Just a Weird Question to Throw Out

[pmulcahy11b]

If you had the technology to manufacture enough carbon nanotubes or buckyballs, how much weight could you save on an M1 Abrams or Challenger if you replaced the steel armor with it?

[Targan]

The volume to mass ratio of carbon is roughly one quarter that of steel (different grades of steel have slightly different volume to weight ratios), so that'e the simple answer if the same volume of carbon nanotube armor is required to provide the same protection as steel armor.

I know that carbon nanotubes have a far greater tensile strength than steel but I don't know anything about it's strength in other applications. I suspect if very long bucky tubes are interwoven to create plates like carbon fibre is used for it is probably much tougher than steel, even moreso if the molecular bonds are occurring between the fibres of the layers.

I think carbon insulates against heat much better than steel as well. And it won't form the same sort of molten shrapnel or spall like steel does when it's hit by a shaped charge or a hypervelocity, highly dense penetrator.

[cavtroop]

Im WAY over my head in this discussion, but bucky tubes look awesome. Is there any possible use of them in personal body armor, too? Imagine the weight savings there for a foot grunt?

[pmulcahy11b]

Originally Posted by cavtroop

Im WAY over my head in this discussion, but bucky tubes look awesome. Is there any possible use of them in personal body armor, too? Imagine the weight savings there for a foot grunt?

I've heard of speculation for the future that entire military or police uniforms could actually be made of woven carbon nanotubes. Wear that, plus an even tougher vest of thicker carbon nanotube fibers, and you could get a rather unstoppable trooper. I do wonder how hot such a uniform would be to wear, however; I don't know if carbon nanotubes would make very breathable fabric.

Another thing I've heard is on the horizon for the future is body armor made of artificial spider silk -- that would be a lot tougher than Kevlar.

[pmulcahy11b]

I know probably no one can give a definitive answer to this one because its classified, but IIRC there are tankers on this board who might be able to estimate an answer: what percentage of an M1's weight is the steel part of its armor? And what other parts of an M1 might possibly be candidates for replacement by carbon nanotubes or bucky balls in this hypothetical scenario?

And I wonder: would carbon nanotube or buckyball fabric make a good antispalling liner?

[raketenjagdpanzer]

Is the Abrams' armor "replaceable" though? Don't you get into a "Ship of Theseus" issue there?

[Tegyrius]

Back to Paul's original question...

Originally Posted by pmulcahy11b

If you had the technology to manufacture enough carbon nanotubes or buckyballs, how much weight could you save on an M1 Abrams or Challenger if you replaced the steel armor with it?

... what would the theoretical weight reduction do to the main gun's recoil effects on the vehicle (and its systems and crew)?

- C.

[Legbreaker]

Hmm, that's a good question. I'm thinking you'd have to modify the suspension and recoil systems to compensate for the reduced mass.
Or just use a completely diferent weapon with low to no recoil.

[Sith]

You can't really replace a tank's armor per say as they don't have a frame or chassis. The armor is the hull and turret, and everything else is just built on to those. The only way you could theoretically retrofit an Abrams with carbon nanotubes is to crack open the areas in the hull and turret that contain the ceramic pieces, then remove and replace them. An expensive process to say the least, and depending on where you cut, you could create weak points in the armor where it has become stressed. In total your weight reduction would not be that great as no steel would be replaced, although the armor protection would potentially be greatly increased.

For the sake of argument though, if you could craft an entire hull and turret out of carbon nanotubes you would probably get an eighteen (+ or -) ton vehicle with MBT level protection (assuming Targan's 1/4 rule). A 120mm cannon, however, can be placed on a twenty or so ton vehicle and work. A more practical weight though is around 35 tons.

I don't know about replacing other parts with carbon nanotubes as those are "working" parts. I don't know enough about this material to know how "wear and abuse" impacts it.

[pmulcahy11b]

Originally Posted by Tegyrius

Back to Paul's original question...



... what would the theoretical weight reduction do to the main gun's recoil effects on the vehicle (and its systems and crew)?

- C.

I suppose the best person to address that would be a former Sheridan crewmember.

[ArmySGT.]

Originally Posted by pmulcahy11b

I suppose the best person to address that would be a former Sheridan crewmember.

Check with the VA for all Sheridan Operators (or the 82nd Abn assn) whom have had a wrist rebuilt.

[Targan]

Originally Posted by Tegyrius

Back to Paul's original question... what would the theoretical weight reduction do to the main gun's recoil effects on the vehicle (and its systems and crew)?

Well, the M60-2000 weighs about 5 tonnes less than an M1A2 and seems to have little trouble firing the 120mm smoothbore. Five tonnes isn't much of a weight difference on a percentage basis though. I guess if an M1A2 weighed 1/3 less it migh have some problems. Still, maybe not. It's a very broad, low platform, inherently stable.

[Legbreaker]

With the mass it's likely to still have, I can't see there'd be too many problems a redesign/upgrade of the recoil systems couldn't deal with.