LCA Tejas: News and Discussions

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Re: LCA Tejas: News and Discussions

Postby Aditya_V » 09 Mar 2015 11:42

vaibhav_kumar wrote:Saw this on idrw.org. Not sure what sense to make of it. The data in this shows that our LCA is no match even for the bandar :cry:
What does the Gurus' analysis say?

http://idrw.org/archives/59478


I suggest there is no need to share that link, obviously a hit job.

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Re: LCA Tejas: News and Discussions

Postby karan_mc » 09 Mar 2015 12:59

vaibhav_kumar wrote:Saw this on idrw.org. Not sure what sense to make of it. The data in this shows that our LCA is no match even for the bandar :cry:
What does the Gurus' analysis say?

http://idrw.org/archives/59478


Prof. Prodyut Das / Former Professor Mechanical Engineering IIT Kanpur

Author has been strong LCA hater for ages now , Nothing new in his report .

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Re: LCA Tejas: News and Discussions

Postby Indranil » 09 Mar 2015 19:32

No. He is not a LCA hater. His has a very alternate view of how things should or could have been run. As for this article, I feel he oversimplified many things. But that is my opinion.

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Re: LCA Tejas: News and Discussions

Postby shaun » 10 Mar 2015 07:41

^^^^
the opening paragraph starts with flawed statement because Yehlanka is a transport hub and sulur is not too far from bangalore . we know some of the reasons for delay in achieving FOC is due to chobham . And although i am not expert on this matter , the only thing i can say is , the whole article was written on assumption based on a data table , how he arrived on that figures , he could have provided some link as his source is all "open source" . And it is an old article , how and why IRDW published it now ??

I think this guy is some what similar to uncles you will typically find in gatherings and parties ,where this self proclaimed expert on "everything" convince people with out of the world things a.k.a PSG :-o

Although i did it , it will be better not to give much air to the wings of this self proclaimed baba ,
http://profprodyutdas.blogspot.in/2014/12/the-ada-lca-2014-open-source-review.html
read the comment sections.

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Re: LCA Tejas: News and Discussions

Postby Indranil » 10 Mar 2015 08:53

Can you argue against his points? You know he knows his aerodynamics quite well.

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Re: LCA Tejas: News and Discussions

Postby rohitvats » 10 Mar 2015 09:34

indranilroy wrote:Can you argue against his points? You know he knows his aerodynamics quite well.


indranilroy - I think it would be good idea to address points raised by the professor either ways. This can serve a technical fact sheet about the fighter and we know where we stand with respect to these and some other issues. Some hawa-bahadurs of BRF will have to raise their hand for this exercise.

Also - we can invite the professor on BRF and have a thread where we discuss issues raised by him. Will become a dialogue and he can answer queries. But this will need to be moderated to ensure the quality of discussion.

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Re: LCA Tejas: News and Discussions

Postby Indranil » 10 Mar 2015 10:06

Something really holding me back till April 6.

1. I would like to critique his last article. I read this article on his blog about two months back ;-). There is no problem with the aerodynamics part of it. But he does make quite a few oversights. For example, calling LCA a delta wing which has reached the end of evolution is quite an oversimplification.
2. He is a very hands-on aerodynamist, the purist kind. People who would add wood to a fighter and fly it to get a feel, then sand it, and fly again. Actually, most theories in aerodynamics did come from people of that era who just did it, rather than write proposals. So I would love to invite him here, and have a thread where he suggests stuff, hawabaaj's question him, and there is fire. It will certainly be better than many threads currently.

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Re: LCA Tejas: News and Discussions

Postby jamwal » 10 Mar 2015 10:06

He is also the sort of expert who advocated that India should raise an air force of 1000s of cheap, low tech Marut type of fighters instead of investing in quality. While his theoretical aeronautics could be correct, his ramblings and what should be done is downright idiotic.

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Re: LCA Tejas: News and Discussions

Postby Akshay Kapoor » 10 Mar 2015 11:33

I agree Indranil and Rohit. I would very much welcome an informed discussion on BR but you will have to moderate it very closely to keep the hawabaaj's that we have more than our fair share of out. I have written to him asking for a few clarifications.

If his aerodynamics are correct and we know the engine's dry thrust and relight thrust then what are the key flight parameters ? Indranil, I still think ITR is good but I doubt that STR will be around 17/18 as we had briefly discussed a few months ago. I think it will be useful for us to do a detailed comparison with Bison in terms of flight regimes. Lets leave avionics out.

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Re: LCA Tejas: News and Discussions

Postby Indranil » 10 Mar 2015 12:24

Bear with me till the 6th of April.

There is really no way to calculate the STR without knowing the LoD curve. And there is no way to calculate the LoD curve without wind tunnel or CFD data. It is really non-linear in that domain. But, even if I take it that it is more draggy than the Mirage, it has better wing-loading and TWR. So, I can't see how it can be much worse in STR.

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Re: LCA Tejas: News and Discussions

Postby ArmenT » 10 Mar 2015 12:38

Not directly LCA related, but this is a very interesting film by Shell Oil produced many years ago, explaining transonic and supersonic flight issues in layman's language. Mods: if this isn't the correct thread, please move appropriately.

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Re: LCA Tejas: News and Discussions

Postby Singha » 10 Mar 2015 13:33

Dr Das is obviously a formidable mind and difficult customer after reading his blog. he may be wrong, but he is highly convincing and imperious in his reasoning.

Kind of like N3 and Philip sir and vivek ahuja all rolled into one fighting unit.

you guys had better plan your questions properly if you want to engage.

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Re: LCA Tejas: News and Discussions

Postby Indranil » 10 Mar 2015 14:23

I have followed him for some time now and was pleasantly surprised to see my name pop up in one of his blog entries. I have discussed things with him in the past, and it was an enjoyable experience, even when we disagreed. He is certainly way more knowledgeable than me, and with a lot of domain expertise. He is also opinionated on how we should go about developing our wares and human resources.

And this is where he disagrees with the LCA program and its outcome. To me, its a knowledgeable opinion. And there are many gyanis who agree with him. At the same time, people in ADA are excellent as well. The only thing is that they can't voice their opinions in public. So, we have to make educated guesses based on the design choices they made. As for internet ninjas, I have learnt not to pay too much attention to most of them.

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Re: LCA Tejas: News and Discussions

Postby shaun » 10 Mar 2015 21:14

^^^
its a very good idea to invite him in this forum but i am skeptical of the good prof ,showing up. His main contention or rant is ,tejas is overweight by a big margin and so can never fulfill its design parameters. He is even accusing ADA of telling lies as according to him ,this over weight tejas is supersonic only in dives .!! another marut in the making !!

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Re: LCA Tejas: News and Discussions

Postby Jayram » 10 Mar 2015 21:52

seems the good prof is being raked over the coals.. See comments on his blog

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Re: LCA Tejas: News and Discussions

Postby rohitvats » 10 Mar 2015 22:31

Jayram wrote:seems the good prof is being raked over the coals.. See comments on his blog


With all due respect, the 'comments' are more of 'he said and she said' kind of nonsense. They do not answer the points that Professor has raised. Funny thing is, Tejas can well be all that the spirited 'guest' is arguing (save for the aerodynamics parts) and Professor's point would still hold. There is one comment by someone claiming to be a ex-fighter pilot where he argues about Tejas requiring more dry thrust.

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Re: LCA Tejas: News and Discussions

Postby rohitvats » 10 Mar 2015 22:40

I think with respect to Tejas Mk1, the following points should be subject of the debate:

1. Aerodynamics related aspects and issues. Where does LCA stand on these aspects. This should also help to understand the issue(s) raised by IAF with respect to Tejas Mk1.

2. Technological aspects - Now, when the professor talks about Tejas Mk1 being only X% better than Mig-21 Bis, it is only from aerodynamic POV. But today's fighter is much more than that. The technology comes into play very prominently and has huge impact on performance. So, the overall technological aspects which Tejas brings into play.

3. How the technology in above point helps to address issue(s), if any, with respect to Point 1.

I think a focused discussion on above points will help us to address the main questions being raised around the Tejas Mk1 platform. It will also help to understand level of improvement asked for in Tejas Mk2.

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Re: LCA Tejas: News and Discussions

Postby shaun » 10 Mar 2015 22:43

This is what the 'someone claiming to be a ex-fighter pilot " have to say
"Professor, Your calculation regarding T/W for most aircraft are grossly wrong. you have calculated LCA on the lower side and other aircraft on the higher side. I suggest that you pls re-check your data and calculations. LCA with 6500kgs as empty weight and 9000 kgs as loaded weight has a T/W of 0.6(dry) and 1.0 (A/B). Though I do agree to just few of your points but most are bullshit to say it politely. I am a retd fighter pilot myself and very well understand what you have written here. If calculate wrong, you will arrive at wrong calculations. I do agree to your point that LCA wing shud have been reversed i.e it shud have more sweep in front and less sweep at rear and that engine shud have a bit more dry thrust. LCA does not need more of A/B thrust, it needs more of dry thrust.
ADA has again gone wrong by selecting F414 engine which will give adry thrust of just 62.5KN. EJ-230 wud have done wonders to LCA with its dry thrust of 72KN."

That's the reason , i was asking for the open source specification links he have considered for his calculations. Anyway , good luck if you can pursue him in this forum.

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Re: LCA Tejas: News and Discussions

Postby Indranil » 10 Mar 2015 23:07

Shaun wrote:^^^
its a very good idea to invite him in this forum but i am skeptical of the good prof ,showing up. His main contention or rant is ,tejas is overweight by a big margin and so can never fulfill its design parameters. He is even accusing ADA of telling lies as according to him ,this over weight tejas is supersonic only in dives .!! another marut in the making !!

Yes, he had made that accusation before on Ajai Shukla's blog. Ajai Shukla said he would rather believe the test pilots :-)

On the other hand his prime tormentor on the current blog is Mr. Sakthivel ( very active member of another forum). He has followed LCA Tejas very closely and a firm believer in the project. But he does make facepalm comments too. For example sample this.
All the so called drag for not following Whitcomb's rule more rigidly comes into play only in super sonic flight regime, not in subsonic flight regime of WVR combat speeds.

So no drag issues here also.

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Re: LCA Tejas: News and Discussions

Postby shaun » 11 Mar 2015 00:29

Indranil Sir , honestly speaking , like you said without the CFD or wind tunnel data , we ( actually its not we but resident experts like you ) can't come to any conclusion on the aerodynamic issues .

Gripens published datas are now blocked, even the data on trials carried out by a certain air force is also not available now.

My contention is , some people with vested interest will use his article ( which is flawed in some sense ) as browne points against LCA. And yes we jingos will try our level best to hit back on anything showing LCA in poor lights at this juncture of LCA's development when one squadron is already coming up . Let IAF play with it , its designs advantages and drawbacks will shop up in due time.

The same prof. had also given suggestions on IJT , maybe we can look back to what he have said and compare with it , the design changes considered by HAL.

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Re: LCA Tejas: News and Discussions

Postby Indranil » 11 Mar 2015 01:29

No sir for me please.

Actually, he loves the original IJT team, and is a big supporter of the IJT and HTT-40 projects. Also, based on the remedial actions that we have heard of in public domain, the problems that he suggested may very well be true. We will have to wait and watch.

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Re: LCA Tejas: News and Discussions

Postby shiv » 11 Mar 2015 06:40

Much as I admire Prof Prodyut Das' bold lateral thinking ability - he sure is having several new ones ripped open for him by ersaktivel of DFI and even one former fighter pilot. :D
http://profprodyutdas.blogspot.in/2014/ ... mment-form

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Re: LCA Tejas: News and Discussions

Postby JTull » 11 Mar 2015 07:00

Bottomline is that there is no such thing as a perfect aircraft. And it is much easier to find faults in someone else's efforts than make an effort yourself. Without participating such efforts but having the knowledge to offer informed opinions is still being an armchair general like any jingo here, no better or worse. Having an agenda in calling everyone else a non-believer only makes him a fanatic, not a learned professional.

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Re: LCA Tejas: News and Discussions

Postby maitya » 11 Mar 2015 09:08

shiv wrote:Much as I admire Prof Prodyut Das' bold lateral thinking ability - he sure is having several new ones ripped open for him by ersaktivel of DFI and even one former fighter pilot. :D
http://profprodyutdas.blogspot.in/2014/ ... mment-form

Not jump-in in the fine discussion wrt the good prof's blog etc, but a simple mango-punch keeps bothering me:
(frankly, not only in this case, but whenever I see such attempts to compare, most of time based on brochurities, an aircraft operating in indian condition and those that doesn't)

1. How many of these said "aircrafts" will be able to take-off from, say Leh, with say 3 drop tanks and 2 CCMs hanging on it's pylons?
(notwithstanding of course many of the ones mentioned by the good prof wouldn't have that many pylons and even if they have, will struggle to take-off, with taht kind of load, from sada Dilli etc.).
And of course, the related question would be, if they are able to take-off what was the roll-off distance they will require to do so?

Any shiny-brochure that would help me get an answer to this basic puch.
Last time I heard, the big-fancy-TFTA (with technicolour brochures to boot) ones really really struggled to do so, couple of years back (as a part of MMRCA eval).


2. Sorry couldn't resist - another one, how many of these said aircraft would be able to achieve Mach 1 at "sea-level" with the similar loading mentioned above.
LCA just fell short of it, so would be a good chance to run it down and belittle it, again.

Of course, the answer can be pure hand-waiving one like, why does IAF need to have aircraft taking off from Leh, nothing grows there so where is the need to defend these mountainous area (in the rhyme of the utterings of the fine Mantris and Netas of 50s-60s, befitting to the era of this good-prof's "thinkings and utterings" :evil: ).

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Re: LCA Tejas: News and Discussions

Postby member_28640 » 11 Mar 2015 10:34

shiv wrote:Much as I admire Prof Prodyut Das' bold lateral thinking ability - he sure is having several new ones ripped open for him by ersaktivel of DFI and even one former fighter pilot. :D
http://profprodyutdas.blogspot.in/2014/ ... mment-form

Saar the retd fighter pilot is a Navy pilot who has very considerable experience in landing harriers on the viraat, he is very knowledagble regarding aerodynamics of fighter jets..
He is also very active in a forum that you very much hate ( Hint : Its not a pk forum)

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Re: LCA Tejas: News and Discussions

Postby uddu » 11 Mar 2015 10:46

The professor can go wrong. Not a big deal. We have the most prominent U.S aircraft manufacture with decades of experience in designing and building the best fighter aircraft telling the then Defence minister of India George Fernandes that Tejas will not take off and will crash prior to the first flight. So the professors assessment correct or wrong is nothing compared to that. :lol:

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Re: LCA Tejas: News and Discussions

Postby astal » 11 Mar 2015 11:44

I have little knowledge of aerodynamics but this article by Prof. Produt Das seems superficial and flies in the face of many observations that have nothing to do with aerodynamics.

What Prof. Das would like to see is a simple LCA bomb truck. Something like what the IAF wanted a long time ago. A poster named Abhibhushan (it appeared that he was ex IAF ), in an excellent post a few years ago, described his ideal two engined bomb truck, without any fancy new technologies. This would be close to Prof. Das's vision except for the single engine.

Such an aircraft, if designed 25 years ago and inducted 15 years ago would have served IAF well, it would be an indigenous upgrade to the Jaguar and offer an evolution path to an Indian MRCA. The Indian MRCA would have all the bells and whistles of a modern 4th generation aircraft including Delta wing with canard or wing sweep, AESA BVR radar, Quad digital FBW. The only problem would be to find a suitable engine or pair. Good engines were not available to us at the time and those available were underpowered, difficult to maintain or consumed too much fuel.

Fast forward 25 years and every 4 and 4+ generation aircraft has a delta wing configuration, rejected by Prof. Das. All the Eurocanards which the IAF covets are delta winged aircraft. Even without understanding aerodynamics, the question arises: Why are the all 4+ gen fighters delta winged if this is a step backwards.

The second thing that is difficult to understand is Prof. Das's dismissal of BVR capabilities. One explanation could be that Prof. Das only understands aerodynamics and is at sea with electronics and Radar. Not trusting BVR does not make its lethality go away. Every contemporary aircraft has a lot of emphasis on BVR, radar and tactics. Either every aircraft manufacturer and Air Force that drew these requirements are wrong or Prof. Das is clueless about many aspects of modern fighter design. I am guessing the latter.

The third thing that makes no sense is his criticism of composites. I have no explanation for this. This is another issue where every aircraft is moving to composites as they are light weight and durable. What could be wrong with that?

That being said, from a strategic and tactical perspective, I would really wish for the LCA MK2 to be focused for ground attack. With a little more fuel, some weight optimization and wing/fuselage tweaks(if needed), they could eliminate the need for MRCA and double the production of the LCA. I feel IAF already have one of the best 4th gen fighter aircrafts ever made in the form of the Su 30 MKI. We need decent 4th gen mud movers.

Another track would be to simultaneously work on a new version, the LCA MK3 that would be optimized for Air Combat. With minor changes for a modicum of stealth and the best possible ITR and acceleration aerodynamics, this fighter would fill in numbers for point defense and CAP.

The LCA suffers a bit from trying to be multirole, a good fighter and a good bomb truck. Trying to cram all these capabilities in a small, light frame has resulted in the compromises that the LCA must live with today. But looking at its performance, I would say it has come a long way and is ready, even in its present for, to serve many useful roles in the IAF and it can only get better. Prof. Das has his day in the sun. His opinions are stuck in the 80s and the world has moved on.

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Re: LCA Tejas: News and Discussions

Postby astal » 11 Mar 2015 12:12

Sorry. After writing that longish post, I went back and re-read Prof. Das's post. The one thing that he stressed is that 'pure delta' is a dead end. I know that LCA is a cranked delta but I am not sure what wing design he is suggesting? It would be interesting to evaluate alternate wings designs that could quickly fix whatever acceleration and turn rate problem LCA suffers from. Perhaps the Naval MKI has done precisely that.

As for the other two points, dismissal of BVR and composites. I think Prof. Das underestimates the need for these technologies.

But looking at the conclusions, he suggests that we build up a manufacturing capability of 60 aircraft per year for LCA MK1 in its present form by 2017 and sort out manufacturing issues. My jingo heart cannot disagree with that. I know that the LCA is much better than the JF-17, Mig 21, Jaguars and Gnat for the roles that IAF needs urgently regardless of the brochure numbers thrown about in the article. For Air superiority IAF has SU 30 MkIs.

A ground attack optimized LCA with a F414 engine, more fuel, better wings and weight optimization can come around 2020 to 2025. Now who will convince the IAF?

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Re: LCA Tejas: News and Discussions

Postby member_28640 » 11 Mar 2015 12:25

Saar you are right in thinking that he wants a bomb truck which is why I feel that he has a problem with composites...
Strike and CAS roles would put it in the reach of small arms fire.. While that may cause just a dent or a hole in a metal craft which can be easily repaired in little time, in a composite panel that would mean replacing the whole panel as the fiber would have lost its tension.
This could create a logistical nightmare in FOB, I guess that this is what the Professor thought.

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Re: LCA Tejas: News and Discussions

Postby Singha » 11 Mar 2015 13:02

in the other deltas like Gripen, the sweep angle near the fuselage is more than outer part. in Tejas it is uniquely reversed.
even the avro vulcan follows the gripen rule and no other contemporary plane has the tejas layout.
http://upload.wikimedia.org/wikipedia/c ... anform.JPG

while I am nobody to talk of wings, the too-short fuselage was a major design mistake imo and its hitting us now in lack of fuel to fit a more powerful engine, need for unsightly bulges all around to fit stuff from day1 (usually a/c do that in 2nd half of lifecycle)...and ofcourse the drag issue.

thats why I am very scared of the "smallest, lightest" thing...its possible for a austere GNAT, not for a modern 4th gen multirole fighter.

the Tejas is even shorter than the Mig-21 which everyone says is a very small fighter.

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Re: LCA Tejas: News and Discussions

Postby prashantsharma » 11 Mar 2015 14:00

Singha wrote:in the other deltas like Gripen, the sweep angle near the fuselage is more than outer part. in Tejas it is uniquely reversed.
even the avro vulcan follows the gripen rule and no other contemporary plane has the tejas layout.



Atleast one example exists, and a very successful / capable one at that... the Saab Viggen.

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Re: LCA Tejas: News and Discussions

Postby vardhank » 11 Mar 2015 16:41

astal wrote:I have little knowledge of aerodynamics but this article by Prof. Produt Das seems superficial and flies in the face of many observations that have nothing to do with aerodynamics.

What Prof. Das would like to see is a simple LCA bomb truck. Something like what the IAF wanted a long time ago. A poster named Abhibhushan (it appeared that he was ex IAF ), in an excellent post a few years ago, described his ideal two engined bomb truck, without any fancy new technologies. This would be close to Prof. Das's vision except for the single engine.

Such an aircraft, if designed 25 years ago and inducted 15 years ago would have served IAF well, it would be an indigenous upgrade to the Jaguar and offer an evolution path to an Indian MRCA. The Indian MRCA would have all the bells and whistles of a modern 4th generation aircraft including Delta wing with canard or wing sweep, AESA BVR radar, Quad digital FBW. The only problem would be to find a suitable engine or pair. Good engines were not available to us at the time and those available were underpowered, difficult to maintain or consumed too much fuel.

Fast forward 25 years and every 4 and 4+ generation aircraft has a delta wing configuration, rejected by Prof. Das. All the Eurocanards which the IAF covets are delta winged aircraft. Even without understanding aerodynamics, the question arises: Why are the all 4+ gen fighters delta winged if this is a step backwards.

The second thing that is difficult to understand is Prof. Das's dismissal of BVR capabilities. One explanation could be that Prof. Das only understands aerodynamics and is at sea with electronics and Radar. Not trusting BVR does not make its lethality go away. Every contemporary aircraft has a lot of emphasis on BVR, radar and tactics. Either every aircraft manufacturer and Air Force that drew these requirements are wrong or Prof. Das is clueless about many aspects of modern fighter design. I am guessing the latter.

The third thing that makes no sense is his criticism of composites. I have no explanation for this. This is another issue where every aircraft is moving to composites as they are light weight and durable. What could be wrong with that?

That being said, from a strategic and tactical perspective, I would really wish for the LCA MK2 to be focused for ground attack. With a little more fuel, some weight optimization and wing/fuselage tweaks(if needed), they could eliminate the need for MRCA and double the production of the LCA. I feel IAF already have one of the best 4th gen fighter aircrafts ever made in the form of the Su 30 MKI. We need decent 4th gen mud movers.

Another track would be to simultaneously work on a new version, the LCA MK3 that would be optimized for Air Combat. With minor changes for a modicum of stealth and the best possible ITR and acceleration aerodynamics, this fighter would fill in numbers for point defense and CAP.

The LCA suffers a bit from trying to be multirole, a good fighter and a good bomb truck. Trying to cram all these capabilities in a small, light frame has resulted in the compromises that the LCA must live with today. But looking at its performance, I would say it has come a long way and is ready, even in its present for, to serve many useful roles in the IAF and it can only get better. Prof. Das has his day in the sun. His opinions are stuck in the 80s and the world has moved on.


+1 to the second bolded bit. It's great that we've got the LCA to where it is, but I think it might be a neither-here-nor-there fighter. I've put up something similar in the Design Your Own Fighter thread, where I think we could develop a true "light" fighter along the lines of the Northrop F-5/F-20, either with two Adour engines or a single AL31, with simpler wings and a lighter frame, definitely a smaller frontal section with a smaller radar, largely a 'day fighter'. An option is to pare down the LCA itself, but I don't know how you'd do that. A third option is a bomb truck with the wing shape Prof Das recommends, which reminds me a lot of the F-16XL - possibly even to enlarge it with two engines.

Abhibhushan had put up that great post about the CAS-type aircraft; in a way, I can understand why he and Prof Das would want a Kiran/Gnat derivative - simple, with a single purpose, and hopefully quickly designed. The Kiran/Gnat solution might not be the right one, but a light fighter type like the F-5/F-20 thing I suggested might work. NOT a Hawk-type trainer, one step up from that, but not loaded down with multi-role aspirations fitted into "smallest/lightest" aspirations.

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Re: LCA Tejas: News and Discussions

Postby shaun » 11 Mar 2015 16:59

I guess we can do away with what the prof thinks about LCA , LCA in its present format is a formidable multirole fighter and have been put to serial production and hopefully within a span of 3-4 years we will see 2 squadrons flying. All the design efficiency and deficiency in the design will show up in due time and it will give us real feed backs helping us to refine it more .

Although there is no question on academic and professional qualification of the prof , but his skewed up views is based on some skewed up datas . As some one have said , his methodology is right , but you put wrong numbers and your calculation is wrong. Computational fluid dynamic and wind tunnel datas on Tejas is hard to come by and in aerodynamics you don't make assumptions . I will trust our resident experts more than any prof who have nothing to do with tejas or ADA.

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Re: LCA Tejas: News and Discussions

Postby vardhank » 11 Mar 2015 17:07

Bizarrely, the LCA and MMRCA problems seem to have exactly the same things wrong with them - it's as if we've learnt nothing. There are simply too many "needs/wants" heaped onto one airframe.

Re the LCA,
1) The Air Force NEEDED a force-filler, quickly - means immediate/quick availability, possibly high cost
2) The Air Force WANTED the best available - means high cost, especially if you want it quickly
3) The government wanted and needed to create indigenous fighter development and manufacturing capability - means plenty of time will be needed
4) HAL wanted manufacturing orders, but didn't necessarily need them (given Su-30 manufacture etc) - means lower cost, but possibly more time
5) The CAG wanted to make sure procedure was followed (very babu), and did not especially care about ability as long as it met cost parameters (especially true for the MMRCA) - means more time but lower prices

In isolation, none of these things are bad, but I don't think you can have ALL of them in one plane. In both cases, with both the LCA and MMRCA, the NEED seems to have been forgotten in favour of WANT. First make sure you have good, serviceable fighters that are in the air and available, THEN go for the technology, not the other way round. Developing a simpler fighter would've filled the numbers and done what was needed, but we wanted something exceptional in an exceptionally small frame. Why? This becomes even less forgivable with the MMRCA: given that this was meant to be a hedge against the LCA's failure, the entire emphasis should've been on getting good, serviceable fighters. Agreed it started with just looking for Mirages, but it quickly bloomed into the MMRCA circus, which went on and on, and has ended up with us either having to pay a ridiculous amount for the Rafale, or staying a client state of Russia. Some very serious questions have to be asked, of the IAF, government and the CAG. Something had to give, and no one showed the maturity to do so. With the MMRCA, why did we need it to be built here? Did we NEED ToT, which in any case has never actually worked? With the LCA, did we NEED our first fighter (disregarding the Marut, whose infrastructure and know-how had died anyway), to be a super-dooper fighter?

Right now, the best thing to do would be to forget any further 'cool' stuff on the LCA and just induct it. It's good enough, and WAY better than nothing. 100 Mk Is instead of 40, in the same time frame, or less. Then get in the Mk II, and keep improving the Mk I - making it lighter and more focussed on either A2A or A2G rather than multi-role stuff. No options. Some heads really have to be knocked together. Of course, it's never helped that our press is what it is, and knowledgeable people like Prof Das feel the need to show off their knowledge and muddy the issue. Oh well, this is India, no?

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Re: LCA Tejas: News and Discussions

Postby Cosmo_R » 11 Mar 2015 17:12

@Vardhank ^^^. On the spot except for the HAL bit. True, HAL doesn't NEED orders but it WANTS to make sure no one else in India gets them.

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Re: LCA Tejas: News and Discussions

Postby member_25400 » 11 Mar 2015 17:57

vardhank wrote:
astal wrote:a simple LCA bomb truck.
The LCA suffers a bit from trying to be multirole, a good fighter and a good bomb truck. Trying to cram all these capabilities in a small, light frame has resulted in the compromises that the LCA must live with today.


it might be a neither-here-nor-there fighter....we could develop a true "light" fighter along the lines of the Northrop F-5/F-20 An option is to pare down the LCA itself, but I don't know how you'd do that. A third option is a bomb truck
.. light fighter type like the F-5/F-20 thing I suggested might work. .



The thing is that all Air forces are going away from simple dedicated one role aircraft towards multi-role aircraft (tilted towards ground or air.)
The economics of the purchase drive very strongly towards that. Logistics too. Almost 2/3rds of the cost of the aircraft is lifecycle cost, instead of up-front cost. Having more cheap fighters saves on capital expense but increases pilot and maintainer expense as well.
Also, it is much simpler for planning and logistics to have one aircraft do everything rather than worry about availability and location of the fighter types, of the ground attack types and escorts and so on. It also allows for more flexible tactics/war gaming.
Having an aircraft be multi-role also allows you to order more of the type, taking advantage of economies of scale. Of course you have to have procurement and investment plan according to this also.

Yes, there are compromises in aircraft performance, but it can be offset by the other advantages. Over generations, some of this can be clawed back by avionics and payload updates. (goes both ways). of course, if you muck up the procurement, nothing can help you.

The F-20/F-5 you mentioned lost out to the F-16 in sales. The moment Reagan permitted the F-16 to be sold abroad, it was the death knell for Northrop's lightweight, simple, low volume F-20 fighter.

Where I agree is that the initial flight/version of our plane need not have been the super complex version. There could have been evolutionary improvement.

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Re: LCA Tejas: News and Discussions

Postby Akshay Kapoor » 11 Mar 2015 19:42

Re, the responses on Prof Das's blog, Ersaktivel gets carried away by rehashing wiki and media quotes and his knowledge of aerodynamics is inversely proportional to his passion for Tejas. I found the Retd Navy fighter pilot's comments much more credible. I am attaching a link to his latest comment. Indranil is he right about Tejas's ClMax and stall speed ? He says that negates the advantage of low wing loading. Apologies if this question is too simplistic without access to full data - I saw your response about the need for wind tunneling data.

Look forward to your post April 6 comments. I am attaching a link to his comment. Worth looking at. In essence he says:

- there are significant aerodynamic issues and a wing redesign is needed. But even with the issues Tejas is still better than Mig 21 because of of boresight missiles. His combat range estimate is pretty much what we estimated around - 350 km.

http://profprodyutdas.blogspot.in/2014/ ... mment-form

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Re: LCA Tejas: News and Discussions

Postby member_24684 » 11 Mar 2015 20:31

Akshay Kapoor wrote:Re, the responses on Prof Das's blog, Ersaktivel gets carried away by rehashing wiki and media quotes and his knowledge of aerodynamics is inversely proportional to his passion for Tejas. I found the Retd Navy fighter pilot's comments much more credible. I am attaching a link to his latest comment. Indranil is he right about Tejas's ClMax and stall speed ? He says that negates the advantage of low wing loading. Apologies if this question is too simplistic without access to full data - I saw your response about the need for wind tunneling data.

Look forward to your post April 6 comments. I am attaching a link to his comment. Worth looking at. In essence he says:

- there are significant aerodynamic issues and a wing redesign is needed. But even with the issues Tejas is still better than Mig 21 because of of boresight missiles. His combat range estimate is pretty much what we estimated around - 350 km.

http://profprodyutdas.blogspot.in/2014/ ... mment-form


That Known Retd navy pilot's real identity was revealed by long ago with the Support of Capt Aldrin and Lt.col Deltacam from WAB

he is still more active in the Baki owned IDF site

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Re: LCA Tejas: News and Discussions

Postby Sagar G » 11 Mar 2015 20:50

I can't comment about Prof. Prodyut Das aeronautical knowledge since that's not my field of interest and hence lack the required capability to comment on the same but some of the goat droppings that I can clearly figure out like the "ISRO and ADA case study" section and his "advice" about increasing the production rate to 60/ yr. :lol:

Professor sahib is a "theory ka sher" like many other IIT professors, nothing bad in being one we need them as well as sher's of different kind to achieve the set target but "theory ke shers" should be extra careful while dishing out generous advices to people working on field. Have seen a few instances when such "theory ke sher's" ended up with suddha desi gobar on their faces.

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Re: LCA Tejas: News and Discussions

Postby shaun » 11 Mar 2015 23:31

Akshay Kapoor wrote:Re, the responses on Prof Das's blog, Ersaktivel gets carried away by rehashing wiki and media quotes and his knowledge of aerodynamics is inversely proportional to his passion for Tejas. I found the Retd Navy fighter pilot's comments much more credible. I am attaching a link to his latest comment. Indranil is he right about Tejas's ClMax and stall speed ? He says that negates the advantage of low wing loading. Apologies if this question is too simplistic without access to full data - I saw your response about the need for wind tunneling data.

Look forward to your post April 6 comments. I am attaching a link to his comment. Worth looking at. In essence he says:

- there are significant aerodynamic issues and a wing redesign is needed. But even with the issues Tejas is still better than Mig 21 because of of boresight missiles. His combat range estimate is pretty much what we estimated around - 350 km.

http://profprodyutdas.blogspot.in/2014/ ... mment-form


well, mig-21 bison too have off-bore sight missile firing capability ..holy crap , we should have continued with mig-21 ..!! LCA , such a waste of money and time.


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