LCA Tejas: News and Discussions

negi · Post by **negi** » 12 Mar 2015 00:20

Professor Das has the benefit of hindsight , with his level of knowledge one can probably take up any AC today and say what could/should have been done differently to make it a better AC. In fact even I have never been a big fan of tailless Delta design but guys remember in late 70s and 80s Deltas were in vogue just because F-22s, F-35s and now PKFA are not tailless Deltas it would be unfair to say that Tejas is a dated design issue is we just took too long to make it . Having said that at this juncture none of it matters , it is now all about execution and getting the AC clear the FOC.

Singha · Post by **Singha** » 12 Mar 2015 07:01

Deltas perform well at high altitude which was for original point defence mission.

shaun · Post by **shaun** » 12 Mar 2015 07:32

With three consecutive start-ups of its engine after overnight soak in extreme cold (around -15ºC) conditions of Ladakh, that too without any external assistance, Tejas, the Indian Light Combat Aircraft has achieved yet another and a rare distinction. Starting the fighter aircraft under such extreme condition without any external assistance or heating is a technology breakthrough. The requirements become further stringent when the starting is to be done three times consecutively with a partially charged battery. Team LCA led by AERD&C of HAL, and members from ADA, NFTC, IAF, CEMILAC and DGAQA have succeeded in achieving this.

[youtube]https://www.youtube.com/watch?v=AmI-FTuGxtk[/youtube]

Karan M · Post by **Karan M** » 12 Mar 2015 08:14

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.

dont know whether you are being serious... but bison is woefully underprovisioned in terms of internal fuel capacity + its pylons (only 5) as versus the LCAs 7 + 1 and IFR capability. The lca can carry 2 ccm, 2 bvr missiles plus 3 drop tanks and has IFR. the bison 4 missiles and one drop tank. guess which is more capable!

shaun · Post by **shaun** » 12 Mar 2015 08:25

^^^

karan saab , i guess you have missed the action. Mig-21 assembly line will reactivated !! get a degree in aerodynamics , you will come to the same conclusion!!!

Karan M · Post by **Karan M** » 12 Mar 2015 08:28

are yaar what saab and all..
action...oh man, let me guess... prodyut das and his dramabazi is back again?
i didnt read the previous pages my mishtake

he has a bee in his oversized egotistical bonnet about the LCA, ADA and what not..

vardhank · Post by **vardhank** » 12 Mar 2015 08:40

barath_s wrote:
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.

Agreed, mostly. But I forgot to mention one important point:
6) The IAF wanted a fighter of a particular, small size, to fit into shelters made for the MiG-21 - again, in isolation a perfectly sound requirement, but it means that you have to give up on some abilities. Aiming for a MiG-21 +25 or even 50% is fine, but aiming for a MiG-21 + Mirage 2000 in a MiG-21 size is asking for too much, IMHO. Basically, like all our requirements, it was incompatible with a lot of others. I don't think you can simply deem that an aircraft be "multi-role." As if the Rafale and Typhoon, larger planes developed by mature aircraft industries, were multi-role from the start. As I understand, replacing the MiG-21s was the immediate need, followed by replacement of the Jaguar/MiG-27, not all in one fell swoop.

Re the F-5/F-20, from what little I know it seems the F-20 was killed off because it was very capable of stealing sales from the F-16, which would lead to higher per-unit costs for the USAF, not because of a lack of ability. It was supposed to be an excellent fighter otherwise.

maitya · Post by **maitya** » 12 Mar 2015 08:50

negi wrote:... In fact even I have never been a big fan of tailless Delta design but guys remember in late 70s and 80s Deltas were in vogue just because F-22s, F-35s and now PKFA are not tailless Deltas it would be unfair to say that Tejas is a dated design issue is we just took too long to make it ...

negiji you may want to go thru these two posts - wrt the LCA wing-geometry-design philosophy vis-a-vis other comparable designs (like Gripen) before you may want to make up your mind about good-bad-ugly things of wing design etc.
1) A mango-man-viewpoint can be seen here
2) and then some expert-viewpoint from Indranil can be seen here.

Pls remember turning rates are a very good indicator of how suitable the design is, for the primary role that is intended for it. For an aircraft that is being designed primarily for high-altitude interceptor kind of role, delta's remain the best - they do suffer (ironically because of the very same factor that helps it in the high altitude and high endurance roles - aka the larger wing area) while trying to make them do the diametrically opposite thing aka the low altitude mud-moving role.
But then again, in the era of relaxed static stability coupled with active/passive additional control surfaces like canards etc, those are more than adequately addressed.

Do note that some try to get the best of both the worlds (and thus compromising on both as well) which normally would be called as "path-breaking" etc. But the problem starts as soon as that "some" happens to be SDRE desis, then there's this incessant need of external validation etc – it’s a cultural thing, and it’s more acute with a generation (to which the good prof belongs to, betw), which thankfully are on the verge of fading away in a decade or so (shivji can provide a better perspective of this)!!

So chalta hien …

uddu · Post by **uddu** » 12 Mar 2015 09:32

LCA Tejas performing at the Aero India 2015 - Asia's Premier Air Show

LCA Tejas Winter Trials - Leh 2015

shaun · Post by **shaun** » 12 Mar 2015 09:41

vardhank wrote: Agreed, mostly. But I forgot to mention one important point:
6) The IAF wanted a fighter of a particular, small size, to fit into shelters made for the MiG-21 - again, in isolation a perfectly sound requirement, but it means that you have to give up on some abilities. Aiming for a MiG-21 +25 or even 50% is fine, but aiming for a MiG-21 + Mirage 2000 in a MiG-21 size is asking for too much, IMHO. Basically, like all our requirements, it was incompatible with a lot of others. I don't think you can simply deem that an aircraft be "multi-role." As if the Rafale and Typhoon, larger planes developed by mature aircraft industries, were multi-role from the start. As I understand, replacing the MiG-21s was the immediate need, followed by replacement of the Jaguar/MiG-27, not all in one fell swoop.

Re the F-5/F-20, from what little I know it seems the F-20 was killed off because it was very capable of stealing sales from the F-16, which would lead to higher per-unit costs for the USAF, not because of a lack of ability. It was supposed to be an excellent fighter otherwise.

who told you typhoon was multi role from the start. Better you should study the evolution of euro canards and also find the ASR of 1995 tejas to get a basic grip of what IAF actually wanted and where we are till date.

vardhank · Post by **vardhank** » 12 Mar 2015 10:06

Uddu, thank you. Most useful posts.

vardhank · Post by **vardhank** » 12 Mar 2015 10:08

@ Shaun

? That's what I said, no? It was NOT multi-role from the start.

shaun · Post by **shaun** » 12 Mar 2015 10:57

My bad, I am sorry.

vardhank · Post by **vardhank** » 12 Mar 2015 11:03

No worries

but thanks for the suggestion to read up more on the LCA ASRs, I genuinely don't know enough. Any good sources you recommend?

shaun · Post by **shaun** » 12 Mar 2015 11:18

This thread itself is a treasure trove.

ramana · Post by **ramana** » 12 Mar 2015 18:28

The best is enemy of good.

Every time LCA is ready, some sundry expert or useful idiot will claim its not the best and bring doubt causing swirl.

I have been following LCA since 1989. Read up articles by Hormuz Mama in Interavia and so on. The design kept evolving and worse changing. There never was accountability of requirements creep.
After all that is done to be pompous and dismiss it without considering the total picture is asinine.

ACM Mehra saab said "the bane of India is those who should talk are silent and those who shouldn't are most vocal"

Private conversation circa 1999.

I value the good prof professional teaching experience and thank him for that. But his comments on LCA are just rants.

I too want my LCA to be the littlest, lightest, fightingest machine.

A hummingbird with an eagles power!!!!

But am very happy with what is there and what is yet to come.

BTW, LCA is an unstable configuration, so unless you have access to all the coefficients and a very good computer you cant calculate using Aircraft Conceptual design formulae. Tried it in 1992 using Dan Raymer's book. And asked him why so? Then he pointed out the relaxed stability issues.

svinayak · Post by **svinayak** » 12 Mar 2015 21:38

ramana wrote:The best is enemy of good.

Every time LCA is ready, some sundry expert or useful idiot will claim its not the best and bring doubt causing swirl.

I have been following LCA since 1989. Read up articles by Hormuz Mama in Interavia and so on. The design kept evolving and worse changing. There never was accountability of requirements creep.
After all that is done to be pompous and dismiss it without considering the total picture is asinine.

ACM Mehra saab said "the bane of India is those who should talk are silent and those who shouldn't are most vocal"

Private conversation circa 1999.

I value the good prof professional teaching experience and thank him for that. But his comments on LCA are just rants.

I too want my LCA to be the littlest, lightest, fightingest machine.

A hummingbird with an eagles power!!!!

But am very happy with what is there and what is yet to come.

BTW, LCA is an unstable configuration, so unless you have access to all the coefficients and a very good computer you cant calculate using Aircraft Conceptual design formulae. Tried it in 1992 using Dan Raymer's book. And asked him why so? Then he pointed out the relaxed stability issues.

Almost all the tech in the LCA is not more than 5 years old. That itself is an achievement. Just to catch up India had to develop an aircraft with mil tech as new as possible.

This can replace all the 3-4-5 decades old aircraft in the inventory quickly.

Mitsy · Post by **Mitsy** » 12 Mar 2015 22:02

I never do comment much, being a layman technically, but the good professors comments and the ensuing discussion is intriguing.
I would rather read the holistic signals, which manifest clearly only over a period of time..
1. The AF commentary on Tejas.. Be it the Chief's comments at the latest edition of Aero India, the view of the test pilots (to be fair has been relatively positive throughout) or other relevant stakeholders - def min, other IAF sources - Yes, the tone of the commentary has changed to neutral to positive. Pl remember this is relative. Even ADA/ HAL have moved from being defensive abt the project to demanding additional production capacity.
2. The roadmap envisioned for Tejas is very different from what the professor suggests. Both ADA and IAF together have agreed on the same. It essentially carries forward the design philosophy of mk1 & incrementally improves upon it. Well, it cant be all that flawed then..

Just hope both IAF and ADA/HAL together find ground to leverage mk1 more.. we still have 7 yrs before mk2 SPs start rolling out.

Shreeman · Post by **Shreeman** » 13 Mar 2015 05:10

The good professor should not have written what he did. It reflects professional jeolousy and sour grapes. And nothing more. Here are the reasons why,

1. The good professor makes a hash of his arguments. He does not define a role, or parameters, or values that would lead to IAF ordering an LCA in the thousands. Mere conjectures that "role X would be fine" but "Y would not" dont mean horse manure. The LCA will not take a person to moon. In any form. What is the point of bringing the needs of an entire army and airforce upon one platform?

2. The LCA is delayed for non-technical reasons. An year to some magical FOC because a bolt on probe is not available? It will clntinue to be delayed, slow produced, and made a demonstration model. The navy will lust after Rafale M. The 29ks alone will be more than deck space available. There will be leaks regarding the lack of supercruise, OBOGS not being installed, Cobham not getting along with HAL, export permission denial of object k, IAF being unhappy.

3. "Real" -- if there is such a thing -- specifications or performance numbers will never be made public for anything. LCA wont get exported. No one will ever know what the 404 can do. What the cranked delta can do. What the radar can do. And so on. In an environment where pictures of the ADA loo are classified (not to say the F-16 loo is open to all), I ran out of salt years ago for just taking official reports, let alone the DDM.

4. The Migs will keep falling to the ground, inexplicably. Even twins. The Jaguars and Sus will join them in due time. This is not important.

5. Pure aerodynamic performance is not and has never been the deciding factor in any real life use. Production quality, sensor and weapons, training and tactics, and AVAILABILITY are just as important.

I could go on. But given that this, and the professor, and the discussion of the professor are all distractions. I better stop here.

disha · Post by **disha** » 13 Mar 2015 05:34

I have been following LCA saga since Sri Deve Gowda announced some 400 Cr and breathed new life in the project.

As Shreeman'ji correctly pointed out, Prof. Das is suffering from a feeling of being "left behind"., that is a feeling of robbed of ability to contribite! Here is where he knows he can contribute, can contribute positively and be proud of the outcome but never given a chance to participate. I feel for Prof. Das.

Further, Prof. Das comes from a different world - where there is no meaning to mathematical calculations unless it is tested out on a wooden scale model. Something subtle has happened, the world has changed and computers can do 3D CFD analysis - even in India - basically all the testing that needs to be done can be done in computer codes and verified in wind tunnel *if* required. This really puts him at odds, because he has the knowledge (the aeronautical part at very least) but not able to put it in action (due to lack of access and resources).

One thing that I do want to point out from Prof. Das's article is his bold statement that ADA/HAL should not worry about crashing the LCA. I agree., ADA/HAL has done an amazing job and should be proud of that. This is something which our DDM will never point out but we need to harp on it.

At the same time, any single untoward incident will jeapordize this whole program. Hence I am totally here with ADA/HAL on the way they are shepherding the program - it is akin to taking a lamb through a path surrounded by Hyenas. 1/2

Karan M · Post by **Karan M** » 13 Mar 2015 08:16

http://www.defenseworld.net/news/12376/ ... QJYnOGT7Ko

member_28932 · Post by **member_28932** » 13 Mar 2015 09:08

sankum wrote:LCA MK2 Weight Estimate based on latest data.

Empty weight= 6060Kg

Internal fuel= 3140Kg approx.

Clean Take off weight=10000Kg

External payload=5000Kg

MTOW= 15000Kg

6060 kg empty weight+ 3140 kg internal fuel+ 500 kg pilot wt/cannon ammo/ chaff/flare/weapons pylon wt+ 300 kg(2*close combat missile)+ 5000 Kg external payload=15000 Kg

This is very good. It seem that 90 KG design weight is slashed further, Few month back the figure was 6150 KG.

Singha · Post by **Singha** » 13 Mar 2015 09:37

>> Empty weight= 6060Kg

when the Mk1 itself is 6500 kg, and the Mk2 is 0.5m longer how can this be true?
at best they can optimize some stuff and hold it to 6500kg though even that will be very hard.
whatever could be made composite is already done.
perhaps the landing gear could shave a little weight.
OBOGS will add more weight.
AESA radars are usually heavier and need more powerful electric generator as well.

Shreeman · Post by **Shreeman** » 13 Mar 2015 09:49

Ditch all the ballast (how many x 100kg) ? Optimize the LRUs, Better landing gear, lighter wing? Hu knows.

negi · Post by **negi** » 13 Mar 2015 11:02

maitya wrote: negiji you may want to go thru these two posts - wrt the LCA wing-geometry-design philosophy vis-a-vis other comparable designs (like Gripen) before you may want to make up your mind about good-bad-ugly things of wing design etc.

Well all I said was I never liked tailless Deltas this was back in late 90s early 2000s I was in college then. I still do not like that design it has nothing to do with efficacy of the design , I liked the 29 as compared to the M2K and same with MCA as against the LCA. Delta wing is not an issue almost all modern fighters have a delta wing these days (compound/cranked whatever) I have never liked the ones without horizontal stabilizer it has nothing to do with Tejas . For that matter I do not like Euro canards as well.

That post was more about calf love than an opinion about platform, today if someone would ask me to pick the best dog-fighting platform in IAF I would probably pick the Tejas (yes even above the MKI), however for a joy ride and to keep one with me I will take the Mig-29.

Philip · Post by **Philip** » 13 Mar 2015 11:54

Until the first sqd. is delivered to the IAF ,where its capabilities are put to the test,so that future variants will improve performance,we are in the realm of speculation.HAL have to deliver and produce the aircraft on time and in large numbers/yr,not at the current snail's pace of 6+ aircraft/yr.That may make in time the entire LCA programme even inferior to that of the HF-24! The longer the arrival of the LCA even the MK-1s,the decade old tongue-in-cheek comment that the best replacement for old MIG-21s were new MIG-21s is still valid.One would be most interested to see how the LCA MK-1 has fared in combat against a MIG-21 Bison.Can we have some details from the IAF on that score,comparison between the two aircraft please?

The Sino-Pak JF-17 manufactured in Pak alone has now crossed over 50 aircraft.Exports of it are now being considered as a cheap solution to the needs of smaller nations.

Singha · Post by **Singha** » 13 Mar 2015 12:13

imo the Mk2 will be around 6800kg empty. fair enough, with reduced drag fuselage and more powerful engine with bigger wing fuel tanks, it should have some better parameters.

Kartik · Post by **Kartik** » 13 Mar 2015 14:08

Singha wrote:imo the Mk2 will be around 6800kg empty. fair enough, with reduced drag fuselage and more powerful engine with bigger wing fuel tanks, it should have some better parameters.

I would expect an even higher empty weight..more in the region of 7000-7300 kgs empty. The new engine weighs more, there are additional fuel tanks, there is an internal EW suite to be accounted for, a heavier AESA radar, an IR probe and more importantly, structural strengthening to carry an even higher payload than Tejas Mk1. I hope that the additional payload capability comes simply from a higher Max TOW, and not necessarily any additional strengthening..although invariably, higher loads lead to more strengthening of skins and load carrying structures. And don't expect lighter landing gear. As the MTOW goes up, so do the loads on the landing gear..besides, the IAF version Mk1 was never considered to have an overweight LG. So the scope for improvement may be negligible.

Optimization can account for some weight reduction, but to shave off any significant weight will require 2 things- investment for the effort required and a little more non-conservatism in analytical approaches. So far, investment hasn't been a very big issue, although conservative stress analyses certainly has been one. A cost vs gain approach is required..how much do you spend on shaving off a few kilos of weight? If you're willing to shell out a lot, somehow you'll find a way to shave off a little. the F-35 program had to incentivize, by offering engineers cash awards for ideas that were selected for weight reduction. The more weight saved, the bigger bucks the engineer who proposed that idea made.

BRFites shouldn't expect miracles. Weight growth and non-adherence to original target specifications is a fact in the aerospace industry. Expect a 7.5 ton empty weight Tejas Mk2 and if it is below that, you'll be pleasantly surprised. If you expect a 6 ton empty Tejas Mk2, you've clearly not compared other comparable fighters (such as the Gripen E) and are setting yourself up for a big disappointment.

Prof Prodyut Das makes a similar mistake. When he begins his "analysis" with such a flaw (calling the Tejas Mk1 overweight because it doesn't weigh 5500 kgs, which was its design goal in the 1980s), it pretty much ends up discrediting everything else he's written. Comparing the empty weights of the MiG-21 and the Tejas Mk1 but ignoring the range/payload gap between the two is intellectual dishonesty. The JF-17 is in the same empty weight/thrust class as the Tejas Mk1, yet he shows his ignorance by never quite owning up to this fact. Again, intellectual dishonesty. He has an agenda to grind and he goes about shamelessly. A pity that a mag like Vayu gives him a platform to peddle his BS.

Zynda · Post by **Zynda** » 13 Mar 2015 14:52

Karthik,
The Mk.1 has excessive Margins of Safety on many primary structures. This is understandable as the team had very little experience with designing an advanced fighter and thus wanted to have probably more than expected conservatism.

So if ADA is willing to go down on the degree of conservatism on Mk.2, selective beefing up of structures can be done as required.

I agree with you on the final empty weight of Mk.2 being around 10-12% higher than Mk.1.

pankajs · Post by **pankajs** » 13 Mar 2015 18:23

Saurav Jha ‏@SJha1618 25m25 minutes ago New Delhi, Delhi

MoD is fully cognizant of the potential of the Light Combat Aircraft programme. They are looking at ways to boost production rates.

Saurav Jha ‏@SJha1618 24m24 minutes ago New Delhi, Delhi

All stakeholders realize that it is needed in numbers. MoD is asking the IAF to draw up plans accordingly.

If true Joy ho!

Singha · Post by **Singha** » 13 Mar 2015 18:26

the only way to beat the never end curve of

overweight ->
lets stuff in a bigger, heavier engine for more power ->
burns more fuel ->
need more fuel tanks ->
extra weight ->

is to move to next gen engines which have higher dry thrust but consume noticeably less fuel and keep around the same dimensions and weight.

sankum · Post by **sankum** » 13 Mar 2015 22:31

More pragmatic weight estimates for LCA mk2 will be 7 T empty weight and MTOW at 16 T with rest weight data remaining the same or MTOW remaining at 15 T with reduced external payload of 4 T.

titash · Post by **titash** » 15 Mar 2015 07:41

http://www.janes.com/article/49101/aero ... ia-s-hawks

If this news is true, we'll be adding 100+ ASRAAM missile armed interceptors for close in air defence. During the cold war, the RAF used radar equipped Tornado ADVs to vector radarless sidewinder armed hawks to intercept soviet bombers.

While we'd prefer radar/BVR equipped LCAs, the Hawks can be useful in point air defence roles, and should be able to force mission kills (if not actual kills) on intruding PAF/PLAAF strike aircraft.

Singha · Post by **Singha** » 15 Mar 2015 07:57

The asraam will be self defence and hunting helicopters at low level. Rest of it for ground attack. We could use quad packed helina yum yum

But having combat hawk sqdns will take ac out of
Training....not sure if its feasible

titash · Post by **titash** » 15 Mar 2015 10:42

Singha wrote:But having combat hawk sqdns will take ac out of
Training....not sure if its feasible

Only during wartime sirjee...

Picklu · Post by **Picklu** » 15 Mar 2015 12:13

So, to address low sq no, we will arm hawks but not order additional LCA mk1?

Viv S · Post by **Viv S** » 15 Mar 2015 13:08

Picklu wrote:So, to address low sq no, we will arm hawks but not order additional LCA mk1?

Astounding isn't it? Especially given that the Hawk costs about $20 million each (compared to $26 mil for the Tejas).

eklavya · Post by **eklavya** » 15 Mar 2015 13:36

The primary role of the Hawk will remain AJT, and they will not be transferred to frontline squadrons. This will only provide some additional war time flexibility (and the roles to be performed will be quite limited). The incremental cost will obviously be much less than $20m or $26m per aircraft.

Sagar G · Post by **Sagar G** » 15 Mar 2015 14:25

Got to give it to IAF HQ's steadfast dedication to come up with new ways to put Indian money into furreign hands. Indigenous projects gets a no show of interest from IAF but it wouldn't waste any opportunity to bleed Indian economy with useless investments.

Buy more Tejas fighters !!! NOPE
Buy Indian BTT with the capability to be armed !!! NOPE
Give Britshits money to arm imported trainer !!!! FAQ YESSSSS

eklavya · Post by **eklavya** » 15 Mar 2015 14:38

How do you know arming the Hawk will be useless?