IDB SPECIALS: IS LCA A MINI-MIRAGE?

Look at both pics below:

To an novice (like me) who has little knowledge and interest in sports cars ,at very first glance it will be hard to differentiate between two, considering the fact there company logo is removed. But an keen follower of the same shall tell quite a lot of difference at the very first glance.

Same may happen when one looks at these folks:

When LCA and Mirage 2000 which are quite a formidable fighter in their own terms are vastly different from each other. We shall go one by one:

  • WINGS PLANFORM: Most common similarity as said by others but not exactly the same.
    • Mirage: Cropped Delta
    • LCA: Cropped Compound Delta
    • Inference: Pure Delta(Mirage:Cropped to reduce wing tip vortices to reduce drag same with LCA) has inherent problem of instability and low lift at slow speeds which compound delta addresses accordingly. It shall be discussed later in the answer.
  • Before going Further do have a look at the pic:

  • WING POSITION W.R.T FUSELAGE:
    • Mirage: Flat i.e 0* w.r.t to horizontol axis.

    • LCA: Anhedral

    • Inference: For Delta Wings Anhedral placement creates more lift, which further help to counter the lack of lift during slow speeds in tejas but thats not the case with Mirage, suffers lack of lift during slow speeds.
  • Extra LIFT AND PERFORMANCE INCREMENT DEVICES(Canards/LERX/Chine etc):
    • Mirage: Small strake on the intakes above wing.

    • LCA: Crank (Marked in pink and dihedrally placed)

    • Inference: Mirage doesnot have any Lift increment device, the strakes it uses it gives a littlehelp in maintaining airflow at high AOA but not very effective , unlike tejas whose dihedrally positioned forward swept crank helps it a lot to maintain lift at high angle of attack(AOA) by delaying flow separation above wings.
  • BLENDING WING : Look at wing- fuselage for junction both :
    • Mirage: The junction is clearly visible.
    • LCA: There is blending of juction between wing-fuselage.
    • Inference: Now this feature does two things-
      • Makes the fuselage self lift creating object.
      • Helps to reduce the RCS and add stealth to aircraft.
    • Mirage is in disadvantage in this one.
  • WING-LOADING : The lower the better. Lower wing loading is a key deciding factor about the maneuverability of aircraft. Lower wing-loading helps in better dogfight.
    • Mirage:337 kg/m²
    • LCA: 247 kg/m²

Now comes the most complex of all but rather ignored topic the INTAKES. The topic is scientifically very critical in deciding the performance of aircraft.

  • The position of inlet:
    • Mirage: Beside the fuselage.

    • LCA: Under and Behind wing.

    • Inference: Putting the inlet sidewise, creates airflow moving over the surface of the fuselage develops a turbulent boundary layer, and ingesting this turbulent boundary layer into the engines may causes problems in the compressors if not it adds to drag. Also at high AOA this position of inlets does not ensure a good performance but in case of tejas the position of inlet behind wind ensures a considerable of amount of air supply to engine at high AOA which is not in case of Mirage.

  • Type of Intake:Further the intakes of Mirage are old gen intake comprising inlet cone but which doesnot helps to guard the compressor RCS, but Tejas uses Y-Duct intake that curtails the compressor RCS and gives a big RCS reduction to tejas and adds to tejas’s stealth which is not the case with Mirage.

Above: Inlet cone of Mirage; Below: Y-duct inlet design.

Conclusion: Where Mirage was primarily developed to replace Mirage III it was supposed to be a interceptor and good ground attack capability which are the strong points of mirage but lacks little bit in Air to Air and Stealth capability whereas the LCA was always supposed to be point defense fighter to replace Mig-21 , hence it was supposed to have a well balance of ground attack, Air to Air combat and Stealth. Though LCA lacks in terms of range but thats a trade off between aerodynamics, stealth and attack capability just like the Mirage which does just the reverse. It’s all matter of priorities. The following points proves that LCA is not copy of Mirage-2000 either!

Pic credits: Google and Respective owner

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1 thought on “IDB SPECIALS: IS LCA A MINI-MIRAGE?

  1. RAVI KRISHNA IYENGAR December 20, 2017 — 2:40 pm

    The above talks only of aerodynamics and operations. it is silent on Maintainability. Unless the aircraft can be maintained by a lean crew, and turned around in the shortest possible time, the sortie generation rate would be very low, affecting operations. The Mirage has a high O level MTBF, a good MTTR and a very impressive MMH/FH. Just take the engine removal and installation time for a LCA as it is today and compare it with a Mirage. There is a sea difference in the timing. Combat aircraft should encompass not only op capability and aerodynamic features but the complete nexus of maintenance, TTGSE and other Supply chain parameters that go synergetically to make a complete weapon platform

    Like

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