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Thread: SAAB Gripen and Gripen NG thread #4

  1. #91
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    Quote Originally Posted by FBW View Post
    Great Question! For one, the Gripen Demo and the so-called Gripen NG are not the same. The production Gripen E/F (already is) will be heavier than envisioned and there may very well be more changes as the pre-production models move through development. The more powerful F414 is offset by that added weight and if there is a performance weakness apparent in the Gripen, that it does not have the T/W ratio of it's bigger European brothers to begin with. It is still on the lightweight side of the fighter spectrum with all of the benefits and drawbacks inherent in designing a small multirole fighter.
    I am not arguing about that.. It's possible and even probable that some weight shall be added and that the performance could be shifted accordingly. But how is that different from any other prototype on this planet? Frankly, I am not even sure if increasing the T/W was a goal of the NG, rather than greater range, more ordnance and more growth potential (read increased power to support AESA).. There is a retrofit program for the PS-05/A Mk4 radar for Gripen C/Ds but none so far for the Vixen AESA, maybe the C/D is not able to adhere to increased cooling requirements.. (?)

    http://saab.com/globalassets/publica...r_brochure.pdf
    Last edited by MSphere; 2nd February 2016 at 12:31.

  2. #92
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    From what is known so far

    Gripen C/D
    - Newbuild airframe with sub systems and components salvaged from Gripen A.

    Gripen E/F
    - Can be a conversion of current C/D airframes with new components and sub systems. Sweden decided later to have all new airframes to preserve current C/D numbers for later sale or lease.

  3. #93
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    Quote Originally Posted by alexz View Post
    From what is known so far

    Gripen C/D
    - Newbuild airframe with sub systems and components salvaged from Gripen A.

    Gripen E/F
    - Can be a conversion of current C/D airframes with new components and sub systems. Sweden decided later to have all new airframes to preserve current C/D numbers for later sale or lease.
    No. The Gripen E airframe would have been new build in any case (it's longer, larger, thicker). Sweden was thinking of reusing some minor parts of the old C/D, like canopy, ejection seat, etc.

  4. #94
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    Quote Originally Posted by MSphere View Post
    The Gripen Demo NG is an NG.. We can spend hours arguing about whether it's a true "prototype" or just a heavily reworked Gripen B under a private initiative financed by the industry but the fact is that it is an NG. It has a new airframe with additional fuel capacity, two rows of fuselage pylons, new landing gear, F414-GE engine, new satcom equipment, electro-optical RWR and MAWS by Avitronics, as well as the Vixen 1000E AESA radar. Whatever changes have been proposed for the final config prototype from your link, they will hardly be discernible..
    Actually the radar is not a vixen 1000 its an evolution of it called raven =) http://www.gripenblogs.com/Lists/Posts/Post.aspx?ID=9

  5. #95
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    Quote Originally Posted by hopsalot View Post
    http://saab.com/globalassets/commerc...g-brochure.pdf

    Gripen NG

    Empty weight, 8,000kg. Thrust, 98KN. Internal fuel, 3,400kg.

    F-35A

    Empty weight, 13,200kg. Thrust, 191KN. Internal fuel, 8,390kg.
    Yeah they'll be flying alot when empty .....F-35 is 22ton with fuel only. Gripen is 12ton with full fuel.

    Ill give you the max loaded version of it MTOW comparison.
    Weight dry wet
    31800 125 191


    92,7% 115,5% 94,9%


    16500 58 98

    You see here (surprisingly) that @ max weight the f-35 only has a 2,4% stronger engine then gripen NG (compared to weight) yet still having -35% less lift area to use, AND having much bigger air resistance

  6. #96
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    Quote Originally Posted by FBW View Post
    The more powerful F414 is offset by that added weight and if there is a performance weakness apparent in the Gripen, that it does not have the T/W ratio of it's bigger European brothers to begin with. It is still on the lightweight side of the fighter spectrum with all of the benefits and drawbacks inherent in designing a small multirole fighter.
    Yes, and one of the main benefits of the Gripen is being able to afford more flight hours for training and being able to field more planes with better availability for the same amount of financial and human resources. So T/W is hardly relevant apart from a systemic evaluation of the results of choice of craft type in the total war scenarios.

    And BTW, even with added weight (remains to be seen) it still does supercruise, which can make it reach targets faster with more fuel to hover where it needs to be.

  7. #97
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    Quote Originally Posted by Urban View Post
    Yeah they'll be flying alot when empty .....F-35 is 22ton with fuel only. Gripen is 12ton with full fuel.

    Ill give you the max loaded version of it MTOW comparison.
    Weight dry wet
    31800 125 191


    92,7% 115,5% 94,9%


    16500 58 98

    You see here (surprisingly) that @ max weight the f-35 only has a 2,4% stronger engine then gripen NG (compared to weight) yet still having -35% less lift area to use, AND having much bigger air resistance
    What possible utility is a max weight comparison? Nobody is worried about flight performance if they are flying an aircraft anywhere near its maximum take off weight.

    Besides, the F-35 has a vastly greater load carrying capacity than a Gripen NG. This is an advantage not a weakness.

  8. #98
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    Quote Originally Posted by lfd View Post
    Yes, and one of the main benefits of the Gripen is being able to afford more flight hours for training and being able to field more planes with better availability for the same amount of financial and human resources. So T/W is hardly relevant apart from a systemic evaluation of the results of choice of craft type in the total war scenarios.

    And BTW, even with added weight (remains to be seen) it still does supercruise, which can make it reach targets faster with more fuel to hover where it needs to be.
    Thrust to weight isn't relevant for a fighter anymore?

    Also, the claimed supercruise for the Gripen NG is extremely limited.

    The engine, a General Electric F414G turbofan, is a modular, fuel-efficient low-bypass ratio, afterburning turbofan with the latest technology. With a thrust rating of more than 22,000lb (98kN), the F414G produces 20% more thrust than Gripen’s current Volvo Aero RM12 power plant, and will enable super-cruise performance of Mach 1.1 with air-to-air weapons.
    Supercruise at M1.1 isn't tactically useful... it isn't really even supercruise as that is squarely in the trans-sonic region.

    A Gripen might be able to maintain a hair above M1 in level flight without turning while at its ideal SC altitude after accelerating with afterburners... but in the real world that just isn't useful. Certainly it isn't a case where the Gripen NG will be getting anywhere appreciably faster while saving fuel.

    http://saab.com/air/gripen-fighter-s...n/the-fighter/

  9. #99
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    Quote Originally Posted by lfd View Post
    Yes, and one of the main benefits of the Gripen is being able to afford more flight hours for training and being able to field more planes with better availability for the same amount of financial and human resources. So T/W is hardly relevant apart from a systemic evaluation of the results of choice of craft type in the total war scenarios.

    And BTW, even with added weight (remains to be seen) it still does supercruise, which can make it reach targets faster with more fuel to hover where it needs to be.
    "Supercruise"..... yes, the most abused new claim in fighter marketing. The Gripen Demo was able to fly above the speed of sound without afterburners. The final (production representative) E/F development airframe 39-10 has yet to fly, then Saab can assess how long, with what loads, the Gripen E/F can "super cruise". P.S. what is the IAS difference between an aircraft cruising at mach .9 and mach 1.1 at 30,000 feet?

    Edit- I don't mean the last part to be a "test", you don't have to answer. Just look it up and you'll see what I'm driving at.
    Last edited by FBW; 3rd February 2016 at 00:39.

  10. #100
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    @ Hopsalot "What possible utility is a max weight comparison?" Well, more utility then an empty comparison which you always like to give out. A good calculation would be 50% fuel and 3 air to air, where Gripen lands on 10,6ton and F-35 at 17900 with 3 aim-120. At this weight f-35s engine is luckily 25% stronger but still has 35% less wing area for lift and turn and still has at least 2-3 times the air-resistance (weapons included) so it most likely need it, to compensate lift/drag with the engine and very much so in anything above speed of sound and while lift of and landings.

    "Supercruise at M1.1 isn't tactically useful" well that is...not right at all. Low super-cruise is much more usable then high speed super-cruise since the fuel requirements at high super-cruise is terrible, a few minutes of super cruise is what you get at super-cruises @ high supersonic (f-22) 10 minutes at 1,8 then fuel is gone. Super-cruise has been done by Gripen demo at mach 1,25 and at that speed it would be able to travel for quite some time (35-55min on internal depending on load). Maybe to travel back for reload without turning on the afterburner (ir protection) or going for a faster assault. Super-cruise at mach 1.1 is in fact useful in many ways and one of them is to fire missiles above the sound barrier saving up to 50% range.

    Supersonic travel is expensive. It's expensive because the parasitic drag increases exponentially. Building and aircraft any bigger then Gripen will require one more engine to super-cruise. And having one more engine increase air resistance with bigger air intakes bigger fuel tanks and bigger body which all increase air resistance. It all increases fuel draw which result in a non useful high super-cruise. That said ! Except for a faster travel, super-cruise in low region speeds still has the above mentioned advantages.

    Last but not least, i would like to you guys to wait a few more months and you will have Gripen E flying.

  11. #101
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    here's what SC 1.1 appear as when flying subsonic
    https://www.youtube.com/watch?v=b4EASQJ0vJk
    the missile will require about five times the G capability of the target to complete a successful intercept.
    -Robert L Shaw

  12. #102
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    Quote Originally Posted by Urban View Post
    @ Hopsalot "What possible utility is a max weight comparison?" Well, more utility then an empty comparison which you always like to give out. A good calculation would be 50% fuel and 3 air to air, where Gripen lands on 10,6ton and F-35 at 17900 with 3 aim-120. At this weight f-35s engine is luckily 25% stronger but still has 35% less wing area for lift and turn and still has at least 2-3 times the air-resistance (weapons included) so it most likely need it, to compensate lift/drag with the engine and very much so in anything above speed of sound and while lift of and landings.
    Any comparison at an equivalent fuel percentage favors the F-35 because the F-35 has a much higher fuel fraction. (That was the point of my inclusion of the fuel capacities)

    Put another way... an F-35 at 50% fuel can go a lot farther and stay a lot longer. A Gripen at 50% (internal) fuel had better already be on its way home.

    The fact that even in that scenario the F-35 has a huge advantage in thrust to weight should tell you something. Also, you are wrong about their relative drag. Certainly the F-35 is a larger and draggier aircraft... but it also has almost twice the thrust and is carrying its load internally. There is no reason to think this is an area of advantage for the Gripen NG.


    "Supercruise at M1.1 isn't tactically useful" well that is...not right at all. Low super-cruise is much more usable then high speed super-cruise since the fuel requirements at high super-cruise is terrible, a few minutes of super cruise is what you get at super-cruises @ high supersonic (f-22) 10 minutes at 1,8 then fuel is gone. Super-cruise has been done by Gripen demo at mach 1,25 and at that speed it would be able to travel for quite some time (35-55min on internal depending on load). Maybe to travel back for reload without turning on the afterburner (ir protection) or going for a faster assault. Super-cruise at mach 1.1 is in fact useful in many ways and one of them is to fire missiles above the sound barrier saving up to 50% range.
    You are wrong again. Flying at M1.1 means you are transonic... high transonic maybe, but you aren't even fast enough to take advantage of "efficient" supersonic flight. Second, an aircraft that can barely SC at all (best speed of M1.1) means that it can really only do it while straight and level at its ideal altitude, at full (non-augmented) throttle. This isn't a major enabler of anything in combat.


    Last but not least, i would like to you guys to wait a few more months and you will have Gripen E flying.
    The fundamentals of the design aren't going to change. I am sure Saab's excellent marketers will make the most of it, but given that Gripen NG is merely a heavy update of a Gripen, we know what to expect.

  13. #103
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    sigh.

    These comparisons of F-35 and Gripen are rather useless, IMHO.

    They are, aircraft of two completely different classes, different designs, and also of different cost segments.


    In addition, "versus" discussions tend to be not very fruitful.

  14. #104
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    No fear fact is here. So far i have seen no figures for f135 fuel consumption. 2 Fuel consumption consists of 3 values Xg/kN·s the first value (weight) is the one that gets better if you improve engine fuel consumption. The second value is the power of the engine. The third value is for counting time.

    Say that f135 draws 25g*190kn=4750g(4,75kg/s)/sec*60=285kg per minute. Now checkout if i change that value to gripens engine power 25g*98=2450g(2,45kg)/sec*60=147kg per minute.

    Now to the interesting part. Lets assume LM outdid them selves hard when creating f135 and cut the fuel burn by 20% which is a lot, actually almost out of question. 20g*190=3800g(3,8kg)/sec*60=228kg per minute.

    With an 20% lowered fuelburn you still have 65% more fuel consumption.

    Taking known values for the (Volvo rm12) Gripen c's values, these are the theoretical values 3400kg/72kg/min=47,2 minuter=1180km full dry. WOW ! almost super cruise for the max range of the f-35 (i know, just teoretical without load)

    Conclusion A large and strong engine does not automatically get saved by good fuel consumption. And if f-35 use max throttle in dry thrust, it does not super cruise.(remember even if f-35 has exceptionally strong dry trust it can't super cruise).

    The range of f-35 is 1200km. And there will be no fast travels in supersonic or with to much load. The point im proving here is that f-35 needs it's large tanks filled to get anywhere at all and whatever you think or wish for can't change that its pure fact and anyone with a calculator can see that.

    Knowing gripen demo did mach 1.25 with dry thrust (takes alot) gets me to think flying gripens with 75% trust will be enough with full load and for quite some time over an hour easy on internals.


    hopsalot said "Certainly the F-35 is a larger and draggier aircraft... but it also has almost twice the thrust and is carrying its load internally." ??? yes and with thrust comes fuel consumption (remember full dry thrust gets f-35 max to subsonic roof not further.... and to 1.6mach with full burner)

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    Will there ever be a Sea Gripen?

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    Quote Originally Posted by tankdriver67 View Post
    Will there ever be a Sea Gripen?
    Nao (in Brazilian).
    Sum ergo cogito

  17. #107
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    latest news from brazil suggest they will do it
    the missile will require about five times the G capability of the target to complete a successful intercept.
    -Robert L Shaw

  18. #108
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    Quote Originally Posted by tankdriver67 View Post
    Will there ever be a Sea Gripen?
    Almost certainly not. It's only chance it's the Brasilian Navy, who is not swimming in money and has enough funding priorities without having to sponsor the development of a Saab "Kraken".

  19. #109
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    Quote Originally Posted by obligatory View Post
    latest news from brazil suggest they will do it
    As far as I remember, SAAB set up an office in the UK which produced a preliminary design. I guess Brazil could afford to refine the design but I don't think the government will be able to fund development, testing and production for some time.
    Sum ergo cogito

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    "Will there ever be a Sea Gripen?"
    Atm Thailand Brazil and India is interested, but it is likely to much money involved (my thoughts).

  21. #111
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    Quote Originally Posted by Urban View Post
    "Will there ever be a Sea Gripen?"
    Atm Thailand Brazil and India is interested, but it is likely to much money involved (my thoughts).
    I think the Thai carrier is designed for STOVL aircraft, unfortunately. India is currently committed to the naval Tejas (in development) so not much chance for a Sea Gripen order... but you never know what will actually happen with India. Brazil's carrier could use a Sea Gripen.
    Sum ergo cogito

  22. #112
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    Quote Originally Posted by Urban View Post
    No fear fact is here. So far i have seen no figures for f135 fuel consumption. 2 Fuel consumption consists of 3 values Xg/kN·s the first value (weight) is the one that gets better if you improve engine fuel consumption. The second value is the power of the engine. The third value is for counting time.

    Say that f135 draws 25g*190kn=4750g(4,75kg/s)/sec*60=285kg per minute. Now checkout if i change that value to gripens engine power 25g*98=2450g(2,45kg)/sec*60=147kg per minute.

    Now to the interesting part. Lets assume LM outdid them selves hard when creating f135 and cut the fuel burn by 20% which is a lot, actually almost out of question. 20g*190=3800g(3,8kg)/sec*60=228kg per minute.

    With an 20% lowered fuelburn you still have 65% more fuel consumption.
    You start by saying "fact is here" then proceed to make up a bunch of numbers?

    Yes, the F135 is a larger engine with almost twice the thrust of the F414. The F-35 also has substantially more than twice the Gripen's fuel capacity... without knowing the specifics of either aircraft's fuel consumption under cruise conditions all we can say is that the F-35 has a substantial advantage here.

    Taking known values for the (Volvo rm12) Gripen c's values, these are the theoretical values 3400kg/72kg/min=47,2 minuter=1180km full dry. WOW ! almost super cruise for the max range of the f-35 (i know, just teoretical without load)
    You have a source for a Gripen NG's fuel consumption while "supercruising" at M1.1?

    Conclusion A large and strong engine does not automatically get saved by good fuel consumption. And if f-35 use max throttle in dry thrust, it does not super cruise.(remember even if f-35 has exceptionally strong dry trust it can't super cruise).
    Conclusion, garbage in, garbage out. BTW, the F-35 does reportedly supercruise:

    The F-35, while not technically a "supercruising" aircraft, can maintain Mach 1.2 for a dash of 150 miles without using fuel-gulping afterburners.

    "Mach 1.2 is a good speed for you, according to the pilots," O’Bryan said.

    The high speed also allows the F-35 to impart more energy to a weapon such as a bomb or missile, meaning the aircraft will be able to "throw" such munitions farther than they could go on their own energy alone.
    https://web.archive.org/web/20130112...12fighter.aspx

    The range of f-35 is 1200km. And there will be no fast travels in supersonic or with to much load. The point im proving here is that f-35 needs it's large tanks filled to get anywhere at all and whatever you think or wish for can't change that its pure fact and anyone with a calculator can see that.
    1200km? Given that the F-35's combat radius is ~600nm that is a little hard to believe...

    Knowing gripen demo did mach 1.25 with dry thrust (takes alot) gets me to think flying gripens with 75% trust will be enough with full load and for quite some time over an hour easy on internals.
    Gripen Demo didn't weight 8,000kg empty, and hitting M1.25 while totally clean isn't really that impressive when you consider that the only thing a Gripen will be doing clean is an air show or running home.


    hopsalot said "Certainly the F-35 is a larger and draggier aircraft... but it also has almost twice the thrust and is carrying its load internally." ??? yes and with thrust comes fuel consumption (remember full dry thrust gets f-35 max to subsonic roof not further.... and to 1.6mach with full burner)
    Again, even accounting for increased fuel consumption the F-35 has much more fuel than a Gripen NG. You also don't know what the F-35's max sustained speed on dry thrust is but according to the above, it is at least M1.2.

  23. #113
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    Quote Originally Posted by Spitfire9 View Post
    I think the Thai carrier is designed for STOVL aircraft, unfortunately. India is currently committed to the naval Tejas (in development) so not much chance for a Sea Gripen order... but you never know what will actually happen with India. Brazil's carrier could use a Sea Gripen.
    It doesn't have a hope in India either, which has a range of available choices - N-Tejas - light, MiG-29K/Rafale-M - medium, F-35B - heavy. No space for a Sea Gripen.

  24. #114
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    Moving towards a PW-229 evolution probably better suited a bigger Gripen than F414, even in an EPE version. Too little, too late IMHO.
    Go Huskers!

  25. #115
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    Quote Originally Posted by Spitfire9 View Post
    As far as I remember, SAAB set up an office in the UK which produced a preliminary design. I guess Brazil could afford to refine the design but I don't think the government will be able to fund development, testing and production for some time.
    no, not for some time, but there would not be any rational plan behind refurbishing the carrier and all the support a/c
    without an actual fighter, and what other fighter fit better on sao paulo ?
    in fact does any other fighter fit ?
    the missile will require about five times the G capability of the target to complete a successful intercept.
    -Robert L Shaw

  26. #116
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    LCA-N should fit.
    Go Huskers!

  27. #117
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    Quote Originally Posted by Urban View Post
    "Will there ever be a Sea Gripen?"
    Atm Thailand Brazil and India is interested, but it is likely to much money involved (my thoughts).
    Chakri Naruebet is the smallest STOVL carrier ever built. I doubt it'd be possible to operate any CTOL jet fighter from her.
    Juris praecepta sunt haec: honeste vivere, alterum non laedere, suum cuique tribuere.
    Justinian

  28. #118
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    Quote Originally Posted by obligatory View Post
    no, not for some time, but there would not be any rational plan behind refurbishing the carrier and all the support a/c
    without an actual fighter, and what other fighter fit better on sao paulo ?
    in fact does any other fighter fit ?
    Let's see what happens with the French Super Etendards...
    Brief and powerless is Man's life; on him and all his race the slow sure doom falls pitiless and dark.

  29. #119
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    i'm thinking brazilians are aiming to complete the carrier for duty 2030-35,
    when Etendards are eligible for elderly home with ICU for each bed
    the missile will require about five times the G capability of the target to complete a successful intercept.
    -Robert L Shaw

  30. #120
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    Aren't the SEM too worn out?

    Nic

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