LCA News and Discussions

SaiK · Post by **SaiK** » 17 May 2012 22:00

yes.

also, what is that white glue strip on the glass from WSO cam?

Suraj · Post by **Suraj** » 17 May 2012 22:12

The swerve at the point of landing looks like windshear yaw compensation that's fairly normal when the main wheels touchdown. It probably looks much more pronounced from a frontal perspective compared to how it may have been in reality.

karan_mc · Post by **karan_mc** » 17 May 2012 22:13

with landing gear still out , some time it felt like it was trying virtual landing in the sky , made me remember a Discovery documentary on X-31 aircraft

Singha · Post by **Singha** » 17 May 2012 22:14

indeed. youtube is full of way more scary landing with commercial jets.

SaiK · Post by **SaiK** » 17 May 2012 22:59

I think it was a pretty good test for the undercarriage as well.. near hard land as one would land on a/c deck.

Pranay · Post by **Pranay** » 17 May 2012 23:14

suryag wrote:Flight test update

LCA-Tejas has completed 1852 Test Flights successfully. (16-May-2012).
(TD1-233,TD2-305,PV1-242,PV2-222,PV3-343,LSP1-74,LSP2-207,PV5-36,LSP3-51,LSP4-54,LSP5-82,LSP7-2,NP1-1)

from

LCA-Tejas has completed 1849 Test Flights successfully. (12-May-2012).
(TD1-233,TD2-305,PV1-242,PV2-222,PV3-342,LSP1-74,LSP2-207,PV5-36,LSP3-50,LSP4-53,LSP5-82,LSP7-2,NP1-1)

NP1 video is fantastic. Btw during landing the aircraft seems to experience a cross wind

suryag - Thanks for the regular updates on the LCA flights - Do highlight the PV3 in addition to the LSP3 and LSP4 - all three went up by one.

merlin · Post by **merlin** » 18 May 2012 09:56

sameer_shelavale wrote:
Roperia wrote:NP 1 First Flight video has been posted at http://www.tejas.gov.in/
Video URL NP 1: First Flight: 27th April 201
it says

Access to this site has been blocked as per Court Orders

Can see that from Reliance connection. Maybe blocked from Airtel and/or BSNL.

jamwal · Post by **jamwal** » 18 May 2012 10:34

Morons in Reliance have obtained a 'John Doe' court order from equally ignorant judiciary with which they have forced many ISPs to block file sharing sites and some video sites like Vimeo. If you are facing any such problem with your internet connection, you know who to lynch.

Roperia · Post by **Roperia** » 18 May 2012 12:16

For folks who couldn't see it on vimeo, you may now watch it on youtube. Our PSUs are getting better at PR.

MN Kumar · Post by **MN Kumar** » 18 May 2012 15:50

Saw a pair of LCA's this morning in formation.

Kartik · Post by **Kartik** » 19 May 2012 00:05

SaiK wrote:yes.

also, what is that white glue strip on the glass from WSO cam?

my guess is that its embedded explosive cord to shatter the canopy if the pilot needs to eject.

Indranil · Post by **Indranil** » 19 May 2012 04:50

hmmm .... interesting .. that strip has always been there on LCA and IJT. Never noticed it before.

shiv · Post by **shiv** » 19 May 2012 07:20

I just wonder if it is merely a "reference strip" for the onboard cockpit camera to be used along with video footage to assess control inputs during takeoff and landing? For example that yaw (possibly due to crosswind) when the nosewheel touched the ground can be measured using deviation from centre line of runway and compared with any control inputs that were initiated at the time? Just a guess

Indranil · Post by **Indranil** » 19 May 2012 08:07

shiv wrote:I just wonder if it is merely a "reference strip" for the onboard cockpit camera to be used along with video footage to assess control inputs during takeoff and landing? For example that yaw (possibly due to crosswind) when the nosewheel touched the ground can be measured using deviation from centre line of runway and compared with any control inputs that were initiated at the time? Just a guess

No Shivji, you can see it in all LCAs (even single seaters) and IJTs. In this picture, you can see the explosive cord clearly. Notice that it is not at the center. Also notice that it is not at the center. It is slightly to the right side. When the canop would be closed it would line up nicely on top of the "shell tooth" on top the pilot seat to break the glass. Looks like HAL birds are going to use the Through-Canopy Penetration like on the A-10 Thunderbolt II.

I had not noticed this feature before. But it makes sense now.

pragnya · Post by **pragnya** » 19 May 2012 08:15

Kartik wrote:
SaiK wrote:yes.

also, what is that white glue strip on the glass from WSO cam?
my guess is that its embedded explosive cord to shatter the canopy if the pilot needs to eject.

kartik, is this what you are referring to??

Canopy Severance System for fighter air craft

The Canopy Severance System (CSS) of a fighter aircraft is life saving device that helps in safe ejection of a pilot in distress. Two critical components required for functioning of CSS, MDC for cutting canopy bubble and Explosive transfer line (ETL) for transmission of explosive shock from one point to another without affecting surroundings were developed and their production methods established. MDC and ETL function with a velocity of detonation of 6000 m/s ensuring that the cutting action of the Canopy occurs in less than 5 m sec from the time of initiation. Afterthe successful development of this system, the import option of CSS for LCA by ADA was dropped. LCA TD-1,TD-2 and PV-1 have been assembled with indigenous CSS. An upgraded system developed for HJT-36, a trainer aircraft, after successful evaluation has been assembled on the first prototype of HJT-36 that has been in flight since February 2003.

Kartik · Post by **Kartik** » 19 May 2012 10:31

pragnya wrote:
kartik, is this what you are referring to??

Canopy Severance System for fighter air craft

The Canopy Severance System (CSS) of a fighter aircraft is life saving device that helps in safe ejection of a pilot in distress. Two critical components required for functioning of CSS, MDC for cutting canopy bubble and Explosive transfer line (ETL) for transmission of explosive shock from one point to another without affecting surroundings were developed and their production methods established. MDC and ETL function with a velocity of detonation of 6000 m/s ensuring that the cutting action of the Canopy occurs in less than 5 m sec from the time of initiation. Afterthe successful development of this system, the import option of CSS for LCA by ADA was dropped. LCA TD-1,TD-2 and PV-1 have been assembled with indigenous CSS. An upgraded system developed for HJT-36, a trainer aircraft, after successful evaluation has been assembled on the first prototype of HJT-36 that has been in flight since February 2003.

Yes Pragnya. the ETL most likely is the white explosive cord seen in the canopy..now I'm not sure whether it's embedded or glued using special adhesives on to the canopy after it is produced. My guess now is that its actually glued using adhesive rather than embedding it while producing the canopy, which may be a trickier proposition.

This excellent document which is an old report I found on the net, describes how such a centerline severence system will work on a fighter. On page 132 of this report, you'll find a Concept D "Centerline Severance with Seat Mounted Parting Structure". the LCA's canopy severance system may correspond to something similar. Page 134 explains that a bonding joint of the centerline charge is feasible and only thing that needs to be accounted for is a possible loosening or separation of the centerline charge due to a bird strike that may result in shock waves emanating through the canopy. But ARDE guys would've taken this into account while choosing the adhesive and the retainer material for the centerline charge.

pragnya · Post by **pragnya** » 19 May 2012 11:16

Kartik wrote:Yes Pragnya. the ETL most likely is the white explosive cord seen in the canopy..now I'm not sure whether it's embedded or glued using special adhesives on to the canopy after it is produced. My guess now is that its actually glued using adhesive rather than embedding it while producing the canopy, which may be a trickier proposition.

This excellent document which is an old report I found on the net, describes how such a centerline severence system will work on a fighter. On page 132 of this report, you'll find a Concept D "Centerline Severance with Seat Mounted Parting Structure". the LCA's canopy severance system may correspond to something similar. Page 134 explains that a bonding joint of the centerline charge is feasible and only thing that needs to be accounted for is a possible loosening or separation of the centerline charge due to a bird strike that may result in shock waves emanating through the canopy. But ARDE guys would've taken this into account while choosing the adhesive and the retainer material for the centerline charge.

thanks kartik for that document. will go thro' it. just downloaded it.

pragnya · Post by **pragnya** » 19 May 2012 12:02

Kartik wrote: Yes Pragnya. the ETL most likely is the white explosive cord seen in the canopy..now I'm not sure whether it's embedded or glued using special adhesives on to the canopy after it is produced. My guess now is that its actually glued using adhesive rather than embedding it while producing the canopy, which may be a trickier proposition.

i think you are right as noted in this article -

"The initiator generates a detonation wave which is transmitted in a totally contained manner to a line charger pasted along the canopy and thus cutting it peripherally. This helps in rescuing the pilot," he explained.

ARDE develops safe ejector system for LCA

ramana · Post by **ramana** » 21 May 2012 20:54

The ETL transmits the detonation wave to initiate the line charge pasted along the canopy. There are two charges: the ETL and the line charge. I wonder if line charge is a shaped one for cutting the canopy.

SaiK · Post by **SaiK** » 21 May 2012 21:37

Let us assume the fully canopy does not break up by the explosion? would that mean the ejection would not work? so, is it not all these happen on one single push ejection button? or is this something that pilot does after the ejection single push button fails to eject, and he goes for the explosion of the canopy?.. and if he is lucky and has time to wriggle out of the shattered opening and does a para jump.

Lalmohan · Post by **Lalmohan** » 21 May 2012 22:27

the canopy is meant to shatter miliseconds before the top of the ejection seat pushes through the perspex and the pilot theoretically flys through unscathed. if it doesnt shatter, it is unlikely that the pilot will survive the ejection

Cain Marko · Post by **Cain Marko** » 22 May 2012 01:06

^ As in the case of "Goose" in Top Gun? Here the canopy flies off though - no shattering:

Or is this all hollywood BS?

Rahul M · Post by **Rahul M** » 22 May 2012 01:11

IIRC side opening canopies are supposed to shatter, the ones hinged at back are blown off.

SaiK · Post by **SaiK** » 22 May 2012 03:12

intersting, so there lies the natural design decision. hinged at back looks natural to be blown off {meaning not explosion but wind blown off}.. all it takes is a button to release the hinge.. still the risk remains, that what if the hinge does not give away?

so, there could be a logical thinking in shattering the glass. For the future, I am imagining the cockpit itself is an LRU along with the human inside (future if).. so that, they eject off the fuselage assembly in one piece.. need huger chute.. but it could be all kevlar, and only important data devices along with him having the mission data, and ciritical survival pack. The whole LRU connects on quadriple fail-op redundant connectors, and latches.

again, the risk remains, on the what if scenarios.

CM, that is nicely done Hollywood BS.. cause the ejection seat event is atleast 1/2sec after the canopy release.. so, how could the pilot eject into the canopy straight up ?

and the real scenario need not be that the jet is travelling in a straight line.

Philip · Post by **Philip** » 22 May 2012 04:50

Look,is the answer given to the House (in the BR news) reality or a pipe dream,about there being 6 LCA sqds. by 2020 (13th plan).This means that within the next 7 years ,we will be producing about 120 aircraft,at least 100,if the first sqd. is commissioned by early 2013,at the rate of about 14-15 a year.The last time an official statement was made the rate mentioned was around 8 per year to start with.

Secondly,when MK-2 (which the IAF wants) with a more powerful engine has yet to fly,with considerable design changes to the fuselage we are told to accommodate a larger engine,and a few years of flight testing after that,when will MK-2 be certified and how will we be able to ramp up production so quickly? These statements made in the House seem to be the usual babu replies meant to fool the nation,which we see trotted out time and time again.Yet again there seems to be no questioning of these statements by any MP.Are they so disinterested in the nation's security?

If we compile a list of official statements/dates that have been made about the LCA and Kaveri,which have never been met,it might end up being quite a fat little booklet !

Kartik · Post by **Kartik** » 22 May 2012 05:50

SaiK wrote:intersting, so there lies the natural design decision. hinged at back looks natural to be blown off {meaning not explosion but wind blown off}.. all it takes is a button to release the hinge.. still the risk remains, that what if the hinge does not give away?

its not so simple. what if you eject from zero/zero position? There will be no wind to push the canopy backwards.

so, there could be a logical thinking in shattering the glass. For the future, I am imagining the cockpit itself is an LRU along with the human inside (future if).. so that, they eject off the fuselage assembly in one piece.. need huger chute.. but it could be all kevlar, and only important data devices along with him having the mission data, and ciritical survival pack. The whole LRU connects on quadriple fail-op redundant connectors, and latches.

It has been done in the past. the F-111 had side by side seating and the entire cockpit section would eject if the pilots needed to escape and parachute down like the escape module of a space craft. There is no specific benefit from having the entire cockpit eject, so why would this be a requirement from future aircraft?

SaiK · Post by **SaiK** » 22 May 2012 06:44

I was thinking on the scenarios, when the pilot would be landing on enemy side. so, what basic things needed could be packaged - some minimal weapon system, med kits, communication equipments, etc.. may be it is not required, if all these can packaged as wearable systems. sometimes, stories are better told by technolgy, if the package includes them to copy important mission data before expunge.

shiv · Post by **shiv** » 22 May 2012 07:15

Folks I am no expert, but I seriously doubt if a strip of explosive will be pasted right above the pilot's head. I don't think cockpit canopies are designed to shatter into a million fragments upon cracking like car wind shields. They are designed to maintain their integrity despite damage. I would have thought that the logical place to put such a strip of explosive is along the sides of the canopy near where it is attacked to the fuselage. The explosive strip must blow and detach the canopy all around so it flies off in one piece, or even if it does not fly off - it is loose so that the seat itself can lift it off as the seat ejects.

I am personally not convinced that blowing a longitudinal hole above the pilot's head is of any real use. In fact the logical thing to do would be to blow a circular/oval hole with a large circular or oval strip of explosive. But that is the same as pasting explosive along the edges of the canopy. I might be wrong but I need to see more convincing accounts of why I am wrong and that the white strip is actually explosive.

Singha · Post by **Singha** » 22 May 2012 07:52

the white strip is fairly common and seen in many canopies. if you leave the canopy intact and expect it to fly away, chances are it wont and the ejection seat and pilots head will hit it on the way up. iirc this happened in top gun to "goose" as he tried to eject from the plane going down (flat spin). breaking it open in clamshell fashion ensures better chances for the ejection seat to make it clear with no obstruction.

member_20067 · Post by **member_20067** » 22 May 2012 08:15

shiv · Post by **shiv** » 22 May 2012 08:31

Singha wrote:the white strip is fairly common and seen in many canopies. if you leave the canopy intact and expect it to fly away, chances are it wont and the ejection seat and pilots head will hit it on the way up. iirc this happened in top gun to "goose" as he tried to eject from the plane going down (flat spin). breaking it open in clamshell fashion ensures better chances for the ejection seat to make it clear with no obstruction.

No. The pilots head is not supposed to hit the canopy and the canopy is not supposed sit there. The canopy should normally be blown off by a regular explosive charge as part of the ejection sequence. But even if it fails to blow off, the canopy should get easily lifted away by the top of the pilots headrest or some other "punching" mechanism. Not the pilots head. That easy lifting away cannot occur if the regular canopy release fails. Hence the extra safety precaution of explosive strip to shatter the material of the canopy itself.

The explosive strip we are talking about is only an additional precaution to make a clean break of the canopy material itself in case the canopy fails to blow off. There is nothing in the news item about the LCA's new canopy blowing system that suggests that the explosive strip is pasted above the pilots head. I think two unrelated things are being connected up in this discussion. The speculation is that the white strip in the NLCA video is an explosive strip.

I do not believe that yet. I am looking for better proof that the "new system for blowing off the LCA canopy"==white explosive strip above pilots head. Canopies do not shatter but can be "clean cut" by an explosive strip. What is the use of making a clean cut above the pilots head if that head is going to get crushed for not being able to pass through a clean narrow cut in the canopy above his head? Unless the clean cut is further shattered by a punching mechanism fixed to the top of the headrest above the pilot's head?

rajanb · Post by **rajanb** » 22 May 2012 08:39

I remember when I was sitting in the cockpit of a MiG-21 during the early 80s I was stunned by the a/c being overwhelmingly populated by wester avionics. The discussion, therefore shifted to the pilot's seat which was Ru.

The cockpit did not have a strip. The engineer explained to me that there were 10 small explosive cartridges embedded in the aircraft to explode in sequence. The first one was the canopy cartridge.

More details in http://www.topedge.com/panels/aircraft/ ... ft/km1.htm for the MiG 21

However, now they do put a line charged explosive:

Escape systems
ARDE have developed ejection seat for LCA HAL Tejas military aircraft. The British Martin-Baker ejection seat used for initial prototype is planned to be replaced with a locally-developed alternative. To improve pilot safety during ejection, the Armament Research and Development Establishment (ARDE), Pune, India created a new line-charged canopy severance system, which has been certified by Martin-Baker.

from http://en.wikipedia.org/wiki/Armament_R ... ablishment

Cheers

shiv · Post by **shiv** » 22 May 2012 08:41

http://drdo.gov.in/drdo/images/he1.ht2.jpg
http://drdo.gov.in/drdo/images/he1.ht3.jpg

These two images (linked inline above) show what i am talking about.

In the upper image the pilot's helmet has hit the canopy. That would kill the pilot. In the lower image the canopy has been blow clean off at the edges on the sides near where the canopy is attached to the fuselage. And the pilot's head has not moved up yet. Note ramana's point about the charge causing a 6000 mps directed explosion to cut and not shatter. Note also that the canopy has not shattered and disintegrated in the earlier photo despite the helmet causing a break. Neither has it shattered in the second - but there is a clean cut canopy along the line near where it is attached to the metal canopy frame.

I can see no evidence that a centerline separation system has been designed and that the white strip is a centerline explosive strip. I am calling that speculation.

Kartik · Post by **Kartik** » 22 May 2012 08:43

shiv wrote:Folks I am no expert, but I seriously doubt if a strip of explosive will be pasted right above the pilot's head. I don't think cockpit canopies are designed to shatter into a million fragments upon cracking like car wind shields. They are designed to maintain their integrity despite damage. I would have thought that the logical place to put such a strip of explosive is along the sides of the canopy near where it is attacked to the fuselage. The explosive strip must blow and detach the canopy all around so it flies off in one piece, or even if it does not fly off - it is loose so that the seat itself can lift it off as the seat ejects.

I am personally not convinced that blowing a longitudinal hole above the pilot's head is of any real use. In fact the logical thing to do would be to blow a circular/oval hole with a large circular or oval strip of explosive. But that is the same as pasting explosive along the edges of the canopy. I might be wrong but I need to see more convincing accounts of why I am wrong and that the white strip is actually explosive.

Shivji, did you read the paper that I posted in an earlier post? It is one of the concepts that is discussed. Besides, how is it different to paste adhesives on the sides of the pilot as far as danger goes?

read this thread as well if you like. the Tornado, Harrier, Hawk, etc. all have explosive cord over the pilot's head. On the Tornado, it does seem to be adhesively attached to the canopy

Kartik · Post by **Kartik** » 22 May 2012 08:47

shiv wrote:

http://drdo.gov.in/drdo/images/he1.ht2.jpg
http://drdo.gov.in/drdo/images/he1.ht3.jpg
These two images (linked inline above) show what i am talking about.

In the upper image the pilot's helmet has hit the canopy. That would kill the pilot. In the lower image the canopy has been blow clean off at the edges on the sides near where the canopy is attached to the fuselage. And the pilot's head has not moved up yet.

How do you know that for sure? You don't know what the forces acting on the pilots head in that picture were. It might well have been that the glass had been shattered before the pilot's head contacts it, in which case the pilot may not suffer any injuries since he's wearing a helmet.

shiv · Post by **shiv** » 22 May 2012 08:52

Kartik wrote:
Shivji, did you read the paper that I posted in an earlier post? It is one of the concepts that is discussed. Besides, how is it different to paste adhesives on the sides of the pilot as far as danger goes?

It's not about the danger from the explosion. It is about what happens after the exploive strip does its job. If the explosive strip makes a clean cut above the pilot's head there will be a letter box type slit hole that will have to be further shattered by something - usually the pilot's headrest. It is feasible. I am not saying that it is impossible.

All I am saying is that as far as I can tell, the choice made for the LCA is probably (probably) an explosive strip that separates the canopy along the sides and I think that that calling that white strip in that video as the explosive strip is speculation. I will believe it if I find some more information. I currently do not believe it. Those photos above are clinchers. In the first the pilots helmet has hammered off the canopy. That would kill anyone. In the second the canopy is clean cut long before the pilot's head has risen

A pilots head cannot go though a slit. That centerline slit will need some additional mechanism to shatter it further. No such thing is required if the canopy is severed by a strip places all around at the edges as in photo 2.

shiv · Post by **shiv** » 22 May 2012 08:56

Kartik wrote: How do you know that for sure? You don't know what the forces acting on the pilots head in that picture were. It might well have been that the glass had been shattered before the pilot's head contacts it, in which case the pilot may not suffer any injuries since he's wearing a helmet.

As much speculation on my part as calling a centerline strip as explosive. But note that the shattered canopy above the pilot has ragged edges in photo 1 and looks like an unclean break totally unlike what one would expect from a strip of high explosive. Also there is no centerline break. The second photo shows a clean cut of the canopy as would be expected from a sudden sharp explosion.

shiv · Post by **shiv** » 22 May 2012 08:58

Kartik wrote:
read this thread as well if you like. the Tornado, Harrier, Hawk, etc. all have explosive cord over the pilot's head. On the Tornado, it does seem to be adhesively attached to the canopy

http://webarchive.nationalarchives.gov. ... 135_f3.jpg

I am not disputing that this is done. I am disputing the idea that the incomplete strip above the NLCA pilots head is the same as this complete strip seen in the photo you have linked.

Kartik · Post by **Kartik** » 22 May 2012 09:00

shiv wrote:
Kartik wrote:
Shivji, did you read the paper that I posted in an earlier post? It is one of the concepts that is discussed. Besides, how is it different to paste adhesives on the sides of the pilot as far as danger goes?

It's not about the danger from the explosion. It is about what happens after the exploive strip does its job. If the explosive strip makes a clean cut above the pilot's head there will be a letter box type slit hole that will have to be further shattered by something - usually the pilot's headrest. It is feasible. I am not saying that it is impossible.

All I am saying is that as far as I can tell, the choice made for the LCA is probably (probably) an explosive strip that separates the canopy along the sides and I think that that calling that white strip in that video as the explosive strip is speculation. I will believe it if I find some more information. I currently do not believe it. Those photos above are clinchers. In the first the pilots helmet has hammered off the canopy. That would kill anyone. In the second the canopy is clean cut long before the pilot's head has risen

A pilots head cannot go though a slit. That centerline slit will need some additional mechanism to shatter it further. No such thing is required if the canopy is severed by a strip places all around at the edges as in photo 2.

the idea is not to try to slide the pilot's head through the slit over his head created by the explosion. The explosives on the sides of the pilot and on top of the pilot basically ensure that the canopy will open itself up like a clamshell when the pilot is about to eject. Nobody said that there is no other explosive except the one over the pilot's head. There are explosive linings on the side of the canopy as well.

shiv · Post by **shiv** » 22 May 2012 09:08

I am guessing that in a large, heavy canopy a centerline explosive strip would have to continue down the sides near the canopy frame so that the canopy is "cut" into two clean clamshell halves. The tornado in the pic above looks like it might have that. But then why is the strip incomplete in the NLCA?