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Light Stealth Aircraft

Discussion in 'Indian Air Force' started by randomradio, Mar 19, 2016.

  1. Grevion

    Grevion Professional Think TROLL ELITE MEMBER

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    When vstol says he can deliver the LSA in 4 years....it he talking about the first prototype or the LSPs??
    If its the prototype then supposedly flight tests and certification takes another 4-5 years till 2028, the LSA could very well be challenging the existence of a 4.5 gen LCA post 2030.

    Ps- I still can't believe that you changed your dp to something so hideous.:D
    The bigger question - will IAF accept any such aircraft post 2030?

    Chai Nashta.
    While HAL have proved their metal in the rotary wing aircrafts they are certainly lagging behind in the fixed wings category.
     
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  2. Immanuel

    Immanuel 2nd Lieutant FULL MEMBER

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    Apart from the F-16 which is too old to be inducted into the IAF, the rest of the line up is pretty good. MII with imported aircraft for both single and twin engine contests only proves this Govt. is trying to find a different way to do the same thing. Waste of time and currency including the measly order of Rafale. I would rather they invest in your aircraft for instance and make it happen in 8-10 years.
     
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  3. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    I once again reiterate that development time for LSA will be just four years and first squadron delivered within that time. Please read about the M2K development. If you use already proven airframe/avionics, you can create a new aircraft within 24 months.
    https://en.wikipedia.org/wiki/Dassault_Mirage_2000
    "The prototype made its first flight on 10 March 1978. Despite all the new technologies applied, basing the new aircraft on the Mirage III allowed the development of a prototype in only 27 months from the program start to the first flight"
     
    Last edited: Feb 17, 2017
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  4. randomradio

    randomradio Mod Staff Member MODERATOR

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    He is talking about first squadron of fighters in 4 years.

    First flight is 2 years after go ahead. 1 year to have it certified for production. And then build the fighters while it is going through the final year of development tests.

    http://indiandefence.com/threads/f1...s-and-possibilities.56222/page-61#post-528998

    LSA will challenge the need for AMCA also. And of course, even Rafale and the SE MII.
     
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  5. Immanuel

    Immanuel 2nd Lieutant FULL MEMBER

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    Regardless, development, testing and clearance for production for an Indian implementation will never be less than 8 years. You can reiterate all you want. Your air frame is not proven, regardless of how much your design is similar to Marut, it is as far as the user is concerned a new type and if you intend it for to be used by IAF/IN, then this process will be longer. It'll take you a couple of years just to negotiate the avionics and other requirements, everything from nuts and bolts have to be supplied as well. Moreso, testing will be done at some of the toughest conditions in India, again you expect from day one things will go smooth, I can't roll my eyes harder on this. Get real!

    Moreso, you developed it based on your idea of what is required wait till IAF and IN throw in their first requests of change. It's one thing to have a prototype ready in 27 months when done by an industrial giant with a fully established supply chain and suppliers a totally different thing when it needs to be done in the form of a consortium in India where such an advanced supply chain doesn't exist.

    I can go on and on, until you have a major industrial partner or consortium and the Govt. funding you, this won't happen. I wish you the best but you need to wake up. For one, wasting time on this forum won't help either.

    I maintain 8-10 years if things work rather smoothly
     
  6. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    AND I maintain 4 yrs for delivering first squadron. We can always agree to disagree. No heart burn on that.
     
  7. Sathya

    Sathya Lieutenant FULL MEMBER

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    LSA will give more than AMCA capability very fast.. In fact faster than along MK1A let alone MK2..

    But AMCA is required to develop indigenous technologies...
    We cannot depend only on off the shelf technology..
     
  8. Grevion

    Grevion Professional Think TROLL ELITE MEMBER

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    2 years!! That is mighty fast. Is 1 year enough for flight testing and validation?? Makes me wonder if our HAL/ADA guys are really incompetent.:frown:
     
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  9. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    A new aircraft has to undergo basically four phases of flight testing and they are:-
    1. Proving the hardware design & sub systems of the aircraft as a war fighting platform like the weapon bay doors operations and its ability to safely deploy weapons from the internal bays including FCS laws and safe weapons separation from wing pylons and safe operations from SBTF in all configurations including arrested landings. I plan to make the first prototype in twin seater configuration which will be slightly heavier than the fighter. Using this prototype to prove the hardware will help us reduce flight test time for fighter and save money.

    2. Proving the Software associated with sensors and weapons. I plan to use the system architecture of Rafale/Typhoon for LSA to avoid wasting time in integrating and proving various weapon systems and their integration in LSA system architecture. The longest time taken for integration for LSA will be its Radome. I plan to outsource this job to the vendor who will supply the Radar for LSA. Let the vendor modify any small aircraft nose with radome of LSA and complete the software refinements to ensure most optimum performance of the radar for LSA.

    3. Weapon Trials to prove the ability of the platform to use the weapons. I plan to have the prototypes of single seat fighters in actual operational configuration to expedite this stage of testing. This will help us save time, money and effort. Rafale was developed with just four prototypes for French AF & Navy. LCA fiasco should not be used as a bench mark for LSA. LCA prototypes have been retired and reduced to static displays like the phased out aircraft of Indian armed forces even before being used as a weapon of war. LCA should be taught as a case study in business schools in India as how to ruin a major program of national importance.

    4. Data generation for Safe Operations-This phase starts from first flight and continues till all the data needed for entry into service has been compiled for normal & emergency operations of the aircraft with varied weapon loads, configurations and emergencies etc.
    The serial production of the aircraft can be under taken after the completion of first stage of testing. Gnat, M2K, F-35 are examples wherein the production of the aircraft started after the first stage and in case of F-35, about 120 aircraft have been delivered to four different nations including Israel while the aircraft has yet to achieve FOC.
     
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  10. Grevion

    Grevion Professional Think TROLL ELITE MEMBER

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    Thank you sir for the kind and detailed reply. How many prototypes are you planning to build before freezing the final configuration?
    Also in case of the F-35 one of the hardest criticism the whole program faces is that the Pentagon/Boeing started the production of aircraft without testing it fully in the final configuration. I hope that's one area where you'll be wary of all the possible problems that could occur while the LSA is being developed.
     
  11. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    LSA will undergo not only CFD and wind tunnel analysis but also Hydrodynamic analysis prior to freezing the prototype production design. LSA relies on vortex lift and it shows up best only in hydrodynamic testing. F-35 problems were also noticed in hydrodynamic testing.
     
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  12. randomradio

    randomradio Mod Staff Member MODERATOR

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    HAL/ADA chose a RSS design, that takes time to test. And they are developing avionics from scratch. LSA is not doing both.
     
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  13. Grevion

    Grevion Professional Think TROLL ELITE MEMBER

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    Sir please elaborate what is vortex lift and how does LSA relies on it.
     
  14. somedude

    somedude Captain FULL MEMBER

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    If you generate a controlled vortex over the wing, it improves lift and delays stalling. See this for a general explanation of how vortices can be useful. Vortex lift can be generated by a number of methods, including LERX, close-coupled canards, and others.
     
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  15. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    Vortex lift is the predominant lift for swept wings and if the design has LERX/Chine/Strakes. It is more dependent on modifying the airflow on the upper surface of the wing. Just to give you a small example. two wings with same wing area, aspect ratio and Reynolds number will act differently based on the sweep angle. When you compare two wings, you need to create a wing with similar parameters with zero sweep and with sweep as required by your design. Both wings will have same value for stalling CL but modified by the Cosine of the sweep angle. Cos zero is 1 and Cos90 is zero. As the sweep angle increases the lifting capability of a wing reduces and to generate more lift it needs to pull higher alpha value. But something remarkable happens when you hit sweep angles beyond 40*. The leading edge of the wing starts to produce rolling airflow. The rolling airflow tends to concentrate in small vortices which energise the boundary layer on the upper surface of the wing and break down close to stall alpha and suddenly destroy the lift. LERX/Chine/Strakes are a way to keep them attached to the upper surface boundary layer to keep it energised and prevent separation of airflow which will cause the wing to stall. Very high sweep angles result in very high alpha control but also reduce the lift as per the cosine of the sweep angle and fail to generate the additional lift. It has been found by many experiments that there is a correlation between the strength of vortices and sweep angle which produces finest lifting ability. This requires the vortices to have a sufficient strength and vortex velocity. Vortex velocity is the velocity within the core of the spiral of airflow created by the sweep angle of the wing. Higher sweep increase this vortex core velocity but also reduces the overall lift of the wing due to the cosine factor. 50* sweep has been found to be the best sweep angle which provides a perfect balance between the strength of the vortices, vortex core velocity and also the cosine factor of lift due to sweep.
    LSA has 50* sweep, LCA has 50* inner sweep and 62.5* outer sweep. LCA will be an excellent platform if they reverse it. HF-24 had 50* sweep and it increased to 51.5* on the outer wing to give aerodynamic washout to provide adequate stall warning and prevent wingtip stall.
    LSA in addition has CHINE, yes Chine and not LERX what you have seen in the designs that I have posted. But it has very prominent Chines which enhance the lift by over 50%. The length of those Chines has been calculated to ensure that lift augmentation starts from 4* alpha onwards and at 16* alpha the value of lift generated by LSA wing will be same as that of a straight wing with zero sweep. It was a very complex process and took me over one year but I got the value of the aspect ratio & wing area for the Reynolds number I chose for the wing correct. The location, length, area and shape of Chine/LERX also plays a very big role in overall performance of a wing. The other problem was finding a harmony between the wing and the fuselage. I finally got that also right. Many members who think that LSA will start after the go ahead do not know that I have done lot of work which normally takes over two years to design an aircraft.
     
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