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I was a tank crew conscript on the Leopard 2 twenty years ago. There were various issues with the tanks but while the transmissions are probably super complicated they worked just fine, to the point that all we ever learned about them was "this is how you drive" and "this is how you decouple the transmission from the drive sprockets to help the mechanics change the power pack in a hurry in the field". e: lovely snipe sorry
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Mar 30, 2021 17:27
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That seems to be the German way of doing things. Make a machine that is generally quite reliable and effective, but also unbelievably complicated so when it breaks there's no way you're fixing it, so you just pull out the entire thing and send it back to the factory and plug in a new one. See also: the HK G11 caseless assault rifle that was very nearly brought into service with the German army. It comes apart into five easy pieces:  1. front grip 2. receiver 3. buttstock 4. magazine 5. every mechanical part in one giant clockwork glob that you just replace as a unit if anything goes wrong
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Mar 30, 2021 19:16
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"Kraut space magic", as gun Jesus called it. https://www.youtube.com/watch?v=QGKcvM2Hh4g I believe it works fine when it works, though?
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Mar 30, 2021 19:20
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Computer viking posted:"Kraut space magic", as gun Jesus called it. Besides heating problems due to not actually having a way of dissipating heat in any way as convenient, as throwing out the hot shell and having an actual opening, yes.
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Mar 30, 2021 19:46
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I get why you'd think this about German engineering. I've wrenched a bit on their cars and have found some lol-worthy needlessly complicated things that caused problems a "normal" car simply wouldn't have. A leaking diesel return cooler for example. Or the mysterious case of the old mercedes with coolant going into the windshield washer fluid. There are exceptions though. The same company that made the G11 also made the G3 which is a simple and sensible design according to the same Gun Jesus https://www.youtube.com/watch?v=lvx2RFkst4U As for the Leo 2, most of the issues we had were from having tanks from early on in the Swedish licence built production run. Bad wiring decisions on some aftermarket addons and a bad batch of road wheels losing their rubber, mainly. Also an incorrectly installed torsion bar on a foremost road wheel pair - that tank (not mine thankfully) threw a track if you looked at it wrong before someone reluctantly took responsibility and fixed it. In my company we probably drove about 20000km in total with zero powerpack issues - the need for easy swapping makes a lot of sense if people are trying their best to shoot and bomb you and everyone's in a hurry I guess. The only tanks that spent any real time in the workshop were both from user error. One got high centered at speed on a boulder hidden under snow that bulged in the bottom armor. The other was killed by a commander (not me!) who's belt knife got eaten by the turrent monster and managed to short out the power feed for the turret slip ring. Lots of current in that cable.
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Mar 30, 2021 20:43
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Lost a water pump pulley bolt while changing other pulleys on a 93 ranger. Carquest gave us this:  I have concerns. Wish I'd been present at the store to laugh at it and leave.
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Mar 30, 2021 20:49
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Invalido posted:belt knife got eaten by the turrent monster and managed to short out the power feed for the turret slip ring. Lots of current in that cable. 
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Mar 30, 2021 20:56
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Invalido posted:I get why you'd think this about German engineering. Over-engineering things and processes is one of the nicer, and definite, stereotypes most people have on Germany and on how they design or run things. Or do comedy.
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Mar 30, 2021 21:10
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The problem they ran into was basic physics yes
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Mar 30, 2021 21:11
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I had a G3 (ok, an AG3) as a service weapon for a full two weeks before I moved to some pleasantly slack office duties. That poor thing had been manhandled by thirty years of recruits and was still in good working order, and I managed to take it apart and put it back together blindfolded in what, two minutes? So yes - the G3 felt like a good design. The bolt was a little bit weird to put together, IIRC.
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Mar 30, 2021 22:43
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Computer viking posted:I had a G3 (ok, an AG3) as a service weapon for a full two weeks before I moved to some pleasantly slack office duties. That poor thing had been manhandled by thirty years of recruits and was still in good working order, and I managed to take it apart and put it back together blindfolded in what, two minutes? The G3 is widely regarded as a very good service rifle. The G11 was, thankfully, never adopted, nor was ANY caseless ammo system AFAIK.
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Mar 30, 2021 22:46
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Combat Theory posted:We made this into a successful product so of course. Yo I head you like epicyclics... I think I follow most of it; the pair of yellow bevels threw me for a minute but you engage one or the other for forwards or reverse, right? And so you have four(?!) identical gears in both directions? What's going on in the top left corner? I can't quite interpret what the purpose of that bit is. *E* I should point out that I know transmissions but the only technical German word I know is 'kupplung' because I find it amusing. 
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Mar 30, 2021 22:51
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What I've read suggests they fixed the cookoff problem in the end by creating very insensitive ammunition instead of changing the cooling, but I guess that may have been optimistic sales talk from HK instead of entirely true? Having a tightly packed magazine of square ammunition without half the weight being scrap brass does sound like a great idea on paper, so I understand why they tried. Oh well - if the GDR had lasted five years longer, maybe we could have had the German army be guinea pigs for us.
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Mar 30, 2021 22:55
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jammyozzy posted:Yo I head you like epicyclics... A Lüfter is a fan or ventilator, i think (since Luft is air), with some sort of hydraulic clutch?
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Mar 30, 2021 22:58
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It translates to "fan drive" maybe an air pump or engine cooling fan PTO? E: or supercharger, but why is it coming off the transmission? Cooling fan just for the trans?
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Mar 30, 2021 23:50
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Elviscat posted:It translates to "fan drive" maybe an air pump or engine cooling fan PTO? It's the blower motor for the crew compartment heater. Prove me wrong.
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Mar 31, 2021 00:26
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sharkytm posted:It's the blower motor for the crew compartment heater. Could be both, VW Beetle style?
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Mar 31, 2021 00:45
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Elviscat posted:It translates to "fan drive" maybe an air pump or engine cooling fan PTO? I think that’s it - there’s one on each side and the power pack is a two-fan system when installed (I think). I don’t know if they use one PTO per fan but it’d make sense from a redundancy perspective.
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Mar 31, 2021 00:46
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Vindolanda posted:I think that’s it - there’s one on each side and the power pack is a two-fan system when installed (I think). I don’t know if they use one PTO per fan but it’d make sense from a redundancy perspective. If that's the case, then why do they appear to be tied into the steering control mechanism? If I understand how this works, then the mechanism at the top of the diagram controls the steering by applying rotational torque to the steering differentials (Lenkdifferential) near the left and right output shafts; the transmission drives the ring gear, the steering mechanism drives the sun gear, and the output is connected to the planet gear carrier. When the ring gear and sun gear are rotating at the same speed and direction, then the planet gear carrier will also rotate at the same speed. Speeding up the sun gear will in turn speed up the planet gear carrier. Slowing down the sun gear will in turn slow down the planet gear carrier while rotating the sun gear in the opposite direction will further slow down the carrier to the point that it can be completely stopped when the sun and ring gear are rotating at the same speed in the opposite direction. If I had to guess as to how it works, the Nullwelle (zero wave?) connects the two steering differentials together but are geared to rotate in opposite directions. The Nullwelle is stationary when you want the left and right output shafts to be rotating at the same speed to travel straight. Rotating the Nullwelle so that left sun gear spins faster and the right sun gear spins slower will result in a right turn and vise versa. Having the Nullwelle spin faster will result in a sharper turn. The steering mechanism (Lenkhebel) appears to control the flow direction and flow rate of oil going from the control pump (Rengelpumpe) to the "oil engine" (Ölmotor) which in turn drives the Nullwelle. The control pump appears to be driven by the fan drive (Lüfterantreib) which suggests that it is an additional power input into the transmission. Maybe it's called that because it's part of the engine's cooling fan and accessory serpentine belt or at least maybe that's the etymology. The fact that the transmission input coupling is on the opposite side suggests that physically isn't the case. Looking at pictures of an actual HSWL 354 have me more confused because they don't precisely look like the diagram. Even so, it appears the actual units appear to have cooling fans mounts on top of the transmission that I guess provides cooling air to the engine compartment and radiators. If I had to take a guess, I think this diagram is not a single-plane section view and is in fact a two-plane right-angle section view with the transition between the two sections occurring along the centerline of the output shafts. The bottom half of the diagram is a section view looking at the top of the transmission and the top half is a section view looking at the front of the transmission. That means that the fan drive are in fact referring to the aforementioned cooling fans. As for how power gets to the fan drive, I think the answer is the green gears that have arrows pointing at them as I think this is how the green components in the upper and lower half of the diagram are physically connected. I also have no idea what the exact purpose hydrodynamic steering couplings (Hydrodynamische Lenkkupplungen), which also appears to be driven by the fan drive, are but the layout suggests it's a pair of hydraulic fluid couplings that are oppositely geared to the Nullwelle. Assuming the fan drive is in some way coupled to the engine, perhaps it's a mechanical regulator that limits how sharply you can turn depending on how fast you are going. The faster the fan drive is spinning, the slower the Nullwelle can rotate since the hydrodynamic steering couplings will be applying more opposing forces onto the Nullwelle. As for the transmission itself, it appears to a typical-ish slushbox automatic. This is all guess work, mind you, but with my background in mechanical engineering and experience with CAD touching I have some idea what's going on and why the diagram may be drawn the way it is. Sorry if my explanation is all over the place but I was slowly figuring things out as I was writing this post.
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Mar 31, 2021 04:02
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sharkytm posted:The G3 is widely regarded as a very good service rifle. The G11 was, thankfully, never adopted, nor was ANY caseless ammo system AFAIK. Well thank god Germany replaced it with the G36 which looses it accuracy when it gets slightly warm! Luckily guns don't get warm during use and dont get used in warmer climates! Oh don't worry. It will get replaced by an even better gun any minute now! In fact, its scheduled to get replaced in September...2020...Oh we haven't even picked a replacement? I thought the MK556 was..legal trouble? Patent infringement? Well, just tell the soldiers to not shoot too many rounds to keep the gun cool! Problem solved!
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Mar 31, 2021 07:54
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Shai-Hulud posted:Well thank god Germany replaced it with the G36 which looses it accuracy when it gets slightly warm! Luckily guns don't get warm during use and don't get used in warmer climates!
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Mar 31, 2021 08:07
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Well yeah but the G36 has it bad Reports suggest that the plastic parts of it start to get flexible at temperatures as low as 23C and that at 30C the hitrate at 100m is down to 7% Thank god HK does not have to pay any damages to the german military though on the basis of "well you wanted a cheap rifle, we got you one, you never specified that it should hit things!" Yes, so far the courts have held that explanation up! Shai-Hulud fucked around with this message at 08:39 on Mar 31, 2021 |
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Mar 31, 2021 08:37
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Vindolanda posted:I think that’s it - there’s one on each side and the power pack is a two-fan system when installed (I think). I don’t know if they use one PTO per fan but it’d make sense from a redundancy perspective. Yup. There's two cooling fans on the rear deck located right above the tranny. Not sure how they are powered but I don't think they are electrical so some kind of PTO makes sense.  Edward IV posted:
I thing your analysis is spot on with my experience driving the thing. It very much felt like driving any underpowered old school automatic. The steering was very easy to use too but a little quirky going in reverse, since the wheel inputs are the opposite of when backing up with a car. You'd just drive like normal only looking at the rear camera CRT screen rather than out the vision blocks.  To the right of the driver's seat is a little vertical box. The T-shaped handle on top is a normal-ish looking slushbox stick that went (IIRC) 1-2-3-Auto. The little horizontal stick facing the camera is forward-neutral-reverse, and a mode for making a zero travel pirouette turn whatever that's called in English.
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Mar 31, 2021 08:53
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You guys got me hunting for a G3 again. I already have an FAL I don't need another big dumb 7.62 battle rifle 
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Mar 31, 2021 08:59
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Shai-Hulud posted:Well yeah but the G36 has it bad Meh. Have you done a controlled test? The German gov didn't. The Bundeswehr haven't. Because no one officially has. I think it's largely overblown, and Ian has a video on it. I've never shot one, but the amount of bullshit surrounding firearms is mind blowing. https://youtu.be/MfPHZFsw40M It was also the first 5.56 rifle issued to the German Army, and they were used to the 7.62 G3, which has very different ballistics. sharkytm fucked around with this message at 13:09 on Mar 31, 2021 |
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Mar 31, 2021 13:05
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Tank chat is cool as hell
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Mar 31, 2021 13:42
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Crunchy Black posted:Tank chat is cool as hell There's a thread about idiots in the military, and it answered a lot of questions I'd always had. One such question is what kind of training to you need to become a tank driver, it must be some kind of elite school or something...well turns out it's the kind of job that people don't want and tanks are simple enough to drive that they'll let young marines that don't even have a civilian drivers license do it. This results in all kinds of accidents. https://forums.somethingawful.com/showthread.php?threadid=3894960
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Mar 31, 2021 13:51
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LifeSunDeath posted:There's a thread about idiots in the military, and it answered a lot of questions I'd always had. One such question is what kind of training to you need to become a tank driver, it must be some kind of elite school or something...well turns out it's the kind of job that people don't want and tanks are simple enough to drive that they'll let young marines that don't even have a civilian drivers license do it. This results in all kinds of accidents. You mean there's a thread about the military? I kid, I kid (but only kinda). My experience working with the military was eye opening, and I definitely try to educate people about what the military actually does and who the plurality of soldiers actually are. The amount of horrible mechanical (and personal) failures I can't talk about...
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Mar 31, 2021 14:23
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sharkytm posted:You mean there's a thread about the military? well read that thread, and the older thread, you're not alone in witnessing some seriously bad poo poo. The most hosed up story they got into was the time a helicopter pilot dropped his M9 pistol out the window. Since no one is allowed to lose weapons, leadership made 2 helicopter crews go out searching for the weapon. At night, in hostile territory, with a lot of dust...and then the inevitable happened the two choppers crashed into each other killing like 6 people...all so they could recover a lovely berretta.
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Mar 31, 2021 14:36
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Mar 31, 2021 14:38
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In a very  story with a better outcome, a friend of mine was in the border guards in his time in the army. (On the Russian border; we're not worried about Sweden or Finland). They managed to lose a G3 off a sled pulled by a snowmobile, and then got to spend two days trundling around arctic marshes in spring trying to find it. I think they concluded it must have sank into a mire, which paints a pleasant picture of the conditions.We do also sporadically lose tank crews to drowning after sinking into ponds and marshland, which ties into the "tank drivers are just random 18 year olds out of highschool". Fortunately rare, it sounds like a nightmarish way to go. Computer viking fucked around with this message at 15:17 on Mar 31, 2021 |
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Mar 31, 2021 15:05
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Fortunately we were just sitting in a river in the US, but we had a couple people lose their M9s overboard, also a couple encrypted radios and whatnot, each instance required us to send divers in to retrieve them. The sidearms were lanyarded to their holsters too, making it even more 
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Mar 31, 2021 15:31
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Elviscat posted:Fortunately we were just sitting in a river in the US, but we had a couple people lose their M9s overboard, also a couple encrypted radios and whatnot, each instance required us to send divers in to retrieve them. I worked with underwater robots. Guess what half their duty was? Locating and retrieving lost equipment. 18 year old from Iowa as a guard on a Navy small boat...
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Mar 31, 2021 21:24
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Invalido posted:The same company that made the G11 also made the G3 which is a simple and sensible design according to the same Gun Jesus Even on the G3, we grunts were told to never try taking apart the trigger assembly because we wouldn’t be able to put it together again. Granted, most of us were straight out of Gymnasium and not mechanically gifted. Blame Germany's weird three branched school system.
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Apr 1, 2021 18:49
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Zopotantor posted:Even on the G3, we grunts were told to never try taking apart the trigger assembly because we wouldn’t be able to put it together again. Granted, most of us were straight out of Gymnasium and not mechanically gifted. Blame Germany's weird three branched school system. https://www.youtube.com/watch?v=DA3VsMteAxk Soldiers gonna soldier
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Apr 1, 2021 21:46
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sharkytm posted:https://www.youtube.com/watch?v=DA3VsMteAxk rofl "the good idea fairy"
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Apr 1, 2021 23:48
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Zopotantor posted:Even on the G3, we grunts were told to never try taking apart the trigger assembly because we wouldn’t be able to put it together again. Granted, most of us were straight out of Gymnasium and not mechanically gifted. Blame Germany's weird three branched school system. Oh yeah, that was a "don't open the magic box" up here in Norway, too.
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Apr 2, 2021 05:30
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spotted on the way to the airport yesterday morning. looked like a brand new fleet vehicle. 
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Apr 5, 2021 12:00
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snugglz posted:spotted on the way to the airport yesterday morning. looked like a brand new fleet vehicle. Someone in the factory found a spare circlip, thought "I bet this went somewhere important", and flicked it over their shoulder. "Problem solved".
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Apr 5, 2021 12:59
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That's a common problem with transit vans apparently, rear end issues (heh). A buddy of mine had to have the entire rear axle replaced under warranty on his, but that was years ago. I figured Ford would have fixed it by now but guess not.
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Apr 5, 2021 13:44
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