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Post by Dazo on Apr 8, 2005 5:06:21 GMT -5
Whats that mean when translated into english This is turning into another thunderhawk flying brick discussion, yes retro rockets would be used cels can't agree more, but also the fact remains they are always described as making a crater when they hit so they must still be travelling at some speed. Now I can't remember where, but it is in one of the books that something else is used to help cussion the fall....it was in fact a gelatinous chemical foam. And the marines still blanked out for a second, so take what you will from it.
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Post by Briareos on Apr 8, 2005 5:44:01 GMT -5
As a pointer for futur discussions, here's a short, official description of the drop pods and their deployment from Epic Armaggedon :
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Post by Tynesh on Apr 8, 2005 6:17:52 GMT -5
Maybe it would be best to first work out the calculations on what would make the pod survivable to a normal human. This would give us an idea on the basic levels of stress that one would encounter hurtling downward, slowing very fast and then hitting the ground with a bump. If we know what was survivable for human we could make a slightly larger estimate for what a marine could survive. I don't think that it would be much more that 15G maximum, remember they have to burst from the pod four seconds after impact, bolter firing and chainswords whirring!
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Post by Tim_C on Apr 8, 2005 15:54:41 GMT -5
I would volunteer to do that, but I've been thinking about it, and assuming the pod describes a parabolic flight path from a battle barge 200km above a Terran-style world the calculations would start to get complicated, especially if we started to include air resistance. The parabolic motion equations are easy to find (google for general parabolic motion equations or similar), but with air pressure and density changing all the way through flight, we could end up with a massive integration to perform, particularly if we have the marine as a rigid body within the exterior body of the pod... Suffice to say my brain was going to explode. Doing this bit of research did throw up a couple of interesting points though... Firstly, it's a good thing the pods have fins to control their flight path, as drop pods would move a huge horizontal distance whilst passing through the atmosphere if they were simple rigid bodies (we're talking thousands of kilometres here) Secondly, the 12000kph mentioned in IA Vol 2 can't (strictly speaking) be a constant velocity from launch to impact, otherwise you'd get the massive forces described earlier (btw E+07 means seven zeros, so 1.5E+07 means 15000000 GPa) and your marines would be turned to mush on impact. So, even if we assume initial velocity of 12000kph (vertical velocity) then we're still travelling at a massive speed. I'm not writing the maths out (mainly because I haven't got my old notes and I can't remember half of it), but I think it'd be similar to the old 'falling lift' theory. So, where do we go from here? I'll probably write something later, when I can actually think straight (Engineering mixed with accounting statistics is never a good state of mind)... ;D Tim
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Post by CELS on Apr 8, 2005 16:17:03 GMT -5
Well, that's a fair start! Looking forward to your next post, Tim And no, drop pods will definitely not be hitting the ground at 12,000 km per hour. We already know that they slow their descent by retro rockets, and if you believe the intro sequence from Dawn of War, they're definitely not going faster than 400 km per hour. Of course, you have to account for artistic license. To be fair, the Dawn of War video sequence doesn't really show the retro rockets. If you want to give that video credibility, the idea is that drop pods slow their descent at a certain altitude, before turning off their retro rockets and falling to the ground. Then again... the drop pods seem to be moving extremely slow on that video... If it's not retro rockets, then perhaps grav engines, similar to the ones on Land Speeders? Land speeders are also deployed from high altitudes, sometimes.
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Post by Philip on Apr 9, 2005 5:49:53 GMT -5
Well, looking at it from Kage’s point of view by ignoring the image (go figure) we could have a relatively low tech version for the drop pod for Anargo project.
Air resistance is going to slow the drop pod down dramatically, and it will slow down until it reaches terminal velocity (for a human this is about 200 kph taking air resistance into account). This is what basically happened to the Apollo re-entry module.
So the drop pod would be travelling at around 200-300 kph and the retro-rockets could brush that off in no time. The actual impact would be negligible, a mere bump say 10-30 kph.
This is a perfectly functional and reasonable design for a ‘drop pod’ - but it doesn’t 100% match the 40K image. This is a very different dynamic to ‘meteors smashing into the ground’.
We could build one of these ‘mundane’ drop pods now, as they require virtually no sci-fi components.
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Post by Kage2020 on Apr 9, 2005 11:22:05 GMT -5
Well, looking at it from Kage’s point of view by ignoring the image (go figure)... Oh, I'm all for image. Just sensible image and not the approach where image is dominant and there just for the sake of it. This is the 'Imagery' and 'Rule of Cool' in operation. Leave it to your paid job. we could have a relatively low tech version for the drop pod for Anargo project. Question is whether they are re-used or not. The more uses you get out of something the more 'high tech' it can be. But given the common imagery - ha! - in more developed genres with regards to 'drop troops' it would seem fairly reasonable to go with the 'cheap' premise. This is a very different dynamic to ‘meteors smashing into the ground’. Which is essentially naval lint. I don't mean that in a bad way, merely that it is the reason that the 'fluff' is called as such. Images that conform to that are 'fluff' for the same reason... Again, image tempered by reality, not reality changed to fit the image. That is the stance that I generally take. As to the crater... Is it really 'reasonable', or do we have to invent some 'sci-fi' component to explain mal-imagery? (E.g. This is not meant in a negative light, but the whole 'power fields' around officers heads to explain why they don't wear helmets rather than just going, "Well, it looks cool in the pictures but you wouldn't really want to do that..." Is it 'mundane'? Potentially. But I'm a great fan of not using complex explanations if simple ones will fit.) Kage
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Post by Philip on Apr 9, 2005 11:55:51 GMT -5
As to the crater... Is it really 'reasonable', or do we have to invent some 'sci-fi' component to explain mal-imagery? Reasonable? Is FTL drive reasonable? To put this in perspective, travelling faster than light is far, far more extreme that slamming a drop pod into a solid granite mountain at 100,000 kph and walking out alive. Yet nearly every sci-fi has FTL drives.
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Post by Kage2020 on Apr 9, 2005 12:08:28 GMT -5
I think that you're missing the point, Philip. There are some things that one has to assume - to suspend disbelief on - to make a fantasy/sci-fi universe work. But that doesn't mean you have to invent some spurious 'sci-fi gadget' to make every little piece of artwork (or narrative) work.
Imagery is meant to be evocative, not necessarily accurate.
Kage
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