Who needs tanks?

[copeab]

Originally Posted by blacksmith

Can most building support mecha on their roofs? And how is this different from any level of technology were infantry is king in cities?

I never said the mecha were on roofs. I said the infantry were on roofs.

Unlike a tank, a humanoid mecha can easily fire at infantry hiding in the upper floors of buildings. The Russians even built a vehicle with high-angle fire for supporting tanks.

THen they have a much higher profile than the tank, and it removes your earlier point. To be the equivalant of hull down the mecha needs to be prone and unlike a tank it can not back up it has to stand up thus exposing itself much more than the tank.

If a person can crawl backwards, I image a mecha could, too.

[copeab]

Without a consensus on tech assumptions, I don't think we're going to do much in this thread except talk past each other.

[Jonas]

Regarding the defects of combat mecha (not power armor), there's a few other issues that I can recall just off the top of my head that haven't been mentioned yet.

• Complexity: A mecha is going to require very strong yet flexible joints if its going to be of use as a war machine, while possible this isn't an easy task even before taking in account that they will have to be armored quite well due to their vulnerability. See Armor Density for how this will be much harder.
• Efficiency: The added complexity inherent to a vehicle with robotic limbs is going to increase the overall cost of production and maintenance for likely a fairly small gain in rough terrain performance and reduction in overall top speed. Yes, even when compared to the more numerous but comparatively 'dumb' joints in a track drive-train. Individual links in a track don't need to know where they are compared to the rest of the vehicle nor need to flex nearly as much outside of a 2d axis, not only making them stronger but simpler and more compact for a given stress level.
• Stability: Simply put, given equivalent tech levels and armaments the tank is going to be a more accurate and stable gunnery platform for all the same reasons a prone man is more accurate and stable compared to when they stand. Yes a mecha could also do the same by lying prone, but only at the cost of losing mobility while doing so and precious time to while it changes position where as a tank driver just needs to hit the throttle. Yes, that is even with more advanced fire control electronics as any advance in tech that makes a mecha more capable will also generally apply to tanks as well.
• Armor Density: If everything before wasn't bad enough, we finally come to the fatal flaw that can't simply be engineered out. This being the fact that all else being equal, a mecha is going to have a much greater surface area that it needs to protect when compared to the rolling armored box we call a tank. This means that in short for a given mass of armor a mecha has to be either spread much thinner or concentrated just the 'vital systems' leaving everything else at the mercy of your enemy much like modern fighter jets. The tank meanwhile, being the rolling armored box it is, possesses a shape that has a fairly decent internal volume compared to the surface area covered with the same mass of armor thus can possess an effectively higher armor density then any mecha could hope to have. Even with Btech style super magical armor this remains unchanged as the tanks still going to make better use of a given mass of armor.

[Ulzgoroth]

Didn't the OP say that armor is deprecated because of weapons with infinite armor divisor? That makes armor-bearing comparisons irrelevant.

EDIT: No, only partially, since if ECM can shut down grav-guns people will want alternatives.

[blacksmith]

Originally Posted by copeab

How is that misleading (thinking of mecha height as roughly equal to tank length)?

Well for one thing the mecha will be a lot lighter than the tank. Less well armored and likely with lighter weapons.

[blacksmith]

Originally Posted by copeab

I never said the mecha were on roofs. I said the infantry were on roofs.

You were ambiguous and discussing why mecha would great in a city. It is a logical inferance that you were refering to mecha on the roof.

Unlike a tank, a humanoid mecha can easily fire at infantry hiding in the upper floors of buildings. The Russians even built a vehicle with high-angle fire for supporting tanks.

Or just mount a high angle fire machine gun on the roof, or rockets or some such thing. The idea that a mecha must be able to fire at a higher angle than a tank is not something I see a good reason for. Asside from say a tanks main gun which is bigger than the mecha can carry anyway.

If a person can crawl backwards, I image a mecha could, too.

Very slow.

[blacksmith]

Originally Posted by Ulzgoroth

Didn't the OP say that armor is deprecated because of weapons with infinite armor divisor? That makes armor-bearing comparisons irrelevant.

EDIT: No, only partially, since if ECM can shut down grav-guns people will want alternatives.

If weapons dominate that much swarms of small autonomous vehicles would be the answer.

[blacksmith]

The only time I see a legged vehicle being used is for situations when a wheeled vehicle simply can move there, see afganistan for an example. And I would expect 4 and 6 legged weapons platforms not humanoid ones.

[copeab]

Originally Posted by blacksmith

Or just mount a high angle fire machine gun on the roof, or rockets or some such thing.

Still not as flexible as a weapon in hands.

The idea that a mecha must be able to fire at a higher angle than a tank is not something I see a good reason for.

It's a quite logical idea if the mecha has a hand-held (or even arm-mounted) weapon.

Asside from say a tanks main gun which is bigger than the mecha can carry anyway.

Maybe, maybe not. Depends on what you think a tank will mount in a setting with technologically feasible mecha.

[Joseph Paul]

One of the problems with hull down these days is that the weapons are getting to the point that they can fire through the protecting material and still destroy their target. US tanks shot through protective sand/soil berms to destroy Iraqi tanks.

In WWII sheltering from tank fire in a building was a good idea and in extended engagements fortifying a building made it into a strongpoint that was hard to conquer. Look into the Chemist's Shop and Pavlov's House at Stalingrad for examples.

I don't think that modern penetrators are being slowed adequately by modern industrial construction. Even small DU rounds may be able to penetrate several inches of concrete. That means that being hull down is no longer an advantage unless the terrain can be quickly fortified. It only gets worse in the future with rail guns and plasma weapons.

Tanks can't entrench themselves or build fortifications and even powersuited infantry have limits on what they can handle. Specialized combat engineering vehicles will help but you need several different kinds to handle dismantling concrete and placing it properly. It may be that mechs are versatile enough to do most of the heavy engineering and then fight from these fortifications.

Given that any armor can be overcome + the awesome accuracy granted by TL 9-10 gear is there a reason to invest in heavily armored tanks that can't dig in and hold?