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    Su-57 Stealth Fighter: News #5

    LMFS
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    Post  LMFS on Mon Mar 11, 2019 3:00 pm

    Austin wrote:Yes from Technology pov its  not a great achievement , both are similar to 117 Engine in terms of what they achieved , IIRC F119 has a worst T:W ratio some where around 8:1 this is from my memory , 117 has 10.5:1
    TWR in F119 is penalized by the very heavy 2D TVC nozzle, F119-derived F135's TWR is apparently around 11,5.
    Dry thrust of F119 is estimated above 11 tonnes, compare to 8.8 in most modern AL-41F1... it is a massive difference for two very similarly sized engines and the evidence a non-VCE cannot be an efficient supercruising engine and economical in subsonic regime at the same time.
    Besides, temperature tolerance on F135 sets the bar by now by a wide margin and reliability looks very good too. Those are truly outstanding engines to my understanding. If US would dare putting them on 4G fighters we would see some serious discussions about the convenience of buying 5G in the planned numbers IMO...[/quote]
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    Post  GunshipDemocracy on Mon Mar 11, 2019 8:27 pm

    Austin wrote:
    Yes from Technology pov its  not a great achievement ,

    And what would be such achievement?
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    Post  LMFS on Mon Mar 11, 2019 8:59 pm

    GunshipDemocracy wrote:And what would be such achievement?
    I guess he means variable cycle engine would be the real deal Cool
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    Post  magnumcromagnon on Mon Mar 11, 2019 9:58 pm

    LMFS wrote:
    GunshipDemocracy wrote:And what would be such achievement?
    I guess he means variable cycle engine would be the real deal Cool

    Does he mean a supersonic jet engine with comparable dry thrust to a subsonic jet engine of similar size?
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    Post  GunshipDemocracy on Mon Mar 11, 2019 11:24 pm

    LMFS wrote:
    GunshipDemocracy wrote:And what would be such achievement?
    I guess he means variable cycle engine would be the real deal Cool

    oh then we need revolution with each new engine design unlike in nature where evolutionary approach dominates.
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    Post  LMFS on Mon Mar 11, 2019 11:54 pm

    magnumcromagnon wrote:Does he mean a supersonic jet engine with comparable dry thrust to a subsonic jet engine of similar size?
    What do you mean exactly with supersonic and subsonic jet engine?

    Just in case it helps: an engine optimized for supersonic flight would be a turbojet or a turbofan with very low bypass ratio. It would naturally have, with the same rough size as a turbofan of bigger BPR, more dry thrust. But it would not be very economic for subsonic flight. Hence the idea of the VCE, opening and closing ducts around the hot part of the engine to modify the BPR. This would be revolutionary (previous attempts F120 and original AL-41 were abandoned) and would really set the Su-57 apart... at least until US comes up with something similar or, apparently, better, since they work on three stream technology.

    oh then we need revolution with each new engine design unlike in nature where evolutionary approach dominates.
    An engine either is VCE or is not, there are no gradual stages between fixed and variable BPR
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    Post  GunshipDemocracy on Tue Mar 12, 2019 1:15 am

    LMFS wrote:
    oh then we need revolution with each new engine design unlike in nature where evolutionary approach dominates.
    An engine either is VCE or is not, there are no gradual stages between fixed and variable BPR

    that was my point , Sir. That would be revolution. BTW so how many  existing fighters do have VCE?
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    Post  LMFS on Tue Mar 12, 2019 2:40 am

    GunshipDemocracy wrote:that was my point , Sir. That would be revolution. BTW so how many  existing fighters do have VCE?
    Apart from (maybe) the Su-57? NONE! Laughing
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    Post  Austin on Tue Mar 12, 2019 5:29 am

    LMFS wrote:
    Austin wrote:Yes from Technology pov its  not a great achievement , both are similar to 117 Engine in terms of what they achieved , IIRC F119 has a worst T:W ratio some where around 8:1 this is from my memory , 117 has 10.5:1
    TWR in F119 is penalized by the very heavy 2D TVC nozzle, F119-derived F135's TWR is apparently around 11,5.
    Dry thrust of F119 is estimated above 11 tonnes, compare to 8.8 in most modern AL-41F1... it is a massive difference for two very similarly sized engines and the evidence a non-VCE cannot be an efficient supercruising engine and economical in subsonic regime at the same time.
    Besides, temperature tolerance on F135 sets the bar by now by a wide margin and reliability looks very good too. Those are truly outstanding engines to my understanding. If US would dare putting them on 4G fighters we would see some serious discussions about the convenience of buying 5G in the planned numbers IMO...
    [/quote]

    It was not the nozzle 119 Engine was developed in 80's and had T:W Ratio not exceeding 8:1 , It did had higher dry and AB thrust.

    Like Mig-31 Engine has higher thrust but TW ratio of 5:1.

    Atleast VCE technology is the next revolution in engine so having VCE in izd 30 is important because there is no other engine under work we know of for miltary fighters.

    As for other aspect like size thrust etc , We will have to compare 117 Data with Izd 30 to make the right conclusion on this , Since we dont have it we cant say one is exponontially better than the other

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    Post  GunshipDemocracy on Tue Mar 12, 2019 9:45 am

    LMFS wrote:
    GunshipDemocracy wrote:that was my point , Sir. That would be revolution. BTW so how many  existing fighters do have VCE?
    Apart from (maybe) the Su-57? NONE! Laughing

    Thank you , Sir. Then it makes Su-57 5++ relly. Or F-22/F-35 are 4++ (33+35 =57 BTW)
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    Post  LMFS on Tue Mar 12, 2019 12:42 pm

    Austin wrote:It was not the nozzle 119 Engine was developed in 80's and had T:W Ratio not exceeding 8:1 , It did had higher dry and AB thrust.
    F119 is the same size class of F110, but it is (supposedly, since there are still no official weight data for it) much heavier than it or a comparable AL-31, despite having less stages. P&W claims a high TWR for the engine. F135 is a direct development (not a new generation engine but rather an enlarged version using the same core technologies and with higher BPR) and is comparably much lighter. All indicates it is the nozzle but I have found no hard data

    Atleast VCE technology is the next revolution in engine so having VCE in izd 30 is important because there is no other engine under work we know of for miltary fighters.
    It would be the best option for the future, I agree.

    As for other aspect like size thrust etc , We will have to compare 117 Data with Izd 30 to make the right conclusion on this   , Since we dont have it we cant say one is exponontially better than the other
    We are making assumptions, legit I think, based on what has been said by Russian sources (Izd. 30 is the real 5G+ engine that will make the plane shine in regards of supercruise, stealth and agility). I wonder if we will get any hard data in the next decade, you see the situation with F119 data almost 15 years after commissioning...


    GunshipDemocracy wrote:Thank you , Sir. Then it makes Su-57 5++ relly. Or F-22/F-35 are 4++ (33+35 =57 BTW)
    Indeed. A VCE is planned for the F-35 but, unlike the US fighter, the Su-57 aero has been designed for efficient supersonic flight from the start. So it will reap bigger benefit from the improved propulsion. A plane like F-35 is not really optimized for supercruising, so even increasing dry thrust will be comparably not that effective since much of it will be needed to overcome inherently high wave drag. That means, it may supercruise, but probably slower and less efficiently than SU-57. And the A/B mode of a VCE is improving thrust less than in a turbofan of high BPR, so this newer layout per se will not necessarily produce very big improvements in acceleration and manoeuvrability for the plane. It will be rather the overall technological improvement over the development time that may help with max thrust. Improving cooling  may be an advantage of the type of engine foreseen in the F-35 though.

    EDIT: Did you take a look at the original interview? Do you think the statement indicates clearly that Izd. 30 is indeed VCE??
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    Post  LMFS on Thu Mar 14, 2019 11:28 am

    Su-57: an innovative solution TsAGI

    In early 2010, the air first flew the prototype aircraft T-50. Russian multi-role fighter of the fifth generation, developed by OKB imeni P. O. Sukhoi within the framework of the project "PAK FA" (Promising aviation complex tactical aviation), now is called su-57.

    In the Central Aerohydrodynamic Institute named after Professor N. E. Zhukovsky new aircraft started to be developed in the framework of scientific research in 1999. Professionals leading center of aviation science in cooperation with the Sukhoi design Bureau was to create a fighter with a number of unique features that have properties, the implementation of which are mutually contradictory. It was necessary to develop aircraft system with functions of fighter, interceptor and attack aircraft. The high combat effectiveness of the PAK FA should be provided with technical solutions in the field of aerodynamic layout, stability and controllability, control systems, propulsion, radar and infrared visibility, avionics and weapons.

    Together with employees of the Sukhoi design Bureau and TSAGI scientists have developed the aerodynamic shape of the aircraft that meets the requirements of the fifth generation fighter. Were created not having analogues in the world adjustable stealth intake, which ensures steady operation of the engine on all flight modes. The specialists of the Institute developed a control system for maneuvering the aircraft is statically unstable in the lateral and longitudinal control channels. Ensuring the strength of the airframe with the widespread use of new and composite materials is another challenge that scientists TSAGI has successfully solved. The result was requirements met to the weighted design parameters of the aviation system, the weight of perfection of the aircraft. In a short time carried out work in the areas of safety from flutter, aeroelasticity, design and shimmy of the wheels.

    Specialists of the Institute conducted a unique research design the layout of a fighter. In wind tunnels of TSAGI were investigated 28 different models of aircraft; the total number of trials exceeded 32 thousand. Successfully completed testing of new materials and design elements.

    After the first flight of the prototype studies for improvement of flight of the machine continued. So, over the next nine years in TSAGI refined the aerodynamic characteristics of the complex were compared with the results of flight tests, worked out the safety of the new aircraft armament. In the process of preparing and conducting flight tests were carried out frequency of tests all created for this aircraft.

    http://www.tsagi.ru/pressroom/news/4264/
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    Post  Isos on Thu Mar 14, 2019 12:01 pm

    Were created not having analogues in the world adjustable stealth intake,

    I'm sure they use that to reach very short landing distances by closing the intakes inside the airplane so that they become parachutes and slow down the aircraft.

    Like the system on mig-29 that closes the intakes to prevent something going inside but it wasn't inside the intakes but at the entrence so it didn't help slowing down the aircraft.

    But having something like that inside the intakes transforms them into parachutes.
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    Post  LMFS on Thu Mar 14, 2019 12:44 pm

    But that would choke the engines, that is not something you want to do during the landing...
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    Post  LMFS on Thu Mar 14, 2019 5:38 pm

    Terrific link by Jo Asakura:

    http://www.up-pro.ru/library/innovations/management/okb-sukhoi.html

    Among many interesting topics, clarification of the short landing capabilities of the Su-57:

    With the help of SIC becomes possible shortened to 300 m, landing at high angles of attack.


    As previously proposed, Su-57 can land pretty much like birds do, increasing AoA to reduce speed until stall and still managing to land instead of crashing, automatically  Cool
    Su-57 Stealth Fighter: News #5 - Page 21 Su-57_10

    This changes completely approach to carrier landing. Amazing plane.
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    Post  william.boutros on Thu Mar 14, 2019 7:02 pm

    LMFS wrote:Terrific link by Jo Asakura:

    http://www.up-pro.ru/library/innovations/management/okb-sukhoi.html

    Among many interesting topics, clarification of the short landing capabilities of the Su-57:

    With the help of SIC becomes possible shortened to 300 m, landing at high angles of attack.


    As previously proposed, Su-57 can land pretty much like birds do, increasing AoA to reduce speed until stall and still managing to land instead of crashing, automatically  Cool
    Su-57 Stealth Fighter: News #5 - Page 21 Su-57_10

    This changes completely approach to carrier landing. Amazing plane.

    This looks crazy even more so for carriers.
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    Post  LMFS on Thu Mar 14, 2019 7:46 pm

    william.boutros wrote:This looks crazy even more so for carriers.
    I would think that too, if it was a proposal and not a statement of an existing capability Razz

    In regards of carriers, this type of approach would actually be pretty appropriate for the non flaring landing needed, only it would end with the airplane touching the deck softly and at very reduced speed, instead of literally crashing in a more or less controlled way (take a look at the sink rates naval fighters have to handle) as it is done currently...
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    Post  Vladimir79 on Thu Mar 14, 2019 9:24 pm

    LMFS wrote:Terrific link by Jo Asakura:

    http://www.up-pro.ru/library/innovations/management/okb-sukhoi.html

    Among many interesting topics, clarification of the short landing capabilities of the Su-57:

    With the help of SIC becomes possible shortened to 300 m, landing at high angles of attack.


    As previously proposed, Su-57 can land pretty much like birds do, increasing AoA to reduce speed until stall and still managing to land instead of crashing, automatically  Cool
    Su-57 Stealth Fighter: News #5 - Page 21 Su-57_10

    This changes completely approach to carrier landing. Amazing plane.

    It is all good in theory but there are too many variables for a pilot or computer to make that a reliable method of landing.
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    Post  kvs on Thu Mar 14, 2019 10:15 pm

    LMFS wrote:Terrific link by Jo Asakura:

    http://www.up-pro.ru/library/innovations/management/okb-sukhoi.html

    Among many interesting topics, clarification of the short landing capabilities of the Su-57:

    With the help of SIC becomes possible shortened to 300 m, landing at high angles of attack.


    As previously proposed, Su-57 can land pretty much like birds do, increasing AoA to reduce speed until stall and still managing to land instead of crashing, automatically  Cool


    This changes completely approach to carrier landing. Amazing plane.

    This ignores the real world of boundary layer eddies and shear layers. Recall the clown pilot of the SSJ-100 demonstrator who crashed into a ridge at
    the base of an Indonesian volcano because he though he was the cat's meow of piloting skills. He clearly never heard of orographic buoyancy waves
    (mountain waves) and ignored ATC instructions to keep a higher altitude, so people died. Large vertical displacements are possible in the planetary
    boundary layer under all sorts of weather conditions. Having a descent geometry that aggravates the chance of slamming the ground is just asking for it.


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    Post  LMFS on Thu Mar 14, 2019 10:48 pm

    Vladimir79 wrote:It is all good in theory but there are too many variables for a pilot or computer to make that a reliable method of landing.  
    Hey, I am not making this up. This is a pretty serious review of Sukhoi technological achievements...

    kvs wrote:This ignores the real world of boundary layer eddies and shear layers. Recall the clown pilot of the SSJ-100 demonstrator who crashed into a ridge at
    the base of an Indonesian volcano because he though he was the cat's meow of piloting skills. He clearly never heard of orographic buoyancy waves
    (mountain waves) and ignored ATC instructions to keep a higher altitude, so people died. Large vertical displacements are possible in the planetary
    boundary layer under all sorts of weather conditions. Having a descent geometry that aggravates the chance of slamming the ground is just asking for it.
    I guess birds do not know this, since they land like that literally always. I am perfectly aware that the flexibility with which the aero geometry of a bird can be adapted is way bigger than that of a modern plane, but it is obvious that progress is made and more control surfaces + digital FCS allows for feats that were before not possible. I concede the wake of a carrier can be a extreme condition to perform such a landing, but, landing conditions aside, Sukhoi has essentially confirmed recently the same landing distance that this article from 2014 was already advancing.

    PAK-FA patent states explicitly the aim of the design to bring low-speed controllability to an unprecedented level. LEVCONS allow to keep flow attached to the lifting body at higher AoAs than it would be otherwise possible. TWR of the plane is expected to be above 1 for all but full load (how fast the engines can throttle is of course an important issue and I don't have hard info there I admit). Besides 3D TVC is available so I think there are ways the plane can fight a sudden loss of lift... within a given set of weather conditions of course!

    I would ask you in response:
    > Do you think this is lie, incorrect reporting or simply me misunderstanding the source?
    > How would you explain the Su-57 being capable of landing in half the distance of Su-35, other than by using an increased AoA approach to get a very low min speed?
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    Post  Isos on Thu Mar 14, 2019 11:02 pm

    LMFS wrote:But that would choke the engines, that is not something you want to do during the landing...

    Turn them off when touch down.
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    Post  LMFS on Thu Mar 14, 2019 11:23 pm

    Isos wrote:
    LMFS wrote:But that would choke the engines, that is not something you want to do during the landing...
    Turn them off when touch down.
    How do you power the plane then? Apart from that, in a carrier this approach would be impossible to start with, since engines must be in full throttle position during the catch, lest the arresting fails and the aircraft needs to take off again!
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    Post  GarryB on Fri Mar 15, 2019 2:36 am

    The amount of air you could block by changing the air intake is minimal and would have no practical effect on landing... certainly nothing at all like an actual parachute, which the Su-57 actually carries.

    The variable intake means it can open wider and let more air in during takeoff to let the engine develop more thrust, while when flying at supersonic speeds it constricts down to reduce the amount of air flowing in to the engine so it doesn't choke on too much air.

    Most high speed fighters like the MiG-29 and Su-27 have variable intakes and can get up to flight speeds of mach 2.3 or 2.4.

    The F-18 and F-16 have fixed air intakes that are simpler and lighter but limit their flight speeds to mach 1.8 and 2.0 respectively.

    Regarding this landing concept taken from the way birds land, that is rather interesting... the thing they did with the Yak-41 was develop a fully computer controlled landing system that western experts described as having the aircraft under rock solid control for landing and take off.

    The Yak-41 was such a dangerous aircraft it needed this automated landing system and an auto ejection system taken from the one on the Yak-38 (and improved of course) so that during landing or takeoff if there was a problem... a roll or yaw or engine failure the crew were immediately ejected... expensive in planes but good for aircrew.

    The area around an aircraft carrier can be very controlled and current laser systems used at airports to detect aircurrents and wind shears should make an automatic landing system for carriers rather efficient and effective...

    Certainly worth exploring...
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    Post  Austin on Fri Mar 15, 2019 5:22 am

    https://tvzvezda.ru/news/opk/content/201811131419-5mml.htm

    Surpasses all analogues: the developer revealed the features of the engine Su-57

    the General Designer-Director “OKB im. A.M. Cradles "Yevgeny Marchukov.

    “I would say that this generation 5+ is slightly ahead of the fifth one. It is to this generation that the engine corresponds to specific gravity, specific consumption and specific gravity, ”Marchukov said. Marchukov noted that the engine surpasses all foreign analogues in terms of specific gravity, is a completely new product and has nothing to do with the engine of the Su-35 fighter.
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    Post  Austin on Fri Mar 15, 2019 5:23 am

    what does specific gravity means , I think its the translation error

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