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Rafale 2018 Thread: Europe's best Eurocanard

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  • FBW
    replied
    No comment on the two false statements you made? Sorry, peddle BS somewhere else. Thanks.

    here learn how modern FCS work:
    https://www.flightglobal.com/news/ar...rafale-334383/

    http://www.codeonemagazine.com/f35_a...ml?item_id=187
    Last edited by FBW; 21st February 2019, 18:46.

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  • ThincanKiller
    replied
    Originally posted by TomcatViP View Post
    The HUD G indicator in the Rafale is capped at 10G. Why then?

    Also you should know, the structure of the fuselage had to be redesigned to meet weights targets and expected operational life. But true, the wing is rock solid thanks to its structure inherited from a 1970 design
    It is not caped, it will unfold when you reach 10G,
    airframe is not limited to the wing and if you refer to Rafale it is not a "redesign" but a structural strengthening in specific areas for the Naval version (landing gear and hook), the basic airframe is the same, as I was saying.



    If you watch early Rafale videos, you will see a slightly different HUD symbology, mainly that preceding the high AoA test flight, of which we have not much documentation to submit, still they managed to record AoA passed 100* and negative speed of 40kt.
    Originally posted by FBW View Post
    Oh boy. Ill open a separate thread to answer this. The above is convoluted nonsense.

    Why don't you complain to L-M about the data they provided to the press then?

    https://www.flightglobal.com/news/ar...impact-381683/

    Yes you better, nonsense for you seems to be everything you do not know about basic A-C design, not mentioning how to compute a turn rate.

    I rest my case.

    Originally posted by FBW View Post
    just to point out the easiest....


    Only one F-35 variant was to be 9G rated, ever. That was the F-35A. And the FCS in the F-35A allows 9.5G (NzW dependent) without over- G log You can look it up. Anything else you want to make up?
    wait- let me get you straight, your saying the FCS protects an F-16 from ever exceeding 9G correct? Wow.



    But by memory, E-F Typhoon was designed with an Ultimate Structural Load of 1.2, vs an international standard of 1.5; compare to demonstated Rafale 1.85 and you go the drift, there is NO substitute for structural strength and if you ignore it this is what happens, airframe fatigue is no joke.

    https://youtu.be/U22_7jsQy7s
    Last edited by ThincanKiller; 21st February 2019, 18:42.

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  • TomcatViP
    replied
    which prove my point, the A-C is designed to pull those 11.0G and the pilots does so,
    The HUD G indicator in the Rafale is capped at 10G. Why then?

    Also you should know, the structure of the fuselage had to be redesigned to meet weights targets and expected operational life. But true, the wing is rock solid thanks to its structure inherited from a 1970 design

    Leave a comment:


  • FBW
    replied
    Oh boy. Ill open a separate thread to answer this. The above is convoluted nonsense.
    just to point out the easiest....


    Only one F-35 variant was to be 9G rated, ever. That was the F-35A. And the FCS in the F-35A allows 9.5G (NzW dependent) without over- G log You can look it up. Anything else you want to make up?

    wait- let me get you straight, your saying the FCS protects an F-16 from ever exceeding 9G correct? Wow.
    Last edited by FBW; 21st February 2019, 18:08.

    Leave a comment:


  • ThincanKiller
    replied
    Originally posted by FBW View Post

    No idea what you are trying to say here. G onset can be gradual or quick depending on maneuver. A hard pitch up is rapid G onset, a bank to 90* turn is rapid G onset. And yes, maneuvers with rapid G onset can lead to over G even with modern DFCS.



    According to your comments quote: "
    every single G demand FCS allows momentary over-G." momentary over-G
    implies G onset or a completely bugged FCS, on itself G onset is not over-G, furthermore, any decent FCS will prevent that to happen.





    Originally posted by FBW View Post
    Your mistaking override with margins allowable within the FCS control law. As an aircraft approaches the limits, the pilot will receive the auditory warning, and in some cases the stick will push back to attempt to unload. That does not mean that the DFCS will not allow the pilot to exceed the 9G limit, but it will be logged and depending on load, possibly damage the aircraft.


    No I am not, clearly, you also imply that manufacturers which designed airframes with NO Structural Load margin did the opposite, FCS are designed to prevent excessive airframe fatigue and over-stress, not to allow for extra-G.





    Originally posted by FBW View Post
    Most every 9G aircraft have varying margins usually 50% and higher between design load factor and ultimate load factor. None are going to "pop rivets" exceeding the 9G FCS limiter by a small margin.


    Clarify what "most " implies please. I can guaranty you that such over-ride doesn't exist on several 9.0G A-C such as F-16 or E-F Typhoon, on one because of a hard FCS limit, the second for the reasons I stated, therefore no way those 9.0G icons will ever let you pull more than 9.0G.





    Originally posted by FBW View Post
    Can you name one aircraft that meets this criteria you speak of?
    Sure thing:

    E-F Typhoon, ALL F-35, 2 of which originally required to meet a 9.0. Limit, then limited for meeting weight targets, look at their politico-industrial history, those design choices (or redesign) are very much documented, and, in the case of Typhoon, this was debated in some British Professional forum after a near miss by a demo Typhoon, after the intervention of an ex-demo RAF Typhoon pilot called Tarnished, things were a little bit clearer for everyone, you seems to have missed this topic.

    Typhoon first failed its Structural Load Limit tests and needed some spar redesign, later on, in Operation, pilots experienced airframe over-stress pulling slightly more than 9.0 g using an over-ride knob situated on the stick, since then, the E-F FCS cannot be overriden and the A-C will never let you go over 9.0G.

    In the case of F-16 it is not the number of G which this overriding capability will affect but the number of G you can pull regardless of the configuration, I never eared of a F-16 pulling more than 9.0G, sorry.


    Originally posted by FBW View Post
    That is a flawed argument. We are talking contemporary 9G rated fighters with modern FCS. With some previous generation of fighters, F-15C for example, lacking a modern DFCS there were specific airspeeds and weights which it could pull 9G (very limited) approaching the g limit would result in "bitching betty" warnings to back off the stick. Yet an F-15C pulled upwards of 12-14G (nearly twice the 7.5 allowable G within most of the flight envelope) in a pull up to avoid ground collision.


    There is nothing flawed in this argument, and I do not mix A-Cs with modern FCS and those of the previous generation where only an audio warning will tell you what is going on, the number of G pulled accidentally by a F-15 is not only irrelevant but also not comparable.





    Originally posted by FBW View Post
    With the newer generation of fighters, that 9G envelope is much larger but still limited by weight, eternal loads, asymmetric loads. Specifically in pitch and roll, FCS will limit allowable G in certain regimes. More specifically the FCS limits the actual force on the aircraft (weight, G, acceleration) within the allowable margins.


    Wrong: Both turning performances and number of G are computed with Structural limits inputs, which you quote by mentioning external loads btw, Structural limit defines how much G your airframe CAN or CANNOT take, then aerodynamics and physics.

    The combination of those gives you an instantaneous turn rate, add thrust for sustained turn rate, all of which results in a given number of G, but the Structural limit dictates it first thing.

    Again, if you design an A-C with lower Ultimate Structural Load limits to gain some performances, as was the case for Eurofighter, or fail to meet your weight target as in the case of 2 out of 3 F-35 variants (one of them was not required to pull 9.0G), you always will have to limit the A-C in G, there is no way around that, and this is exactly what happened.

    The Rivet popping episodes were mentioned by Typhoon pilots in the very forum where this guy Tarnished explained all of this very clearly, more to the point, depending on energy levels, he pointed out rightly that there was little difference between 9.0G and 11.0G in most of those situation, simply because your turning radius (consider a resource as a vertical turn) will not be altered enough to avoid collision with an obstacle, otherwise said, this "override to avoid a crash" is just a complete forum legend, for your information, the overriding capability was only there before the introduction of the Ground Proximity Warning System (GPWS).


    Originally posted by FBW View Post
    The Rafale is limited to 5.5g with external fuel or heavy weapons (as with many aircraft), the FCS constantly adjusts the limits within the NzW, as the aircraft gets lighter or loses external stores, the available G increases. The Rafale's DFCS allowing the pilot to exceed the design load factor of 9+G briefly during an airshow, while an impressive display, does not translate to 11+G loaded for combat. It's no surprise that the Rafale is ruggedly built; it is a relatively small aircraft that can carry a heavy load of fuel and weapons, it has to be structurally strong as they probably wanted to keep the structural differences between the Rafale C & M to a minimum.
    This limit is not that of the airframe but pylons, pylon anchor points and load, the airframe itself is stressed at 1.85, not those which are standards, plus you extend the debate toward points which are completely irrelevant, the airframe in itself is designed with a much higher Ultimate Structural Load limit than the international standard, and it will easily take 11.0G where other A-C are firmly limited to 9.0G for exactly the same reason, designed structural limits.

    The fact that some other A-C can accidentally go over that doesn't mean their airframe is designed for that and in many instances, pilots came back with bent airframes which in some cases meant that the A-C had to go through such intensive repairs, that preventing such occurrence fast became the only viable solution, RAF and I believe other E-F Typhoon users came to this very conclusion, this A-C is firmly limited to 9.0G, and this is now part of the baseline.

    And again you write Quote: "allowing the pilot to exceed the design load factor of 9+G briefly during an airshow" Nope.

    The "designed load factor" you mention depends on the Ultimate Structural Load factor and has got nothing to do with airshow but operational requirements, how strong your airframe is designed, if this limit doesn't allow you to go over 7.0 or 9.0G, your FCS will most likely not let you do it, especially if your Structural Load margin is lower than standard or nil, pilots pulls as many Gs as their A-Cs allows them and for Rafale it's 11.0G.

    Designed Ultimate Structural Load limit of Rafale is HIGHER (is that a word you have some difficulties with) and its airframe is designed to be as safe at 11.0G as other A-C at 9.0G and with a small margin on top, as simple as that, so you can be certain that if a pilot needs to pull 11.0G on a Rafale with the right configuration (2 X wing tip pylons AAMs in place of the smokewinder, that's a fully OP configuration), the FCS will let him do so, which is obviously not the case of many of its competitors.





    Originally posted by FBW View Post
    It's no surprise that the Rafale is ruggedly built; it is a relatively small aircraft that can carry a heavy load of fuel and weapons, it has to be structurally strong as they probably wanted to keep the structural differences between the Rafale C & M to a minimum



    That's the only time in my opinion where you get any close to reality, but shows that you do not know Rafale very well; Rafale was structurally designed from the M model requirements, even anti-corrosion coating is common, from day one they wanted an airframe stronger than the international standard to make sure it would meet 7.000 h in Navy service with high number of traps as required.

    I'm not sure its size matters that much but they certainly did manage to build a strong airframe and btw, there is no override needed to pull 11.0G, which prove my point, the A-C is designed to pull those 11.0G and the pilots does so, what's so funny about it?

    After all it is AoA limited in a way F-18 and F-35 are not, nobody is trying to tell us that this is because the US pilots needs to avoid terrain and use an override to do so.



    Last edited by ThincanKiller; 21st February 2019, 17:58.

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  • FBW
    replied
    Originally posted by halloweene View Post
    There is nothing to disagree on. A nice presentation video as all shallbe.
    It is a very nice display. Not knocking that for sure. Also find it disingenuous that you bemoan when your post leads to a shooting gallery. Didn't see a need to drag an aircraft not to be named into the discussion, but you did. Don't really see the reasoning behind constantly throwing darts at another allied nation's aircraft.

    Leave a comment:


  • FBW
    replied
    Originally posted by ThincanKiller View Post

    Hi.

    I think there are some points which we can disagree on.

    1) G onset in not structural overload.
    No idea what you are trying to say here. G onset can be gradual or quick depending on maneuver. A hard pitch up is rapid G onset, a bank to 90* turn is rapid G onset. And yes, maneuvers with rapid G onset can lead to over G even with modern DFCS.

    2) Not any 9G.0 rated fighter can over-ride the FCS, some well known Rafale competitor could, but the over-ride capability was deleted for structural limits reasons.
    Your mistaking override with margins allowable within the FCS control law. As an aircraft approaches the limits, the pilot will receive the auditory warning, and in some cases the stick will push back to attempt to unload. That does not mean that the DFCS will not allow the pilot to exceed the 9G limit, but it will be logged and depending on load, possibly damage the aircraft.

    3) The whole thing will depend on structural design: If your ultimate structural load margin is too low, (for the purpose of performance gain for example), then you're going to have to impose strict FCS limits or will start to pop rivets at 9.5G, bend spars at 10.5G, and because your airframe structural integrity was gone from the rivet popping stage, break whatever part will give way next above that.
    Most every 9G aircraft have varying margins usually 50% and higher between design load factor and ultimate load factor. None are going to "pop rivets" exceeding the 9G FCS limiter by a small margin.

    To allow for a safe G over-ride you will need a designed ultimate structural limit with enough margin to safely pull more than your standard 9.0G unfortunately, at design stage, not all 9.0G label fighters were built with such margin, even the opposite for the purpose of performance gain through TWR, some other A-C were limited below 9.0G later in their design stage in order to meet weight targets but in any case, it is debatable as to whether pulling 1 or 2 G more would save most situation.
    Can you name one aircraft that meets this criteria you speak of?

    Since you mention the difference in display style, the first thing to have a look at in order to understand why a pilot does pull high G or not lies in the airframe design, not really in anything else since it will always come into play, even with external loads, when it comes to G limits.
    That is a flawed argument. We are talking contemporary 9G rated fighters with modern FCS. With some previous generation of fighters, F-15C for example, lacking a modern DFCS there were specific airspeeds and weights which it could pull 9G (very limited) approaching the g limit would result in "bitching betty" warnings to back off the stick. Yet an F-15C pulled upwards of 12-14G (nearly twice the 7.5 allowable G within most of the flight envelope) in a pull up to avoid ground collision.

    With the newer generation of fighters, that 9G envelope is much larger but still limited by weight, eternal loads, asymmetric loads. Specifically in pitch and roll, FCS will limit allowable G in certain regimes. More specifically the FCS limits the actual force on the aircraft (weight, G, acceleration) within the allowable margins.

    As for Dassault A-Cs, since the Mirage 2000, they have the (justified) reputation to be built like bricks (to the detriment of absolute TWR-related performances) and Rafale pushed the limits with a beefy 1.85 ultimate structural load design demonstrated by ground testing, which is way above the international standard and certainly above most of its competitors.

    Since the purpose of the Rafale demo team is to demonstrate the A-C capabilities, including max instantaneous and sustained turn performances, the pilots routinely pull what the A-C is designed for, 11.0G max.
    The Rafale is limited to 5.5g with external fuel or heavy weapons (as with many aircraft), the FCS constantly adjusts the limits within the NzW, as the aircraft gets lighter or loses external stores, the available G increases. The Rafale's DFCS allowing the pilot to exceed the design load factor of 9+G briefly during an airshow, while an impressive display, does not translate to 11+G loaded for combat. It's no surprise that the Rafale is ruggedly built; it is a relatively small aircraft that can carry a heavy load of fuel and weapons, it has to be structurally strong as they probably wanted to keep the structural differences between the Rafale C & M to a minimum.

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  • halloweene
    replied
    There is nothing to disagree on. A nice presentation video as all shallbe.

    Leave a comment:


  • ThincanKiller
    replied
    Originally posted by Scooter View Post

    I did say large volumes of internal fuel was and is a big benefit. Yet, never said "no matter what". I was simply referring to the benefits of Stealth combined with the advantages of large internal fuel and weapons. Which, is a by product of.....
    One aspect of the advantages of increased fuel fraction on Rafale is rarely mentioned, compared to the Mirage 2000 which performances were foremost biased toward high altitude/high Mach numbers optimisation, the Rafale flight envelop was foreseen as preliminarily transonic/mid supersonic, and the increase in size of the bulge (Karman) at the wing-fuselage junction lower transonic drag, so you can tell that its fuel fraction is not only higher but that the design also lowers drag in the region of its flight envelop where it will operate the most.

    It is also a compromise, (like every A-C design) and with a moderate wing sweep angle compared to some other A-Cs, its Critical Mach number can be seen to be lower, but in reality, overall drag in this flight regime is also lowered by this feature, so all in all it will experience compressibility slightly earlier but its effects will also be lower, while carrying more fuel than an A-C which doesn't have this design feature (not mentioning any VLO design here).




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  • ThincanKiller
    replied
    Originally posted by FBW View Post
    halloweene
    what is this obsession with Rafale flight demonstration G?

    every single G demand FCS allows momentary over-G. Any 9G rated aircraft can pull in excess of 9G for brief periods. No manufacturer wants to have to explain why a pilot augered into the side of Mt. Blanc with collision avoidance warnings blaring because the FCS only allowed a 9G pull up when 10 would have saved the pilot (hyperbole). There is play in these FCS control laws in certain maneuvers.

    The only thing this this shows is something most of us have noticed in European flight demonstrations for some time..... they are allowed a lot more leeway and fun than the US demo teams that are highly scripted and dont allow any 9G maneuvers as part of normal demos. Does not change the fact that ALL aircraft with modern FCS are governed by weight, external loads, asymmetric loads in regard to G, pitch, and roll rates.
    Hi.

    I think there are some points which we can disagree on.

    1) G onset in not structural overload.

    2) Not any 9G.0 rated fighter can over-ride the FCS, some well known Rafale competitor could, but the over-ride capability was deleted for structural limits reasons.

    3) The whole thing will depend on structural design: If your ultimate structural load margin is too low, (for the purpose of performance gain for example), then you're going to have to impose strict FCS limits or will start to pop rivets at 9.5G, bend spars at 10.5G, and because your airframe structural integrity was gone from the rivet popping stage, break whatever part will give way next above that.

    To allow for a safe G over-ride you will need a designed ultimate structural limit with enough margin to safely pull more than your standard 9.0G unfortunately, at design stage, not all 9.0G label fighters were built with such margin, even the opposite for the purpose of performance gain through TWR, some other A-C were limited below 9.0G later in their design stage in order to meet weight targets but in any case, it is debatable as to whether pulling 1 or 2 G more would save most situation (of the kind you described of course).

    Since you mention the difference in display style, the first thing to have a look at in order to understand why a pilot does pull high G or not lies in the airframe design, not really in anything else since it will always come into play, even with external loads, when it comes to G limits.

    As for Dassault A-Cs, since the Mirage 2000, they have the (justified) reputation to be built like bricks (to the detriment of absolute TWR-related performances) and Rafale pushed the limits with a beefy 1.85 ultimate structural load design demonstrated by ground testing, which is way above the international standard and certainly above most of its competitors.

    Since the purpose of the Rafale demo team is to demonstrate the A-C capabilities, including max instantaneous and sustained turn performances, the pilots routinely pull what the A-C is designed for, 11.0G max.

    Last edited by ThincanKiller; 21st February 2019, 15:00.

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  • TomcatViP
    replied
    French Rafales conduct first Meteor firings

    French Air Force (FAF) and navy Rafale combat aircraft conducted the first test firings of the Meteor beyond-visual-range air-to-air missile on 13 February, the Direction Gnrale de l'Armement (DGA), the French defence procurement agency, announced on its website on 15 February.

    The first firing was conducted in daylight and the second at night.
    Source:
    Janes.com

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  • stealthflanker
    replied
    So, how large is "large" ?

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  • Guest's Avatar
    Guest replied
    Originally posted by OPIT View Post

    You did it, twice, by pretending that a large fuel volume is a huge benefit, no matter what. Now stop kidding or quit trolling. Your choice.
    I did say large volumes of internal fuel was and is a big benefit. Yet, never said "no matter what". I was simply referring to the benefits of Stealth combined with the advantages of large internal fuel and weapons. Which, is a by product of.....

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  • eagle1
    replied


    Quatar

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  • halloweene
    replied
    francogerman next generation fighter topic was closed?

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  • OPIT
    replied
    Originally posted by Scooter View Post

    Who said it was???
    You did it, twice, by pretending that a large fuel volume is a huge benefit, no matter what. Now stop kidding or quit trolling. Your choice.

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  • Guest's Avatar
    Guest replied
    Originally posted by BlackArcher View Post

    Most of which are not going to be in service in the 2020s for sure. And some of which will only start appearing in service in the 2030s or 2040s.
    Point is current and future fighters now in development. Will all incorporate large internal fuel loads.

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  • Guest's Avatar
    Guest replied
    Originally posted by OPIT View Post

    Funny, you still can't get it right. That's a mandatory by-product of stealth designs, not a primary goal for everyday uses.
    Who said it was???

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  • BlackArcher
    replied
    Originally posted by Scooter View Post

    Funny, most of the current and future 5th and 6th Generation Fighters will include large internal fuel volumes.....(TFX, KFX, Tempest, NGF, PCA, NGAD, etc.)
    Most of which are not going to be in service in the 2020s for sure. And some of which will only start appearing in service in the 2030s or 2040s.

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  • St. John
    replied
    I think we may have veered a little off-topic here. In fact this belongs in the historic aviation section.

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