All Is Grist 2

Piensas al azar.
  • Turns out I was wrong, here, when I corrected the grammar in that line in Snow Falling on Cedars. Every other criticism of that flabbergasting douchebaggery stands—like that aware means "pathos" not "beauty"—but apparently the grammar itself was not incorrect, just a bizarre idiom that I was not acquainted with till I came across mention of the Japanese book-listing SF ga yomitai! on Mike Flynn's blog.

    Normally the "ga" particle means nominative, but in some instances, apparently, it's used to mean a passive (without using the passive verb conjugation). I suppose it's kind of like how "se habla español" literally means "Spanish speaks itself" rather than, what it means idiomatically, "Spanish is spoken" or "one speaks Spanish".
  • I know I've mentioned that the zled for "damn" is "drown it in hell", and their image (not doctrine) of hell is an infinite water-filled void you sink through forever. This was for two reasons. One, of course, was just that I wanted an alternative to the usual fiery or frozen hells of human cultures. The other was an interesting fact I came across.

    Do you remember in the Disney Peter Pan when Captain Hook is threatening Tiger Lily with drowning, and says "There is no path through water to the Happy Hunting Ground"? That was a real Ojibwa belief (so is Peter losing the shadow, at the beginning—J. M. Barrie seems to have got hisself a book from somewheres).

    What's really weird is, it was also a Náhuatl belief—Tlaloc had to construct an afterlife for those who died by water, they were barred entry to Mictlan. I think something similar shows up in a bunch of other New World cultures, as well; it's kinda a thing, here, that drowning is "a fate worse than (dry) death".
  • When people, rightly objecting to political correctness, say that calling people from East Asia "Asians" rather than "Orientals" is silly, because "Asian" covers everywhere from the Middle East to Kamchatka, they actually embarrass themselves, and play into the hands of the PCniks.

    Because quick, what is the point furthest east that the "Orient Express" traveled to? Oh. Right. Istanbul. What state does the phrase "oriental despotism" originally refer to? Oh. Right. Ottoman Turkey. Remember, when the German Empire complained in World War I that the Allies, by allying with Russia, were binding themselves to a "semi-oriental" power, what was Chesterton's comeback? Oh. Right. That by allying with Ottoman Turkey, Germany was binding itself to a power entirely oriental.

    The fact, kiddies, is that "oriental" and "Asian" are entirely co-terminous terms. "Oriental" just sounds old-fashioned, which is the only reason I say "Asian" instead (well, and a slight preference for avoiding unnecessary fights with idiots).
  • There's an anime this season, Charlotte, that's...well, for about eight episodes, it's pretty good. Then it decides to turn into a wan "Days of Future Past" knockoff, only with even stupider decision-making. At least they're on the run from organizations that want to use their powers, rather than the "bigotry" of people worried about guys who can topple buildings with their minds.

    Nevertheless, very disappointing; it develops all these characters and then ignores two-thirds of them almost completely for the last third of the series. What is it about the concept of people with superpowers that makes it so hard to get stories that involve that topic right? You could at least knock off something other than an X-Men arc that'd recently been made into a major movie.
  • It'seemed hard to be sure, because I can't get that good of a look, but I think that the Minority Report series may be continuing the movie's tradition of cutting-edge production design. Specifically, I think the soldiers here and there in the crowd scenes have a version of digi-camo that's based on a hexagons, not squares.

    Yeah, I know, "hexagons are high-tech" is arguably overplayed, but it's that way for a reason. Namely, it looks freaking awesome. Besides, it could well be that the hexagons are dictated not just by Rule of Cool, but could be diagetic—there could be a structure built into the uniform, perhaps making it a cloth armor, that has hexagonal cells.

    Should we be worried that this show's on Fox? I know I said "with robots" but it really could be that they hate good science fiction, period (which, again, has nothing to do with Firefly).
  • According to "Recoil Considerations for Railguns" by Eric L. Kathe, recoil force is an order of magnitude lower than the "ballistic loads", which I think means your recoil energy is one-tenth your muzzle energy (as a rule of thumb). Which presumably means that the 1% c, 4-gram projectile (muzzle energy of 4.3 tonnes TNT) only has the recoil force of 430 kilos of TNT, which a soft recoil system reduces to 215 kilos. Still not something you really want hitting the front of your ship every time it fires its gun, though, especially not at 4,000 rounds per minute, so, still gonna go with topological inertial protections.

    It occurs to me they might want to upgrade the muzzle velocity, since the zled ships themselves move at 1% c. Maybe 2% c? That brings the muzzle energy to (22=)4 × 4.3=17.18 tonnes TNT. That means you've got 1.72 tonnes TNT recoil force, only reducible to 859 kilos with a soft-recoil system, so the topological inertial protection is even more necessary. It also makes you as well-equipped to fight zled ships as someone shooting at F-35s with a Vulcan. A muzzle velocity twice the speed of your typical target is probably pretty typical for weapons in aerospace applications (although then again, the Goalkeeper CIWS does shoot rounds that are only 30 m/s faster than the missiles it shoots down).
  • You can express firing-rates in Hertz. For instance, the M61 Vulcan, with a fire-rate of 6,000-6,600 rounds per minute, fires at a frequency of 100-110 Hertz. 110 Hertz is the key of A2. The GAU-8 Avenger has a fire-rate of 4,200 rounds per minute, which is 70 hertz—just slightly higher than C#2/D♭2, while the GAU-12 Equalizer can fire at the same rate as the GAU-8, or, in the GAU-"22/A" on the F-35, at 3,300 rounds per minute, which is 55 Hertz, A1.

    The Gryazev-Shipunov GSh-6-30 has a fire-rate of 4,000 to 6,000 RPM, which is 66 and two-thirds Hertz to 100 Hertz, just above C2 ("low C") and a bit above G2, respectively. The Gryazev-Shipunov GSh-6-23 has a crazy-town 9,000 to 10,000 rounds-per-minute fire-rate, 150 Hertz to 166 and two-thirds Hertz—so it fires halfway between D3 and D#3, or else a little above E3.

    So basically all aircraft autocannons are still pretty much playing bass—which is interesting, because the guns themselves sound like buzzsaws (which might be the mechanism spinning the gun as distinct from just the firing).
  • John W. Campbell apparently said, and encouraged his writers to remember, that "an alien thinks as well as a human, but not like a human". Only, one, most aliens don't, actually; the only ones I can think of who actually think as well as humans but not like humans are Cherryh's kif and atevi, and both of them are probably unrealistic (because the kif probably wouldn't become sapient and the atevi seem to often find things troublesome that are actually easily explained—given that "society" is treating unrelated conspecifics as kin, in the first place, "you guys are like my kin though we share no blood" is not something that anyone who has a society should find terribly difficult). Races like Kzinti are actually stupider than humans; many if not most aliens have blind-spots no human society ever had. And every attempt at a "really alien" alien is usually less like a character than it is like a prop (a distinction I get from John Wright).

    And the second point is, who told Campbell there was more than one way to think? I am at least passingly familiar with four Native American/American Indian philosophies and five Old World ones, they are not actually any different from each other—nothing in Navajo thought is not found in China or the pre-Socratics, the Sioux are Platonic hyperrealists, the Nahuatls and Hopi are almost down-the-line Chinese philosophers. Existentialism, Buddhism, Chinese thought, Aristotle, and Plato are all recognizably talking about the same things, albeit coming to different conclusions on some of the questions. Why it's almost like philosophy deals with an external reality and therefore only certain interpretations of it are actually tenable! Besides, remember, Campbell was one of the rubes who fell for Sapir-Whorf. The fact is that nobody that humans can talk with at all is going to think that differently from a human; and the only people humans can't talk with at all, are probably not remotely the same kind of thing humans are. Sure, maybe energy beings are difficult for humans to talk to (if they even talk), but another animal that evolved from some other rock's pond-scum? Give us some time, we'll figure it out.

    Honestly the biggest barrier might be needing some way to simulate their vocal apparatus, if their language even uses sounds—but sign-language is not fundamentally a different thing from spoken language. If the alien communicates with flashing bioluminescence, you're still going to have patterns of flashing lights you can classify as "nouns" and "verbs" (though a lot of the nouns might be verbs morphologically, and all of the adjectives might be).


Sierra Foxtrot 7

Pensées sur l'SF. 553 is 7 × 79, and the sum of nine consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79).
  • Realized I had had space-combats take place at the top speeds of spaceships, which...malarkey. At 7.5% c, which is what my humans' starships do, you cross one light-second in 13 and one-third seconds. At the speed of zled starships, 12% c, it's only 8 and one-third. That's not a lot of time to fight, and if your enemy manages to hit you with a few 100-gram rounds, each will hit like a 6-kiloton W54 tactical nuke.

    So I decided that ships only speed up to their top speed when they're making the dozens-of-AUs trip to safe space-fold distance, and the first thing they do when they fold into a system is decelerate to "tactical" speed. That makes parasite craft make much more sense, especially for the humans; the motherships can save their propellant for carting their parasites around, and leave the combat maneuvering to the parasites. The parasites, likewise, are usually launched via catapult, and mostly use their engines for high-G maneuvering (decided their crews are in tanks of acceleration gel, since they're too small for a full-blown topological inertial-compensation system; the one attached to their autocannon only has to counter one force in one direction, the recoil, and thus can be smaller).

    "Tactical speed", thus, is about .6% c, for humans, and about 1% c for zledo. (Though zled ships, with metric-patching engines, don't fly by expelling a propellant, they don't have an unlimited budget for their flight, either. It takes more power to impart more velocity, so the maximum speeds their engines are capable of are only a bit better than those of human ships; it's the maneuverability/acceleration that's superior.)
  • I was worried that maybe the rebreather I used as a model for the air-recycler on the VAJRA suits was too heavy. SCUBA air-tanks, see, are often weighted, so that they don't force you to float when you'd rather dive (remember, they're full of air). But I looked up rebreathers for mining, firefighting, and mountaineering, and nope, 15 kilos seems to be pretty normal. One firefighting unit was 12.8 kilos, but I doubt it lasts as long as the 15-kilo ones.
  • So a bunch of people say you wouldn't use mechanical counterpressure suits, because they're skintight and therefore look unflattering. One, they're not actually all that skintight (on the outside); MIT's BioSuit is not even as form-fitting as a wetsuit, and people of less than optimal body-configurations do things requiring wetsuits. It's about like a motocross jumpsuit.

    Besides, even if it were true, nobody says you can't wear something over your spacesuit. On Mars for example you'd probably want a fairly heavy cloak—think Jawa cosplay—since Martian dust can get blowing pretty fast—and is also toxic and magnetic and pretty much something from one of those murder-worlds evil Galactic Emperors put prisons on.

    Other places you'd probably have a relatively light protective cover, as an extra defense against punctures (which are no longer deadly but "frostbitten hickey" still hurts).
  • In the 1988 comedy/shotacon movie "Big", at one point, the child-transformed-into-Tom Hanks is shown a toy idea, a building that turns into a robot. His response? "I don't get it. It turns from a building into a robot, right? Well, what's fun about that?"

    What indeed.
  • I didn't mention this at the time, but I think the demise of Almost Human proves that Fox is biased against good science fiction, as the Browncoats claim—as long as that good science fiction has robots in it. (Obviously a bias against good science fiction has nothing to do with Firefly one way or another.)

    Maybe it'll take a third show (Sara Connor Chronicles was the other) to prove the point, but I don't know what it is with them. Maybe there are just budgetary issues? Sarah Connor was probably relatively expensive, and Almost Human was the first sci-fi show in quite some time that didn't look exactly like every other show on TV.
  • Speaking of good sci-fi shows, the Minority Report series shows no little promise. The only real complaint I have is it's a little too insistent with the "See? It's the future! Our future! See? Damn you, see?!" I expect it'll settle down after the first few episodes, though.
  • So it occurs to me that the appropriate term for flying animals of an alien biosphere is not "fliers", but "fowl". The word, cognate with German Vogel, derives from the same root as "fly" and "flight" (there's probably some metathesis involved in the difference between "fgl" and "flg", Germanic languages are into metathesis).

    Likewise "fish" is an appropriate term for the endoskeleton-equipped swimmers; it's not monophyletic on Earth, either, and both its synonyms, "pisces" and "ichthyes", are "a typological, but not a phylogenetic classification". (Incidentally, whales are too fish—specifically Sarcopterygii. Of course, so are giraffes and ocelots and Presbyterian ministers.)
  • An aspect of my setting, with implications for my "future history" that I can't be bothered to flesh out (or rather am content to leave implicit), is that in the 24th century, every ethnicity is referred to by its continent of origin, as Asians are now. I.e., blacks and whites are called Africans and Europeans (yes, even if they're from America). Non-white, non-black Hispanics, and Native Americans, are both referred to as American.

    "Asian" on its own usually, in my setting, means East and Southeast Asians, not people from Central or South Asia (because I'm not British). I think Central and South Asian are called either "Central Asian" and "South Asian", or possibly Middle Easterners and Sub-continentals (leaning toward the former, since it's concise). Also I'm pretty sure North Africans are called "North Africans", although none have come up.

    Yes, that system glosses over mixed-race people. So does ours, but this system has the advantage of not referring to people, many of whom are lighter-skinned than most Navajos, as "black".


Protect Yourself, Or Deal Some Damage

Skyrim line, smiths say it. Good title for a post about weapons and armor.
  • Really got down to brass tacks about my armor. At times it felt like I was crawling over the brass tacks. But now I know pretty much exactly what my armor is made from, both human and zled. The zled armor is a boron-nitride nanotube suit under plates of a metamaterial that, though little more massive than silica, can shift its structure in nanoseconds to meet an attack with the (local) density of osmium and the melting-point of tungsten. In between there's a suit of auxetic foam, like we're currently experimenting with for blast-curtains and EOD suits. Decided zled irregular troops don't wear STF armor, they just wear the auxetic-foam/BN nanotube armor without the metamaterial plates. (One benefit the BN gives is radiation-shielding, especially vs. neutrons.)

    The humans' STF armor is actually nanotube-reinforced polymer textile (somewhat like Kevlar, but not Kevlar—I went with a different kind of polymer, because some of the properties I needed to know don't exist for aramids e.g. they don't melt, they sublimate/disintegrate), soaked in a polyethylene glycol gel with silica in it. As I said, PK special-forces wear only a "union suit" made of the stuff, while the heavier armor also features a cuirass and some limb-plates made of stiffer panels of the same material. The VAJRA powered armor is two-layer, the inner being ferrofluid—nano-scale magnetite powder suspended in PDMS (siloxane)—governed by sensors much like the ones in magnetorheological brakes, but much faster, single-digits of microseconds rather than milliseconds. The outer layer is boron carbide sandwiched with good old-fashioned homogeneous steel; the whole thing, minus power-plant, environment-system, and power-lifting system (i.e. just the armor itself) weighs about 18.5 kilos.
  • While I was torturing myself doing this, I came across a way for the zledo to tune their lasers: one of the things you can do with optical metamaterials is tunable filters. One paper I found involved a filter tunable over a range of 3,650 nanometers, although it started at near-infrared and went into mid-infrared, whereas what I need is near-infrared to near-UV—but that's a range only 770 nanometers across, so once one has the tech to tune to UV at all, in principle tuning to near-IR is relatively simple.
  • Other things I came across doing this? Nanocellulose, which is extracted from cyanobacteria or wood pulp, and is clear, stronger than Kevlar, and electrically conductive. They're thinking of using it in organic LED displays that can be rolled up, certain window applications, and it can also be used as, e.g., food thickener, because it's still just "dietary fiber". Its one weakness? Still cellulose, and not very dense, therefore it soaks up moisture—even from air—and puffs up. At the very least, serious waterproofing is required.

    I think the humans make windows and maybe display-screens out of aluminum oxynitride...which is also known as "transparent aluminum". You can get better performance from 4.1 centimeters of AlON than from 9.4 centimeters of bulletproof glass—the AlON will stop .50 BMG at that thickness (presumably only from a certain distance), glass won't—so it'd obviously be a popular choice for e.g. VIP vehicles.

    A substance that I think zledo and possibly also humans put as a coating on weapons to let them cut through practically anything, is n-tert-butoxycarbonyl-protected diphenylalanine, or BOC-protected diphenylalanine to its friends. It's apparently as strong as Kevlar and can only be scratched by diamond—and in itself it's clear (but pH dependent, apparently, so you probably don't want to make your whole weapon out of it—"got to periodically re-apply the coating" vs. "the whole blade dissolved").
  • It occurs to me that, if you're going to use Raufoss-style HEIAP rounds in your coil vulcan, while only firing at the muzzle velocity of modern .50 BMG, then why not use .50 BMG and leave the coil part at home?

    So now the coil vulcans still shoot .50 BMG Raufoss-type HEIAP rounds, but shoot them at a muzzle velocity of 1,578.445 meters per second—giving them the same muzzle-energy as 20 millimeter, before the HEIAP is factored in, i.e. basically giving the same performance as 20 millimeter HEIAP rounds from a 13-millimeter package.

    Assuming it scales linearly, that muzzle-velocity means power-requirement per shot of 53,867.5675 joules, which, with silicon-air batteries, means that 1,000 shots uses a silicon-air battery massing only 1.052 kilograms.
  • To calculate the total weight of a VAJRA suit, we add in the weight of the power-assist exosuit and an air-recycler. The Warrior Web weighs about 9 kilograms, so we'll say the VAJRA version—which will let you flip, though not throw, a car—is the same. The lightest scuba rebreathers I can find weigh 15 kilos; while what a VAJRA suit has is not just a rebreather but a true air-recycler, that's a good figure for the weight we're talking about.

    That, of course, brings the total mass of the suit to 42.5 kilos, the weight of a twelve-and-a-half-year-old. The exosuit, of course, cancels that out, and the weight also makes it a lot easier to, e.g., stand up to the recoil of your "muzzle energy (therefore recoil) of a 20-millimeter" coil-vulcan. It also makes it slightly harder for a zled to just fling you like a rag-doll, though not enough harder that it actually prevents it ("All right, we'll goad this guy into tossing us like unwanted toys. After eight or nine of us, he'll be too tired to keep fighting!")
  • This article on coilguns and railguns says, about using them for anti-missile CIWSs, quote:
    If incoming round interception can be accomplished with good reliability, it will make armored vehicles as obsolete as knights on horseback.
    Can you count the errors in that sentence? I see at least two. One is, "good reliability" is not the same thing as "100% reliability". We've had missile-interceptor CIWSs on ships for decades, we still armor them.

    The second is, knights in armor weren't rendered obsolete because of something that shot down bullets; they were rendered obsolete because bullets became good enough that wearing enough armor to stop them became prohibitively heavy. Taking the risk of not having armor rather than have to slog around 50 pounds of steel, was the option they went with; there was no alternative to armor (except "run for cover more quickly than armor permits") that did it.

    Besides, what if your enemy decides that, indeed, anti-tank missiles aren't worth the effort, because of your electromagnetic CIWS...and then he shoots your vehicle with a laser, or with an EM gun much like the one your CIWS uses (e.g., a 30 mm coil version of the A-10's GAU-8 Avenger, which is also used on the Goalkeeper CIWS)? Boom (literally)—bet you wish you'd had some armor on that slag-heap that used to be a vehicle.
  • I realize, of course, that recoil force ("felt recoil", anyway) is a fraction of actual muzzle-energy, but, on a spaceship at least, it isn't all that different. Recoil on a planet goes down into the ground through the shooter's body, or through the mounting of a mounted gun, but recoil on a spaceship has nowhere to go. (The same is also true of airplanes; certain large autocannons—the Gsh-6-30 on the MiG-27, notably—need special mountings, and still cause unpleasant noise and vibrations, the latter of which can even damage fuel tanks, avionics, and landing lights.)

    Another factor is that rail- and coilguns are quite likely to have more recoil forces than firearms, since their "ejecta" consist of a bullet and a negligible mass of plasma, whereas a firearm is ejecting all the gases produced by burning its propellant, along with the bullet. You can put vents on the top or sides of a firearm's muzzle to let some of the ejecta escape at a different angle; that's not possible on an electromagnetic gun. (Maybe some kind of counterweight piston like in the AEK-971, self-contained—maybe connected directly to the bullet's motion down the barrel—rather than using propellant gases?)
  • Recall, please, that the reasonable distance for space-combat is one light-second, which is just a bit under 300,000 kilometers. How to design a space missile? Let's start by giving it a dry mass equal to the launch-mass of the biggest air-to-air missile ever, the Soviet K-100 series, since those 750 kilograms are going to be necessary to hold our 600-kilo magnetic-confinement fusion rocket. Then give it a mass-ratio equal to that of the AMRAAM (19:11, given its Isp of 254 seconds and cruise speed of Mach 4—I don't think that's a national-security issue).

    That mass-ratio, coupled with MC fusion's 8,000,000 meters per second exhaust velocity, results in a delta-v of approximately 1.5% (1.4678%) the speed of light. That can cross a light-second in 68.13 seconds, or 4,400.37 kilometers in one second flat. A direct hit of an entirely-empty missile, at that speed, hits with the force of a 1.74 megaton nuke; since the most space available for the warhead is 136 kilos (if it scales like the KS-172), the actual explosive (not counting the kinetic kill—you don't make space-missiles dependent on direct hits), and the maximum achievable in a nuke is 6 megatons per megagram, the explosive yield of such a missile is 816 kilotons, around the yield of Soviet RT-2PM Topol ICBMs.


Be Cool, Be Cool

A laser calculator I find online (I think some of its assumptions are simplified) says that the waste heat of a 10 MJ laser is 882.353 watts, assuming 85% efficiency (50% is considered the max for the near future—currently we top out at around 12%—but the 24th century isn't quite "near" future, and the zledo are 300 years more advanced than we are). I find an efficiency for micro-channel heat-exchangers of 1.5 kW/cm2 (presumably per second); at .882 kilowatts, that means almost exactly 1.7 shots per square centimeter.

A zled laser's power mainsprings can supply it with power for 48 shots. One face of the hexagonal prism casing on a zled laser is 4.053 centimeters wide; suppose we put a band of micro-channel heat-exchangers around the laser (toward the end), but not covering the bottom face or the bottom half of the two faces touching the bottom. If we do that, we basically have 3 whole faces and 2 half-faces to work with, giving us (3+(2×(1/2)=)4, for a total width of the heat-exchanger of (4×4.053=)16.212 centimeters. That, right out of the gate, means that merely by being one centimeter wide, we can exchange the waste-heat of (4.053×4×1.7=)27.56 shots. Make it an eighth of a bãgh—"aliens don't use nice round numbers of Earth units"—or 1.60875 centimeters, and it's got the ability to dump the heat of 44.34 shots, meaning that, if that cooling-efficiency is per-second, it can dump the heat of firing its entire charge, in one and one-elevenths seconds.

The hand laser has a waste-heat of a bit over 282 watts; assuming the same kind of heat-exchanger, that comes to 5 and 5/16ths shots per square centimeter. The faces of the hand laser's hexagonal casing are a little over half the width of those of the long laser (not exactly half because though the lens has half the diameter, its casing is the same thickness), 2.533 centimeters. The hand laser's springs power it for sixteen shots; a band a centimeter wide can dump 17.23 shots. Make it a twelfth of a bãgh, or 8.58 millimeters, and it can dump 14.78 shots' worth of heat in one second, and the whole spring in just over 1.08 seconds.

Incidentally, my old calculations for laser power-supplies forgot the fact that lasers are inefficient; I just went by the power of the beams themselves. What 85% efficient actually means is that for every twenty joules you pour into the laser, you get seventeen joules out as laser (and what our current best, 12%, means, is that for every twenty-five joules you put in, you get three joules of laser—we're not looking at laser weapons except on nuclear ships for a long, long time). So I guess that, assuming the .1 megajoule/kilogram minimum for polymer molecular springs, powering the 3.2 kilojoule hand laser for 16 shots would require a 602 gram power supply, while powering the 10 kilojoule long laser for 48 shots would take one weighing 5.6 kilos. Fortunately, polymer molecular springs have a theoretical maximum of ten megajoules (their range is apparently two orders of magnitude wide); merely going up to the "1 megajoule/kilo" kind gives us a lighter spring than the one the hand laser uses. Except it probably weighs a bit more, the extra weight being reinforcement (you really, really don't want a spring under that kind of tension breaking on you).

Note: I messed up the calculations, earlier, for the width of the hexagon. It's better now. I think I was also doing something wrong on the calculations for the hand laser's heat exchangers.


De Colores

So, I'm making a change: now zled lasers are "frequency agile". What this means is, for close-in work you set them to near-infrared, for medium range you set them to visible light, and for long range (or anti-materiel—or shooting through two people at once—at close range) you set them to near-UV. I discovered that switching from near-infrared to visible light (specifically c. 500 nanometers, which is at the green end of blue-green) doubles the range at which a 10 kilojoule "long" laser will do the damage I need it to do, in a scene in my book (sniping troop-transport choppers, specifically by lasing holes in their tilt-rotors). Switching from that to 250-nanometer near-UV doubles the range again, to the point where it can vaporize 10.5 centimeters of aluminum (I figure a good proxy for any other aerospace material) at a whole kilometer. Go down to 210 nanometers (you want to stay above 200 nanometers or you're not talking "near UV" any more, and a planetary atmosphere becomes opaque) and you can vaporize 10.5 centimeters of aluminum at 1,190 meters.

I don't think I need to have them be very scary, "gets its laser from ionizing radiation" free-electron lasers—which it's also kinda hard, if not actually impossible, to make man-portable. I've found several papers online about other ways to do frequency-agility in lasers; I'm not sure they demonstrate the ability to tune the laser all the way from 250 to 1000 nanometers, but zledo invented the space-fold drive the year we landed on the moon, Earth's 2015 tech is not exactly indicative of what they can do in the 24th century. I imagine there's a fire-selector on the laser, somewhat like the one that switches an assault rifle between full-auto, burst, semi-auto, and safe (actually many assault rifles only have burst or full auto, e.g. the M16A2 only has burst, while the AK often if not usually only has full-auto). I imagine the typical troops get a series of pre-sets to switch between—near-IR, one or maybe two near-UVs, at least one visible wavelength—while the sniper-types might have a more fine-tunable device.

The main reason one changes one's laser's wavelength is for range, so there might be a "ideal range for" indicator next to the wavelength-selector. Then again perhaps not, since a lot depends on e.g. whether one is fighting armored or unarmored opponents, and how armored, or whether one is doing anti-vehicle stuff.

Interestingly apparently near-infrared is more likely to blind you than visible, since the whole eye is transparent to those wavelengths; it's not that big a concern, though, since even 24th-century humanity has medicine that can regrow those cells, and the zledo are 300 years more advanced. Still I imagine most military personnel wear protective contact lenses, and they might be a part of civilians' "survival kits" for if shit hits fans before they can evacuate. Not sure if zledo do things like put in contacts with their fingertips or with the backs of their extended claws—maybe they stick the lens to their fingertip and open their eye with the back of their claw, that's somewhat like how humans put in contacts. I imagine having a whole third-eyelid nictitating membrane (also called a "haw" on horses at least) makes the whole thing a bit more difficult.


All Is Grist

Thoughts. 'S really almost a SF-thoughts post, but a lot of it, indirectly.
  • Found out I was wrong, that sound TV's Frank makes does have an IPA letter. I was just looking in the wrong place. It's not a click, it's an implosive: the voiced velar implosive, written [ɠ].

    The way one writes that sound Frank makes, then, is [jʌɠwiː]. "Cuckoo kids out for cuckoo kicks. [jʌɠwiː]!"

    (This IPA is so much more fun than the other kind, though admittedly it's not hard to be more enjoyable than a beer so over-hopped you'd be forgiven for thinking you got hold of a toxic chemical equipped with a safety-bitterant by mistake.)
  • Decided one of the zled languages uses a click in some places where the other two members of its group have a stop—the dental click, the sound Americans spell "tsk" and Brits spell "tut" (and God only knows about Australians, Canadians, or South Africans; my guess is Aussies and Afrikaners write "tut" but Canada is a 50-50 chance of either).

    That zled language uses it to replace the alveolar stop (t) in certain words; I haven't worked out the entire rule but since it's so far only shown up as the first letter of two proper names, one of a supporting character and one of a mythological figure, I figure I'm okay. Not sure if I should change some of their other sounds too, like maybe make some of their Ds into a voiced velar implosive (I can't hear the difference between voiced and unvoiced clicks, not having been raised speaking isiZulu).

    I discover that human languages don't like to end syllables or words on clicks; the Khoisan languages only put them at the beginning of root-words, while Hadza, Sandawe, and the Bantu languages with clicks can also put them at the start of syllables within words. Some of my alien languages, however, end syllables on clicks; fundamentally it's not much weirder than you people ending words with aspirated voiceless stops (my dialect of American English doesn't "release" those stops at the ends of words—"bock", "bot", and "bop" are hard for speakers of other dialects to tell apart, when we say them).
  • Re-doing my pistol round. The bullet is still 9 millimeters diameter, 16 millimeters long, but I realized that .357 SIG is weak—its resemblance to .357 magnum is greatly exaggerated. Decided to go with actual .357 magnum. 1 gram, even, of nitrocellulose will move a 12-gram bullet at 430 m/s (giving a muzzle energy of about 1.1 kilojoules). It'd take 420 milligrams of octanitrocubane to achieve the same thing, which has a volume of 203.883 cubic millimeters.

    Going with the 10.77 casing diameter of .357 SIG means the "casing" is 13.4 millimeters long, and goes 12.1 millimeters up up the side (so only a quarter of the bullet sticks out past the top—a lot of these caseless rounds are practically telescoped). Thus, the round becomes 9×13 millimeter—two whole centimeters shorter than the CIP designation for .357 magnum. (Overall length is less than half that of .357 magnum, 17.35 millimeters as opposed to 40.)
  • Thought I'd go a bit into depth on my PK armor. Decided, the standard Peacekeeper armor is a sheer-thickening fluid undersuit, which might also contain the power-assist exosuit (not in the same systems, they'd interfere with each other), under a breastplate that's harder. Might also wear shoulder, elbow, and knee plates, but like now, those are optional. The helmets come with or without faceplates.

    Remember the Australian lady in the short story there on my DeviantArt? And how she says most special forces don't do heavy armor? The special forces guys—Peacekeeper Special Purpose Forces, to give them their full name—wear only the flexible undersuits, without the breastplate or any of the other rigid parts. Their helmets always have the faceplates. Due to their clothes being less bulky, I imagine they get referred to by other Peacekeepers as things like "longjohns" or "union suits".
  • In another entry under the heading "even Cracked knows that's stupid", we have the guy in Jurassic World who wants to weaponize raptors. See also the xenomorphs in Alien, and the idiotic plot of straw corporation Weyland-Yutani to weaponize those.

    Aside from what that article points out, about living things making lousy weapons—xenomorphs made a little sense, at least, for the Engineers, since they had no future plans for Earth—is the ugly hypocrisy and Freudian projection involved in this leftist trope. Go look up who made the closest thing to a doomsday weapon ever. It wasn't a corporation. It was two leftist darlings working in tandem: the government and academia, i.e. the War Department and a bunch of physicists.

    Incidentally, what's with this idea you sometimes see, that the Manhattan Project guys were dupes? Who, pray, in the US military, is supposed to have bamboozled Einstein and Oppenheimer into building a fission-bomb without their realizing it? How's that supposed to work? "Gasp! You monster! Those equations we keep having to explain in layman's terms for you—their implications! You knew all along—about this concept some of us personally created about half the theoretical underpinnings of!"
  • Partly for xenobiology purposes, partly for my own interest, I've been looking into the transition from lobe-finned fish to tetrapods. Some cool stuff. Apparently our spines being shaped the way they are, rather than like those of fish, is one of the features in question. Another one? That so many land animals taste like chicken, and not like fish, the "fishy" taste being something to do with substances produced by the death of aquatic animals' tissues.

    Of course the limbs are the big change. The fins of lobe-finned fish are kind of like horse forearms, just a stack of joints, up to a point, where they start dividing. You can identify one of the divisions as the precursor of the radius and ulna. The transition from the bunch of bones that makes up the fin, to tetrapod digits, is kinda vague; we can point to some bones toward the end that became the carpals and metacarpals, but how exactly the phalanges show up is sketchy.

    Oddly, lobe-finned fish have bones in their limbs that aren't connected to the rest of the skeleton. The two halves of the pelvic girdle were once just the ends of the "leg"; they fused to each other and to the spine I think some time during the fish-to-tetrapod transition. The shoulder, of course, is still only held on by the clavicle and muscles. I think some of the ancient lobe-finned fish (not coelacanths or lungfish) had ribs; those are fairly obviously modified vertebral processes.
  • The interesting thing about coilguns and railguns is that they don't seem to work differently from regular guns—not in some of the ways you might expect. Like, you might be surprised by railguns with muzzle flash and smoke almost indistinguishable from a firearm, but that's the plasma. I don't know if they make quite the same "cork popping" sound as guns, but if they have the precise same sonic boom, if they fire at supersonic velocity.

    Which reminds me, it's probably not accurate to say that lasers make a gunshot noise from the wound. They almost certainly do make a "pow" sound, but, not being contained and pressurized like a gun barrel, it's probably not as loud. Probably more like popping a potato in the microwave or a soda can in the freezer—which probably solves the "no suppressing a laser" problem , since that's about the sound-level a suppressed firearm does.


Shoot All Week

Another gun post. Title's a reference to the Henry repeater, "the damn Yankee rifle they load on Sunday and shoot all week." It's a pun: "repeat" and "firearms", i.e., another gun post.
  • Had occasion to get down to brass tacks about my coil vulcans. The man-portable, three-barrel ones fire relatively standard HEIAP ammunition with ferrous-metal "driving belts" (which some modern .50 caliber machinegun rounds seem to have), to give them 20-millimeter performance in a 13-millimeter package. The six-barrel ones mounted on aircraft are 30 millimeter, basically a magnetic version of the GAU-8 or GSh-6-30.

    Instead of "spinning up" electrically, like most American vulcans, or via gas, like the Soviet ones, I think 24th-century coil vulcans actually do it with their recoil—and given a 390-gram 30-millimeter round at 845 m/s has a muzzle energy of 139.235 kilojoules, the recoil is considerable. You might as well get some use out of it. (Yes, you can use recoil to spin part of a gun; the Mateba and Webley autorevolvers did it, along with cocking the hammer.)
  • The coil-vulcans mounted on battle-spacecraft ("starfighters") are only 5.56 millimeter, because they go at 1% c and mass only 4 grams, the same as M855 "ball" M16 bullets. The kinetic energy calculator says the muzzle energy for that is 4.3 megagrams of TNT.

    You can counter part of that with a soft recoil system, but that usually only halves the recoil energy, so you're still talking about slamming the vessel with just over two tonnes of TNT every time the thing fires. Maybe those ones spin up electrically, and the topological inertia protections keep the guns from tearing the ship apart.

    Ooh, I like that. The topological protection would cause huge "muzzle flare" for the people who use topological sensors. (Since they use metric-patching guns, their own weapons are equally detectable, if not more so.)
  • Brought back bayonets on zled lasers. Since my favorite weapons are halberds, thought I'd have their bayonet be heavy, for chopping as much as stabbing. The shape would be a bit like a skeggöx "beard" (some of which came to a point), upside-down and at a somewhat different angle.

    The bottom half of the hexagonal prism that forms the outside of zled lasers has an accessory rail set in it, something like the Smith & Wesson TRR8 . The bayonet attaches to the rail, rather than with a special lug or socket. They don't need a laser-pointer, because laser weapons can be used for their own, by using the same optics as the weapon does: the dot you're sighting with suddenly explodes. (You can also use the laser's optics for a scope; zled lasers have a little panel that pops up under the rear sight to show a reflex-image of the laser-optics picture.)

    Their long lasers are 117.7 centimeters long, of which 91.4 cm is the optical cavity. That's the equivalent of a human having a gun 97.7 centimeters long—and remember, they wear their lasers like swords. 97.7 centimeters is about seven centimeters shorter than the M1860 light cavalry saber.
  • Decided my zled anti-materiel laser does about 30 kilojoules; it's about five thirds as strong as the .50 BMG we use in our anti-materiel rifles, and about three-fifths as strong as the 20×110 millimeter round used in the strongest anti-materiel rifles currently in existence.

    The normal zled laser is 10 kilojoules, which is high for an infantry weapon but not unreasonably, for a society where all soldiers wear armor (also where they don't have to worry about recoil). I have the anti-materiel laser use the same power-cartridge as the normal ones; it just goes through them three times as fast.

    The anti-materiel ones are basically the same shape as the standard ones, but their lenses are wider, so they can focus at a longer range.
  • The laser equivalent of machinegun fire is continuous-beam; burst-fire is presumably a brief zap for a set period of time. Since for optical wavelengths you have to pulse the zaps, you can talk about the "burst" in terms of the number of pulses.

    Whether "burst" or full auto-fire, the main way you use it is to keep the enemy behind cover while your allies advance, just like machinegun fire. As anyone who's played Reach (at least on Legendary) will tell you, continuous beams are just as likely to make you keep your head down as a machinegun is.
  • I think I've pointed out that the oft-quoted "shots per enemy kills" numbers don't actually show anything about "reluctance to kill", they show use of suppressive fire. Besides, we don't actually have a way of tracking how many rounds have been fired; at least some of those "shots" stats actually use "rounds shipped over" (e.g. to Vietnam) as a proxy measure for "rounds fired"—never mind they're two quite different things.

    But apparently, one of the major studies often cited in support of the "reluctance to kill" interpretation, the famous one by Brig. Gen. S. L. A. Marshall, was, at best, deeply flawed...if not fake. Apparently Marshall didn't even actually ask the people he interviewed the questions he claimed to be answering—as in "how often did you fire?" or "how often did you actually shoot to hit the enemy rather than just at him?"

    Of course, none of that changes the fact artillery, not small-arms fire, is the main killer on battlefields. There was a reason Stalin called it the God of War. (Well, in premodern war, dysentery was the main killer, but the only people who'd name that "God of War" are Nurgle's Plague Marines.)
  • This paper (Google the title to find the article as a pdf) says it takes 6 megajoules to accelerate an 18-kilogram projectile to 420 m/s. Now, .50 BMG Raufoss, like the coil-vulcans basically shoot, has a muzzle velocity of over twice that—915 m/s—which comes out (if it scales linearly) to 13 and 1/14th megajoules. Of course, the projectile masses only 43 grams, not 18,000, which (agaim, assuming linear scaling) means a power-requirement of 31,226.1905 joules. That means to power the coil-vulcan for 1000 shots requires a silicon-air battery massing only 1.65 kilograms.

    Late addendum: The GSh-6-30 shoots 390-gram bullets at 845 m/s. That would mean that firing each shot takes 43,591.2698 joules, which, assuming 1,350 rounds (the maximum capacity of the A-10 Thunderbolt) requires a silicon-air battery of 1,148.75 grams. That's about the size of a motorcycle's battery.

    The aircraft autocannon's battery is smaller than the "1,000 shots at 31 kilojoules" battery because I did the first one backwards, and divided the battery's energy density by the power requirement instead of the power-requirement by the energy density. The correct battery size for the 13-millimeter coil vulcan would be 609.55 grams, the same as a lithium-ion battery used for power-tools nowadays.
  • Zled uniforms are armored; they can block the "sidearm" hand lasers up to pretty close (within about thirty meters, typical "battle zero" for the Beretta M9; up to ten meters, they keep the wound smaller, reducing the bleeding), and at least are better than "exposed skin" against the long laser (so it's only lethal out to, say, half a kilometer instead of a whole one). The interesting thing is, the main way the uniform is armored is it's got a layer of energy-dissipating stuff sandwiched inside it, peeking out at the ruffles on the cuffs; the cuffs glow when the uniform has to dump a lot of energy.

    Zled powered armor isn't just powered in terms of lifting assistance (which, given it's designed for people who can lift several times their own weight, is really just "cancel out its own weight and that of any other equipment"). It's also made of "smart" material, adjusting its molecular structure to cope with any attack. The only way to get through is to hit it with too much to cope with at once; zled long lasers can do it by hitting from about 150 meters away, their hand lasers from about a sixth that. Humans do it with anti-materiel rifles or actual anti-tank grenades.
  • If the Serdyukov SPS is the future-y Makarov, what's the future-y version of the M1911 (America's service pistol for most of the Makarov's run)?

    My vote is the Detonics Defense MTX, an entry for the Modular Handgun System competition for picking the M9's replacement—which somehow manages to be a 10(+1)-round M1911 while still being .45 ACP.

    If one wanted a futuristic M9 (America's service pistol when it won), I would go with either the Px4 (P×4?) Storm, or possibly the 90two. Probably the first one, just to punish the 90two for its stupid name.


All I Survey IV

Random thoughts.
  • I made my AIs be in Prolog because Prolog is cool, and also because Prolog is a big deal in AI. I may have to specify, though, that they're actually in Prolog and JavaScript; Prolog is declarative-only, JavaScript is imperative.

    Why JavaScript, and not, say, Python? Python's not an ISO standard. JavaScript is. Why, then, not C#, which is very similar to JavaScript and is an ISO standard? There are a whole bunch of bridges between Prolog and JavaScript, many more than there are between Prolog and C#.

    I guess I'll be adding references to ISO 16262, then.
  • That thing I harp on about people putting things in their work that are dictated by "drama" rather than "what makes sense", has made it very difficult for me to watch movies and TV. For instance, one complaint I had about Dark Matter (really about the only one) was the part when the android (that's her name, "the android", they're going for a weird minimalist approach with the whole series and somehow it doesn't piss me off) goes out on the hull of the ship to fix something, and gets knocked out by the static on the hull. Um..."tether"? The barely-Iron Age ancient Hebrews knew about that one, they tied a string around the priest's leg before he went into the Holy of Holies on Yom Kippur, so if he was struck dead by the presence of God they could get his corpse out without violating the sanctum.

    Or, everything in Jurassic Park (the first one) that has to do with the Velociraptors. Aside from their naked skin and sideways hands and having voice-boxes, I mean. For instance, that redshirt guy who dies at the very beginning? Well, how the hell did that happen—except that they designed their pen incredibly badly? Leaving to one side that one raptor would not be strong enough to move the car-thing, we, um, kinda have a handle on moving big, dangerous animals so your staff don't get eviscerated. A Velociraptor—even if we're pretending that's a senior synonym of Deinonychus, and was noticeably smarter than a sparrow (which it wasn't)—is not more dangerous than a Bengal tiger. It's probably a lot less dangerous. We are talking about a cassowary here, basically, those aren't even as dangerous as peccaries, let alone Bengal tigers.
  • I found on the the intertubes that Kenshiro, the human-mimetic robot, uses (=is capable of outputting) five times the power its predecessor Kojiro could. And I find that the motors on Kojiro have 40 watts of output power, and there are about a hundred of them. Now, I don't know if that means 40 watts each or 40 watts total; I'll assume the former.

    That means Kojiro has a power requirement of 4 kilowatts—comparable to DARPA's Atlas—and therefore that Kenshiro has a requirement of 20. If true, that means over 200 times the energy requirements of an average human being (2000 kcal/24 hours=96.85 watts). That's also 78.57% more power than is used by TOPIO, but remember, Kenshiro also has (64/39=)64.1% more degrees of freedom than TOPIO (and 16/7 as many degrees as, =128.6% more degrees than, Atlas).

    Remember also that Kojiro and Kenshiro are barely even an "alpha"-build on human-mimetic robotics. Remember thirdly that with the average 72 kWh laptop battery, you can power a 20 kW system for 3 hours 36 minutes—and with 24% of its mass (the percent of the average human's mass that's fat) made up of polyvinyl-gel lithium-air battery (11.14 kWh/kg), you can power a 180 centimeter, 74-kilo version of Kenshiro for 9 hours 53 minutes 32.35 seconds.
  • Changing the way my human ships are named. I had gone with a Chinese-style system—"Type [Number]"—which is how they name e.g. missiles, and indeed also naval ship-classes, in China, but not how they name spaceships or aircraft. So at first I went with the same system as my guns: a two-letter abbreviation of the company name (e.g. GA for General Atomics), followed by a one-letter abbreviation for the type of ship (M for mothership, E for escort ship, P for patrol ship, etc.), then a number.

    But then I decided to change it to the actual Russian system for naming aircraft (my gun-naming is a modification of the Russian one), with a two-letter representation of the names of companies that are single words ("Ka-27", a helicopter from Kamov), before the number, and a three-letter one for companies with two-word names ("MiG-29", the fighter plane from Mikoyan-Gurevich). "KoE-382 mothership" has a nice ring.

    The number after the prefix is "years since 1945 that it was introduced", because they're Peacekeeper ships and the UN was founded in 1945. The aforementioned KoE-382 was introduced in 2327. (That's also where I get the numbers for the guns.)
  • Revising that classificatory scheme gave me an idea for the zledo: so now, instead of collating things by letter and number, they collate them by the periodic table. So, e.g, instead of "Variant C" or "Model 14", they say "Lithium Variant" or "Silicon Model". (Still think they add sub-versions numerically, but ordinally—"Oxygen Model, third variant" would be our "Model 8, version 3".)
  • I think that the idea of rugged individualism on the American frontier, which as I have pointed out has no reference to reality, may have been born of literary romanticism. No, I don't mean dime-novel Westerns, as much as those did distort the popular conception of the pioneer phenomenon.

    I mean the Transcendentalists, who, after all, were the big thing in American literary and intellectual life just before the pioneering enterprise really kicked into high gear. Sure, the fact is that nobody was really self-reliant out here, except some half-demented hermits; sure, the "pioneers" were people who jailed you for cussing and hanged you for stealing livestock. But the idea of getting away from society and its supposed corrupting influence, living a "self-reliant" life in a state of nature more unrealistically idealized than any two "Noble Savage" theorists, was a powerful influence on the popular conception of the frontier.

    Transcendentalism covers the period from about 1836 up into the 1870s or even 1880s, though it lost influence starting around 1850. That pretty much is the "frontier era". And they were huge; the American branch of Romanticism is almost inseparable from Transcendentalism.
  • Apparently it's hard to make lithium-air batteries rechargeable...and lithium reacts violently with water, kinda a big deal for robots that have to live in environments humans do. Not to worry, though, silicon-air batteries are, according to Wikipedia, more efficient, theoretically (they're just as hard to recharge but my thing's set in the 24th century, they've had time to work on it). The new number given for silicon-air (a new study, maybe?) is 14.23 kWh/kg; that lets a 74-kilo, 180-centimeter Kenshiro-clone that's 24% battery operate for 12 hours 38 minutes 10.46 seconds.

    I'm keeping the gel itself as a subcutaneous layer of polymer. It's subcutaneous not to supply all the body with power (most of the power is supplied by wiring), but to evenly distribute the "like a three-year-old" weight of the battery. It's also brightly colored (dyed), because it looks cool, but also because you want to be able to know when your robot has been punctured. I'd said it was polyvinyl, but that turns out to only mean PVC (polyvinyl chloride), and apparently the main polymers used in batteries are things like PAN (polyacrylonitrile). It has a number of properties to recommend it.

    They don't really need to cause the liquid PAN to solidify when exposed to air under conditions other than the oxidation of the silicon suspended in it—i.e. clotting, to keep them from bleeding to death—because my androids normally have a small amount of limited-lifespan nano-bot goo, for self-repair. In an emergency where the nano-bots weren't working fast enough, they could probably spray something on the wound to harden the "blood" around it.
  • My setting has something called "toothpaste", but it's actually mouthwash. Mouthwash with non-replicating nano-bots suspended in it, that activate when inside a mouth, and seek out and destroy plaque and germs. "Paste", you see, as distinct from "goo", is the term for non-replicating nano-bots.

    They also have programmable nano-bot hair-gel, because of course they do (it can also act as dye—dye that can be removed at a moment's notice). People wear shirts powered by their bioelectric fields that have slogans in light-emitting polymers; I think some people might wear programmable images and patterns on their clothes.

    Nobody has moving images on their shirts, though, because that would be freaking annoying. "I'm a walking animated Flash-ad"—that's not a sentence that would ever be spoken by a mouth with all its teeth.


Blast It

I should've realized that you can't necessarily fit all the explosive inside the grenade. 30 grams of ONC has a volume of 14,563.11 cubic millimeters, whereas the "based on shotgun slug" grenade-design I was using only has a volume of 5,282.41 cubic millimeters—the HEDP round would need to be 2.76 times the volume of the slug. The 20.71 grams of ONC for the air-burst one, meanwhile, has a volume of 10,053.4 cubic millimeters, a volume 1.9 times that of the slug.

All is not lost; a polymer-cased grenade is presumably much less dense than a slug. (I find, incidentally, that the slug in question, given its mass and volume, has roughly the density of thulium, 9.33 g/cm3. It's also the density of the molybdenum-alloy "mandrels" used for piercing stainless steel tubes, so, maybe they're made of that, for improved armor-piercing characteristics?) If we wanted to make the HEDP round work the same, it just has to be 62.83 millimeters long, or about as long as a modern 3" shotgun shell (remember, shotgun shells' actual length is about half an inch shorter than their listed length); the air-burst round has to be 43.25 millimeters long, or about as long as a 2.25" shell.

One thing this probably means is that, while they can load tubular magazines with any combination of shot, slugs, and grenades they feel like, they have to load box magazines with all the same thing. (Actually if the 1.75" Aguila "minishell" is any indication, they may have to load their tube-magazines with all one thing too, or else have some mechanism to vary the "size" of the motion in the feed mechanism. Apparently the minishells have feeding problems in many guns.)

Les armes à feu spéculatives 3

Thoughts on SFional guns.
  • Recently had occasion to design my setting's .50 BMG equivalent. .50 BMG is actually exactly 13 millimeters, I don't know where that "12.7×99mm NATO" business comes from. The bullets are typically a full 60 millimeters long. Now, to move a 49-gram bullet at 860 m/s requires 14.515 grams of nitrocellulose propellant, so it'd take 6.096 grams of octanitrocubane. 6.096 grams of ONC (density 2.06 g/cm3) has a volume of 2959.369 cubic millimeters.

    Going with the base-area of the .50 BMG, which has a case-diameter of 20.4 millimeters, resulted in a somewhat gawky final product (the propellant "casing" went less than halfway up the bullet). So instead we're gonna go with the shoulder diameter, 18.1 millimeters. Now we just say that the cylindrical volume of a cylinder of that base-area, height undefined, minus the volume of the bullet, equals the volume of the propellant. Then we add the volume of the bullet and propellant, divide by the case area, and get a height for the "casing" (actually the propellant) of 42.45 millimeters. The "casing" sticks out 2.55 millimeters around the bullet (and out from behind it), and goes 39.9 millimeters up the side.

    Hence, I guess, my Peacekeepers' sniper-round is "13×43". With an overall length of 62.55 millimeters, and a total cartridge-weight of 55.1 grams, it's a lot lighter than a round of .50 BMG, which weighs 116.8 grams. That means that your sniper can carry a lot more ammo—over twice as much. Currently, .50 BMG snipers usually carry 50-100 rounds, which weighs 5.84-11.68 kilos; 100 rounds of the caseless only weighs 5.51 kilos.
  • Apparently, I was wrong, octanitrocubane would not smell like camphor. It's in the same family of explosives as RDX and HMX; the former is what's in C4. Commercial C4 has "odorizing", "taggant" additives put in to make bombs made of the stuff harder to hide (I don't think the military bothers)—the main "taggant" in the US is apparently very noticeable to dogs, I don't know how noticeable humans find it. But apparently, on its own, it smells "bituminous", i.e. tarry. Personally I like that smell, like fresh asphalt, but I'm apparently in a minority on that one.

    Also, I must be more careful about specifying it's denatured octanitrocubane. ONC, see, is a high explosive; firearm propellants are low explosives—they deflagrate (burn) rather than detonating (kablooie). But, when Heckler and Koch were making the G11's caseless ammo, they (in order to solve "cooking off" issues) used a propellant consisting mostly of RDX, denatured so it would burn slowly enough to propel ammunition—and not explode in the user's hand. (The reason they went with RDX is it's harder to ignite than nitrocellulose is, hence it solved the "cooking off" problem caused by no longer having the ejection of spent casings for a heat-sink.)
  • Recalculating, I find I can, in fact, have my 12-gauge round be caseless. Went with twenty pellets of #3 buckshot, the same as was used in the M576 buckshot-grenade for the old M79 grenade launcher—which isn't really a grenade, it's literally a shotgun shell you shoot from a grenade launcher. But I decided to make the pellets out of the same tungsten alloy as those found in the QBS-09; taking their diameter of 5.3 millimeters and their mass of 1.4 grams, we get a density of 17.96 g/cm3, which makes #3 buckshot (diameter 6.4 millimeters) weigh 2.465 grams—twenty of them mass 49.3038 grams. I'll come back to that.

    Decided to make the propellant straight nitrocellulose, not denatured ONC, for this one: we want the propellant to take up room. The loading tables for a 49-gram load say it takes 2.0088 grams of powder; that, in nitrocellulose (density 1.40 g/cm3) has a volume of 1434.857 cubic millimeters. Now, the closest you can pack spheres still results in wasted space—the maximum efficiency of packing equal spheres is 74.048%. Twenty pellets of #3 buck has a volume of 2745.166 cubic millimeters; in effect, though, it has a volume of 3707.279 cubic millimeters, wasting 962.113 cubic millimeters. We just have to fill that in, though, with our propellant. The remaining 472.744 cubic millimeters? We divide that up among the twenty pellets, solve the resulting volume for its radius, and come up with a coating .17 millimeters thick. Interestingly, #3 buckshot with that coating exactly comes to the edge of a 20-millimeter diameter circle when you pack it hexagonally, as if this arrangement were fore-ordained.

    You stack your twenty pellets in one layer of seven, one layer of three, one layer of seven, one layer of three. I checked, it fits. This arrangement results in a round 24.29 millimeters long, and, again, 20 millimeters in diameter; the remaining volume around the pellets and propellant is presumably filled up by some kind of flammable filler—"liquid wadding"?—to make up the rest of the cylinder. (I envision it being a clear, resinous-looking substance, I'm not sure why except that it'd look awesome.)
  • Now, it turns out I miscalculated before, on the number of rounds a shotgun can hold; shotgun-shell lengths are apparently the length of the casing before being crimped down (or after firing), and are about half an inch longer than the actual length of the round. So 2.75" shells are really 2.25 inches long; a QBS-09's magazine is 28.575 centimeters long, the Benelli M4 and Remington 870's magazines are 40.005 centimeters, and the Mossberg 590's magazine is 45.72 centimeters. That means the QBS-09 can hold eleven rounds (nearly twelve—its 24th-century equivalent probably the full dozen) of our caseless 12-gauge round, the Benelli and Remington can hold sixteen, and the Mossberg can hold eighteen (nearly nineteen—the full nineteen, again assuming a generous future).
  • A shotgun slug with a weight of 49 grams isn't all that unusual, though that's kinda a big one (1.75 ounce). But it requires the same amount of nitrocellulose the buckshot does; with this one, we can go with ONC. I find a typical 12-gauge slug is about 17.65 millimeters in diameter and 21.59 millimeters long. That requires (2.0088/2.38=)843.696 milligrams of ONC, which has a volume of 409.561 cubic millimeters. Treating the slug as a cylinder, we find that the denatured-ONC propellant "casing" sticks out from it 1.175 millimeters, and goes 16.94 millimeters up the side of the slug. That brings its total length to 22.765 millimeters, meaning it pretty much fills out shotgun magazines the same way its buckshot counterpart does (you could carry one extra in a Benelli, Remington, or Mossberg).

    Presumably the shotgun grenades would have the same mass as the slug, and the same amount of propellant. There's basically no easily available information on the 20 mm kind, but I find that an "air burst" 40 mm grenade contains 32 grams of OCTOL (air-burst seems to be the main thing the OICW would've been used for—same seems to go for the less-experimental, or at least less canceled, Daewoo K11 and Chinese ZH-05). Now, ONC (not denatured this time) is six-elevenths more effective than OCTOL, so to get the same explosive yield requires only 20.71 grams; the rest is the casing and fuze. The armor-piercing type of 40 millimeter grenade requires 45 grams of Composition A; ONC is 48.75% more efficient than Composition A, meaning it'd take a full 30 grams to make an AP grenade (presumably they can miniaturize the fuze and make an ultra-light casing, it's the 24th freaking century).
  • Do you remember my coil vulcans? They use the "gatling" mechanism to reduce wear on the coils. Well, it occurred to me, the likely ammunition for that gun, whether vehicle-mounted or carried by powered-armor troopers, is something like the Raufoss Mk. 211 High Explosive Incendiary Armor Piercing round, which uses a steel core and a tiny amount of RDX to accomplish, in a .50 BMG round, effects you usually need 20 mm to achieve. Of course, being a coil-gun round, some of it's going to be different—it'd probably have at least a small amount of exposed iron, for instance (maybe a "driving band" like on artillery shells?).

    Average troops equipped with lifting exosuits could use it with a tripod, maybe, though I don't know of anyone who's used the GAU-19 (chambered in .50 BMG) that way—and the Soviet Yak-B machinegun is only used on the Hind. You would need powered-armor troopers to use the thing without a tripod; the recoil of the GAU-19 is 2.2 kilonewtons at 1,300 rounds per minute, but goes down to 1.7 at 1,000 rds/min and up to 2.8 at 2,000. It takes about 2.7 kilonewtons to knock over a 113-kilo man (a basketball player, specifically, in what's basically a horse-stance); therefore, it takes only 1.7 kilonewtons to knock over a 70-kilo man in the same posture (not that you stand like that while shooting a machinegun). Presumably for handheld, or even mere tripod applications, you'd keep the rate of fire at 1,000 rds/min.

    A thousand Raufoss-equivalent rounds would weigh 43 kilos; each link of a disintegrating belt weighs about 2 grams, a thousand of which is another 2 kilos, bringing the total to an even 45. The GAU-19/B weighs 48 kilos, so you really want that power-lifting exosuit—which may also be necessary to using the thing by hand, I wouldn't be surprised if the reason nobody uses .50 BMG tripod guns now is the sheer difficulty of pointing the thing. (By going with titanium instead of steel, the links could weigh as little as 1.1 kilos; and if we use polymer like the LSAT—which you may have to, with caseless—1,000 links weighs only 500 grams.)
  • One thing I realized, since my setting's "assault rifle" is chambered in something that approximates .30-06: they don't need much special equipment to be a "designated marksman". So, in my setting, there is no DMR; they just attach a bipod and scope to the standard assault rifle via its accessory-rail.

    Since it's a bullpup AK-type assault rifle, I guess it looks like the Polish Jantar carbine (prototype/demonstrator). Or, even more, like the Kalashnikov Concern AS-1 and AS-2, of which there seems to be, more or less, one image on the whole internet. (Your guess is as good as mine why they're green.)

    While I'm at it, the bullpup ARs my USMC uses, are basically like this, the K&M Arms modernized Bushmaster.
  • The main underbarrel grenade-launcher used in my setting is also a shotgun, like a cross between the M26 Modular Accessory Shotgun System and the M576 buckshot grenade in reverse.

    It occurred to me that my Peacekeepers would classify all their shotguns as grenade-launchers—because it's no longer the least bit remarkable that they can be used for 20 millimeter grenades. It's not that uncommon to classify things oddly, in militaries; several Russian shotguns are designated as carbines, and not all of them have rifled barrels like the KS-23. Or how about the US's pathological aversion to the words "light tank"?

    I'm not sure how prevalent 40 millimeter grenades are, for my Peacekeepers, though zledo use their equivalent here and there. I suppose the humans probably prefer the 20 millimeter ones for the high end of "small arms", and use the 40 millimeter grenades for their equivalent of the Mk. 19 grenade machinegun (and its successors).