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20 hours ago, Mighty_Zuk said:

Yep. You could extend such a design to accommodate a couple more rounds, but it's made for the Abrams turret, which is already pretty wide.

cLKp6sT.png

My issue is the huge empty space on each side of the gun, shouldn't it be possible to fit two drums on each side?

 

Roughly this size:
aaSuj1N.jpg

 

 

2 hours ago, Lord_James said:

 

Why not have a bustle loader like the Leclerc or T-84 Yatagan? Would allow for a roof mounted turret and a long bustle over the crew capsule. 

 

 

Also, first post from a ~2 month lurker. Hey Xoon, Alzoc, Ramlaen and Zuk :) 

Welcome to the forum James!

 

Zuk here used the Meggit autoloader as a example because the Leclerc autoloader only fits around 16 rounds, might be 21, but still way to low. 

 

 

2 hours ago, Alzoc said:

 

Nice to see you as well.

I also saw that even Tovarish is starting to think about joining as well

This forum is growing fast.

 

Nice to hear that Tovarish might be coming over.

 

 

2 hours ago, Lord_James said:

 

The problem I see with that loader is the shells are stored in reverse, which would require another assembly to flip the shell over, which would reduce the load time. Though, the gears in my head are spinning, and I wonder if something like a hybrid of that Meggitt loader (turned so the shells face forward) and an oscillating turret could happen; would have a great RoF while still retaining the 34 round rack [see AMX-50 Surbaisse autoloader]. 

 

 

PS. I also adhere to the design philosophy of the front mounted engine and rear crew compartment, which (managed properly) can provide additional crew survivability, IMO the most important part of a tank. 

A oscillating turret are quite tall, or has to have less gun depression/elevation.

 

I think a cleft turret would be a better bet.

strv2000_data.jpg

 

 

 

The Swedish tested several turret layouts and found the cleft turret to be the best, here's a comparison of a conventional turret, a autoloaded conventional turret, and a cleft turret. 

strv2000-modeller.jpg

 

 

Of course the overhead turret will turn out taller than on the picture, but it cuts out over a meter of length from the oscillating part, giving it much better elevation.

 

 

Here is a view of how the turret looks while depressed, though probably exaggerated:
strv_2000_t140_40__max_depression__by_ar

 

 

15 minutes ago, Lord_James said:

 

Couldn’t you (theoretically) place that extra ammo in a wet rack? I mean, if fuel could become an issue, why not just add that extra capacity by placing a fuel tank around the ammo? I’m not saying remove the blow out panels, but integrate the wet storage into the safe storage. 

Good point, I do not think that a fuel tank/ammo rack combination would be a problem with a blow out panel. Same with wet racks. Though, I am pretty sure you can't use fuel as the "wet" part in a wet rack.

 

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On 19.1.2018 at 4:54 PM, Mighty_Zuk said:

If you guys don't mind, I'd like to revive an old debate about which layout would be the best for the next generation of MBTs.

 

What I had in mind is an MBT that necessarily places its crew, inside a protected capsule, at the very rear of the vehicle.

What this gives them is a rear access door through which they can escape, rather than try to escape through the top hatches or a floor escape hatch. This, in order to both improve mine protection and allow more comfortable operation when the tank is stationed in a ready hull-down position.

What's left of this is to locate the powerpack and the turret. Since a forward placed turret may be problematic to handle in almost any type of terrain or combat area, it'd be best to put the engine at the front and the turret in the middle.

The batteries for the engine would be located all across a double V floor (between the two floors) to save space and keep the engine bay as small as possible.

 

@Xoon, you're the top authority on making neat sketches. What's your take on this?

Got a simple hull drawing here:
35W0fLf.png

 

Going to make the turret later, got to improve my skills with Solid Edge. 

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5 hours ago, Mighty_Zuk said:

The QuickDraw autoloader that Xoon showed here is supposed to be in the bustle.

 

And hello there James. Nice to see you migrated.

 

Nope, that's not FastDraw. Meggitt's horizontal autoloader is actually more akin to the XM91 that was supposed to be included in the CATTB. GDLS' FastDraw had two horizontal bustle carousels, each equipped with its own actuator (the RALS or Robotic AutoLoader System) in order to extract and align the round with the breech.

 

Just for reference, the vertical autoloader carousel in the TTB could handle 44 120mm rounds, whereas FastDraw could take 36 (2 cylinders containing 18 rounds each, with what looks like loading ports built in the turret sides). A hypothetical FMBT autoloader (see figure 5) could have 40 rounds in a conical vertical carousel, with 23 reserve rounds in a rear compartment (though IIRC that was a paper tank designed for some DARPA study and not an Abrams successor project meant to produce an actual vehicle).

9hGziXh.jpg

---
NmzWTyz.png

---
5bDNMnj.png

---

L84SERi.png

---
03yjBjv.png

 


FastDraw:

ITEYuO1.png

 

The XM91 (note: 140mm ammo, not 120mm):

S92dokW.png

 

Meggitt's autoloader:

6nL9x2B.jpg

 

PyRJrUL.jpg

 

Apologies for the wall-o'-pictures.

 

 

Also, Tovarish here? My god...that means...the memes are coming! *dons flak vest and jumps into a foxhole*

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4 hours ago, Xoon said:

 

A oscillating turret are quite tall, or has to have less gun depression/elevation.

 

I think a cleft turret would be a better bet.

strv2000_data.jpg

 

 

 

The Swedish tested several turret layouts and found the cleft turret to be the best, here's a comparison of a conventional turret, a autoloaded conventional turret, and a cleft turret. 

strv2000-modeller.jpg

 

Oh, (from what I understand) like the T92, Ob'yekt 490A Buntar, and Stryker M1128. My thoughts were to maximize RoF, as the cleft turret has to reset the gun to reload, though if it means this fantasy tank can have the Buntar's awesome looking turret, I'm all in. :) 

 

Quote

Though, I am pretty sure you can't use fuel as the "wet" part in a wet rack.

I didn't know what else to call it, other than a "fuel tank rack". 

 

 

On a separate note; troop carrying MBTs: 

 

BTMP-84 

BTMP-84

 

BMT-72 

Related image

 

Made by those krazy Kharkovites. Discuss. 

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1)The fact that a turret has to reset, in itself lowers the actual RoF (not theoretical one) as it takes time to actually reset and then lay the gun on target again, even if it doesn't require any gunner's input.

 

How much is resetting? 1 second? Then laying takes about 2-3 secs. Make it 4-5 if the whole thing is designed so that the gunner loses his sight over the target during the loading sequence.

 

2)Tovarish's memes were stale anyway.

 

3)BTMP concepts were interesting but impractical in any possible way. Too low troop capacity, exit only from top, slow dismounting, hatches can actually be blocked, and the thing cannot give the infantry any proper support at the dismount stage at least on the level a proper IFV could.

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1 hour ago, Mighty_Zuk said:

1)The fact that a turret has to reset, in itself lowers the actual RoF (not theoretical one) as it takes time to actually reset and then lay the gun on target again, even if it doesn't require any gunner's input.

 

How much is resetting? 1 second? Then laying takes about 2-3 secs. Make it 4-5 if the whole thing is designed so that the gunner loses his sight over the target during the loading sequence.

 

 

The gunner's primary sight on a modern tank isn't attached to the gun tube.  It's independent, stabilized, and stays on target regardless of what the gun is doing.

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8 hours ago, Lord_James said:

 

Oh, (from what I understand) like the T92, Ob'yekt 490A Buntar, and Stryker M1128. My thoughts were to maximize RoF, as the cleft turret has to reset the gun to reload, though if it means this fantasy tank can have the Buntar's awesome looking turret, I'm all in. :) 

Like Zuk pointed out, the gun needs to be laid, which takes time. And I am also concerned about the barrel overheating. 

 

Though,  a ready rack drum could be used for 5-10 rounds.

 

8 hours ago, Lord_James said:

On a separate note; troop carrying MBTs: 

 

BTMP-84 

BTMP-84

 

BMT-72 

Related image

 

Made by those krazy Kharkovites. Discuss. 

Weird project by the Ukrainians, I find the Merkava more practical to be honest. 

 

1 hour ago, Collimatrix said:

 

The gunner's primary sight on a modern tank isn't attached to the gun tube.  It's independent, stabilized, and stays on target regardless of what the gun is doing.

Isn't the LeClerc's gun mechanically linked to the gunners sight?

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1 minute ago, Xoon said:

Isn't the Leclerc's gun mechanically linked to the gunners sight?

 

It is, and AFAIK it was done to eliminate any alignment issue with the gun.

The designers went to great length to have an extremely stable gun so why not link the gunner sight to it? (Should be stable as well right?)

 

The problem it cause is obviously the infamous gunner sight weakspot.

 

Nowadays electronics and informatics have come a long way (Remember that when the Leclerc came out, having a tank fully digitalized and not relying on analogical devices at all was kinda rare) so I doubt they would bother with all those mechanical parts if they had to remake it.

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1 minute ago, Xoon said:

Isn't the LeClerc's gun mechanically linked to the gunners sight?

 

I don't believe so, not in the way you're thinking.

 

The way modern fire-on-the-move fire control works is that the gun and gunsight are independently stabilized.  It's fairly feasible to stabilize a little piece of glass or mirror inside a gunsight so that it stays pointed at the target regardless of whatever sort of bouncing or pitching the tank is doing.  It is not particularly feasible to keep the gun tube pointed at the target all the time, at least, not pointed at the target so precisely that it would actually score a hit if it were to be fired at any given moment.

 

The gun tube simply has too much inertia and moment of inertia to be stabilized that precisely.  It is, after all, a multi-ton tube of steel.  So what is happening is that the gun tube is sort of wandering around as the gun hydraulics strain to keep it stabilized.  It will eventually pass through a point where it is pointed right where it needs to be pointed in order to score a hit, but most of the time it is only floating nearby that point.

 

So what the fire control system does is it figures out a fire solution for whatever target the sight is looking at and has lased, and then waits for the gun tube to come into alignment with the sight.

 

The trick is making sure that the fire control system knows the spatial relationship between the gun tube and the gun sight.  That's why there's a muzzle reference system, but even with that in place the system needs frequent re-calibration.

 

So yes, the primary sight on the Leclerc has a linkage of some sort to the gun tube, causing an aggravating weak point on the right side of the turret, but I suspect that this is an engineering shortcut to help ensure that the fire control computer knows the spatial relationship between the gun tube and the gunsight.  I would be very surprised if the gunner's crosshairs actually budge when the Leclerc's gun elevates while reloading.  That would be stupid and archaic.

 

The one I'm not sure on is the Chally 2.

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1 hour ago, Collimatrix said:

 

The gunner's primary sight on a modern tank isn't attached to the gun tube.  It's independent, stabilized, and stays on target regardless of what the gun is doing.

True, it doesnt have to be slaved. That's an error on my part. Still, laying the gun itself even if youre already pointing on the target takes time.

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Just now, Mighty_Zuk said:

True, it doesnt have to be slaved. That's an error on my part. Still, laying the gun itself even if youre already pointing on the target takes time.

 

Watch footage of a Leo 2 firing.  On most tanks, even those with manual loading, the gun automatically elevates for reloading.

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1 hour ago, Collimatrix said:

The gun tube simply has too much inertia and moment of inertia to be stabilized that precisely.  It is, after all, a multi-ton tube of steel.  So what is happening is that the gun tube is sort of wandering around as the gun hydraulics strain to keep it stabilized.  It will eventually pass through a point where it is pointed right where it needs to be pointed in order to score a hit, but most of the time it is only floating nearby that point.

 

I remember reading that they payed a particular attention on mass balance around the trunnion for the Leclerc's gun, so that the strain on the electric drive of the gun would be as limited as possible.

Spoiler

 

 

Don't know the final performance level they reached, but Nexter/GIAT commonly marketed the Leclerc as the only tank with a true fire on the move capability (describing the M1, Leo 2 and Challenger 2 as tanks that have merely acquired this capacity at limited speed and only in the frontal arc).

 

When reading on the history of it's development one have the really distinct feeling that they went full retarted on having the best stabilization possible.

The initial aluminum tracks that had awful service life were chosen for their light weight but mostly because they generated less vibrations, for example.

 

Dunno if the M1, Challenger 2 and Leo 2 still use an hydraulic drive for their guns or if their most recent versions switched to electric.

 

1 hour ago, Collimatrix said:

So yes, the primary sight on the Leclerc has a linkage of some sort to the gun tube, causing an aggravating weak point on the right side of the turret, but I suspect that this is an engineering shortcut to help ensure that the fire control computer knows the spatial relationship between the gun tube and the gunsight.  I would be very surprised if the gunner's crosshairs actually budge when the Leclerc's gun elevates while reloading.  That would be stupid and archaic.

 

A sort of mechanical arm that would measure the angular difference?

Well that's a question for a crewman for once. Does the gunner lose the target when the gun is reloading?

@Serge Aren't you the one who knows an ex Leclerc TC?

Or was it @Laviduce?

 

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12 hours ago, Renegade334 said:

...

Apologies for the wall-o'-pictures.

...

There is spoiler button in post editor (an eye icon).

 

10 hours ago, Lord_James said:

BTMP-84 

Spoiler

BTMP-84

 

BMT-72 

 

Spoiler

Related image

 

 

Made by those krazy Kharkovites. Discuss. 

   Throw away troops, put all ammo that are inside of the tank but not loaded to autoloader in that troop compartment, add blow out panels. If possible - add mechanical loader for an autoloader, Object 477 Boxer/Molot - style, so you can autload your autoloader while autoloading main gun.

 

   You also can put T-72-120 turret on top, so you will have 3 autoloaders in 1 tank

880459_900.jpg

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5 hours ago, Collimatrix said:

 

I don't believe so, not in the way you're thinking.

 

The way modern fire-on-the-move fire control works is that the gun and gunsight are independently stabilized.  It's fairly feasible to stabilize a little piece of glass or mirror inside a gunsight so that it stays pointed at the target regardless of whatever sort of bouncing or pitching the tank is doing.  It is not particularly feasible to keep the gun tube pointed at the target all the time, at least, not pointed at the target so precisely that it would actually score a hit if it were to be fired at any given moment.

 

The gun tube simply has too much inertia and moment of inertia to be stabilized that precisely.  It is, after all, a multi-ton tube of steel.  So what is happening is that the gun tube is sort of wandering around as the gun hydraulics strain to keep it stabilized.  It will eventually pass through a point where it is pointed right where it needs to be pointed in order to score a hit, but most of the time it is only floating nearby that point.

 

So what the fire control system does is it figures out a fire solution for whatever target the sight is looking at and has lased, and then waits for the gun tube to come into alignment with the sight.

 

The trick is making sure that the fire control system knows the spatial relationship between the gun tube and the gun sight.  That's why there's a muzzle reference system, but even with that in place the system needs frequent re-calibration.

 

So yes, the primary sight on the Leclerc has a linkage of some sort to the gun tube, causing an aggravating weak point on the right side of the turret, but I suspect that this is an engineering shortcut to help ensure that the fire control computer knows the spatial relationship between the gun tube and the gunsight.  I would be very surprised if the gunner's crosshairs actually budge when the Leclerc's gun elevates while reloading.  That would be stupid and archaic.

 

The one I'm not sure on is the Chally 2.

Would a high speed puls counter connected to the trunnion be good enough? Or would the barrel flex too much?

 

 

Also, the frenchies made (almost) Zuk's wet dream:
0068Ayuagy1fc6cc044tej31kw16ou0z.jpg

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6 hours ago, Collimatrix said:

 

Watch footage of a Leo 2 firing.  On most tanks, even those with manual loading, the gun automatically elevates for reloading.

That compensates for the laying time by reducing the time it takes the loader to complete his sequence. With an added bonus of less strain on his back of course.

In tanks with autoloaders this isn't really an issue.

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On the mass balance topic, here's a citation of a book I (and probably other French speaking members) own.

Even if you don't speak French it's quite a nice book to have with plenty of pictures (all those pictures of the various early EPC concept comes from here), though you have the impression that nobody ever proofread it (screw grammar and the orthograph^^).

 

P58:

 

Comme pour la fonction mobilité, une mécanique de haute technologie est requise pour la fonction feu. Celle-ci est entièrement conçue pour faire du tir en roulant le mode normal d'engagement des cibles.

La précision de la stabilisation est donc au cœur des performances du système. Stabiliser un objet dans l'espace (en l’occurrence la tourelle et son canon) est un défi technique qui requiert de la part de l'ingénieur en mécanique le respect des trois règles d'or:

 

-La recherche des équilibres ;

-Le contrôle des élasticités et des déformations dynamiques ;

-La chasse au jeu entre les pièces.

 

Ces équilibres sont obtenus par conception du canon de 120mm et de la tourelle dont les centres de gravité sont respectivement situés sur les axes de rotation site et gisement.

 

Canon et tourelle sont mis en mouvement à l'aide de moteurs électriques transmettant leur puissance à des boîtes mécaniques de pointage dont les élasticité sont contrôlées en permanence grâce à un montage utilisant des barres de torsion.

Enfin des roulements à billes sans jeu assistent le mouvement du canon dans l'axe vertical.

Sans ces technologies mécaniques particulières, la meilleure électronique du monde ne saurait conserver le canon en direction de la cible sans une débauche de puissance peu compatible avec les contraintes d'emport dans une tourelle.

 

Google trad doesn't make too bad of a job translating it but the main points are:

 

-The gun center of gravity lay on the level of the trunnion

-The turret center of gravity is on the axis of rotation of said turret

-The elasticity of the mechanical parts driving the gun and the turret are monitered in real time using torsion bars (don't know exactly how)

-Ball bearings with minimal backlash (and same apply for most moving parts) are used.

-No hydraulics, everything is electrically driven.

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11 hours ago, Alzoc said:

 

I remember reading that they payed a particular attention on mass balance around the trunnion for the Leclerc's gun, so that the strain on the electric drive of the gun would be as limited as possible.

Yes.

The Leclerc MBT barrel is very rearward compared the manualy loaded turret. This way, artillery is naturally balanced. 

 

Quote

Don't know the final performance level they reached, but Nexter/GIAT commonly marketed the Leclerc as the only tank with a true fire on the move capability (describing the M1, Leo 2 and Challenger 2 as tanks that have merely acquired this capacity at limited speed and only in the frontal arc).

Yes.

Leclerc MBT was the first tank designed to achieve fire on the move at hight speed. Firing off road at 40km/h to a mobile target is basic.

Maybe Type-10 and K2 are better today. Maybe. 

 

Quote

When reading on the history of it's development one have the really distinct feeling that they went full retarted on having the best stabilization possible.

The initial aluminum tracks that had awful service life were chosen for their light weight but mostly because they generated less vibrations, for example.

Yes. 

Aluminium tracks can’t last as long as classical steel ones. They were found too much expensive to support for peace time. 

 

Quote

 

A sort of mechanical arm that would measure the angular difference?

You have such a mechanical link. I don’t know the exact purpose. 

 

Quote

Well that's a question for a crewman for once. Does the gunner lose the target when the gun is reloading?

@Serge Aren't you the one who knows an ex Leclerc TC?

Or was it @Laviduce?

 

I was AMX-10RC tank commander. I never served with Leclerc MBT. So, I can’t help for very detailed data. 

In France, you have Leclerc, Darklabor, Totochez, Rescator. They are not bullshiting. 

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1 hour ago, Serge said:

-snip-

What did you dislike about the AMX-10RC, or armored vehicles in general? 
Everything counts, even lack of space for snacks for that matter. 

 

 

 

Also, could a modified version of this turret be used as a modular turret for medium weight AFVs?
0068Ayuagy1fc6cc044tej31kw16ou0z.jpg

 

 

It does appear to be almost completely overhead, and by hanging the bustle over the rear we get around the issue elevation.

 

I could imagine a modernized and modified version of this fitted on IFV chassis for fire support missions. 

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19 minutes ago, Xoon said:

It does appear to be almost completely overhead, and by hanging the bustle over the rear we get around the issue elevation.

 

It isn't.

It's a low profile turret.

 

Also note that the ammo containers are lowered, hidden behind the hull, most of the time.

They are only raised when reloading the primary drum.

 

(Sorry for the quality of the pic, lighting isn't exactly good in my flat)

Wyw9atU.jpg

c2a0af58e19ef91f9b4d00ae3e3d6659

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15 hours ago, Mighty_Zuk said:

 

3)BTMP concepts were interesting but impractical in any possible way. Too low troop capacity, exit only from top, slow dismounting, hatches can actually be blocked, and the thing cannot give the infantry any proper support at the dismount stage at least on the level a proper IFV could.

 

The BMT-72 is the only one with roof hatches only, the BTMP-84 has a rear hatch like the Achzarit: 

http://www.military-today.com/tanks/btmp_84_images.htm

Though it could be semi useful for pier vs. pier wars as you can carry infantry within the heavy armor of the MBT and have those infantry right there instead of having a less armored (and typically slower) APC/IFV following. Idk, I might be trying to justify others ignorance/idiocy again. 

 

 

On a side note: how do you post something directly from your computer? I have a (mediocre) paint drawing of a change to the Leo 2 but I don't know how to post it :( What am I missing? 

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11 minutes ago, Lord_James said:

 

The BMT-72 is the only one with roof hatches only, the BTMP-84 has a rear hatch like the Achzarit: 

http://www.military-today.com/tanks/btmp_84_images.htm

Though it could be semi useful for pier vs. pier wars as you can carry infantry within the heavy armor of the MBT and have those infantry right there instead of having a less armored (and typically slower) APC/IFV following. Idk, I might be trying to justify others ignorance/idiocy again. 

 

 

On a side note: how do you post something directly from your computer? I have a (mediocre) paint drawing of a change to the Leo 2 but I don't know how to post it :( What am I missing? 

Image uploading site, like imagur.

 

 

21 minutes ago, Alzoc said:

 

It isn't.

It's a low profile turret.

 

Also note that the ammo containers are lowered, hidden behind the hull, most of the time.

They are only raised when reloading the primary drum.

 

(Sorry for the quality of the pic, lighting isn't exactly good in my flat)

Wyw9atU.jpg

c2a0af58e19ef91f9b4d00ae3e3d6659

 

Oh well, I guess the French needs their quirks.

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38 minutes ago, Xoon said:

Oh well, I guess the French needs their quirks.

 

The AS 40 is completely overhead however and the concept is actually very close to the T-14:

 

3 Men in the front sitting together, overhead turret with a carousel autoloader and even less armor than the T-14 on the turret.

Basically there was nothing but the gun completely exposed.

 

First mock up on this video:

 

From left to right: AS 40 ; AS 12 ; AS 22 ; AS 21 and I would say TC 3 and TC 2 (rear engine layout)

 

Spoiler

 

 

 

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1nMgOih.png

 

Here you go, I took the transverse engine idea and moved the ammo to the rear (with a blow out panel and armored door) as well as replaced the front ammo rack with a fuel tank to make up for the displaced fuel. I call it the "Leopard 2S" (S for safe). 

 

 

Edit: could also add an inert gas replacement system to the fuel tanks to help reduce fuel fires (I saw some concern about that in the "Western Tank Rumble" thread). 

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      4.     Fuel- Type, volume available, stowage location, estimated range, neat features.

      5.     Other neat features in the engine bay.

      6.     Suspension- Type, Travel, ground clearance, neat features.

      Survivability:

      1.     Link to Appendix 1 - RFP spreadsheet, colored to reflect achieved performance.

      2.     Link to Appendix 2- armor array details.

      3.     Non-specified survivability features and other neat tricks- low profile, gun depression, instant smoke, cunning internal arrangement, and the like.

      Firepower:

      A.    Weapons:

      1.     Link to Appendix 1- RFP spreadsheet, colored to reflect achieved performance.

      2.     Main Weapon-

      a.      Type

      b.      Caliber

      c.      ammunition types and performance (short)

      d.     Ammo stowage arrangement- numbers ready and total, features.

      e.      FCS- relevant systems, relevant sights for operating the weapon and so on.

      f.      Neat features.

      3.     Secondary weapon- Similar format to primary. Tertiary and further weapons- likewise.

      4.     Link to Appendix 3- Weapon system magic. This is where you explain how all the special tricks related to the armament that aren’t obviously available using Soviet 1961 tech work, and expand to your heart’s content on extimated performance and how these estimates were reached.

      B.    Optics:

      1.     Primary gunsight- type, associated trickery.

      2.     Likewise for any and all other optics systems installed, in no particular order.

      C.    FCS:

      1.     List of component systems, their purpose and the basic system architecture.

      2.     Link to Appendix 3- weapon system magic, if you have long explanations about the workings of the system.

      Fightability:

      1.     List vehicle features which improve its fightability and useability.

      Additonal Features:

      Feel free to list more features as you see fit, in more categories.

      Free expression zone: Let out your inner Thetan to fully impress the world with the fruit of your labor. Kindly spoiler this section if it’s very long.


       Example for filling in Appendix 1
    • By N-L-M
      Restricted: for Operating Thetan Eyes Only

      By order of Her Gracious and Serene Majesty Queen Diane Feinstein the VIII

      The Dianetic People’s Republic of California

      Anno Domini 2250

      SUBJ: RFP for new battle tank

      1.      Background.
      As part of the War of 2248 against the Perfidious Cascadians, great deficiencies were discovered in the Heavy tank DF-1. As detailed in report [REDACTED], the DF-1 was quite simply no match for the advanced weaponry developed in secret by the Cascadian entity. Likewise, the DF-1 has fared poorly in the fighting against the heretical Mormonhideen, who have developed many improvised weapons capable of defeating the armor on this vehicle, as detailed in report [REDACTED]. The Extended War on the Eastern Front has stalled for want of sufficient survivable firepower to push back the Mormon menace beyond the Colorado River south of the Vegas Crater.
      The design team responsible for the abject failure that was the DF-1 have been liquidated, which however has not solved the deficiencies of the existing vehicle in service. Therefore, a new vehicle is required, to meet the requirements of the People’s Auditory Forces to keep the dream of our lord and prophet alive.


       
      Over the past decade, the following threats have presented themselves:

      A.      The Cascadian M-2239 “Norman” MBT and M-8 light tank

      Despite being approximately the same size, these 2 vehicles seem to share no common components, not even the primary armament! Curiously, it appears that the lone 120mm SPG specimen recovered shares design features with the M-8, despite being made out of steel and not aluminum like the light tank. (based on captured specimens from the battle of Crater Lake, detailed in report [REDACTED]).
      Both tanks are armed with high velocity guns.

      B.      The Cascadian BGM-1A/1B/1C/1D ATGM

      Fitted on a limited number of tank destroyers, several attack helicopters, and (to an extent) man-portable, this missile system is the primary Cascadian anti-armor weapon other than their armored forces. Intelligence suggests that a SACLOS version (BGM-1C) is in LRIP, with rumors of a beam-riding version (BGM-1D) being developed.

      Both warheads penetrate approximately 6 cone diameters.

      C.      Deseret tandem ATR-4 series
      Inspired by the Soviet 60/105mm tandem warhead system from the late 80s, the Mormon nation has manufactured a family of 2”/4” tandem HEAT warheads, launched from expendable short-range tube launchers, dedicated AT RRs, and even used as the payload of the JS-1 MCLOS vehicle/man-portable ATGM.
      Both warheads penetrate approximately 5 cone diameters.

      D.      Cascadian HEDP 90mm rocket
      While not a particularly impressive AT weapon, being of only middling diameter and a single shaped charge, the sheer proliferation of this device has rendered it a major threat to tanks, as well as lighter vehicles. This weapon is available in large numbers in Cascadian infantry squads as “pocket artillery”, and there are reports of captured stocks being used by the Mormonhideen.
      Warhead penetrates approximately 4 cone diameters.

      E.      Deseret 40mm AC/ Cascadian 35mm AC
      These autocannon share broadly similar AP performance, and are considered a likely threat for the foreseeable future, on Deseret armored cars, Cascadian tank destroyers, and likely also future IFVs.

      F.      IEDs

      In light of the known resistance of tanks to standard 10kg anti-tank mines, both the Perfidious Cascadians and the Mormonhideen have taken to burying larger anti-tank A2AD weaponry. The Cascadians have doubled up some mines, and the Mormons have regularly buried AT mines 3, 4, and even 5 deep.

      2.      General guidelines:

      A.      Solicitation outline:
      In light of the differing requirements for the 2 theaters of war in which the new vehicle is expected to operate, proposals in the form of a field-replaceable A-kit/B-kit solution will be accepted.

      B.      Requirements definitions:
      The requirements in each field are given in 3 levels- Threshold, Objective, and Ideal.
      Threshold is the minimum requirement to be met; failure to reach this standard may greatly disadvantage any proposal.

      Objective is the threshold to be aspired to; it reflects the desires of the People’s Auditory Forces Armored Branch, which would prefer to see all of them met. At least 70% must be met, with bonus points for any more beyond that.

      Ideal specifications are the maximum of which the armored forces dare not even dream. Bonus points will be given to any design meeting or exceeding these specifications.

      C.      All proposals must accommodate the average 1.7m high Californian recruit.

      D.      The order of priorities for the DPRC is as follows:

      a.      Vehicle recoverability.

      b.      Continued fightability.

      c.       Crew survival.

      E.      Permissible weights:

      a.      No individual field-level removable or installable component may exceed 5 tons.

      b.      Despite the best efforts of the Agriculture Command, Californian recruits cannot be expected to lift weights in excess of 25 kg at any time.

      c.       Total vehicle weight must remain within MLC 120 all-up for transport.

      F.      Overall dimensions:

      a.      Length- essentially unrestricted.

      b.      Width- 4m transport width.

                                                                    i.     No more than 4 components requiring a crane may be removed to meet this requirement.

                                                                   ii.     Any removed components must be stowable on top of the vehicle.

      c.       Height- The vehicle must not exceed 3.5m in height overall.

      G.     Technology available:

      a.      Armor:
      The following armor materials are in full production and available for use. Use of a non-standard armor material requires permission from a SEA ORG judge.
      Structural materials:

                                                                    i.     RHA/CHA

      Basic steel armor, 250 BHN. The reference for all weapon penetration figures, good impact properties, fully weldable. Available in thicknesses up to 150mm (RHA) or 300mm (CHA).
      Density- 7.8 g/cm^3.

                                                                   ii.     Aluminum 5083

      More expensive to work with than RHA per weight, middling impact properties, low thermal limits. Excellent stiffness.

       Fully weldable. Available in thicknesses up to 100mm.
      Mass efficiency vs RHA of 1 vs CE, 0.9 vs KE.
      Thickness efficiency vs RHA of 0.33 vs CE, 0.3 vs KE.
      Density- 2.7 g/cm^3 (approx. 1/3 of steel).

      For structural integrity, the following guidelines are recommended:

      For light vehicles (less than 40 tons), not less than 25mm RHA/45mm Aluminum base structure

      For heavy vehicles (70 tons and above), not less than 45mm RHA/80mm Aluminum base structure.
      Intermediate values for intermediate vehicles may be chosen as seen fit.
      Non-structural passive materials:

                                                                  iii.     HHA

      Steel, approximately 500 BHN through-hardened. Approximately twice as effective as RHA against KE and HEAT on a per-weight basis. Not weldable, middling shock properties. Available in thicknesses up to 25mm.
      Density- 7.8g/cm^3.

                                                                  iv.     Glass textolite

      Mass efficiency vs RHA of 2.2 vs CE, 1.64 vs KE.

      Thickness efficiency vs RHA of 0.52 vs CE, 0.39 vs KE.
      Density- 1.85 g/cm^3 (approximately ¼ of steel).
      Non-structural.

                                                                   v.     Fused silica

      Mass efficiency vs RHA of 3.5 vs CE, 1 vs KE.

      Thickness efficiency vs RHA of 1 vs CE, 0.28 vs KE.
      Density-2.2g/cm^3 (approximately 1/3.5 of steel).
      Non-structural, requires confinement (being in a metal box) to work.

                                                                  vi.     Fuel

      Mass efficiency vs RHA of 1.3 vs CE, 1 vs KE.

      Thickness efficiency vs RHA of 0.14 vs CE, 0.1 vs KE.

      Density-0.82g/cm^3.

                                                                vii.     Assorted stowage/systems

      Mass efficiency vs RHA- 1 vs CE, 0.8 vs KE.

                                                               viii.     Spaced armor

      Requires a face of at least 25mm LOS vs CE, and at least 50mm LOS vs KE.

      Reduces penetration by a factor of 1.1 vs CE or 1.05 vs KE for every 10 cm air gap.
      Spaced armor rules only apply after any standoff surplus to the requirements of a reactive cassette.

      Reactive armor materials:

                                                                  ix.     ERA-light

      A sandwich of 3mm/3mm/3mm steel-explodium-steel.
      Requires mounting brackets of approximately 10-30% cassette weight.

      Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                                   x.     ERA-heavy

      A sandwich of 15mm steel/3mm explodium/9mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                                  xi.     NERA-light

      A sandwich of 6mm steel/6mm rubber/ 6mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

                                                                 xii.     NERA-heavy

      A sandwich of 30mm steel/6m rubber/18mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

      The details of how to calculate armor effectiveness will be detailed in Appendix 1.

      b.      Firepower

                                                                    i.     2A46 equivalent tech- pressure limits, semi-combustible cases, recoil mechanisms and so on are at an equivalent level to that of the USSR in the year 1960.

                                                                   ii.     Limited APFSDS (L:D 15:1)- Spindle sabots or bourelleted sabots, see for example the Soviet BM-20 100mm APFSDS.

                                                                  iii.     Limited tungsten (no more than 100g per shot)

                                                                  iv.     Californian shaped charge technology- 5 CD penetration for high-pressure resistant HEAT, 6 CD for low pressure/ precision formed HEAT.

                                                                   v.     The general issue GPMG for the People’s Auditory Forces is the PKM. The standard HMG is the DShK.

      c.       Mobility

                                                                    i.     Engines tech level:

      1.      MB 838 (830 HP)

      2.      AVDS-1790-5A (908 HP)

      3.      Kharkov 5TD (600 HP)

                                                                   ii.     Power density should be based on the above engines. Dimensions are available online, pay attention to cooling of 1 and 3 (water cooled).

                                                                  iii.     Power output broadly scales with volume, as does weight. Trying to extract more power from the same size may come at the cost of reliability (and in the case of the 5TD, it isn’t all that reliable in the first place).

                                                                  iv.     There is nothing inherently wrong with opposed piston or 2-stroke engines if done right.

      d.      Electronics

                                                                    i.     LRFs- unavailable

                                                                   ii.     Thermals-unavailable

                                                                  iii.     I^2- limited

      3.      Operational Requirements.

      The requirements are detailed in the appended spreadsheet.

      4.      Submission protocols.

      Submission protocols and methods will be established in a follow-on post, nearer to the relevant time.
       
      Appendix 1- armor calculation
      Appendix 2- operational requirements
       
      Good luck, and may Hubbard guide your way to enlightenment!
    • By Collimatrix
      Shortly after Jeeps_Guns_Tanks started his substantial foray into documenting the development and variants of the M4, I joked on teamspeak with Wargaming's The_Warhawk that the next thing he ought to do was a similar post on the T-72.
       
      Haha.  I joke.  I am funny man.
       
      The production history of the T-72 is enormously complicated.  Tens of thousands were produced; it is probably the fourth most produced tank ever after the T-54/55, T-34 and M4 sherman.
       
      For being such an ubiquitous vehicle, it's frustrating to find information in English-language sources on the T-72.  Part of this is residual bad information from the Cold War era when all NATO had to go on were blurry photos from May Day parades:
       

       
      As with Soviet aircraft, NATO could only assign designations to obviously externally different versions of the vehicle.  However, they were not necessarily aware of internal changes, nor were they aware which changes were post-production modifications and which ones were new factory variants of the vehicle.  The NATO designations do not, therefore, necessarily line up with the Soviet designations.  Between different models of T-72 there are large differences in armor protection and fire control systems.  This is why anyone arguing T-72 vs. X has completely missed the point; you need to specify which variant of T-72.  There are large differences between them!
       
      Another issue, and one which remains contentious to this day, is the relation between the T-64, T-72 and T-80 in the Soviet Army lineup.  This article helps explain the political wrangling which led to the logistically bizarre situation of three very similar tanks being in frontline service simultaneously, but the article is extremely biased as it comes from a high-ranking member of the Ural plant that designed and built the T-72.  Soviet tank experts still disagree on this; read this if you have some popcorn handy.  Talking points from the Kharkov side seem to be that T-64 was a more refined, advanced design and that T-72 was cheap filler, while Ural fans tend to hold that T-64 was an unreliable mechanical prima donna and T-72 a mechanically sound, mass-producible design.
       
      So, if anyone would like to help make sense of this vehicle, feel free to post away.  I am particularly interested in:
       
      -What armor arrays the different T-72 variants use.  Diagrams, dates of introduction, and whether the array is factory-produced or a field upgrade of existing armor are pertinent questions.
       
      -Details of the fire control system.  One of the Kharkov talking points is that for most of the time in service, T-64 had a more advanced fire control system than contemporary T-72 variants.  Is this true?  What were the various fire control systems in the T-64 and T-72, and what were there dates of introduction?  I am particularly curious when Soviet tanks got gun-follows-sight FCS.
       
      -Export variants and variants produced outside the Soviet Union.  How do they stack up?  Exactly what variant(s) of T-72 were the Iraqis using in 1991?

      -WTF is up with the T-72's transmission?  How does it steer and why is its reverse speed so pathetically low?
       
       
    • By Sturgeon
      This is the place for flame wars about rifle-caliber MGs versus autocannons for tank coaxial weaponry. First, we have Ensign's blog post about tank machine guns:
       


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