What are Issues of Transforming Robots or Robots that Combine into Bigger Mechs?

[Johnny1A.2]

Originally Posted by Disliker of the mary sue

I know in general a Mech is a bad idea on many levels, cost, engineering, it's effectiveness versus other more conventional war vehicles. I also know that making a robot like a transformer that turns from a car to a robot, or something like a megazord where a bunch of Vehicles turn into one giant robot are also even more unrealistic ideas. But I don't know why in specific it is a really bad idea, the transformer and the make a bunch of vehicles turn into giant robots I mean.

It's a bit more complicated than that. It depends on what you mean by the word 'mecha'. For example, there are situations where a legged vehicle has advantages over wheels or tracks. I can easily imagine certain situations where a vehicle with a leg propulsion system and robotic arms could be genuinely useful, especially in higher-tech situations.

But it's very hard to imagine a situation where that vehicle would be shaped like a humanoid, or much like an animal. It wouldn't look like a mechanical living creature, it would look like a vehicle with legs, if you see what I mean. You could call that a mecha, but it's not what is usually meant by that word.

Is it completely impossible for even like a realistic higher tl level beyond our own (not super-science) or is it just too much of a engineering nightmare for anyone to even seriously consider (and fund) such a thing? More or less just setting brainstorming in case I ever do get to set up a mech campaign.

'Impossible' is a big word. Lots of things are technically possible, but still utterly impractical. Combining mecha (or robots) is a good example.

Let's take a fictional example: the Shogun Warrior Combatra.

Combatra in humanoid mode is a human-shaped mecha several stories tall. It is made up of five subvehicles that can merge back into a giant humanoid robotic mecha. Besides the issues of physics involved (the square-cube law applies to machines as well as living things), there are various practical considerations.

Combatra was able to be divided up into five separate vehicles with offensive capabilities; Delta-V One (its head), Skyskater Two (its chest/thorax), Earthmover Three (lower torso), Turbostreaker Four (its legs and pelvis) and Groundrover Five (its feet).

Let's say the pilot splits up Combatra to attack the enemy from all sides. They defeat the enemy, but in the process let's say Groundrover 5 gets heavily damaged, as does Skyskater Two. Fine, now the pilot wants to put the parts back together into Combatra...but the feet and upper torso are damaged, which means the head and lower torso can't connect properly, and the feet are damaged, and the reintegrated giant mecha can't even stand up. Damage to one element of the set makes the combination impossible or useless.

Same deal with combining Transformers like, say, Devastator. If something damages one of the five robots that make up the combination, it's hard for Devastator to come together at all.

To go back to Combatra...why would you want to combine the vehicles at all, other than Coolness? If the pilot can control the other vehicles/components by remote control from the head module, (IIRC in the comic AI was involved as well), there's no obvious reason to bring the swarm together at all, they're much more effective in their own specialized roles, working as a team.

It might make sense to link them together for transport...but the humanoid shape makes no sense then, it's aerodynamically lousy and forces weird design constraints on the individual components.

You might want to link them together when not in battle to reduce data load and simply controlling the whole thing...but again, the humanoid shape is pure nonsense for that.

Now, just as legs on a vehicle can make sense in certain situations, combining vehicles can be plausible for certain uses, too. But they won't be like combining mecha. For ex, I could imagine an aircraft, at a high tech level, designed to be combined with a booster stage able to get it into orbit or enable it to reenter safely, but which could be left off for ordinary use. The control system for both elements could be in the aircraft, the cockpit of the aircraft would also control the booster section.

That would be a 'combining vehicle', but not like Voltron.

Likewise, something a little like the Fantasticar, with its detachable side-pods, might be buildable and might even have some use. But note the lack of a humanoid shape.

The same general deal applies to 'transforming' vehicles. There might be some situations where a transformable vehicle could be useful. But it would be heavier than an ordinary vehicle, and the engineering necessities of building a machine able to work in multiple shapes or multiple environments would make the vehicle heavier and more expensive than one specialized for a given use.

What would such a vehicle be used for? Well, if you're mass-limited, it might be better to carry one transforming vehicle than an airplane, a car, and a submarine, assuming you could build the transforming machine. A spaceship going might carry one transforming shuttle rather three separate specialty vehicles, to save on total weight. The transforming vehicle would be heavier than any one specialized vehicle but lighter than three of them. Or if you don't know where you might need to go, the versatility might be worth the performance penalty.

But for a given tech level the specialized vehicle is likely to outperform the transforming machine in its environment. The airplane will outperform the T-machine in the air, the car on the ground, and the submarine in the water. If you want a transforming vehicle that outperforms a specialized one in a given environment, you need to assume that the T-machine is several tech levels more advanced than the specialized one.

But the transformer also has a weakness in common with the combiner. Let's say my T-machine is underwater in sub mode, and takes some minor bit of damage, that just happens to be in a component that has to move around or change shape to change over to air mode. All of a sudden my expensive and heavy air mode systems are dead weight. Plus, the extra complexity of all these systems and their tranformations adds to cost and weight and things that can go wrong.

And it still pretty much never makes sense for one of the transformation modes to be human-shaped.

So legged machines are a valid design choice for certain situations, and combining machines, and transforming machines, can make sense under certain circumstances, but have downsides. Humanoid transforming and combining mecha make no sense for any purpose other than Coolness, and like most Cool things, they make no sense when looked at coldly.