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Collimatrix

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Everything posted by Collimatrix

  1. Collimatrix
    The stresses will also be a function of road wheel diameter. For a given obstacle size, the horizontal vector of force of striking an obstacle will be smaller if the road wheel is larger, up until the obstacle is as high as the axle of the road wheel.
  2. Collimatrix
    The_Chieftain mentioned that the US did tests with an M26 with the swing arms reversed, and it didn't work very well. I suspect that leading swing arms need to be a bit stronger because most metals are stronger in tension than they are in compression.
  3. Collimatrix
    Tungsten is harder, but DU is self-sharpening (adiabatic sheer of the penetrator during erosion). DU is cheaper, but probably only in the USA. The USA has fuckloads of uranium-bearing ores, and fuckloads of spare uranium enrichment capacity. On top of that, the US barely uses fast-neutron breeder reactors, and produces power exclusively with a once-through fuel cycle (THANKS JIMMY CARTER) so that DU isn't particularly useful to the nuclear industry. The result? A bunch of 238UF6 sitting around in stainless steel storage tanks while engineers puzzle away coming up with a use for the stuff. So they end up using it as ballast in airplanes, weights for oil-drilling equipment, armor inserts in abramses, and AP material. I don't know if any other country in the world is in that sort of weird situation. DU is probably also a bitch to machine thanks to the pyrophoricity. You've got to be really careful with machined shavings of a material that bursts into flame spontaneously when it has enough surface area.
  4. Collimatrix
    More of 277 and its torsion bars. It looks to be using IS-7 style bars-in-tube torsion bars. The front idler appears to be attached to the first road wheel, similar to the arrangement in a lot of American tanks, and the first torsion bar appears to be longer.
  5. Collimatrix
    Now it is time to spread the gospel of Frank Zappa: Zappa's band was so unbelievably tight. It's amazing they kept up as well as they did. The white zone is for loading and unloading only.
  6. Collimatrix
    Priory, I highly recommend Paul Kriwaczek's In Search of Zarathustra if the subject interests you. Today I read Project Rho's page on Casaba-Howitzer. Nuclear shaped charges are my new favorite thing.
  7. Collimatrix
    The pressure increase shouldn't adversely affect the springs. That's a problem for the locking surfaces to deal with... and that unsupported chamber. The pressure increase amounts to a 14% or so increase in pressure, but because it's bottlenecked, there's a 20% or so reduction in thrust area, so the peak recoil force should actually be lower. That's different than bolt thrust, which is obviously higher.
  8. Collimatrix
    I doubt the Secret Service will indulge in anything like that. In my estimation, the US President just isn't that important. A gedankenexperiment; name a single Obama Administration policy. ACA doesn't count; the Obama Administration didn't come up with it. It's substantially Romneycare with a facelift, and even Romney didn't come up with that. Mitt Romney is of above-average intelligence for an Americans (most politicians are, although with some amusing exceptions), but he lacks the specialized training and knowledge of the healthcare system to come up with meaningful attempts to reform it. In fact, the same applies for American legislation generally. Barney Frank and Chris Dodd had nothing to do with their eponymous banking reform act, aside from the largely ceremonial act of introducing it to largely ceremonial debate and voting. Elected politicians simply do not know enough about the subjects they legislate upon to write meaningful regulations. When a politician actually does try to write a new law, it's obvious because it's a mess. Lawyers will look at it and go "WTF is this self-contradictory, redundant nonsense?" This is why the vast majority of legislation, and the overwhelming majority of legislation that actually matters is written by lobbyists and civil servants. Politicians are so ignorant of the highly-complex subjects they seek to grandstand on that any new rules they write about them fail to rise to the level of bad policy; it's just incoherent babble. This is why it's a mistake to anthropomorphize politicians. Don't think of them as people, think of them as imminently replaceable cogs in a machine. If you're rich and powerful enough to play the game, politicians are tools to be used and then discarded when they develop delusions of personhood. But don't think of them as people.
  9. Collimatrix
    When I started my quest to improve my education on nuclear energy, I was shocked to learn that neutron collisions are governed by essentially Newtonian physics. Unless the neutron is absorbed, a neutron collision is essentially a 100% elastic collision with the nucleus. Momentum is of course conserved, and kinetic energy is also conserved. Therefore, a collision with a hydrogen nucleus will split the kinetic energy about equally between the neutron and the proton, since they have close to the same mass. A collision with a uranium nucleus will remove very little kinetic energy from the neutron, since the nucleus is 230-something times heavier. Kirk Sorensen has a good discussion of moderator materials on his blog, further proving that he really does know what he's talking about. His presentations on LFTRs are just hideously dumbed down for his bovine audiences. Hmmm... So, today I learned that you should not put liquid dish soap into dishwashers unless it is specifically formulated for them.
  10. Collimatrix
    It is time for my favorite lesbian folk acoustic western swing duo:
  11. Collimatrix
    Ob 277. Note that the fourth road wheel uses a leading swing arm so that the turret basket is not sitting on top of the torsion bar. It's a similar arrangement to the AMX-30. I have been unable to locate good enough pictures to tell if the example in Kubinka is like this too. A lot of profile drawings show 277 with normal, all-trailing swing arms.
  12. Collimatrix
    According to these people it's pretty straightforward: http://www.handgunforum.net/glock/31350-g31-22-interchangability.html This is really a question for Ulric though.
  13. Collimatrix
    That would give you the best swept volume, yes, and there would be less bore surface area for a given amount of swept volume, so your thermal leakage would probably be less severe as well. However, there are several practical difficulties. There's a relationship I don't entirely understand between the velocity, distance between the bullet's center of pressure and center of mass and rifling twist rate that needs to be within a certain range to achieve good accuracy. If you start shooting sabots through existing barrels that were designed for a different load, it won't work that well. Obviously, it works well enough in tanks so you'd think with some finagling you could scale it down and get it to work OK. It could be that nobody has put the effort in yet. The obscenely hard to find Collector's Grade book on the SPIW documents some of the problems with sabots and small arms. They're probably soluble, but they're non-trivial.
  14. Collimatrix
    M829A3 has an EFC of 2, so over a total life of 1,500 EFC that comes to 750 rounds. So 200 shots for something with completely nutso pressure isn't that bad. Per Tanknet, M829A1 was 4 EFC, so you were down to 300-some shots with that stuff.
  15. Collimatrix
    Indeed. The Northrop team is clearly sitting on a bunch of classified numbers about the YF-23, but do they know those corresponding figures for the YF-22? In any case, the YF-23 was not a bad design at all. It would be the crown jewel of any other nation. Here in the USA though, we have so much goddamned money that we can do everything in duplicate, and only in that context does the Black Widow II come in second best. The two videos above aren't so much talking up the YF-23, but talking about fighter design generally. Nobody wants to hear about how the ATF program was screwed up and the USAF made the wrong choice, but we can't give you specifics because it's all still classified. That would be boring and provide no useful information. Hearing these guy's thoughts and experiences on fighter design is worthwhile, because they were clearly champs at that (if narrowly second best). It's interesting to hear Bob Sandusky describe area ruling and stealth shaping in such a way that they sound potentially synergistic. Again; guy knows what he's talking about. He worked on YF-17 as well:
  16. Collimatrix
    This is from a documentary on the YF-23. I may have to pick it up, it sounds interesting. While I remain provisionally convinced that the Lockheed bird was better, the Northrop design team members were no dummies, and anything they have to say about fighter design is well worth listening to. On birdstrike testing: Apparently birdstrike requirements are a major mass driver in fighter canopy design!
  17. Collimatrix
    So this is another instance of the Carnot Equation. Higher peak pressure means a higher difference between peak and exhaust temperatures, which means greater maximum possible efficiency.
  18. Collimatrix
    I think this will end up like PAK-FA. There were tons of studies and a handful of prototypes for new fighter aircraft in the late Soviet era, but PAK-FA was not a rehash of any of them. People thought it would be based on 1.44, 7.01 or Berkut, but it was a novel design. Internet speculation on its appearance was generally wrong. A likely shopping list of features of Armata looks like this IMO: -New 125mm gun that is backwards-compatible with existing ammunition stocks, but can use unitary ammunition with longer penetrators. You probably can't get such a weapon to the same class as the Rheinmetall 120mm; there just isn't enough case volume to work with, but you could go a long way in bridging the gap, especially if the pressure ceiling were higher. -Urban combat-oriented features like the JSDF Type 10. Lots of cameras for driver and commander, remote weapons stations of some sort, thermal optics to highlight ATGM kill teams (how many times have you seen combat footage from Syrian and thought "man, those RPG tank-killer teams would be totally screwed if those T-72s had been refitted with thermals?"), short overall hull length, high-precision neutral steer, etc. -Hydropneumatic suspension. The Soviets have been playing with it since the 1950s, and now that the Russians aren't doing ginormous 10K production runs, they can splurge a bit on bling. -Modular armor ala Merk IV seems to be the way to go. For very little extra cost, you reserve the ability to up-armor your tank very easily in the future. -Getting rid of the the frontal weak points around the driver's hatch and gun mantlet. They've been trying to do this since Object 187, and Russian milbloggers love to harp on similar weakpoints on the abrams. -Probably no turbine, alas. Russian gas turbines still aren't as good as American or Western European models. SFC and power density are comparable to their American counterparts and sometimes a little better, but TBO is still much, much worse. A diesel should be fine, especially a fancy new common-rail fuel injector type. -Auxiliary autocannon seems likely. -I wouldn't rule out a driver-in-turret configuration. The Soviets did more research on this arrangement than anyone else.
  19. Collimatrix
    My favorite aria is the immortal Habanera from Bizet's Carmen. Der Hölle Rache kocht in meinem Herzen from Die Zauberflöte is a close second. This is one of the all-time best earworms ever written. A lot of people can get this song stuck in their head and they don't even know what it's called. But, if they are in Spain, why are they singing in French?
  20. Collimatrix
    Could you get the same effect by moving to a faster-burning powder?
  21. Collimatrix
    There's some interesting discussion of the actuation of the grid fins here.
  22. Collimatrix
  23. Collimatrix
    I don't really like musicals unless they have cannibalism or cross-dressing in them (ideally both). I only know of four shows that meet those criteria:
  24. Collimatrix
    What I find a little hard to understand is how there came to be a separate military culture in the USA so quickly, since Saint Nixon abolished the draft so recently. There definitely is a separate military culture. I have cousins and uncles in the military and consider myself fairly quick at picking up on the nuances and minutia of different cultures, and even then I don't always get the jokes on Duffelblog.
  25. Collimatrix
    How does allele dominance work? This is something I've wondered ever since I was introduced to Mendelian inheritance that I assumed would be explained later, but never was.
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