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Thread: Russia claims new tank invisible to radar/IR

  1. #451
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    Quote Originally Posted by zraver View Post
    Its not impossible. I don't know the real specs for EFC barrel life either the 120mm or 125mm. It seems off though since muzzle energy from both using the latest rounds is very similar. You need a lot of pressure to propel a sabot to useful combat speeds. Both suffer less wear or handle pressures better than older rifled barrels. A quick internet search shows claims of 1500 EFC for the US/German gun and 1200 for the Russian gun. The few hundred rounds claim seems to be based on open source information about the 120mm rifled gun used in the Arjun/Chieftan (Challenger?) posted by DRDO which states a life of 500 EFC.
    Thank you Zraver, very concise and useful!

  2. #452
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    yesterday had a nice beer chat about Armata with same like myslef proactive amature inquirer. Because the profession of that amature is aviation engineer he was concerned about energy sufficiency to feed active array radar on the object like tank with engine of just 1500 horse power, which is 1103,27 Kw. For a tank of just 48tons this engine is OVERCAPACITY, however for a powerful radar (actually 3 of them) it is just right. However an electric generator working on an engine cannot transfer all of that 1103,27 Kw into electric power, after some calculation he came to a conclusion that tank can use those radars only with engine on high usage (unless it carries heavy and big batteries), and preferably without movements or with short movements to make sure supply of enough power to its radars.

    on my argument that SAM mobile units are carried by trucks he noted that there a special power generator truck in such SAM battery to supply energy to its radars. So I was puzzled. I told him about earlier discussion somewhere about heating of the radars and he confirmed that even on an aircraft it is a problem which requires cooling systems whose wight makes up to half of the radar module total weight.

    Anyway, the introduction of some emission equipment to armored vehicles is a done deal. However, such emission equipment may change the design of AV big time due to energy and heat factors.

  3. #453
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    Quote Originally Posted by Garry View Post
    yesterday had a nice beer chat about Armata with same like myslef proactive amature inquirer. Because the profession of that amature is aviation engineer he was concerned about energy sufficiency to feed active array radar on the object like tank with engine of just 1500 horse power, which is 1103,27 Kw. For a tank of just 48tons this engine is OVERCAPACITY, however for a powerful radar (actually 3 of them) it is just right. However an electric generator working on an engine cannot transfer all of that 1103,27 Kw into electric power, after some calculation he came to a conclusion that tank can use those radars only with engine on high usage (unless it carries heavy and big batteries), and preferably without movements or with short movements to make sure supply of enough power to its radars.

    on my argument that SAM mobile units are carried by trucks he noted that there a special power generator truck in such SAM battery to supply energy to its radars. So I was puzzled. I told him about earlier discussion somewhere about heating of the radars and he confirmed that even on an aircraft it is a problem which requires cooling systems whose wight makes up to half of the radar module total weight.

    Anyway, the introduction of some emission equipment to armored vehicles is a done deal. However, such emission equipment may change the design of AV big time due to energy and heat factors.
    A coarse approximation of combined drag forces on hard level ground is that drag force is in proportion to the square of the speed. At constant speed in a straight line (no turning) on hard ground, the propulsive force called tractive effort is equal to the combined drag force.

    Drive wheel torque is directly proportional to tractive effort. Drive wheel power is proportional to the product (multiply) of drive wheel torque and vehicle speed, so to counter combined drag when traveling straight on hard level ground the power requirement rises with the cube of the speed. More power is required to climb, turn, and/or traverse soft ground.

    Likewise in coarse approximations, drag internal to the driveline is treated as being near constant in each gear range, so drive wheel power is proportional to engine power.

    1/8 of the propulsive power is needed at 1/2 speed in straight line movement on flat hard ground.
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  4. #454
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    I believe the Armata has 3 small AESA radars for hemispherical coverage with a range of about 3km for use with the Afghanit APS to target incoming RPGs, and anti-tank missiles. They may have some utility in spotting drones, helos, or low flying aircraft as well, but that isn't their primary function, and I can't imagine they draw enough power to require the full output of the engine.

    If the engine is oversized for the weight of the tank, it is surely to allow the Armata to retain mobility with the APS system active. What good is an active protection system if you have to come to a stop when you turn it on?

    AESA radars may use quite a bit of juice, but the ones installed on the Armata aren't even in the same league as actual AESA radars on SAM systems that are trying to detect aircraft at extended distances. Name:  92N6E-Deployed-Missiles.ru-1S.jpg
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  5. #455
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    Quote Originally Posted by SteveDaPirate View Post

    If the engine is oversized for the weight of the tank, it is surely to allow the Armata to retain mobility with the APS system active. What good is an active protection system if you have to come to a stop when you turn it on?
    If you slow to 79% of maximum straight line speed, you free up 50% of the propulsive power otherwise needed at maximum speed, if you have a transmission that works efficiently at reduced speeds. Some such as the HMPT-500 family developed by General Electric in Pittsfield Mass (not by L3 in Muskegon Mich) are efficient across wide range of operating speeds, but many others are not.
    Last edited by JRT; 10 Aug 17, at 18:55.
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  6. #456
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    Quote Originally Posted by SteveDaPirate View Post
    I

    If the engine is oversized for the weight of the tank, it is surely to allow the Armata to retain mobility with the APS system active. What good is an active protection system if you have to come to a stop when you turn it on?

    AESA radars may use quite a bit of juice, but the ones installed on the Armata aren't even in the same league as actual AESA radars on SAM systems that are trying to detect aircraft at extended distances. Name:  92N6E-Deployed-Missiles.ru-1S.jpg
Views: 74
Size:  636.0 KB

    None of that matters a whit when it comes to power generation though. Modern vehicles generate power via an alternator not an electrical generator. Where they do use generators such as APU's they are powered independent of the main engine. Tanks don't need oversized engines to generator electricity. IF the Armata has a big engine its for mobility reasons. Not just top speed which can only be so fast, but also for acceleration, hill climbing, mud and other uses.

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