As time has gone on, anti-tank weapons have become stranger and more dangerous to tanks.
In response, tank armour has become thicker and also more complicated.

Missiles can now try and attack where the armour is weakest, and variously punch, blast, burn and melt their way through. Typically these attacks rely on a fair knowledge of the armours weaknesses.

As a move in this red Queen's race, I propose low-density armour.
Firstly, this armour is thick. Really thick.
No, thicker than that.
To combat this size it has a relatively low average density. It is also formed in a 'sandwich' construction between a reasonably thick inner and very thin outer layer of conventional armour.

Although the density of the armour is low on average, it is heterogenous, meaning that it varies. It is mostly very low density, non-flammable foam but contains randomly positioned 'nuclei' which are high density. These nuclei may be near-spherical balls of metal, most of which are hollow or partly water-filled. The nuclei are sufficiently distributed that any incident projectile will hit multiple nuclei as it transects the armour. This absorbs and disrupts any concentrated attack it may have.

The idea is that the missile cannot predict what it will hit or when.
HESH rounds just stove it in slightly. Kinetic energy penetrators will bounce off several nuclei, changing their direction and losing energy. If not spherical they also start to tumble.
Shaped charge projectiles spend their attack on first nucleus impact, if not on the outer shell.

Further to this, the inner vehicle may not be positioned exactly centrally within the low-density armour bubble. Therefore attackers don't know exactly where to shoot.

Given that this enlarges the tank quite considerably, it favours deployment on very large tanks. Think of it as militarised cavity insulation.
-- Loris, Oct 12 2006

custard
-- senatorjam, Oct 12 2006


When you say "really large", what percentage of the total vehicle will be occupied by armor. Do you propose a ratio of 1 part naked tank to 5 parts armor, or even more than that?

I would suggest that the thin part of the outermost tank armor need not conform to the typical dull appearance of a military vehicle. One could use metal spraypainted styrofoam, paper maiche, or chickenwire and flowers to design large and fearsome (or perhaps funny and sympathetic) outward shells for these tanks. The sheer size of the decorative shell would help conceal the relatively tiny tank within.

I know, [21 Quest], probably the military is already doing that too.
-- bungston, Oct 12 2006


For some reason the vision of a tank looking like a head of broccoli came into my mind. If this stuff is really low density it would have to be very thick to dissipate the kinetic, explosive energy of the projectile. But if it is very thick it will make it almost impossible for the people in the tank to see and or swivel their weaponry. You could mount cameras on the outside of the armor but they would become the weak point and you still haven’t made machine gunnery easy. So it is back to the head of broccoli as attacks from above might be an effective use.

I could just see the Monty Python skit, “the broccoli is coming, the broccoli is coming”. Instead of “the buns are on the move sir.” Ooooo lunch time.
-- cjacks, Oct 12 2006


When you ask how thick, I have to say I don't know. I don't have enough information about the mechanisms involved. But we are talking meters. Yes this will massively increase the volume of the tank, so it wouldn't be suitable for narrow spaces. I imagine it would have a fairly round appearance. I did say it was for bigger tanks - but perhaps bigger than most/all tanks which exist today. The bigger the tank, the lower the surface area:internal volume ratio.

The tank could have almost-fixed guns and rotate to face the enemy. I think there was a Scandinavian tank with a fixed gun which did this.
When you ask about how the people inside see out, you raise a good point. A periscope perhaps?
-- Loris, Oct 12 2006


The S-tank, developed by Sweden. Great for defence, not so good in a mobile battle.
-- david_scothern, Oct 12 2006


I imagine there is always a weak point: entrance, fuelling point, exhaust (engine/ air con.), gun, wheels, tracks. etc.
-- Ling, Oct 12 2006


An interesting idea, however, I think in practice you'll find that it won't work as planned. The foam medium is likely to be a huge fire hazard, especially with the use of incendiary, white phosphorus rounds (BTW, most machine guns pack these things every fourth or fifth round as tracers). Non-flammable foam, says you? Thermite bomb, says I. The nuclei concept is very interesting, but the concepts of what you are talking about feel more like nuclear physics than ballistic physics. Also, you haven't taken into consideration timed fuses; there are quite a few shoulder mounted weapons that can fire shells with a very significant time delay AFTER impact, so maximum penetration into the armor has already occured. And, finally, even if I am wrong about every thing else above, I am a submariner, and let me tell you that modern periscope technology, even though it is only a fancy telescope and a bunch of mirrors, is probably WAY more expensive than you think it is.
-- killjoy57us, Feb 28 2007


// the inner vehicle may not be positioned exactly centrally within the low-density armour bubble.//

If it were off-centre by about 3-5 miles, that would confuse the enemy.
-- MaxwellBuchanan, Feb 28 2007


Great idea for a military out-house. Have it Skyscraper sized and offset... poor terrorists don't stand a chance
-- xxobot, Nov 15 2007



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