LCA news and discussion

nachiket · Post by **nachiket** » 08 May 2010 01:59

putnanja wrote:what is kaiser-aeroblog? can some one post a link about his comments on LCA?

PAF Air Commodore (retd) kaiser Tufail's blog. Link. He does mention later that the Relaxed Stability of the Mirage-2000 and Tejas mitigates the ill-effects of very-low aspect ratio wings.

Luxtor · Post by **Luxtor** » 08 May 2010 02:01

putnanja wrote:what is kaiser-aeroblog? can some one post a link about his comments on LCA?

Don't bother. That blog is from a website run by an ex paki pilot (paf) and is full of the usual paki bravado and paki centric garbage that is presented as expert opinion.

Ofcourse, what do you think a paki would say about the LCA?

The claims and opinions on that site (like many other paki sites) is like...the pakis can conquer the world with a blade of grass (if they get hungry, they can eat it too)

... but the Indians can't do anything right.

Kanson · Post by **Kanson** » 08 May 2010 02:27

kvraghav wrote:^^^
I too wanted to dig this up and went to wikipedia.It says that the lesser the aspect ratio,better is the manueverability.Can someone confirm on this?

As Luxtor mentioned it is blog maintained by PAF officer. So dont expect him to shower explicit praise on Tejas design.

In general, low-aspect ratio is good for manoeuvrability.

Tejas aspect ratio is ~1.75. But it is a cranked compound delta. And you cannot compare a compound delta with simple delta machine like Mirage-III, becoz the purpose of compound delta is to take care of the deficiencies associated with the usual delta wings. And there are so many articles, discussions which extolled the advantages of Tejas manoeuvrability and tight turns at low speeds due to crancked compound delta wing. As das mentioned, it has FBW system. And second thing, all this manoeuvrability depends on TWR too.

karan_mc · Post by **karan_mc** » 08 May 2010 06:52

Is it chaiwalha info or published info?

Info on TD-1 and TD-2 are documented ,while info on PV-1 is CNN (Chaiwalha News Network)

Picture of TD-1

Uploaded with ImageShack.us

shiv · Post by **shiv** » 08 May 2010 06:57

May I stick to my sarcastic cruelty and say something? Everyone in the military aviation business knows that all aircraft are a trade off. You have to reduce specs in one way to get better specs in another way. But we don't believe it unless the Americans say it. The Americans never say it - they only say "We are the best. We can do everything"

But the fact is that all aircraft designs will compromise on one thing to get another thing. So you can actually pick up any aircraft design and rip it apart as useless based on all the compromises it has made. A classic example is the Prodyut Das article i posted. I find it amusing to see Americans saying thrust vectoring is good for combat only terms of the maneuvers that F 22 can do, but not the maneuvers that Su 30 can do, while Indians and Russians have been saying that the Su 30 too has combat-worthy maneuvering ability and not just for airshows.

It is best to rest assured that if the LCA has 10 good design features it will have at least 10 compromises on other features that will be described as weaknesses. Please set this aspect ratio takleef aside.

RonyKJ · Post by **RonyKJ** » 08 May 2010 07:11

I am disappointed to hear that TD-1 has been dismantled. I feel it should have been preserved in an air museum. After all, it symbolised the rebirth of modern Indian fighter aircraft design.

rgsrini · Post by **rgsrini** » 08 May 2010 07:37

RonyKJ,
Here you go.
The King is dead... Long live the king!

To the left is a photograph of the first Tejas (TD-1) being prepared for burial. All essential and salvageable parts are being recovered from the (now somewhat battered) aircraft, before it moves to its final resting place in some museum or headquarters.

karan_mc · Post by **karan_mc** » 08 May 2010 07:54

RonyKJ wrote:I am disappointed to hear that TD-1 has been dismantled. I feel it should have been preserved in an air museum. After all, it symbolised the rebirth of modern Indian fighter aircraft design.

Dismantled in terms of its parts and other things which can be used again , bare airframe will make it to some airbase or museum soon

shiv · Post by **shiv** » 08 May 2010 09:08

RonyKJ wrote:I am disappointed to hear that TD-1 has been dismantled. I feel it should have been preserved in an air museum. After all, it symbolised the rebirth of modern Indian fighter aircraft design.

True - I must admit that TD 1 is closest to my heart and of all the LCA videos the one I have seen the most is TD 1 taking off, with people cheering from the side. That video is imprinted in my brain.

I had even created an animated gif of that repeating endlessly on my now dead Geocities page.

merlin · Post by **merlin** » 08 May 2010 09:52

Yes, TD-1 proved that India can do it too. The first one is always special.

nithish · Post by **nithish** » 08 May 2010 19:30

shiv wrote:
RonyKJ wrote:I am disappointed to hear that TD-1 has been dismantled. I feel it should have been preserved in an air museum. After all, it symbolised the rebirth of modern Indian fighter aircraft design.
True - I must admit that TD 1 is closest to my heart and of all the LCA videos the one I have seen the most is TD 1 taking off, with people cheering from the side. That video is imprinted in my brain.

I had even created an animated gif of that repeating endlessly on my now dead Geocities page.

here it is..enjoy

Austin · Post by **Austin** » 08 May 2010 19:50

Nice Video refreshes memory and the LCA looks beautiful in white

chackojoseph · Post by **chackojoseph** » 08 May 2010 20:42

Thank You Nitish.

PratikDas · Post by **PratikDas** » 08 May 2010 22:09

Yes, thank you Nithish.

Hip, hip...

Praveen · Post by **Praveen** » 08 May 2010 22:40

Nithish, I converted that video from .dat to avi for youtube using a trial version of some conversion software. That's the reason for the logo on the left. Nice to see that it's still there.

rahuls · Post by **rahuls** » 08 May 2010 22:53

Nice video, thanks Nithish. I remember the first LCA flight reported on StarNews (was it Vishnu Som??), iirc produced by NDTV then, I went ballistic. My mom was like, wtf happened....she didn't know the importance.

Couple of questions from the above video posted by Nithish.

1. Is the pitching movement of the craft when launched (2.27-2.35min) normal ?
2. The grid pattern on the wings, are they some sensors or just the paint scheme ?
3. What are the pilot options in case or chute deployment failure while landing, can he still stop ?

thanks

nithish · Post by **nithish** » 08 May 2010 23:15

Praveen wrote:Nithish, I converted that video from .dat to avi for youtube using a trial version of some conversion software. That's the reason for the logo on the left. Nice to see that it's still there.

so you uploaded the original video? all credit to Praveen saar only

Praveen · Post by **Praveen** » 09 May 2010 01:14

nithish wrote:
Praveen wrote:Nithish, I converted that video from .dat to avi for youtube using a trial version of some conversion software. That's the reason for the logo on the left. Nice to see that it's still there.
so you uploaded the original video? all credit to Praveen saar only

Nah, I just converted and uploaded. I think Shiv was the one who gave the download link for the video in *.dat format.

Kersi D · Post by **Kersi D** » 09 May 2010 16:33

shiv wrote:May I stick to my sarcastic cruelty and say something? Everyone in the military aviation business knows that all aircraft are a trade off. You have to reduce specs in one way to get better specs in another way. But we don't believe it unless the Americans say it. The Americans never say it - they only say "We are the best. We can do everything"
.

NO
The Americans only say "We are the best. We can do everything. AND hence all of you ( Norway, Netherlands, Belgium and now India !!! )must do whatever we do e.g. buy C 17"

K

chackojoseph · Post by **chackojoseph** » 09 May 2010 18:05

LCA as UCAV

I don't know if its old or new news, but, thought you should know.

vasu_ray · Post by **vasu_ray** » 09 May 2010 21:41

can they not install an FBW on the Mig-21? With hundreds of sorties being made by IAF they could generate the requisite data in less than 2 years time by instrumenting 10-20 Migs or few from operational squadrons in different climate zones

rookie pilot on a Mig-21 while landing has some computer help

integration into landing aids resulting in all weather operation

the transition from LCA to UCAV can be fraught with crashes if recent UAV crashes are to go by, Mig-21 can serve as the guinea pig

Kaveri can be mounted on a Mig-21 for that fighter envelope testing

Migs in UCAV mode can still hide behind a Su for the stealth attack, even surprising is a suicidal Mig

Agreed, if we went back 10 years in time, perhaps this thought would have been more saleable

srs · Post by **srs** » 10 May 2010 06:30

We can use UCAV mig 21's as decoys. let porkis waste their missiles on them.

shiv · Post by **shiv** » 10 May 2010 07:10

vasu_ray wrote:can they not install an FBW on the Mig-21? With hundreds of sorties being made by IAF they could generate the requisite data in less than 2 years time by instrumenting 10-20 Migs or few from operational squadrons in different climate zones

rookie pilot on a Mig-21 while landing has some computer help

integration into landing aids resulting in all weather operation

the transition from LCA to UCAV can be fraught with crashes if recent UAV crashes are to go by, Mig-21 can serve as the guinea pig

Kaveri can be mounted on a Mig-21 for that fighter envelope testing

Migs in UCAV mode can still hide behind a Su for the stealth attack, even surprising is a suicidal Mig

Agreed, if we went back 10 years in time, perhaps this thought would have been more saleable

Vasu Ray I don't have an exact answer but I have some views. One of the reasons for using FBW is to have an unstable aircraft that is prone to doing some wild maneuvers that would make it go out of control without FBW. That is why FBW aircraft can be made super-maneuverable. The LCA is one such unstable platform.

The MiG 21 is basically stable but designed for speed and maneuverability and one of its biggest problems is that it has a high approach speed for landing. It's landing speed is like the top speed of a Dakota. Here is what late Wingco Suresh wrote about the MiG 21
http://www.bharat-rakshak.com/MONITOR/I ... uresh.html

MiG-21, although a high demand aircraft, is docile and has no aerodynamic vices. It has excellent handling characteristics and has served to provide very valuable flying experience to a large number of IAF pilots. Some like the previous and the present CAS swear by the aircraft. It is the docility of the aircraft that not only generates a good bit of confidence but also encourages forays into exceeding the limits of the stipulated flight envelope. In air combat maneuvers, many inexperienced pilots have got into trouble without realizing it. At high angles of attack, the induced drag increases sharply and unless the angle of attack is quickly reduced, the aircraft develops a high rate of descent, which cannot be arrested with the power available (even with reheat). Added to this, there is no protest from the aircraft like severe shudder, wing rocking. etc, prevalent in other types of aircraft. This gives a feeling of well-being and a number of pilots did not recognize the danger in time to take recovery action or eject.

You ask if FBW can be retrofitted on the MiG 21. I don't know the answer to that question. I suspect a major redesign would be needed, and if a major redesign is done it is perhaps best to come up with an entirely new fighter. Just my guess.

I would not worry about the recent UAV crashes. They can and do occur. All flying machines can crash especially UAVs that are being used in suboptimal weather and suboptimal launch and landing conditions that are risky or impossible for regular aircraft and often being flown by trained but non flying army/navy men

I personally think the LCA to UCAV idea would be far easier, cheaper and quicker than MiG 21 to UCAV. Once could use a scaled down model of an LCA with the same aerodynamic characteristics and largely similar software to carry PGMs on hazardous SEAD missions. I love the idea.

chackojoseph · Post by **chackojoseph** » 10 May 2010 07:18

What vasu_ray is actually trying to ask is a kind of "auto pilot" system in MiG-21 and is using FBW as a generic term.

Kakarat · Post by **Kakarat** » 11 May 2010 12:18

LCA-Tejas has completed 1354 Test Flights successfully. (11-May-10).

* LCA has completed 1354 Test Flights successfully
(TD1-233,TD2-305,PV1-242,PV2-140,PV3-213,LSP1-59,LSP2-148,PV5-12,LSP3-02).

shukla · Post by **shukla** » 11 May 2010 14:43

Kakarat wrote:LCA-Tejas has completed 1354 Test Flights successfully. (11-May-10).

Thanks for the update!

sunilpatel · Post by **sunilpatel** » 11 May 2010 18:31

Kakarat wrote:LCA-Tejas has completed 1354 Test Flights successfully. (11-May-10).

* LCA has completed 1354 Test Flights successfully
(TD1-233,TD2-305,PV1-242,PV2-140,PV3-213,LSP1-59,LSP2-148,PV5-12,LSP3-02).

2nd Test flight of LSP-3

vina · Post by **vina** » 11 May 2010 18:40

There was one more flight today. I got buzzed at around 1:30 in the afternoon.

karan_mc · Post by **karan_mc** » 11 May 2010 19:16

Hope LSP-4 flies soon ,other then flight updates this thread will be pretty much dead for now

vipins · Post by **vipins** » 12 May 2010 00:35

vina wrote:There was one more flight today. I got buzzed at around 1:30 in the afternoon.

Around 11:00 am also,I saw one over koramangala area.

Vikram W · Post by **Vikram W** » 12 May 2010 02:30

Anyone wanna enlighten us on the design philosophy behind the gap between the engine intakes and the fuselage. There is a grill which leads to a opening on the top of the wing and on the bottom end is just fastened to the fuselage. Ive never seen something like this in other planes and am wondering what the use is of an opening like this ( reduce lift ?? ) . Also i would think that this would start resonance at high wind velocities.

senior members ?

Raman · Post by **Raman** » 12 May 2010 03:09

The gap is to ensure that the boundary layer from the fuselage is not ingested into the intake. There is also an intake splitter plate to separate the flow at the intake. The boundary layer is slow/sluggish/low energy in contrast to the free stream, and will case severe flow distorsion if allowed to mix with the free stream in the intake/diffuser.

The "grill on the top" that you refer to is a device to get rid of that same boundary layer air that is not ingested into the intake. The low pressure area on top of the wing sucks the boundary layer up and through that "grill".

Vikram W · Post by **Vikram W** » 12 May 2010 03:26

Thanks Raman, that solved this mystery for me

any other planes who have a similiar design ?

Kartik · Post by **Kartik** » 12 May 2010 05:28

wizard wrote:Anyone wanna enlighten us on the design philosophy behind the gap between the engine intakes and the fuselage. There is a grill which leads to a opening on the top of the wing and on the bottom end is just fastened to the fuselage. Ive never seen something like this in other planes and am wondering what the use is of an opening like this ( reduce lift ?? ) . Also i would think that this would start resonance at high wind velocities.

senior members ?

Every aircraft that does not feature the latest in this technology, the Diverterless Supersonic Intake (DSI) such as the F-35, JF-17 and J-10's latest variants (which instead have a bump near the intake), features the "gap". Its actually called a "splitter plate". The purpose has been identified by Raman- to prevent the turbulent flow at the boundary layer from being ingested into the air intake and causing distortion and a drop in coefficient of pressure inside the air channel.

I must also add that the "grill on the top" is a means to ensure that at even at high angles of attack, there is a constant stream of air flowing over the wing-roots through the air channel. So basically this turbulent air between the splitter plate and the fuselage is drawn out over the top of the wing. This turbulent airflow generates vortices that re-energizes the boundary layer and consequently, flow separation occurs at much higher angles of attack. And as a result of that, the stall angle (angle of attack at which aircraft wing will not generate lift) is increased. It’s a very smart solution to the problem of having such a large delta wing and no canards to generate the vortices.

As for not having seen such a "grill" on other aircraft, you just haven't seen it closely on other aircraft. You'll find similar (concept being the same) splitter plates on all jet fighters apart from the three I mentioned above. the construction may not be the same but they all have it if they're capable of supersonic flight. just look at any fighter closely and you'll see that its intake is not flush (attached directly) to the fuselage. The thickness of the boundary layer at its maximum speed dictates the distance that separates the intake from the fuselage.

I'm also quite sure that the Chinese did some IP theft in this regard from the US (probably academic espionage), because the time lag between the R&D and productionising of the DSI for the F-35 and its appearance on the FC-1 prototype is very suspect. And I can hardly believe that such a unique concept was in work at the same time in US and China.. the Americans first tested the DSI on an F-16, but the Chinese were directly able to implement it on a prototype FC-1. See, the initial FC-1 design did not have DSI intake - it had a splitter plate. Apparently they had some issues with the FC-1's design, and went in for major re-design work and when it came out it had a LERX and a DSI intake. Supposedly helps in reducing RCS signature..although the LCA takes a different approach in this regard that does the job even better- the LCA has a Y and S (serpentine) air channel inside it. The compressor face is buried deep inside and with such a winding air channel, hardly any radar wave will bounce back out and even if it does, it will be attenuated quite a bit.

shiv · Post by **shiv** » 12 May 2010 06:17

Mirage 2000 intake showing splitter
J-10 intake splitter

Vikram W · Post by **Vikram W** » 12 May 2010 07:08

I get wise everyday

is this the best forum or what ?

vina · Post by **vina** » 12 May 2010 13:59

Bhai log, why is jahaaj-e-kuffar flying idhar-udhar today ?. I got buzzed for the 3rd time today . Now just a few seconds ago. And definitely once in the morning and maybe one more at around noon.

Lot of flying being done huh ?

rohitvats · Post by **rohitvats** » 12 May 2010 14:00

vina wrote:Bhai log, why is jahaaj-e-kuffar flying idhar-udhar today ?. I got buzzed for the 3rd time today . Now just a few seconds ago. And definitely once in the morning and maybe one more at around noon.

Lot of flying being done huh ?

Noon time was a MiG-21....

Singha · Post by **Singha** » 12 May 2010 14:19

at night around 11pm when all you 'leaders/directors/poohbahs' are sleeping or settling back with single malts,
I am still at work. lately I have noticed a AN32 type doing touch and go circles at night repeatedly.

why is this done at HAL, when a full fledged training base is there in Yelehanka?

derkonig · Post by **derkonig** » 12 May 2010 15:14

^^^^
Being SDRE, it must be cowering in the dark of the night away from the TFTA MRCA contenders at Yelahanka..