LCA: News & Discussions: 15 August 2017

[Trikaal]

I don't think the GOI has even officially sanctioned funds so far for the Mk2 program. Unless funds get sanctioned, nothing can move off the drawing board.

[SaiK]

It is almost 8 years since we selected F414s (99 of them, with initial batch direct and subsequent ones CKDed). We are still arguing about the Mk2 program. Hope they get it started many of us oldie-jingoes die of age.

[srai]

LCA Mk.2 can be designed to match Mirage-2000 class “light-medium” specification since that is what the SEF import (F-16-70/Gripen-E) desires.

LCA Mk.1/1A can continue to replace MiG-21s in the “light” category.

[Austin]

Any information on Turbine Inlet Temperature ( TET ) of GE Engine on Tejas and the proposed 414 for Tejas Mk2 ?

[Indranil]

where Is the money to develop a prototype?

[brar_w]

Any information on Turbine Inlet Temperature ( TET ) of GE Engine on Tejas and the proposed 414 for Tejas Mk2 ?

Hard to pin down since officially these have not been provided. However upgraded variants of older gen US engines and more recent European engines are running with inlet temperature's in the 2460-2700'ish F iirc. If the data source is publicly available, or not classified, TEG at the F-16 site will be the best source to reach out to in addition to Guy Norris from AvWeek.

[Akshay Kapoor]

Indranil, my (perhaps stupid ) question is the foll

What are the main parameters where MK2 can be better than MK 1A. Intercept speed ? STR? , range ?

Wasn't the original thinking that it would rectify a lot of shortcomings of MK1 but now MK1 is so good that it doesn't have many shortcomings and it found after a lot of study that MK 2 would not give add much more so that's why it's been shelved.

From everything I've read I get the sense that the above is a vote of confidence in MK1 not the other way around. MK1 is admittedly as good as MIrage and okay for all our tactical needs in the western theatre and next steps is AMCA not mk 2.

[Thakur_B]

^^
- Increased Take off weight (rumoured to be 15.5 to 16 tons)
- Internal integral Jammer
- Increased range
- Payload comparable to Mirage-2000
- With empty weight believed to be within 10% range of Mk-1, the T/w ratio would make MiG-29 blush in A-A role.

[Akshay Kapoor]

^^
- Increased Take off weight (rumoured to be 15.5 to 16 tons)
- Internal integral Jammer
- Increased range
- Payload comparable to Mirage-2000
- With empty weight believed to be within 10% range of Mk-1, the T/w ratio would make MiG-29 blush in A-A role.

I'm very sceptical about this need for more payload for the tactical role it will have, and also the reasonableness of that need for a fighter of this class.

I remember reading a comment from ADA that increase in combat radius will be about 20 pct.

The t/w ratio is the only improvement that seems worthwhile. But I say that without knowledge of specifics so I may well be wrong.

And I doubt very much that all three of the above can be achieved simultaneously. If you go for payload then you negate the thrust/w increase for example.

Would love to hear the views of the experts. With specific number on the key parameters of poss. If these questions have already been addressed then my apologies.

[Indranil]

Akshay Kapoor sahab,

I am not an expert by any measure. It is a case of "aandhon ke beech mein kana raja" (Deaf leading the blind). I wish others here used Google more.

Mk2 will be more refined than the Mk1 in every way imaginable. For the same payload, it will have higher endurance, top speed, acceleration, turning rates.

Mk1A/1B (my nomenclature) can itself improve Mk1 performance.
1. A simple nose chine can improve the permissible AoA by 1-2 degrees: Faster instantaneous turn rate and better handling at slow speeds. Actually, on these two parameters, Mk1 is already one of the best out there. But it can do even better.
2. If 400 kgs can indeed be shaven off, that has an impact on everything. Given the time, they could qualify the fighter to 9G capable.
3. They have found out the the back of the canopy generates strong shocks at transonic and supersonic regions. A slightly more curved cockpit can reduce transonic drag significantly.
4. Similar changes can be done at the rear of the aircraft. Many do not understand why LCA has such large fairings for the flaperon actuators. It is not because they can't make them smaller. They reduce drag. They have found that they can reshape that for even better performance.
5. They are studying the ideal shape of the intake cowling for good pressure recovery around the entire flight envelop. And before others start jumping that Khokhar sahab already said so, this is way beyond that. What Khokhar sahab was pointing out was solved when they dropped the plan of powering LCA with Kaveri. They are now working in the sub 1% gain region now. There is no shape which would be ideal for the entire envelop. So they are thinking of having a top half shaped ideally for low subsonic and bottom half shaped ideally for transonic. Of course, the change is so minute, that is imperceptible to the naked eye.
6. Moving the outboard pylon to the wingtips should also reduce drag.
7. They can reshape the 1200 ltr tanks for 11% higher capacity, lesser drag and lesser interference with bombs carried on the midboard station.
8. In general, I am not a big fan of the space management of the underbelly section of LCA Mk1/1A. I don't understand why the fuel tank there is cylindrical? It should have been of elliptical cross section with a near 1200 ltr capacity to fully utilize that hardpoint. I know that they have already tested 1000 lb bomb there, but tandem pylon is not possible there. I tend to believe that neither is an LGB. The tail will scrape on TO and landing).
9. I have been thinking about this one a lot lately. They should take the internal gun out, and go for a podded gun like on the HAwk or the F-35 B/Cs. It will save them 100 kgs when the gun is not needed, make space for an internal SPJ, and open up an hardpoint there. Of all the things on my list, I would love to integrate Lockheed's Legion (IRST) pod.

10. If that is not possible A Tiger Eye like solution which incorporates the IRST in the pylon of the LDP can also be pursued.

11. Finally LCA needs some dual racks: parallel racks to carry two 2 500 lb lgbs in parallel. Tandem rack to carry two 500 lb bombs in tandem on the midboard pylon.Tandem-cum-parallel racks to carry four (2 behind 2) 500 lb bombs on the inboard pylon.

BY SOME STROKE OF LUCK, WE HAVE A DAMN GOOD FOUNDATION ON WHICH WE CAN BUILD A WORLD CLASS WEAPON SYSTEM. And that's why the powers that be are trying to scuttle it. With all countries making cuts in defense budgets, nobody wants to lose orders to the new kid in town. And that's why BIG MONEY is being spent. We should be careful, very careful.

There are some good signs though. I recently heard of two young Mig-29 and Jaguar pilots wanted to fly the LCA instead.

[Cain Marko]

- With empty weight believed to be within 10% range of Mk-1, the T/w ratio would make MiG-29 blush in A-A role.

That's not happening. With all the stuff that they plan to add to the mk2, weight will be a lot more. And the f414 will not produce enough thrust to bring the mk2 close to a fulcrum.

Not that the bird won't be potent, but no it's not going to compare to most present era twin engined fighters in terms of power. It is precisely the reason the Navy quit on the nlca.

We'll be looking at another mirage 2000, which is great but it's not exactly renowned for it's power.

I'm very sceptical about this need for more payload for the tactical role it will have, and also the reasonableness of that need for a fighter of this class.

I remember reading a comment from ADA that increase in combat radius will be about 20 pct.

The t/w ratio is the only improvement that seems worthwhile. But I say that without knowledge of specifics so I may well be wrong

.

Akshay sir, i believe you are in the right track. if you are looking for a great tactical short range type fighter the mk1a will be more than enough. The mk2 might not hold any great advantage in a small confined role. For widert roles the AMCA is a much better investment. And frankly, I think ADA and all the other stakeholders realize this and hence the mk2 has been somewhat kept on the back burner.

Jmvho despite it going against the BR grain.

[Karan M]

If we can make a Mk2 with more fuel than the Mk1A why shouldn't ADA jump at the chance? The suggestions Indranil points to are all eminently feasible. Next, about weight gain - apart from more fuel and a few hundred kilos for the SPJ, where will Mk2 gain more weight?

That's not happening. With all the stuff that they plan to add to the mk2, weight will be a lot more. And the f414 will not produce enough thrust to bring the mk2 close to a fulcrum.

Present MK1 is around 1.3T more than plan because of overengineering eg undercarriage etc. Some of that weight shaved off in Mk1A will be traded off for the AESA radar. Mk2 adds significantly more thrust for the same overall weight and marginally larger dimensions.

[Cain Marko]

^among other things I expect weight gain over the mk1 to come from...
Additional 1 mtr plug, obogs, aesa, internal ew, strengthening of wings and structures for additional payload etc.

I'm not talking about feasibility, it is eminently feasible to make a mirage 2000ish bird. But it will take time and resources, I'd rather them jump on the AMCA instead. I feel that weight loss to the extent that it will be comparable to a twin engined mrca type fighter is a fantasy. A look at the bloat on the gripen suggests that as well.

[Philip]

Saik, during the last decade the MK-2 prototype should've been built so that we were in the testing phase and production begin in early 2020+. The DRDO/ADA, MOD have little concept of time, obsolescence in the global sense.When US aircraft start flying with laser weaponry in the next decade they might wake up.

But the key for the future is the munitions that any fighter can carry."Performance centric rather platform centric".If the LCA can carry Astra, etc. , which a Rafale carries too, our a similar stand-off weapon, then wouldn't the less expensive LCA be more attractive?

[Karan M]

^among other things I expect weight gain over the mk1 to come from...
Additional 1 mtr plug, obogs, aesa, internal ew, strengthening of wings and structures for additional payload etc.

I'm not talking about feasibility, it is eminently feasible to make a mirage 2000ish bird. But it will take time and resources, I'd rather them jump on the AMCA instead. I feel that weight loss to the extent that it will be comparable to a twin engined mrca type fighter is a fantasy. A look at the bloat on the gripen suggests that as well.

It was not 1 mtr but half a meter.
http://www.bharat-rakshak.com/media/421 ... as-mk2.jpg

Also, the AESA is already offset with weight reductions over Mk1, ditto for internal EW. The weight gain via strengthening of wings and structures sounds very speculative at this point - haven't ready anywhere they planned to do that. In fact, the reverse was planned.



The Tejas Mk2 offers us a SEF equivalent while the uber AMCA whatever comes about, we should just take it.

The Gripen EF, Rafale, etc are all selling and not being removed merely because they are 4.5 Gen.

[Karan M]

Saik, during the last decade the MK-2 prototype should've been built so that we were in the testing phase and production begin in early 2020+. The DRDO/ADA, MOD have little concept of time, obsolescence in the global sense.

Please provide the funding for all these trivial activities.

When US aircraft start flying with laser weaponry in the next decade they might wake up.

The IAF should just stop flying because.. lasers.

[JayS]

I'm very sceptical about this need for more payload for the tactical role it will have, and also the reasonableness of that need for a fighter of this class.

I remember reading a comment from ADA that increase in combat radius will be about 20 pct.

The t/w ratio is the only improvement that seems worthwhile. But I say that without knowledge of specifics so I may well be wrong.

And I doubt very much that all three of the above can be achieved simultaneously. If you go for payload then you negate the thrust/w increase for example.

Would love to hear the views of the experts. With specific number on the key parameters of poss. If these questions have already been addressed then my apologies.

I'll put it this way - we can make LCA MK2 which is equivalent to Gripen NG in every respect. If IAF is happy with 114 of Gripen NG, IAF would be happy with 114 Mk2. If Mk1A was enough for IAF, they wouldn't have asked for SEF. If we have a chance to give IAF what they want, why not..?

What was the fuel capacity hike that was expected for LCA Mk2..? 700kg comes to my mind. Thats ~1hr increase in Endurance or 700-800km increase in Range at economical cruise at altitude for A2A config. Very significant numbers, if you ask me. On top of it all the refinements in aerodynamics, fully upgraded FCS, Avionics, Internal SPJ, higher thrust, increased payload (means increased External fuel capacity too for CAP/BFS missions where endurance matters).

[JayS]

^among other things I expect weight gain over the mk1 to come from...
Additional 1 mtr plug, obogs, aesa, internal ew, strengthening of wings and structures for additional payload etc.

I'm not talking about feasibility, it is eminently feasible to make a mirage 2000ish bird. But it will take time and resources, I'd rather them jump on the AMCA instead. I feel that weight loss to the extent that it will be comparable to a twin engined mrca type fighter is a fantasy. A look at the bloat on the gripen suggests that as well.

was going to post image of ADA brochure for MK2 from 2015. I see Karan beat me to that.

One of the stated upgrades is - Structural weight reduction.

Now consider some weight reduction on account of optimised airframe (I hope they bring in Co-bonded Co-cured tech in airframe. We have the tech already, that would shave off quite a bit of weight all over). And then add weight of all those things you listed above. Overall addition of weight should not be more than 500-600kg. Even if its as much as the increase in thrust i.e. ~17% ~ 1.1T, still due to various refinements in aerodynamics, MK2 will still have significantly better kinematic performance than Mk1/1A. But there are good chances that the weight hike would be moderate only.

Whether that would beat MiG29, I don't know though.

[Akshay Kapoor]

Fair points JayS. In the SEF Gripen contex that certainly makes sense. But I also happen to hold the view that SEF and especially Gripen won’t go through. I also think that MK1B as per Indranil terminology (all possible improvements without new engine) will certainly happen. It will happen as a new batch of orders. Wait and see.

Thanks for the detailed answer Indranil. Much appreciated.

Jay Are you sure of the 700-800 km number ? We must request ask Vivek Ahuja to do another simulation to cater for the MK2 engine.

Thanks all for the answers.

[Karan M]

The LCA Mk2 weight is intended to be 6560 Kg. Current LCA Mk1 weight (around LSP-8) was around 6700 Kg.
In short, the LCA Mk2 adds significantly more thrust for the same weight.
https://thefearlessindian.in/wp-content ... -mk2-1.jpg

Next, there is no plan to increase payload - it remains at 3500 kg. So Cain, this belief that extra strengthening will be needed for extra payload is speculative.

[Karan M]

Also Mk1A will introduce many of the improvements intended for Mk2. So the speed of introduction of Mk2 should be reduced with many systems directly ported over from Mk1A.

[JayS]

Fair points JayS. In the SEF Gripen contex that certainly makes sense. But I also happen to hold the view that SEF and especially Gripen won’t go through. I also think that MK1B as per Indranil terminology (all possible improvements without new engine) will certainly happen. It will happen as a new batch of orders. Wait and see.

Thanks for the detailed answer Indranil. Much appreciated.

Jay Are you sure of the 700-800 km number ? We must request ask Vivek Ahuja to do another simulation to cater for the MK2 engine.

Thanks all for the answers.

Point is IAF does want that kind of fighter. There is a requirement (part of MMRCA). And we can tailor make MK2 for that. As Karan said Mk2 offers us equivalent of SEF, so eliminate SEF by fulfilling the requirement by MK2.

They are approximate estimations. I can do some simple hand calculations to justify (should give ~40-50min of endurance with crude formulae). But I have seen a data point for F404 wrt to F/A-18 - Economical cruise at 41000ft at M0.85 needs 1600lb/hr fuel per engine. That was for F404 engine from 1980s. By now there are some improvements in sfc of F404 itself and F414 was suppose to have 3-4% sec improvement over F404. With that we can assume that current F414 could make LCA MK2 cruise at similar altitude and M number with similar fuel consumption. Considering little more since LCA is single engine, but then reducing some on account of improved sfc. All in all with 1600lb = ~720kg fuel, ~1hr of endurance or range of 700-800km at ~0.8-0.85M.

[Thakur_B]

^^ The 3500 Kg is supposed to be reasonable payload. The hard point capacity of mk1 is in excess of 5 tons. I expect tejas mtow to be within 1 ton of Gripen ng.

[Zynda]

I hope ADA goes for rigorous weight optimization of the airframe on Mk.2 but still I think we will see north of 7000 Kg for Mk.2.

[JayS]

I hope ADA goes for rigorous weight optimization of the airframe on Mk.2 but still I think we will see north of 7000 Kg for Mk.2.

I agree. I would bet on 7.3T if I have to choose one number.

[Akshay Kapoor]

Fair points JayS. In the SEF Gripen contex that certainly makes sense. But I also happen to hold the view that SEF and especially Gripen won’t go through. I also think that MK1B as per Indranil terminology (all possible improvements without new engine) will certainly happen. It will happen as a new batch of orders. Wait and see.

Thanks for the detailed answer Indranil. Much appreciated.

Jay Are you sure of the 700-800 km number ? We must request ask Vivek Ahuja to do another simulation to cater for the MK2 engine.

Thanks all for the answers.

Point is IAF does want that kind of fighter. There is a requirement (part of MMRCA). And we can tailor make MK2 for that. As Karan said Mk2 offers us equivalent of SEF, so eliminate SEF by fulfilling the requirement by MK2.

They are approximate estimations. I can do some simple hand calculations to justify (should give ~40-50min of endurance with crude formulae). But I have seen a data point for F404 wrt to F/A-18 - Economical cruise at 41000ft at M0.85 needs 1600lb/hr fuel per engine. That was for F404 engine from 1980s. By now there are some improvements in sfc of F404 itself and F414 was suppose to have 3-4% sec improvement over F404. With that we can assume that current F414 could make LCA MK2 cruise at similar altitude and M number with similar fuel consumption. Considering little more since LCA is single engine, but then reducing some on account of improved sfc. All in all with 1600lb = ~720kg fuel, ~1hr of endurance or range of 700-800km at ~0.8-0.85M.

Thanks for this JayS. Do feel free to refine with more calculations

I see the logic for MK2 as part of SEF evaluation.

[Cain Marko]

The LCA Mk2 weight is intended to be 6560 Kg. Current LCA Mk1 weight (around LSP-8) was around 6700 Kg.
In short, the LCA Mk2 adds significantly more thrust for the same weight.
https://thefearlessindian.in/wp-content ... -mk2-1.jpg

Next, there is no plan to increase payload - it remains at 3500 kg. So Cain, this belief that extra strengthening will be needed for extra payload is speculative.

It might very well be speculative but I have never seen a fighter payload and size increased without a consequent increase in weight. The examples are legion...f16, f18, f15, mig35, su30, and now the gripen ng.

What is being promised by the ADA seems a little too fantastic... One look at the gripen and we realize that it is not so easy.

Having said this, there is always the possibility that the older airframe was not optimized and refined and so the newer bird might not see a very great increase in weight. The closest to this is the evolution of the mig29 into the mig29m, even so there was still a slight increase in weight.

My guess is that the mk2 will weigh in upwards of the 7 ton mark. And come very close to the Uber airframe if the mirage 2000 ~ 7.5 tons. And that is no mean achievement..

However, I don't see value in this. IAF has a need still of low end fighters in large numbers and the mk1a is eminently suitable for this role. Frankly even the mk1 foc standard is. Another 126 should be ordered. These can be kept up to date with appropriate upgrades. In the meanwhile, ADA should concentrate it's energies on the AMCA. once that bird is ready, they can move on to the next low-end fighter more suitable for the 2050-60s.

It goes without saying of course, nevertheless I will say it, that the SEF program has no room in my designs.

[YashG]

.When US aircraft start flying with laser weaponry in the next decade they might wake up.

Air warfare may not see laser for a long time to come. Because lasers will never be BVR. In the end laser is just light - just more powerful but its physics will still be like light. You can only zap as far as you can see.

If standoff BVR A2As keep getting leggy and better, they will always be the go to weapons for AFs. an Astra would always better a laser that ways.

[Indranil]

The empty weight of Mk2 will not be much more than that of the Mk1. Let us see the things that are going to add weight:

1. A 0.5 mtr fuselage will not weigh more than 300 kgs more in metal and plastic (If the 700 ltr tank number is true, then it has a >700cc hole in it).
2. Internal EW about 150 kgs (guesswork).

Let us see things where they will save weight:
1. Lighter radar
2. Structural optimizations (Mk1 to Mk1A)
3. OBOGs instead of LOX cylinders

So expect empty weight of LCA Mk2 to be around 500 kgs more than the Mk1A and 100-200 kgs more than the Mk1. I would guess that it will be in the 7000 kg range.

OCC (Clean TO weight) of the Mk2 will likely be 600-700 kgs more than the Mk1 and about 1000 kgs more than the Mk1A. Mk1:9800 kgs, Mk1A: 9500 kgs, Mk2: 10500 kgs.

MTOW of Mk1/Mk1A: ~14 tons Mk2: ~15tons.

[Indranil]

This picture from two years back show four optimizations:
1. Canopy reshaping
2. Actuator fairing extensions
3. Intake cowling reshaping
4. More streamlined midboard pylon

[ramana]

JayS and Indranil

Can you both rank the changes in weight from MK1A to MK2 wrt range

[Vivek K]

The LCA has been funded for 3 decades+.When it was found that weight was an issue and a MK-2 was needed which the IAF was gung-ho about, saying it would meet all its requirements, a swift decision to start building the MK-2 prototype with the F-414 engine should've started.Funding? We've been funding the programme for over 3 decades. Surely the cost of a few MK-2 prototypes could've been worked into the overall R&D costs. How come the " Cinderella of the services" the IN coild find the money for their share of the programme.

If all the stakeholders had jointly pressed the GOI/ MOD, it would've happened.At that time the MMRCA show was hogging the limelight.Perhaps the anticipation of 120 of the same was more attractive than a Desi MK-2..How many voices were rooting for the MK-2 at that time too?

Still not too late .Look how long the F-16 and MIG-21 programmes have lasted with umpteen upgrades and variants.When compared with Rafale costs, a few MK-2 prototypes should be assured to HAL.
But as said before delays will kill it.Chin stealth fighters and US future fighters with bells and lasers will bury a simple MK-2.The IAF will demand more sophisticated fighters.
.

All deliberate misrepresentations by now typical of this poster. The MK-1 was never under powered till the NLCA was designed. IN was looking at a MK-2 development which caught IAF’s attention. With weapon and fuel load outs (plus IFR) in current configuration the LCA can reach Alaska. The IAF has still not gotten behind the MK-2 so all this is B.S. To expect that HAL would on its own initiative fund a MK-2 prototype is delusional to put it mildly. Nowhere in the world does a company work on a design without a funded fighter competition! But then of course if the motivation is to kill local for foreign masters, then this drivel can be understood!

[Cain Marko]

The empty weight of Mk2 will not be much more than that of the Mk1. Let us see the things that are going to add weight:

1. A 0.5 mtr fuselage will not weigh more than 300 kgs more in metal and plastic (If the 700 ltr tank number is true, then it has a >700cc hole in it).
2. Internal EW about 150 kgs (guesswork).

Let us see things where they will save weight:
1. Lighter radar
2. Structural optimizations (Mk1 to Mk1A)
3. OBOGs instead of LOX cylinders

So expect empty weight of LCA Mk2 to be around 500 kgs more than the Mk1A and 100-200 kgs more than the Mk1. I would guess that it will be in the 7000 kg range.

OCC (Clean TO weight) of the Mk2 will likely be 600-700 kgs more than the Mk1 and about 1000 kgs more than the Mk1A. Mk1:9800 kgs, Mk1A: 9500 kgs, Mk2: 10500 kgs.

MTOW of Mk1/Mk1A: ~14 tons Mk2: ~15tons.

I hope you are right but I'm a wee skeptical...
Iirc the Honeywell obogs solution doesn't show weight gain as one of the benefits of obogs over lox. An opportunity I'm sure they wouldn't have missed in their slick brochure.
How well an aesa radar with it's heavier antenna and cooling requirement be lighter than the 2032?

7500kg will be a great achievement and within the reason of possibility I guess.

[Cain Marko]

[The MK-1 was never under powered till the NLCA was designed. IN was looking at a MK-2 development which caught IAF’s attention.!

So if IAF didn't need more thrust, which was supposedly the main drawback of the mk1, why are folks now clamoring for the mk2 for IAF¿

[srin]

The empty weight of Mk2 will not be much more than that of the Mk1. Let us see the things that are going to add weight:

1. A 0.5 mtr fuselage will not weigh more than 300 kgs more in metal and plastic (If the 700 ltr tank number is true, then it has a >700cc hole in it).
2. Internal EW about 150 kgs (guesswork).

A couple of other things:
3. GE 414 is around 75-100 kg more than GE404
4. The SFC of GE414 is greater than that of GE404. So to travel the same distance, more fuel needs to be carried, rt ? Don't know enough math to say approximately how much though.

[Vivek K]

[The MK-1 was never under powered till the NLCA was designed. IN was looking at a MK-2 development which caught IAF’s attention.!

So if IAF didn't need more thrust, which was supposedly the main drawback of the mk1, why are folks now clamoring for the mk2 for IAF¿

Because the IAF is looking for an MRCA. The belief is that the enhancements of the MK-2 would add capabilities that would cover the MRCA configuration.

It is amazing that the LCA was declared overweight without allowing for the obvious weight shedding - instrumentation, plug etc. IR has posted details please lookup.

[shiv]

I'm very sceptical about this need for more payload for the tactical role it will have, and also the reasonableness of that need for a fighter of this class.

I remember reading a comment from ADA that increase in combat radius will be about 20 pct.

The t/w ratio is the only improvement that seems worthwhile. But I say that without knowledge of specifics so I may well be wrong.

And I doubt very much that all three of the above can be achieved simultaneously. If you go for payload then you negate the thrust/w increase for example.

Would love to hear the views of the experts. With specific number on the key parameters of poss. If these questions have already been addressed then my apologies.

Exactly the same issues came up with the MiG 21 as noted by Air Marshal Rajkumar in his chapter in the MiG 21 50 years commemorative book. He says that the original Type 77 was lightly armed, short ranged and a real joy to fly - a pilot's dream. Decades later the MiG 21bis had a very powerful engine but had gained so much weight that its performance barely reached that of the Type 77. But he says the bis is a much more capable and useful aircraft, though the 77 gets marks for "joy of flying"

So I suspect that a heavier and more powerful Tejas will have more useful avionics, weapons and capabilities, and perhaps some increased range.

[Indranil]

The empty weight of Mk2 will not be much more than that of the Mk1. Let us see the things that are going to add weight:

1. A 0.5 mtr fuselage will not weigh more than 300 kgs more in metal and plastic (If the 700 ltr tank number is true, then it has a >700cc hole in it).
2. Internal EW about 150 kgs (guesswork).

A couple of other things:
3. GE 414 is around 75-100 kg more than GE404
4. The SFC of GE414 is greater than that of GE404. So to travel the same distance, more fuel needs to be carried, rt ? Don't know enough math to say approximately how much though.

3. Is correct
4. Don't know about the exact SFC of cruise for F404 and F414. For example, the Super Hornets get 3-4% better fuel efficiency than the Hornets for cruise settings.

[Trikaal]

Let us see things where they will save weight:
1. Lighter radar.

Are u sure about this? Afaik aesa weighs more than the pesa that tejas currently has. I will quote the figures if i find them. From what i remember and from wiki,
Current radar weight- 100kg
Proposed aesa weight- 250kg
The 150 kg excess was supposed to be mitigated by removing some ballast in nose cone but thats another matter.

[Indranil]

Yes.