LCA News and Discussions

Kanson · Post by **Kanson** » 29 Jun 2010 13:01

Paul wrote:
I remember a team had come from Pratt & Whitney and examined Kaveri and commented "the design is 100% pure Indian". Ofcourse they did not help us with the remedies to overcome the problems engine had then faced. That comment was enthralling though not a happy one. It meant the Indians could reinvent the wheel. The time frame of development is geometrically narrowing, in the sense, 0 to 1.5% development consumes "X" time and 50% to 100% also consumes just "X" time. But 1.5% to approximately 50% consumes "5X" time. We are nearer to 50% capabilities, we are just one "X" time away from success. We had shown that in the space science.

I thought they were from GE...An article was published some ago referring to a visit made by leading US designers. (Paraphrasing here) They pulled their best designers, even the ones that were in retirement and had them come down to BGL to look at "Kaveri". Apparantly instructions were issued to just look at see but not offer any suggestions. They looked at the engine and made some general comments about the soundness of the design but nothing more...and went back.

IIRC, request was send to all engine houses, including GE. But GE didnt respond as it would tatamount to killing the exisitng projects with Tejas. It was from P&W. They pulled the old/retired guys as the current couldnt figure out what the GRTE was doing wrt Kaveri. So old guys looked the project and came with statement as finally they could able to understand what Indians were doing and is truly an Indian design. They too offered to help but it didnt fructify. I think, the offer from them were not concrete. I mean the promises were not great. This gave credit to the origial thinking behind the Kaveri.

Kanson · Post by **Kanson** » 29 Jun 2010 13:05

Sanku wrote:So Ajai Shulka said it, wow I am impressed, he also thinks that DRDO should not talk because "log kya kahenge" (what will people say) and quotes Matthew Hoey (of whom we should all be in awe of no doubt) to buttress the fact.

I am amazed that PoV can even be held. It should count for criminal negligence.

If it of any use, he expressed that as insitutional/unit thinking or somekind of mess talk, IIRC. You can clarify with him. It is meant only to say, this kind of thinking is prevalent in every organization..

Sanku · Post by **Sanku** » 29 Jun 2010 13:13

Kanson;

So you are saying that PoV is everywhere and not in DRDO alone? Perhaps but it is equally criminal, also the forces are constantly crying out for equipment, and no FORCES do not hold the view that war will not happen, Col Shukla is frankly not a valid data point, he is a loose canon, irrespective of which side he takes, he DOES not speak for the forces. Forces fully expect a war to be thurst on them on short notice and they keep disparing that their views are considered alarmist by the MoD/Babu/DRDO civilians.

Kanson · Post by **Kanson** » 29 Jun 2010 13:31

Sanku wrote:Kanson;

So you are saying that PoV is everywhere and not in DRDO alone? Perhaps but it is equally criminal, also the forces are constantly crying out for equipment, and no FORCES do not hold the view that war will not happen, Col Shukla is frankly not a valid data point, he is a loose canon, irrespective of which side he takes, he DOES not speak for the forces. Forces fully expect a war to be thurst on them on short notice and they keep disparing that their views are considered alarmist by the MoD/Babu/DRDO civilians.

Correct, just as Shukla's statement cannot be taken as valid data point, and may not represent the FORCES view point, Telang opinion cannot be taken as representative of DRDO and miscontructed as that, entire DRDO works like that. Hope you understand. I'm referring to your first post on this...http://forums.bharat-rakshak.com/viewto ... 10#p896510

Kanson · Post by **Kanson** » 29 Jun 2010 13:37

Vikram W wrote:Also remember here that the Shakti engine put in the Dhruv helicopter was also a total Snecma engine , with only an Indian name. who are these ppl fooling ?

You may come to know that when infact Kaveri is mature enough to join the forces...As you will be seeing, it will be in batches, like Kaveri-I, II, III etc...So you might understand that what happened was not a total Snecma engine boilerplated as Indian. You will get enough indication the amount of indigenous tech into the Kaveri which increases progressively as batch progresses.

Sanku · Post by **Sanku** » 29 Jun 2010 14:05

Kanson wrote: Correct, just as Shukla's statement cannot be taken as valid data point, and may not represent the FORCES view point, Telang opinion cannot be taken as representative of DRDO and miscontructed as that, entire DRDO works like that. Hope you understand. I'm referring to your first post on this...http://forums.bharat-rakshak.com/viewto ... 10#p896510

Fine, that is a valid point. I should not have used the word DRDO to represent Telang's views, especially given that even if true for GTRE it is still a subset of DRDO.

my mistake there, I will edit the original post if I still can.

Telang · Post by **Telang** » 29 Jun 2010 16:30

Is it a mistake to tear off Kaveri from LCA thread? Are we, in this Forum, already reconciled to the idea of Tejas never to have Kaveri in its belly? What a defeatist attitude, or is it just pragmatism? Why cant we have separate threads for Tejas nose wheel, wing tips, Tejas paint, and Tejas rivets,........ and exhaust vapours?? Some how it looks odd to me, and now please do not counter this, there is no need, I admit the above idea must be outrageously bohemian!!!!!!!!!!! Sorry I posted this.

Rahul M · Post by **Rahul M** » 29 Jun 2010 16:39

some people seem to be too sensitive, there's a reason why we have separate LCA and kaveri threads,the point of the kaveri thread is to gather all engine related development news at one place in view of its importance, not that it means kaveri has no relation to LCA(what inane logic)

the Indian military aviation and LCA and FGFA thread are different, surely that means we have given up on those fighters entering the IAF ?

final point : continue engine discussions to kaveri thread.

NRao · Post by **NRao** » 29 Jun 2010 16:48

Telang,

We did have one thread for LCA's paint, wheels, rivets, etc ................. the moderators (sorry mods) combined them into this one thread ............................ in and around 1999!!

So too with the Kaveri thread. It has been there since around 1999!!!

We ALL agreed on that format ............................ in 1999.

However, once in a while the discussion gets so strong that posters do not read all posts and continue to cross post.

WRT Kaveri and Tejas, yes, everyone on BR would LOVE to see the two together (since pre-1999), BUT, most of us have seen these games being played (games because that is how they appear to us from open source - we do not have insider's info). So, until Kaveri is mature enough (looks like LSP-6 is reserved for that type of work) - the argument goes - why not have the LCA Mk-II fly around in a mature, trusted engine (EJ/GE)?

When the Kaveri is mature enough then it can replace these engines. (Which is what the reports suggested just 2-3 weeks ago.)

Now it seems that the DRDO wants to check out the Ej/GE engines for the LCA Mk-II and replace them with an engine proposed with Snecma that does not even exist. Which by itself is fine, but it runs a certain amount of risk for the IAF - that the LCA Mk-II will/could/would be further delayed. That is a risk that the IAF does not want to take.

It is as simple as that.

Telang · Post by **Telang** » 29 Jun 2010 17:09

Folks, I was here in 1999 in a different Avtar, and not even a single day passed with out me reading LCA & Kaveri posts ever since. In fact those were my most favored bed-time stories, I couldnt sleep with out reading them it was agonising when there were no news. I know that some of you here are ALWAYS RIGHT.

Just a small clarification: Are discussions of EJ200 and GEF 414 part of LCA or Kaveri; or are there separate threads for each one of them? If they are part of LCA, then Kaveri will be incidental to their discussion and vice versa. My request to senior Gurus and grand masters is: "Discuss Kaveri separately, but dont make it a taboo here". Very difficult to make some arguments by surgically separating the incidental.

NRao · Post by **NRao** » 29 Jun 2010 17:16

The risks that the LCA carries with each of these engines is part of this thread.

Info/news/articles/bashing/beating each engine should go in the Kaveri/engine thread.

Gagan · Post by **Gagan** » 29 Jun 2010 18:34

Guys, any ideas on the new LCA cockpit design? Hope it is going to be space age like in the Rafale! [/jingo]

Gaur · Post by **Gaur** » 29 Jun 2010 18:40

^^
Its all speculation as of now but in the latest interview with Aviation week, ADA Director P.S. Subramanyam said:

The next one in line is LSP-5 and it will fly in the first week of August this year with slight modifications to the cockpit.

So, I am not expecting any huge changes.

Gagan · Post by **Gagan** » 29 Jun 2010 18:48

More like re-arrangement / re-alignment of the displays and controls etc.
He also mentions that the Night fighting ability will improve. How might I ask?
Dedicated monitor for FLIR? SAR?
Overall Larger display monitors?

This is what it is like today:

babbupandey · Post by **babbupandey** » 29 Jun 2010 19:35

Gagan wrote:More like re-arrangement / re-alignment of the displays and controls etc.
He also mentions that the Night fighting ability will improve. How might I ask?
Dedicated monitor for FLIR? SAR?
Overall Larger display monitors?

This is what it is like today:

The design looks so old, especially in comparison to Rafale. Also it has got so many buttons, giving it a very cluttered look

negi · Post by **negi** » 29 Jun 2010 19:43

^ Compare it with cockpits of AC in IAF service.

Gaur · Post by **Gaur** » 29 Jun 2010 20:44

babbupandey wrote:
Gagan wrote:More like re-arrangement / re-alignment of the displays and controls etc.
He also mentions that the Night fighting ability will improve. How might I ask?
Dedicated monitor for FLIR? SAR?
Overall Larger display monitors?

This is what it is like today:
The design looks so old, especially in comparison to Rafale. Also it has got so many buttons, giving it a very cluttered look

Rafale cockpit is in a class of its own as far as looks are concerned ( I am no pilot so I cannot comment on other issues). However, if you look at other cockpits ranging from F-22, F-16, SH to Mig-29, MKI etc, you would find that it "looks" basically the same with approximately same amount of buttons. However, if you have some gyaan regarding how the tejas cockpit design is "old", please enlighten us.

johnny_m · Post by **johnny_m** » 29 Jun 2010 22:11

Gripen has one of the neatest looking cockpits around. F 35 is not bad either. Then again you know with the French everything they make look good.

Kersi D · Post by **Kersi D** » 30 Jun 2010 21:22

Telang wrote:Folks, I was here in 1999 in a different Avtar, and not even a single day passed with out me reading LCA & Kaveri posts .

circa 1999
Once upon a time there was a LCA and there was a Kaveri
.....
......
.....
.....

circa 201X
And they lived happily after !!!! Inshah Allah

circa 202X
And they started swinging!!!!
Kaveri also went with MCA, HCA, XCA, YCA

and
LCA went with F 414, EJ 2000, Snecma XYZ, Klimov ABC. PW MNT etc

AND THEY ALL LIVED HAPPILY AFTER !!!!!!

K

Rahul M · Post by **Rahul M** » 30 Jun 2010 21:29

babbupandey wrote:
Gagan wrote:More like re-arrangement / re-alignment of the displays and controls etc.
He also mentions that the Night fighting ability will improve. How might I ask?
Dedicated monitor for FLIR? SAR?
Overall Larger display monitors?

This is what it is like today:
The design looks so old, especially in comparison to Rafale. Also it has got so many buttons, giving it a very cluttered look

get a picture of the same cockpit in night-time with all the LCD panels lighted up and you would call it at par with rafale.

bottomline : we still have some way to go as far as image building is concerned.

Sid · Post by **Sid** » 30 Jun 2010 22:49

"HF" designation for Tejas soon

http://angle-of-attack.blogspot.com/

Angle of attack has been informed that Hindustan Aeronautics Limited has forwarded a request for a new "HF" designation for its LCA- Tejas fighter aircraft. HF stands for Hindustan Fighter and is followed by a two digit number which indicate a year of some significance either to HAL, the aircraft or the nation itself. The last fighter to get the HF designation was HF-24 Marut which was India's first indigenous jet fighter.
The request contains various options for the number which will follow the designation. The numbers currently known to us are of the the year when the project started, first roll out, first flight, Bangladeshi Liberation war and Kargil war. One will be selected in few months time and will replace the infamous LCA tag. The LCA tag won't be used after that by the authorities. Other designations for indigenously produced aircrafts are HTT-Hindustan Turbo Trainer for Turbo prop trainers, HJT-Hindustan Jet Trainer for intermediate trainers and HT-Hindustan trainers for advance trainers.
Along with this update the Tejas is also ready for service in first quarter of the year 2011 and will be stationed in Bangaluru. The negotiations for new more powerful engines will also begin very soon with GRTE of DRDO putting forward its Snecma-Kaveri engine into the negotiations. The airforce for some reasons is upset with that and had recently accused DRDO for trying to slow down the progress of second version of Tejas.

saurav.jha · Post by **saurav.jha** » 30 Jun 2010 22:55

A newbie question..is IRST system for LCA developed already..?or, is still under development.

arya · Post by **arya** » 01 Jul 2010 22:44

jahejekafir

paralay.com

karthik · Post by **karthik** » 01 Jul 2010 23:18

The cockpit is under the process of redesign.There was an article named "LCA cockpit to be pilots dream"! Hope it doesnt end up just as a dream!

Anyone want to talk about LCAs maneuverability? Its seems to have an very slow turn rate compared to the JAS, was it designed keeping the TVC in mind? In earlier posts we used to image the LCA would have TVCs as promised but it never happened so far. So was the canard sacrificed for the TVC?

Indranil · Post by **Indranil** » 01 Jul 2010 23:52

Karthik thanks for bringing this discussion up. Let us talk categorically when you mean turn rate first!

For one let us not believe the TVC would increase the turn rate at a given speed. It will certainly let you do the turn much slowly and hence your radius of turn will be smaller.

Also, I noticed something which I shouldn't have missed for so long. Notice that the wing join is not a straight line. Given the width of the wing, is the chord must also bent? Does anybody know which airfoil the LCA is using ?!! Knowing that will help us analyse better! Also what are the advantages of such a wing shape! Given that the LCA flies level on its belly, the wing must always be at a small AoA. That will produce more lift. I don't think given the supersonic aerofoil, it would increase drag at small AoA, or will it?!

karthik · Post by **karthik** » 02 Jul 2010 01:28

indranilroy wrote:For one let us not believe the TVC would increase the turn rate at a given speed. It will certainly let you do the turn much slowly and hence your radius of turn will be smaller.

Tejas has a corner velocity where it has its best turn rate and best turn radius, i just hope its not too wide? TVC would help in lowering the turn radius at a given or lower speed if it is used in tandem with the elevons it would play its roll in improving turn rate and radius.

Also, I noticed something which I shouldn't have missed for so long. Notice that the wing join is not a straight line. Given the width of the wing, is the chord must also bent?

I am not sure about the chord in a compound canard delta wing, have you calculated where the mean chord lies?!!

Does anybody know which airfoil the LCA is using ?!! Knowing that will help us analyse better! Also what are the advantages of such a wing shape! Given that the LCA flies level on its belly, the wing must always be at a small AoA. That will produce more lift. I don't think given the supersonic aerofoil, it would increase drag at small AoA, or will it?!

[/quote]

The wing does seem to have a higher AOA near the canards as it was designed for increased lift coefficient for its size. These individual parameters would not let us know how it actually performs is unless we could calculate all the parameter involved in its rather unique wing structure. The compound canard does improve the life coefficient but i am not sure how it helps in maneuverability!

Shalav · Post by **Shalav** » 02 Jul 2010 01:58

Karthik,

Please enlighten us as to what you mean by "Its seems to have an very slow turn rate compared to the JAS..." Do you have numerical evidence to support this, or is it just something you feel?

Tejas has a corner velocity where it has its best turn rate and best turn radius, i just hope its not too wide?

Calculations show it is better than the Gripen w.r.t. both turn radius and instantaneous turn rate.

Indranil,

"...wing join is not a straight line..."

You are looking at wing twist. Used to distribute lift over the wing and maintain laminar airflow. Helps in preventing tip stall without using wing fences.

karthik · Post by **karthik** » 02 Jul 2010 02:10

Shalav wrote:Karthik,

Please enlighten us as to what you mean by "Its seems to have an very slow turn rate compared to the JAS..." Do you have numerical evidence to support this, or is it just something you feel?

My bad i should have asked before coming to a conclusion! That would be great if it does have a better turn rate, could you tell us what calculation and how is the compound delta wing in the tejas more maneuverable than one with movable canards?

I was refering to this video that is doing the rounds on youtube now! I know this is very amateur and i dont care if i get flayed for this but i hope some one could throw some light on this.

http://aircrafts.i-mix.info/?p=3152

Shalav · Post by **Shalav** » 02 Jul 2010 02:28

karthik wrote:That would be great could you tell us what calculation and how is the compound delta wing in the tejas more maneuverable than one with movable canards?

The formula to calculate corner velocity is : [(2 * nmax) * (W/S) / (ρ * CL,max) ]^½
nmax = g load on airframe * g
W = weight
S = wing surface area
ρ = air density
CL,max = maximum co-efficient of lift.

Once you have corner velocity you can calculate turn radius using : V^2/g * tan(B)
V = velocity
g = acceleration due to gravity
B = bank angle

based on turn radius you calculate time required for 1 degree (seconds/degree) of turn using : piV/180 * g * tan(B)
pi = value of pi
V = velocity
g = acceleration due to gravity
B = bank angle

1/(value of sec/degree) will give you turn rate in degree / second

karthik · Post by **karthik** » 02 Jul 2010 02:50

^^^ Have you worked out these parameters? Also do you know which airfoil the LCA uses to calculate the lift coefficient with respect to aoa?

Indranil · Post by **Indranil** » 02 Jul 2010 02:58

Shalav wrote: Indranil,

"...wing join is not a straight line..."

You are looking at wing twist. Used to distribute lift over the wing and maintain laminar airflow. Helps in preventing tip stall without using wing fences.

Thanks Shalav for pointing it out. I had read about the wing twist long time back. Hence it didn't readily come to mind. Actually I was also taken in by the fact that in most planes (leaving aside the chines) one sees that the wing root join is relatively "straight" and has very low AoA and the washout taking the wing tip to actually point downwards (negative AoA). Like here http://sandraceret.s.a.pic.centerblog.net/vjtwcna9.jpg or here http://cdn-www.airliners.net/aviation-p ... 343988.jpg.

However for the Tejas the wing root actually has a positive AoA and the wing tip is almost level. Brings me to a question, what would be the advantage of such a fit? If anything the wing root AoA would always be more than the AoA of the plane. Hence the maximum AoA achieved by the body will be a few degrees less that the stall angle of the wing!

Shalav · Post by **Shalav** » 02 Jul 2010 03:06

You should satisfy yourself so here are some numbers for you

altitude: 10 km
ρ = 0.413 kg/m^3 (calculated: based on ISA standard atmosphere table)
g = 9.80665
g load = 9g
B = 83.62 deg

W (kg)
HF = 5,500 + 1000 (fuel) + 1000 (armaments)
JAS = 6,620 + 1000 (fuel) + 1000 (armaments)

S (m^2)
HF = 38
JAS = 25.54+5.54 (main-wing + canard)

CL,max
HF = 7.0732
JAS = 8.0119

Let me know what numbers you arrive at (results will be in m/s)

Indranil · Post by **Indranil** » 02 Jul 2010 03:30

karthik wrote:TVC would help in lowering the turn radius at a given or lower speed if it is used in tandem with the elevons it would play its roll in improving turn rate and radius.

There are almost always used with the elevons. I know of but only two situations where the TVC deviation is opposite of elevon direction. In a single engine plane TVC can't induce any rolling effect. However in a twin engined plane the two nozzles are pointed in opposite direction to create the moment. Even here the left nozzle with work with the left elevon and the right nozzle will work with the right elevon. (1:10 in this video)

For the turns you can see how the TVC works in tandem with the elevons in the video I have posted here. Just before take off (0:12), just before the cobra (1:24), during the vertical rolls ( around !:38)

One use I know where the nozzles work in opposite order of the elevons is to fly the plane on its tail at very slow speed. One kind of keeps oscillating them so to provide no moment at all other than giving a bigger "foot print to stand on". The opposite order cancels any torque whatsover even along the longitudinal axis. Hence, it doesn't change the direction of the plane. You can see that between 0:35 and 0:50 in this video and again around the 2:00 minute mark as he is just about to pull out of the cobra.

The second use is for the "helicopter maneuver" at 2:12.
[youtube]-hq_RTaThNI&feature=player_embedded[/youtube]

I am not sure about the chord in a compound canard delta wing, have you calculated where the mean chord lies?!!

No

. I can't calculate till I know the aerfoil! Guys who did the 3D renderings of Tejas, any info?!!!

krishnan · Post by **krishnan** » 02 Jul 2010 14:19

LCA completes 1400 test flights

Gaur · Post by **Gaur** » 02 Jul 2010 14:41

indranilroy wrote:
I am not sure about the chord in a compound canard delta wing, have you calculated where the mean chord lies?!!
No . I can't calculate till I know the aerfoil! Guys who did the 3D renderings of Tejas, any info?!!!

I am not able to understand what info you need on the Tejas aerfoil. If its the aerfoil's shape and position you need to know, you can refer to these blueprints I had used to make the 3D model of Tejas. They do not show the lower part of the aerfoil but they do give the basic idea of its shape and position.
http://i698.photobucket.com/albums/vv34 ... 1278063100
http://i698.photobucket.com/albums/vv34 ... 1278063099
http://i698.photobucket.com/albums/vv34 ... 1278063100

K Mehta · Post by **K Mehta** » 02 Jul 2010 15:29

guys stop feeding the troll!
Eagerly awaiting tomorrow's roll-out of NLCA!

marimuthu · Post by **marimuthu** » 02 Jul 2010 19:12

K Mehta wrote:Eagerly awaiting tomorrow's roll-out of NLCA!

I thought it was on July 6

Indranil · Post by **Indranil** » 02 Jul 2010 19:34

Gaur wrote: I am not able to understand what info you need on the Tejas aerfoil. If its the aerfoil's shape and position you need to know, you can refer to these blueprints I had used to make the 3D model of Tejas. They do not show the lower part of the aerfoil but they do give the basic idea of its shape and position.
http://i698.photobucket.com/albums/vv34 ... 1278063100
http://i698.photobucket.com/albums/vv34 ... 1278063099
http://i698.photobucket.com/albums/vv34 ... 1278063100

The airfoil description is generally much more data intense about the curvature of the upper and the lower surfaces. For example the F-16 has NACA 64A204 airfoil at the wing root and also at the wing tip. One can easily obtain the description from the net for that airfoil.

One of the source is http://www.f-16.net/f-16_forum_viewtopic-t-12917.html. Scroll down to the download on the right hand side of the third comment.

Gaur · Post by **Gaur** » 02 Jul 2010 19:46

^^
I see. Then I am afraid that I cannot be of any help. I did the Tejas renders based only on the blueprints.

Indranil · Post by **Indranil** » 02 Jul 2010 21:59

The compound canard does improve the life coefficient but i am not sure how it helps in maneuverability!

Given that the AoA of the wing in the forward section is higher than at the back, the wing would try to pitch the nose up if the CG of the plane is behind the wing root join. Is there any open source about where the CG of Tejas lies at?