Military Forum for Russian and Global Defence Issues


    BMPT programme

    Share
    avatar
    Isos

    Posts : 2436
    Points : 2430
    Join date : 2015-11-06

    Re: BMPT programme

    Post  Isos on Wed Jan 31, 2018 12:25 am

    What do you guys think of a new high velocity 76 or 100 mm gun for a new hybrid ligh tank based on t-15 without the space for soldier but with more protection ?

    There are more and more better armoured IFV in countries around Russia so it could act like a light vehicle/IFV chaser. Tanks are not the most used vehicle in the west, they often rely on less armoured but more mobile vehicles.

    None of them could survive a 76 or 100 sabot or HEAT round and it could even damage badly MBTs from behind or from the sides. They will have more rounds to fire than the actual number of missiles they carry so more targets destroyed per vehicles.

    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Wed Jan 31, 2018 2:00 am

    Finally you only have a float left to hold, that is the numbers from Tula's site. However, when the numbers (recoil forces) can not explain the contradictive reality, I have reasons to double they have purposely twisted the numbers or mixed oranges with apples in the same box to fool poor readers.

    For 2A42 and 2A72 guns, the reality of using 2A72 to upgrade old vehicles that could only installed 14.5mm gun before and to equip newly produced light and super-light combat vehicles has shown who is wrong, who is right about recoil of 2A72 gun  vs. 2A42 gun.

    And the "superior" (accoding to many military experts) BMPTs "project 781" used double 2A72 gun unstead of 2A42 gun like the "inferior/looser" (also accoding to many military experts) Terminator-2.

    Another very clear example that no one can not deny is the 125mm 2A75 gun of Sprut-SD light tank. It uses the long-recoil (700 mm) to reduce the significant recoil force compare to the 2A46M gun (recoil 300 mm) of heavy T-72/80/90 tanks.

    About 2A38 gun, you are totally wrong. It use completely gas-operation, gas from this barrel when firing will push the piston, powering the loafing mechanism of the other barrel. The pistons when moving back will help to reduce the recoil force (as Newton formula I mentioned in previous post).

    Conclusion:

    Aaccording to Newton formula about reservation of momentum, the gun recoil will depend on:

    - The weight and muzzle velocity of projectile.
    - The weight of gun's parts that move back when firing (barrel, etc)
    - The distance of moving back.

    This explain clearly the reasons why the recoil of 2A72 gun is just ~ 1/10 of 2A42 gun:

    - The weight and muzzle velocity of projectile is the same (04 kg and 960 m/s).
    - Its moving distance is 10 times higher than 2A42 gun's (330 mm vs 30-35 mm).
    - The weigh of gun's moving parts (barrel, bolt, etc) supposed to be quite the same with 2A42 gun's (36++ kg vs 38.5 kg).
    avatar
    GarryB

    Posts : 18555
    Points : 19111
    Join date : 2010-03-30
    Location : New Zealand

    Re: BMPT programme

    Post  GarryB on Wed Jan 31, 2018 4:03 am

    What do you guys think of a new high velocity 76 or 100 mm gun for a new hybrid ligh tank based on t-15 without the space for soldier but with more protection ?

    You need to look at targets on the battlefield and see what is needed to deal with problems... one example is the early multi turreted tanks that had a low velocity 76.2mm gun for HE power and small calibre 37mm or 45mm cannon to penetrate the thin armour of the time.

    The standard T-34 had a medium pressure 76.2mm gun instead of a high velocity 57mm gun... at the time the Germans introduced an anti tank 50mm gun and a low velocity 76.2mm gun for their tanks.

    Why not go for a high velocity 76.2mm gun?

    High velocity guns have large shell casings and are heavy and bulky and generate lots of recoil on firing.

    If a smaller lighter gun will do the job why go bigger and heavier and more expensive than you need to.

    Why not develop 203mm guns for infantry vehicles and tanks... low velocity for IFVs and high velocity for tanks?

    the simple fact is that the 125mm gun is fine for "light" tanks... and anything armata based is not a light anything.

    The main problem with airburst ammo is its general cost... to get effective airbursts the traditional method is a very very precise time keeping component inside the projectile... that is generally rather expensive... but without extreme accuracy it will not explode where you want it to... making it rather useless... detonating directly over a trench is effective... 5m past or before the trench and it is useless.

    Using a laser beam to tell it when to explode means the expensive precise time keeping bits can be in the vehicle and completely reuseable... making the ammo much much cheaper... and if you want to use it a lot then cheap ammo is critical.

    Air burst 40mm grenades and 57mm grenades will be incredibly potent rounds on the battlefield because they both have the round capacity for a decent amount of HE and fragments and a fuse to set it off at the right time.

    The South Africans were impressed with the 30mm cannon of the BMP-2 too... it is a very good weapon... and with new ammo types that are cheap enough to actually use it will become even better...


    Another very clear example that no one can not deny is the 125mm 2A75 gun of Sprut-SD light tank. It uses the long-recoil (700 mm) to reduce the significant recoil force compare to the 2A46M gun (recoil 300 mm) of heavy T-72/80/90 tanks.

    It does not make the gun in the Sprut more accurate... it just means it can be used in a much lighter vehicle.

    The long recoil method does not reduce recoil... it reduces felt recoil by spreading it over time.

    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Wed Jan 31, 2018 4:54 am

    That is just how we explain about long recoil. The longer the moving back is, the less stronger the recoil is. Therefore, the correct should be "it reduces felt recoil by spreading it over the moving back".
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Wed Jan 31, 2018 5:09 am

    kopyo-21 wrote:Finally you only have a float left to hold, that is the numbers from Tula's site. However, when the numbers (recoil forces) can not explain the contradictive reality, I have reasons to double they have purposely twisted the numbers or mixed oranges with apples in the same box to fool poor readers.

    And the authors of the technical manual for the 2A72 wanted to deceive the poor soldiers as well? Good theory.

    BTW I love how you basically just ignored everything I said. So according to you, a 2A42 only has a little more recoil than a .50 caliber sniper rifle without a muzzle brake (30-40 kN vs 33 kN) Laughing


    For 2A42 and 2A72 guns, the reality of using 2A72 to upgrade old vehicles that could only installed 14.5mm gun before and to equip newly produced light and super-light combat vehicles has shown who is wrong, who is right about recoil of 2A72 gun  vs. 2A42 gun.

    Yeah. Right.



    Amazingly, Muromteplovoz engineers have achieved an impossible task long ago. Bravo!



    Watch a BTR-80 with a 2A42 fire:



    Even a BTR-60 can have a 2A42:



    An OT-64 SKOT can have a 2A42 as well. Its technical characteristics are the same as the BTR series, and weighs 13 tons like the BTR-80.




    The 2A72 cannon, due to the use of a moving barrel scheme, transfers to the roof of the armored object a more extended recoil momentum, which means it has a smaller maximum recoil force, which makes it possible to use it on light armored vehicles such as BTR-82, Tigr- M with armored corps made of sheets with a thickness of only about 7mm, on which the use of armament more powerful than the 14.5 mm KPVT machine gun before the appearance of the 30mm gun 2A72 was previously impossible

    This is so obviously wrong that it's hilarious. The roof of the BMP-1 is 6mm thick, and the roof of the BMP-2 is also 6mm thick, and yet, both can have a 2A42 installed. Take the Turra 30 turret, for example. And what about that BMP-1-30 with a BMD-2 turret?



    Don't forget that the BMD-2 itself is incredibly light. It is 8.22 tons combat loaded with full ammo, full fuel, oil, etc. Uran-9 weighs 10 tons. Please, try to tell everyone that BMD-2 is not a "super light combat vehicle". Moving on: The roof of the PT-76 is 6mm thick. They can install a 2A42 on it too.



    What about a BTR-50P? No problem.



    Oh, and look, an MT-LBu firing a 2A42! As we all know, MT-LBu is a heavy combat vehicle Laughing BTW, those shot groupings are really nice. Another case of "more recoil force=less accuracy", I'm sure you will agree...  Laughing



    Another one, this time a BPM-97:



    BPM-97 weighs 10 tons. ~3 tons less than a BTR-80, and the same weight as an Uran-9. What is your criteria for "super light" anyway?  Laughing

    2A42 installed in K-4386 Typhoon-VDV, which weighs 13.5 tons - same as BTR-80. Looks like Russian engineers are defying your words each day.



    Nimr MECV, a humvee sized patrol vehicle:



    AMX-13 APC:



    There are more offerings by various manufacturers. CM30 one-man turret with 2A42 for BTR-60/70/80, DVK-30 for the BTR-70/80, and Burevestnik's 30mm RCWS designed for Typhoon.

    Heck, even a 2.5 ton AU-220M turret with a 57mm gun can be installed on a BTR-80. The nonsense about the 2A72 being some kind of wonder weapon that can transform an APC with 14.5mm machine gun into an IFV with a 30mm cannon because of its miraculous long recoil system (that can give 30mm cannon less recoil force than KPVT, apparently) is just that - nonsense, rubbish advertising, horseshit marketing lies, bullshit falsehoods, and so on. I think you understand. At least, I hope that you understand.



    Please stop saying things that are obviously wrong, and you won't be wrong. It's very simple Sad


    And the "superior" (accoding to many military experts) BMPTs "project 781" used double 2A72 gun unstead of 2A42 gun like the "inferior/looser" (also accoding to many military experts) Terminator-2.

    "Better" in what way? 781 had two independently traversing turrets. That is probably better than one turret. The chassis and hull was also different from what we see today. Was that better? Who knows? I'm pretty sure you don't know either, unless you have some juicy insider information to tell us. Unless the 2A72 was specifically mentioned to be better than the 2A42, you are basically making a huge leap of faith with that assumption.


    Another very clear example that no one can not deny is the 125mm 2A75 gun of Sprut-SD light tank. It uses the long-recoil (700 mm) to reduce the significant recoil force compare to the 2A46M gun (recoil 300 mm) of heavy T-72/80/90 tanks.

    This may be surprising to you, but all cannons use long recoil hydraulic recoil mechanisms. Increasing the recoil distance does decrease the recoil force. The only question is how long the recoil distance is for the 2A72. As I said before - and you did not listen, and you will not listen - the barrel is stopped in a distance of 60-65mm by the shock absorber. Oh, it's not true? Wow, they really love lying to their mechanics, technicians and soldiers, don't they! They really don't care if the people who have to work with and maintain these guns understand them!


    About 2A38 gun, you are totally wrong. It use completely gas-operation, gas from this barrel when firing will be used push the piston, powering the mechanism of the other barrel. The pistons when moving back will help to reduce the recoil force (as Newton formula I mentioned in previous post).

    Read what I wrote again. Or maybe you don't understand what a Gast gun is?


    Conclusion:

    Aaccording to Newton formula about reservation of momentum


    How does a muzzle brake reduce recoil force? Magic? Let me give you a hint: the gasses that comes out of a gun barrel have momentum and energy

    I apologize to everyone for this photo dump, but when someone is wrong, they are wrong. Reality does not change at a whim, and physics does not is physics whether you like it or not.

    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Wed Jan 31, 2018 7:34 am

    Somethings to answer your questions:

    1. 2A72 gun's barrel moves back 330 mm after firing. The 2A42 gun's barrel moves back 30-35 mm after firing.

    2. Your owned copy "2A38 is a two barrel gun that works on the Gast principle, meaning that the recoil from one barrel operates the action of the other barrel" is still there.

    You are totally wrong. The 2A38 gun's barrel are fixed so can not use the term "recoil" here. The correct must be "2A38 is a two barrel gun that works on the Gast principle, meaning that the gas blowing back from one barrel operates the action of the other barrel".

    3. You posted a lot of photos so please show me which ones are already bought and in services now. Or they are just prototypes for showing off and no one buy finally? For example, show me how/where is the BTR-82A1 with 2A42 gun now?

    Do you need me bomb photos of light combat vehicles with 2A72 that have veen bought and in services now?

    4. Muzzle brake: Do you not understand this very simple and need me to explain it for you?
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Wed Jan 31, 2018 8:48 am

    kopyo-21 wrote:

    1. 2A72 gun's barrel moves back 330 mm after firing. The 2A42 gun's barrel moves back 30-35 mm after firing.

    If I throw a rock at a cushion that is 10 m away from me, and the rock stops in the cushion after penetrating 0.1 m, did the rock take 10.1 m to decelerate to a stop, or did it take 0.1 m to decelerate down to a stop? (Ignore air resistance) Come on, think! You can do it! I believe in you!

    BTW I really love how your story changed.

    When firing, most of 60KN recoil force will be used to power the gun system so the recoil left 6KN on the turret finally (as my source mentioned)

    In the opposite way, the 2A42 guns mainly use the gas from the cartridge power burning to operate the gun system. When firing Its recoil according to Tula's is 50-60KN. The 30-40KN as mt source mentioned should be the recoil left on the turret finally.

    So you started off saying that Tula's given number of 60 kN of 2A72 is reduced to 6 kN, and 40-50 kN of 2A42 gets reduced to 30-40 kN. Tula's data is the raw recoil force without including the muzzle brake, and weaponsystems.net's data is the final recoil force with a muzzle brake. Then you said that the muzzle brake of the 2A42 is responsible for the lower (40-50 kN vs 60 kN) recoil force compared to 2A72.

    It is very simple and no need to talk too long & too much. The 2A42 and the 2A72 fire the same rounds, have the same barrel length and barrel design so basically, according to Newton, they will produce the same recoil force. According to Tula's data, the 2A42 guns produce less recoil than 2A72. This simply because of muzzle brake on 2A42 but 2A72.

    So Tula's data already includes the muzzle brake in this new story  Very Happy At first, it was 40-50 kN gets reduced to 30-40 kN. Then 2A42 suddenly has the same recoil force as 2A72, so now it is 60 kN gets reduced to 30-40 kN.

    After you did your little calculations, you switched course and changed your stance entirely:

    Finally you only have a float left to hold, that is the numbers from Tula's site. However, when the numbers (recoil forces) can not explain the contradictive reality, I have reasons to double they have purposely twisted the numbers or mixed oranges with apples in the same box to fool poor readers.

    Now you're saying that Tula is giving false numbers.

    Conclusion: You are a clown. Your argument is inconsistent, self-contradictory, and inconsistent with real data. You are making this up as you go along  Wink


    kopyo-21 wrote:
    2. Your owned copy "2A38 is a two barrel gun that works on the Gast principle, meaning that the recoil from one barrel operates the action of the other barrel" is still there.

    You are totally wrong. The 2A38 gun's barrel are fixed so can not use the term "recoil" here. The correct must be "2A38 is a two barrel gun that works on the Gast principle, meaning that the gas blowing back from one barrel operates the action of the other barrel".

    Now I know why you ignore huge chunks of my posts. You are blind!

    You must read this part that I wrote about the 2A38:

    In this case, the gasses from the first barrel pushes first bolt assembly backwards and compresses the recoil spring, and the first bolt assembly pushes the second bolt assembly forward using a rack and pinion system.

    Like in all the other cases, you only saw what you wanted to see. Yes, I did write "recoil", and then I followed up with an explanation about what it meant in the case of the 2A38. You really have to stop trying to bend reality. It doesn't work.

    kopyo-21 wrote:
    3. You posted a lot of photos so please show me which ones are already bought and in services now. Or they are just prototypes for showing off and no one buy finally? For example, show me how/where is the BTR-82A1 with 2A42 gun now?

    Do you need me bomb photos of light combat vehicles with 2A72 that have veen bought and in services now?

    You were just shown that it was in fact possible to mount 2A42 on the BTR-80 and other light vehicles, and you were shown that a BTR-80 with a 2A42 was able to fire on the move when you said that it was not possible, and now you are trying to change the topic because you were proven to be completely wrong:

    If they want to keep the firing accuracy while on stop and while on move, they will have to reinforce gun mounting, turret, hull and chassis. In that case, the vehicles will gain a significant weight that may ask for changing engine, reducing the protection level, etc.

    Of course, no such thing was required. You saw the video of a BTR-80 with a 2A42 firing on the move. The turrets offered by Muromteplovoz and other companies are drop-in turrets that require no prior modification to the vehicle. Whether these turrets are widespread is another matter entirely. If, according to you, large recoil forces from 2A42 reduces its accuracy because it's mounted on such light vehicles, it still won't be as bad as a 2A72 that was mounted on a BTR-80A and BTR-82A without a barrel support, which goes against all logic. You yourself gave a quote that said the same thing:

    The fee for using the scheme with a movable barrel was a somewhat worse accuracy

    So why did they mass-produce the 2A72 for the BTR-82A without a barrel support when the 2A72 on the Uran-9 and Tigr-M have barrel supports? Accuracy definitely wasn't a priority, it appears. As to whether or not these 2A42 turrets are used at all: best example is the BMD-2. It is very common, and it is the lightest vehicle among all of the light vehicles you mentioned, including the Uran-9. Also, Typhoon-VDV is lighter than the BTR-82A, and it's a 4x4 so it's a light combat vehicle by any reasonable criteria. Some other turrets like the DVK-30 have not yet received any contracts, but it's most likely because it has an externally mounted Fagot/Konkurs missile launcher, and the gunner has to come out of his hatch to use it. That would be a dealbreaker, of course. There are many factors that go into such things, but the important thing is that it is in fact more than possible to install a 2A42 on light vehicles with a roof of 7mm or even 6mm. Once you acknowledge this fact, you can move on with your life.

    kopyo-21 wrote:
    4. Muzzle brake: Do you not understand this very simple and need me to explain it for you?

    No, you must explain it to me, unfortunately. So according to you:

    30x165mm (fixed barrel, no muzzle brake): 60 kN
    12.7x99mm (fixed barrel, no muzzle brake): 33 kN

    You see, a muzzle brake can reduce the recoil of a rifle or a cannon by 70-80% according to The Basics of Artillery Guns and Ammunition by A.Y Derevyanchuk. Why you think that the Russians are so stupid that a muzzle brake + a recoiling barrel can only reduce the recoil force of a 2A42 from 40-50 kN to 30-40 kN or even 60-62 kN to 30-40 kN is a mystery to me, because that is only a 20-25% reduction in recoil force, ~50% at the max if we assume that your earlier calculations for 2A42=62kN are correct. Also, you know what a muzzle brake is, so you must know that it uses the energy and momentum from the propellant gasses to push the rifle/cannon forward to reduce rearward recoil, yes? So you realize that propellant gasses have energy and momentum. Then why do you ignore it?

    Anyway, that's not the point: 33 kN from a TAC-50 is only reduced to 6.6 kN by a high efficiency muzzle brake (80% reduction in recoil force) at the most. McMillan offers an R2 hydraulic recoil mitigation system that reduces this further to 2.3 kN, but regular TAC-50 rifles do not have the R2 hydraulic recoil mitigation system, just a muzzle brake. So basically, if you had a regular TAC-50 with only a muzzle brake, it would produce 6.6 kN of recoil force and people can fire it on their shoulders without any injury or even discomfort. That means that the 2A72 with 6 kN of recoil force can be fired from the shoulder or from a bipod as well.

    According to your logic:
    2A72: 6 kN
    TAC-50: 6.6 kN

    I wish I could go to your house, so that you can look me in the eye with a straight face and say it out loud: "Recoil force of 2A72 is less than .50 caliber sniper rifle with muzzle brake". Laughing Laughing Laughing Laughing Laughing Laughing Laughing Laughing I swear, you should either be on a stage or in a mental hospital.
    avatar
    George1

    Posts : 12166
    Points : 12645
    Join date : 2011-12-22
    Location : Greece

    Re: BMPT programme

    Post  George1 on Wed Jan 31, 2018 1:27 pm

    Russian machine builder vows to fulfill deliveries of Terminator AFVs by early 2019

    The Russian Defense Ministry signed a contract to deliver Terminators during the Army-2017 forum

    MOSCOW, January 31. /TASS/. The implementation of the contract to deliver Terminator tank support armored fighting vehicles will be completed in early 2019, and the army will get the first batch in March -April 2018, the Research and Production Corporation Uralvagonzavod told TASS.

    "It [the contract - TASS] is long-term. We plan to deliver the first batch of the tank support fighting vehicles this March - April. The whole contract will be completed by early 2019. The volume of deliveries is confidential, but overall it provides for the organization of operational testing for these specified products," the corporation said.

    Chief of the Main Armored Directorate of the Russian Defense Ministry Lieutenant General Alexander Shevchenko earlier said that the Terminator AFV would become operational in 2017. He noted that "this is a brand-new class of vehicle" "that many countries, chiefly Israel and Syria, are interested in." The general specified that the AFV had successfully passed all test operations.

    The Russian Defense Ministry signed a contract to deliver Terminators during the Army-2017 forum. The agreements that the defense ministry and Uralvagonzavod inked then are worth over 24 bln rubles ($426.3 mln) The Terminator has a 44-tonne combat weight, according to the producer’s website. The vehicle is outfitted with two 30-mm-caliber 2A42 automatic guns and 7.62-mm-caliber PKT coaxial tank machine gun.


    More:
    http://tass.com/defense/987812

    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Thu Feb 01, 2018 1:33 am

    @ Interlinked

    Posts after posts, they become not only my logic and the reality but also the calculations that follows the Newton's momentum conservation. You write a lot, provide a lot of your assumption to avoid facing with both physics laws and reality:

    1. Physics laws:  According to the Newton's momentum conservation law, both 2 guns 2a42 and 2a72 fire same bullet (0.4 kg) with the same muzzle velocity (960 m/s) so right after the bullet leaving the barrel, both 2 guns must whistand the same momentum back (initial recoil).

    Besides that, also right after the bullet leaving the barrel, the burning gas throut out from the gun muzzel makes gun like a rocket and the second recoil appears. Both 2 guns fire the same rounds (the same cartridge powder), have the same barrel length and groves design so their secondary recoil are the same.

    However, the  2A42 gun use the muzzle brake that helps to reduce the secondary recoil therefore its total recoil is lower than 2A72 at the moment the bullet leaving the barrel. (Don't make your owned assumption about the muzzle brake of 2A42 gun reduces 90% of recoil force)

    I wrote so long like that to explain you and prove why I said both 2 guns produce the same recoil when firing but the muzzle brake makes the total recoil of 2A42 lower than 2A72

    Also according to the Newton's momentum conservation law, right after receiving the recoil, both 2 gun's barrels move back to balance the force. It reduces the recoil by spreading it over the moving back so the longer moving back is, the lower force needed to stop is.

    The 2A72 gun's barrel moves back 330 mm, much more (around 10 times) higher than the 30-35 mm of 2A42 gun's barrel so it spreads out the recoil much more effectively (around 10 times as calculation) than 2A42 gun. Therefore when the barrels stop (after 330 mm in 2A72 and after 30-35 mm in 2A42), the force that 2A72 gun's barrel push on the gun is much less than 2A42 gun's barrel do.

    "To reduce the impact of the gun's release, the barrel is absorbed and recedes 30 to 35 mm when firing."
    http://www.arms-expo.ru/armament/samples/1300/59779/

    Comparison with the 2A42 gun: The 2A72 cannon, due to the use of a moving barrel scheme, transfers to the roof of the armored object a more extended recoil momentum, which means it has a smaller maximum recoil force, which makes it possible to use it on light armored vehicles such as BTR-82, Tigr- M with armored corps made of sheets with a thickness of only about 7 mm, on which the use of armament more powerful than the 14.5 mm KPVT machine gun before the appearance of the 30mm gun 2A72 was previously impossible..
    http://www.history147.ru/2017/09/blog-post.html?m=1

    "The 2A72 cannon, due to the application of the scheme with a movable barrel, transfers a more extended recoil momentum to the roof of the armored object, as compared to the gas escape line on 2A42, and therefore has a smaller maximum value of the instantaneous recoil force (7 tons versus 20 tons for 2A42 with fixed barrel)"
    https://ru.m.wikipedia.org/wiki/30-мм_пушка_2А72

    "The 2A72 cannon, due to the application of the scheme with a movable barrel, transfers a more extended recoil momentum to the roof of the armored object, as compared to the gas escape line on 2A42, and therefore has a smaller maximum value of the instantaneous recoil force (7 tons versus 20 tons for 2A42 with fixed barrel), which allows use it on light armored vehicles such as BTR-82, Tigr-M with armored corps made of sheets with a thickness of only about 7 mm, on which the use of armament more powerful than the 14.5 mm KPVT machine gun before the appearance of 30mm gun 2A72 was previously impossible."
    https://wikivisually.com/lang-ru/wiki/2А72

    PS: I give all of suorces above not for the "7 tons" and the "20 tons" numberd as I can not determine where are come from. Just want to re-confirm that the 2A72, thank to its longer-recoil operation, has push much lower force on the turret and whole vehicles than the 2A42 do.

    2. The reality: Sofar, all projects that upgrade or newly produce wheeled combat vehicles that have been bought by both domestic and oversea like BTR-80A, BTR-82A, BTR-3/4 in Russia and Ukraine have been using 2A72 instead of 2A42. In contrasts, no one has bought vehicles with 2A42 gun like BTR-90, BTR-82A1, etc.

    PS 1: BTW, you should revise the data about firing accuracy of 2A42 in your blog. The given data is totally incorrect that may makes you and your readers percept wrongly not only about 2A42 bust also about 2A72.

    PS 2: The 2A42 is nothing better than the 2A72 (with barrel's rigid sleeve support) but only ROF.

    PS 3: In the contrasts, the 2A42 is bigger, more expensive, smockier and much more recoil than the 2A72.

    PS 4: Sofar, you still can not prove anything that you use to fight back my points, suggest replacing the 2A42 by 2A72 on new generation of BMPT.
    avatar
    GarryB

    Posts : 18555
    Points : 19111
    Join date : 2010-03-30
    Location : New Zealand

    Re: BMPT programme

    Post  GarryB on Thu Feb 01, 2018 6:11 am

    The primary purpose of the 2A72 was to eliminate the problem of fumes in the turret of the BMP-2.

    As fumes are not an issue for helicopter mounts or the new generation of armoured vehicles which have unmanned turrets I fail to see the advantages of the 2A72... especially now at a time where most of its applications are being replaced by larger calibre weapons.

    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Thu Feb 01, 2018 6:28 am

    Just read an artical on BTVT that reconfirms that, each gun of 2A42 on BMPT-72 is feeded 1 type of rounds, either HEI or API, and fired in turn instead of mixed rounds and fired simultaneously.

    Both 2 2A42 gun are hang either off-right or off-left of turret axis so when only 1 gun fires, it will tend to spin the turret due to its very strong recoil. In that case, the firing accuracy is a big question.

    http://btvt.info/1inservice/tom3_bmpt_weapon.htm

    PS: The BMPT project 781, that was much highly evaluated by many military experts than the current BMPT-72, chose using double 2A72 gun instead 2A42 gun.



    Last edited by kopyo-21 on Thu Feb 01, 2018 6:51 am; edited 1 time in total

    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Thu Feb 01, 2018 6:37 am

    GarryB wrote:The primary purpose of the 2A72 was to eliminate the problem of fumes in the turret of the BMP-2.

    As fumes are not an issue for helicopter mounts or the new generation of armoured vehicles which have unmanned turrets I fail to see the advantages of the 2A72... especially now at a time where most of its applications are being replaced by larger calibre weapons.
    The smocky issue may be the primary reason they created the 2A72. However, if we think about the 2A72 gun is installed off-right of BMP-3's turret axis, the recoil may be also the primary reason.

    Nowaday, it has shown the "less smock" is just one of some 2A72 gun's advantages that help it more suitable for light/small combat vehicles.

    - Much less recoil.
    - Smaller.
    - Cheaper.

    Don't forget that the 2A72 was created after the 2A42 and by the same team so I have reason to believe that it was designed with issues of 2A42 in mind.
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Thu Feb 01, 2018 8:32 pm

    kopyo-21 wrote:
    Posts after posts, they become not only my logic and the reality but also the calculations that follows the Newton's momentum conservation. You write a lot, provide a lot of your assumption to avoid facing with both physics laws and reality:

    Laughing

    kopyo-21 wrote:
    1. Physics laws:  According to the Newton's momentum conservation law, both 2 guns 2a42 and 2a72 fire same bullet (0.4 kg) with the same muzzle velocity (960 m/s) so right after the bullet leaving the barrel, both 2 guns must whistand the same momentum back (initial recoil).

    Besides that, also right after the bullet leaving the barrel, the burning gas throut out from the gun muzzel makes gun like a rocket and the second recoil appears. Both 2 guns fire the same rounds (the same cartridge powder), have the same barrel length and groves design so their secondary recoil are the same.

    You acknowledge the rocket effect of propellant gasses, and then you don't care about it. In your calculations, you used the momentum of the 0.4 kg projectile, and then ignored the propellant gasses entirely... You like to talk about "law of Newton" and "physics laws" when it suits you, and then you ignore them when they are inconvenient. You do this because you know that when you add the propellant gasses into the equation, the recoil force jumps from 6.2 kN to something much, much higher... and your illusion is shattered. So of course, you prefer to pretend that it does not exist  Wink

    kopyo-21 wrote:
    However, the  2A42 gun use the muzzle brake that helps to reduce the secondary recoil therefore its total recoil is lower than 2A72 at the moment the bullet leaving the barrel. (Don't make your owned assumption about the muzzle brake of 2A42 gun reduces 90% of recoil force)

    I wrote so long like that to explain you and prove why I said both 2 guns produce the same recoil when firing but the muzzle brake makes the total recoil of 2A42 lower than 2A72

    Also according to the Newton's momentum conservation law, right after receiving the recoil, both 2 gun's barrels move back to balance the force. It reduces the recoil by spreading it over the moving back so the longer moving back is, the lower force needed to stop is.

    The 2A72 gun's barrel moves back 330 mm, much more (around 10 times) higher than the 30-35 mm of 2A42 gun's barrel so it spreads out the recoil much more effectively (around 10 times as calculation) than 2A42 gun. Therefore when the barrels stop (after 330 mm in 2A72 and after 30-35 mm in 2A42), the force that 2A72 gun's barrel push on the gun is much less than 2A42 gun's barrel do.

    "To reduce the impact of the gun's release, the barrel is absorbed and recedes 30 to 35 mm when firing."
    http://www.arms-expo.ru/armament/samples/1300/59779/

    Just because the barrel moves back by 330-335mm does not mean that it decelerates at the same rate throughout. Here's what the technical description (Техническое описание и инструкция по эксплуатации 30-мм автоматической пушки 2А72.00.000.TO) for the 2A72 says:

    При выстреле ствол вместе с затвором под действием пороховых газов на дно гильзы движется назад.

    Ствол с затвором первоначально движется назад свободно сжимая возвратную пружину.

    Пройдя=270мм начинают сжимать пружину аммортизатора. Сжав ее на 60-65мм энергия отката ствола поглощается, и они останавливаются.


    Translation:

    When a shot is fired, the barrel, together with the bolt, moves backward under the action of the powder gases on the bottom of the cartridge case.

    The barrel with the bolt initially moves backwards freely compressing the return spring.

    Passing=270mm begins to compress the spring of the shock absorber. Compressing it by 60-65mm, the energy of the moving barrel is absorbed, and they stop.


    You tell me, what does it say about how far the barrel needs to stop? Keep in mind that the return spring is a tiny little spring whereas the shock absorber spring is a massive coil spring that wraps around the barrel, as you can see below (2. shock absorber, 6. return spring):



    Deceleration is low when the return force is low, and deceleration is high when the return force is high. When the barrel is only compressing the tiny return spring, the barrel only loses a few meters/second in a long span of time, but when it compresses the huge shock absorber spring, it decelerates very quickly within a distance of 60-65mm. The small return spring is much smaller than the return spring for the 2A42, which has a much larger bolt carrier and bolt than the 2A72 so it needs a bigger return spring. Do you wonder why the technical description says "moves backwards freely"? It is because the barrel is barely slowing down at all before it contacts the shock absorber.

    kopyo-21 wrote:
    http://www.history147.ru/2017/09/blog-post.html?m=1

    https://ru.m.wikipedia.org/wiki/30-мм_пушка_2А72

    https://wikivisually.com/lang-ru/wiki/2А72

    PS: I give all of suorces above not for the "7 tons" and the "20 tons" numberd as I can not determine where are come from. Just want to re-confirm that the 2A72, thank to its longer-recoil operation, has push much lower force on the turret and whole vehicles than the 2A42 do.

    All these websites basically copy from ru.wikipedia, and the relevant paragraph from ru.ikipedia.ru has 0 sources. Literally 0. The page that you are quoting from was first edited by an anonymous user on the 22rd of April 2017, who added the stuff about the 7mm roof: https://ru.wikipedia.org/w/index.php?title=30-%D0%BC%D0%BC_%D0%BF%D1%83%D1%88%D0%BA%D0%B0_2%D0%9072&direction=next&oldid=85004226

    The second edit was made on June 29 and made a minor grammatical change, but it was otherwise identical. The third edit was done by another anonymous user on the 5th of September 2017, who added the "7 tons vs 20 tons" statement without listing sources. If you compare this version of the wiki article with the previous versions, there were no changes in the references list: https://ru.wikipedia.org/w/index.php?title=30-%D0%BC%D0%BC_%D0%BF%D1%83%D1%88%D0%BA%D0%B0_2%D0%9072&direction=next&oldid=86258286

    You were unable to find a source for "7 tons" and "20 tons" of recoil because those numbers were completely made up. 7 tons of recoil force is equal to 68 kN, and 20 tons is equal to 196 kN, which is absurd, of course. Just another case of article vandalism. It's pretty obvious that Wikivisually is just a website that automatically copies content from Wikipedia but with a photo gallery on the right side of the page, if you bothered to read the top right corner of the page you quoted, and the history147.ru blog article is also directly copied from Wikipedia. Compare them:

    history147 blog:
    Пушка 2А72 за счет применения схемы с подвижным стволом, по сравнению с газоотводной на 2А42 передает на крышу бронеобъекта более растянутый по времени импульс отдачи, а значит имеет меньшее максимальное значение силы отдачи, что позволяет использовать ее на легкой бронетехнике типа БТР-82, Тигр-М с бронекорпусами выполненными из листов толщиной всего около 7 мм, на которой применение вооружения мощнее 14,5мм пулемета КПВТ до появления 30мм пушки 2А72 ранее было невозможно. Это ставит, по огневым возможностям, их на один уровень более тяжелыми и дорогими БМП и значительно повышает боевую ценность легких бронемашин в обороне (когда бой ведется из окопа и уровень бронезащиты боевой машины не столь важен).

    Wikipedia edit from the 29th of June, 2017:

    Пушка 2А72 за счет применения схемы с подвижным стволом, по сравнению с газоотводной на 2А42 передает на крышу бронеобъекта более растянутый по времени импульс отдачи, а значит имеет меньшее максимальное значение силы отдачи, что позволяет использовать ее на легкой бронетехнике типа БТР-82, Тигр-М с бронекорпусами выполненными из листов толщиной всего около 7 мм, на которой применение вооружения мощнее 14,5мм пулемета КПВТ до появления 30мм пушки 2А72 ранее было невозможно. Это ставит, по огневым возможностям, их на один уровень более тяжелыми и дорогими БМП и значительно повышает боевую ценность легких бронемашин в обороне (когда бой ведется из окопа и уровень бронезащиты боевой машины не столь важен).


    Would it be a surprise to you if I told you that the history147.ru article was written on the 3rd of September, 2017? Just two days before the Wikipedia article on the 2A72 was edited on the 5th of September and the "7 tons vs 20 tons" rubbish was added, and for that reason, the history147.ru article is only identical to the Wikipedia page on the 2A72 from June 29. So in summary:


    • April 22: "7mm roof" appears on Wikipedia without references or sources of any kind

    • June 29: Minor grammatical change

    • September 3: history147.ru article copies June 29 version of Wikipedia article on 2A72

    • September 5: "7 tons vs 20 tons" appears on Wikipedia without references or sources of any kind



    The "7mm roof" claim was originally made on a Wikipedia article and has no sources, and the author of that claim was an anonymous person from Moscow, so nobody with a name is taking responsibility for it. No wonder, since it's such a stupid claim! The BMP-2 has a roof that is 6mm thick, and guess what cannon it has? This little detail allows us to conclusively confirm that all of the sources you listed are in fact direct copy-and-paste jobs taken from an unsourced Wikipedia article. Your sources get worse and worse. First it was weaponsystems.net, a website with articles written by anonymous authors and has no references or sources, and now it's Wikipedia, a website with an article written by an anonymous author that has no references or sources. This is what you're leaning on. These are your sources. This is what you're basing your entire argument on.  Laughing

    kopyo-21 wrote:
    2. The reality: Sofar, all projects that upgrade or newly produce wheeled combat vehicles that have been bought by both domestic and oversea like BTR-80A, BTR-82A, BTR-3/4 in Russia and Ukraine have been using 2A72 instead of 2A42. In contrasts, no one has bought vehicles with 2A42 gun like BTR-90, BTR-82A1, etc.

    Again you talk about this. Many products have been offered over the years, not all have entered service. It's natural. Often it's about manufacturing capabilities. Muromteplovoz makes turrets with a 2A42 that could have been used for the BTR-82A, but they also had the same turret except with a 2A72 instead of a 2A42, so they could have bought that instead. See photo:



    Why not? Maybe Muromteplovoz does not have the kind of manufacturing capacity to produce thousands of turrets. After all, they have been mostly doing overhaul work for years. Speaking of the BTR-82A, you need to realize that even though the BTR-80A, BTR-82A, and BRM-3K all have a 2A72, the barrels on their guns are unsupported. What happens when the barrel is unsupported? According to a proposal document titled Новые Технологии Создания Малокалиберных
    Автоматических Пушек
    :

    Например, в одной из работ была выбрана 30-мм пушка 2А72 широко применяемая в сухопутных войсках. Достоинством этой пушки является селективное питание и надежность. Пушка имеет низкий темп стрельбы, он составляет около 400 выстр./мин., что позволяет более экономно расходовать боекомплект. Недостатками является так называемый эффект «хлыста» – ствол при выстреле испытывает на себе мощные колебания, что приводит к резкому снижению точности при стрельбе очередью. Данный недостаток решается помещением стола в направляющие (БМД-4 и БМП-3) или сильным снижением темпа стрельбы (БТР-80А)

    Translation:

    For example, in one of the works chosen was 30-mm gun 2A72 widely used in the army. The advantage of this gun is selective feed and reliability. Gun has a low rate of fire, about 400 RPM, which allows for more economical use of ammunition. The disadvantage is the so-called "whip" effect - when a shot is fired the barrel experiences powerful vibrations, which leads to a sharp reduction in accuracy when firing bursts. This disadvantage is solved by putting the barrel in guides (BMD-4 and BMP-3) or a strong decrease in rate of fire (BTR-80A).

    Yes, what Alexander Blagonravov said is absolutely correct. Low accuracy of the 2A72 was solved by putting a barrel support, but only on the BMP-3. If a 2A72 has no barrel support, it can only be fired with a "strong decrease in the rate of fire", meaning that the cost of mounting a 2A72 in a BTR-80A/82A or a BRM-3K (recon vehicle based on BMP-3 without 2A70) is a huge reduction in accuracy that is only avoided by firing slowly or by firing in single shots only. That's why the BTR-80A has three settings for the 2A72: semi-auto, 200 RPM, and 330 RPM. It says so in the technical manual (TO BTR-80A). Also, the early prototypes of early Pantsirs were equipped with dual 2A72s (unsupported barrels) instead of 2A38Ms, and the combined rate of fire from the two guns was 440 RPM, or 220 RPM each. Given this track record of ignoring the need for a barrel support on a cannon that clearly needs it, suggesting that the 2A42s on the BMPT should be replaced with 2A72s is just irresponsible.

    Anyhow, I know you like to use the Tigr-M as an example of the "low recoil" of the 2A72, so let's ask the question of how were they able to stick a 2A72 onto the roof of a small 4x4 car: No, it's not because 2A72 has such low recoil that it can be installed on a roof that is "less than 7mm thick". It's because they had to build an intrusive structural support inside the cabin to support the turret, reducing the number of passenger seats in the cabin from 7 to just 2, as you can see in the photos below.





    On the other hand, the installation of the 2A42 in an unmanned turret in the Typhoon-VDV had a much, much less effect on the inhabitable space inside the car.



    kopyo-21 wrote:
    PS 1: BTW, you should revise the data about firing accuracy of 2A42 in your blog. The given data is totally incorrect that may makes you and your readers percept wrongly not only about 2A42 bust also about 2A72.

    PS 2: The 2A42 is nothing better than the 2A72 (with barrel's rigid sleeve support) but only ROF.

    PS 3: In the contrasts, the 2A42 is bigger, more expensive, smockier and much more recoil than the 2A72.

    PS 4: Sofar, you still can not prove anything that you use to fight back my points, suggest replacing the 2A42 by 2A72 on new generation of BMPT.


    1. Laughing

    2.  Laughing

    3.  Laughing

    4.  Laughing  Laughing  Laughing  Laughing  Laughing


    Your proposal to mount two 2A72s to replace the two 2A42s and increase the firerate of the 2A72s "with some modifications" demonstrates a total lack of understanding of the mechanism of the 2A72. The long-recoil action limits its fire rate to around 330 RPM, and the cannon fires at its maximum RPM at all times. It cannot go any faster.


    Last edited by Interlinked on Thu Apr 12, 2018 7:10 am; edited 4 times in total
    avatar
    GarryB

    Posts : 18555
    Points : 19111
    Join date : 2010-03-30
    Location : New Zealand

    Re: BMPT programme

    Post  GarryB on Thu Feb 01, 2018 10:32 pm

    If you look at the MG42 it is pretty clear how you could increase the rate of fire of the 2A72... the MG 42 has two different bolts... one heavy and one light... the different bolt weights offering different rates of fire.

    The 2A72 could easily be made to fire at a high rate of fire... simply have the barrel disconnect from the bolt during recoil so that it is only the bolt recoiling and not the bolt and the barrel.

    Of course this will lead to increased fumes in the crew compartment, but as most new turrets with 30mm cannon are unmanned that would not matter.

    Of course unsupported barrel and higher rate of fire and you would end up with poor accuracy and fumes in the crew compartment... you might as well have the 2A42.

    Personally I think replacing the two single barrel 30mm cannons on the BMPT with a twin barrel 2A38M, or the GSh-30-2 as mounted on the Hind and Su-25 would be a better solution... the high rate of fire could be compensated by with very short bursts of 1-20 rounds.
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Fri Feb 02, 2018 6:52 am

    Garry, that's not how the 2A72 works. The barrel and bolt both recoil backwards together when a shot is fired (so the total mass of the recoiling elements is actually a bit higher than 36 kg as the weight of the barrel alone would suggest). You can't increase the rate of fire of the cannon by having bolts of different weights because the bolt is already very small and lightweight, especially compared to a 2A42 bolt, and its weight is much smaller than the recoiling barrel so increasing the weight of the bolt won't increase or decrease the momentum of the recoiling elements by much, so you won't change the rate of deceleration by much. For reference, here's a 2A72 bolt:



    As you can see, it's really quite a tiny thing compared to the size of a 30mm cartridge. The bolt is cylindrical with a rotating head and four locking lugs, and the diameter of the bolt is only a few millimeters larger than a 30mm case, and it's also shorter than a 30mm cartridge. The return spring fits into a cylindrical tunnel inside the bolt, and the firing pin is there as well, so the bolt is hollow. The weight of this bolt is absolutely insignificant compared to the 36 kg barrel even if it was made from solid steel.

    The method used on the MG 42 worked on the MG 42 because the bolt was the only recoiling element, and you could have a bolt as light as 550 grams or as heavy as 950 grams. That's almost a 100% increase in mass! If you want to reduce the rate of fire, remember that you have a recoiling barrel that weighs 36 kg on its own, so increasing the mass of your ~2 kg bolt by 100% to 4 kg will only result in a total change in mass of 5.2% (40 kg total vs 38 kg total). This will also be true if you want to increase the fire rate by decreasing the mass of the bolt, which is not an easy thing to do since it's already extremely small and light. If you can somehow manage to cut the mass by half and create 1 kg bolt, you'd only be changing the total mass by 2.7% (37 kg total vs 38 kg total). Switching the heaviest bolt for the lightest bolt to cut the mass of the recoiling elements by 50% in an MG 42 can give you a 66.7% increase in fire rate (1500 RPM vs 900 RPM), but a difference of that magnitude would only effect a 2.7% difference in the total mass of the recoiling elements. That really won't change the ROF of the cannon by any noticeable amount.

    The 2A72 has a rotating bolt and no real "bolt carrier" like a 2A42 (which is basically the same as an AK-47) and no delayed recoil mechanism like the FAMAS, G3 or MG 42, because it's a long recoil gun. The bolt carrier on the bolt of the 2A72 is just the rear part of the bolt. The only part that rotates is the head, with the four locking lugs.


    Last edited by Interlinked on Thu Apr 12, 2018 7:18 am; edited 3 times in total
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Fri Feb 02, 2018 7:57 am

    Here's what happens when you fire a short burst from a 2A72 in a BTR-82A. Looks like the gunner was firing at the low rate (200 RPM) or in semi auto.


    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Fri Feb 02, 2018 8:55 am

    Look back @Interlinked. I have never ever suggested to increase ROF of 2A72 . What I said and proved was, intead of firing in turn, gun by gun like 2A42 on BMPT-72, they should improve the feeding system to have both 2A72 gun fired the same round, either HEI or API, simultaneously. In that case, total their ROF is the same with a 2A42 gun.

    As mentioned, I did not care about "7 tons" and "20 tons" number so you are waste time to focus on where they come from. You write a lot but that don't help you to create your owned phisics laws, deny the Newton's conservation of momentum laws and escape from facing with the reality.

    Your informations about 2A72 gun's mechanism, out of your intention, just help to make more clearly how it spread out its recoil over 2 stages, the first 260 mm and the second 65 mm. That help you nothing to prove your points and to refuse "the longer moving back is, the less recoil force is." You are totally wrong to think that, the spreading out recoil just starts when it barrel hit the bolt and its recoil distance is just 65 mm. The correct is, it starts spreading out the recoil when moving back and its recoil distance is 325 mm, accumulated from 260 mm and 65 mm.

    You also (can not) say nothing about the light tank Sprut-SD that use longer-recoil (700 mm) to reduce much more recoil than shorter-recoil (300 mm) 2A46M gun of heavy tanks T-72/80/90.

    Back to the 2A72 gun, there are alot bullshits floating on internet about it without supportive data. Those bullshits just come from stupid netizens who just hear the rumors here and there, and easily thrashed by someones who can not digest the reality. Back to data from 1990's, the firing accuray, both HEI and API rounds, of 2A72 guns on BMP-3 and on the BMP-1 (Clever turret) is the same with 2A42 gun on BMP-2 so it is stupid to use its firing accuracy factor to deny it.

    There are some methods to improve the firing accuracy of 2A72. The first is attaching its barrel to a rigid sleeve support like BMP-3, BMP-1 "Clever", Uran-9 and Ukrainian BTR-3/4. The other is what "VPK" LLC do with BTR-82A. Instead of using the sleeve support like others, they just decrease its ROF by realizing that, the gun's barrel needs a while to recover its designed status after each firing so just simply give it enough time to recover. Finally, the 2A72 gun on BTR-82A achieves the same firing accuracy like 2A42 gun on BMP-2. Don't forget that, the BTR-82A is wheeled and achieving the same accracy of tracked BMP-2 is not easy.

    You may not know, the BTR-82A is the first and only vehicle sofar that apply the airbrush HEI round for its 2A72 gun. Therefore, although its slower down ROF, its effectiveness is still much more than others.

    Besides beeing imposible to answer why most of successfull ligh combat vehicles in both Russia and Ukraine are using 2A72 gun instead, you also can not answer why the Chelyabinsk Tractor Plant (GSKB-2) leaded by chief designer VL Vershinsky  and the Instrument Design Bureau (KBP) leaded by chief designer A. G. Shipunov chose 2A72 guns for their BMPT project "781" instead of 2A42 guns. They all were much knowledgeable and smart enought to chose the best for their project. The guns totally were instaled outside of the hull so this time was not because of the "smocky issue" anymore.


    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Fri Feb 02, 2018 10:11 am

    GarryB wrote: high rate of fire could be compensated by with very short bursts of 1-20 rounds.
    The 2A38 gun supposed to evolve from the Gsh-30K that can fire at low ROF mode - 300 rpm. So they may still keep that mode on 2A38 gun. If not, the option of Gsh-30K is good enough and surely better than Gsh-30-2.
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Fri Feb 02, 2018 10:18 am

    kopyo-21 wrote:Look back @Interlinked. I have never ever suggested to increase ROF of 2A72 . What I said and proved was, intead of firing in turn, gun by gun like 2A42 on BMPT-72, they should improve the feeding system to have both 2A72 gun fired the same round, either HEI or API, simultaneously. In that case, total their ROF is the same with a 2A42 gun.

    You're a dumbass. You know that, right?


    4. I have the points to suggest replacing 2A42 guns by 2A72 guns on new version of BMPT . The first, 2A72 is far less recoil so will make the turret less vibration, especiall when the guns are highly mounted (like on BMPT-72) and the accuracy will be improved finally. The second, if they can improve the feeding limitation (on BMPT-72) to feed both type of rounds on each gun, they can select what round they want and fire it simultaneously at maximum 1,100 rpm, enough to deal with all of its assigned targets. The third, it is cheaper to acquire and maintain the 2A72 guns.

    So 330 RPM + 330 RPM = 1100 RPM? Laughing Laughing Laughing Laughing Laughing Laughing Laughing Laughing

    kopyo-21 wrote:
    You write a lot but that don't help you to create your owned phisics laws, deny the Newton's conservation of momentum laws and escape from facing with the reality.

    I repeat: Where was the momentum from the propellant gasses in your calculations? Don't try to talk about "denying Newton's conservation of momentum laws" when you blatantly ignored the momentum of 0.12 kg of propellant gasses coming out of the barrel at 1.5 times the speed of the 30mm shell. So where did it go? Did 0.12 kg disappear in to thin air? Magic? You yourself acknowledged the rocket effect of propellant gasses, so why are you ignoring it?

    kopyo-21 wrote:
    Your informations about 2A72 gun's mechanism, out of your intention, just help to make more clearly how it spread out its recoil over 2 stages, the first 260 mm and the second 65 mm. That help you nothing to prove your points and to refuse that, the longer moving back is, the less recoil force is.

    Why do you think I'm saying that recoil force isn't reduced by a long recoil stroke? Are you blind? I never said anything "to refuse that, the longer moving back is, the less recoil force is". In fact, this is what I said:

    Just because the barrel moves back by 330-335mm does not mean that it decelerates at the same rate throughout.

    I'm saying that the majority of the recoil absorption comes in the last stage with the massive shock absorber spring:



    instead of the tiny return spring:



    Why do you even try to twist my words when they are clearly recorded in text for everyone to see? Do you seriously think that people here are as retarded as you?

    Yes, it's in 2 stages, and the first stage is not nearly as strong as the second. Do you understand? You can't treat the entire 330-335mm recoil stroke as a single decelerating stage. The deceleration of the barrel is much lower during the first stage because its only being resisted by a much smaller spring. During the second stage, it's being resisted by a small spring and a very large spring.

    kopyo-21 wrote:
    Back to 2A72 gun, there are alot bullshits floating on internet about it without supportive data. Those bullshits just come from stupid netizens who just hear the rumors from some where and easily thrashed by someones.


    Are you writing an autobiography?

    kopyo-21 wrote:
    Back to data from 1990's, the firing accuray, both HEI and API rounds, of 2A72 guns on BMP-3 and on the BMP-1 (Clever turret) is the same with 2A42 gun on BMP-2 so it is stupid to use its firing accuracy factor to deny it.

    Please share this data. It's not that I don't believe you, because I also believe that the accuracy of the 2A72 is perfectly reasonable when it has a barrel support, but you talk like you have some secret information that nobody else has. Why don't you bless us with this knowledge?

    kopyo-21 wrote:
    There are some methods to improve the firing accuracy of 2A72. The first is attaching its barrel to a rigid sleeve support like BMP-3, BMP-1 "Clever", Uran-9 and Ukrainian BTR-3/4. The other is what "VPK" LLC do with BTR-82A. Instead of using the sleeve support like others, they just decrease its ROF by realizing that, the gun's barrel needs a while to recover its designed status after each firing so just simply give it enough time to recover. Finally, the 2A72 gun on BTR-82A achieves the same firing accuracy like 2A42 gun on BMP-2.

    Why are you telling me this, when you've read me telling you the same thing several times already? You really are blind, aren't you?

    Oh, and no, needing to lower the rate of fire does not make the 2A72 as accurate as the 2A42. If you need to lower your ROF to be as accurate as a cannon with a higher ROF, it means that the level of accuracy is not the same at the same rate of fire.

    kopyo-21 wrote:
    You may not know, the BTR-82A is the first and only vehicle sofar that apply the airbrush HEI round for its 2A72 gun. Therefore, although its slower down ROF, its effectiveness is still much more than others.

    So you really are blind. BTR-82A uses the TKN-4GA-01. The sighting complex with an airbursting function is the TKN-4GA-02. Get your facts straight. Same applies to everything you say, basically.

    kopyo-21 wrote:
    Besides beeing imposible to answer why most of successfull ligh combat vehicles in both Russia and Ukraine using 2A72 gun instead, you also can not answer why the Chelyabinsk Tractor Plant (GSKB-2) leaded by chief designer VL Vershinsky  and the Instrument Design Bureau (KBP) leaded by chief designer A. G. Shipunov chose 2A72 guns for their BMPT project "781" instead of 2A42 guns. They all were much knowledgeable and smart enought to chose the best for their project. The guns totally were instaled outside of the hull so this time was not because of the "smocky issue" anymore.

    First of all, 781 has a completely different hull compared to the BMPT that we see now, and it has two turrets and not one. What was considered better specifically? Were the experts thinking that 2x 30mm turrets + 2x 30mm GL allows 781 to engage 4 targets simultaneously, thus making it better than a BMPT with 1x 30mm turret + 2x 30mm GL? We know that the BMPT has only one feed link for each gun, so it cannot fire both AP or both HE. Did 781 have selectable dual-feed for its 2A72 guns? Was that the reason why they thought that it was better? Or is it only you that thinks that it is better because you have a hard-on for the 2A72 and you don't care that it was rejected in favour of the BMPT that we have now? So strange to see you jerking off over a rejected prototype like the 781 when you were talking about the BTR-90 and other vehicles with the 2A42 not being adopted. Selective reading, perhaps? The most obnoxious thing you said, however, was this:

    "Besides beeing imposible to answer why most of successfull ligh combat vehicles in both Russia and Ukraine using 2A72 gun instead"

    2A72 is simpler, lighter, more compact, cheaper, easier to maintain and can be just as accurate as a 2A42 with a barrel support. It also has an electrical cocking and re-cocking system instead of the manual cocking mechanism on the 2A42, which required 20 tugs on a lever to cock the bolt and ready the cannon to fire. There's plenty of reasons why the 2A72 is good for a light combat vehicle that needs a 30mm cannon. Unfortunately, you have gotten so mixed up that you've forgotten that you were arguing for the 2A72 to replace the 2A42 on the BMPT, which is completely inconsistent with all your other arguments. Talk about light combat vehicles all you want, but the BMPT is not a light combat vehicle. Also, you mentioned KBP. Are you not aware that the "Epoch" turret with a 2A42 was designed by KBP? They all were much knowledgeable and smart enough to choose the best for their project, agree?  Wink

    Anyway, since you like the 781 so much, I think you have to look a little more closely at those 2A72 guns. Notice that the guide rings aren't mounted to anything? Those guns do not have barrel supports. Goes to show just how much attention they paid to the design Laughing Besides, it's pretty funny to see you put so much weight behind the mere existence of the 781 when the KBP design bureau also created this variant and this variant for the Object 781 hull. So, according to your logic, the knowledgeable and smart people of KBP Tula wanted to choose the best for their project, so they chose the weapons of the BMP-3 for the weapons of their BMPT project prototype... Yeah right. Experiments are just experiments. The fact that you are making this such a big deal isn't really a surprise. You take huge logical leaps of faith pretty often, after all.


    Last edited by Interlinked on Fri Feb 02, 2018 11:05 am; edited 1 time in total

    kopyo-21

    Posts : 188
    Points : 190
    Join date : 2013-08-21
    Location : Bangkok - Thailand

    Re: BMPT programme

    Post  kopyo-21 on Fri Feb 02, 2018 11:02 am

    Ha ha ha, talking bla bla just help you fool around stupid people like you, Interlinked.

    All of what you bla bla in post by post have shown you are so stupid, not me. You know why? Because the most of stupid ones also know about the advantages of the long-recoil operated gun but you.

    Let I help you to answer about BMPT project 781. They used 2A72 guns because they had brain and not stupid like you. Is that answer satisfied you?

    I am wrong about max ROF of 2A72, is that make you fine? However that is just as dumb as you. Do you know why? Read it "Rate of fire: 350-400 rds./min".
    http://www.kbptula.ru/en/productions/small-arms-guns-grenade-launchers/guns-machine-guns/2a72

    Yeah, start bla bla that 350-400 rpm is close to 330 rpm. Let go.

    PS: Just realize, you still think that 2A42 guns on BMPT-72 can use both feeding port parallel. That why you are unabble to understand what "improve the feeding" on new BMPT means. Poor you.


    Last edited by kopyo-21 on Fri Feb 02, 2018 11:40 am; edited 2 times in total
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Fri Feb 02, 2018 11:09 am

    A temper tantrum when you are proven to be an obvious liar. How predictable Laughing

    AJ-47

    Posts : 122
    Points : 123
    Join date : 2011-10-05
    Location : USA

    Re: BMPT programme

    Post  AJ-47 on Sat Feb 03, 2018 12:14 am


    I saw a picture from the Heimimim airport Syria, when President Asad check BMPT looks to me like Terminator-1 with 5 people and 2 AGL but with Terminator-2 turret.
    Is somwbody can explain it? and how its called?
    Thanks
    avatar
    GarryB

    Posts : 18555
    Points : 19111
    Join date : 2010-03-30
    Location : New Zealand

    Re: BMPT programme

    Post  GarryB on Sat Feb 03, 2018 12:21 pm

    Garry, that's not how the 2A72 works. The barrel and bolt both recoil backwards together when a shot is fired (so the total mass of the recoiling elements is actually a bit higher than 36 kg as the weight of the barrel alone would suggest). You can't increase the rate of fire of the cannon by having bolts of different weights because the bolt is already very small and lightweight, especially compared to a 2A42 bolt, and its weight is much smaller than the recoiling barrel so increasing the weight of the bolt won't increase or decrease the momentum of the recoiling elements by much, so you won't change the rate of deceleration by much. For reference, here's a 2A72 bolt:

    You have misunderstood what I said.

    The rate of fire of the 2A72 is low because the reciprocating parts are heavy... just like using the heavy bolt on the MG-42.

    To get a higher rate of fire make the barrel fixed so the part moving back and forward is only the very light bolt... which will move very very fast.... greatly increasing rate of fire.

    I saw a picture from the Heimimim airport Syria, when President Asad check BMPT looks to me like Terminator-1 with 5 people and 2 AGL but with Terminator-2 turret.
    Is somwbody can explain it? and how its called?

    Interesting... can you post that picture here?

    Anyway... I am wondering about the new model terminators will likely be designed for unmanned turrets so there should be tons of room for dual feed mechanisms for two guns in the turret so this dual feed BS can finally be put to rest.

    It always seemed rather stupid to have single ammo feeds on dual feed guns... the whole advantage of two guns is higher rate of fire yet there are many twin and multi gun models with higher rates of fire that use single feed designs that should be rather more suitable.

    I would actually think twin 23mm guns would offer high rate of fire, max ammo capacity, yet use a standard army calibre (as used in late model Hinds).

    AJ-47

    Posts : 122
    Points : 123
    Join date : 2011-10-05
    Location : USA

    Re: BMPT programme

    Post  AJ-47 on Sat Feb 03, 2018 3:42 pm

    GarryB wrote:


    I saw a picture from the Heimimim airport Syria, when President Asad check BMPT looks to me like Terminator-1 with 5 people and 2 AGL but with Terminator-2 turret.
    Is somwbody can explain it? and how its called?

    Interesting... can you post that picture here?


    check this:

    https://www.rbth.com/defence/2017/06/30/russia-tests-terminator-2-in-syria_792975
    avatar
    Interlinked

    Posts : 160
    Points : 162
    Join date : 2017-11-07

    Re: BMPT programme

    Post  Interlinked on Sat Feb 03, 2018 4:38 pm

    GarryB wrote:
    You have misunderstood what I said.

    The rate of fire of the 2A72 is low because the reciprocating parts are heavy... just like using the heavy bolt on the MG-42.

    To get a higher rate of fire make the barrel fixed so the part moving back and forward is only the very light bolt... which will move very very fast.... greatly increasing rate of fire.

    In that case, I definitely misunderstood what you said, but the bolt of this new weapon that you are proposing would have to be completely different from the 2A72, and you'd need to have a different locking method or some way to access the propellant gas so that the bolt can be unlocked. If modifying the barrel is unacceptable, perhaps a roller-delayed blowback action like the G3 and MP5 would do, or a lever-delayed blowback action like the FAMAS, but regardless, the design of the cannon would have to be overhauled in a major way to accommodate the new locking mechanism. I'm sure it's possible, but highly impractical.

    GarryB wrote:
    I would actually think twin 23mm guns would offer high rate of fire, max ammo capacity, yet use a standard army calibre (as used in late model Hinds).

    I think you'll be interested in this:



    GSh-23V or GSh-30K plus an AG-30 grenade launcher on a turret for the BTR and BMP series or an MTLB, or anything, really.




    Sponsored content

    Re: BMPT programme

    Post  Sponsored content


      Current date/time is Tue Nov 13, 2018 12:29 am