LCA news and discussion

Tilak · Post by **Tilak** » 25 May 2009 23:12

Ajay K wrote:
marimuthu
Post subject: Re: LCA news and discussion

^^^It does not look like tejas at all.

Yeap, its Chinna thambi (M2K) and Mirage III (?).

You are right on both counts.

shiv · Post by **shiv** » 26 May 2009 05:53

Ajay K wrote:
marimuthu
Post subject: Re: LCA news and discussion

^^^It does not look like tejas at all.
^^^It does not look like tejas at all.

Yeap, its Chinna thambi (M2K) and Mirage III (?).

Mirage III and Kfir. The Kfir has canards

Tilak · Post by **Tilak** » 26 May 2009 05:58

shiv wrote:Mirage III and Kfir. The Kfir has canards

Shiv saar, Mirage III RS (experimental) has canards too..

http://www.aircraftresourcecenter.com/A ... alk411.htm

shiv · Post by **shiv** » 26 May 2009 06:41

Tilak wrote:
shiv wrote:Mirage III and Kfir. The Kfir has canards
Shiv saar, Mirage III RS (experimental) has canards too..

http://www.aircraftresourcecenter.com/A ... alk411.htm

Good catch. In fact it looks like a French AF Mirage 2000 and a Mirage III RS

Kfir

Mirage 2000

Mirage 5 (export version of III)

Sorry about the digression.

Aditya_M · Post by **Aditya_M** » 29 May 2009 00:05

The *second* aircraft (further from the view point) has leading edge slats. Single piece, full length. Neither the M3 variants nor M2K have the same. The Tejas does. Also, check the bits next to the air intakes, the think extensions that separate the intakes from the fuselage are tell-tale Tejas.

dipayan · Post by **dipayan** » 29 May 2009 01:26

Aditya_M wrote:The *second* aircraft (further from the view point) has leading edge slats. Single piece, full length. Neither the M3 variants nor M2K have the same. The Tejas does. Also, check the bits next to the air intakes, the think extensions that separate the intakes from the fuselage are tell-tale Tejas.

The shape of the engine nozzle seems too wide to be that of the Tejas though. Plus the distance of the trailing edge of the wing from the nozzle seems to big to be that of the Tejas.

narayana · Post by **narayana** » 29 May 2009 10:01

LCA-Tejas has completed 1118 Test Flights successfully

LCA-Tejas has completed 1118 Test Flights successfully. (26-May-09).

* LCA has completed 1118 Test Flights successfully
(TD1-233, TD2-305,PV1-196,PV2-124,PV3-144,LSP1-48,LSP2-68).
* 196th flight of Tejas PV1 occurred on 25th May 09.
* 68th flight of Tejas LSP2 occurred on 25th May 09.

LSP-3 and PV5 will add more hours for IOC and FOC,but no sign of them,according to Ajai Shukla it should be ready by Dec -08 almost 6 months passed

And one more thing i observed LSP-1 always flew less then any other,is it being used only for critical functionality testing?.

neerajb · Post by **neerajb** » 29 May 2009 10:17

dipayan wrote:
Aditya_M wrote:The *second* aircraft (further from the view point) has leading edge slats. Single piece, full length. Neither the M3 variants nor M2K have the same. The Tejas does. Also, check the bits next to the air intakes, the think extensions that separate the intakes from the fuselage are tell-tale Tejas.
The shape of the engine nozzle seems too wide to be that of the Tejas though. Plus the distance of the trailing edge of the wing from the nozzle seems to big to be that of the Tejas.

The most striking feature why that plane is not Tejas is it's PURE DELTA wing. Tejas is cranked delta.

Cheers....

shiv · Post by **shiv** » 29 May 2009 10:32

neerajb wrote:
The most striking feature why that plane is not Tejas is it's PURE DELTA wing. Tejas is cranked delta.

Cheers....

Absolutely.

In addition, the intakes of the Tejas lie behind and below the wing leading edge while the Mirage intake sticks out in front and has a little central half-cone that sticks out further. This is clearly visible in the doctored picture.

Singha · Post by **Singha** » 29 May 2009 10:49

that mirage half-cone thing move fwd to reduce the air intake size as speeds increase....I believe all a/c that go beyond mach2 need such variable geometry air intakes (mig29, f15, m2k...)

those that dont - like tejas, F18, F-solah seem to be restricted to around mach1.7

shiv · Post by **shiv** » 29 May 2009 10:55

Singha that cone is apparently the simplest version of a supersonic intake where the cone diverts the supersonic shock wave or some such thing. I do not understand how other supersonic intakes work.

Here are some great pics of the LCA's cranked delta and the intakes below and behind the leading edge.

http://www.bharat-rakshak.com/media/Aer ... s.jpg.html
http://www.bharat-rakshak.com/media/Aer ... f.jpg.html
http://www.bharat-rakshak.com/media/Aer ... k.jpg.html

vina · Post by **vina** » 29 May 2009 12:49

that mirage half-cone thing move fwd to reduce the air intake size as speeds increase....I believe all a/c that go beyond mach2 need such variable geometry air intakes (mig29, f15, m2k...)

Yes. The M2K has a translating half cone intake. The best way to think of it is as if the cone in the the nose of the Mig 21 (the inlet for the Mig 21 is in the nose) is split into two and moved to the sides.

The key to understand the physics is that jet engines need inlet air which is subsonic and that includes ram jet engines. So even if the plane is flying supersonically , the intake air has to be slowed down to below the speed of sound so the engines can operate (yeah, scram jet engines work with supersonic airflow, but that is still star trek research world as of now).

So , kinetic energy of the supersonic airflow should be ideally fully converted into potential energy (which manifests itself as high pressure at the engine inlet) and if the conversion is perfect, you should have 100% conversion and should be smooth , cleanly flowing air with no eddies and vortices etc, which will shred the musharraf of the engine.

Problem is, when you slow down supersonic air, there is a normal shock, and there will be huge pressure pressure loss and highly unpredictable airflow.

Now when you put a spike shaped body in the airflow, it gives rise to something called The Mach Cone .Google around for more details. Behind the shock cone, the airflow is subsonic, and outside that is supersonic.

Now that translating spike/cone (in the nose of the Mig 21 or half cones in the M2K), move back and forth depending on air speed and make sure that the shock cone is within the walls of the inlet , and there is an oblique shock , and not a normal shock and the pressure recovery is high and the entire inlet is efficient.

The other kind is the intakes you see in F15, Mig29, Su30 etc, where instead of a translating cone, there are ramp doors in the inlet that move depending on the speed and make sure that there are no normal shocks and the air is slowed down efficiently and pressure recovery is good.

Singha that cone is apparently the simplest version of a supersonic intake where the cone diverts the supersonic shock wave or some such thing. I do not understand how other supersonic intakes work.

The LCA Tejas has a fully shielded inlet that is shielded by the wing. The wing sweep angle lies inside the mach cone for most speeds and the inlet is taking in the subsonic air flow. Beyond a certain speed (the mach cone angle decreases with increase in speed), the mach angle will become less than wing sweep and there will be a shock the wing, the air flow will separate and the inlet may not be really shielded by the wing and there will be big pressure loss in the intake. That I think would put the upper limit on the speed which a fixed inlet (like in Solah, Attarah, Tejas, Rafale, Eurofighter etc) can achieve. That is the trade off. These are really not fleet /high speed interceptors like Padrah and Chaudah require high sprint speed to quickly head into combat zone and for those high mach sprint nos in a straight line is needed.

neerajb · Post by **neerajb** » 29 May 2009 13:01

shiv wrote:Singha that cone is apparently the simplest version of a supersonic intake where the cone diverts the supersonic shock wave or some such thing. I do not understand how other supersonic intakes work.

When any object reaches Mach 1, normal shock wave is formed just ahead of it. It is nothing but highly compressed air which acts as a wall. As the mach number furhter increases, the wall starts to bend towards the object forming a cone of compressed air around the object, something like this ->. The faster you go the narrower the cone becomes.

See the animation at the bottom of the given link : http://selair.selkirk.bc.ca/Training/Ae ... ation.html

At mach 1, the cone (Mig-21) is retracted back position inside the inlet. Now as the Mach number increses, the cone is extended forward so that the oblique shock wave touches the lip of the inlet. See the cone angle differs with Mach number, so the faster you go the further the inlet cone needs to be extended so that the oblique shock wave is always formed at the intake lip, neither outside the intake nor inside it.

Added later : When airflow passes through normal/oblique shock wave, it becomes subsonic. Shock wave is used here as a screen to slow down the speed of airflow into the engine. Subsonic flow is required for the compressor to work efficiently. Compressor is again made up of blades which are airfoils themselves. Like low speed stall we have a high speed stall too that occurs when subsonic airfoils are subjected to supersonic flows. Jet engine's compressors have transonic blading and if they are fed supersonic air, then they will stall, there will be no compression and the engine will most probably surge and flameout. Surges are bad for compressor blades and the engine will need a relight/throttling down if the surge is persistant.

Cheers....

neerajb · Post by **neerajb** » 29 May 2009 15:55

There is another kind of drag that has to do with compressing air molecules in the atmosphere. When flying close to the speed of sound or at the speed of sound (Mach 1), the airflow around an aircraft acts differently than at slower speeds. As the aircraft moves through the air it makes pressure waves. These pressure waves stream out away from the aircraft at the speed of sound. This wave acts just like the ripples through water after a stone is dropped in the middle of a still pond. At Mach 1 or during transonic speed (Mach 0.7 - 0.9), the aircraft actually catches up with its own pressure waves. These pressure waves turn into one big shock wave. It is this shock wave that buffets the airplane. The shock wave also creates high drag on the airplane and slows the airplane's speed. As the airplane passes through the shock wave it is moving faster than the sound it makes. The shock wave forms an invisible cone of sound that stretches out toward the ground. When the shock wave hits the ground it causes a sonic boom that sounds like a loud thunderclap.

http://quest.nasa.gov/aero/planetary/at ... clift.html

Shock wave formation can be described as constructive interferrence of pressure waves in front of the object.

Cheers....

viveks · Post by **viveks** » 29 May 2009 16:33

Good discussion. I always wondered whether those inlets on Tejas could be made angular...much like the ones ...the yanks did with their F-18C ----> F-18E (super hornet).

Gerard · Post by **Gerard** » 30 May 2009 01:23

India readies its light combat aircraft

hnair · Post by **hnair** » 30 May 2009 01:28

Singha wrote:that mirage half-cone thing move fwd to reduce the air intake size as speeds increase....I believe all a/c that go beyond mach2 need such variable geometry air intakes (mig29, f15, m2k...)

Heard the french call them "souris", because they look like mice peering out

SaiK · Post by **SaiK** » 30 May 2009 02:46

hari sud wrote:In the next 20 years, 4,000 combat aircraft of all designs are due for replacement all over the world. The timing is perfect for India’s light combat aircraft, which is currently undergoing trials. It is expected to be inducted into India’s air force in 2010 and available for export five years later. Flying the Indian Air Force’s colors successfully will be a reassurance to future buyers.

its quite important to note this.. where if India plays correct politics and wins its clouts, can establish a fantastic public-private partnership for the production engineering setup of LCA.

LCA for the future, should also enlarge its presence with local component i.e., Kaveri and MMR in subsequent model.

Hari sud's article is great for the intl. market. good job.

ramana · Post by **ramana** » 30 May 2009 02:48

Thanks Hari! Great write up. Hormuz Mama would have approved of it.

Kartik · Post by **Kartik** » 30 May 2009 03:00

pardon me for saying so, but the article is full of inaccuracies..the LCA will not reach Mach 2, even with the newer engine, its composites WILL NOT prevent missiles from locking onto it and saying that the LCA is original while the J-10 is not, and hence will not succeed in the export market is hardly true. you only have to see the export success of the J-7 series to see that the statement is untrue. and while some of the LCA's avionics are to be Israeli, that doesn't mean all of it is, as the author implies.

lets not get carried away by articles that match the BS that Pakis regularly churn out for their domestic consumption. crowing about export success before the LCA is even in IAF squadron service is a little too optimistic as of now.

NRao · Post by **NRao** » 30 May 2009 03:39

And, is the avionics really Israeli?

Some of the avionic hardware components are Israeli, not the software itself. This used to be a oft visited site long back for the LCA.

SaiK · Post by **SaiK** » 30 May 2009 07:26

Kartik, imho, they are very much intended inaccuracies... if you go by the gist of the article, it surely does project the intention for marketing LCA to outside India. There is nothing wrong or BS in the article to say and thrash it. Lets be honest that marketing needs lot of hype, rather reflect BRite thoughts, that chase after "the truth".

If russkies can say, their pakfas can beat the hell outta F22s, then its ok for hari to say what he has said.. /jmt

Singha · Post by **Singha** » 30 May 2009 07:48

the F-15 and F-22 designs are probably the ones most optimized for Mach2+ sprinting.
the wing sweep angle of flanker is less than F-15.

SaiK · Post by **SaiK** » 30 May 2009 08:21

ot/ didn't concord super cruise at mach 2 for thousands of miles? its an old tech!?

saptarishi · Post by **saptarishi** » 03 Jun 2009 18:27

http://www.ada.gov.in/

LCA-Tejas has completed total 1123 test flights

naird · Post by **naird** » 08 Jun 2009 23:27

My first post -- But have been a big time lurker...

Any news about LCA from paanwallah's ?? It seems that everything has gone quiet on LCA front. It was supposed to fly with MMR(or israeli) radar , has that happened ?

p_saggu · Post by **p_saggu** » 09 Jun 2009 00:08

Yes MMR was supposed to be on board. There are allegedly two of them, one on the roof at bangalore and the second on a boeing Hack aircraft in Israel.
Also waiting for PV-5 (the two seater trainer and the precursor to LCA_Navy) to fly.

Isn't LRDE supposed to be working on an AESA specifically for the LCA and other aircraft?

naird · Post by **naird** » 09 Jun 2009 00:52

p_saggu wrote: Isn't LRDE supposed to be working on an AESA specifically for the LCA and other aircraft?

True but then i believe integration of ELTA 2052 (aesa radar) is still being carried out for LCA. This would form as the base of their analysis/studies.

I wish ADA could give a bi weekly status update on their web site for us jingo's instead of just updating the no of test fights...

Anujan · Post by **Anujan** » 09 Jun 2009 01:13

naird wrote:My first post -- But have been a big time lurker...

Any news about LCA from paanwallah's ?? It seems that everything has gone quiet on LCA front. It was supposed to fly with MMR(or israeli) radar , has that happened ?

You are going to hear something about the Kaveri soon.

Vivek K · Post by **Vivek K** » 09 Jun 2009 02:12

Something good?

vipins · Post by **vipins** » 09 Jun 2009 02:32

Anujan wrote: You are going to hear something about the Kaveri soon.

Last news about kaveri was when it was to be send for high altitude testing to moscow.
lets hope its a good news!!

p_saggu · Post by **p_saggu** » 09 Jun 2009 03:09

I don't think LDRE's AESA and Elta's 2052 are the same. I think LDRE's AESA might be an MKIsed 2052 though.

Just like the Embraer AEW&C

SaiK · Post by **SaiK** » 09 Jun 2009 04:14

there is no news yet that its going to be AESA. or was there one that missed? links please?

yossarian · Post by **yossarian** » 09 Jun 2009 04:42

Assuming the LCA is inducted(partially) by 2015, what would it match up against and beat convincingly w.r.t PLAAF and PAF? How long will it be in service and remain competitive against upgrades of match ups in PLAAF and PAF?

I am new and I think I am dumb...I anticipate brickbats, so please feel free.

p_saggu · Post by **p_saggu** » 09 Jun 2009 06:00

SaiK wrote:there is no news yet that its going to be AESA. or was there one that missed? links please?

This was in the scanned Vayu article on the LCA that I think Nayak posted. I'll try and post it. But it definitely said LDRE's developing an AESA for the LCA.

Drevin · Post by **Drevin** » 09 Jun 2009 07:52

hari sud .... nice article. Has all the elements of intrigue and adventure. i also felt pride. Hats off to all those engineers who toiled on the lca .

Vivek K · Post by **Vivek K** » 09 Jun 2009 09:42

200 LCAs on the western border would take care of Pukistan freeing up the flankers for the real fight in the north and the east. LCA can be mated with the sensors and the equipment that IAF wants. And working with the AWACs these aircraft could take care to ensure that PAF fizzles out. We need to urgently get the LCA in squadron service.

K Mehta · Post by **K Mehta** » 09 Jun 2009 11:07

To break the boredom here,
The May 2009 issue of the Journal of aeronautical society of India has beautiful photos of the LCA at weapons testing. The issue isnt online yet, but i will get the scans by next week. The weapons testing was done one more than 2 pylons, and both internal and external pylons were used. Litening pod is also there.
Till then see the older photos of Indian products at the above links. Some nice pics there of some rare beauties.

symontk · Post by **symontk** » 09 Jun 2009 13:02

Just now one LCA was flying around in Green paint, could be a new PV version

narayana · Post by **narayana** » 09 Jun 2009 13:35

symontk wrote:Just now one LCA was flying around in Green paint, could be a new PV version

Is it Cameo Grey Sir? or are you in karachi and would have just watched a JF-17 bandar fly by