LCA Tejas: News and Discussions

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Indranil
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Re: LCA Tejas: News and Discussions

Post by Indranil »

Meanwhile, on FB:
Question) Tejas - LCA, I know that the fuel flow proportioner on Mk1 restricts the movement of CG within 1% of MAC. This was true for fuel drawn from internal fuel tanks. Is this also true with external fuel tanks?
Tejas - LCA No.
Question) Another question related to CG. Is Mk1 still flying around with a 300kg ballast. Or is this a modern myth?
Tejas - LCA Flies with ballast but the no is not this big in number.
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Re: LCA Tejas: News and Discussions

Post by member_28932 »

sbhatia wrote:first of all let me wish all the forum readers here a very happy and prosperous 2016... Now, about tejas-news... a few points reported elsewhere thought of sharing it here..BTW my name is changed my admin already though i prefered dr@gon :twisted: .

1.flight-envelope of tejas is gradually being opened up -- and that tejas is presently pulling beyond 8g and 24+ degrees of AOA maneuveres... You may expect these to be opened up still further as tejas now races towards its FOC

2. As reported elsewhere, SP2 is currently getting check-outs -- will be handed over to IAF soon...

3. As per reports, Mr Shuvana Raju, HAL chief, and Mr Sridharan, in charge of tejas assembly line, have been quoted to have confirmed that most (43 of 57, including IFR, Quartz radome, gun, BVR capability, multi-rack, pod-based EW suite, etc) ASRs have already been sorted out and will be incorporated from SP5/6 onwards... And, mk1A will additionally have ELTA2052, 800 kgs of weight-shedding and internal rearrangements for better maintainability...

4. The Elbit DASH-3 Helmet mounted display & ELTA2052 "combo" will help the tejas pilot to fire BVR-missiles at targets within most combat ranges just by merely seeing those by the preceding manner... mk1A will be a beast of fighter and would be able to take care of any ACs our potential enemies can field against us in near future...

5. Finally, let tejas fly non-stop to Bahrain from Bombay to participate in the 4th edn of the Bahrain Airshow...


Personally 800 Kgs of weight reduction i am skeptical but hopeful that it would work out as this would turn mk1A into a beast :)
You forgot to quote the one of the most important parameter which is Aerodynamic improvement which will improve trans-sonic acceleration by 20% and 2% rise in max speed. Compact Electronic component and rearrangement LRU will liberate some space for additional fuel. Aerodynamic improvement and additional fuel will push range upward so as fuel efficiency. Wing redesign and air intake redesign are also discussed a lot. I am awaiting for and authentic news in this area like the Aerodynamic improvement. Tejas is moving ahead in the direction of its intended capabilities and specification. Vivek Ahuja in his article of simulated comparison of Tejas and F 16 has clearly written that any weight reduction in tejas from this stage shall give a big rise in the performance of the aircraft. I want to see tejas a Mach 1.8 aircraft. With the passage of time, we will see a lots of improvement in this Aircraft as we show in Dhruv, Rudra and LCH. Tejas will emerge as the India specific fighter designed exactly as per our requirement and meet all our requirement like dhruv. A big big order is bound to follow.
Last edited by member_28932 on 06 Jan 2016 08:58, edited 1 time in total.
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Re: LCA Tejas: News and Discussions

Post by member_28932 »

Dileep wrote:Is the 300kg ballast still there? Are you sure? Positive?

Asking because it was there long time ago during the TD days, to bring the CG forward, to make the plane stable. I see no reason for it to be there currently. Any ballast present would be precisely substituting for a piece of equipment that is planned there, like a heavier radar. So, if they are planning the 2052, which is around 80kg heavier (assuming the numbers posted above), there will be an 80kg ballast to substitute.

OTOH, if they are actually still flying a 300kg ballast for nothing, other than for the reason they are incapable of using that weight for some productive purpose, I should stop following these threads. NAY... I should also stop pestering these entities to get a piece of the action into my KB.
Ballast become necessary to compensate the increased weight of landing gear than what they were designed for. Now they are planning to reduce the landing gear weight there shall a shift in CG Upward automatically and which shall facilitate removal of ballast. By rearrangements of LRUS, some space is generated in front size which shall be used to add atleast 50 to 55 kg of additional fuel. This shall also compensate for ballast weight i front area. AESA shall also be bit heavy compared to EL 3032. The electronics components are also getting compact. This will not have a big effect on weight but they should liberate valuable space to rearrange LRUs or accommodate more fuel etc. Over a period of time , we shall see more and more merging of LRUS which shall result in lower wright and compact in size. I believe that we need to spend some more money on R & D of tejas. Any improvement from this stage should have a big impact in performance of tejas from this stage. NEw composites are also coming up which are light in weight. There are some more components which are planned to be made from composite rather than metal. This wight reduction is a multidimensional approach and we are working on many front.
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Re: LCA Tejas: News and Discussions

Post by shiv »

Dileep wrote:OK, so the F-15 have it, but apparently there is a specific reason for that. It is not a fly by wire plane, and it needed to balance the stability and maneuverability, so it has a type tuned ballast. Each type version have a different weight of ballast apparently (because I see weight figures all around the park).

Does any of the f teens have it? Can't find any ref on chacha. Does the euros have, except the legendary concrete block in the typhoon?

Anyway, it doesn't make sense, at least to me, that our 6.5 tonne craft with inherently unstable platform and digital FBW will need a ballast of 300kg. Also, we KNOW that the 300kg ballast was for the TDs, to make them deliberately stable.
I searched kookal for this yesterdin.

F-16 specifically have had temporary (not permanent) ballast in place of gun. I also recall reading that the ever present wingtip missiles act as dampers (I don't know if that is the word) that reduce G-stress bending of wings helping to extend their fatigue life.

More generally it does appear that is existing equipment can be moved to take the place of permanent ballast then the ballast itself leaves a vacant space that can be used for a useful payload (eg fuel)- thus explaining what was met with incredulity on BRF (I think) when someone asked how eight can be saved by moving things around.
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Re: LCA Tejas: News and Discussions

Post by Wickberg »

indranilroy wrote:Yes, static margin management matters a lot.

Designers put in ballasts for missing hardware which they are somewhat sure of coming on board pretty soon. In other cases, ballasts are used on special purpose airplane to compensate for removed/replaced or added components. None of these is the case with LCA.

LCA designers were dealing with enormous uncertainties. They were learning to design and manage a project with no existent expertise. Imagine yourself in their shoes. You are trying to design and develop a plane which way out of your league. You have to learn on the job, as frugally as possible, where funding is at the mercy of a babu who passed an administrative exam. Nothing is sure: the engine, the radar, the landing gear, the fuel system, the structures, the environment control systems, nothing. What's more all you have is your resolve to learn with somebody else, who may be interested in building a complex part. You both learn together, till he reaches a maturity where he thinks he can manufacture the part. But there are 100s of such parts. Some you know will take a couple of decades to come through. Some you know is unlikely to happen. But then people surprise you. Not only have they come up with a part, but they are better than what you expected. In some cases you learn that your expectation was wrong. You re-calibrate. Can you imagine designing a 4.5 gen plane amongst all these uncertainties. What if only 10% of the components come out differently than what you expected? What do you do? The basic structural design was finalized a decade back! You have to go for ballasts.

It is more likely than not, that LCA is over designed. May be if the designers started today with the advantage of 20:20 hindsight, they would be able to shave 500 kgs off the plane. That is why they want to do the Mk1A and Mk2. And that is such an important difference in the LCA program today and 3-5 years back. Actually, I don't blame the UPA govt. on the support for LCA. Anthony did stick up his head against the IAF for LCA. Those were the days where the IAF-chief openly called it a 3-legged Cheetah on the day of certification of LCA. Can you imagine? The difference with Parrikar is that unlike Anthony, he cracks a whip. He understands that manufacturing is a necessity for the program and has forced IAF to oblige. To be fair to Anthony, Parrikar has the advantage of hindsight, a much more mature product, and a more cornered IAF.

By the way, as I dig deeper into the ballast issue on LCA, it seems like it has a 180 kg ballast placed ahead and below the feet of the pilot. Some of this will go with an heavier radar. A little more may be chipped away with the IFR probe. We may be left with almost no ballast on the Mk1A with rearrangement/optimization of the LRUs/LGs. Lets see.

Mk2 will definitely challenge Gripen NG. SAAB knows this and is doing everything to sabotage the LCA program.
Wow, to you it sounds like the Indians have just invented the flyingmachine and it´s really amazing or something. Imagine if an nation of 6 million people had done something like what you descreibed 60 years ago and would had been evenly shocked about it. Like the fighter SAAB 35 Draken, who had a uniqie and untested design. But much more important to, it flew (just the LCA have done) it came in service and behold; it was even exported to other countries. Now, in Sweden, this was not considered a huge sucess or people got overlyexcited about, it was just a plane that did its job. I wonder how you will feel when/if the LCA ever becomes operational service. BTW, the Draken came in service in 1960 as the first fully Mach.2 fighter in western Europe. The last operator,Austria, took it out of service in 2005, thats 20 years after the LCA-project had started. So no I don´t think any hypythetical Mk2 will pose a challenge to anything. Let just get the LCA into service first, within the next 20 years or so...
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Re: LCA Tejas: News and Discussions

Post by member_29268 »

So, would it be correct to say that we have established it takes a team of less than or equal to 6 million to design a fighter aircraft. Great !! :)
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Re: LCA Tejas: News and Discussions

Post by BharadwajV »

Wickberg wrote:
Wow, to you it sounds like the Indians have just invented the flyingmachine and it´s really amazing or something. Imagine if an nation of 6 million people had done something like what you descreibed 60 years ago and would had been evenly shocked about it. Like the fighter SAAB 35 Draken, who had a uniqie and untested design. But much more important to, it flew (just the LCA have done) it came in service and behold; it was even exported to other countries. Now, in Sweden, this was not considered a huge sucess or people got overlyexcited about, it was just a plane that did its job. I wonder how you will feel when/if the LCA ever becomes operational service. BTW, the Draken came in service in 1960 as the first fully Mach.2 fighter in western Europe. The last operator,Austria, took it out of service in 2005, thats 20 years after the LCA-project had started. So no I don´t think any hypythetical Mk2 will pose a challenge to anything. Let just get the LCA into service first, within the next 20 years or so...
Can you please rant on a free Paki site or something?
I'm sure that you will be much appreciated there.
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Re: LCA Tejas: News and Discussions

Post by member_28990 »

Wickberg wrote: Wow, to you it sounds like the Indians have just invented the flyingmachine and it´s really amazing or something. Imagine if an nation of 6 million people had done something like what you descreibed 60 years ago and would had been evenly shocked about it. Like the fighter SAAB 35 Draken, who had a uniqie and untested design. But much more important to, it flew (just the LCA have done) it came in service and behold; it was even exported to other countries. Now, in Sweden, this was not considered a huge sucess or people got overlyexcited about, it was just a plane that did its job. I wonder how you will feel when/if the LCA ever becomes operational service. BTW, the Draken came in service in 1960 as the first fully Mach.2 fighter in western Europe. The last operator,Austria, took it out of service in 2005, thats 20 years after the LCA-project had started. So no I don´t think any hypythetical Mk2 will pose a challenge to anything. Let just get the LCA into service first, within the next 20 years or so...
in other news, the grapes are sour :rotfl:
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Re: LCA Tejas: News and Discussions

Post by shiv »

Wickberg wrote:
Wow, to you it sounds like the Indians have just invented the flyingmachine and it´s really amazing or something. Imagine if an nation of 6 million people had done something like what you descreibed 60 years ago and would had been evenly shocked about it. Like the fighter SAAB 35 Draken, who had a uniqie and untested design. But much more important to, it flew (just the LCA have done) it came in service and behold; it was even exported to other countries. Now, in Sweden, this was not considered a huge sucess or people got overlyexcited about, it was just a plane that did its job. I wonder how you will feel when/if the LCA ever becomes operational service. BTW, the Draken came in service in 1960 as the first fully Mach.2 fighter in western Europe. The last operator,Austria, took it out of service in 2005, thats 20 years after the LCA-project had started. So no I don´t think any hypythetical Mk2 will pose a challenge to anything. Let just get the LCA into service first, within the next 20 years or so...
I'm sure you'll love this video:
https://www.youtube.com/watch?v=UoV-Xx3B8NM
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Re: LCA Tejas: News and Discussions

Post by Karan M »

^^ He got an ouchie..the poor 'un. :rotfl: Nation of 6 million people who were busy acting like NATOs munna and sitting on Nazi gold. Nice way to fund all toys, shoys.
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Re: LCA Tejas: News and Discussions

Post by Neela »

IR's insightful post VS a juvenile rant.

Looks like cold naked facts on the Gripen Engine was really really bitter for poor Wickberg to swallow and he is lashing out.
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Re: LCA Tejas: News and Discussions

Post by Karan M »

Shivs video is also heating up the unmentionables of the Gripen gang. "Fake video" :(( :((

LOL
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Re: LCA Tejas: News and Discussions

Post by JayS »

Dileep wrote:OK, so the F-15 have it, but apparently there is a specific reason for that. It is not a fly by wire plane, and it needed to balance the stability and maneuverability, so it has a type tuned ballast. Each type version have a different weight of ballast apparently (because I see weight figures all around the park).

Does any of the f teens have it? Can't find any ref on chacha. Does the euros have, except the legendary concrete block in the typhoon?

Anyway, it doesn't make sense, at least to me, that our 6.5 tonne craft with inherently unstable platform and digital FBW will need a ballast of 300kg. Also, we KNOW that the 300kg ballast was for the TDs, to make them deliberately stable.
Why you find it so hard to believe?? Think about it for a min. A ballast of about 200kg (its about 200kg and not 300kg, IR also quoted 180kg above.) in the nose region (far away from the CG) is pulling the CG forward significantly. A rough back of the envelop calculations tells me that it would pull CG by almost 3-4% of mean aerodynamic chord (MAC). How much unstable LCA is in terms of static margin? 5% nominal. So its very significant movement from the static margin POV. If you don't use ballast you end up with nominal ~8-9% static margin which is quite close to/beyond the limit that current FCS technology (production fighters only not including research platforms) can handle comfortably. (~8% is practical limit due to actuation speed limits).

300kg ballast used in TD for making it stable is believable. But this does not mean current ballast can be eliminated just like that. There are many many configuration differences in TDs and the later prototypes. I am sure ADA would have tried hard to remove it.

Also there is no need to verify each and everything from west for something to make sense. Each aircraft is unique with its own set of challenges, with its own set of solutions.

Vipul Dave wrote:
Ballast become necessary to compensate the increased weight of landing gear than what they were designed for.
Can you please quote a reference for this??
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Re: LCA Tejas: News and Discussions

Post by Karan M »

Indranil, looks like the FB LCA page is managed directly by one of the TPs or engineering crew. Curt, access sensitive replies.
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Re: LCA Tejas: News and Discussions

Post by shiv »

Karan M wrote:Shivs video is also heating up the unmentionables of the Gripen gang. "Fake video" :(( :((

LOL
As I always say - everyone is free to make his own fake video and put it up - these things are easy to say but more difficult to fake. Go ahead and fake a video so we can also have the pleasure of seeing one.
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Re: LCA Tejas: News and Discussions

Post by Karan M »

Shiv, a picture counts for a thousand words and a video for ten thousand. Your work is lighting up the fire below the behinds of a lot of these jokers who toot their own horn based on dodgy claims. Please continue.

The above LCA video shows how close both aircraft already are in terms of the performance at that speed.
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Re: LCA Tejas: News and Discussions

Post by JayS »

Saurav Jha ‏@SJha1618 Jan 4 New Delhi, Delhi
Final Operational Clearance for the LCA MK-1 will happen this year. It will happen in the last quarter of 2016. That's the realistic date.
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Re: LCA Tejas: News and Discussions

Post by member_28990 »

From LCA Facebook page
Tejas - LCA MK1A will primarily address the maintenance issues plus the gun integration, AESA radar integration, BVR integration (whenever IAF gives a clear indication on the kind of BVR) etc..
this is extraordinarily surprising
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Re: LCA Tejas: News and Discussions

Post by Karan M »

Why? IAF specified Derby ER (per reports) for Tejas Mk1. What if they want Meteor for Tejas Mk1A given AESA? Or Astra Mk2. Point is SOP for Mk1A may be different from Mk1.
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Re: LCA Tejas: News and Discussions

Post by srai »

Astra Mk.1 should be the preferred option for LCA Mk1A IMO.
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Re: LCA Tejas: News and Discussions

Post by Karan M »

If Mk2 is ready by then...or in trials, it'll be good to have that too. IMHO, what the FB page is saying is IAF is yet to specify all the missile/s they want for BVR.. the radar and some items are fixed.. but some things IAF may need to specify yet.

Nothing surprising per se..
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Re: LCA Tejas: News and Discussions

Post by JTull »

I get the feeling that IAF is delaying LCA Tejas to get more Rafales or other imported stuff.
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Re: LCA Tejas: News and Discussions

Post by Chinmayanand »

maxratul wrote:From LCA Facebook page
Tejas - LCA MK1A will primarily address the maintenance issues plus the gun integration, AESA radar integration, BVR integration (whenever IAF gives a clear indication on the kind of BVR) etc..
this is extraordinarily surprising
If forces have to fight, it has to be with only imported maal. Short dark rice variety local maal will not do. And i am running circles why the politicos don't act like Rambo after terrorist attacks.
Politicos may not react because forces are not prepared. Forces are unprepared because there is not enough imported maal. There is not enough imported maal because there is not enough money to buy imported maal plus kickbacks. Hence, the talk of bigger economy.
Pieces falling in place perhaps.
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Re: LCA Tejas: News and Discussions

Post by Karan M »

nileshjr wrote:Saurav Jha ‏@SJha1618 Jan 4 New Delhi, Delhi
Final Operational Clearance for the LCA MK-1 will happen this year. It will happen in the last quarter of 2016. That's the realistic date.
Is this Jhas estimate??
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Re: LCA Tejas: News and Discussions

Post by deejay »

maxratul wrote:From LCA Facebook page
Tejas - LCA MK1A will primarily address the maintenance issues plus the gun integration, AESA radar integration, BVR integration (whenever IAF gives a clear indication on the kind of BVR) etc..
this is extraordinarily surprising
What is this guys. I get the mandatory IAF bashing but Gun integration on Mk 1A? There is no gun on Mk 1?
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Re: LCA Tejas: News and Discussions

Post by JayS »

Karan M wrote:
Is this Jhas estimate??
Can't say. Might be his own estimate. Might be something he heard/is told. Some report posted earlier claimed delay in FOC due to Bahrain airshow preps as well.
deejay wrote:
maxratul wrote:From LCA Facebook page

Tejas - LCA MK1A will primarily address the maintenance issues plus the gun integration, AESA radar integration, BVR integration (whenever IAF gives a clear indication on the kind of BVR) etc.

this is extraordinarily surprising
What is this guys. I get the mandatory IAF bashing but Gun integration on Mk 1A? There is no gun on Mk 1?
Could be a mistake. MK1 without Gun is ridiculous.
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Re: LCA Tejas: News and Discussions

Post by Indranil »

Wickberg wrote: Wow, to you it sounds like the Indians have just invented the flyingmachine and it´s really amazing or something. Imagine if an nation of 6 million people had done something like what you descreibed 60 years ago and would had been evenly shocked about it. Like the fighter SAAB 35 Draken, who had a uniqie and untested design. But much more important to, it flew (just the LCA have done) it came in service and behold; it was even exported to other countries. Now, in Sweden, this was not considered a huge sucess or people got overlyexcited about, it was just a plane that did its job. I wonder how you will feel when/if the LCA ever becomes operational service. BTW, the Draken came in service in 1960 as the first fully Mach.2 fighter in western Europe. The last operator,Austria, took it out of service in 2005, thats 20 years after the LCA-project had started. So no I don´t think any hypythetical Mk2 will pose a challenge to anything. Let just get the LCA into service first, within the next 20 years or so...
1. Actually, you are right about many things. First of all, I greatly admire Sweden as a country and its human resource development. It is a lesson for India to learn. However, the Sweden model cannot be implemented in India: for logistical reasons, economic reasons, and geopolitical reasons. However, we should incorporate some of the strategies for higher education implemented in the Euro region. Secondly, I love it that your regions fosters skill holders rather than degree holders. But, that is my opinion. There are a billion other opinions in India.

2. You think LCA is a big deal for Indians. That is not true either. An average Indian doesn't know, doesn't care. Worse the average Indian will join you in criticizing the project. I invite you to the streets of India. Defence forumites are an infinitesimally small percentage of our population.

3. Draken was a great plane, and a great project. But the only significant challenges faced by the engineers were technological challenges. That is not the case with LCA. There is a saying that many things in India succeed despite the govt. and the bureaucracy. For ADA (the designers of LCA), their prime user (IAF) antagonizing the govt. on many steps against the LCA. Their production agency was acting as a laggard to say the best. And if that was not enough, they lost years of work on flight control when they were locked out of a US facility, where they were carrying our development and testing. Their machines, notes, computer programs and even personal belongings confiscated. They could not, and still cannot import many parts. The same institutes from which they are supposed to draw resources, looked at them as competitors and slowed them down. They could not consult experts from Pakistan, Bangladesh, Nepal, China, or Srilanka. And nobody would be satisfied if they came up with a Draken first, or even a GRipen A/B in their first attempt. They are being judged for not building a Gripen NG in their first attempt!

4. Now Gripen NG is a great plane. But it would be impossible to come with such an optimized flying machine, without a base design, research facilities, testing facilities and industrial base. LCA Mk1 is not Gripen NG. But designing and building LCA has allowed Indians to learn the lessons and build the infrastructure required to build a Gripen A/B, leapfrogging over the development of a Draken. Now, we are on the path of building a Gripen NG equivalent. And in that we get there, we will be competing. Whether you like it or not. Whether you acknowledge it or not!
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Re: LCA Tejas: News and Discussions

Post by Kartik »

Indranil, you're wasting your time on this numbskull. He regularly resurfaces and then disappears and one can safely ignore his type. All Swedes aren't as daft as this chap.
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Re: LCA Tejas: News and Discussions

Post by ramana »

deejay, remember the discussion on the A3 sheet with holes and one side being tighter than other? I had asked about the g levels due to the firing and impact on the LRUs. No answers.

Probably some of the LRUs are being requalified and Mk1 will have old LRUs!

So Mig21 dejavu/all over again.

The AAM better work.
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Re: LCA Tejas: News and Discussions

Post by sudeepj »

Simple pooch. Conformal Fuel Tanks, below the wing root or above the spine for LCA.. Doable?
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Re: LCA Tejas: News and Discussions

Post by ramana »

Redo the flight tests all over again.
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Re: LCA Tejas: News and Discussions

Post by sudeepj »

ramana wrote:Redo the flight tests all over again.
Quite a significant undertaking! My question is more on the lines of physical possibility.. These can be done at a later date when the fighter is in service.
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Re: LCA Tejas: News and Discussions

Post by abhik »

sudeepj wrote:Simple pooch. Conformal Fuel Tanks, below the wing root or above the spine for LCA.. Doable?
I don't think CFT under the wing root will be possible because of how the landing gear is set up.
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Re: LCA Tejas: News and Discussions

Post by Indranil »

sudeepj wrote:Simple pooch. Conformal Fuel Tanks, below the wing root or above the spine for LCA.. Doable?
I don't think that they will go over the wing root, but under the wing root is possible. Under the wingroot, it is not exactly a CFT. You basically build a bulged fairing into which you push out MLG and some of the LRUs. This creates additional space inside the fuselage for extra/larger fuel tank. This is what the Gripen NG does. The same is being done on the LCA NAvy Mk2.

However this comes at a price. If your plane carries more fuel and more armaments with essentially the same engine, it becomes heavier and more sluggish through the air. Also if it gets fatter, it increases your wave drag, something which ADA is trying to decrease on the MK2. Accordingly, ADA has only made the LCA IAF Mk2 longer, but not any fatter. According to my calculations, the fuselage tanks carries about 690-710 ltrs of usable fuel on Mk1. This is likely to double on Mk2, with the wing tank capacities remaining the same. LCA Navy is going to be 0.7 mtrs wider, 1.36 mtrs longer than the Mk1. It will also have the bulged fairing at the wingroot for the MLGs. This will make it significantly heavier than IAF Mk1. My guess is that its clean takeoff weight will be 10800-11000 kg range. This will make the LCA Navy Mk2 more sluggish than the LCA IAF Mk2. But, it will allow it to stay longer in the air.

The idea is simple. India is going to have light (LCA/Mirage), medium(Mig-29s/MirageRafale/AMCA) and heavy fighters(Su-30/FGFA). All of them truly multi-role and agile. But the wieght category will define their range and armament carrying capability.
Last edited by Indranil on 07 Jan 2016 22:28, edited 2 times in total.
Reason: Added highlights. ramana
sankum
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Re: LCA Tejas: News and Discussions

Post by sankum »

In medium category it should be Rafale instead of Mirage (Mig-29s/Mirage/AMCA).
Indranil
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Re: LCA Tejas: News and Discussions

Post by Indranil »

Thank you for the correction.
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Re: LCA Tejas: News and Discussions

Post by sudeepj »

indranilroy wrote:
sudeepj wrote:Simple pooch. Conformal Fuel Tanks, below the wing root or above the spine for LCA.. Doable?
I don't think that they will go over the wing root, but under the wing root is possible. Under the wingroot, it is not exactly a CFT. You basically build a bulged fairing into which you push out MLG and some of the LRUs. This creates additional space inside the fuselage for extra/larger fuel tank. This is what the Gripen NG does. The same is being done on the LCA NAvy Mk2.

However this comes at a price. If your plane carries more fuel and more armaments with essentially the same engine, it becomes heavier and more sluggish through the air. Also if it gets fatter, it increases your wave drag, something which ADA is trying to decrease on the MK2. Accordingly, ADA has only made the LCA IAF Mk2 longer, but not any fatter. According to my calculations, the fuselage tanks carries about 690-710 ltrs of usable fuel on Mk1. This is likely to double on Mk2, with the wing tank capacities remaining the same. LCA Navy is going to be 0.7 mtrs wider, 1.36 mtrs longer than the Mk1. It will also have the bulged fairing at the wingroot for the MLGs. This will make it significantly heavier than IAF Mk1. My guess is that its clean takeoff weight will be 10800-11000 kg range. This will make the LCA Navy Mk2 more sluggish than the LCA IAF Mk2. But, it will allow it to stay longer in the air.
Thanks Indranil for a great explanation! I think there may be other low hanging fruit before CFTs..
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Re: LCA Tejas: News and Discussions

Post by srai »

^^^

CFTs, for the most part, are for long-range strike. Less utility for anything else, especially air combat where lugging around that extra weight and drag would be detrimental to agility. LCA is a light fighter and not meant to do long-range strike. For that, the IAF has other more optimized platforms in medium and heavy fighters. Let's also not forget AAR capability being incorporated in LCA. Low priority if at all IMO.
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Re: LCA Tejas: News and Discussions

Post by member_29268 »

Adding to Indranil's explanation.

http://www.linnsideout.se/downloads/transfer-2008-3.pdf

Pages 19-21.
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Re: LCA Tejas: News and Discussions

Post by JayS »

^^ Good info. Thanks for that.


If I were LCA designer, I would look for more organic growth option at this stage rather than CFTs which is more like a patch work to extend utility of a platform at the end of its product development cycle when you are not willing to change much under the hood. What IR suggested is better way. I would focus on the kind of metamorphosis that mig-29 went through, where almost everything under the hood was refined/modified to make it better, as an MLU for MK1.

CFTs will not be of much help for the role that IAF envisages for LCA. May be in future it will change but there is enough time before that to go for more comprehensive change.
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