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    PAK-DA: News

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    GunshipDemocracy

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    Re: PAK-DA: News

    Post  GunshipDemocracy on Sat Jan 12, 2019 3:34 am

    PapaDragon wrote:
    GunshipDemocracy wrote:Not sure if you noticed: codename for new bomber is  Messenger (Poslannik)...

    I ain't no Russia expert but could it be that Poslannik means Emissary?

    true, envoy can be too, in diplomacy. But the messenger to me better fits with context, it is sent when diplomacy depleted all its arguments lol1 lol1 lol1


    Also, where was that codename mentioned? I didn't see it anywhere.
    [/quote]



    the last sentence of article I've quoted . OK you read only headlines ]. No worries, we all do respekt respekt respekt
    http://militarynews.ru/story.asp?rid=1&nid=499163


    As reported, in 2009, the Tupolev Design Office signed a contract with the Ministry of Defense of the Russian Federation for research work under the code "Messenger", as a result of which a draft draft of PAK DA was prepared.
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    GarryB

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    Re: PAK-DA: News

    Post  GarryB on Sat Jan 12, 2019 9:20 am

    why? bomber shall be either really fast (Anchar?) or very steath.

    Why?

    F-22 is supposed to be stealthy and it can fly supersonically.

    Supersonic is neither and most of path flies with subsonic speeds.

    Supersonic in dry thrust is very stealthy...

    agreed T-4 made no sense from military and economical sense, but OK looked cool

    Would have been like the US Hustler... enormous fuel bill, but not actually safe when flying near large SAMs.

    If they can get 23 tons of thrust dry from the upgraded NK-31 then supercruising in the Tu-22M3M would make it rather more capable... flying at supersonic speeds of mach 1.5-1.6 in full dry thrust instead of mach 0.7-0.8 means flying twice as fast on the same throttle setting. With swept wings in low drag mode it could probably reach its normal top speed of Mach 2 with just 4 tons less thrust than in full AB with old engines.

    AB is dumping fuel directly into the exhaust so its effect on range is crippling... but flying extra fast in supercruise mode with a low thrust setting has the opposite effect on range and also the ability to intercept the aircraft... the F-35 would probably not be able to catch you, and the F-22 would need to use full AB shortening their range too.

    why AAMs only in non strategic missions? AAMs increase chance to survive and deliver actual load.

    On strategic missions most major SAM bases, radar sites, and airfields will have already been nuked and on strategic missions the new cruise missile carriers are unlikely to get within 3,000km of the target area with 5,000km and greater ranged missiles as primary weapons.

    then you likely loose stealth and some range. Your main advantage over Tu-160.

    Why do you think you would lose stealth?

    No AB, and the modest increase in IR sig is worth it to cover ground twice as fast and be rather harder to intercept.

    The minor loss of range would be compensated for with increased operational weights...

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    GunshipDemocracy

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    Re: PAK-DA: News

    Post  GunshipDemocracy on Sat Jan 12, 2019 2:17 pm

    GarryB wrote:
    why? bomber shall be either really fast (Anchar?) or very steath.

    Why? F-22 is supposed to be stealthy and it can fly supersonically.

    not even close to B-2 in terms of payload and range tho




    GB wrote:Supersonic is neither and most of path flies with subsonic speeds.Supersonic in dry thrust is very stealthy...

    so what is difference in exhaust temperature and fuel consumption?





    GB wrote:
    agreed T-4 made no sense from military and economical sense, but OK looked cool

    If they can get 23 tons of thrust dry from the upgraded NK-31 then supercruising in the Tu-22M3M would make it rather more capable...

    then you have ask yourself why nobody even considered it in Tupolev?


    .
    GB wrote:
    why AAMs only in non strategic missions? AAMs increase chance to survive and deliver actual load.
    On strategic missions most major SAM bases, radar sites, and airfields will have already been nuked and on strategic missions the new cruise missile carriers are unlikely to get within 3,000km of the target area with 5,000km and greater ranged missiles as primary weapons.

    if all is nuked no need to send bombers then and if not then you loose most of your bombers before they deliver anything... I still think DEW is better in such cases though



    GB wrote:
    then you likely loose stealth and some range. Your main advantage over Tu-160.

    Why do you think you would lose stealth?

    No AB, and the modest increase in IR sig is worth it to cover ground twice as fast and be rather harder to intercept.

    The minor loss of range would be compensated for with increased operational weights...


    yet, neither Russians nor Americans thought bout it without  reason? I dont think so.
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    GarryB

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    Re: PAK-DA: News

    Post  GarryB on Sun Jan 13, 2019 1:46 am

    not even close to B-2 in terms of payload and range tho

    No, but as a fighter it doesn't need that level of payload or range... if you scaled the F-22 to the size of the B-2 I doubt you'd get the payload AND the range, but you should be able to get one or the other...

    so what is difference in exhaust temperature and fuel consumption?

    A supercruising jet engine doesn't run hotter... it has a much higher speed airflow through the engine to allow operation at supersonic flight speeds.

    The fuel consumption would be worse but it is still dry thrust so would be less than half that of full AB, but the aircraft would be moving twice as fast.

    In basic terms if you have a car with an after burner that worked by simply increasing power by dumping fuel into the exhaust, then you trade range for speed... which is sometimes worth it and sometimes not... you can decide for yourself at the time.

    With a super cruising engine you can still have an AB, but you can achieve 80% of the top speed with dry thrust without dumping enormous amounts of fuel into the system to get a high speed.

    For a plane instead of running the engines at 80% dry thrust and flying 12,000km at 850km/h... which means flying for 14 hours... you run the engines at 100% dry thrust but you travel at 1,700km/h for say 10,000km... you are only increasing fuel consumption by 20% but you are travelling twice as fast...

    The radius of flight of the Tu-160 at top speed of mach 2 is 2,000km, so a normal flight of say 11,000km might be 10,000km at 850km/h and 1,000km at high speed to make interception harder.

    A super cruising bomber wouldn't need to fly in AB except at takeoff to get airborne with max weight... this would extend its range because in flight it does not need to use AB which wastes fuel and is a clear IR signal...

    then you have ask yourself why nobody even considered it in Tupolev?

    Maybe they did but the management decided they wanted a thicker wing profile for larger weapons so lower flight speeds are required because supercruising is not possible with such a high drag thick wing profile...

    if all is nuked no need to send bombers then and if not then you loose most of your bombers before they deliver anything... I still think DEW is better in such cases though

    Well first of all the only heavy bombers Russia has is the Tu-22M3, the Blackjack and Bear are cruise missile carriers, and the ICBMs and SLBMs are to clear the way for the cruise missiles rather than the bombers. The cruise missiles will hit cities and other population centres.

    yet, neither Russians nor Americans thought bout it without reason? I dont think so.

    I would expect the new Blackjacks will definitely supercruise... if they can increase the thrust of their engines the way they did with the Al-31 where they have pretty much gone from 12 tons thrust to just over 18 tons thrust, then with 25 tons thrust they might get to 30 tons thrust or even better.

    I suspect they have already decided that the PAK DA is to replace the Bear as the cheap subsonic bomber... except with stealth it wont be so cheap.

    Giving it a small tail surface and allowing transonic performance will make it much safer, but I suspect they want a real bomb truck for theatre bombing operations in the Backfire role...
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    Isos

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    Re: PAK-DA: News

    Post  Isos on Sun Jan 13, 2019 8:21 am

    With a super cruising engine you can still have an AB, but you can achieve 80% of the top speed with dry thrust without dumping enormous amounts of fuel into the system to get a high speed.

    Supercruise still needs lot of fuel and the range is still shorter than with subsonic cruise speeds.
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    GarryB

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    Re: PAK-DA: News

    Post  GarryB on Sun Jan 13, 2019 9:33 am

    Yeah, but the point is that supercruising does not shorten flight range in practical terms.

    A plane like a MiG-31 can fly 720km to a target and back to base at 19km altitude and mach 2.35, but if it flys subsonically at a more efficient cruising speed of mach 0.8 then it has a radius of 1,450km to a target and back to base.

    Installing new engines with a dry thrust of 15 tons is hard to calculate, because fuel consumption will be higher because fuel burn is calculated as kgs of thrust per hour, but dry thrust is much less than AB thrust so the fuel efficiency will be less than halved but the speed at which the aircraft moves is doubled.

    The point is that the engine on the current MiG-31 in dry thrust burn 0.72 kgs of fuel per kilogramme of thrust per hour, but its max dry thrust setting is 9.5 tons of thrust.

    A new much more powerful engine for supercruising probably has the same or better fuel efficiency, but because it is generating more thrust it will of course burn more fuel, but because the aircraft is moving faster it might not lose that much performance in terms of actual range and it will certainly get to its destination much faster.

    The full AB thrust of the engine is 1.9kgs/kg hour... so it is more than doubled.

    At high altitude the MiG-31 can actually maintain supersonic speed without AB, but I am told it needs AB to accelerate past the speed of sound so technically it does not super cruise...

    The point is that for most aircraft trying to intercept a target moving at Mach 1.6 or so will need to use AB itself for the speed to catch the target... which dramatically shortens the interception range of aircraft and missiles trying to stop it.

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