LCA is Named Tejas!!!

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putnanja
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Re: LCA is Named Tejas!!!

Post by putnanja »

Aviation majors woo HAL over engine deal
Scientist at the Hindustan Aeronautics Limited (HAL) working on the indigenously produced Jet Trainer Aircraft (JTA) project are facing an unusual problem.
Three giant engine manufacturers have reportedly been pushing vigorously for their case lately. Considering that the total project would cost an estimated Rs 500 million, it's a deal anyone would like to grab.

Until now HAL was considering engines offered by the US and French firms for the JTA. A prototype that used the French engine was even tested recently. But scientists say a Russian firm too has pitched in with a toned down version of the engine being used in its Su-30 fighter jets.
George J

Re: LCA is Named Tejas!!!

Post by George J »

Err whats a JTA the article talks about recently tested aircraft with french engine, that be an IJT.

I didnt know that the russians were offering the AL-55 (toned down AL-31) for the IJT (JTA)?
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Re: LCA is Named Tejas!!!

Post by NRao »

No, we have not run out of acronyms. Smae AC, rest asured.

I do not know if I should trust this DDM. However, two Snecma engines vs. a derated, non-TV, single Ruski engined AJT. Difficult to believe that the Ruski engine will be downloaded into the IJT - just too much redesign I would imagine.

Uncle is too quite for this time of the year. What's cooking?
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Re: LCA is Named Tejas!!!

Post by Umrao »

The compressor, which generated an EPR of 19.5:1, also suffered from vibration problems that contributed to the test engine achieving only 1,200h of its projected 8,000h test run time. A shorter 250h test effort is planned with a partially redesigned compressor for 2003, including simulated high-altitude tests at Russia's Central Institute for Aviation Motors in Moscow.
This could be from

1) Manufacturing requires more Precision in

a) The shaft of the compressor
b) the impeller
c) balancing
d) The housing and the compressor (resonance frequency)
e) bearings.

(this is where Tim the tool man comes into picture)
d) better bearings.
*********
added later
some more info here
http://www.swri.edu/4org/d18/mechflu/planteng/gasturb/desassur.htm
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Re: LCA is Named Tejas!!!

Post by Umrao »

agupta>> Saab Agree and disagree.

I am assuming our guys are top notch in design, analysis, CAD and Math modeling.

Our weakness is in (general) materials, manufacturing within very very close tolerances consistently.

So I assumed design was correct, modeling was correct but we still needed precise manufacturing and materials.

I know that flow pattern designed, desired and achieved could be at variance.
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Re: LCA is Named Tejas!!!

Post by Kuttan »

Considering that the total project would cost an estimated Rs 500 million,
$11M for an entire aircraft project? I think Rajeev Srinivasan hit the nail on the head when he pointed out that the desi media have almost no competence with numbers, except maybe for election results.
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Re: LCA is Named Tejas!!!

Post by Kuttan »

So the test engine ran for 1200 hours, and achieved a 19.5 overall pressure ratio. Which is probably as high a pressure ratio as you want in an engine meant for a supersonic fighter anyway (21.5 sounds good if they can get it..). Now if they tell us what the Turbine Inlet temperature was in some other leaked publication, "we" can guess all the rest about the LCA's projected performance and component efficiencies :eek: . So I suggest that DRDO folks shut up about the Kaveri beyond what they've revealed already.
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Re: LCA is Named Tejas!!!

Post by Umrao »

my real worry is that ( I am kinda super paranoid, but think of the amounts of monies that are involved, present and future if kaveri succeeds) what if Ivan saab (apna engine ko) unglee kar diya tho?
***
historic read
http://www.rugbytown.co.uk/history/whittle1.htm
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Re: LCA is Named Tejas!!!

Post by Vanahan »

PR of 19.5 is way too low for normal design-point operation of Kaveri-type engine. (Just check the specs for base F-404) I presume the tests were being conducted at this particular load setting. Achieving much higher PRs should be no problem. The issue is maintaining efficiency and design life. The max. thrust capacity of almost any modern-day fighter is open-source information. Just relax, folks. This is part and parcel of R&D engineering.

Added:
The need to invest in extensive and expensive research facilities is a must if India is seriously interested in becoming an aerospace power. Just to name a few engine development facilites that are a must for any contender: Hi-Altitude Test Chambers, Static test-beds, Specially instrumented test-cells for combustor rig-tests, Wind-tunnels and Planar Cascades, Flow diagnostics (laser PIV, PLIF etc,) labs that can characterize nozzle fuel sprays, vaporization, mixing etc., Dedicated compressors to supply air(of sufficient PR and flowrates) for all these test facilities etc., etc., the list just goes on.

Where is India in this regard? There needs to be scientific organization, and clear intent that can only be brought about by substantial investments by the Government of India. I just don't see why if we can afford to spend billions of dollars on dozens of Su-30MKI or Mirage 2000 jets, we don't set-up integrated facilities of the kind seen in Germany, Canada, USA etc. by expending a few more billions. What we need is a shot in the arm. If we get serious, I would not be suprised to see a MCA, and perhaps even its successor flying in the next decade.
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Re: LCA is Named Tejas!!!

Post by RonyKJ »

AFAIK the kaveri engine and kabini core were run for over a 1000 hrs at GTRE (sea level tests) before being sent to Russia. If there was a compressor problem it would have been detected at GTRE. So my guess is that the lack of compression showed up at high altitude tests, either at low temperature-low density or at high temperature-low density. This kind of deficiency would only show up when the engine is tested in a facility that can supply low density air which is what a High Altitude Test Facility does. GTRE most probably did not have the facilities to do such tests in India even though ISRO has a HATF somewhere. This is a natural progression of the design and it seems like the redesign that was done actually put them ahead since the engine ended up being lighter! This redesign exercise neatly explains the huge time delay between when the engines were sent to Russia and until now.
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Re: LCA is Named Tejas!!!

Post by ramana »

N^3, There is an article in Interavia circa late 1980s that gives the full low down on the Kaveri engine. It is based on a talk by the head of GTRE and is written by H.P. Mama. You should find it in the back issues and a look at Engineering Index.
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Re: LCA is Named Tejas!!!

Post by Kuttan »

"vanahan".. welcome. (new name? member number is too old...)

Time for me to be cautious around here, I see... :eek:
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Re: LCA is Named Tejas!!!

Post by ragupta »

In the meantime, the hype machinery- deliberate or incidental - that keeps obfuscating the issues and hinting that we're almost there does more damage than good.

It has its own important role to play!. Not completely unneccessary.
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Re: LCA is Named Tejas!!!

Post by Marcos »

Hey Shiv..... video is simply superb and tks for making it and posting over here...
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Re: LCA is Named Tejas!!!

Post by Marcos »

hey can someone post the pict from the naming of LCA...... in which Vajpayeeand other pose with the LCA team .....
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Re: LCA is Named Tejas!!!

Post by Kuttan »

Yeah, what did they do, like getting the drunken wife of an Admiral to break a bottle of (falsely labeled) "champagne" on the bow and say "I name thish ship Tejash"? Did ABV throw a cococnut at the nose?
Guest

Re: LCA is Named Tejas!!!

Post by Guest »

For future reference, the article is:

"The GTX-35VS turbofan for India's LCA" by Hormuz P. Mama, Interavia, Vol: 43, No:4, Page 357, April 1988.

It's a one page article. I don't have a OCR scanner... so i'll just put in the highlights:
</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> article grew out of discussions with GTRE director Arun Prasad.</font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> overall pressure ratio could be increased from 21:1 to as much as 26:1 </font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> "convergent engine nozzle will be fully variabe from 80 percent rev/min onwards." ( don't know what this means.... direct quote... sounded important :D )</font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> blade material suitable for turbine entry temperature of 1650K (with a DMRL developed thermal barrier coating)</font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> higher TETs can hopefully be achieved with single-crystal turbine blades.</font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> blades to have minimum service life of 400 hrs</font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> cost comparable to F404 if 400 (!) are ordered.</font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> core should run in 1988 or early 1989. First complete engine should run in 1990. </font></li>
  • <font size="2" face="Verdana, Helvetica, sans-serif"> 13 prototype engines in all are to be built by 1994, when type approval is expected.
    </font></li>
<font size="2" face="Verdana, Helvetica, sans-serif">i repeat, this info was current in 1988. Interestingly, the term Kaveri is never used... it's always "-35VS" or the full form GTX-35VS. What year was the "Kaveri" designation chosen?
Originally posted by ramana:
N^3, There is an article in Interavia circa late 1980s that gives the full low down on the Kaveri engine. It is based on a talk by the head of GTRE and is written by H.P. Mama. You should find it in the back issues and a look at Engineering Index.
George J

Re: LCA is Named Tejas!!!

Post by George J »

Originally posted by manku thimma:
For future reference, the article is:

"The GTX-35VS turbofan for India's LCA" by Hormuz P. Mama, Interavia, Vol: 43, No:4, Page 357, April 1988.
Did Dr. Prasad provide a timeline for testing and delivery of the first Kaveri in the article?
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Re: LCA is Named Tejas!!!

Post by Umrao »

http://memslab.eng.utoledo.edu/~jreed/jgts/

from University of Toledo.

just plug in the data provided by Manku you have Kaveri in full bloom.

( warning: I think the simulator applet still has some bugs)
Guest

Re: LCA is Named Tejas!!!

Post by Guest »

george, i've put in the timeline in the original post above. in fact, i am not yet done adding all the bullet items...
Originally posted by George J:
Did Dr. Prasad provide a timeline for testing and delivery of the first Kaveri in the article?
Guest

Re: LCA is Named Tejas!!!

Post by Guest »

A few thoughts about the LCA.

Have you noticed that the Non-After burning power of Kaveri is lesser than the Non after burning power of F-404. (While the afterburning power is higher.)

Also, I have tried to look at the pictures of LCA and Mirage 2000 to compare the two designs. People are saying that LCA is a tail less delta winged design. Even after, inspecting the two planes closes several times, I am not seeing the difference. Someone help me here.
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Re: LCA is Named Tejas!!!

Post by Ashutosh »

Originally posted by Venkatesh:
Also, I have tried to look at the pictures of LCA and Mirage 2000 to compare the two designs. People are saying that LCA is a tail less delta winged design. Even after, inspecting the two planes closes several times, I am not seeing the difference. Someone help me here.
This is from a total armchair scientist, so might be totally off the mark.

Mirage-2000 is a "normal" tail-less delta.

LCA is a "cranked" tail-less delta. Check the leading edges of the wings - they are not in a straight line from the root to the tip of the wing. There might be more in the Mil-Tech archives though.
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Re: LCA is Named Tejas!!!

Post by Guest »

Also the Mirage 2000 seemed to have a small (very small) canard.
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Re: LCA is Named Tejas!!!

Post by MahaPazi »

Originally posted by Venkatesh:
Also the Mirage 2000 seemed to have a small (very small) canard.
Those are not technically canards as they are not lifting surfaces or for control. These strakes I think are there for improving the high angle of attack charectaristics by reenergizing the boundrylayer on the main wing at high angles of attack. And the mirage and LCA are different, very differnent one has to use ones eyes.... ;) .
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Re: LCA is Named Tejas!!!

Post by Victor »

Here is a piece on the origins of the Kaveri:

"...for which GTRE has attracted considerable world interest--the GTX37-14U.

The GTX concept has overcome the power loss problem which occurs in high ambient temperatures, such as to be found in many tropical areas around the world including India. The demonstator model was manufactured and assembled at GTRE, and from the very start of its bench running proved to be an outstanding success. Based on it, the GTX37-14U(B) by-pass version is now being developed. The GTX is expected to provide the basis for development of a suitable engine for use in the forthcoming Light Combat Aircraft.

GTRE is well-endowned with test facilites, and conducts aerodynamic research on combustion turbine engine components. There are twin engine test beds for engines up to 22,000 lb (10,000 kg) thrust, a high Mach number test bed to simulate high-speed low-level flights in high ambient temperatures, test rigs for checking blade vibration, shaft/carcass testing, spinning, etc. and facilities to test and calibrate fuel system components.

The fabrication facilites at GTRE are impressive and in addition to conventional machine tools there are Electro-beam welding plants, electo-discharge and NC machining, multi-spindle blade milling, and vacuum melting, to name but some. Processes have also been developed for cutting and forming components made from nickel cobalt, titanium and other advanced alloys...."

Source: IAF magazine, 1981. The GTX37-14U testing began in 1977.
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Re: LCA is Named Tejas!!!

Post by Arun_S »

Originally posted by Venkatesh:
A few thoughts about the LCA.

Have you noticed that the Non-After burning power of Kaveri is lesser than the Non after burning power of F-404. (While the afterburning power is higher.)

Also, I have tried to look at the pictures of LCA and Mirage 2000 to compare the two designs. People are saying that LCA is a tail less delta winged design. Even after, inspecting the two planes closes several times, I am not seeing the difference. Someone help me here.
Tail-less means there is no tail plane for pitching attitude control (unlike F16 that is also delta wing but has a tail plane)
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Re: LCA is Named Tejas!!!

Post by Raman »

I'm pretty sure that the F-16 is not considered to be a delta. A better example of a delta with a tail-plane is our own MiG-21.
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Re: LCA is Named Tejas!!!

Post by Ashutosh »

Jagan, Rakesh, I've noticed the LCA Image Gallery sections haven't been updated in almost 2 years ... the most recent picture there is of KH2001 ... any reasons for not updating them with the new pictures released of all three airframes?
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Re: LCA is Named Tejas!!!

Post by Badar »

Hi,

I have tried to look at the pictures of LCA and Mirage 2000 to compare the two designs. People are saying that LCA is a tail less delta winged design. Even after, inspecting the two planes closes several times, I am not seeing the difference. Someone help me here.

Venkatesh, You dont notice a difference because both are tailess delta wing designs.
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Re: LCA is Named Tejas!!!

Post by davidn »

Originally posted by Rajesh:
I'm pretty sure that the F-16 is not considered to be a delta. A better example of a delta with a tail-plane is our own MiG-21.
I don't think you can get much more of a NON-delta fighter than the F-16. Only the L159 is a better example.
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Re: LCA is Named Tejas!!!

Post by Raman »

Originally posted by Rajesh:
I'm pretty sure that the F-16 is not considered to be a delta. A better example of a delta with a tail-plane is our own MiG-21.
Here is some information straight from the horse's mouth: http://www.f-16.net/reference/versions/f16_lwf.html:
Different wing planforms
Four different wing planforms -- straight, swept, variable, and delta -- were reviewed. The variable-geometry wing was rejected because of its high weight and complexity. The delta wing had the advantage of low weight per unit of area and low wave drag, but was ultimately rejected because of its high drag-at-lift and trim drag penalties. A low-sweep, straight wing was finally chosen because it was thought to offer the best combination of good maneuverability, high acceleration, and maximum lift to ensure good altitude performance.
I guess the confusion arises because the blended wing-body complex makes the leading edge strakes look like they are part of the wing, giving more of a "delta-like" appearance.
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Re: LCA is Named Tejas!!!

Post by JTull »

Couple of new pages/pictures from ADA website (which is much faster now) outlining future variants:
LCA Navy page(picture)
LCA Trainer page(picture)

Couple of pictures (part of the animation) on this page seem to show night-time flights.
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Re: LCA is Named Tejas!!!

Post by Roop »

Originally posted by Badar:

You dont notice a difference because both are tailess delta wing designs.
True, but I think (of course I'm speculating here) that all this talk about the "difference" in the wing designs of the two planes (LCA and M2K) pertains to the fact that the Mirage wing has a constant sweep angle (i.e. from wing root to tip) whereas the LCA wing leading edge has two distinct "sections" with different sweep angles.

If that's not it, I fail to see any big difference between the two planes (which otherwise look remarkably similar to my untrained eye).

BTW, Badar, good to see you dragged out of lurkdom on this topic. What does it take to make you participate more often? If you don't shape up, I may have to sic Narayanan on you. :)
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Re: LCA is Named Tejas!!!

Post by Vriksh »

It seems in the cranked delta of the LCA the first sweep of the wing ie the one closer to the wing root is a major control surface... we can make out large airelons/elevators (whatever you call them there)

AFAIC I think it is a Canard conjoined to the wing... my reasons

1. The sweep is more perpendicular to the airflow... and a large control surface there will more easily harvest control from the airflow...

2. It functions much like a canard... without the inherent drag at high speed... when the control surface is tucked in... ie not disturbing the aerodynamic shape of the wing...

of course this is just a conjecture...
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Re: LCA is Named Tejas!!!

Post by Kuttan »

Can't see either link (Navy or Trainer) but as I recall, the TD-5 concept was the Navy one, and it had all these multiple gizmos on leading edge and trailing edge, and the close-coupled canard.

The break in sweep along the leading edge produces a strong vortex which will create suction on the wing at high angles of attack. And very "interesting" roll characteristics as the angle of attack is increased. Maybe the canard will help in this respect.

That will be some control system to develop!! - and to train to fly :D )
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Re: LCA is Named Tejas!!!

Post by Raman »

The first NLCA (Samudra Tejas?) will be PV-5, not TD-5.
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Re: LCA is Named Tejas!!!

Post by Sumeet »

Hey guys just had few questions for you:

1) Is Lockheed still assisting ADA for development of FBW control System ?

2) Will the FBW software has to be changed when Kaveri is fitted into LCA ? Any idea how long will it take to fix Kaveri into LCA ?

3) Any idea about what control algorithm is used by LCA for throttle control ?
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Re: LCA is Named Tejas!!!

Post by srai »

Originally posted by Rajesh:
The first NLCA (Samudra Tejas?) will be PV-5, not TD-5.
Actually according to the ADA website it will be NP1 and NP2 for naval prototypes. PV5 will be the 2-seat trainer.
LCA Programme involves building and flight-testing of two Technology Demonstrators – TD1 and TD2 (both already airborne) and five Prototype Vehicles (PV to PV5), the last being a two-seat Trainer version, towards operational clearance including weaponisaion.

A Naval version of the LCA capable of operation from an aircraft carrier is also under development. Two Naval Prototypes (NP1 and NP2) are proposed to be built and flown to obtain clearance for deck operation. FSED of Naval version is expected to be initiated concurrently with the ongoing LCA Programme.
Source: http://203.200.38.99/adaweb/Activities/LCAProduction/lcaproduction.html

This ADA webpage "Activities" section has plenty ( :) ):
http://203.200.38.99/adaweb/Activities/activities.html
:D :D :D
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Re: LCA is Named Tejas!!!

Post by merlin »

The ADA site is very informative and educational. Makes one realize the sheer amount of work involved in fighter aircraft design and development. And we did most of it alone, after the embargo following Pokharan-II! Here's wishing Pokharan-III and Pokharan-IV (to start with!) :D
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Re: LCA is Named Tejas!!!

Post by member_201 »

Please continue all further LCA discussions in the General Aerospace thread or start a new LCA thread - ONLY if it really necessary. Thanx.
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