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Toxn

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  1. Toxn
    It's actually better than that, because equipment has a TE in this competition. But on the other hand, check the requirements - crew survival is third. Think very carefully how wrecking the tank to save the crew will work if your primary task is to keep on fighting and just replace dead crewmen as necessary.
  2. Toxn
    What's your array design? I'll happily double-check it for you. BUT, as we saw earlier, you shouldn't trust my numbers either...
  3. Toxn
    The ancient ways must be respected.
  4. Toxn
    Your most serene radiance, rest assured that we have already considered this very issue and requested our sister Auditors in the Department of Rocketry to develop and manufacture a suitable engine and associated fuel tanks, pumps etc. Unfortunately, our most learned sisters have since informed us telephonically that it may take a significant amount of time for their engineers to miniaturise the A-series tanks and motors to fit a sub-133mm form factor. We would accordingly humbly ask your assistance in motivating the various Auditors involved to apply their full effort to the project given their shared enthusiasm with the advantages it could provide, and eagerly await news from them of any further progress. We will of course happily provide whatever humble technical assistance may be necessary (including providing blueprints of our existing gun and shell designs, and detailed requirements for the motor's thust and specific impulse) to assist our sisters in these endeavours going forwards. Here we should note that we have also taken the liberty of approaching the Department of Aero Engines for assistance in designing and producing a suitable ramjet engine for use as a motor to drive an armour-piercing shell from our existing 133mm gun. This project would, we feel, provide a secure backstop should our most respected sister Rocketry Department Auditors encounter unforseen technical difficulties in achieving their promised goals. Until then, in the interests of beating back the phallocentric Cascadian dogs who even now threaten our Northern border, we have elected to press forward with production of the present shell and motor configuration purely as a stop-gap measure. By the grace of Hubbard, our sisters Auditors will soon deliver a technological marvel to assist us in our fight, but until then we are committed to pressing on as quickly as possible for the sake of the security of our glorious Dianetic People's Republic.
  5. Toxn
    What, and sit for a few minutes puffing on it like the world's biggest bong? The crew has many more worryingly toxic things nearer to hand to deal with in any case. A few wisps of rocket exhaust getting into an open breech after the fume extractor has done it's work is something like 100th place on the list of things that will give ex-tankers cancer.
  6. Toxn
    Visually it just needs a wonky sight with strangely-spaced range markings, same as an RPG-7. Calculation is no more or less complicated than normal, at least as far as I know. In terms of accuracy, that will mainly depend on the reliability of the motor. There's only one, though, so there should be less issues than in, say, a cluster arrangement. The rocket is ignited in the bore but the shell should be outside before anything noteworthy actually happens since it takes a certain amount of time for the motor to develop thrust once ignited. The exhaust is probably not good to breathe in, but then if you're close enough to suck in concentrated exhaust fumes you're almost certainly near the muzzle or the path of the projectile and thus dead. The rocket should indeed leave a hilarious smoke trail pointing all the way back to the muzzle of the main gun, and frankly the mental image is too funny for me to bother looking for an alternative low-smoke propellant.
  7. Toxn
    So I think I've pushed the RAP-FS concept about as far as I can in this gun configuration: The core is now two 30x350mm rods threaded together. The forward rod has a 13x51mm tungsten carbide bit in the front (underneath a fibreglass cap), while the rear rod screws into the nozzle for the rocket motor. The entire assembly is now somewhat undersized in the bore, with a set of forward fins to stabilize the front and a combination of the rear fins and a rear buffer to stabilize the rear. The fins are now fixed. The whole assembly weighs 8.8kg, with the pad weighing around 500g. The RAP-FS round leaves the barrel at around 1900m/s, with the rocket motor being ignited in the bore via a flash hole in the pad. The rocket burns for around 1.5 seconds after ignition, and is capable of boosting the assembly to around 160m/s from a standing start. In practice, it serves simply to offset the drag of the shell assembly, keeping the round moving at more-or-less its initial speed for around 3km before falling off rapidly. As a result the round has a very strange trajectory. Penetration is around 420mm RHA at the muzzle, with the more slender tungsten bit providing a fair proportion of the overall total (around 78mm). A side effect of the way the shell is constructed is that the steel walls of the outer shell itself make a fairly potent anti-armour weapon. This might result in secondary penetration of as much as 130mm of RHA in a ring around the core assembly, with suitably impressive levels of spalling and shrapnel generation. If the round impacts the target before motor burnout, any remaining unburned fuel also turns into a rather impressive incendiary as it gets pulled into the penetration pathway of the core and/or outer shell. As a result the RAP-FS round is very effective at dealing with light vehicles and bunkers at shorter ranges. Edit: optimising and calculating the penetration turned out to be a bear, as the way I set up my spreadsheet every change in rod parameters sets off a cascading series of mass and velocity changes that have to be accounted for. Right now, the way I'm doing it is to take the length of the rod, minus the length of the tungsten tip, adjust the parameters until the velocity matches the original velocity, take that penetration, divide by 1.15 and then add in the penetration of the bit at the correct velocity.
  8. Toxn
    Speaking of which, wouldn't it be great if this competition ended being decided by a RAP battle? I'll see myself out now...
  9. Toxn
    Yes, yes! Let the weirdness begin!
  10. Toxn
    This is the reworked version as it stands at the moment: The length has gone down to around 550mm, while the mass has gone up to around 16kg + 1kg for the pad assembly. The performance has accordingly dropped to about 330m/s from a standing start. The core assembly is now held front and rear, and forms part of the rocket nozzle. The starting velocity is now 1370m/s, going up to perhaps 1600m/s. The penetration is something like 220-310m/s. A bit disappointing, but we'll work on it. Edit: so something I just realised is that once you anchor the shell casing to the rod at two ends, it effectively stiffens the whole thing. Edit 2: I also realised that you get more bang for your buck by saving weight than you do by chasing higher thrust. This is the further revised version: Penetration is up to around 330mm at the muzzle, while weight is down to around 9.8kg plus a 1kg rear cradle. Initial velocity is up to 1700m/s, which is very respectable. The motor provides enough thrust to reach ~250m/s from a standing start, which is getting to the point where I suspect that it's only going to sustain velocities rather than boost them significantly. Nevertheless, you might see up to 360mm of penetration at maximum here. The motor is used for simulation purposes burns for around 1.5 seconds, so the rod will be around 3km out before velocity starts dropping off. The front assembly is supposed to be aluminium, and tapers from a wall thickness of 2mm to 5mm at the joint. The rear body is 5mm carbon steel, and the assembly is constructed so that the rod pieces effectively brace the whole structure. The entire assembly is actually slightly undersized, with the cradle acting to centre it in the bore (I may consider adding a set of stub fins to the forward body as well). The rod pieces themselves are segmented, with the forward rod having a tungsten bit in it. The final penetration is calculated by lowering the initial rod performance by 15% and then adding the tip performance on.
  11. Toxn
    The design is, shall we say, provisional. I would appreciate any guidance you or anyone else may have on how best to configure the round, as I'm well outside of my sphere of knowledge here and working with fairly limited tools. The propellant for the rocket is some version ammonium perchlorate composite, for which a wealth of surviving literature exists.
  12. Toxn
    Yeah, no kidding. I actually had to downgrade my 133mm gun a bit, as checking it against the available pressure limits for 2A46 (510 MPa for earlier versions of the gun) showed that it was going over. Bear in mind that this configuration was selected precisely because it has the maximum possible penetration using conventional AP. So, for instance, if you run a similarly pressure-limited 152mm AP shell (based on BR-540B), you get something like 216mm RHA penetration at 2000m. Edit: hold the fucking phone, because I just had an idea. I'll revert if/when something comes of it. Edit 2: Okay, here it is I'm calling it the "Sustainer" shell. It's essentially a rocket motor and shell wrapped around a completely conventional armour-piercing core. The shell has a set of folding fins on the back, while the core has a small tungsten bit on the front. Testing using Rocketsim lots of math by actual rocket scientists shows that the entire assembly would weigh around 12.5kg and produces enough thrust to hit over 500m/s from a standing start. Behind the shell is a buffer pad to keep the entire thing from disintegrating, and behind that a powder charge. The entire thing is loaded as a warhead section in front of a standard propellent charge and shot out of the gun at around 1580m/s. From there on the rocket motor kicks in and actually speeds the projectile (potentially up to around 1900m/s) before simply sustaining the velocity. Penetration is accordingly a bit weird, starting off at around 300mm RHA equivalence at the muzzle, and then rising to perhaps 395mm a kilometre and a half out. From there it holds more-or-less steady out to 4km, before rapidly dropping off. This new type of shell, which we're thinking of referring to as "Rocket-assisted AP, Fin-Stabilised" (or RAP-FS) is expected to provide substantial penetration performance while maintaining a non-phallic, mammaric appearance.
  13. Toxn
    So I think I just T-72'd myself. The backup is looking really, really good. Edit: really, really, really good It developed from the same philosophy that informed the Big Buoy tank concept, so it's been provisionally dubbed 'Lil Buoy after the pre-war mythological figure. So far the weight estimates have it at 71mt fully loaded, with the same 133mm gun and stretched AVDS-derived engine as the Brick (2950kg dry mass, 1205HP). This gives it a power-to-weight ratio of just under 17HP/mt, which should bump it over the minimum requirements in that department. It also has the same autoloader setup as the Brick, with 20 complete rounds in left side of the turret and another 10 in the left front ammo rack. If needed, the turret crew can now manually serve the gun (although this would obviously only be in case of emergencies or malfunctions). The gun itself fires AP-FS, HE-FS and various types of HEAT-FS. The AP-FS can comfortably exceed the new penetration requirements, to the extent that it can penetrate the turret armour of a Norman-series tank from the front at 2000m. 133mm ammunition: Common: seperate propellant and warhead stages, semi-combustible cases. The propellant stage is 150x1000mm and has a steel case stub. The warhead stage is 133x1000mm bottlenecked to 150mm at the base. Warhead stages may have extra propellant. AP-FS: 34kg, 960m/s, 265mm RHA penetration at 2000m (130mm BR-482B used as reference) HE-FS: 35kg, 835m/s, ~45-50mm RHA penetration HEAT-FS (single, steel cone): 35kg, 835m/s, 430mm RHA penetration HEAT-FS (tandem, copper cone, improved explosives and pressing, higher cone precision, wave shaper, improved detonators etc): 35kg, 835m/s, 230/615mm RHA penetration
  14. Toxn
    Kicking off; I've been on a dead tree media binge the last few months, as I've given up on kindle. My current bedside table book list is: The great leveller (Walter Scheidel) Utopia of Rules (David Graeber) Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness (Peter Godfrey-Smith) Ring of steel (Alexander Watson) 1177 BC: the year civilization collapsed (Eric H Cline) Oathbringer (Brandon Sanderson) War and peace and war - Peter Turchin Egg & Spoon (Gregory Maguire) Grace of Kings (Ken Liu) So far I've read up to Oathbringer (which is good, but has the typical issue of needing to have read all the books before it to get all the value out). Edit: I'll post little reviews of the above more or less at random going forwards.
  15. Toxn
    I think there may be an older version of this thread somewhere, but if so it's buried. Post short reviews of books you've read recently, along with any particular points of interest that may be pertinent to the other denizens of this forum.
  16. Toxn

    Oddballs

    Toxn replied to Toxn's topic in Biosciences

    I cannot believe I never knew about these things until now: https://en.wikipedia.org/wiki/Nycteribiidae
  17. Toxn
    *Casually chats about the weather after we 'happen' to bump into each other outside in the park (on a suitably windy day) until I'm certain that nobody else is nearby* I'm fully aware of that. Which is why my 133mm gun, which is what I'm actually putting on my tank right now, does 360mm from 2000m. Which most certainly can kill a Norman, and can probably kill an uparmoured one from a bit closer to even with full-bore stupidity rounds. If you look at my other gun (the 150mm piece) it is and was always optimised for HEAT and the AP round we lashed together barely punches through 200mm on the flat at distance. And even that took a painful redesign of the gun and its cartridge. I'm making other people aware of the minimum level of gun needed so they can go about their day unmolested and then say 'whoops, guess what we just happened to have lying about' when a certain someone succumbs to her increased stress levels and ever-harder-to-hide amphetamine addiction and we can all use finned sabot again. Barring that, a 122mm gun slinging our most up-to-date tandem HEAT-FS can do 200/500mm. Meaning that it will go through a Norman with bolt-on ERA like butter until such time as the perfidious Cascadians add in a NERA interlayer. Finally; if you run the numbers on a fully upgraded Norman (ie: with the bolt-on RHA removed and NERA/ERA added all over the shop) you'll find that nothing short of 550+mm of KE or something like a 190mm diameter tandem HEAT shell has any hope of killing it from the front. Which means that either you sling APFSDS and damn the consequences, or resign yourself to throwing artillery shells at the thing and hope that Her Serene Majesty won't notice that the turret got pulled off by explosive mass rather than any sort of armour piercing effect.
  18. Toxn
    I managed to mail myself the file for Brick junior and got working on upgrades: Xer now has the high-powered 133mm L/50 gun, which was developed specifically to beat the base Norman armour spec out to 2000m using AP-FS. The dimensions of the cartridge are compatible with the existing 150mm one in terms of ammo rack space, so the ammunition load is the same. The new gun also has a muzzle break and fume extractor, both of which are more to allow compatibility with other projects than anything else. The Brick jr now also has a larger 16-cylinder AVDS-derived engine, which should put out around 1200HP. The weight will have gone up by a few tonnes (I haven't recalculated all the values again), but this should be more than offset by the increased power. I think Brick jr is more or less in xer's final form now, and will work on the backup project (which is supposed to use a more conventional turret) for the next little while.
  19. Toxn
    Object 958...
  20. Toxn
    I don't have access to my primary computer for a while, so I've been dicking around on my laptop: This is Big Bouy, which has two AVDS engines, a 200mm gun, and an exceedingly low likelihood of being a sensible weight.
  21. Toxn
    I honestly forgot about the T-10M...
  22. Toxn
    So in case anyone is wondering (not that I'm advocating anything for or against anything), the minimum specs needed to punch through 203mm RHA sloped at 20' degrees from vertical at 2000m is: - 122m gun, ~12.3MJ muzzle energy - 25kg APBC, 992m/s (mass and penetration based on 122mm BR-471D) So this can in principle be achieved using a hot D-25T
  23. Toxn
    L-O can be calculated against targets with different densities and hardnesses (to a point), which gives you an idea of the KE mass and thickness equivalence of many bulk materials. I've used this in the past to look at how efficient bone or diamond might be as armour materials, for instance.
  24. Toxn
    So OOC (note: all in-character stuff will be in comic sans from now on) but I feel like this competition has made me properly understand some of the dilemmas of modern AFV design for the first time. There's nothing like designing something and running the numbers yourself to give you a visceal understanding of it, and seeing just how much reactive armour elements add to the mix (and how much tandem charges fuck things up) is impressive. I think the key difference is that, heretofore, we always used simple modifiers of RHA effectiveness to represent the active armour elements. And these simply don't capture what's going on very well. So I'd like to thank @N-L-M and company for the learning experience going on here. It's appreciated gents (and trans-gents, ladies, transladies, gender-neutral conglomerate entities etc).
  25. Toxn
    Yup Let too many bacteria grow on it and it rapidly (exponentially, in fact) starts to accumulate computing power again.
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