An engineering enigma: the useless "wings" behind giant robots.
"Bold design choice."
"What? I like anime."
"Worst-case scenario, we'll end up with the world's most expensive Gundam model."
―Tony Stark and Erik Killmonger
More than an aesthetic choice:
Mecha are a staple memorable aspect of Japanese media. Who doesn't love the sight of implausibly large robots duking it out? In some cases, the creators go as far as to take inspiration from real technology to make their designs feel more grounded in reality. If you know the saying "form follows function" you know where I am going with this. A common design choice in mecha is to endow them with little wings or spikes on their backs (look at the image above). I like details like these, it adds to the silhouette of the robots and makes them look more imposing. While I know it is just an aesthetic choice, I want to uncover their true purpose from an engineering standpoint.
Looking at the "wings" at face value, they do not participate in any sort of mechanical movement. Typically they move on an x y axis: bending up, down and shifting their angle sideways. Only in some instances do the wings serve as thrusters, usually backing up the main thrusters situated in the legs. The mecha desings tend to have exaggerated busts, possibly as protection for the core, so the wings may serve for balance? They do not seem particularly designed for being antennae either, the head would be a better placement I assume. That leaves us with cooling, which may be accomplished by multiple means. As a rebuttal for that theory we never see any exhaust from the spikes.
The real goal here:
If you have read this far without downvoting it means you are invested in the potential function of mecha "wings". My goal here isn't to ask a random question about giant robots. What I want is a functional application of these limbs to better design my own robots accordingly. Doing "whatever I think is best" isn't my style, I prefer facts and data that adds that sweet taste of realism to fiction.
[Edited] Wait... what were the giant robots used for again? Media portrays them as war machines. I'm using them for my robot designs, especially the larger robots. Their purpose is more mundane like as construction robots or as vehicles to explore hostile environments. The technology level is futuristic. Note that a "mecha" doesn't need to be skyscraper-sized, a human-sized machine can still be considered a mecha.
Answers should present a given function for the "wings" and explain WHY this design choice would be logical from an engineering standpoint.