the 40K rulebook, ANY space marine is susceptible to DYING from simply tripping over a tree branch (difficult terrain tests, anyone?) unless they have a special rule known as 'walking carefully'. Difficult terrain checks should NOT apply to Space Marines. There have been so many instances in the novels where a Space Marine simply makes a door in a building by running through the wall with complete disregard for the rebar and internal supports. It blows my mind when power armored giants approach a gentle rise in the ground and it's like "Oh, be careful guys, you might trip and break your neck on that"

What are you talking about?

Difficult and dangerous terrain checks are two different things, difficult represents the model moveing carefully in an area for any number of reasons such as poor visibility, poor footing, an attempt to maximize the cover granted by the terrain and so on.

Dangerous terrain is for things like acid rivers, giant carnivores or potentially cooking off munitions from a burning tank husk.