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Collimatrix

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Everything posted by Collimatrix

  1. Collimatrix

    AFV Engines

    This slide explains that opposed piston diesels have a small inherent efficiency advantage due to lower surface area/volume ratio.
  2. Collimatrix

    Bash the Pak-Fa thread

    You can see that the SU-57 with the UCAV flash on the vertical stabilizer also has replaced the upper and lower DIRCM turrets with antenna fairings. The obvious guess is that those antenna fairings are for controlling UCAVs.
  3. Collimatrix

    T-80 Megathread: Astronomical speed and price!

    If there was, I haven't been able to find it. @Monochromelody mentions what sound like one-off T-80 variants with neutral steer capability in this thread. Mysteriously vanished SH user @Levi posted this excellent guide to Soviet MBT transmission design here. Sadly, most of the important material has fallen prey to the dreaded link rot. But I remember the basics well enough. In short, the T-64, T-72 and T-80 have basically the same transmission. The parts aren't compatible between the three (that would just be silly!), but they all work basically the same way. In a typical Western MBT the power flowing from the engine is split into a steering drive and the transmission. The transmission varies the drive ratio, and the steering drive alters the balance between the left and right tracks as needed. The power is then re-combined and sent to the final drives. In the Soviet tanks the power is split into left and right half transmissions. Essentially, each track has its own transmission, and these transmissions also double as steering drives and final drives. It's very simple and compact, and making a Western-style system that could fit in the same footprint would be quite a trick. Not necessarily impossible, but quite a trick.
  4. The beautiful new Trump thread is filled with Frank Zappa hating troglodytes.
  5. Collimatrix

    General news thread

    Haven't these people seen Zoolander?
  6. Collimatrix

    T-80 Megathread: Astronomical speed and price!

    I don't think so. A poster here a long time ago mentioned that the Kharkov factory was working on an upgraded transmission for the T-80UD/T-84/Oplot family that would have a continuously variable drive ratio as well as neutral steering, but that this was never actually mass-produced.
  7. I wonder if Trump will start ratcheting up the amount he wants for the wall, or other high-pressure sales tactics.
  8. It occurred to me, while reading LoooSeR's account of how a bunch of peasants are clobbering the expensive Saudi military, that perhaps it was time to take a good, hard look at the Kingdom of Saudi Arabia. What a vibrant and wonderful country! Saudi Arabia leads the world in incest: Saudi Clerics have novel theories of science. They have a diversified, modern economy, which is definitely not unstable: Including a booming agricultural sector! What a swell place, with enlightened views on women!
  9. So, I'm snowbound in a little motel in Rawlins, WY. It's a dinky, creaky old place with no internet, no running water, and it's built on an old Indian burial ground. Anyway, I was thinking about music. I listened to The Pierce's Thirteen Tales of Love and Revenge on the way down here, end to end. Holy crap, this is a superb album. Allison and Catherine Pierce are both excellent singers with some really excellent harmonies (but not so often it gets dull). Instrumentation and melodies are varied too, but not so much it feels thrown together. And wow, the lyrics. The probity of the album's concept is immaculate. It oozes jealousy, loss, lust and toxic sexuality worthy of an opera. A taste:
  10. I've been meditating a lot lately on humans that I hate. I would say "people I hate," but once I take to hating a someone enough I de-classify them as a person. I've been focusing on hate more because I've realized that there is no point in marinating in negative emotions. What I had mistaken for righteous indignation was really jealousy. I'm not angry at the fraudulent because I hate fraud; I'm angry because they're talentless hacks and I could do a far better job. But I'm lazy, so you, my talented reader, you must do a better job, and become a more ravenous, vicious, and unstoppable leech than ever these mediocre reprobates could dream. I got the idea when I was reading the latest drivel from our favorite poly sci majors, and I realized that the authors are fundamentally parasitic con artists, and, more to the point, half-assed ones. The article is only worth reading if you want to heckle it. It has no factual content. The funniest part is probably where they're talking up the threat of firearms made on 3D printers, and then bring up the Ghost Gunner, which isn't a 3D printer. It's a fucking mill. You know, an example of that old-fashioned subtractive manufacture that's supposed to be obsolete now. This is as intellectually honest as hyping the threat of being stung to death by zebras in the streets, and pointing out that tapirs will bite your fucking arm off as evidence of the severity of the threat. I am, of course, heartened to see that these worms have doubled down on their claim that 3D printing is somehow applicable to clandestine manufacture of nuclear weapons, and are, as before, aggressively misunderstanding fundamental facts about isotope enrichment. If there's anything that these scum are good at, it's ignoring basic fucking nuclear physics. But other than that, it's not a particularly slick attempt to sew panic and profit thereby. The best possible result from this sort of scaremongering is that some useless government regulatory agency will be set up to strangle 3D printing with useless regulations. This useless agency will have some number of jobs that will be filled with poly sci majors and other unemployable refuse. Anyone employed in this hypothetical useless agency would work nine to five in a cubicle, watching whatever their favorite deviant sort of porn is, calling in sick about a third of the time, and occasionally writing internal correspondence that will be beautifully devoid of meaning. Is this sort of soul-raping mediocrity anyone's idea of a big steal? Because if getting a fake job at a fake agency to police a fake threat is your notion of making it, please enclose yourself in a running incinerator. You have some sort of pathogen that causes you to aspire to being a moderate nuisance, and that sort of plague needs to stop now. The problem with these people is that their lies are small. As we all know, big lies are better than little ones. Don't stretch the truth; snap it right the fuck off. The only thing standing between you and gigantic yachts made of cocaine is a sentimental attachment to the truth. The lord of this world will only reward you fully if you embrace him fully. Highly successful liars don't embroider the truth, they dispense with it entirely. Consummate your marriage to darkness and falsity, and receive glorious rewards. Don't say that the Eisenhower administration should have been more aggressive in defense spending and research. Say that the Soviets have more bombers and more missiles. You'll get to be president of Camelot, fuck Marilyn Monroe and will be spared the indignity of old age. Don't say that 3D printing could change the way nuclear weapons are made in the future. Claim that the Iranians and North Koreans, and hell, that the South Africans all made their nuclear weapons by using 3D printers. When asked for evidence of your nonsense, point to the South African invasion of Sudan. Say so with absolute arrogance and an unshakable air of moral superiority. If you are loud and persistent enough, and lie outrageously enough, Satan will come through. Don't shill for big coal companies by claiming that coal gasification technology will improve atmospheric conditions. That's only stretching the truth. You've got to go all the way, and just burn regular coal that you painted with Elmer's glue. Your enemies will end up under review, and you'll get millions in tax credits. Satan delivers. Praise Satan. But you have to be willing to go all the way with Satan. Satan despises spineless, cowering wretches who sin a little to get ahead but still consider themselves fundamentally decent people. Satan came through for the solar roadways bastards. Satan came through for Leroy Jenkins. Trust in Satan, and you will excel. Don't you trust Satan? Do you think that Satan is ignorant of your duplicity? You cannot serve two masters. Drink deep or taste not.
  11. Collimatrix

    Dealing with declassified/classified/secret data

    Don't post anything on this forum that will get it shut down by goons in suits. Don't post anything on this forum that might get your countrymen killed. If you screw up and accidentally post something that is uncomfortably close to any of the two categories I just listed, PM a moderator and they will disappear it like Stalin. Other than that, go nuts. If the super-secret specifications of some exotic armor array get leaked or accidentally photographed elsewhere and flood the 'net? It doesn't make sense to pretend that shit is secret.
  12. This concrete cross in the middle of the Arizona desert is mute testimony to the American spirit of can-do and getting things done, even if it's hard. In the 1950s, the United States had taken upon itself the essential task of spying on the Soviet Union. Why the hell they wanted to spy on a bunch of miserable commies waiting around in bread lines is beyond me, but the point of this story is that Americans can do anything they set their mind to, regardless of whether it's a good idea. To this end the US contracted Lockheed to design the elegant U-2 spyplane. This worked for a while, but eventually the damn commies developed a habit of shooting these things down. Clearly, the commies weren't going to make it easy to spy on them. The solution was to put the commie-spying-on camera on a platform that was both unmanned and in space. To this end, the Corona satellite family was developed: There was just one problem; while the astrogation systems (star trackers that could keep the satellite pointed at Earth), calibration systems (the big concrete crosses the satellites could focus on), and launch systems were all mature, digital communications had not yet been refined to the point where the satellites could beam over the images as a series of radio signals. Film images from the satellites were printed on physical film. The solution? Shoot the film canisters out of the satellite and catch them mid-fall with a cargo plane. Seriously: These two films describe the process in more detail: Eventually, high-bandwidth radio communications would be developed which would obviate the need for the mid-air snatch operation. This was significantly less awesome, but also much more practical.
  13. Explosive reactive armor is that brick-looking stuff that the Soviets loved covering their tanks in during the last days of the Cold War: Kharkov Stronk! I admit not knowing much about ERA, but a quick check around various sources has impressed the following things on me: -ERA is, pound for pound, the most effective armor technology that exists. Nothing else even comes remotely close. First-generation Israeli Blazer ERA was estimated to have a mass efficiency (vs RHA) of 20-24 vs HEAT threats. That's insane. The very best modern steel laminates using ultra-high hardness alloys magically welded to high toughness alloys achieve a mass efficiency of 1.5. MEs of 3 are spoken of in hushed whispers for exotic material composite arrays. ERA must be mounted on something fairly stout, on account of the whole "explosive" thing, but even mounted to RHA, the ME of the entire array is on the order of 2.5-3.8, and better still for ERA mounted on top of something more sophisticated. ERA is stupidly cheap and stupidly light for how effective it is. -The most commonly available descriptions of how the Kontakt-5 "heavy" ERA works are probably wrong. Surprise surprise; commonly available articles about a technical subject are completely wrong. Robb Mcleod's article gives a more likely explanation on the basis of areal density vs. installation mass and coverage. Instead of an extremely heavy one-piece flyer plate that snaps the APFSDS penetrators, Kontakt-5 works by having two flyer plates that move in different directions; one slightly up and one slightly down, guillotining off the front portion of long-rod APFSDS penetrators.
  14. Alright, we've got documents threads in aerospace and tanks, we need some for small arms now too. Small arms technology lags other fields by decades, by here at Sturgeon's House, it only lags by months! General Design Theory Treatises: First up is a link to George M Chinn's The Machine Gun. This is the premier English-language book on automatic weapon design theory. Also, because it was a US Government publication, it is legally available for free. The book is mainly focused on the design of autocannons, but the theory is applicable to smaller systems as well. If you read this book and understand it, you are ahead of 90% of the people in the industry. Next is this US Army document on small arms design hosted at Forgotten Weapons. The theoretical information in this is largely taken from Chinn, but it adds a lot of notes from experience on what does and does not work. It also has an excellent quantitative discussion of recoil, and some notes on various concepts the US Army was playing with at the time. More Specific Documents: Extractor Lift in the AR-15 series. This interesting series of tests disproves the rationale behind "improved" "lobstertail" AR-15 extractors. In addition, it shows just how much residual blowback pressure there is in the M4 (it's more than you'd think). Why Telescoped Ammunition Sucks. It really sucks. Jim Schatz on caseless ammunition. Very interesting read from a guy who was there when it happened.
  15. Collimatrix

    GLORIOUS T-14 ARMATA PICTURES.

    Perforated armor does not work particularly well against APFSDS in general. Doesn't matter what country the factory is located in. Perforated armor works by having an array of holes (thus the name) that are sized such that it is statistically likely that an incoming KE threat will catch one of the holes on the very edge. This tends to mangle the KE threat and also yaw the penetrator so it hit slightly side-on. APFSDS darts have a very high aspect ratio and a relatively small diameter, so they should be fairly easy to mangle and they should be enormously degraded if they rotate even slightly, right? So far so good. But APFSDS has a number of properties that also make it less vulnerable to perforated armor. The biggest problem is that APFSDS is really, really fast. If you impart a given amount of torque on an incoming projectile with a perforated stand-off plate, it will yaw less by the time it reaches the main plate if it's going faster. A given amount of torque will impart a given angular velocity on a given penetrator, and with APFSDS the penetrators are moving so fast that they don't have much time to yaw before they strike the main plate. On top of that, APFSDS has an extremely high moment of inertia about the yaw axes because it is so long. A given torque applied to the rod will rotate it less. Finally, APFSDS operates within a semi hydrodynamic regime, and the penetrators erode by design. They're not like traditional, full-caliber AP rounds that live and die by penetrator integrity, and this makes it a lot harder to apply torques to them in the first place. So, APFSDS is moving too fast to get turnt in time, it's resistant to getting turnt, and it's not easy to turnt it in the first place. All my sources on the matter (e.g. Hazell 2016) say that armor arrays that try to yaw APFSDS don't work particularly well. That said, a perforated array would work much better if the perforated array has more inertia. So, a perforated array made out of, say, depleted uranium might work against APFSDS where steel would fail. I have suspected in the past that this might be what the "DU mesh" in the Abrams' turret is, but @SH_MM has stated that he thinks a DU-based NERA array is more likely. In any case, the design of the DU arrays in the armor have changed from model to model. The T-14 almost certainly has ERA built in, and there is no reason to expect that future Russian ERA will look like 1980s vintage K1 "postage stamps". The grain size will only go down so much from a single rolling operation. To get ideal grain sizes, the process needs to be rinsed and repeated a few times. That costs.
  16. Collimatrix

    GLORIOUS T-14 ARMATA PICTURES.

    Everything I've read suggests that perforated armor does not work terribly well against APFSDS. I buy the rest of what you say, more or less. There have been substantial improvements to armor steel metallurgy over the past several decades. But they are costly improvements.
  17. You could have a conventional cartridge case that has perforations it bursts along.
  18. Complete speculation on my part. However, a hi-lo gun does not necessarily need the expansion chamber to be located in each casing, that's just how 40mm does it. It's entirely possible to have an oversize firing chamber.
  19. This is surprising. What could the Israelis possibly get from Ukrainian radar technology that they can't already make better on their own?
  20. I suspect that most cannons that are advertised as "low pressure" are actually high-low systems.
  21. The lower the pressure in the breech of the cannon, the less steel you need to keep the cannon from exploding. Low-pressure guns are much lighter, but also lower-performing relative to their size.
  22. Collimatrix

    Tank Layout

    Walter dug up these diagrams, I know not where from: Very interesting, and you can see how much space the Soviet trick of turning the engine sideways saves.
  23. Collimatrix

    WoT v WT effort-thread

    I bet a game where you raced Kettenkrads would be fun as shit. Those things look like they would be really janky and unstable while turning at speed.
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