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Rafale Wins MMRCA Bid

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  • Originally posted by Defcon5 View Post
    Hitesh,

    There is a cost for Kaveri Engine, it will not be cheap, blame Secma and ToT pricing for that
    The AESA is mostly the Indianized Elta 2050. Again the same costing issue.
    unfortunately I am not myself a aero engg, though there is a much talked about issue. There is a reason why Gripen gives better engine performance with the same GE engine than the LCA. There simply not enough air going into the engine.
    A better MiG-21 is not what IAF is looking for, they are looking much beyond that.
    I have been lurking this forum for eons
    With the acquisition of Rafale, Super MKIs, upgraded M2000s, and planned induction of PAK-FAs, IAF does not need the LCA to be more than a better Mig-21. It just need a cost effective option for patrolling its skies, CAP, air-to-ground interdiction, air saturation, etc.

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    • Originally posted by Blademaster View Post
      With the acquisition of Rafale, Super MKIs, upgraded M2000s, and planned induction of PAK-FAs, IAF does not need the LCA to be more than a better Mig-21. It just need a cost effective option for patrolling its skies, CAP, air-to-ground interdiction, air saturation, etc.
      That maybe your opinion, that maybe even ADA's opinion, but that certainly isnt the IAF's opinion, I am bit in the know of the ground situation, you may ask for the blogger tarmak007 for a better explanation into the details of this. IAF is putting tremendous pressure on DRDO and GoI, to not force enormous amount of LCA's on them, NLCA project maybe cancelled altogether. The only way to solve the airflow issue, is either have an extremely powerful engine in current dimensions or to correct the intakes. But correcting the intake would require major re design work and will push the project back 3-5 years. LCA has unfortunately turned into a fat guppy rather than a fighter.

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      • Looks like India's decision may influence Brazil's choice...
        India shows data to Brazil?

        India agreed during Amorim's trip to share with Brazil some of its experiences of carrying out the open tender evaluation to select the best aircraft.

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        • The LCA is a pure delta fighter, similar in shape to the F-106. Aerodynamically, the delta has these attributes:

          - Low drag if area rule is followed; good acceleration
          - Excellent instantaneous turn rate
          - Poor sustained turn rate

          A Delta wing is able to deliver one excellent, but energy-depleting "bat turn", and then tends to go downhill. They have always had trouble working a vertical fight, almost regardless of thrust to weight. So it may be much more complicated than simple poor airflow.

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          • What is area rule., in layman's terms? What is the difference between sustained turn rate and instantaneous turn rate, in layman's terms?

            How did M-2000 and Gripen overcome the problem of energy-depleting "bat turn" and vertical fight?

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            • Originally posted by Blademaster View Post
              How did M-2000 and Gripen overcome the problem of energy-depleting "bat turn" and vertical fight?
              The Grippen uses "canards", extra surfaces in front of the wings:
              Grippen

              The Mirage has smaller, fixed, canards, but it was designed originally as an interceptor, so high speed and rate of climb were more important. The newer Rafale has bigger, all moving, canards:
              Rafale

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              • Does anyone know how many Rafales French own? Wiki says 59. If that's trye, India will have 4 times more?
                No such thing as a good tax - Churchill

                To make mistakes is human. To blame someone else for your mistake, is strategic.

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                • Originally posted by Doktor View Post
                  Does anyone know how many Rafales French own? Wiki says 59. If that's trye, India will have 4 times more?
                  I believe France has close to 200 ordered, with less than half the order delivered.

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                  • Originally posted by Blademaster View Post
                    What is area rule., in layman's terms? What is the difference between sustained turn rate and instantaneous turn rate, in layman's terms?
                    Area rule says that the cross-section of an aircraft most have a smooth, continuous increase and decrease in cross-sectional area so that there are no sudden changes in the cross-sectional area of the airframe. This is the reason for the so-called "coke bottle" effect: in order to compensate for the increase in the airframe's cross-sectional area caused by the wing, the fuselage is correspondingly "pinched", or reduced in cross-sectional area. On a graph, the cross-sectional area measurement of the airframe would be an ogival shape presenting the least resistance to airflow.

                    Chogy or Jimmy could probably give you a better definition of instantaneous turn-rate vs. sustained turn-rate but, put simply (in deference to you, Kent), instantaneous turn-rate is the aircraft's ability (or lack thereof) to change it's vector quickly, and the sustained turn-rate is an aircraft's ability (or lack thereof) to maintain a contant turn-rate without losing airspeed. Normally, an aircraft will be able to do one or the other pretty well, but not both. My understanding is the A-4 had an excellent instantaneous turn-rate, but couldn't sustain it (small wing), whereas the F-15's instantaneous turn-rate wasn't so hot (big, heavy aircraft), but it had an excellent sustained turn-rate due to it's low wing-loading and high thrust-to-weight ratio.

                    Hopefully, Chogy or Jimmy can elaborate on this, since they have first-hand knowledge of both.
                    "There is never enough time to do or say all the things that we would wish. The thing is to try to do as much as you can in the time that you have. Remember Scrooge, time is short, and suddenly, you're not there any more." -Ghost of Christmas Present, Scrooge

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                    • Originally posted by Chogy View Post
                      The LCA is a pure delta fighter, similar in shape to the F-106. Aerodynamically, the delta has these attributes:
                      It is a compound delta actually. The sweepback angle at the front wing root is lower than the angle for the rest of the wing. Exactly the opposite of the cranked arrow design of the Saab Draken.

                      The naval version has movable LEVCONS.

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                      • Originally posted by jlvfr View Post
                        The Mirage has smaller, fixed, canards, but it was designed originally as an interceptor, so high speed and rate of climb were more important. The newer Rafale has bigger, all moving, canards:
                        Rafale
                        The small "canards" on the Mirage 2000 are called strakes. They are mounted along the air intakes. They are supposed to improve slow speed and high AoA handling. As you can see from this very old video of a slow speed IAF M2000 pass alongside a piston engined trainer http://www.youtube.com/watch?feature...Y5LxN_18#t=61s , they seem to work well. Though I am not an aeronautics guy, so I could be mistaken about the strakes playing an important part there, in which case, apologies.
                        Last edited by Firestorm; 15 Feb 12,, 20:37.

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                        • Originally posted by Firestorm View Post
                          It is a compound delta actually. The sweepback angle at the front wing root is lower than the angle for the rest of the wing. Exactly the opposite of the cranked arrow design of the Saab Draken.

                          The naval version has movable LEVCONS.
                          Modern super-computers and advanced design can tweak a delta wing and improve it, but inevitably it will still demonstrate some of those attributes. Don't get me wrong, it's not a bad design, and has some strengths, like low drag, excellent acceleration, high top speeds. In these days of point & shoot missiles, the need to sustain a lengthy turning fight is less important than it was in 1980.

                          The MiG-21 is not pure a delta, but the shape of its wing also gave it some delta tendencies. A-4, same.

                          Stitch's explanation of turn rates was spot on. As for the area rule, it turned the dog that was the prototype F-102 into the much more acceptable production F-102, and then the more refined F-106. Look at the fuselage of the F-106 vs. the early F-102. Simply following the area rule created a vastly superior jet by reducing transonic and supersonic drag. The prototype F-102 could barely go supersonic; the F-106 did so with ease.



                          F-106, more pronounced "wasp-waist".


                          On some other aircraft like the T-38, the area rule produced beautiful lines. Note the air ducting pinching in proportionally to the wing span:


                          More modern fighters still follow the area rule, but the rule has been refined, and you don't have the obvious fuselage pinching that you do on the earlier jets. A shame, because the more simplistic area rule jets have beautiful, "womanly" curves.

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                          • My favourite example of "area rule":
                            Blackburn Buccaneer

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                            • Originally posted by Chogy View Post
                              The prototype F-102 could barely go supersonic; the F-106 did so with ease.
                              Not only supersonic, but double-sonic. Of course, the fact that it had the more powerful J-75 didn't hurt, either!

                              BTW, good example of area-rule with that photo of the F-5, it really emphasises what area-rule is.
                              "There is never enough time to do or say all the things that we would wish. The thing is to try to do as much as you can in the time that you have. Remember Scrooge, time is short, and suddenly, you're not there any more." -Ghost of Christmas Present, Scrooge

                              Comment


                              • Originally posted by Defcon5 View Post
                                Hitesh,

                                There is a inherent flaw in LCA, It is its air flow. That is not going to change without serious redesign, might as well as make a new light combat aircraft. 1 Rafale doesnt equal 5 LCA. With a foreign engine, foreign AESA etc also adding the R&D cost, it might half the cost of a Rafale or at most 2 Rafale's.

                                I am not going against your assertion for a plane 'like' LCA, but rather LCA itself. It is currently in a half baked form, but I am not blaming anyone, making aircraft industry from scratch is no child's play. But is that enough of a reason for IAF to order 350 LCA's, I doubt it.
                                Interestingly, Saab is still in India with it's Gripen NG, in spite of losing the MMRCA deal. I have been wondering, if they stay there in case the LCA is delayed "too much" or if it's costs increase by too much.

                                One should also note that the engine for Gripen NG is F414G; I do not know how different it is from the F414IN that has been ordered for the LCA but since both are for single-engine fighter jets, my guess would be that they are not that different, and if there are any differences then perhaps those can be handled.

                                So perhaps India orders 90 Gripen NG without engines... ;)
                                Last edited by Loke; 19 Feb 12,, 09:18.

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