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SUBMISSIONS for Steel Chariot of The Prairie: The Lone Free State's First Battle Tank (2247)


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1 hour ago, Toxn said:

I think it would depend heavily on the terrain. Something I only realised about the Stumpy after the competition is that its MMP is ass, so any kind of swampy terrain would be a nightmare for it. On firm, rolling ground, however, I think it could just sling giant HEAT missiles at the Monolith until something gives out.

 

What is the range of the LUB?

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1 hour ago, Toxn said:

I think it would depend heavily on the terrain. Something I only realised about the Stumpy after the competition is that its MMP is ass, so any kind of swampy terrain would be a nightmare for it. On firm, rolling ground, however, I think it could just sling giant HEAT missiles at the Monolith until something gives out.

 

I notice that most 2247 competitors would probably eat Stumpy alive. Comanche for example has ~530mm RHA pen at 2kyd. Plus Comanche is immune to the 85mm on Stimpy through a generous frontal arc. Kind of funny since Stimpy is supposed to be a later tank.

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4 minutes ago, Sturgeon said:

 

I notice that most 2247 competitors would probably eat Stumpy alive. Comanche for example has ~530mm RHA pen at 2kyd. Plus Comanche is immune to the 85mm on Stimpy through a generous frontal arc. Kind of funny since Stimpy is supposed to be a later tank.

Ja, Stumpy is more or less an armoured brick with a fairly anemic main gun and a very silly meme-missile.

 

It's pretty on brand with how the DPRC was portrayed though - wonky, dysfunctional and grasping for gee-whiz solutions to problems caused by their own dogma. Its configuration is also a pretty predictable outcome given the very stringent restrictions placed on the competitors (most especially the width limitation, ground pressure requirements, side protection requirements against HEAT charges, and gun restrictions).

 

 

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@N-L-M

First, sorry for the units mess up, it must have been annoying convergin to and fro. Thanks for commenting on my piece too.
I have a few clarifications to provide and a few question to the evaluation.

 

the bad:
-Hull structure insufficiently thick for structural reasons

 

Where is it too thin?

 

-armor does not reach required or claimed protection level (side threat, mine threat, frontal protection of powerpack)

 

My claims about the hull for mission kill are indeed wrong, for the crew compartment are right. The distinction between immobilised tank and crew killed was not specified, afaik. Maybe it is a common knowledge?

Bottom is combined 1.25" in two layers. That is too thin for mine protection?

 

-armor does not provide protection against growth threats.

 

What are growth threats?

 

-engine compartment far too small for the desired powerpack.
-attempting to mount a transverse V12 1500HP engine alongside the driver speaks of a lack of spatial reasoning skills.

 

I had MTU 873 (https://www.yumpu.com/en/document/read/5713483/twelve-cylinder-diesel-engine-mb-873-for-heavy-mtu-shop) main block without turbochargers in mind (turbo would have to be relocated). This leaves about 8 inches of space to the side for some sort of connection with a gearbox of the size of Renk HSWL 295. None of the two are 60ies tech so 1000 HP is more realistic and still fulfills the requirements. The side arrangement is known from T-55 so I assumed it would be possible. Coolers are pushed into sponsons to each side, the 4 big black squares. None of this was exactly decided, but likely indeed too small for existing engines.

 

-Use of single pin, unbushed, tracks gives poor track life, particularly in sandy environments, and is therefore unsuitable to long range self-deploying operations. It is difficult to choose a track link less suitable to the operating environment of the LFS, and along with the overlapped and interleaved suspension speaks of blind cargo culting without understanding the tradeoffs involved.

 

The tracks I used are also sturdier (and heavier) that the usual double pin tension tracks. Since mines are the easiest and likely the most common denial method in the imagined low-tech societies, it was hoped to give more robustness to the vehicle. The speed was limited for the purpose of compensation. I have no feeling how much tnt tracks can survive.

 

-there is a contradiction between the stated height of the turret, roughly 22", and the stated ammunition capacity of 33 rounds of 4.7" ammo. The case head diameter of 4.7" Kraut is roughly 6.7", which cannot be fit 3 deep with armor above and below and in an autoloader within those dimensional limitations.

 

The height of the munuition basket is exactly 23.228" (590mm). This gives 23.228 - (6.7" x 3 + 0,984" (plate thickness roof/bottom)) = 2.14" space. The bustle part of the autoloader has no drum or rotation, just pushing shells out of the boxes, towards the middle.

 

-The autoloader, as described, is unworkable. Doubly so for the replenishment mechanism.
-The gun, as modelled, appears to lack the recoil mechanism. The original Kraut 4.7" gun has a length of approximately 54" from the trunnion to the rear of the breech ring. With this length, and at least 12" for recoil taken into account, we end up with 66" of length from the trunnion to the end of the gun stroke. Even within a fairly large 85" ring, this leaves no room for the 40" , at least, needed for the proposed drum autoloader.
-2-axis elevation pretty much by definition makes stabilization impossible, as at least one, if not both, of the axes are nowhere near the center of gravity of the elevating mass, greatly increasing to unmanageable levels the power required of the elevation drive. Such a system has never before been proposed for a stabilized gun, and for very good reason, namely that it is absurd.

 

XmKutu6.png

 

Recoil space is exactly 19.685". Simulated shell length is 39.37".

There is enough space because the trunion is pushed forward over the turret ring. That would make it quite out of balance, so the cannon with the front axle is inbedded in a frame holding the rear axle and the second stage autoloader with the drum. The weight is distributed all the way back to the rear end of the turret ring with the 1200 lbs autoloader weight. That would further mean a lot of weight on the turret ring so the latter is about 10" broad. If that is feasible goes beyond my, let's say,0 engineering imagination. Might as well be wishful thinking but that is the price of of elevated reloading?

Any more details why the replenishment from the hull would be impossible?

 

the ugly:
-The volume which is supposed to be dedicated to fuel is entirely unclear.

 

wSV8jyY.png

Internals without sponsons and citadel. The black boxes are main and reserve fuel tank. Blue are engine and transmission space. You just had to ask.

The fuel part with the side plate is also exactly the width of the engine box. Hence the mounting parallel with the driver. In that case the shaft needs a transfer towards the middle, into the transmission.

 

-Claimed range is less than desired.

 

Why is that the ugly?

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45 minutes ago, delete013 said:

@N-L-M

First, sorry for the units mess up, it must have been annoying convergin to and fro. Thanks for commenting on my piece too.
I have a few clarifications to provide and a few question to the evaluation.

 

the bad:
-Hull structure insufficiently thick for structural reasons

 

Where is it too thin?

 

-armor does not reach required or claimed protection level (side threat, mine threat, frontal protection of powerpack)

 

My claims about the hull for mission kill are indeed wrong, for the crew compartment are right. The distinction between immobilised tank and crew killed was not specified, afaik. Maybe it is a common knowledge?

Bottom is combined 1.25" in two layers. That is too thin for mine protection?

 

-armor does not provide protection against growth threats.

 

What are growth threats?

 

-engine compartment far too small for the desired powerpack.
-attempting to mount a transverse V12 1500HP engine alongside the driver speaks of a lack of spatial reasoning skills.

 

I had MTU 873 (https://www.yumpu.com/en/document/read/5713483/twelve-cylinder-diesel-engine-mb-873-for-heavy-mtu-shop) main block without turbochargers in mind (turbo would have to be relocated). This leaves about 8 inches of space to the side for some sort of connection with a gearbox of the size of Renk HSWL 295. None of the two are 60ies tech so 1000 HP is more realistic and still fulfills the requirements. The side arrangement is known from T-55 so I assumed it would be possible. Coolers are pushed into sponsons to each side, the 4 big black squares. None of this was exactly decided, but likely indeed too small for existing engines.

 

-Use of single pin, unbushed, tracks gives poor track life, particularly in sandy environments, and is therefore unsuitable to long range self-deploying operations. It is difficult to choose a track link less suitable to the operating environment of the LFS, and along with the overlapped and interleaved suspension speaks of blind cargo culting without understanding the tradeoffs involved.

 

The tracks I used are also sturdier (and heavier) that the usual double pin tension tracks. Since mines are the easiest and likely the most common denial method in the imagined low-tech societies, it was hoped to give more robustness to the vehicle. The speed was limited for the purpose of compensation. I have no feeling how much tnt tracks can survive.

 

-there is a contradiction between the stated height of the turret, roughly 22", and the stated ammunition capacity of 33 rounds of 4.7" ammo. The case head diameter of 4.7" Kraut is roughly 6.7", which cannot be fit 3 deep with armor above and below and in an autoloader within those dimensional limitations.

 

The height of the munuition basket is exactly 23.228" (590mm). This gives 23.228 - (6.7" x 3 + 0,984" (plate thickness roof/bottom)) = 2.14" space. The bustle part of the autoloader has no drum or rotation, just pushing shells out of the boxes, towards the middle.

 

-The autoloader, as described, is unworkable. Doubly so for the replenishment mechanism.
-The gun, as modelled, appears to lack the recoil mechanism. The original Kraut 4.7" gun has a length of approximately 54" from the trunnion to the rear of the breech ring. With this length, and at least 12" for recoil taken into account, we end up with 66" of length from the trunnion to the end of the gun stroke. Even within a fairly large 85" ring, this leaves no room for the 40" , at least, needed for the proposed drum autoloader.
-2-axis elevation pretty much by definition makes stabilization impossible, as at least one, if not both, of the axes are nowhere near the center of gravity of the elevating mass, greatly increasing to unmanageable levels the power required of the elevation drive. Such a system has never before been proposed for a stabilized gun, and for very good reason, namely that it is absurd.

 

XmKutu6.png

 

Recoil space is exactly 19.685". Simulated shell length is 39.37".

There is enough space because the trunion is pushed forward over the turret ring. That would make it quite out of balance, so the cannon with the front axle is inbedded in a frame holding the rear axle and the second stage autoloader with the drum. The weight is distributed all the way back to the rear end of the turret ring with the 1200 lbs autoloader weight. That would further mean a lot of weight on the turret ring so the latter is about 10" broad. If that is feasible goes beyond my, let's say,0 engineering imagination. Might as well be wishful thinking but that is the price of of elevated reloading?

Any more details why the replenishment from the hull would be impossible?

 

the ugly:
-The volume which is supposed to be dedicated to fuel is entirely unclear.

 

wSV8jyY.png

Internals without sponsons and citadel. The black boxes are main and reserve fuel tank. Blue are engine and transmission space. You just had to ask.

The fuel part with the side plate is also exactly the width of the engine box. Hence the mounting parallel with the driver. In that case the shaft needs a transfer towards the middle, into the transmission.

 

-Claimed range is less than desired.

 

Why is that the ugly?

WEW! Ugly cope...

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51 minutes ago, delete013 said:

@N-L-M

First, sorry for the units mess up, it must have been annoying convergin to and fro. Thanks for commenting on my piece too.
I have a few clarifications to provide and a few question to the evaluation.

 

the bad:
-Hull structure insufficiently thick for structural reasons

 

Where is it too thin?

 

-armor does not reach required or claimed protection level (side threat, mine threat, frontal protection of powerpack)

 

My claims about the hull for mission kill are indeed wrong, for the crew compartment are right. The distinction between immobilised tank and crew killed was not specified, afaik. Maybe it is a common knowledge?

Bottom is combined 1.25" in two layers. That is too thin for mine protection?

 

-armor does not provide protection against growth threats.

 

What are growth threats?

 

-engine compartment far too small for the desired powerpack.
-attempting to mount a transverse V12 1500HP engine alongside the driver speaks of a lack of spatial reasoning skills.

 

I had MTU 873 (https://www.yumpu.com/en/document/read/5713483/twelve-cylinder-diesel-engine-mb-873-for-heavy-mtu-shop) main block without turbochargers in mind (turbo would have to be relocated). This leaves about 8 inches of space to the side for some sort of connection with a gearbox of the size of Renk HSWL 295. None of the two are 60ies tech so 1000 HP is more realistic and still fulfills the requirements. The side arrangement is known from T-55 so I assumed it would be possible. Coolers are pushed into sponsons to each side, the 4 big black squares. None of this was exactly decided, but likely indeed too small for existing engines.

 

-Use of single pin, unbushed, tracks gives poor track life, particularly in sandy environments, and is therefore unsuitable to long range self-deploying operations. It is difficult to choose a track link less suitable to the operating environment of the LFS, and along with the overlapped and interleaved suspension speaks of blind cargo culting without understanding the tradeoffs involved.

 

The tracks I used are also sturdier (and heavier) that the usual double pin tension tracks. Since mines are the easiest and likely the most common denial method in the imagined low-tech societies, it was hoped to give more robustness to the vehicle. The speed was limited for the purpose of compensation. I have no feeling how much tnt tracks can survive.

 

-there is a contradiction between the stated height of the turret, roughly 22", and the stated ammunition capacity of 33 rounds of 4.7" ammo. The case head diameter of 4.7" Kraut is roughly 6.7", which cannot be fit 3 deep with armor above and below and in an autoloader within those dimensional limitations.

 

The height of the munuition basket is exactly 23.228" (590mm). This gives 23.228 - (6.7" x 3 + 0,984" (plate thickness roof/bottom)) = 2.14" space. The bustle part of the autoloader has no drum or rotation, just pushing shells out of the boxes, towards the middle.

 

-The autoloader, as described, is unworkable. Doubly so for the replenishment mechanism.
-The gun, as modelled, appears to lack the recoil mechanism. The original Kraut 4.7" gun has a length of approximately 54" from the trunnion to the rear of the breech ring. With this length, and at least 12" for recoil taken into account, we end up with 66" of length from the trunnion to the end of the gun stroke. Even within a fairly large 85" ring, this leaves no room for the 40" , at least, needed for the proposed drum autoloader.
-2-axis elevation pretty much by definition makes stabilization impossible, as at least one, if not both, of the axes are nowhere near the center of gravity of the elevating mass, greatly increasing to unmanageable levels the power required of the elevation drive. Such a system has never before been proposed for a stabilized gun, and for very good reason, namely that it is absurd.

 

XmKutu6.png

 

Recoil space is exactly 19.685". Simulated shell length is 39.37".

There is enough space because the trunion is pushed forward over the turret ring. That would make it quite out of balance, so the cannon with the front axle is inbedded in a frame holding the rear axle and the second stage autoloader with the drum. The weight is distributed all the way back to the rear end of the turret ring with the 1200 lbs autoloader weight. That would further mean a lot of weight on the turret ring so the latter is about 10" broad. If that is feasible goes beyond my, let's say,0 engineering imagination. Might as well be wishful thinking but that is the price of of elevated reloading?

Any more details why the replenishment from the hull would be impossible?

 

the ugly:
-The volume which is supposed to be dedicated to fuel is entirely unclear.

 

wSV8jyY.png

Internals without sponsons and citadel. The black boxes are main and reserve fuel tank. Blue are engine and transmission space. You just had to ask.

The fuel part with the side plate is also exactly the width of the engine box. Hence the mounting parallel with the driver. In that case the shaft needs a transfer towards the middle, into the transmission.

 

-Claimed range is less than desired.

 

Why is that the ugly?


I thought you made it very clear you didn’t want to be here anymore, so why come back? 

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I suppose if you insist on making a fool of yourself in public, we can only cooperate.


 

15 hours ago, delete013 said:

Where is it too thin?

The belly, being 0.6" RHA with an extra 0.4", is not a single plate and will therefore not have nearly the stiffness of a single plate. The rest of the hull and turret structure, likewise, by using 0.8"-1" base plates onto which the thinner armor packs are tacked on, are all very thin for a vehicle of this weight. Especially when one uses a form of suspension which applies high bending loads to the hull sides, and a powerful gun applying high structural loads. The roof too, at 0.4" base with an extra box structure on top, leaves a lot to be desired.
Stiffness scales with the cube of the plate thickness, and the allowable bending moment with the square. In this context, therefore, 2 thin plates, even if rigidly welded into a box structure, are not equivalent to one thick one.
 

 

15 hours ago, delete013 said:

My claims about the hull for mission kill are indeed wrong, for the crew compartment are right. The distinction between immobilised tank and crew killed was not specified, afaik. Maybe it is a common knowledge?

Bottom is combined 1.25" in two layers. That is too thin for mine protection?

No such distinction was offered because no such distinction was requested. The LFS does not look kindly upon this cavalier attitude to vehicle survivability.
Also last time I checked 0.6" plus 0.4" with an air gap between them is less than 1.25" of steel, as well as being significantly less stiff as explained above.

15 hours ago, delete013 said:

What are growth threats?

Cascadian 3.54" HEDP, Cascadian BGM-1 tandem ATGM, and Mormon 2"/4" tandem warhead. at various elevations.
Kudos to @Fareastmenace for correctly guessing 2 out of 3, and being real close on the third.
 

 

15 hours ago, delete013 said:

I had MTU 873 (https://www.yumpu.com/en/document/read/5713483/twelve-cylinder-diesel-engine-mb-873-for-heavy-mtu-shop) main block without turbochargers in mind (turbo would have to be relocated). This leaves about 8 inches of space to the side for some sort of connection with a gearbox of the size of Renk HSWL 295. None of the two are 60ies tech so 1000 HP is more realistic and still fulfills the requirements. The side arrangement is known from T-55 so I assumed it would be possible. Coolers are pushed into sponsons to each side, the 4 big black squares. None of this was exactly decided, but likely indeed too small for existing engines.


The problem is not the concept of transversely mounted engines, but rather your desire to mount one alongside the driver. there is not enough width, this will not fit.
Also, the named engine block will not fit by itself in a 1.5 m^3 engine bay you assigned to it. So again, the point stands, a lack of basic spatial reasoning skills.

If however you mean to put a transverse engine in front of the driver as your model suggests, the question of where all the bits and bobs you've removed from the engine to squeeze it in go, and just how far back a driver has to sit to comfortably fit. The meaning for the length of the engine deck and the position of the turret ring are both clear and negative.
 

 

16 hours ago, delete013 said:

The tracks I used are also sturdier (and heavier) that the usual double pin tension tracks. Since mines are the easiest and likely the most common denial method in the imagined low-tech societies, it was hoped to give more robustness to the vehicle. The speed was limited for the purpose of compensation. I have no feeling how much tnt tracks can survive.

Mines are a distinctly secondary concern to getting places in one piece in the first place, and mines will break single pin tracks too. The much higher wear of a single pin track limits the deployability of the vehicle, as well as its lower energy efficiency lowering both speed and range.
 

 

16 hours ago, delete013 said:

This gives 23.228 - (6.7" x 3 + 0,984" (plate thickness roof/bottom)) = 2.14" space.

a roughly 0.5" top and 0.5" bottom are both very very thin, and even then there's not enough room for the kind of rack mechanism proposed. Shells don't just exist in midair, and the mechanism proposed does not have enough space for the kinds of rails needed. In fact, it hardly has enough space for a static rack. It's also worth noting that 4.7" Kraut, by its nature, has fairly fragile ammunition which needs to be babied to prevent it from falling apart, and so rack solutions such as that used on the IS-7 load assist are not very applicable. Even there, however, the structure to support the rounds was substantial:
autoloader-1.jpg
This of course being the closest system to that which you propose.
One would note that the autoloader must support the ammunition in all the various accelerations and shocks of driving and combat, which with heavy ammunition means a substantial structure is required, one for which you left no room. This structure is also the reason why the proposed mechanized magazine reload is nothing but a joke.
Perhaps by reducing the turret load to 20 rounds such a system could be contemplated, but again the need to protect the combustible case from damage during travel or handling would not be addressed at all.
 

 

17 hours ago, delete013 said:

There is enough space because the trunion is pushed forward over the turret ring. That would make it quite out of balance, so the cannon with the front axle is inbedded in a frame holding the rear axle and the second stage autoloader with the drum. The weight is distributed all the way back to the rear end of the turret ring with the 1200 lbs autoloader weight. That would further mean a lot of weight on the turret ring so the latter is about 10" broad. If that is feasible goes beyond my, let's say,0 engineering imagination. Might as well be wishful thinking but that is the price of of elevated reloading?

2035092_800.png
You appear to have missed quite a bit of the gun's length inboard of the trunnion. Note too that the breech ring extends down quite a bit from the cradle, and the breech block even more when open. All of which speak against the forwards trunnion location even if we ignore the 2-ais solution which is still a farce. The broadly accepted view in the business of armored vehicles is that returning to a loading elevation is perfectly acceptable, and that all-angle loading isn't all that important.
 

 

17 hours ago, delete013 said:

 

Why is that the ugly?

Because it is neither good nor truly bad,  as the minimum requirement is met. And all must be divided up between the good, the bad, and the ugly.
tumblr_mjoeczwgV11rylr5to3_400.gifv
 

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44 minutes ago, N-L-M said:

Cascadian 3.54" HEDP, Cascadian BGM-1 tandem ATGM, and Mormon 2"/4" tandem warhead. at various elevations.

 

We should also note that these are not just nasty surprises the judges are pulling on people, these threats are described in previous competitions (either weapons of the winners, or threats described in other solicitations). Plus, you can simply infer their existence based on the history of the 20th Century.

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19 hours ago, N-L-M said:

I suppose if you insist on making a fool of yourself in public, we can only cooperate.

Whatever makes you happy. My engineering started with this contest, what did you expect? I want my concept torn apart. I've no idea why there is no discussion afterwards, maybe others are afraid the issues of their designs might come out?:rolleyes: I would also expect an exchange of opinions, but some made it so toxic it is likely not going to happen.

 

Anyway, I hope you don't mind discussing a bit more.
 

19 hours ago, N-L-M said:

The belly, being 0.6" RHA with an extra 0.4", is not a single plate and will therefore not have nearly the stiffness of a single plate. The rest of the hull and turret structure, likewise, by using 0.8"-1" base plates onto which the thinner armor packs are tacked on, are all very thin for a vehicle of this weight. Especially when one uses a form of suspension which applies high bending loads to the hull sides, and a powerful gun applying high structural loads. The roof too, at 0.4" base with an extra box structure on top, leaves a lot to be desired.
Stiffness scales with the cube of the plate thickness, and the allowable bending moment with the square. In this context, therefore, 2 thin plates, even if rigidly welded into a box structure, are not equivalent to one thick one.

No such distinction was offered because no such distinction was requested. The LFS does not look kindly upon this cavalier attitude to vehicle survivability.
Also last time I checked 0.6" plus 0.4" with an air gap between them is less than 1.25" of steel, as well as being significantly less stiff as explained above.

I've neither knowledge nor a feeling for materials. My idea for spaced construction was structural steel. Something akin to the vertical I (H) beam in the picture. The info on the stiffness growth is quite interesting.

1-s2.0-S1026309811002471-gr1.jpg

 

1"-1.2" does seem too weak for a side plate in hindsight. I read somewhere that lower side of the Leopard 2 only has about 1" thickness. Maybe wrong info.

I think the weak front hull was indeed an error. Engine should survive impact in the frontal arc of 60 degs. I am satisfied if the rest protects the crew alone, it seems realistic.

 

19 hours ago, N-L-M said:

Cascadian 3.54" HEDP, Cascadian BGM-1 tandem ATGM, and Mormon 2"/4" tandem warhead. at various elevations.
Kudos to @Fareastmenace for correctly guessing 2 out of 3, and being real close on the third.

 

I don't think any of those can hurt my crew with the setup and the specified angles. I wouldn't bet though. The engine is another thing.

19 hours ago, N-L-M said:

The problem is not the concept of transversely mounted engines, but rather your desire to mount one alongside the driver. there is not enough width, this will not fit.
Also, the named engine block will not fit by itself in a 1.5 m^3 engine bay you assigned to it. So again, the point stands, a lack of basic spatial reasoning skills.

If however you mean to put a transverse engine in front of the driver as your model suggests, the question of where all the bits and bobs you've removed from the engine to squeeze it in go, and just how far back a driver has to sit to comfortably fit. The meaning for the length of the engine deck and the position of the turret ring are both clear and negative.

Maybe is said it wrongly, the space for engine alone is more than 3 m^3. Actually it is slightly over 4 and the combined area for power pack is 8 m^3.

 

Main idea was the following

BikJM0g.png

 

This is how it was supposed to look like.

 

bEtyplg.png

 

I initially used EuroPowerPack as an ideal case. It should fit (note the radiator and fans of original engine stretch over the edge of the transmission below). By shifting coolers into sponsons it couldn't be exactly the HSWL 295TM but it is at least a probable combination. Then I compared sizes of older engines. Evidently, German engines are very compact. I also realised that "bits and bobs" wander around designs, I thought, depending on the space available. Such is the case of turbochargers already since ww2. Example in the image below.

v2-ac312472515cf2f7491f13f0c75ad0a0_r.jp

I don't know enough to account for every component that might be missing from usual photos of the engines. I also realise now that in sponsons it might be a problem to propel the cooling fans.

 

You seem to be right about the space next to the driver. It would actually require narrowing the citadel.

 

19 hours ago, N-L-M said:

Mines are a distinctly secondary concern to getting places in one piece in the first place, and mines will break single pin tracks too. The much higher wear of a single pin track limits the deployability of the vehicle, as well as its lower energy efficiency lowering both speed and range.

Fair point.

 

19 hours ago, N-L-M said:

a roughly 0.5" top and 0.5" bottom are both very very thin, and even then there's not enough room for the kind of rack mechanism proposed. Shells don't just exist in midair, and the mechanism proposed does not have enough space for the kinds of rails needed. In fact, it hardly has enough space for a static rack. It's also worth noting that 4.7" Kraut, by its nature, has fairly fragile ammunition which needs to be babied to prevent it from falling apart, and so rack solutions such as that used on the IS-7 load assist are not very applicable. Even there, however, the structure to support the rounds was substantial:
This of course being the closest system to that which you propose.
One would note that the autoloader must support the ammunition in all the various accelerations and shocks of driving and combat, which with heavy ammunition means a substantial structure is required, one for which you left no room.

This structure is also the reason why the proposed mechanized magazine reload is nothing but a joke.
Perhaps by reducing the turret load to 20 rounds such a system could be contemplated, but again the need to protect the combustible case from damage during travel or handling would not be addressed at all.

I admit I never though about the forces and vibrations impacting the ammo. I had two boxes in mind that fill the breech as a assault rifle magazine by being pushed towards the middle from the outer sides by three bars traveling through each of the boxes. That was all quickly made up. I guess more thought would be needed here.

 

19 hours ago, N-L-M said:

2035092_800.png
You appear to have missed quite a bit of the gun's length inboard of the trunnion. Note too that the breech ring extends down quite a bit from the cradle, and the breech block even more when open. All of which speak against the forwards trunnion location even if we ignore the 2-ais solution which is still a farce. The broadly accepted view in the business of armored vehicles is that returning to a loading elevation is perfectly acceptable, and that all-angle loading isn't all that important.

I haven't copied the cannon exactly, only the length. I made the thickened part of the barrel too short and pushed the barrel through the trunnion.

 

I don't know why you would call a two axis mount a farce. Maybe technically impossible, but it seems that modern tanks use a single axis only because it is the simplest solution that still does the job. With an auto-loader and shifting bulge already requiring a frame through the middle of the turret and hydraulics significantly reducing the space once occupied by the gearing, why not add a thing more. A wishful thinking perhaps.

 

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1 hour ago, delete013 said:

I've no idea why there is no discussion afterwards


What the fuck do you think you're doing now?

 

1 hour ago, delete013 said:

maybe others are afraid


LMAO projection, much?

 

1 hour ago, delete013 said:

Anyway, I hope you don't mind discussing a bit more.


With your shitty attitude? We mind mightily. You've been a banned man walking for months, now.

 

1 hour ago, delete013 said:

I've neither knowledge nor a feeling for materials.


It's funny that now you're professing your ignorance on virtually every subject from materials to engineering to what hole the square block goes into, but months ago you waltzed around chewing people out for how "ignorant" you thought they were because they didn't think Tiger was the best thing since sliced bread.
 

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17 minutes ago, Sturgeon said:


What the fuck do you think you're doing now?

I'm trying to be constructive.

 

17 minutes ago, Sturgeon said:

With your shitty attitude? We mind mightily. You've been a banned man walking for months, now.

So what should I do to, to make my attitude acceptable?

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8 hours ago, delete013 said:

I'm trying to be constructive.

 

So what should I do to, to make my attitude acceptable?


What you’re doing now, accepting that you don’t know everything, is a more acceptable attitude, but it’s a couple months late. 

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    • 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
      Addendum 1 - more armor details
      Good luck, and may Hubbard guide your way to enlightenment!
    • By Sturgeon
      The LORD was with the men of Deseret. They took possession of the hill country, but they were unable to drive the people from the plains, because they had chariots of steel.
      —The Book of Latter Day Saints, Ch 8, vs. 3:10, circa 25th Century CE
       
      BULLETIN: ALL INDUSTRIAL-MECHANICAL CONCERNS
       
      SOLICITATION FOR ALL-TERRAIN BATTLE TANK
       
      The Provisional Government of the Lone Free State of Texas and The Great Plains issues the following solicitation for a new All-Terrain Battle Tank. The vehicle will be the main line ground combat asset of the Lone Free State Rangers, and the Texas Free State Patrol, and will replace the ageing G-12 Scout Truck, and fill the role of the cancelled G-42 Scout Truck. The All-Terrain Battle Tank (ATBT) will be required to counter the new Californian and Cascadian vehicles and weapons which our intelligence indicates are being used in the western coast of the continent. Please see the attached sheet for a full list of solicitation requirements.
       

       
      Submissions will be accepted in USC only.
       
       
      Supplementary Out of Canon Information:
       
       
      I.     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 judge.
      Structural materials:
                                                                    i.     RHA/CHA
      Basic steel armor, 360 BHN. The reference for all weapon penetration figures, good impact properties, fully weldable. Available in thicknesses up to 4 inches (RHA) 8 inches (CHA). 
      Density- 0.28 lb/in^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 4 inches.
      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- 0.1 lb/in^3 (approx. 1/3 of steel).
      For structural integrity, the following guidelines are recommended:
      For heavy vehicles (30-40 tons), not less than 1 in RHA/1.75 in Aluminum base structure
      For medium-light vehicles (<25 tons), not less than 0.5 in RHA/1 in 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 1.5x as effective as RHA against KE and HEAT on a per-weight basis. Not weldable, middling shock properties. Available in thicknesses up to 1 inch.
      Density- 0.28 lb/in^3
                                                                  iv.     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-0.03 lb/in^3.
                                                                v.     Assorted stowage/systems
      Mass efficiency vs RHA- 1 vs CE, 0.8 vs KE.
                                                               vi.     Spaced armor
      Requires a face of at least 1 inch LOS vs CE, and at least 0.75 caliber LOS vs fullbore AP KE.
      Reduces penetration by a factor of 1.1 vs CE or 1.05 vs KE for every 4 inchair gap.
      Spaced armor rules only apply after any standoff surplus to the requirements of a reactive cassette.
      Reactive armor materials:
                                                                  vii.     ERA
      A sandwich of 0.125in/0.125in/0.125in steel-explodium-steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 2 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).
                                                                  viii.     NERA
      A sandwich of 0.25in steel/0.25in rubber/0.25in 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.     Bofors 57mm (reference weapon) - 85,000 PSI PMax/70,000 PSI Peak Operating Pressure, high quality steel cases, recoil mechanisms and so on are at an equivalent level to that of the USA in the year 1960.
                                                                   ii.     No APFSDS currently in use, experimental weapons only - Spindle sabots or bourelleted sabots, see for example the Soviet BM-20 100mm APFSDS.
                                                                  iii.     Tungsten is available for tooling but not formable into long rod penetrators. It is available for penetrators up to 6 calibers L:D.
                                                                  iv.     Texan shaped charge technology - 4 CD penetration for high-pressure resistant HEAT, 5 CD for low pressure/ precision formed HEAT.
                                                                   v.     The subsidy-approved GPMG for the Lone Free State of Texas has the same form factor as the M240, but with switchable feed direction.. The standard HMG has the same form factor as the Kord, but with switchable feed direction.
      c.       Mobility
                                                                    i.     Engines tech level:
      1.      MB 838 (830 HP)
      2.      AVDS-1790-5A (908 HP)
      3.      Kharkov 5TD (600 HP)
      4.    Detroit Diesel 8V92 (400 HP)
      5.    Detroit Diesel 6V53 (200 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- Gen 2 maximum
                                                                  vi.     Texas cannot mass produce microprocessors or integrated circuits
                                                                 vii.    Really early transistors only (e.g., transistor radio)
                                                                viii.    While it is known states exist with more advanced computer technology, the import of such systems are barred by the east coast states who do not approve of their use by militaristic entities.
       
      Armor calculation appendix.
       
      SHEET 1 Armor defeat calculator 4in-54 1200 yd
       
      SHEET 2 Armor defeat calculator 4in-54 2000 yd
       
      SHEET 3 Armor defeat calculator 6in HEAT
       
      Range calculator
       
    • By Toxn
      This is the competition entry thread.
       
      Please submit your complete entries here (all entries will be judged complete when judging begins in the first week of November) and keep the other competition thread for discussion and chatter.
       
      Once judging is complete I will make a post here to discuss the entries and announce a winner.
       
      Best of luck!
       
      Update: final submissions should be in hand by the 22nd of November 2020.
    • By SH_MM
      Found a few higher resolution photographs from the recent North Korean military parade. We didn't have a topic for BEST KOREAN armored fighting vehicles, so here it is.
       
      New main battle tank, Abrams-Armata clone based on Ch'ŏnma turret design (welded, box-shaped turret) and Sŏn'gun hull design (i.e. centerline driver's position). The bolts of the armor on the hull front is finally visible given the increased resolution. It might not be ERA given the lack of lines inbetween. Maybe is a NERA module akin to the MEXAS hull add-on armor for the Leopard 2A5?
       
      Other details include an APS with four radar panels (the side-mounted radar panels look a lot different - and a lot more real - than the ones mounted at the turret corners) and twelve countermeasures in four banks (two banks à three launchers each at the turret front, two banks à three launchers on the left and right side of the turret). Thermal imagers for gunner and commander, meteorological mast, two laser warning receivers, 115 mm smoothbore gun without thermal sleeve but with muzze reference system, 30 mm grenade launcher on the turret, six smoke grenade dischargers (three at each turret rear corner)
       


       
      IMO the layout of the roof-mounted ERA is really odd. Either the armor array covering the left turret cheek is significantly thinner than the armor on the right turret cheek or the roof-mounted ERA overlaps with the armor.
       


      The first ERA/armor element of the skirt is connected by hinges and can probably swivel to allow better access to the track. There is a cut-out in the slat armor for the engine exhaust. Also note the actual turret ring - very small diameter compared to the outer dimensions of the turret.
       
      Stryker MGS copy with D-30 field gun clone and mid engine:

      Note there are four crew hatches. Driver (on the left front of the vehicle), commander (on the right front of the vehicle, seat is placed a bit further back), gunner (left side of the gun's overhead mount, next to the gunner's sight) and unknown crew member (right side of gun's overhead mount with 30 mm automatic grenade launcher mounted at the hatch). The vehicle also has a thermal imager and laser rangefinder (gunner's sight is identical to the new tank), but no independent optic for the commander. It also has the same meteorological mast and laser warner receivers as the new MBT.
       
      What is the purpose of the fourth crew member? He cannot realistically load the gun...
       
      The vehicle has a small trim vane for swimming, the side armor is made of very thin spaced steel that is bend on multiple spots, so it clearly is not ceramic armor as fitted to the actual Stryker.

       
      The tank destroyer variant of the same Stryker MGS copy fitted with a Bulsae-3 ATGM launcher.
       

      Note that there is again a third hatch with 30 mm automatic grenade launcher behind the commander's position. Laser warning receivers and trime vane are again stand-out features. The sighting complex for the Bulsae-3 ATGMs is different with a large circular optic (fitted with cover) probably being a thermal imager and two smaller lenses visible on the very right (as seen from the vehicle's point of view) probably containing a day sight and parts of the guidance system.
       

      Non line-of-sight ATGM carrier based on the 6x6 local variant of the BTR, again fitted with laser warning receivers and a trim vane. There are only two hatches and two windows, but there is a three men crew inside.
       
       
      There are a lot more photos here, but most of them are infantry of missile system (MLRS' and ICBMs).
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