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Just now, Xoon said:

How does filling wheels with water act as a shock dampener? 

If you run over a mine, the wheel is the first thing that gets blown up by it. Filling the tire with water means that part of the explosion's energy is spent in moving all that water mass out of the way before it gets to the hull. So, uh, sacrificial dampening I guess.

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2 minutes ago, Toxn said:

If you run over a mine, the wheel is the first thing that gets blown up by it. Filling the tire with water means that part of the explosion's energy is spent in moving all that water mass out of the way before it gets to the hull. So, uh, sacrificial dampening I guess.

More mass to absorb the energy from the blast basically. 
 

To be honest, it sounds about as effective as track/concrete armor during WWII, or improvised slat armor in the Syrian Civil War.

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Just now, Xoon said:

More mass to absorb the energy from the blast basically. 
 

To be honest, it sounds about as effective as track/concrete armor during WWII, or improvised slat armor in the Syrian Civil War.

It should be a bit better than improvised solid armour, because it won't transmit the shock wave very well and uses up a significant amount of energy in dispersion.

 

If you mean instead that its mainly a psychological comfort rather than something practical, I think you should remember that explosive injuries are less all-or-nothing than kinetic ones. Anything you do to disperse or redirect the blast and associated shockwave results in less injuries. Sling seats, for instance, have been shown to have a measurable effect in reducing blast injuries despite doing very little to directly protect the occupants of the vehicle. Instead they function by providing a few more centimetres of standoff and lowering transmission of the shockwave through the body.

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2 hours ago, Toxn said:

It should be a bit better than improvised solid armour, because it won't transmit the shock wave very well and uses up a significant amount of energy in dispersion.

 

If you mean instead that its mainly a psychological comfort rather than something practical, I think you should remember that explosive injuries are less all-or-nothing than kinetic ones. Anything you do to disperse or redirect the blast and associated shockwave results in less injuries. Sling seats, for instance, have been shown to have a measurable effect in reducing blast injuries despite doing very little to directly protect the occupants of the vehicle. Instead they function by providing a few more centimetres of standoff and lowering transmission of the shockwave through the body.

I was thinking about the fact that filling the wheels with water would reduce the effectiveness of the wheels, and the sandbags would weigh down the vehicle. 
Also about the psychological part, if the troops feel safe, then it is good enough makeshift measure.

 

Reminds me of how the Norwegian Armed Forces used to sometimes fill the empty cavity in the doors of their cars with sand for extra bullet protection in the middle east.

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I got to thinking on the merits of the actual double-V (and not the compound V that I was thinking was double-V whoops) - and since the idea seems to be to minimize the amount of area that has to be reinforced (only the trough, and even it is supposed to be slightly concave and open at the ends to vent blast forwards/back) would something like a triple-V not be better? Put third V where the trough is to make two smaller troughs, these will be more concentrated and have to be more heavily reinforced but would not heavily reinforcing those two very small troughs be similar in weight to reinforcing the single large trough while taking up less interior space?

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To come back on electrical propulsion and whether it would be better to have one electrical engine per track or one central engine and a transmission.

I was at a conference-debate about electrical mobility this evening and one of the contributor was a regular participant of the Monte-Calro eRallye (for 100% electric or hydrogen cars).

 

According to him, last year one of the electrical car which entered the competition had motor-wheels which gave it quite fantastic performances, compared to more common vehicles with a single central engine.

However the RPM of an electrical engine being vastly greater than the one of a wheel (or a track) a reductor was still needed and it was under heavy stress which led to a high wear rate.

He also claimed that it increased the noise generation quite a lot.

 

Increased noise would be irrelevant for a tank since I guess that the tracks would make way more noise on themselves anyway.

A high wear rate could be more problematic.

 

Since I'm not really well versed in mechanics I don't know if his claims are valid or not.

 

Edit: I think he was talking about this particular system (maybe others layout bypass the problem)

 

 

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I would love for electric motors to result in a return to convertible tanks, like the christie tanks

szt3-1.jpg

 

The situation for wheeled vehicles isn't quite comparable, as you're force limited by the tyres. 4 wheel drive helps with this for cars, but with the inefficiency of the transfer cases and such sapping power. For a tank the drive sprocket is essentially geared to the track, so driving the road wheels wouldn't get you any better transfer of force to the ground (as the tracks will slip long before the drive sprocket shears teeth or skips a tooth for properly tensioned track, and all of the weight of the vehicle is already giving you friction to apply motive force).

 

One potential benefit is retaining mobility if you lose a drive sprocket, but I'd imagine it would be rare for something big enough to a) hit the drive sprocket and b) not wreck the engine bay. Mines normally damage the front road wheels, and those can be bypassed with short tracking.

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15 hours ago, Alzoc said:

To come back on electrical propulsion and whether it would be better to have one electrical engine per track or one central engine and a transmission.

I was at a conference-debate about electrical mobility this evening and one of the contributor was a regular participant of the Monte-Calro eRallye (for 100% electric or hydrogen cars).

 

According to him, last year one of the electrical car which entered the competition had motor-wheels which gave it quite fantastic performances, compared to more common vehicles with a single central engine.

However the RPM of an electrical engine being vastly greater than the one of a wheel (or a track) a reductor was still needed and it was under heavy stress which led to a high wear rate.

He also claimed that it increased the noise generation quite a lot.

 

Increased noise would be irrelevant for a tank since I guess that the tracks would make way more noise on themselves anyway.

A high wear rate could be more problematic.

 

Since I'm not really well versed in mechanics I don't know if his claims are valid or not.

 

Edit: I think he was talking about this particular system (maybe others layout bypass the problem)

 

 

There is really no point in having a transmission for a series hybrid electric tank. The PWM motor controller works as the gearbox, the gearbox would only cause a drop in efficiency and take up considerable space. 
All motors should be geared, as it is more efficient than adding poles to reduce the RPM and increase the torque. This is accomplished by the final drive.

 

For wheeled death traps, it can be a pretty huge thing. Being able to remove the drive shafts under the crew compartment would mean a much lower vehicle. Being able  to move the motors outside the chassis and inside the wheels would greatly increase space. Also, the vehicle can effectively torque steer. 

 

However, it comes at a cost. You can only fit a so and so big motor and reduction gear inside the wheel, limiting power. The motor and reduction gear is also more exposed to damage and the outside environment, leading to more wear and tear. Cooling can also be a issue. 

 

I would not expect more than 600hp combined. So no super heavy wheeled death traps.

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  • 4 months later...

Hello, I'm new here. Just saw this and it looks interesting so I decided to dig it up.

 

I wonder why I didn't see anyone bring up the Object.640-style layout? I think it'd also be compatible with crew capsule. For example, taking autoloader out from under Armata's turret, add the bustle-type autoloader, and put Commander and Gunner inside the free space inside a turret basket, with crew capsule around it, and make all of them sit below the hull line. It would also decrease the chance of the one-penetration crew massacre.

 

image001.gif

 

As far as I can remember, one of the major disadvantage of it is lacks of "Mk1 eyeball-style" surveillance capability, the commander cannot see much peeking through the periscope as the FOV is very limited, and then-use-only-panoramic-sight solution isn't the best option for maximum situational awareness...but that might be solved by redesigning it so that other parts of the tank doesn't block its FOV as much as it was (although it may increase profile of the tank), or one can supplement it with the fiberscopes that would not require as much area as adding more rigid and bigger-than-normal (since crew sits inside the hull, or nearly, in case of the real Obj.640) periscopes

DSCN1930.JPG

 

It could also be supplemented by surveillance system similar to Israeli IronVision

maxresdefault.jpg

Something like this, I imagine.

pM7Uyhb.png

There'd be a lot of space to put the Hard-kill APS (presumably launcher-based, blast-type one that has long range to counter heavy, especially top-attack ATGMs) and associated electronics (such as the APS' surveillance/tracking radars, LWR, and aircraft-like MAWS) and still having lower turret profile than the full turret tanks (although may have bigger hull), and also room on driver's side to put the air conditioning unit (that would also act as cooling system for the more and more sophisticated electronics), electronic systems and batteries (which would be required more and more due to the same reason) AND another Hard-kill APS (presumably box-based, flyer-type one for the anti-KE job, this one would function like Ukrainian Nozh ERA but instead of shaped charges being launched to cut the penetrator apart, it use electromagnetically-propelled metal flyers, I think I've read it somewhere that it's effective against KE in tests but weren't given development priority due to the major asymmetric warfare threats tend to be shaped charges, especially from shoulder-fired weapon at relatively short range)

 

Also, I think the basket/capsule could be designed to be "disconnected" from the turret (with another pair of hatches), hence it may have higher chance for the crew to survive the top-attack ATGMs (as they need to go through a lot of things inside the turret, including the empty space - thus creating more distance, which is important to be optimum for the shaped charges to be effective, and the crew has another layer of "basket's roof" protection)

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Welcome to SH! 

 

Personally I love the Obj. 640, it's quite the innovative design (at least, if it works as advertised, which is always and adventure when talking about prototypes and test beds). But some of the things you mentioned I don't think would help. 

 

9 hours ago, ro1994 said:

put Commander and Gunner inside the free space inside a turret basket, with crew capsule around it, and make all of them sit below the hull line. It would also decrease the chance of the one-penetration crew massacre.

 

Yes, sure, this is indeed a solution to a problem. But how much of a problem is it? Often times, when a vehicle is penetrated, comparatively few crew become casualties, as described here. (just click the text and it will take you to another site, where I got my info). 

 

Quote

Attrition, Fig. 50

 

The biggest threat to a "complete crew kill" would be a catastrophic ammo explosion, but since the ammo is separated, there's not a lot of threat from that. In general, placing crew below the turret line would be a better solution that separating out the crew, rather than with some within a crew capsule and some outside (this might cause resentment and animosity from the crew placed outside the capsule, as the capsule obviously has better protection). 

 

 

 

9 hours ago, ro1994 said:

As far as I can remember, one of the major disadvantage of it is lacks of "Mk1 eyeball-style" surveillance capability, the commander cannot see much peeking through the periscope as the FOV is very limited, and then-use-only-panoramic-sight solution isn't the best option for maximum situational awareness...but that might be solved by redesigning it so that other parts of the tank doesn't block its FOV as much as it was (although it may increase profile of the tank), or one can supplement it with the fiberscopes that would not require as much area as adding more rigid and bigger-than-normal (since crew sits inside the hull, or nearly, in case of the real Obj.640) periscopes 

DSCN1930.JPG

 

It could also be supplemented by surveillance system similar to Israeli IronVision

maxresdefault.jpg

 

 

this is exactly the problem products like "Iron Vision" are trying to solve. No matter how many periscopes you place around the tank, you will never have as much situational awareness as if you just stick your head out a hatch, without possibly compromising the armor of said tank. With Iron Vision, and similar products, you don't even need your crew in the vehicle (so long as you can keep a secure connection), but it's probably better to keep them in (some of) the tanks. And as you said, this would negate the problems with having all your crew in the hull (though, purportedly, the Armata doesn't have bad situational awareness). 

 

 

 

9 hours ago, ro1994 said:

Also, I think the basket/capsule could be designed to be "disconnected" from the turret (with another pair of hatches), hence it may have higher chance for the crew to survive the top-attack ATGMs (as they need to go through a lot of things inside the turret, including the empty space - thus creating more distance, which is important to be optimum for the shaped charges to be effective, and the crew has another layer of "basket's roof" protection)

 

Hmmm, so they have to open a hatch to get into the turret space, then another hatch to get outside? That sounds like a little to much work. 

 

 

 

If I were to make a design, I would make the tank similar to the Merkava (front engine, rear crew space). With the introduction of the Mark 4, the front hull armor is quite good yet doesn't impede maintenance of the engine, while the rear compartment places the crew as far away from enemy gunfire as possible (whilst still remaining within the tank). The turret would be unmanned, with a bustle loader, launcher based APS (Iron Fist, more specifically), autocannon resistant (lets say resists 25mm M791 from the M242 at 250m), and placed upon the hull roof, separated from the crew. All 4 crew (commander, gunner, driver, robotic wingman operator*) would be in the hull, just below the turret (with the turret mass generally covering the crew from above), and equip them with an under armor surveillance system (i.e. Iron Vision). 

 

* The "robotic wingman operator" would be a crew member who manages (and possibly controls, if armed) the various unmanned ground, aerial, and (if applicable) floating/submerged vehicles that assist the tank in battle. 

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   Object 490 had turret bustle mounted autoloader, with additional rounds mounted between engine and crew compartment. Both ammoracks were protected/separated from the crew and had blow out panels. Object 640 is not a new designs, it is just attempt to mix T-80 with some of ideas that were used on Object 490.

 

img003.jpg

 

   This layout have problems. Having big ass turret bustle is not going to increase overall survivability of tank under fire. It increases side projection and frontal projection in 60 degr arc of a tank in worst place - area higher above the ground, where statistically more hits are happening. Placing ammo in the hull is preferable. 

   Also increasig size of turret isn't good idea for vehicles fighting in urban conditions. They already have long gun barrels to worry about, but gunner can at least see what is happening near muzzle end of guns (usually), unlike turret bustle. 

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5 hours ago, LoooSeR said:

   Object 490 had turret bustle mounted autoloader, with additional rounds mounted between engine and crew compartment. Both ammoracks were protected/separated from the crew and had blow out panels. Object 640 is not a new designs, it is just attempt to mix T-80 with some of ideas that were used on Object 490.

 

img003.jpg

 

   This layout have problems. Having big ass turret bustle is not going to increase overall survivability of tank under fire. It increases side projection and frontal projection in 60 degr arc of a tank in worst place - area higher above the ground, where statistically more hits are happening. Placing ammo in the hull is preferable. 

   Also increasig size of turret isn't good idea for vehicles fighting in urban conditions. They already have long gun barrels to worry about, but gunner can at least see what is happening near muzzle end of guns (usually), unlike turret bustle. 

 

 

The first version had "big ass turret bustle " for 1400 mm long round and charge, but then they -

On subsequent version with a double-flow automatic loader with separate loading rounds was proposed.  The projectile and charge were placed in turret bustle and hull sequentially (… round-charge-round …). http://btvt.info/7english/490_eng.htm

This made loading a bit longer, but the turret bustle length was 2 times shorter.

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1 hour ago, Andrei_bt said:

 

 

The first version had "big ass turret bustle " for 1400 mm long round and charge, but then they -

On subsequent version with a double-flow automatic loader with separate loading rounds was proposed.  The projectile and charge were placed in turret bustle and hull sequentially (… round-charge-round …). http://btvt.info/7english/490_eng.htm

This made loading a bit longer, but the turret bustle length was 2 times shorter.

I was talking about Object 640/Black Eagle turret. It does have a big turret bustle.

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  • 1 month later...
On 12/8/2017 at 10:38 PM, Serge said:

It depends on what you want to achieve but the rule is the following : when heavy load must be carried, use track drive train. 

It more compact by a 1/3.

 

Considering just the weight, if you want to put Leclerc MBT on wheels, you will have 6 more tons. Abrams or Leopard will be higher by 2t. I don’t want to think about Challenger 2 or Merkava Mk4.

And I don’t think about cross country capability. 

 

Why? 

 

 

Independent axle with subframe, suspension and everything but the wheels and tires and load capacity with 15 tons weighs 1 ton.

Tires and wheels capable of 7.5 ton weighs 200-300 kg.

Transmission for trucks with max 3000 nm input weighs about 500kg compared to renk transmission for trucked vechiles which for 60 ton machine weighs more then 2 tons.

And wheeled vechiles multiply torque by axles and wheelhubs.

 

So for 4 axles and 8 tires with weight of 6 ton gives you capacity to carry 55-60 tons.

 

Ok there are driveshafts that are not used in track vechile, but those weigh not too much (i dont know how much but each maybe max 100kg). for 4axle you need 3 of them. 

 

Also because of torque multiplication and low resistance from wheels you gonna need less powerful engine then on tracked ?! (Maybe) 

 

 

https://www.tatratrucks.com/trucks/customer-segment-catalog/defence/more-trucks/8x8-high-mobility-heavy-duty-chassis/ this chassis with everything weighs 13 tons, but on it you got frame (tatra frame with it tube is robust but weighs too much) which is unnecessary on heavy vechiles.

 

 

 

Any approximate weight of  suspension of tracked vechiles of 60 tons?

 

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  • 4 weeks later...

Yes, Challenger and Abrams (just to cite two) use some of their multiple fuel tanks (side sponsons and the entire hull area around the driver, respectively) as makeshift protection against HEAT-based weaponry. The fluid simply slows down the HEAT copper jet. I don't have the number in my head right now, but IIRC 8cm of fuel in a HEAT jet's path is the rough equivalent of 1cm of steel (and you have two advantages here: that [filled] fuel tank is obviously going to be lighter than a solid slab of steel and you don't waste internal volume, instead using it to transport more fuel and therefore extend your operational range).

 

You need to ask Bronezhilet for dead-tree and online literature, though.

 

Spoiler

https://www.scribd.com/document/33225104/Tank-Combat-120mm-Challenger-Part-1-Automotive-System

 

^--- Pages 105 & 106 (in viewer) describe the location and shapes of the Challenger fuel tanks, but doesn't address the anti-HEAT properties of these modules.

 

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5 hours ago, XDrake said:

Is it true that some tank designs incorporate fuel tanks as armor? How do fuel tanks work as armor and is there any literature on that?

 

According to Richard M. Ogorkiewicz's absolutely indispensible Everything You Ever Wanted to Know About Tanks* but Were Afraid to Askdiesel fuel has a mass efficiency of about 3 against shaped charges.  That is to say, it is 3 times as effective as steel RHA, pound for pound.  But, given the disparity in densities, this means that you need about 3 inches of diesel to match the protection of 1 inch of conventional steel armor.  He does say that cellular fuel storage systems can "in practice it can be more than that."  I think @SH_MM had some information on these sorts of fuel cell armor arrays.

 

So, a good old-fashioned Malyutka will penetrate about 450mm of RHA.  To stop the shaped charge jet just with diesel fuel, you would need a fuel tank that's nearly a meter and a half deep.  That's clearly impractical.  But supposing instead you had a hull design with 220mm RHA LOS (e.g. a 93mm glacis plate set back at 65 degrees, just like the M60 has) followed by 700mm deep fuel tanks, wrapped around the driver.  That could work.  If it's the 1970s, and you've just noticed that MBTs are dying in droves to guided missiles, and that fancy composite armor the boffins keep talking about isn't quite ready for mass-production yet, this would be a practical approach to making main battle tanks don't die quite so easily.

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@Renegade334 @Collimatrix Thanks for your responses I thought I read something about fuel tanks being used as armor. Interesting stuff. I think its not only internal fueltanks that serve as chemical penetrator protection in some cases. The Stridsvagn 103 also has some jerry cans placed alongside the hull sides. Id imagine that placement has the same goal in mind. 

 

Spoiler

Stridsvagn_103_Revinge_2012-3.jpg

 

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      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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