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Thread: Airbus: European Future Fighter Program

  1. #121
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    Quote Originally Posted by Blue Apple
    The extra complexity of the M88 is a direct result of the requirements for a very compact engine. The EJ200 is considerably longer (and larger), it wouldn't have worked for an the French requirements.
    Quite how stacking 3 additional blade rows (fan IGV plus one HPC stage consisting of rotor and stator) onto those present on the EJ200 makes for a more compact engine baffles me...

    Actually, the EJ200 is simply a somewhat more powerful engine with correspondingly higher air throughput and hence larger size. In terms of length, its con-di nozzle (as opposed to the M88 ejector) contributes over and above the simple matter of scale, but pound for pound the EJ200 is the more compact of the two and the net result is a better T/W ratio.

    Quote Originally Posted by Blue Apple
    The larger the engine (and its thrust), the easier it is to reach a high TWR. It's not obvious that an EJ200 scaled down to M-88-2 size & thrust would match its TWR.
    Not according to the scaling laws I'm aware of. All else equal, thrust scales with air mass flow which scales with cross sectional area (i.e. to the second power of linear dimension), weight scales with volume (third power of linear dimension).

    Quote Originally Posted by Blue Apple
    Besides, "paper" spec mean little. Sea-level thrust isn't going to matter much at altitude or in supersonic regime.
    A con-di nozzle will though - small weight and subsonic SFC penalty, major supersonic thrust and SFC benefit. Which is why after about 1980 there have been few engines outside China other than the M88 that still use an ejector.

  2. #122
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    no. M88 sfc is lower, sorry. the convergent/divergent effect is obtained using cold CMC outlets. expansion of hot exhaust from hot flaps is further guided by cold parts. emulates con di nozzle, zimpler and far better for IR signature.

  3. #123
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    Quote Originally Posted by halloweene
    the convergent/divergent effect is obtained using cold CMC outlets.
    Other than the CMC material, just like the M53 and other engines by manufacturers the world over going right back to the 1950s, in other words.

    It works reasonably well, and may have a minor IR signature advantage, but in terms of (supersonic) performance, con-di wins - handsomely.

  4. #124
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    Quote Originally Posted by Ryan View Post
    It disciplines it by leaving it outside the EU but IMO that's a good thing.
    It's better for Turkey to be outside as it's budget and military procurement is not constrained. EU money will make Russia formidable military power in Middleast and that in turn will make it deploy even more powerful weopons in Europe
    http://russianconstruction.com/news-...s-gazprom.html

  5. #125
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    Quite how stacking 3 additional blade rows (fan IGV plus one HPC stage consisting of rotor and stator) onto those present on the EJ200 makes for a more compact engine baffles me...
    well, an engine that's half a meter shorter, obviously is more compact...

  6. #126
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    Well, in absolute terms a 75kN engine is going to be more compact than a 90kN engine - the EJ200 is more advanced, but not THAT advanced...

    I believe I made it quite clear that I was comparing on a relative basis. Scale an EJ200 down to 75kN and it's going to get significantly shorter, though the longer con-di nozzle might prevent it from actually being shorter than the M88. It will end up being lighter though.
    Last edited by Trident; 19th June 2017 at 19:11.

  7. #127
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    Other than the CMC material, just like the M53 and other engines by manufacturers the world over going right back to the 1950s, in other words.

    It works reasonably well, and may have a minor IR signature advantage, but in terms of (supersonic) performance, con-di wins - handsomely.
    The CMC mateerial stays cold, thats why it emulates con-di. like (something very different), the air intakes used compressed air to emulate a shock cone (another "simple" way)

  8. #128
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    no. M88 sfc is lower, sorry. the convergent/divergent effect is obtained using cold CMC outlets. expansion of hot exhaust from hot flaps is further guided by cold parts. emulates con di nozzle, zimpler and far better for IR signature.
    Nope, EJ200 0.74lb/lbfhr, M88 0.78lb/lbfhr. Why? EJ200 has higher pressure ratio and higher BPR both of which improve cruise efficiency.

  9. #129
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    It's better for Turkey to be outside as it's budget and military procurement is not constrained. EU money will make Russia formidable military power in Middleast and that in turn will make it deploy even more powerful weopons in Europe
    http://russianconstruction.com/news-...s-gazprom.html
    Not with oil/gas at current prices.

  10. #130
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    well, an engine that's half a meter shorter, obviously is more compact...
    And an Adour engine is even more compact, what's your point? Size is only comparable when specified against thrust.

    The CMC mateerial stays cold, thats why it emulates con-di. like (something very different), the air intakes used compressed air to emulate a shock cone (another "simple" way)
    The air intakes are pitot, hence why top speed is M1.8.

    https://web.archive.org/web/20131214...formance-data/

    Doesn't matter jack if the CMC material stays cold when there's a huge plume of hot gas flying out the back and you're moving through the air at 600mph.

    Please, please, you're embarrassing yourself. Stop pretending the engine is a whole lot cleverer than it really is. Nobody even claims that the EJ200 is ground-breaking but it is definitely, definitely better than the M88 and one of the reasons the Typhoon scored 9.0 for a/c performance in the Swiss eval and the Rafale only scored 7.0.
    Last edited by Ryan; 20th June 2017 at 09:45.

  11. #131
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    Ryan
    It's better for Turkey to be outside as it's budget and military procurement is not constrained. EU money will make Russia formidable military power in Middleast and that in turn will make it deploy even more powerful weopons in Europe
    http://russianconstruction.com/news-...s-gazprom.html
    Not with oil/gas at current prices.
    The EU is seeking to amend the Turkey-EU Customs Union to include Natural Gas and Oil. But Turkey is making this contingent on EU membership which will never happen. See https://en.trend.az/world/turkey/2766180.html

    Europe knows that Turkey will impose tariffs on oil and gas transits.

  12. #132
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    @ Ryan

    I responded to:

    Quite how stacking 3 additional blade rows (fan IGV plus one HPC stage consisting of rotor and stator) onto those present on the EJ200 makes for a more compact engine baffles me...
    so yes, it has one more row and yet IS more compact

    but then again, you'd have to understand what's written before answering in order to say something in relation to the discussion... anyway

  13. #133
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    I get the sense from some of the French contributors that Rafale is too good to need replacing within the next 20years.

    Surely if the older airframes are not worth upgrading by 2030, something else must replace them? I dont want to get into a debate over whether Rafale can cut it in 20 years time, but I am confused why there is always a lack of enthusiasm from you guys when it comes to future projects?

    I had the same reaction to questions about how FCAS was viewed in France (excepting halloweene here), but it seems there is now a grudging acceptance that FCAS might have a role to play...

  14. #134
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    so yes, it has one more row and yet IS more compact

    but then again, you'd have to understand what's written before answering in order to say something in relation to the discussion... anyway
    The pressure ratio is lower though. Obviously you can build a shorter engine if your PR is 12% lower.

  15. #135
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    I get the sense from some of the French contributors that Rafale is too good to need replacing within the next 20years.

    Surely if the older airframes are not worth upgrading by 2030, something else must replace them? I dont want to get into a debate over whether Rafale can cut it in 20 years time, but I am confused why there is always a lack of enthusiasm from you guys when it comes to future projects?

    I had the same reaction to questions about how FCAS was viewed in France (excepting halloweene here), but it seems there is now a grudging acceptance that FCAS might have a role to play...
    Just another case of more nations investing in stealth even though it's a waste of time.

    ...NOT.

  16. #136
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    @ mrmalaya

    it's rather that the french officials have planned that the rafale would be the frontline french fighter well into the 40's.. so, it's not about not willing a replacement from the posters, but rather keeping in mind that nothing new will be introduced before that timeframe.. the rafale will be modernized as much as considered necessary, but the real works on a new airframe probably won't start until something like a good 10 years from now (which would leave them some good 15 to 20 years to develop it)
    Last edited by TooCool_12f; 20th June 2017 at 11:57.

  17. #137
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    Quite how stacking 3 additional blade rows (fan IGV plus one HPC stage consisting of rotor and stator) onto those present on the EJ200 makes for a more compact engine baffles me...
    How you can miss than one engine is half a meter shorter than the other baffles me.

    Compact: "arranged within a relatively small space"

    => "pound for pound the EJ200 is the more compact of the two" makes no sense, compactness is about volume, not weight.

    Not according to the scaling laws I'm aware of. All else equal, thrust scales with air mass flow which scales with cross sectional area (i.e. to the second power of linear dimension), weight scales with volume (third power of linear dimension).
    Are you seriously suggesting that engine length scales linearly with air mass flow? Really?

    Meanwhile, in the real world, we know what a M88 scaled to EJ200 thrust looks like, SNECMA ever provided the specifications a few years ago.

    The extra 20% in thrust results in:
    - a 29% increase in cross-section
    - a 2.3% increase in length
    - a 9.8% increase in weight

    => 20% more thrust, 30% more volume, 10% more weight... no comment...

    I believe I made it quite clear that I was comparing on a relative basis. Scale an EJ200 down to 75kN and it's going to get significantly shorter, though the longer con-di nozzle might prevent it from actually being shorter than the M88. It will end up being lighter though.
    Given that the 60/90KN M88 ECO ended up (barely) lighter than the EJ200 (985kg vs 990kg) so I wouldn't be so sure...

    Please, please, you're embarrassing yourself. Stop pretending the engine is a whole lot cleverer than it really is. Nobody even claims that the EJ200 is ground-breaking but it is definitely, definitely better than the M88 and one of the reasons the Typhoon scored 9.0 for a/c performance in the Swiss eval and the Rafale only scored 7.0.
    You're the only one claiming that the EJ200 is "definitely, definitely* better". Reality is much more complex that that, a better engine on paper is not always superior, especially once put inside an airframe. The Spey Phantom is an excellent example.

    *that kind of repetition, it sounds like Trump, doesn't it?

  18. #138
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    You're the only one claiming that the EJ200 is "definitely, definitely* better". Reality is much more complex that that, a better engine on paper is not always superior, especially once put inside an airframe. The Spey Phantom is an excellent example.

    *that kind of repetition, it sounds like Trump, doesn't it?
    Stop making pathetic excuses. The reason people need to repeat themselves is because French die-hards don't listen to reason and can never admit anything of theirs is worse than anything of anybody else. Lower SFC, higher TWR.

    Don't try muddy the waters by strawmanning. The Spey gave shorter take-off and better range, it was only at higher speeds it suffered due to being wider, which required an airframe modification for fit. Now the M88 ECO, which is the only M88 close to the EJ200 is also wider than the M88-2 and EJ200, so this comparison backfires on you, especially when the Rafale has a top speed of M1.8 according to Dassault, whereas the Typhoon can do M2+ or even M2.35 by some estimates.

    Given that the 60/90KN M88 ECO ended up (barely) lighter than the EJ200 (985kg vs 990kg) so I wouldn't be so sure...
    Stop already. You might as well compare an M53 to a Junkers Juno or a Rafale to an F4 such is the time gap. The XG-40 was under testing as far back as 1986. So wow, after 30 years you have an engine that has roughly the same TWR, but is 2 inches wider and still has higher SFC. Does it even fit in an unmodified Rafale? Meanwhile the XG-40-2 with a TWR of 12:1 existed 25+ years ago. It's also not really even an M88 derivative given given the size, PR and weight differences. So way to not catch up 30 years late. What does that make the M88 ECO? The aircraft equivalent of the Gripen E?

    compactness is about volume, not weight.
    So let's look at the M88 ECO even though it isn't the same engine as the M88. 787mm diameter vs 737mm. Length 361mm vs 400mm.

    M88 ECO
    (0.787^2/4) * 3.610 = 0.560m^3

    EJ200
    (0.737^2/4) * 4.0 = 0.543 m^3

    Oh wow, EJ200 wins again. Not to mention that increasing cross-section is very unfavourable in aerodynamics.

    As regards weights. Very dubious about believing weights on an engine not in production. People spent a decade believing the Rafale was about 1,000lbs lighter than it actually was, so I'm not going to read anything into a difference of 8.5lbs (based on RR and Snecma figures).
    Last edited by Ryan; 20th June 2017 at 12:58.

  19. #139
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    The Spey gave shorter take-off and better range, it was only at higher speeds it suffered due to being wider, which required an airframe modification for fit.
    The Spey was an early turbofan and suffered a considerable drop off in thrust at high speeds and altitudes compared to the J79 which was a turbojet.

    Where are you getting the SFC from? MTU lists the SFC as .74 to .81., and as most every source lists it as the dry SFC as .81, that is the static figure. http://www.mtu.de/fileadmin/EN/7_New...ines/EJ200.pdf

    The SFC of the M88 is .78, where is this advantage you are pointing out?
    https://www.safran-aircraft-engines....t-aircraft/m88
    Last edited by FBW; 20th June 2017 at 13:08.

  20. #140
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    Not with oil/gas at current prices.
    current oil/gas prices are irrelevant for Russian military procurement as the more Russia signs contracts with China and EU. the greater the fear in Middleast of loss of revenues so they deliver much more upfront cash. Putin does not meet so many Arabs without a reason. Ruaf procurement has accelerated. This Tu-160M2 coming sooner. A-100 next year. These are the enablers that will give the capability to wipeout efficiently and effectively Middleast Airforces.

  21. #141
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    The Spey was an early turbofan and suffered a considerable drop off in thrust at high speeds and altitudes compared to the J79 which was a turbojet.

    Where are you getting the SFC from? MTU lists the SFC as .74 to .81., and as most every source lists it as the dry SFC as .81, that is the static figure. http://www.mtu.de/fileadmin/EN/7_New...ines/EJ200.pdf

    The SFC of the M88 is .78, where is this advantage you are pointing out?
    https://www.safran-aircraft-engines....t-aircraft/m88
    Possibly but the Spey itself was wider than the J79, which meant the fuselage width had to be increased, which increased drag.

    It's the lowest SFC that you take for a comparison. It's fundamentally obvious from the higher pressure ratio and higher BPR that the efficiency will be higher too, not to mention the variable inlet guide vanes on the HP comp.

    And no, almost every source does not say 0.81, most take the lower figure because that's the one relevant to optimal cruise. The 0.74-0.81 figure pertains to supercruise where the fixed geometry ramp will cause efficiency to vary.

  22. #142
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    current oil/gas prices are irrelevant for Russian military procurement as the more Russia signs contracts with China and EU. the greater the fear in Middleast of loss of revenues so they deliver much more upfront cash. Putin does not meet so many Arabs without a reason. Ruaf procurement has accelerated. This Tu-160M2 coming sooner. A-100 next year. These are the enablers that will give the capability to wipeout efficiently and effectively Middleast Airforces.
    O RLY?

    https://tradingeconomics.com/russia/gdp

  23. #143
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    It's the lowest SFC that you take for a comparison.

    nd no, almost every source does not say 0.81, most take the lower figure because that's the one relevant to optimal cruise. The 0.74-0.81 figure pertains to supercruise where the fixed geometry ramp will cause efficiency to vary
    Look, just say next time that you got the figure wrong because you took it off of wikipedia rather than rattling off a bunch of drivel. You took the lowest figure you could find for the EJ200, and then made up a narrative about "Optimal cruise", next time don't cherry pick numbers. I believe you are smart enough to know that SFC figures given for turbofans ARE static/sea level.

    If the static figures state .81 for the EJ200, and .78 for the M88, that is what is used for comparison. SFC is dynamic, it is going to be different at all altitudes (and atmospheric conditions). So exactly what altitude and speed is the "optimal cruise" for the EJ 200 according to you?

    https://books.google.com/books?id=Wz...%20SFC&f=false

    https://books.google.com/books?id=_5...%20SFC&f=false

    http://www.jet-engine.net/miltfspec.html

    Notice how the dry SFC figures for the EJ200 are all between .79 and .81?
    Last edited by FBW; 20th June 2017 at 17:30.

  24. #144
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    Quote Originally Posted by Blue Apple
    How you can miss than one engine is half a meter shorter than the other baffles me.
    How about missing that one engine delivers 20% more thrust than the other?

    I've mentioned it before and although some people seem to insist on ignoring the point, I'll do so again: I was accounting for the thrust difference when comparing sizes.

    It's pointless not to - a RB.199 is more compact than a NK-32... duh!

    Quote Originally Posted by Blue Apple
    "pound for pound the EJ200 is the more compact of the two" makes no sense
    It does, if you wish to indicate that the statement implies a correction for differences in thrust... (anybody keeping count?)

    Quote Originally Posted by Blue Apple
    Are you seriously suggesting that engine length scales linearly with air mass flow? Really?
    I hope you are not seriously suggesting that I claimed anything of the sort, because it would mean you are completely failing to understand what I was saying.

    Quote Originally Posted by Blue Apple
    Meanwhile, in the real world, we know what a M88 scaled to EJ200 thrust looks like, SNECMA ever provided the specifications a few years ago.
    We don't. ECO was NOT a straightforward scale of the original architecture!

    It introduced more modern technology than the basic M88 (among other things the larger fan was a blisk AFAIK, so a weight reduction *compared to something built to the same size based on established M88 methods*) and significantly altered the thermodynamic cycle (higher OPR). I also doubt the core (HPC) was correspondingly increased in size, as that would pretty much wipe out any commonality.

    Quote Originally Posted by Blue Apple
    Given that the 60/90KN M88 ECO ended up (barely) lighter than the EJ200 (985kg vs 990kg) so I wouldn't be so sure...
    Again, the ECO was NOT simply a basic M88 scaled to EJ200 thrust levels but a substantial tech update with major changes to the thermodynamic parameters.

    You could say it was then capable of doing (sea-level-static) what the EJ200 could do all along. Now bolt a con-di nozzle onto its back-end for comparable supersonic performance and watch what that does to its weight...
    Last edited by Trident; 20th June 2017 at 17:01.

  25. #145
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    Quote Originally Posted by Ryan View Post
    It is irrelevant comparison of statistics .as each government has own method of calculating GDP. recently Turkey made it's GDP bigger but it does not mean government has resources to implement military procurement and training with high quality people at higher rate . EU is way down the line if it starts a 5G fighter it's procurement and training in other areas will collapsed and overall military power will be approaching zero.

  26. #146
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    I get the sense from some of the French contributors that Rafale is too good to need replacing within the next 20years.

    Surely if the older airframes are not worth upgrading by 2030, something else must replace them? I dont want to get into a debate over whether Rafale can cut it in 20 years time,
    I wonder what will be left to defend in 20 years time. Might as well save the money and spend it on even more socialism. After all there are still 44% of the GDP that aren't siphoned by the leviathan.

    but I am confused why there is always a lack of enthusiasm from you guys when it comes to future projects?

    I had the same reaction to questions about how FCAS was viewed in France (excepting halloweene here), but it seems there is now a grudging acceptance that FCAS might have a role to play...
    Lack of enthusiasm for projects in cooperation which are aimed at killing the local industry? How is that surprising exactly? The fact that European countries couldn't develop a fighter or a drone alone (which is completely false as evidenced by the example of the Rafale, which turned out cheaper than the 4 partners' Typhoon) would only mean that we are broke and that we need to fix our economic & political system, not that we need to find other ways to develop weapons that always force you to cut into your independence & sovereignty, & which lowers your industry base.

    The logical step when your politicians ruin your country is NOT to attack your industrial base even more by forcing them to compromise with others, share knowledge and lose key competences, but oust the criminals & install someone who could adopt coherent economics policies instead.

    Nic

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    Just another case of more nations investing in stealth even though it's a waste of time.

    ...NOT.
    How many missions will the F35 do in first day of war scenario that a UCAV can't, and what's the extra-cost over the lifetime of the program for those extra capabilities?

    Over 90% missions will be training, which doesn't require stealth.
    Of the war missions, 99,9% will be over third world countries to install Jihad Joes & then to flatten the same Jihad Joes once they lift a finger towards israel.

    Of the 0,1% of the <10% missions where a plane that isn't stealth, how many couldn't be done by stand-off weapons &/or Stealth UCAV? Wouldn't it be cheaper to keep a fleet of those (which you are going to have anway!) for the very few instances that you need 1st day of war capability?

    Drones will replace the F35 in what it was designed for (fly over contested airspace territory to look for targets) & missiles exist for 1st day of war scenario.

    The F35 is an impressive aircraft (or is going to be at some point, maybe), but the cost benefit ratio is ridiculous.

    Nic

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    Look, just say next time that you got the figure wrong because you took it off of wikipedia rather than rattling off a bunch of drivel. You took the lowest figure you could find for the EJ200, and then made up a narrative about "Optimal cruise", next time don't cherry pick numbers. I believe you are smart enough to know that SFC figures given for turbofans ARE static/sea level.

    If the static figures state .81 for the EJ200, and .78 for the M88, that is what is used for comparison. SFC is dynamic, it is going to be different at all altitudes (and atmospheric conditions). So exactly what altitude and speed is the "optimal cruise" for the EJ 200 according to you?

    https://books.google.com/books?id=Wz...%20SFC&f=false

    https://books.google.com/books?id=_5...%20SFC&f=false

    http://www.jet-engine.net/miltfspec.html

    Notice how the dry SFC figures for the EJ200 are all between .79 and .81?
    The 0.74 is not wrong for subsonic cruise. The figure for the Rafale will be much higher than 0.78 at supersonic cruise speeds too, especially with pitot intakes and lack of proper con-di nozzle. The other reason why SFC has a range is the HP variable inlet guide vane, which will change depending on throttle setting, i.e. optimise for thrust or cruise.

    Sorry but a text book and random internet site has no weight over the manufacturer. This is just typical of the Rafale fan. Manufacturer's datasheet ignored and straight to unofficial blogs and other similar such sources. The 0.74 figure you claim is from wikipedia originated from an old Rolls-Royce page which is no longer available and clearly MTU still back up this figure.

    Except the official one from the manufacturer, which is all that counts. Also note the author of the second book has a French name.
    Last edited by Ryan; 20th June 2017 at 18:00.

  29. #149
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    Nicolas 10

    1. UCAVs are not here yet and won't be for some time.

    2. UCAVs aren't well suited to A2A.

    3. You don't build a fighter jet for the lowest threat environment.

  30. #150
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    It is irrelevant comparison of statistics .as each government has own method of calculating GDP. recently Turkey made it's GDP bigger but it does not mean government has resources to implement military procurement and training with high quality people at higher rate . EU is way down the line if it starts a 5G fighter it's procurement and training in other areas will collapsed and overall military power will be approaching zero.
    The point is that your GDP collapses and rises with the price of oil.

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