I noticed watching Age of Ultron, when the Hulk and Tony are fighting, that the Hulkbuster suit is much bigger than Tony is.

Obviously in the regular Iron Man suits it fits around his arms and legs and he can move them around using his own limbs.

But from the size of the Hulkbuster suit he must surely only fit inside the torso of the suit.

In Avengers 2

when the Hulk shoves a lamppost through the shoulder of the Hulkbuster suit, the fact that Tony doesn't lose his arm/hand shows that his limbs definitely don't reach that far.

So how does Tony control such a massive suit? It shows the Hulkbuster suit covering his regular suit, so is the smaller inner suit like some sort of controller for the larger outer suit?

I would say maybe the torso is hollow and he's moving around in there and the outer suit is following his movements (Real Steel style), but from the hits he receives from the Hulk the torso would surely cave in if it was hollow.

Is it ever explained in the comics? If not, does anyone have a speculative answer?

  • 8
    How does Tony Stark control the Hulkbuster Suit? Very well, thank you. Commented Apr 30, 2015 at 12:05
  • 6
    The regular Iron Man suit clearly "amplifies" his movements; he is stronger in the suit than out of it, for example. There's no reason to assume that the same control signals couldn't then be passed on to the Hulkbuster exoskeleton. And no, it's not hollow around him - it's a Iron Man-suit-sized central cavity surrounded by the armouring, motors, etc. for the Hulkbuster.
    – jonrsharpe
    Commented Apr 30, 2015 at 12:22
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    "but from the hits he receives from the Hulk the torso would surely cave in if it was hollow." Are you suggesting that the regular Iron Man suits derive their strength from the fact that there is a puny human being inside them taking up space?! Commented Apr 30, 2015 at 16:33
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    @Mike.C.Ford: I don't see why. His regular suit is hollow, too, otherwise he wouldn't be able to get into it. What difference does it make that his body no longer fills the whole suit? Commented Apr 30, 2015 at 16:49
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    Op means hollow as in not form fitting to the inner suit...
    – user16696
    Commented Jun 20, 2015 at 17:02

6 Answers 6


Tony stark uses something that's called brain computer interface that translates brain EEG signals to control machines. So if Tony needs to move the suits arm he just needs to think of moving. This technology currently is very slow and not advanced as Tony has but it might get to that level in future. The electrodes of the EEGs are shown in avengers and Iron Man 3 many times.

Tony Stark wearing a headset that seems to be reading his brainwaves with sensors on his brow and cheekbone

  • 1
    He hasn't needed external electrodes since Iron Man 3 at the very latest. Commented Apr 30, 2015 at 16:34
  • This eeg electrodes I'm telling about and its already inside his helmet and is shown in avengers 1 when Thor removes his mask.
    – user93
    Commented Apr 30, 2015 at 16:53
  • Yes, I am aware of that. I am pointing out that between Avengers 1 and 2, the need for these EEG electrodes has gone (during Iron Man 3, at the latest). Commented Apr 30, 2015 at 16:55

This makes sense. See the image below of how Tony Stark's Ironman would fit inside the Hulkbuster suit.

A cutaway  image of Ironman inside the Hulkbuster suit with surrounding text in Portuguese.

  • You've provided some information but it doesn't really say how it moves it, also this is in Spanish. I don't mean to go against any languages, but this site primarily operates in English.
    – Edlothiad
    Commented Apr 13, 2017 at 13:55
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    If this was real technology, it would be worth discussing. However, I thought I'd at least provide a section-cut image of how Stark actually fits inside the suit. The rest is futuristic, comic book technology. Enjoy.
    – SMOdaddy
    Commented Apr 13, 2017 at 14:04
  • Does anyone have an English version of this?
    – iMerchant
    Commented Apr 13, 2017 at 17:52
  • 1
    @Edlothiad I believe that's Portuguese. Commented Feb 23, 2018 at 22:04
  • @Azor-Ahai the language it is doesn’t matter, the fact it’s non-English does.
    – Edlothiad
    Commented Feb 23, 2018 at 22:20

Tony has always used a Brain-Computer Interface to use his suits.

The suits limbs are sufficiently heavy that a human hand/leg wouldn't be able to move it by themselves. The suit reads the users brain-waves & accordingly translates them to move the suits parts Exactly as the wearer does.

This sync has been perfected in Tonys suits since Mk1. A lack of this is seen in Iron Man 2, where Justin Hammers suit experiments show up & his suit twists the wearer completely at the hip. This is the result of improper wearer-to-machine translation.

Extrapolating from this, Tony doesn't really need to have his physical limbs placed inside of the suits parts to make them move. Think of it like a very-very-very high tech prosthesis :P


So how does Tony control such a massive suit? It shows the Hulkbuster suit covering his regular suit, so is the smaller inner suit like some sort of controller for the larger outer suit?

It could be hollow if the outer shell was subsequently thick enough, but anyone with enough knowledge on the subject to answer the question would know how big the suit is, and therefore know that in order for there to be room for Tony to swing his arms around, the outer shell of the suit would have to be reasonably thin, which I'm guessing would not be adequate protection.

Why would he need to swing his arms around? You can't swing your arms around indefinitely anyway: you have a fixed range of motion. The suit can simply translate a small motion into a much larger motion. This appears to be how Stane's Iron Monger suit worked in Iron Man.

In reality, I suspect what makes the most sense here is use of the neural control interface introduced in Iron Man 3; now Tony, inside the suit inside the suit, doesn't have to move at all! I can see that being slightly unintuitive to use, but you'd get used to it: Tony certainly did while remotely piloting the Mark 42 from the back of a lorry (as he wasn't exactly running around in there).


The same way, the armour Obadiah Stane uses in Iron Man I is a lot greater than him.

AFAIK there's no such explain on canon, however, from an engineering point of view, probably the suit is something like an exoskeleton projected on a greater size.

Tony would probably get suited in a way very similar to which he is in the "ordinary" armour, but there are lot of servos that traduce his movements to the bigger limbs of the hulkbuster.


Based on the size of the hulk buster and the regular iron man suit, Tony is likely in a sitting position, like a fighter pilot. From the movie we know it is form fitting near the head, so not a large hollow cavity, Pacific Rim style.

Note the Iron Man 3 Air Force 1 Scene. At the end of the scene, Iron Man is in a straight flying position, head tilted up, arms at the side. Then a truck takes him out and it reveals that Tony is in a cramp boat cupboard, arms out like he's holding a pilot stick, face forward. That is, his position doesn't match the suits, so direct physical movement matching is not needed. Brain wave interface does it all.

Finally, even the regular iron man suit can't really move without power, as we also see in Iron Man 3. It weighs alot, and if the servos arnt powered and mmoving in response to user input, they can't be moved, they lock up.

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