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Hogge Wild posted:How reliable were the different tank models? How long distance could you drive on average before something broke, and you had to stop? Tanks in general are maintenance hogs, even today maintenance is a daily affair if you are on the move. In WWII you could expect to have to stop every few hours and do stuff like clean air filters, grease basically every moving part, top off engine fluids, check for leaks (Too much is not good, but if it's not leaking it usually means it's empty and you need to fill it), the works. A pair of tracks would last something around 500kms before they got too worn out and stretched, and engine lifetimes where often around a thousand kilometer or less for wartime production tanks. All in all, if you wanted to move tanks around you put them on a train, and strategic mobility of the Blitzkrieg sort would take it's toll rather quickly even without enemy action. Chances are you ain't getting into Berlin from Moscow on your wheels with the tank you started with, even if the Germans leave you alone.
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Feb 26, 2015 21:05
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PittTheElder posted:The Russian preference for round turrets is just crazy distinctive. Anyone know why they do that? Something something autoloader? The bowl shape of Soviet turrets goes hand in hand with the focus on low profile and relatively light weight of their tanks, it's a very compact shape that allows the frontal armor to protect a fairly wide arc from the front, and it's very short front to back, that saves you a lot of weight on the side and top armor. The weight efficiency of the basic design line from T-54 to T-80 is pretty crazy, if you look at a T-55 and a King Tiger side by side, the armor protection is basically the same, they have equivalent firepower, yet the T-55 is literally half the weight. This has consequences not only in production costs and reliability but you also end up with a tank that can go in a lot more places, as you can actually use the bridges and you don't destroy the roads in places with limited infrastructure. Given the size and infrastructure of a lot of the USSR that was rather important.
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Jul 12, 2015 03:33
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So i had a bit of fun with the rally tank thing, and yeah it isn't going to work. Given the horsepower of modern tanks the main thing limiting top speed isn't going to be power, it's going to be the tracks. Track links are a fairly significant chunks of steel, and they move at the same speed as the tank, so taking the top speed of a Leclerc you're asking the links to go from 70km/h horizontal to 70km/h vertical in the radius of the idler wheel, or about 1/40s. That's about 80Gs of acceleration, the track pins are probably not very happy about that, and are creating massive amounts of friction and heat in the process. They probably can't take that for very long. If you double the speed to 140km/h (86mph for you yanks), you end up with 320Gs, which is usually more associated with car crashes than moving machinery. So yeah, no tracked vehicles at highway speeds, unless you massively increase the size of the idler and drive wheels. Tracks are bad for going fast. A BTR is the way to go for your Mad Max fantasies. Kafouille fucked around with this message at 18:19 on Jul 25, 2015 |
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Jul 25, 2015 18:08
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Rocko Bonaparte posted:Didn't the Christie suspension--when connected to road wheels--make the tanks run stupidly fast? I mean, by modern standards, even. Yeah, saw this citation on Wikipedia. 104 MPH in 1931. The point of the Christie convertible tracks thing is that you linked the drive wheels to the rearmost roadwheels with a chain and removed the tracks, converting them to wheeled vehicles. And it doesn't have anything to do with Christie's suspension design, just happened to be the same dude doing both.
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Jul 26, 2015 12:08
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Grand Prize Winner posted:It would have reduced silhouette a bit, I guess? The French one man turrets were not really a tactical consideration, it originated mostly because the spec they were drawn for was basically a Renault FT with thicker armor, that ended up being the Renault R35. Those things were tanks more in the WWI sense than anything else and were meant purely as slow infantry support vehicles, they were extremely slow (with a 14km\h cross-country speed you could conceivably outrun one of these on foot) and did not have radios until the R40 update, they were about as mobile as the foot infantry they were intended to support. For those things the one man turret made some sort of sense as they were mostly there to lob slow 37mm shells at MG nests in close support of infantry, not run independent operations or fight other tanks, so having a dedicated commander was not seen as essential, and having a dedicated loader made zero sense as the rounds for the 37mm were tiny stubby things about the size of a Red Bull can.  (It's really hard to find a period picture of one of those without Germans crawling all other it) That's all well and good until the French army wanted to actually build a tank for it's Char de Bataille concept as a tank that was capable of mobile, independent exploitation operations, having protection from field guns and equipped for fighting other tanks if needs be. Pretty forward thinking stuff in the twenties, and mostly lines up with the Medium tank of WWII. You see, French procurement in the interwar era was basically everything you hear about the US today, turned up to 11. In a brilliant move they decided to contract tank chassis and tank turrets mostly independently, and to different, competing contractors. So for any new tank to have any chance to be produced it needed to be compatible with existing turrets, and new turrets would need to be compatible with existing chassis. And so the turret size of french tanks got inadvertently standardized on .... the WWI era FT-17, since the only turret in production at the time was for the light tank contract, and that was defined with the same turret ring so they could use the FT turrets while they built the new ones. As a result of that shitstorm, the Char de Bataille could not mount a real gun in the turret, since said turret was sized for a 37mm potato cannon. Nor could it have anyone but the commander up in there since he needed to see what was going on. And that's how you get from that forward thinking spec sheet to .... the Char B !  Yes the French army ended up getting the B1 from a medium tank spec for something that was basically Blitzkrieg. That's not getting into the whole thing that was the light tank procurement (14 different models in the competition. 14 !). Or that Hotchkiss was so butthurt that Renault got the contract even when Hotchkiss had basically created the original spec, that they managed to get theirs produced too. They eventually got their asses into gear when it was clear that the guy with the funny mustache was serious but by then it was kinda late.
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Aug 22, 2015 23:18
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From a technical perspective the French tank industry was rather advanced, they had a number of firsts. The FCM 36 was the first tank to incorporate sloped armor, well before the T-34, they abandoned rivets for welded or cast construction before anyone else (except for said B1 funnily enough), Brandt had developed the first APDS rounds witch saw service in 1940 (and helped the Brits own efforts after the fall of France). In aggregate they had the technical capability to build something truly impressive. But between the fact that this technical expertise was split up between a massive number of competing firms, a very complicated political environment, a tightly constrained budget and lobbying Lockheed Martin could take lessons from it was never to be. Even if the French Army knew what it wanted, and it really did not. There were a number of people who wanted modern designs, and were pushing in the right direction, there were a lot of people that wanted nothing more than the FT-17. After all, they had just defined how a tank should be, worldwide, with it. It's kinda hard to see why now, because the FT looks kinda banal today, but that's mostly because how successful the thing was. Half the planet bought them, and it still defines what a tank IS, and the layout of the whole thing, to this day, so much that now when we look at it and it just looks like another tank. In the first half on the 20s, if your country had tanks at all, they had FTs. As for the SOMUA, well everyone seems to have latched on it as GOOD TANK, but frankly i don't see why. It was somewhat faster than the other tanks in the fleet, and the 47mm was a decent enough gun for the time, but it still had all the problems endemic to the French tank fleet of the day, starting with that loving APX turret that is on literally everything. I think it's mostly people going 'Well if i look at the stat sheet that looks a lot better than a Panzer IIIE, it must be a good tank'. It was still stuck on a tiny chassis, with a tiny turret ring, a turret that was way beyond maxed out and still only had one dude in it, no cupola, high ground pressure, bad suspension, the customary reliability problems, zero growth room. And France had plenty of capability to build more. SOMUA didn't. It's not like the French army didn't just procure nearly 2000 tanks made out large castings of similar thickness (R35s + H35s). Really I think that a lot of the problems get down to the fact that the French army had no internal tank design, instead supplying very vague design directives to the 3 million competing firms vying for gov contracts and having them design the tanks. Since most of those firms had never built a tank before, and would never build a tank again, there was very little institutional experience as to how they should design the things, and any feedback they got was immediately lost as they would most likely not design the NEXT tank. And they were not about to give hard won experience to competitors. So French tank design had to learn every single lesson again and again as the current contractor caught up. Given how fast the technology was evolving in the 30ies that is a losing proposition even before you get into how well it fits into combat doctrine. Only Renault had a chance to actually have some continuity but they were happy making incremental tweaks to the FT as long as they could sell them. Kafouille fucked around with this message at 01:00 on Aug 23, 2015 |
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Aug 23, 2015 00:47
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It does save on manpower, but more importantly it saves on size and weight, needing to keep an extra dude under the armor who needs to stand next to the gun and move around to grab rounds takes up a lot of space, so the tank needs to be larger. Not only does this make it heavier for the same armor, but you end up easier to spot and easier to hit too. While the early autoloaders were somewhat slower than a good loader (not by much tho), they can maintain that rate of fire until the magazine is empty, even when the tank is moving over broken ground. There are a few drawbacks but they are mostly about the fact that you have one less crew member in the tank looking for threats, not really about the fact that he loads the ammo. Bonus gif from a T-80 : 
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Aug 23, 2015 10:56
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chitoryu12 posted:Hoo boy. Please remember that every time you refer to the M113 as a 'Gavin' you enable that man. Please don't.
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Sep 1, 2015 09:11
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bewbies posted:I'm sure gun nerds can correct me or expound on this as necessary, but I think the limiting factor was the efficiency of the powder, not so much the amount. In other words, compared to modern powders , Blackpowder expanded relatively slowly, which limited muzzle velocity, which in turn meant that a larger bullet (and longer barrel) was somewhat optimized in so far as maximizing muzzle energy goes. As the powder got better, muzzle velocities rose, and we went able to move to smaller rounds that were more aerodynamic. The issue actually is that the burn rate of black powder is not linear as with modern propellants, but increases massively with pressure. This limits the quantity of powder you can use in a given bore size as you very quickly reach pressures that will turn your gun into a pipebomb, since the powder burning increases pressure and causes the remaining powder to burn faster in a feedback loop (This still happens with modern propellants but much more slowly). Since pressure is sharply limited, you can't drive small projectiles fast. So if you want something more powerful, you have to make the bore larger. Even modern blackpowder hunting guns are relatively large caliber for this reason.
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Sep 8, 2015 04:10
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JcDent posted:Just read that Soveremnyisomething class destroyers of the Russian Navy carry eight anti-ship missiles, as "primary surface combatant" of the RN. Is it expected for engagements not to last that long to need, for ships not last long enough to need more, or what? The only reason it carries only 8 missiles is that 9 wouldn't fit. The Moskit it carries is massive, each one is more than 4 metric tons, you could carry 5 Harpoon missiles for each Moskit. When you add those plus the heavy gun armement (Most ships that size have one main gun these days, it carries 4), it's the ship with the heaviest ship to ship armament currently in service. The thing is the Sovremennyy are an exception, most ships today are not expected to be the primary means of sinking other ships. That job is best left to aircraft, as they can patrol a vastly larger aera, can strike much faster, engage from greater range (Since the missiles get a large boost from the altitude and the speed of the carrying aircraft), and you 'only' risk planes with one or two people in it, not a ship with 300+ people on it. This is one of the main reasons why carriers are such a big deal, another being that they can 'own' a very large chunk of sea, thanks to patrol aircraft, while a surface combatant can't really see over the horizon.
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Sep 10, 2015 17:58
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I actually thought they Kirovs were all in mothballs but yeah there is still one in service, my bad. Those things are kinda mental, but i find it hilarious that the US reactivated 4 Iowas because of them. Can't have the Ruskies having the biggest ship (Nevermind the carriers that are actually useful), just slap some missile launchers on a WWII battleship so we can pretend it's still useful. Who cares if it can't fire the main guns without blowing most of those away, we have a dick contest to win.
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Sep 10, 2015 19:13
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Murgos posted:The Missouri fired it's main guns and Tomahawks within a few days of each other during GW1 support missions. Where are you getting that from? I can't seem to dig up the source right now, maybe i'm wrong but i remember reading that they had massive trouble with muzzle blast from the main guns caving in Phalanx radomes and tearing up a lot of the retrofitted equipment. The Tomahawks would have been fine given that they had dedicated hardened launchers, but a lot of the upgraded equipment just couldn't take it, especially the various antennae. As for the value as a Tomahawk platform, i guess it could do that but is it really worth it to have a 58k tons battleship and it's crew to haul around 32 Tomahawks ? The Ticonderoga class was in service by that time and the ones built after 1985 have 122 VLS cells capable of hauling those on a ship that is 6 times lighter (Not that you would load all 122 cells with Tomahawks, but still.). Even some Spruances ended up with 8 of those on board, and that's before the VLS upgrades. It was purely about 'Look at dem big guns', not any actual combat capability.
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Sep 10, 2015 23:04
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MikeCrotch posted:Also you don't need to worry about hurting LockMarts There was plenty of competition and infighting between firms in the USSR too, hell the T-72 mostly exists because Uralvagonzavod really wanted to muscle in on the dirty Ukrainians of the Kharkov design bureau, and had an opportunity after the T-64 ended up having engine issues.
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Sep 30, 2015 17:27
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SeanBeansShako posted:I kind of amused and saddened that the respect for the common French soldier seemed so low at the turn of the 20th century, I'm guessing this is one of the after effects of the Franco Prussian War? You .... could say that, but it's probably not in the way you picture it. The Commune old Barthas is referencing is the Paris Commune, one of the early cornerstones of the communist movement, who had a strong following among the French working class. The rise of said Commune was a direct result of the loss of the Prussian war, but the real influence was the retaking of Paris by the French army, an intensely bloody and bitter affair. By the time of WWI the French armed forces have a fairly long tradition of being used as a blunt instrument to quell such things, (not just Communists, mind). As such the officers had to be reliable people, so they trend strongly towards the old school Monarchists and traditionalists, while a lot of the working class common soldiers were Republicains and Socialists/Communists. With the Dreyfus Affair and it's repercussions driving an even deeper divide between the left wing Republicains and the conservative, Catholic right wing in the years between WWI, it's not hard to see why the tensions ran high, and that's before the whole trenches and barbed wire thing. And that's not going into the tensions between the now left-wing Republicain government and the Army, who was now considered unreliable and potentially dangerous to the continuation of the Third Republic.
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Oct 1, 2015 04:03
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Paratroops in general are something that seems incredibly attractive to military planners as a concept but is remarkably terrible when actually used. Does anyone even still seriously expect to use paratroopers in the nominal 'jump out of a perfectly good airplane into enemy territory' instead of as elite light infantry ?
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Oct 12, 2015 14:57
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bewbies posted:Short answer: yes. Longer answer: I don't think that anyone is under the impression that a bunch of C-17s are going to cruise into territory covered by a modern IADS and drop a couple divisions worth ala Normandy. Modern airborne operations are thought of mainly as complimentary to supporting land operations, more useful due to the strategic mobility of the unit rather than the actual jumping out of the plane. I'm confused here, is the main role still expected to be jumping out of airplanes under a parachute ? That's what i meant initially, but you say yes, then no. (This is not meant to be passive aggressive or anything i'm genuinely interested)
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Oct 12, 2015 18:11
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AdvancesMONKEY posted:Armord Personal Carriers: WHY DO THEY EXIST. How where they developed? How where they deployed both on paper and in the real world? I assume it shields infrantrymen from artillery shrapnel and other nastyness but I assume there is a real technical problem when it comes to driving around that much armor. What do half-tracks haft to do with it it? Everyone talks about tanks but how are you going to get your infantry support there? TALK ABOUT THEM FUCKERS TALK. APCs were developed alongside tanks ever since WWI, since it became obvious early on that you needed infantry with the tanks to actually acomplish anything, and they needed protection, leading to the Mark IX :  This was purely for protection, as those things had limited range and could not move faster than a walking soldier in any case. The idea of an APC as well protected as the tanks was then dropped, mostly due to prohibitive cost. As technology improved in the interwar years came increasing motorization, but this was mostly directed at replacing horses in pulling artillery and supplies from wherever the supply train or ship dropped it to the frontlines, not moving people. Since trucks of the period had no offroad capabilities to speak of, most of the armies of the time adopted some sort of tracked vehicle to do the job. Most ended up with some sort of modified tank chassis for pulling the heavy artillery, and things like the Universal Carrier for light guns and supplies.  Note how tiny it is. It's for carrying things, not men. That's also where the halftrack appears, mostly thanks to one Adolphe Kegresse who invented a very simple and cheap track system, that could be adapted onto basically any existing car or truck chassis.  Here is a Rolls-Royce Silver Ghost so modified, belonging to some Lenin dude. Most militaries immediately jumped on the concept, as it meant they could use lightly modified civilian trucks, making things vastly cheaper than purpose built tracked vehicles. The reason the Kegresse system was cheap is that it had no steering, basically simply replacing the wheels, this meant you could use the drive train from a truck, but you had to retain the front wheels to steer the thing. Since militaries had now access to relatively cheap offroad transportation, it didn't take long until people realized you could put infantry into them so they would keep up with the tanks. Since they would have to accompany tanks, they had to be armored, else some dude with a machinegun or harassment fire by artillery could force your whole advance to a halt. The first ones to really try this out were the British, with the Experimental Mechanized Force in the late '20s, but even into WWII most infranty was walking, not riding.  The two emblematic WWII halftracks. Of course the germans being germans, the sdkfz 251 pictured here had most of a tank's drivetrain underneath it instead of a truck's chassis. It was rather overengineered and didn't really need the front wheels, as the tracks had steering. And while the halftracks where armored, they were not intended to actually fight. The armour on these was thin, and you could put holes into them with some persistent MG fire or even a rifle with AP ammunition. The point was to get from point A to point B, and when expecting contact, to dismount in a safe spot and proceed on foot. After all, if you lost the vehicle, the squad riding in it is now stuck in place and most likely useless to you. After the war, around half the known world ended up with US Army surplus M5 Halftracks thanks to the US cranking them out during WWII and then deciding it was not worth the shipping to get them back to the US, but by then the rapid technological advances of WWII had rendered halftracks mostly obsolete, and while they soldiered on into the '50s they did not have the offroad capabilities needed to keep up with the postwar tanks and faded into history. During the '50s and '60s, mostly everyone tried their hand at making their own APCs, and you end up with a wild and weird period where armies adopt a new one every few years as they learn how to make the things actually work properly. The US ended up going fully tracked with the M75, into the M59, settling with the M113, while the Soviets filled the role with the wheeled BTR-60 and tracked BTR-50 after the rather truck-like BTR-152.  The M113 is not named, nor has it ever been nicknamed, the Gavin. Do not call it a Gavin, even ironically. I will stab you.  Unlike most APCs, the BTR 60 has the engine at the rear. This means the troops get to disembark via roof hatches, intead of the common rear door This is not a popular feature, especially if you have to do it under fire. During that time, a lot of the focus becomes about how to enable infantry to survive and fight effectively in NBC conditions, IE after the nukes, so a lot of the development goes into air filtration systems and pressurization of the crew compartment (So any hole leaks clean air out, instead of dirty air in). But then what do you do if you end up meeting the enemy while crossing a contaminated zone ? Enters the IFV. (That's for another post, i am rambling way too much already)
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Oct 16, 2015 02:33
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Nenonen posted:There's also side hatches, as evident, but they're small and there's only two of them. There is actually only one side hatch, on the left side, and it's not exactly large. The design originally did not have a roof, so it made a bit more sense that way, but VT artillery fuses put an end to that.
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Oct 16, 2015 08:07
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That article is the equivalent of someone doing a status report on the US Army by reading GIP. Infantry equipment was lagging at the time simply because France has been trying to make the FELIN boondogle work for the last 20 years, and is finally adopting it these last few years (They equipped the last of the infantry regiments this year), so infantry gear has stagnated while waiting for it. It is deployed by now, and manages to be exactly as ridiculous as it sounds (Computerized sights linked to an LCD eyepiece to shoot around corners. Yes, they really fielded that). It's hiliariously '90s, and overly heavy but i suspect the soldiers will just dump the useless bits and use the actually useful ones, like the Blue Force Tracker-like system and the IR sights. Also the FAMAS ammo thing is a multi-step fuckup : GIAT goes kabloey, the French army must now buy ammo from commercial manufacturers. They buy some off-the-shelf NATO standard ammo, works fine in most things, but not the old first gen FAMAS of the Army, ends up shooting like a musket (They bought 62gr ammo, the first gen FAMAS has 1:11 rifling, that just doesn't work) They buy some more off-the-shelf ammo, this time with 55gr bullets, just for the old FAMAS. Turns outs either the brass is too soft or the pressure curves are wrong, but it ends up sometimes rupturing cases. Then they just say gently caress it and issue the old stock back to people while they just upgrade the rifles. It mostly made news because of the 'DEY TOOK UR JERBS' angle of the Army buying ammo from dirty foreigners. Kafouille fucked around with this message at 04:17 on Oct 19, 2015 |
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Oct 19, 2015 03:38
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Military vehicles are driven by 18 year olds who don't own them and who will get issued another one if it's broken. It's surprising any survive more than 3 weeks.
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Oct 19, 2015 05:29
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JcDent posted:One joke explanation why Marine Corp keeps getting old equipment, no medical check and bullshit tasks is that the command keeps them angry and fighting that way. The real reason the Marines don't get new equipment is that anytime anyone ask them what they want they insist someone should put GAU-8s on F4U Corsairs.
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Oct 19, 2015 13:54
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Fo3 posted:The copper is just a barrier they can't chew through as you say, and something in ready supply not as heavy as iron or steel.
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Oct 20, 2015 14:06
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Well the main reason is that you get to use the main sight of the tank to aim the ATGM, and you get the benefit the the stabilization. That's pretty huge, as the main sight on a tank is going to be about the best one around, and stabilization is great for observation even if you are not firing on the move (You can fire as soon as you have stopped instead of having to wait until the tank is still to find your target and aim at it) The second reason is that tanks don't really have any free space just laying around, and you need to keep the ATGMs somewhere. The natural thing is to keep it with you other ammo, and that means it mush have at least roughtly the same size as a tank round, so you may as well go all the way and fire it out of the tube. Third one is that you can reload pretty fast, and don't have to open the tank up to do so. This is doubly important during the Cold War as NBC conditions were assumed for a lot of these things, and you can't really open a hatch while driving around in a cloud of nerve gas.
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Oct 21, 2015 14:52
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JcDent posted:Interesting how that one text dump, er, dumps on T-64 and T-80, and Ukrainians are both using and updating those two to no end. The way Kartzev dumps on the T-64 is a bit rich really, considering the T-72 simply would have not existed without it, the T-72 prototypes being mostly built out of T-64 parts. The T-64 was revolutionary in it's day, and it pushed the envelope quite a bit. Quite a few of it's concepts worked out, you won't see anyone building tanks without composite armor, and even the West is coming around to autoloaders and the 3-man crew. Some of it did not work out so well, the engine had pretty much the same issues as it's conceptual sister in the Chieftain, and much of the systems were brand new and suffering developmental issues. The T-72 had the advantage of being able to take the concepts and components that worked and to discard the troublesome ones, but at the end of the day it's a cheaper T-64 with a T-34-derived engine and a worse fire control system. The reason the Ukrainians are updating the T-64 is simply the plant that produced them (And also the principal tank design team in the USSR) happened to be in Ukraine, and they kept them when the USSR fell. They inherited a significant portion of the USSR tank design expertise, and Russia ended up having to mostly stop using the T-64 and T-80 for lack of spares. As for the ZTZ-59, well it's a T-54. It's not any better or worse than any other T-54. Kafouille fucked around with this message at 15:57 on Oct 21, 2015 |
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Oct 21, 2015 15:52
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T___A posted:Not true at all. The only thing the T-72 and T-64 share in common is the gun. The finished T-72 doesn't share much parts commonality, that's true, but i was specifically talking about the prototypes, ie the Objekt 172 who started as a T-64 with a different engine and suspension.
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Oct 22, 2015 07:02
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KYOON GRIFFEY JR posted:This is exactly the same dilemma that happened with capital ship construction roughly 1905-1922. That kind of thing happens in basically every engineering endeavor, adding mass anywhere where it must be moved/supported always creates a spiral where you must add more supporting structures. It's particularly relevant in planes, where the weight margins are thin and impact performance a whole lot, but tanks suffer from it quite a bit too. Armor plate is heavy yo. Putting a King Tiger and a T-54 side by side is a nice example of that kind of thing. Those tanks look completely different but they are extremely similar in terms of basic capabilities, the armor protection is nearly identical and the guns are quite comparable. But because of a few differences in the initial layout and engineering decisions (The T-54 mounting the engine in a transverse configuration, with the transmission directly coupled to it all in the back of the tank is one of the main ones), the Soviet design is drat near HALF the weight.
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Oct 29, 2015 23:03
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Mazz posted:This is probably best directed at EE, but was there ever any discussion or explanation for why WW2 and early cold war Soviet armor design seemed to so disregard gun depression? Was it just not considered a useful feature? Did they ever address this point at all that you've seen? From an engineering standpoint, gun depression is expensive. Every degree means you need to make the turret taller, and that means more area to armor. Taking a T-55 as an example, the end of the gun is about 1.3m from the pivot point, and the maximum recoil length is 650mm. So you need about 2m of clear space to be able to swing the gun around and not crater it into armor when you fire. That means that to increase the gun depression from 5 to 10 would cost you around 18cm. A very rough calculation with the T-55 armor profile shows that you need around 85kg of armor per cm to increase the turret height, that works out at 1530kg, or the weight of a car, to increase the gun depression from 5 to 10. And that's with a T-55 armor level, if you need more armor the cost goes up. So in the end, to get to 10 degrees gun depression a T-55 would need to go from 240cm tall and 40 tons to 260cm tall and 41.5 tons. That is a fairly significant increase for something that would mostly come into play while playing hulldown grabass in the hills, something the Soviets were not intent on doing. Also note that for that weight you could also do things like increase the frontal turret armor by around 100mm for example, going from 200mm to 300mm. So it's a legitimate question of spending the weight on armor, or spending the weight so you can use a hill as armor. (Note that this is all back of the envelope stuff, but it should be accurate enough to give a reasonable idea of the costs involved) Kafouille fucked around with this message at 21:57 on Oct 31, 2015 |
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Oct 31, 2015 21:54
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Modern 120mm ammo is really light for it's caliber. The whole round for a M829A1 (Gulf war era US ammo) 120mm APFSDS round is just about 21kg, and the projectile + sabot is about 9kg. A WWII era 122mm from an IS-2 is 25kg for an AP projectile alone.
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Nov 2, 2015 10:21
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Wait, what would that thing even shoot at planes with, it appears to be armed with a Boys AT rifle and a sewerpipe (empty Vickers mount ? The walls of that tube look way too thin to be an actual cannon)
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Nov 4, 2015 09:40
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Xerxes17 posted:Also found and imgur album full of auto-loader gifs: Note that the "T-90" gif in that is mislabeled, that tank uses a T-72 2-stage autoloader, it's a T-64/80 basket type single stage one (And while Kartsev has a point about the driver separation, it's also obviously faster) Also, do you have a source for the LRF alignement thing ? I've never heard of a tank where that kind of thing was not adjustable and it's alignment should be part of the duties of the crew. It may be some distortion of the fact that the T-72 aiming system is relatively primitive and will move your reticle when you enter the range instead of directly adjusting the gun like on the T-64/80 or western systems. So you need to aim at the target, lase, then the reticle will jump by the needed amount to correct the drop, and you have to manually put it back on the target.
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Nov 4, 2015 18:05
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Xerxes17 posted:My personal reading of the situation is that once the T-72 came around, they should have really thrown thier full weight behind the development of that model. It had much greater potential for modernization than the T-64 That's really not the case, the only real difference in potential was the engine and the 5TDF ended up being a perfectly good, compact engine and the 6TDF ended up a fair bit more powerful than anything fitted to the T-72. As far as i know the main reason the Russians slapped all the fancy toys on a T-72 instead of a T-80 is that they could more easily produce the T-72 independently, at the end of the day all 3 tanks are very similar if you're going to upgrade them. In fact didn't the T-80UD end up with the same 6TDF opposed-piston engine as the T-64BM ? At that point it really is a T-64 with a different suspension. Slavvy posted:Anyone? I'm intensely curious about this because I can't picture how you could stop a tungsten penetrator and still maintain some semblance of combat readiness; seems like every hit, penetrative or not, would effectively be a mission kill that forces the crew to bail out and get shot. The way modern APFSDS works is quite a bit different that old school full caliber AP or the early APDS. It's going fast enough that the interaction between it and the armor enters the real of plastic deformation more than anything else. What happens is that the tip of the round basically gets worn away and deposited on the side of the hole, so an APFSDS round stopped by a slab of steel would end up as a much shorter slug of tungsten/DU lodged 60+ cm deep in a hole, from the outside it would just be a 30mm or so cavity. But modern armor is not a slab of steel, that would be insanely heavy. The goal of the armor of every modern tank is not the stop the round cold, it's to break it up in pieces and stop those. The way to do that is to inflict forces on the side of the rod, so that it's own inertia causes it to break apart when it hits something solid. (Picture pressing down on a straw lenghtwise, then flicking the side of it). There are multiple ways of doing it, one of the main ones is to have 'reflecting plates' where you alternate angled steel plates with air, to exploit the tendency of APFSDS rounds to 'turn into' the armor when they hit, so when it hits the next plate it's going slightly sideways. Repeat until satified or you run out of room. Another is ERA, where you basically throw a plate of steel into the side of the rod by packing sensitive explosives behind that plate of steel, and using the energy from the plate getting pierced to detonate said explosive. If you time it right the APFSDS rod will still be in the cover plate when it starts moving and it will get pushed sideways by it. This is also the reason why all the ERA blocks on the front of tanks are always, always angled. ERA doesn't really work versus AP rounds if the plate is at a right angle to the round, as it makes minimal contact with the side of the projectile. There is also NERA, Non-Explosive Reactive Armor. This uses again steel plates, mounted on flexible mounts so that they can hinge and deflect when a round hits, or are backed by a flexible material that will flow to the side and bulge out the armor plate, again causing it to contact the side of the projectile. All of that has the same desired end result of having the incoming round in multiple pieces going sideways by the time they hit the last bit of armor, which is just a big chunk of steel like grandpa Krupp used to make. When people talk about composite armor on tanks, it can mean a lot of things, it doesn't mean it's not primarily made of steel. CERAMICS  and DEPLETED URANIUM get a lot of press but they are not the main defeat mechanism versus kinetic rounds, they just help some stages on the defeat.EDIT : I crawled so far up into my own rear end i forgot to answer the question. A modern tank sucessfully stopping an APFSDS round would look like a small hole in the external armor casing, and then a series of bigger/multiple holes in each successive armor element up to the main armor where you would find multiple big chunks of tungsten/DU embeded in the last element and a quite a bit of dust and various tiny bits of shrapnel rattling around the air cavities. It would not impede the tank in any way. Kafouille fucked around with this message at 01:53 on Nov 6, 2015 |
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Nov 6, 2015 01:44
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Zereth posted:I vaguely remember hearing somewhere that katanas specifically were constructed in a way which made them ill-suited to parrying? I'm not an expert on swords but i know katanas are made from very hard steel on the edge, and softer on the back. Hard steel is very brittle, and will chip and break in chunks with fairly little provocation, so parrying on the edge would not put a small dent like with a better steel alloy but shatter a length of the edge. That would be pretty much impossible to repair, while you can hammer a dent flat and file a new edge fairly easilly
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Nov 6, 2015 01:59
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People hear extremely hard steel edge and they think that it must be better. It's really not, you need some hardness so you can get a good edge but after that it doesn't make it any sharper, and it makes it really fragile. Katanas are an impressive piece of workmanship but that is about making do with the terrible iron ore in Japan. If you can make real steel with a good alloy it's going to be better in every way than the composite the Japanese where stuck with. The Europeans just took note of what iron ore made for good blades, and by process of elimination found the mines where the ore had just the right impurities to make a good alloy.
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Nov 6, 2015 02:13
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WoodrowSkillson posted:The hard steel on the edge of katanas is not all that different then what longswords are made out of, the difference is a longsword is a homogeneous material that allows it to spring back after being bent, at least to a degree before it breaks. That makes them more durable since unless you actually break the blade in half, it will not get deformed. The edge of a kanata is actually fairly different, in that it's a high carbon content hard steel that is not in any way flexible. That's the reason it's not just used in the whole sword, it can not deform and as such is brittle. When i meant shatter i specifically mean the edge, not the whole thing, but yeah i used the wrong term, it would be a crystalline fracture. That's going to leave you with a bit of edge that's just missing, and you can't just weld a new bit on as that would undo the tempering. While any sword can chip it's quite a bit harder to do on softer steel, and easier to repair on homogenous material. Bending making them unrepairable seems weird if the edge is repairable by itself, since the soft iron won't really mind much being bent back, but bending it would destroy the edge pretty thoroughly as it simply cannot do it without breaking. It doesn't make it a bad sword or crap in any way, it's a really nice piece of engineering, it's just that with the materials they had they did have to make compromises the Europeans didn't.
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Nov 6, 2015 02:34
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Xerxes17 posted:Correct, the 5TDF and 6TDF both ended up being really good engines. However, the T-64's future was limited by its initial design premise which was "small and light as possible". I was curious so i took a pair of side on photos, scaled them by wheelbase, and took a few rough mesurements. The T-72 is indeed bigger, it's around 80cm longer, but i'm not sure that would impact the growth potential much knowing what we know now. From the front of the idler to the back of the turret the T-72 is about 25cm longer, and the turret ring is approx the same size as far as i can tell. Most of the size is due to the large engine compartment, since the T-72 engine is quite a bit larger. It would make sense back in the day to think that the T-72 had more growth potential, since a larger engine bay is quite useful and the compact engine of the day had an uncertain future. But since today a T-64 mounts a more powerful engine than any T-72 and doesn't need to change the engine, the tanks as they stand should have similar growth potential for new FCS and addon armor. I think we were talking about different things, i was thinking of the upgrade potential of the tank today, not the design space it offered back in the late 70's. Slim Jim Pickens posted:When you design a new tank's suspension, do you take an existing suspension and make modifications to it? If so, what sort of changes can be made to increase the weight limit of a suspension? Well on tanks with torsion bar suspension your really don't have to redesign anything, you just need larger diameter torsion bars. I think the issue is that if you do that you end up changing about half the components of the suspension for ones that are exactly the same but slightly larger. That's perfectly fine but if you think you have a better idea and want to redesign it it doesn't really cost much more since you're already retooling and making new casts, so it's often done. Kafouille fucked around with this message at 03:41 on Nov 6, 2015 |
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Nov 6, 2015 03:32
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Taerkar posted:Most WWII tanks still had decent enough deck armor to resist the 37mm guns on the Gs. The Stuka wouldn't be diving in so they'd be hitting that top plate at a pretty shallow angle. It was far more about knocking out thin skinned vehicles like armored cars and trucks than actual tanks. Tanks were knocked out, no doubt, but it was not a likely event. Given the numbers he's given, the 37mm would pen a T-34 roof from as shallow as 18 degrees, it would be hard not to have that much when attacking ground targets. Cyrano4747 posted:Got a source on this? It runs contrary to everything I've read about WW2 anti tank operations including poo poo involving British aircraft swinging 20mm cannon. From the British side it's a bit harder, as while PzIII and PzIV only had 10mm of top armor, the data i can find on the 20mm Hispanos point to 24mm@400 yards. That would mean busting the roof armor in a 30 degree dive, not terribly difficult still. The main issue in those is one of accuracy and lethality, while the guns are technically capable of breaching the armour, the roof is a small target at low dive angles while high ones don't leave much time for aiming, and the angle means it can only hit things that are high up in the tank. That will diminish the lethality quite a bit compared to being able to just blow through the side armor, so having capabilities beyond just blasting the top armour is still important. Do note that the 37mm on the Stuka can in fact defeat the side armor on pretty much any WWII tank (The 140mm@200m i see often quoted seems wildly optimistic, but even at half that it's enough for anything that's not a KV or IS) Kafouille fucked around with this message at 04:27 on Nov 6, 2015 |
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Nov 6, 2015 04:05
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The whole point of the Stuka G is that you don't need to dive, the gun is good enough for you to just plink T-34s from level flight anywhere but the front arc. Given that the stuka is a slow plane with a large wing and that the guns aren't terribly heavy compared to a full bomb load, it should be quite pleasant to fly. As long as there are no Yaks around anyway.
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Nov 6, 2015 04:31
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The thing about tankbusting like that is that while the rounds are plenty capable of getting in the tank, actually doing irreparable damage to them is going to be difficult. As far as i can tell you'd need a direct hit on the engine block or transmission or manage to set it on fire to really do it. So if you are engaging tanks that are not currently in combat, all it'll do is make a few holes, sometimes in a crewmember, but the rest would often be able to either go unhindered with a bit more ventilation or make field repairs to limp to a depot for real ones. Actually losing the tank would be rare, but it still has an impact.
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Nov 6, 2015 04:41
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Slavvy posted:Thank you very much for an excellent explanation of how this stuff works! I didn't realise ERA was useful against modern kinetic penetrators; I've always been under the impression that it was only really intended to counteract HEAT. Makes me think that the US and UK must be extremely confident in chobham's effectiveness that the abrams and challenger don't even have provisions for ERA (as far as I know, feel free to tell me if I'm wrong). The US and Britain do in fact make use of ERA on MBTs:   Though not as an APFSDS defense, those are intended to combat HEAT warheads from RPGs and ATGMs. The Soviets invested a lot of effort into ERA and they probably still have better panels, but it doesn't mean ERA is superior to the other methods, at least not versus APFSDS. It works very well, but so does the other methods. As for APS, as far as i know the Israelis are very happy with Trophy and how it performed last year, and wants to deploy a lot more. https://www.youtube.com/watch?v=xLCVi6PVNdY Xerxes17 posted:Ah I see, well any new additional equipment is going to contribute to the weight of the tank, which will stress the suspension on the T-64 tank. As T___A notes here, the T-64 style suspensions had problems here due to the increased dynamic load being placed on them from the extra weight of the engine and the extended hull shape causing them to fail. It appears that the T-72 has a much more sturdy suspension. Given that they had to lengthen the hull and place all the weight increase at the very rear, i would think that the suspension issue had a lot to do with the weight ending up too far back from the last road wheel and it rocking the tank due to the leverage. This would be a significant problem, and the T-72 wheelbase is in fact quite a bit longer (around 45cm more than a T-64) which would fix that. Trying to research this I see a whole lot of slapfighting and accusations, it's apparently quite political and some people appear to think the T-64 suspension was better http://andrei-bt.livejournal.com/3462.html (Andrei is a regular on TankNet and while not an historian he's not a screaming idiot either as far as i can tell)
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Nov 6, 2015 16:18
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JcDent posted:What would the "other methods" be? Reflecting plate arrays, various forms of NERA/bulging plates, things like the ceramic ball matrix in steel the Soviet used, there are a lot of different ways to try and break up kinetic penetrators, plus all the poo poo meant to interact with that like DU or Tungsten layers and air gaps and ceramics. There is a lot of ways to skin that cat but the details on a lot of it are still pretty secretive.
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Nov 6, 2015 19:14
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