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Rheinmetall's New Tank Gun

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As a rough approximation, using sigma equals flexural force over width times depth (for a rectilinear cross section), I get that the increase in maximum axial load will be proportional to the increase in cross sectional area afforded by the thread vs just using ribs.  Using that model the increase is, needless to say, not worth getting excited about.  The thread ID doesn't look to be more than 10% smaller than the OD, 110% squared is 121%, so the cross sectional area difference will be less than that, exact amount depending on thread form and pitch.

When calculating the critical load under which the rod will fail with the use of Euler's critical load, you need the area moment of inertia. Which, for a circle, has the radius as quadrupled.

 

So calculating the area moment of inertia of the rod using your 110% we get:

0.25*pi*(10.4*1.1)= 13452.22 = Irib

 

And for one without the rib:

0.25*pi*(10.4)= 9188.05 = Ismooth

 

Throwing this in Euler's formula (Pcr = (pi2*E*I)/(KL2)): (Values for DM63 rod)

Prib = (pi2*530000*13452.22)/(1*6462) = 168618 N

Psmooth = (pi2*530000*9188.05)/(1*6462) = 115168 N

 

So a ribbed rod will buckle at ~168 kN, while a smooth one will buckle at ~115 kN.

 

Which is a 46,4% improvement.

 

 

...now that I'm done I notice I used the maximum diameter of a DM63 rod, instead of its minimum diameter. Values change, percentage should stay the same.

 

 

Disclaimer: This is a napkin calculation, do not use as scientific basis yadieyadieya, etc.

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German designs have a helical rib on the penetrator which prevents it from buckling or snapping too easily

 

Not entirely sure whether this is a German design (seeing the Asian text), but it does show the helical rib:

EUTzoUh.jpg

 

DM53 is segmented: short-short-long

DM56 is segmented in short-short-short-short-shoer

Of course it's not segmented during fly, but "semi segmented" - heavy tungsten alloys slugs (something like 30mm APDS ammo) are "melti" in diffrent material and coverd by diffrent mettal jacekd.

DM-53 can overcome K5 without it's initiation and overcome double-reactive (IMHO Relikt) armour.

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iQUE3CX.jpg

 

Mock-up of the 140mm round (not sure which one) next to the propellant case for the 120mm L1/M58, the rifled 120mm gun on the conqueror and M103.  As you can see, the ammo for this gun was quite a bit bigger than the ammo for the later NATO 120mm smoothbore, and a hell of a lot bigger than the ammo used in the 120mm L11/L30 rifled guns.

 

L9ILm83.jpg

 

I think the version of the T123 in the experimental T57 heavy tank was to use one-piece ammunition:

T57-1.jpg

 

The 140mm ammunition was also two-piece, which would have limited the length of the long-rod penetrators it could fling.

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lol. Photos were posted on otvaga. Terlikov and Demchenko (Armata designers) spying on Euroweaklings new gun  :D

I love how confident Demochenko looks. Makes you think...

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When calculating the critical load under which the rod will fail with the use of Euler's critical load, you need the area moment of inertia. Which, for a circle, has the radius as quadrupled.

 

So calculating the area moment of inertia of the rod using your 110% we get:

0.25*pi*(10.4*1.1)= 13452.22 = Irib

 

And for one without the rib:

0.25*pi*(10.4)= 9188.05 = Ismooth

 

Throwing this in Euler's formula (Pcr = (pi2*E*I)/(KL2)): (Values for DM63 rod)

Prib = (pi2*530000*13452.22)/(1*6462) = 168618 N

Psmooth = (pi2*530000*9188.05)/(1*6462) = 115168 N

 

So a ribbed rod will buckle at ~168 kN, while a smooth one will buckle at ~115 kN.

 

Which is a 46,4% improvement.

 

 

...now that I'm done I notice I used the maximum diameter of a DM63 rod, instead of its minimum diameter. Values change, percentage should stay the same.

 

 

Disclaimer: This is a napkin calculation, do not use as scientific basis yadieyadieya, etc.

 

What kind of engineer are you? You failed at the basic engineering

 

In order to increase the load, the increased diameter must run parallel continuously to the axis of the rod, e.g. a full rod, not discrete thread like that which is useless because the chain is as strong as its weakest link.

 

Your theory fails, imagine a steel rod with 1m diameter, but has a section with 1mm diameter. From your calculation, that rod is very strong and can not be broken, but actually it can be broken by human easily.

 

The thread is similar to a 1mm rod with many 1m disks attached discretely along its length, the disks are useless in increasing bending load of the rod, even the diameter is huge.

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On 6/13/2016 at 9:08 AM, Xoon said:

It is entirely possible that it is a ordinary gun. It just seems weird to develop a new tank gun, with a new caliber a and with ETC technology around the corner.  It could have been a quick way to up gun Leopard 2s in service in reaction to the T-14, but having a 50% performance increase from the L55 seems hard with a shorter gun. Even if the case it longer,and it is not wider from the looks of it.

there is no more modular part of a tank than the gun.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA476392

even so, low-end ETC is most likely, which only improves accuracy, barring some immense improvement in capacitor density.

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On 7/29/2016 at 11:18 AM, Bronezhilet said:

I'm a better engineer than you apparently, since I do know what a thread is. "Thread similar to a series of disks attached.". ...what.

Also, are you familiar with the term "napkin calculation"?

But hey, welcome to SH I guess.

Better my ass, I am an inventor, enterpreneur, what did you do your whole life on my caliber?

I don't know napkin calculation, english is not my first language so my expression is not that good.

Being an inventor alone is far greater than anything an engineer like you can be, in both technology and financial achievement. Being a great inventor, who can influence the world, change how battlefield is fought, is not even in your dream, loser

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2 hours ago, lemd said:

Better my ass, I am an inventor, enterpreneur, what did you do your whole life on my caliber?

I don't know napkin calculation, english is not my first language so my expression is not that good.

Being an inventor alone is far greater than anything an engineer like you can be, in both technology and financial achievement. Being a great inventor, who can influence the world, change how battlefield is fought, is not even in your dream, loser

Firstly, what part of 'behave yourself' do you not understand?

 

Secondly, I work with inventors every day. Some (usually those who are also scientists or engineers) produce amazing improvements to cutting-edge technology. Others are fuckwits with overblown opinions of themselves who waste a lot of time and money trying to protect their insipid creations.

 

Saying that you're an inventor and entrepreneur means nothing. What you invent and make/sell is the important part. So put up or shut up.

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6 hours ago, lemd said:

Better my ass, I am an inventor, enterpreneur, what did you do your whole life on my caliber?

I don't know napkin calculation, english is not my first language so my expression is not that good.

Being an inventor alone is far greater than anything an engineer like you can be, in both technology and financial achievement. Being a great inventor, who can influence the world, change how battlefield is fought, is not even in your dream, loser

Well somebody needs to take a big dose of "shut the fuck up!". 

Inventor and Enterpreneur my ass! If you lack even the manners of a 5 year old child, you need to get your priorities straight. 

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For shiggles I threw together a few rods in solidworks and used the SimulationXpress default settings to judge stiffness. 3 rods: one smooth (10mm r 800mm l); one ribbed (11.5mm r with a 1.5x1.5mm revolved cut every 3mm, so just like the original rod with a series of 1.5mm square rings with 1.5mm between each, 800mm l); and one with a thread (11.5mm total diameter, with a 3mm pitch square thread cut 1.5mm deep - so like the second rod only with threads instead of a series of grooves).

All were fixed at one face and had 20N applied parallel to the other face, material assumed to be tool steel. Results were:

1) Solidworks hates threads. It took 1s for the smooth rod, 22s for the ribbed rod and half and hour for the threaded rod

2) Unsurprisingly, ribs or threads do improve stiffness. Max displacement was 2.139mm for the smooth rod, 2.001mm for the ribbed rod and 1.994 for the threaded rod. This is an improvement, but I'm not sure if it corresponds to a 46% improvement in second moment of area

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On 2/5/2017 at 7:43 AM, lemd said:

Better my ass, I am an inventor, enterpreneur, what did you do your whole life on my caliber?

I don't know napkin calculation, english is not my first language so my expression is not that good.

Being an inventor alone is far greater than anything an engineer like you can be, in both technology and financial achievement. Being a great inventor, who can influence the world, change how battlefield is fought, is not even in your dream, loser

I design tank ammunition.

 

Now get the fuck out.

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On 2/4/2017 at 11:43 PM, lemd said:

Better my ass, I am an inventor, enterpreneur, what did you do your whole life on my caliber?

I don't know napkin calculation, english is not my first language so my expression is not that good.

Being an inventor alone is far greater than anything an engineer like you can be, in both technology and financial achievement. Being a great inventor, who can influence the world, change how battlefield is fought, is not even in your dream, loser

 

Ok, you've won the exceptional prize of drawing my attention for being a particularly noteworthy bag of flaming shit, let me honor you on this occasion by shitfucking you back to the stone age real fast. (Which is where I imagine your level of actual technical prowess sits.)

You come here with 2 of the most mind agonizingly retarded posts I've ever seen, spaced out months apart no less, the first showing you can't read, the second showing that, rather the cutting your losses and quitting while you're behind, you just came to prove that you really are an exceptionally dumb motherfucker making grandoise claims of shit you've never been and never will be to try and save face, not realizing this actually just made you look like a fucking scumbag piece of shit.

You speak of "financial achievement", see, unlike you, this forum knows of my finances because I've shown them pieces of it, and I would bet millions it's higher then yours, you're fucking nothing, you're a goddamn pretender who wants to feel important but won't ever amount to shit, but at least you can project that on others.

Being and inventor that "can change the world and how the battlefield is fought", ok, humor us, show us your amazing inventions you sloth brained inbred shit, actually, don't, no one here believes you and we all know you're full of shit pretending to be someone you're not, you're goddamn dumpster trash, you'd have less chance of influencing battles or technological advancements then fucking Mike Sparks and Blacktail, infact, they're sadly smarter then you are, your brain cavity is filled with nothing but rotted pulp that's been fucked into nothing by the dick of your ego and delusions of grandeur.

Now then, seeing as how you made all of 2 posts and proved you're completely, utterly useless, kindly get the fuck out of here, I am fucking Lion of Judah, I carry in me blood of fucking kings, I am the doombringer and thrower in the fucking dumpster of shitstain failed abortions like you and the bringer of light the the darkness of the semen coated walls of the places your type thrive, the greatest honor in life would be you getting hit by a bus and me fucking your corpse and using the blood to paint my face and using it to purge other inbred shit eaters like you in a witch hunting ritual to better the world.

In short, fuck you you pretender projecting piece of shit, Bronez has proven himself here, you've proven to be a likely sub 10 IQ dumpster tier goatfucker who will never actually amount to anything.

Now get the fuck off this forum and never return, you anime body pillow fucking cum stained spastic retard.

 

 

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3 hours ago, sevich said:

wouldn't it increase stiffness width-wise, but not length-wise?

I'm not sure, what do you mean?

If we consider a generic cylindrical rod:

=============================    <ascii rod

There are 3 axes that we can consider bending in: along the x axis (left to right); the y axis (up and down); and the z axis (into and out of the screen). Whichever axis we consider the bending in, the forces involved must be oriented in one of the other axes - so for the x axis, any bending forces must be applied in the y or z axes. As the rod is rotationally symmetric, many of these cases look identical:

  • for bending in the x axis, it doesn't matter whether the force is applied in the z or y axis - the result is the same
  • bending in the z axis with force applied in the x axis looks identical to bending in the y axis with force in the x axis (for a shorter rod, think of this case as breaking a cylindrical tablet in half - without the scored line, the case is the same when you rotate the tablet about the x axis)
  • bending in the y axis with force in the z axis is identical to bending in the z axis with force in the y axis, but this is a weird case anyway so ignore it

In the simulation, the rod was bent in the x axis, which corresponds to fixing the left hand end of the generic rod above while applying a load downwards to the right hand end.

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8 hours ago, Xlucine said:

 

In the simulation, the rod was bent in the x axis, which corresponds to fixing the left hand end of the generic rod above while applying a load downwards to the right hand end.

Just to make sure, is this the same principle behind why bird cages are so strong?

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15 hours ago, sevich said:

Just to make sure, is this the same principle behind why bird cages are so strong?

It's related. There's a mathematical measure of how well a cross-section will resist bending, which I was taught as second moment of area (although bronez calls it area moment of inertia earlier, same difference). Using the same axes as my earlier post, when bending in the x axis with a force in the y axis you double integrate y^2 over the y axis and the z axis. This, combined with the stiffness of the material and the bending moment at that particular point, gives the curvature; and integrating the curvature twice along the x axis dives you the displacement (the first integral gives the angle the beam is at, the second the displacement). So for a rod without a constant cross section, the thicker bits have less curvature and the thinner bits have more curvature. The second moment of area scales with the width (in the axis of the bending force) cubed multiplied by the other width, so a wide structure (like a birdcage) is much much stiffer for the same weight as a thin structure (like the wire the cage is made from).

 

In practice, the maths for beams with constant cross-section is fiddly and a pain, and non-constant cross-sections even worse, so everyone hides the maths in a computer FEA model

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On 2/5/2017 at 1:43 AM, lemd said:

Being an inventor alone is far greater than anything an engineer like you can be

Ahahahah you idiot. I'm an engineer, and if I had a nickel for every "inventor" who failed out of high school calculus and thought he just made a fantastic breakthrough, I could retire. Whenever one of you geniuses has an idea you claim is revolutionary, there's a 99% chance it was either tried before or defies the laws of physics and could never work. The remaining 1% is inventions that are actually decent but so hilariously inefficient that you would need an engineer to hammer it into shape to not get laughed out of any investor meeting.

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      Also included with the armament were three unity periscopes for each crewman, a single-plane stabilization system for the main gun, and a gunner/commander cowitnessing system. The turret had two ready racks of five rounds a piece, with additional ammunition stowage planned to be in the floor of the vehicle, and adjacent to the driver.
       
      The turret was cast with 3.5-3.6" all around armor, improving to six inches at the front. A large, wide mantlet/gun shield of 6" thick was provided, partially to help balance the gun in its cradle. The turret ring was 74".
      NBC protection was available through a "kit" modification that was distributed to member nations upon request.
       
      Specifications, NATO Medium Tank:
       

       
      Crew: 4
      Dimensions
      Weight: 39.4 t
      Length (Hull): 7.2 m
      Width: 3.4 m
      Height: 3.05 m (without roof MG)
      Armament
      Main armament: 90mm T104E3/M56
      Caliber length: 62
      Tube length: 5.60 m
      Tube life: 500 shot
      Secondary armament: 1 × M1919, M60, MAG, MG3, etc GPMG
      Cannon ammunition: 65
      MG ammunition: 3200
      Elevation: +25/-12
      Penetration with T53 Shot, 10.9 kg at 976 m/s:
      100 m: 22.2 cm
      500 m: 20.0 cm
      1000 m: 17.9 cm
      2000 m: 14.3 cm
      Armor
      Upper Hull: 76.2 mm / 30 °
      Lower Hull: 76.2 mm / 45 °
      Rear Hull: 38.1 mm / 90 °
      Hull Roof: 25.4 mm
      Hull Floor: 25.4 mm
      Turret Mantlet: 152.4 mm / 90 °
      Turret Front: 152.4 mm / 90 °
      Rear Turret: 90 mm / 90 °
      Turret Roof: 50.8 mm
      Mobility
      Engine: Depends on variant, often AV-1790 w/ CD-850 transmission or Meteor with Merrit-Brown Z.51.R transmission. Variant with Ford GAA and syncromesh transmission also trialled.
      Displacement: Depends on variant
      Gears (F / R): Depends on variant
      Power to weight ratio: Depends on variant
      Top speed: Depends on variant
      Suspension: Depends on variant
      Fuel storage: Depends on variant
      Range: Depends on variant
      Track width: Depends on variant
       
       
    • By Mighty_Zuk
      Here we will discuss all topics related to the LAND program, including, but not limited to, LAND 400 which is the flagship project of the entire program.
    • By Akula_941
      12 March fresh new video here
      just so many of good footage,praise the IRINN.IR

      so,Karrar MBT aka T-90MS mod 2017 Iranian limited Edition 2.0
      Has finally have a bit long TV report,and what is this?

      when i see this ‘barrel protective case’ thing,the only thing in my mind is
      "NO,T-72I4! It's him! He is Back!"


      but after watch the video i pretty sure it's nothing but reference ~
      first noticed difference is the ERA kit

      Karrar 'ERA kit is smaller, have 6 plate on each slide front
      compare to T-90MS 's 4 larger size Relikt ERA

      the thickness of the ERA are pretty close so i guess it's just the smaller new Relikt variant

      RCWS/Commander panoramic sight Station
      huge muzzle brake but it seems just a 7.62mm RCWS,but looks cool

      also the sight itself looks a cheaper product compare to T-90MS


      Digital map,commanding system and Vehicle information Display 
      this is pretty good, Karrar may have the best digital equipment in all Iranian tanks,not even Zulfiqar-3

      normal vision channal of the commander sight
       
      for the gunner,i noticed something interesting

      now this is something new, the Karrar have a whole new gunner sight,so obviously the new gunner sighting system is not simply rip-off from russian
      but the really interesting thing is, it keeps the 1K13,which compare to T-90MS removed 1A45 completely and replaced by Sosna-U and a back up sight

      why is this?  @Lightning think, that Iran hasn't prepare or able to create their own laser guide coding equipment,if they want to use 9K120 ATGM system,they need keep the 1K13 for laser coding
      which i found is a high possibility that could be true

      karrar‘s gunner displayer compare to T-90MS

       
      let's expect more information of this tank in the future

       
       
    • By Collimatrix
      PELE (Penetrator with Enhanced Lateral Effectiveness) rounds are a new type of ordnance developed by Rheinmetall in the late nineties and early two thousands.
       
      As the patent shows, they are similar in outward appearance to traditional long-rod penetrators, but are different in cross section:
       

       
      The basic principle of a PELE is that the outer walls of the penetrator are made of a denser material than the core.  At the extremely high velocities that the penetrator strikes the target, density (rather than material strength) is one of the most important factors in determining penetration.  So the outer walls are able to penetrate the target, but the inner core is not.  The outer walls of the penetrator continue moving forward, which compresses the inner core.  This presentation from ATK has a helpful diagram:
       

       
      As this Rheinmetall presentation shows, this gives much greater behind armor effect than a traditional long rod penetrator:
       

       
      This new ammunition is available both in large-caliber and autocannon calibers.
       
      Compared to traditional high explosive rounds, PELE rounds have the advantage that there is no explosive material in the penetrator.  This means that there is no UXO risk at training ranges.  Additionally, a tank with APFSDS and PELE ammunition types would be able to tackle most target types.  If the ammunition were two-piece, then the inert APFSDS and PELE penetrators could be stored in the turret while the propellant charges could be stored separately in isolation.  Britain's chieftain MBT used an ammunition stowage scheme like this, keeping inert APDS projectiles in the turret and propellant bags underneath the turret ring in wet ammunition containers.  An ammunition stowage scheme like this would have the advantages of isolated ammunition stowage, but would require a less bulky isolated section of the tank, which often adds to the silhouette of the vehicle (e.g. abrams' enormous turret bustle).
       
      The biggest disadvantage of PELE compared to traditional high explosive rounds is that the rounds do not fragment unless they hit something hard.  As the presentations above show, the 120mm rounds will produce considerable fragmentation patterns after hitting something as light as 10mm of sheet metal, but they still need to hit something.  So airburst or proximity fused options are out.
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