LCA news and discussion

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Vikram W
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Re: LCA news and discussion

Postby Vikram W » 07 Jun 2010 03:08

the article indeed is a relevation. That the Tejas is getting to the home stretch is nice to read , but what was eye opening was :-
1. the mach 1.4 ceiling
2. the weight
3. the sourcing of the fbw system. ada/drdo fave been claiming its their innovation ( or so i thought)

if you read the article before that about the J 10 , i like the fact that the chinese dumped their j9 fighter because it was taking so long. and i guess the other thing we can learn from the chinese is that we should be concurrently be developing 2-3 planes rather than putting all our eggs in the tejas.

about time that mca got funding i guess

mandrake
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Re: LCA news and discussion

Postby mandrake » 07 Jun 2010 03:23

IIRC the fbw was in consultancy with LM, but after pokhran all hell broke on the team, it was re-designed from scratch with whatever experience the personnel had. Mach 1.4 is as per some media reports, as the pdf says, the authenticity of these media reports are questionable till LCA attains IOC and finally FOC.

Karan M
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Re: LCA news and discussion

Postby Karan M » 07 Jun 2010 03:29

The article is junk grade, there are a bunch of hokey claims in it, that even I can make them out. It seems to be a collation of Indian media reports on the LCA, garnished with some of the authors own commentary.

That you all are taking it as some sort of truth..well..

As far as I know, Lockheed took over Martin Marietta's contract for the FBW, and that cooperation was stopped thanks to Pokhran. The ADE developed hardware was also confiscated. The current FBW has been developed in India both hardware and software, but to speed things up, a consultancy agreement has been promoted with EADS, which should speed testing. But EADS has gone on record stating they will only assist/advice in terms of sharing general practise and audit as necessary, but will not be transferring technology or proprietary systems.

mandrake
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Re: LCA news and discussion

Postby mandrake » 07 Jun 2010 04:22

The JV with EADS is to speed up the flight testing, a benchmark to expedite flight envelope testing requires some sort of previous data-bank which we dont have as this is our first fbw endeavor. It is not even remotely linked with developing the fbw with EADS. It is always better to bring in someone with experience in the table while testing some specific envelope so that things do not go wrong in an already erratic surrounding.

NRao
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Re: LCA news and discussion

Postby NRao » 07 Jun 2010 05:04

mandrake wrote:The JV with EADS is to speed up the flight testing, a benchmark to expedite flight envelope testing requires some sort of previous data-bank which we dont have as this is our first fbw endeavor. It is not even remotely linked with developing the fbw with EADS. It is always better to bring in someone with experience in the table while testing some specific envelope so that things do not go wrong in an already erratic surrounding.


Small grip: "consulting" with EADS and not JV.

Also, it is not just envelope/s, it is to lay out the best possible testing time table - PM sort of. Sequencing tests so that they get the most of out the tests in the shortest time and money.

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Re: LCA news and discussion

Postby Manish_Sharma » 07 Jun 2010 06:16

I loved this article, especially this part:

Due to the fast tempo of mastering the latest
technology in aircraft building showed by the
Indians, the LCA design specifications looked
impressive. So, while at the initial stage of the
program the design empty weigh was estimated
at 6,000 kg, then due to optimism in wide coalplastic
use the Indians decreased the weight to
the record low for a fighter of the class – to 5,500
kg, which seamed rather possible. The composite
materials were supposed to be used in the wing,
empennage and control surface design.
The percent of the composite materials used
in the LCA roughly twice exceeded that of the U.S.
F-22A Raptor fifth generation fighter and its Soviet
analogue MiG-MFI jet.
For a comparison, the Saab
JAS 39 Gripen with a structure close to that of
the LCA and a similar engine
(Svenska Flygmotor
RM12 based on the same F404) and a radar was
6,620 kg, that is 1,120 kg more. At the same
time, the internal fuel tanks of the Indian aircraft,
according to advertizing brochures, was to accommodate
2,400 kg of fuel compared to 2,270 kg of
the Saab aircraft. The LCA fuel efficiency was 0.44
compared to 0.34 of the Jas 39.
The LCA predecessor
in the Indian Air Force, MiG-21bis (empty
weight – 5,350 kg), was fitted with the R-25-300
augmented turbojet engine with the thrust of 7,100
kgf and had only 1,790 kg of fuel in internal tanks
(fuel efficiency also 0.34). It is little surprise that
the LCA practical range of 2,000 km was to be
close to that of heavier fourth generation foreign
fighters (F-15 and F-16)
and be much better than
that of not only MiG-21bis (1,250 km), but also of
Gripen (1,700-1,800) km.


Yummy! what nice morning it is!

shiv
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Re: LCA news and discussion

Postby shiv » 07 Jun 2010 06:21

Austin's link says quite a lot about the J 10 which is what I found interesting. I had a very cursory read of the LCA article - about which there was less new information and some inaccuracies. The author puts the empty weight of the LCA LSP as 7000 kg and says that none of the Air Staff requirements have ben met. I am not sure about the weight guesstimate but that fact that requirements have not been met is known.

But we have spoken of all this in the past, Unless industry is given a chance it cannot perform. Peacetime is the best time to give industries a chance. If you look at the 1914-18 time frame and the 1940s - you find that immature technological innovations had to be translated straight into production line equipment because there was a war going on and there were sometime disastrous consequences of this.

Europe and the US and Japan have seen trial by fire. When you have men being killed every day by an enemy with superior equipment there is no time for tenders, trials and import, or to curse your own industry for producing something that is 15% overweight. Either you use it or have nothing. That was the situation that Europeans and the US found themselves in. India has never been in that situation - we have always had the urgent import option and it is stated cheerfully and shamelessly as a sort of truism that the Indian war machine will grind to a halt after 1 month, but the Pakistani machine would have stopped two weeks earlier. I think we have all heard this one.

NRao
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Re: LCA news and discussion

Postby NRao » 07 Jun 2010 06:41

Shiv,

That issue is from Jan, 2009!!!!

I think it is very crucial that people post the date of articles - just so that we do not get confused.

Vikram W
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Re: LCA news and discussion

Postby Vikram W » 07 Jun 2010 07:56

Are there any indian aircrafts using divertless intakes ? MK2 should have this :)

Austin
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Re: LCA news and discussion

Postby Austin » 07 Jun 2010 07:58

Shiv I agree with what you say even if this bird is over weight and can carry ( for assumption sake ) half the ammo in Mk1 it should be seriously pursued else we will never overcome the learning curve.

And yes the Tejas article is slightly dated.

Here is Col Ajai Shukla responding to a blogger on some of the criticism on Tejas quoting some unnamed Sr IAF Officer

Anonymous 09:40: a more powerful engine can solve many problems, but not every problem.


So the question that begs is what issues have been observed in the flight testing so far , what has been addressed and what is that cannot be address even beyond a powerful engine ?

shiv
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Re: LCA news and discussion

Postby shiv » 07 Jun 2010 08:41

Austin wrote:So the question that begs is what issues have been observed in the flight testing so far , what has been addressed and what is that cannot be address even beyond a powerful engine ?


I personally wouldn't bother about the little details. I am sure the Air Force and industry will reach some sort of solution or accommodation provided they work together for common goals.

After Tejas Mk 1 enters service it will be used with other aircraft and its strengths and weaknesses will rapidly become known as happened with the HF 24. The IAF has worked with at least two aircraft that offered little capability on paper. The Gnat did not even enter service in its country of origin and the MiG 21 was just a supersonic dart armed with two faulty Sidewinder copies. Both the Gnat and MiG 21 became successful because tactics were worked out and changes were made in conjunction with manufacturers.

But a comment on the article - it appears to me that the LCA is likely to be a pretty stealthy aircraft.

Austin
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Re: LCA news and discussion

Postby Austin » 07 Jun 2010 10:24

^^^ Yes by virtue of its small size and application of RAM it has lower RCS , Offically the RCS of Tejas is quoted as 1/3 of M2K.

More than RF and IR stealth of Tejas , I think it is the Visual stealth of Tejas will be a great plus point thanks to her small size . On the few occasion that I have seen her fly it found it visually a very difficult aircraft to keep an eye on ( granted I am not a trained AD gunner or spotter ) compared to Su-30 which is a very easy aircraft to keep your eye on

Rahul M
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Re: LCA news and discussion

Postby Rahul M » 07 Jun 2010 10:52

Vikram W wrote:the article indeed is a relevation. That the Tejas is getting to the home stretch is nice to read , but what was eye opening was :-
1. the mach 1.4 ceiling
2. the weight
3. the sourcing of the fbw system. ada/drdo fave been claiming its their innovation ( or so i thought)

if you read the article before that about the J 10 , i like the fact that the chinese dumped their j9 fighter because it was taking so long. and i guess the other thing we can learn from the chinese is that we should be concurrently be developing 2-3 planes rather than putting all our eggs in the tejas.

about time that mca got funding i guess

no revelation about it, I guess some of the meaning might have been lost in translation but ADA has been very open about the help it got. the LCA control laws were developed in India by Indians. if you take coaching for an exam does that mean your teacher took the exam for you ? what's worse, the CLAWS developed by our scientists undergoing tests in US were not returned to us post pokhran ! :evil:
LM's help was in consultancy and we also bought the associated hardware from US at first (moog IIRC) although I believe some have been developed in India since.

LCA has touched 1.6 mach more than once according to the test pilots.
the most ridiculous point was saying the payload would be 1500-2000 kg, to make a point that it was same as mi-21. that was absolutely laughable.

Austin
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Re: LCA news and discussion

Postby Austin » 07 Jun 2010 11:21

So can we confirm that Tejas Mk1 indeed carries a payload of ~ 4T and all the flight test done yet has proven the payload capability , which is to say it can carry ~ 4 T ?

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Re: LCA news and discussion

Postby Rahul M » 07 Jun 2010 11:35

3.5T for Mk1 is the reasonable figure. we did the calculations in this thread a few months back. Ajai also mentioned that figure later I think.

KrishG
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Re: LCA news and discussion

Postby KrishG » 07 Jun 2010 12:03

From Ajai Shukla 2008 article:

The Tejas LCA: improving performance with the current F404 engine

2. Reduction of Tejas' weight.

The LCA’s designers say that the removal of telemetry instrumentation, which is essential during flight testing, will bring the Tejas’ weight down by as much as 300-400 kilos. Re-engineering some of the displays and sub-systems within the cockpit will lop off another 300 kilos; the weight reduction of 600-700 kilos is expected to allow the carriage of more weapons.

There is a lack of understanding about what the Tejas’ weight is, since all kinds of figures are bandied about. Let me clarify: The 10.5 tons that I wrote about in my last post is the total weight of the Tejas, with full fuel on board; all 7 pylons fitted but not carrying weapons; and two outboard missiles being carried. The maximum payload of the Tejas is 3.5 tons… carried on its pylons. This could be armament or external fuel tanks; if external fuel tanks are fitted, the weight of fuel will correspondingly bring down the weapons load carried.

But there’s a catch! The maximum take-off weight of the Tejas is 13 tons. So if you load the maximum payload of 3.5 tons onto the 10.5 ton fighter, your weight of 14 tons is beyond the maximum take-off weight. So you’ll have to shed one ton… or either internal fuel or external fuel/armaments. That’s what happens when a fighter’s weight goes beyond what was originally planned.

So the reduction of 600-700 kilos may not actually go into making the Tejas more manoeuvrable. This shaved off weight may be made up by allowing the Tejas to carry (close to) its full capacity of external fuel-cum-armament.

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Re: LCA news and discussion

Postby vasu_ray » 07 Jun 2010 12:25

a noob question, how far/long can the LCA glide without losing altitude if it shuts off its engine at its max speed? say it will try to compensate by increasing the AoA

can it lose an IR missile if the engine shielded by a vector thruster points away from missile approach angle? and then re ignites the engine when the threat passes

the not-losing-altitude req. is to ensure terrain hugging simultaneously evading radio emissions from other types of missiles

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Re: LCA news and discussion

Postby Singha » 07 Jun 2010 12:41

um I thought engine shut => no electrical power => no power for FCS to move actuators / fly by wire stuff and the FCS itself needs power.

with a unstable fighter design, I would imagine the tejas might fall like a stone ?

sachinkrgarg
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Re: LCA news and discussion

Postby sachinkrgarg » 07 Jun 2010 12:43

Gurus,
I am new to this forum but have keen interest in airforce, aircrafts and rockets. I have one question on LCA testing. My concern is that how much of this testing is valid when even the engine of aircraft is not finalized. Will all parameters like Weight, balance etc not change rendering most of current testing as invalid?

many thanks for your ideas.

Austin
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Re: LCA news and discussion

Postby Austin » 07 Jun 2010 12:49

Thanks Guys , 3.5 T looks quite reasonable , 2x 1Kg A2G weapon and rest AAM one centerline 800 L tank.


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