Rheinmetall's New Tank Gun

[Xoon]

I am not sure if you folks noticed:

 

We got two images of the new gun and it shell. It's a 130mm L51 tank gun.

From the looks of it, the new shell is roughly 1200mm high.

 

What concerned me is the size of the shell. It rules out the carousel autoloader in any future western tank with this gun and a unmanned turret, unless you want a tank that makes the T-14 look short. I also wonder if they have the extend the ammunition rack for the old vehicles to make it fit.

 

If this is already posted or something like that, feel free to notify me and delete the post.

 

 

Mvh

Xoon.

[Militarysta]

Notice

[Molota_477]

Wait.. ETC?

[Xoon]

Wait.. ETC?

From what I know, yes, but I don't have any solid sources. 

 

Only real info on the gun has been a random German magazine and a promotional poster.

 

This was published in the European Forum on Ballistics of Projectiles, article "Status and Results of the German R&D Program on ETC Technologies". The LKE II (DM53 prototype) fired from the L55 gun reached a muzzle velocity of 1750 meters per second (mps) at 21° centigrade, whereas a projectile with the same mass, fired from the ETC prototype gun with 110 KJ of electrical energy added, managed to reach a muzzle velocity of 1822 mps and an energy output of 14 MJ.

[Molota_477]

Sounds interesting.

[Xoon]

Sounds interesting.

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.

[Militarysta]

Wait.. ETC?

 

No. It;s not ETC.

 

[Xoon]

No. It;s not ETC.

 

Thanks for debunking that.

[LostCosmonaut]

130mm is an interesting choice, I thought 140mm was traditionally the next step up from 120mm for ~*future*~ NATO tank guns.

[Khand-e]

130mm is an interesting choice, I thought 140mm was traditionally the next step up from 120mm for ~*future*~ NATO tank guns.

 

IS-7/WZ-111 5A best tank of all years.

[Collimatrix]

Object 770 would like to have a word.

 

I wonder what the breech pressure limit is, and also how gigantic the overpressure zone around the muzzle is.

[Mike E]

I am interested in how it will compare with the 2A82-1M -- which itself claims to have 20-25% over the L/55 cannon.

Also, I doubt the new APFSDS's rod will be much longer than 900-950 mm in length as performance begins to decrease eventually.

We will see.

[Collimatrix]

I am interested in how it will compare with the 2A82-1M -- which itself claims to have 20-25% over the L/55 cannon.

Also, I doubt the new APFSDS's rod will be much longer than 900-950 mm in length as performance begins to decrease eventually.

We will see.

 

Could you elaborate on this point?

[Khand-e]

Could you elaborate on this point?

 

Only if you get on TS.

[Collimatrix]

 

This new 130mm looks like it has smaller ammo than the giant 140mm of yore.

[Militarysta]

I am interested in how it will compare with the 2A82-1M -- which itself claims to have 20-25% over the L/55 cannon.

Also, I doubt the new APFSDS's rod will be much longer than 900-950 mm in length as performance begins to decrease eventually.

We will see.

 

1) I would be very cearfull whit sucht statment like this about 20-25% "over Rh120 L-55 gun". Becouse it was about what exatly?

muzzle MJ for sabot and penetrator? MJ for penetrator during fly? or what?  

 

2) Optimum velocity and penetrator  lenght is diffrent for gun systems and ammo 

More or less simmilar lenght have M829A3 penetrator right now:

 

 

 

And here better photo of the new 130mm:

 

[Mike E]

Could you elaborate on this point?

Going off of a report I saw a while back, rods over a certain length, say 1100 mm, begin to become noticeably impractical versus shorter counterparts. Basically, the longer length makes them more fragile and likely to shatter on impact (and against ERA). The solution around the issue is to make the rod thicker, but this dramatically increases weight and reduces its aerodynamic efficiency.

Interestingly enough, this new rod appears no thicker, maybe even thinner, than the 63A1's. Most likely b/c it is a mock up.

@Militarysta

Maximum muzzle energy, IIRC.

[Collimatrix]

Going off of a report I saw a while back, rods over a certain length, say 1100 mm, begin to become noticeably impractical versus shorter counterparts. Basically, the longer length makes them more fragile and likely to shatter on impact (and against ERA). The solution around the issue is to make the rod thicker, but this dramatically increases weight and reduces its aerodynamic efficiency.

Interestingly enough, this new rod appears no thicker, maybe even thinner, than the 63A1's. Most likely b/c it is a mock up.

@Militarysta

Maximum muzzle energy, IIRC.

 

 

On a lot of modern APFSDS designs the length of the projectile is longer than the length of the penetrator per se.  On M829 and related penetrators there's a break-off portion at the front of the projectile which sacrificially shears off to protect the rest of the penetrator in case it whacks into K5 or similar "heavy" ERA:

 

 

On some European APFSDS designs there's a sub-caliber pre-penetrator which pokes a hole in any ERA without initiating it through which the rest of the penetrator follows.

 

So there are reasons to make the projectile really, really long even if the penetrator doesn't get that much longer.

 

Article at defense update.  Not a lot of new information.

[Bronezhilet]

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:

[Collimatrix]

How much bending resistance could that thread add?  It doesn't have that much volume of material in it and doesn't stick that far out from the center of bending.

 

Pretty sure the main purpose of the thread is to provide the sabot grip during acceleration in the tube.

[Bronezhilet]

How much bending resistance could that thread add?  It doesn't have that much volume of material in it and doesn't stick that far out from the center of bending.

 

Pretty sure the main purpose of the thread is to provide the sabot grip during acceleration in the tube.

46%, according to my napkin calculations.

 

if that was the main purpose, they could do with a lot less thread, couldn't they?

[Collimatrix]

46%, according to my napkin calculations.

 

if that was the main purpose, they could do with a lot less thread, couldn't they?

 

I don't think so.  Look at M111 Hetz:

 

 

The grooves for the sabot to engage are simply circular grooves, not a thread, and they go almost the entire length of the dart.

 

The issue, per Ogorkiewicz, is that tungsten and uranium alloys have low sheer strength relative to their inertia.  You have to spread the gripping out over a lot of grooves as a result.  You can get away with smaller gripping surfaces with all-steel penetrators, which have better sheer strength and lower inertia, and also look like finned dildos:

 

[Collimatrix]

More:

 

 

The projectile on the far right is M900 105mm APFSDS, which was phased out of service with the M1A1 and its 120mm M256, long before anyone in the West knew about K5 ERA.

[Bronezhilet]

Did you do any calculations on that, by the way?

[Collimatrix]

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.

 

Even if we account for the slight increase in tensile stress for a given flex load at the edge of a thread and the reduction of stress risers (or at least the re-direction of them to be not perpendicular to the long axis of the rod), I don't see how we can get a situation where the rod would have gotten fucked up by K5 without the thread, but not fucked up with it.

 

Given that very long grooved sections predate knowledge of K5, and are not present on earlier all-steel penetrators, I think we can safely say that the main purpose of the design is to give adequate material for the sabot to hold on to without sheering.  I'm not sure why Rheinmetall and others are using helical threads instead of simple circular ribs on their design.  It may have advantages to manufacture.  But I can't see how it could possibly prove a decisive counter-countermeasure to heavy ERA.