31–40 of 89 posts
The part about shielding radiation sounds dubious to me. I thought shielding from radiation was mostly about mass. How is that foam supposed to shield better than cast metal of the same weight? Maybe the "foam" deteriorates less?
Neat, though of course this raises the question: what would it take to engineer a foam-piercing bullet?
What if you shoot twice at the same spot?
Would this be effective against micrometeoroids and orbital debris?
"Let me start by saying that it is not a crazy idea and is actually what I have been working on recently. I even have a proposal in DARPA on testing the performance of the material at supersonic speeds. At this time, our data covers up to a speed close to 1Km/s as you mentioned. We have not tested the performance at higher speed and that is what I was hoping to conduct soon."
(I asked if it could be used for space debris at 8-15km/s, and apologized for asking a crazy question)
What if you shoot twice at the same spot?
If you can reliably hit a target that small, you could just shoot the other fellow in the eye and not worry about armor.
To hit someone in the eye, you've got to aim at their eye and land a round there. That is, accuracy at hitting a pre-specified target.
To hit armour in the same location twice, you need either two (or more rounds) delivered consistently on whatever happens to be where the first round lands. It's a case where being a Texas Sharpshooter actually works (painting bullseyes around the bullet holes you just shot into a barn).
A compound impactor with a leading and secondary round might work, for example. Difficult to package into a small-arms round, but possible. Keeping everything on the same impact point would be the crucial element.
The part about shielding radiation sounds dubious to me. I thought shielding from radiation was mostly about mass. How is that foam supposed to shield better than cast metal of the same weight? Maybe the "foam" deteriorates less?
The composite metal foam that was comparable to lead utilized steel with higher concentrations of tungsten and vanadium.
Are there any potential downsides to this stuff? It seems too good to be true.
It's going to be expensive, may not meaningfully improve survival in actual combat situations, and may not actually be successfully deployed. How could this be extraordinarily effective at stopping bullets but not meaningfully improve survival? Fairly few American soldiers are killed by gunfire which directly strikes them; even fewer of these soldiers are killed by gunfire which directly strikes them on their armor.…
And a big ass gun /
Neat, though of course this raises the question: what would it take to engineer a foam-piercing bullet?
I'm not an expert, but after some Googling, I think the bullet they're using there consists of a steel core inside a lead envelope inside a copper or copper-nickel jacket. So, at a guess, you'd want to replace the steel with something much harder and/or denser. Tungsten, maybe? I dunno. Depleted uranium would probably do it; I've never heard of it being used in anti-personnel rounds, but in cannon sizes it pokes hole…
The part about shielding radiation sounds dubious to me. I thought shielding from radiation was mostly about mass. How is that foam supposed to shield better than cast metal of the same weight? Maybe the "foam" deteriorates less?
> The metal foam is made of 2mm-diameter hollow steel spheres in a stainless steel matrix (created using powder metallurgy).