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    T-90 Main Battle Tank #2

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    Cyrus the great

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    Post  Cyrus the great on Sat Aug 10, 2019 6:20 am

    I've been reading up more on liquid and gel propellants and I wonder if it's possible to incorporate a gel propellant into the hull of the current T-90M Proryv-3; gel propellants have all the advantages of solid propellants -> storage and portability and the advantages of liquid propellants -> safety increase, reduced volume requirements, reduced sensitivity, reduced flammibility, increased velocity and improvements in logistics in the ammunition re-supply system.

    U.S. studies on the feasibility of incorporating such a propellant into the M1 Abrams conclude that it would increase the ready rounds from 17 to 48 and increase the amount of stowed rounds from 40 to 56.

    If there was room in the hull of the T-90M Proryv-3 to store binary liquid or gel propellant on opposite ends of the tank, you could remove propellant explosions altogether and could conceivably double the rounds in the carousel autoloader from 22 to 44. By separating and placing the fuel and the oxidizer on opposite ends of the T-90M, Russia would have the safest tank crews in the two safest tanks. Liquid propellants are (by weight) less than 1% combustibles whereas solid propellants are 40%.

    I also like the idea of including a small bustle autoloader (with 16 sabot rounds) in the turret -- bringing the ready to fire rounds to 60. Is any of this possible for the T-90? And would it be worth the investment?
    GarryB
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    Post  GarryB on Sat Aug 10, 2019 11:47 am

    They developed a bustle autoloader for an upgrade of the T-72/90 vehicle family based on that of the Black Eagle design.

    On the black eagle it was supposed to replace the underfloor autoloader, but they ended up deciding that placing ammo in such an exposed location would make it too vulnerable to enemy fire.

    Of course removing all propellent and HE content and just having sabot rounds there with the propellent stored in tanks elsewhere inside the tank... perhaps with some sort of microwave priming of the propellent so it might not even burn if hit where it is stored would make all the difference.

    The original turret bustle autoloader had 31 rounds in it, but that included propellent stubs, so 62 sabot rounds in the turret bustle, and 44 more rounds in the underfloor autoloader that could be HEFRAG and HEAT and of course missile rounds... in two layers, with the propellent stored separately inside the tank would be rather interesting...

    Making it fully fluid and only thicken to a gel inside the chamber would make pumping it around the tank much easier and quicker, and with a binary fluid that can be pumped into the chamber and then primed perhaps with a microwave beam to activate it, it should be rather useful and safe and you could probably boost MV by 20% or more with the more powerful propellent.
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    Cyrus the great

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    Post  Cyrus the great on Sat Aug 10, 2019 1:30 pm

    GarryB wrote:They developed a bustle autoloader for an upgrade of the T-72/90 vehicle family based on that of the Black Eagle design.

    On the black eagle it was supposed to replace the underfloor autoloader, but they ended up deciding that placing ammo in such an exposed location would make it too vulnerable to enemy fire.

    Of course removing all propellent and HE content and just having sabot rounds there with the propellent stored in tanks elsewhere inside the tank... perhaps with some sort of microwave priming of the propellent so it might not even burn if hit where it is stored would make all the difference.

    The original turret bustle autoloader had 31 rounds in it, but that included propellent stubs, so 62 sabot rounds in the turret bustle, and 44 more rounds in the underfloor autoloader that could be HEFRAG and HEAT and of course missile rounds... in two layers, with the propellent stored separately inside the tank would be rather interesting...

    Making it fully fluid and only thicken to a gel inside the chamber would make pumping it around the tank much easier and quicker, and with a binary fluid that can be pumped into the chamber and then primed perhaps with a microwave beam to activate it, it should be rather useful and safe and you could probably boost MV by 20% or more with the more powerful propellent.

    Garry

    Thanks for this detailed and useful response, mate. I just looked up information on microwave shell priming systems, and I was pleasantly surprised to find that this is already in place with the Koalitsiya-SV - so this certainly can be incorporated into the T-90M. The papers I've read point out that "most BLLPG which have overpressured and led to a failure have been blamed on errors in ignition."

    This issue can be removed now that Russia has a working microwave shell priming system. I like the turret size of the 22 capacity Leclerc tank, and I don't think it would affect the center of gravity of a T-90M. The Black Eagle tank had a turret that seemed a little too large, even if it could hold 62 sabot rounds and I'm not sure there would be enough propellant for a combined 106 rounds.

    The other issue with liquid propellant is contamination, but I'm certain that this can be rectified. I'm just not sure where liquid propellants could be placed into the T-90M - as there is little space inside MBTs; I suppose one liquid propellant tank could be put where the 8 hull stored rounds are right now.

    I just think that the T-90 has more potential than even its latest variant, and this is why I think they should include an APS, the 2a82 gun, the T-14 Mission computer, data links, BMS, third generation thermals and a liquid or gel propellant.
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    Post  GarryB on Sat Aug 10, 2019 2:05 pm

    A critical point regarding safety is that if you have a HE round inside a tank loaded in an auto loader system it needs to have a fuse system.

    Something that will make the main HE charge go boom.

    The problem is that generally to make HE go boom you need low explosive.

    You need a boom to get a boom from a high order explosive.

    The problem for a tank that has been hit is that all its HE rounds... including HEAT rounds as well, is that if you set fire to a HE round the HE will actually just burn and be less of a problem than propellent actually.

    It is the fuse that contains a low explosive like gunpowder that readily explodes that will set off the main charge that is the problem because if the fuse catches fire or is heated beyond a certain rather low temperature then when it explodes it will set off the main HE charge explosion, which in turn will set off other HE and HEAT rounds nearby and of course any propellent in one big explosion.

    Without the fuses a stack of HE shells will just burn for quite some time... the temperature would need to get to rather high levels before it actually explodes.

    Having a microwave system of setting off the propellent and an electric fuse for setting off the explosives on impact greatly reduce the risks in handling the rounds and in case the vehicle is hit.

    Of course even diesel will explode when it gets heated to a high temperature, but removing the propellant and keeping it separate from the ammo should make it much safer.

    Equally with Sabot rounds in the turret bustle... you could offset their positions so their sabots overlap and greatly reduce the space they take up as they wont need to be surrounded by propellent... in fact it would be better if they didn't have propellent around them to make them lighter and more compact in storage.

    Generally modern Sabot rounds have bore width petals at the front and the back to align the projectile with the barrel but in between they can be as narrow as the round itself... about 60-80mm for a projectile about 40-50mm across, so you could stack them so that they interlock and you should be able to get quite a few in there.

    BTW from memory I think the Burlak turret bustle autoloader had 31 positions for rounds... projectiles and propellent stubs... one in front of the other in each tube so the 31 tubes would have 31 projectiles and 31 propellent stubs. This new design with liquid propellent could do away with the propellent stubs and just have perhaps 32 APFSDS rounds of about half the bustle length but the same width.

    Regarding the location for the propellent if you separate it into two separate liquids that are relatively inert on their own you could create layers inside the armour with cells of the different propellent types... say 8 separate fuel compartments in the front of the hull... upper and lower... so that any penetration wont take out all of one propellent component... and it would act like spaced armour rendering rounds like HESH useless.

    Then of course having the other component in the rear of the hull in the position between the turret and the engine where the upgraded T-90 carries an extra 6 rounds of ammo... a tank there with tubes to pump it into the gun chamber and perhaps secondary tanks in each side of the turret bustle for redundancy... turn the turret forward and pump 20 litres or so into the turret tanks... you could even put the tanks under the commander and gunners seats moving around with the turret so with fixed pipes from the seats to the rear of the gun... with further pipes leading from the rear bustle to the gun where the two chemicals are mixed and prepared for firing...

    The liquids would not necessarily be pleasant, but separately they might not even burn let alone explode.

    You might mix 300mls of one liquid with 1,000mls of the other for a high energy APFSDS round shot, whereas HE and HEAT rounds might only need 100mls of one liquid and 600mls of the other... depending on the condition and the situation the computer could probably alter the mix to improve performance in different situations...

    When reloading the tank you could have an external cap to load into the hull and turret tanks rather quickly... make the hose connectors specific to the tank so mistakes are not made... but even hosing the wrong material into the wrong tank it would still need to be microwaved to work properly....
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    Post  Cyrus the great on Sat Aug 10, 2019 2:22 pm

    GarryB wrote:A critical point regarding safety is that if you have a HE round inside a tank loaded in an auto loader system it needs to have a fuse system.

    Something that will make the main HE charge go boom.

    The problem is that generally to make HE go boom you need low explosive.

    You need a boom to get a boom from a high order explosive.

    The problem for a tank that has been hit is that all its HE rounds... including HEAT rounds as well, is that if you set fire to a HE round the HE will actually just burn and be less of a problem than propellent actually.

    It is the fuse that contains a low explosive like gunpowder that readily explodes that will set off the main charge that is the problem because if the fuse catches fire or is heated beyond a certain rather low temperature then when it explodes it will set off the main HE charge explosion, which in turn will set off other HE and HEAT rounds nearby and of course any propellent in one big explosion.

    Without the fuses a stack of HE shells will just burn for quite some time... the temperature would need to get to rather high levels before it actually explodes.

    Having a microwave system of setting off the propellent and an electric fuse for setting off the explosives on impact greatly reduce the risks in handling the rounds and in case the vehicle is hit.

    Of course even diesel will explode when it gets heated to a high temperature, but removing the propellant and keeping it separate from the ammo should make it much safer.

    Equally with Sabot rounds in the turret bustle... you could offset their positions so their sabots overlap and greatly reduce the space they take up as they wont need to be surrounded by propellent... in fact it would be better if they didn't have propellent around them to make them lighter and more compact in storage.

    Generally modern Sabot rounds have bore width petals at the front and the back to align the projectile with the barrel but in between they can be as narrow as the round itself... about 60-80mm for a projectile about 40-50mm across, so you could stack them so that they interlock and you should be able to get quite a few in there.

    BTW from memory I think the Burlak turret bustle autoloader had 31 positions for rounds... projectiles and propellent stubs... one in front of the other in each tube so the 31 tubes would have 31  projectiles and 31 propellent stubs. This new design with liquid propellent could do away with the propellent stubs and just have perhaps 32 APFSDS rounds of about half the bustle length but the same width.

    Regarding the location for the propellent if you separate it into two separate liquids that are relatively inert on their own you could create layers inside the armour with cells of the different propellent types... say 8 separate fuel compartments in the front of the hull... upper and lower... so that any penetration wont take out all of one propellent component... and it would act like spaced armour rendering rounds like HESH useless.  

    Then of course having the other component in the rear of the hull in the position between the turret and the engine where the upgraded T-90 carries an extra 6 rounds of ammo... a tank there with tubes to pump it into the gun chamber and perhaps secondary tanks in each side of the turret bustle for redundancy... turn the turret forward and pump 20 litres or so into the turret tanks... you could even put the tanks under the commander and gunners seats moving around with the turret so with fixed pipes from the seats to the rear of the gun... with further pipes leading from the rear bustle to the gun where the two chemicals are mixed and prepared for firing...

    The liquids would not necessarily be pleasant, but separately they might not even burn let alone explode.

    You might mix 300mls of one liquid with 1,000mls of the other for a high energy APFSDS round shot, whereas HE and HEAT rounds might only need 100mls of one liquid and 600mls of the other... depending on the condition and the situation the computer could probably alter the mix to improve performance in different situations...

    When reloading the tank you could have an external cap to load into the hull and turret tanks rather quickly... make the hose connectors specific to the tank so mistakes are not made... but even hosing the wrong material into the wrong tank it would still need to be microwaved to work properly....  

    OMG, Garry

    There is really nothing I can add to your response... it's perfect. I really do appreciate the lengths you have gone to in explaining how this could be put into place. Thanks, mate.
    GarryB
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    Post  GarryB on Sun Aug 11, 2019 5:07 am

    Well two things... first of all, this is mostly speculation from a guy who has spent the good part of his life reading about military stuff... I have a serious interest but I am no expert.

    Second you mentioned balance regarding the T-90M turret... actually a turret bustle would be good for it because at the moment with that big long gun sticking out and some quite heavy front turret armour it is already a bit nose heavy with regard to the turret itself.

    Adding a bit on the back with perhaps angled armour protection to protect it from light cannon rounds and slap 50 cal rounds, you could use the extra top space for a remote weapon station on the back, or more munitions for your APS system or perhaps a 40mm grenade launcher like the BMP-2 upgrade where the grenade launcher is fixed facing forward and can elevate up and down and rotates with the turret so the gunner or commander can aim and fire it... if it was put on the gunners side of the bustle it would not be in the way of the commanders pano sight and the entire bustle area to the side of the grenade launcher could be a huge ammo box for 4-500 grenades ready to fire.

    Explosives take the line of least resistance... so if you put an explosive outside a tank the armour will direct most of the explosion back on itself... you have to focus the explosive (HEAT) or just use a huge amount (250kg aerial bomb) to defeat the armour. Inside a tank the armour actually works against you because instead of deflecting the explosion away, it contains it and reflects it around inside the tank multiplying the force of the explosion by repeating it several times.

    A hand grenade outside a tank is nothing to worry about... especially with the optics ports covered by their covers. A hand grenade inside the tank could kill everyone and start a fire or a simpathetic explosion that destroys or burns out the tank.

    The top of the grenade bin can be design to have blow out panels... in fact they could be hinged to make loading grenades much easier, so if they are hit the sheet metal container will increase the force of the explosion but not enough to penetrate the bustle and certainly not enough to injure the crew in the crew compartment... it would be quite a display, but just result in no more 40mm grenades.

    Of course you ask... why bother with a grenade launcher... you are in a tank...

    Well the same reason they fitted a 30mm grenade launcher to a BMP-2 that already has a 30mm cannon.

    On paper it would make more sense to just forget the grenade launcher and just use the space for more main gun ammo, but the grenade launcher adds something new and useful.

    An example would be the Merkava tanks Israel was using... they carried a 60mm mortar with them to launch flares to operate at night.... flares are brilliant (literally) because they light up the area where the bad guys are but you remain in the dark so you can see them and make it much harder for them to see you because you are in the dark looking into the light and they are in the light looking into the dark. Well it wasn't long before they started carrying HE bombs for those mortars because sometimes you don't need a 105mm shell to do the job and you can carry lots of 60mm bombs in the space of one tank shell... but most of all if the targets are hiding behind cover a high velocity weapon like a tank gun has to shoot through a wall or other cover, whereas a mortar or grenade launcher can lob rounds over the cover and kill the people hiding behind.

    The same with the 30mm grenade launcher and the 30mm cannon shells... the 30mm grenades not so much but the new 40mm grenades carry a lot of HE and would probably have a better effect on target than a 30mm cannon shell... individually.

    For the tank the new 40mm grenade launchers have a range of 2.5km which makes it useful well beyond the range of the PKT and even the Kord... accuracy wont be amazing but the explosive nature of the grenades means a burst of 4-5 rounds should be plenty for a target like a Javelin team...

    Obviously BMP-3 units will have 100mm HE rounds for the job out to 7km and with their new 57mm guns... high velocity and grenade launcher, they should have direct and indirect HE firepower out to 12km or so for the HV gun and perhaps 6km for the grenade launcher... which would be plenty too.

    Obviously seeing targets is the problem, but there is no point if you can't reach them...

    If you spot a Javelin team at 2km range a spatter of Kord rounds might upset them, but the chance of actually killing them would be low, and that would be out of the range of the PKT too, so you only have 125mm HE rounds... which will certainly do the job, but you wont be carrying a lot of those.

    In comparison a 40mm grenade launcher on the turret bustle with 400 rounds, you could burst fire 10 rounds and either kill them or scare them half to death...

    They might be on top of a building popping their heads over to look at you... landing grenades on the roof makes more sense than trying to blow down the building...

    Equally half way up a mountain with a hand built rock wall to hide behind... lobbing HE grenades over makes more sense than trying to shoot through it... if they are far enough back from the wall even hitting the wall with a 125mm round will be bad for the wall but they might survive... a delayed fuse HE round that penetrates through and explodes on the other side would be interesting though...

    The point is that the grenades will come in near vertical with a good fragmentation pattern and is cheap and you can carry a lot of grenades for it without putting the crew at risk.

    You might not even use it... in which case you could change the grenades to CS gas or illumination or anything you want... you could even try for a 57mm grenade launcher with much longer range and HE power with perhaps 200 rounds...  (the description of the 57mm grenade launcher is that it is as powerful as a 76.2mm gun in terms of HE... which is about 6kgs of HE... per grenade... which is pretty impressive.)

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