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Evangelion Ideas Thread: You Can (Not) Rebuild

Yeah, strange as it is for me, I would echo @Dealer : Best don't give numbers. If you want EVAs in orbit, then they simply have rockets for that. I mean, the EVAs themselves already are NERV super-science, so why not the rockets as well? Plus, the weight of the EVAs surely has to be in the five digit tons area, so using RL tech limitations doesn't work anyway.

The thing is, in the series EVA dimensions aren't even consistent. In some shots, EVAs have a height of maybe 40m, in others of maybe 80m - always just as the visuals/the plot needs it. For example, most depictions of EVAs would be far too large to hold a human in their hands like EVA-01 did with Kaworu, but the plot demanded that. Only in Rebuild did they take care to have the EVAs always be 80m.

And weight/mass is never given and that for a good reason - EVAs are massive violations of the cube/square law. If you double a length, you eightfold the mass (2³), after all. That means IRL, EVAs would crumble beneath their own weight, or at least never be able to walk and jump like they do in the shows. That meas you can't really calculate a mass here, because EVAs are massively anti-physical in that aspect.

So you know, my advice: Just forget such calculations. You want to have them in orbit, do it. You want to create a difficulty, say they are too heavy. Whatever way you need it.
 
Few years ago, I did some calculations in this regard and came out at ~1400 tons as a low estimate, if we assume a similar average density as a human body and ignore the armor. Eventually I just decided to do what Susano said above and just don't give hard numbers.

Also, @sumghai... funny you get the idea of disposable reentry shells. I used the exact same thing with D-type equipment (based on the logic that with Evas being so big and un-aerodynamic, B-type equipment is likely not rated for atmospheric reentry) in my fic for the Ramiel battle (where the Evas didn't have access to sniping weaponry yet, so Unit-01 drew the Angel's attention with potshots followed by hauling ass away from the retaliation while Unit-00 dropped onto Ramiel from orbit to close in to throwing knife range faster than Ramiel can retarget once she's within auto-aggro range).
 
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Susano said:
And weight/mass is never given and that for a good reason - EVAs are massive violations of the cube/square law. If you double a length, you eightfold the mass (2³), after all. That means IRL, EVAs would crumble beneath their own weight, or at least never be able to walk and jump like they do in the shows. That meas you can't really calculate a mass here, because EVAs are massively anti-physical in that aspect.
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Is there anywhere I can find the hard data for about the size limit where mechs become physics defying?

Because a Hollow Bronze Humanoid Statue would be facing the problem of sinking into the ground, before it reaches the point where it would crumble under it's own weight, and even without unobtainium we have stronger materials than that available.

And yes, EVA's in particular are organic, but their structural support is a metallic exosksleton, and they are composed of exotic matter. Though I don't know if the metallic exoskeleton is as well.

So I was more wondering what would be reasonable for current metallurgy?
 
Matou Sutegobana said:
So I was more wondering what would be reasonable for current metallurgy?
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Well, of course we also have skyscrapers and the like - enormous buildings of 200m, 400m, more, and they don't crumble. But those are static. Way before you get problems of "collapsing under your own weight", you get problems of movement. Elephants already can't jump. A mecha with the same shape as a human still couldn't do the same movements as a human scaled-up, because of that pesky cube/square law. Which is also the reason why ants can carry the multiple of their body weight: We would also be able to if we were that small.

So that means there isn't a hard border. It's more like a gradual loss of efficiency. I think you could certainly build Battletech style mechs, which are in the order of 9-18m, but they would be slow and hulking and be generally so incredibly inefficient compared to tanks.
 
the original Rx-78 gundam, one of the smallest giant robots that can still call itself giant (barely 18m) has a density equivalent to styrofoam.

that should tell you a lot about the physics limits on giant robots.
 
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Dealer said:
the original Rx-78 gundam, one of the smallest giant robots that can still call itself giant (barely 18m) has a density equivalent to styrofoam.

that should tell you a lot about the physics limits on giant robots.
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The original Gundam, standing 18 meters tall, for 60t fully loaded, has a density of styrofoam? Are you sure about that?
Because even just eyeballing it it should come off as slightly below the density of water, or not that far off to the meidan density of a human body.

Now if you meant the Gundams from other seires, like Wing, those are about as dense as hydrogen, because a 18mt mech shouldn't weight 6 tons total.
 
Susano said:
Yeah, strange as it is for me, I would echo @Dealer : Best don't give numbers. If you want EVAs in orbit, then they simply have rockets for that. I mean, the EVAs themselves already are NERV super-science, so why not the rockets as well? Plus, the weight of the EVAs surely has to be in the five digit tons area, so using RL tech limitations doesn't work anyway.
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Fair enough - thanks for the pointer!

On a side note, I've definitely read elsewhere on teh interwebz that the Rebuild continuity EVAs were indeed quoted as 75~80 m tall (without / with pylons), so for the sake of internal continuity I'll use this number.
 
Flare said:
The original Gundam, standing 18 meters tall, for 60t fully loaded, has a density of styrofoam? Are you sure about that?
Because even just eyeballing it it should come off as slightly below the density of water, or not that far off to the meidan density of a human body.

Now if you meant the Gundams from other seires, like Wing, those are about as dense as hydrogen, because a 18mt mech shouldn't weight 6 tons total.
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yeah alright you got me, I was thinking of Wing Zero being 8 tons fully loaded.
 
Susano said:
Well, of course we also have skyscrapers and the like - enormous buildings of 200m, 400m, more, and they don't crumble. But those are static. Way before you get problems of "collapsing under your own weight", you get problems of movement. Elephants already can't jump. A mecha with the same shape as a human still couldn't do the same movements as a human scaled-up, because of that pesky cube/square law. Which is also the reason why ants can carry the multiple of their body weight: We would also be able to if we were that small.

So that means there isn't a hard border. It's more like a gradual loss of efficiency. I think you could certainly build Battletech style mechs, which are in the order of 9-18m, but they would be slow and hulking and be generally so incredibly inefficient compared to tanks.
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AFAIK human and elephant muscles use the same method of generating force, so they can generate roughly the same stress (force per muscle cross sectional area). This is where the "square/cube" law comes in, muscle strength scales with cross sectional area (roughly as height squared) while weight scales with volume (roughly as height cubed). You may well already know this, I'm just spelling it out for any readers who doesn't. It's technically possible to make something the size of an elephant that can jump if you have a muscle analogue that can generate significantly more stress. Based on the Eva's acrobatic displays, we can infer they must have vastly superior muscles.

The same logic applies to stresses on the Eva's skeletons, so the Eva's must also have bones with a much higher strength-to-weight ratio than human bone.

In summary, Angel bio-materials have to be bullshit hax for the Eva's to move as they do. Is that really a surprise?
 
sumghai said:
Fair enough - thanks for the pointer!

On a side note, I've definitely read elsewhere on teh interwebz that the Rebuild continuity EVAs were indeed quoted as 75~80 m tall (without / with pylons), so for the sake of internal continuity I'll use this number.
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Rebuild devoted considerable effort to making sure their size was consistent this time around:

And yes, their height would be... problematic. Internal considerations aside, picture what would happen when a say, 2000 ton mecha tried to take a step... when all that mass is balanced on the maybe 30 sq meters of their feet.
An Eva would be like a full grown man trying to walk across a sheet of wet rice paper suspended in the air. They'd punch through instantly, and drive themselves leg-deep. This would look rather silly.

And as mentioned, there's no way their weights could be anything reasonable. They'd have to be barely heavier than the Gundams, which are much smaller.
 
Yeah, Evas pretty much spit in the face of physics. But that's what they're supposed to do. If you want an anime about trying to engineer around the square cube law while building giant robots, go watch Robotics:Notes.
 
There is one idea I want, but it's a logistical nightmare.

Anime!Shinji meets Rebuild!Shinji. They become best friends, close as brothers. Much fun is had.
 
sumghai said:
Back with yet another hard scifi question!

What is the average mass and dimensions of an EVA?

As part of my story, NERV will have to respond to Angel attacks far outside of Tokyo-3 at a few hours' notice, sometimes halfway across the world, which necessitates some very fast global transport.

My current idea is putting the EVAs inside a hypersonic waverider transport lifting body that is then launched on a suborbital trajectory by some big dumb boosters; the waverider cruises the rest of the way with scramjets, before breaking apart like a piñata and dropping the EVA into battle.

IRL, most super heavy-lift launch vehicles can only take payloads of 50~100 metric tons to LEO, although the cancelled Sea Dragon and the proposed SpaceX BFR could theoretically do 400 and 500 tons to LEO respectively. I'm sort of partial to the Sea Dragon, as the design was already validated in the 60's and was explicitly designed to be built very cheaply at shipyards - potentially feasible for NERV to churn out replacements every few months.

Thoughts?
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NERV already have access to air transport for evas in form of big planes* (flying wing like designs), they were even used to deliver MP Evas in EoE.

*As in big enough to fit more than one eva inside one (they carry them externally, one per carrier).
 
aja318 said:
NERV already have access to air transport for evas in form of big planes* (flying wing like designs), they were even used to deliver MP Evas in EoE.

*As in big enough to fit more than one eva inside one (they carry them externally, one per carrier).
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Noted - however, I was looking for a faster form of transport that would not require an airfield/airport near Tokyo-3, hence my current idea of a rocket-launched suborbital hypersonic waverider pod.

I'd imagine the corresponding launch silos would actually be modified from existing catapult entrances located outside Tokyo-3 into an EVA-sized Vertical Launch System, complete with local propellant processing/storage facilities.


And now for something completely different...

Amongst the Evangelion community on Pixiv, I came across some fanart by ysouya, mostly Rebuild-related plus some alternative universe WAFF. I'm particularly partial to his Minjou High School series, a set of illustrations he did for an obscure fanfic community where (based on my lousy understanding of Japanese plus Google Translate) some collab fanfic writers took the alternative universe (?) ending of Sadamoto's manga and expanded it into a slice-of-life story about the Children now attending a prestigious high school, with primary ships being LAS* and LRK*.

*Japanese Evangelion fans refer to pairings of Shinji/Asuka and Rei/Kaworu as Love Asuka Shinji and Love Rei Kaworu respectively.


(source)


(source)


Valentine's Day (source)


Here's a fun one - apparently, the students in the dorm started a Karaoke competition, with Asuka pulling off an impromptu Hatsune Miku cosplay. Unfortunately, dorm manager Fuyutsuki decides the kids are getting too rowdy... (source)


Another group illustration, with cameos by Sumire Nagara and Midori Kitakami from the third Rebuild movie (source)

EDIT - Fixed 403'd images
 
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Wow never expected to see the characters from this angle.

Is it bad that the first feeling I get when I look at such stuff is cringe in fear of them being depicted wrong/badly?

Difficult to imagine them outside of NGE.
 
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