We had radar proximity fuses in use in AAA rounds during W.W. II, and they of course used vacuum tube technology. One of the members of our local ham radio club worked on that project in the ’40s. One of the challenges for his team was developing tubes that could withstand the 10s of thousands of Gs at launch. Ouch.
Now we have this, via an e-mail from my nephew. I find it fascinating, funny, and a little disturbing all at the same time. Ordinary rifles spin a bullet at 2K RPM? They missed that one by an order of magnitude or two. A rifle chambered for the 5.56 NATO round for example rotates the bullet at around 300,000 RPM, more or less depending on barrel length, rifling twist and bullet weight. But as I often say; what’s an order of magnitude (or two) between friends?
It is very telling, if not entirely predictable, how they smear the general public in the article– government = good, whereas regular citizens = dangerous or at least troubling. They of course have it entirely upside down and backwards in that department.
I saw that this morning however it appears in this case it was a smooth bore if I read it correctly.
Rotational speed would be an interesting stress problem but pales in comparison to the shock problem, at least to me anyway. I know first hand how hard it is to shock harden something just for “light weight” shock. The forces involved in propelling a bullet is down right scary.
I do know they were working on GPS guided artillery for a while too. Again the impulse is so large it rips most electronics to shreds. The upshot is with the advancement of solid state electronics if you can find a potting material that is both rigid enough to support and elastic enough to properly displace the energy it’s a relatively simple problem… Once you’ve found the material that is.
Actually I believe the article (and patent) got it right. They are quoting revolutions per second, not per minute.
The other issue is that it is diffacult to make a battery that won’t flat-line when firing / launching. Even at the relatively low mortar shell velocities it was only recently that they got batteries good enough for the “mortar-shell cam” that could be launched up and parachute down sending back real-time video. There were shortly replaced by micro RD drones just recently. Not sure how they did it during WWII – interesting question.
A couple years ago someone asked a bunch of questions about this sort of thing over at “snipersparadise.com” like he was a complete newb at long range shooting.
The guys basically told him to pound sand. Snipers are proud of being “10 cent killers” and even with a range of 1.24 miles as noted in the article linked we are still in conventional small arms territory, at least for 338 Lapua, 408 Cheytac, and 50 BMG (among others).
However, the Excalibur GPS guided munition is a reality for 155mm artillery pieces, so the problem is just one of making things smaller. Although this seems to be laser guided instead of GPS guided, but that is an even simpler technology, the same as the old “Copperhead” 155mm artillery shells. We got rid of those because they “see too much” sometimes, and if you turned on the targeting laser too soon you could have a round land on the spotting team. I wonder if they’ll run into the same problem here?
Heh. “Upside down and backwards.” Did you know that the symbol for negation in Egytian hieroglyphics was the image of a man, upside down and backwards? I have used that locution myself, a time or two.
Heh. “Upside down and backwards.” Did you know that the symbol for negation in Egytian hieroglyphics was the image of a man, upside down and backwards? I have used that locution myself, a time or two.
Regarding accelleration of projectiles – when I was working with the engineers on the original Copperhead project, we had to test components to the equivalent of 20,000g acceleration. Nobody had done anything like that before so one of the engineers rigged up a pendulum-hammer thingy that would strike the component under test with the equivalent of 20Kg’s.
It was fun building the proto-type. Watched a lot of ferro-magnetic material get turned into powder, heh, heh, heh.
This does seem like an awful lot of technology to do what you can already do with a high quality rifle and an experienced sniper. I know I’ve heard of snipers hitting their targets at much greater ranges.
I’ve long wondered if a lot of the military technology we have is an attempt for the government to consolidate power. It sounds like a conspiracy theory, but does make sense. Instead of training our soldiers to become expert marksmen, we give them the most basic training and then send them off with automatic rifles and lots of ammo. If a time ever came where the government was fighting its own people, rather than have millions of vets who are expert marksmen to contend with, we have millions of vets who are used to fighting with equipment they cannot legally own. Rather than train snipers who can make kill shots out beyond 1 mile, we develop technology that can do that with an average shooter and then restrict that technology to government use only.
Example in round numbers: Suppose a bullet leaving the at 2500 feet per second. Twist of 1 in 8″. For each foot, the bullet makes 1 1/2 rotations, so the the rate is 3750 revolutions per second or 225,000 rpm.