LCA News and Discussions

Katare · Post by **Katare** » 13 Jul 2012 09:34

Never heard or seen anyone sleeping at work or anyone approving it until today! Well it's BRF, everyday you learn something here!

Singha · Post by **Singha** » 13 Jul 2012 09:36

cool looking kit. all it needs is a ipod dock.

Kartik · Post by **Kartik** » 13 Jul 2012 09:56

avinashpeter wrote:

Please also take note of the Aircraft in picture at HALBIT counter... It shows again the speculated Mk3..

For the third time in 2 pages, THAT IS NOT THE TEJAS MK3 !! There is no speculation on this since it is not yet on the drawing board !

Sid · Post by **Sid** » 13 Jul 2012 10:20

Singha wrote:cool looking kit. all it needs is a ipod dock.

Naah.. it just needs iOS/Andriod.

Buy apps over the air (literally) while you are bombing enemy a$$ and watch Netflix on your way back home.

Vivek K · Post by **Vivek K** » 13 Jul 2012 11:07

Katare wrote:Never heard or seen anyone sleeping at work or anyone approving it until today! Well it's BRF, everyday you learn something here!

+1

Neela · Post by **Neela** » 13 Jul 2012 13:39

About 4 years ago , my boss was at a subsidiary unit in China giving a training session. Post lunch , he comes back to the room and finds the entire bunch of 8 people sitting on the desks and sleeping with heads on the table. It took a good 30 minutes before they woke up. pl. note, I said China and not a specific city. And they did not care what others thought.
In Spain and warmer parts of Italy , an afternoon siesta is very normal. Pl note - I said Spain and not a specific city.

I do not know why this is a big deal.
I have had my horrible weeks and have slept at my desk in the afternoon for 10 minutes.

Being opinionated is one thing. Self flagellation AND opinionated AND judgmental -

karan_mc · Post by **karan_mc** » 13 Jul 2012 14:31

So that poor speculative drawing of AMCA was from HALBIT Counter

, any way it is not Tejas MK-3 , you can spot Twin tail fin on the plane , it is poor drawings of AMCA and i am dam sure about it

SaiK · Post by **SaiK** » 13 Jul 2012 17:03

well it is much better than weird looking hand drawn LCA that was floated some eons back.

Gus · Post by **Gus** » 13 Jul 2012 18:50

Katare wrote:Never heard or seen anyone sleeping at work or anyone approving it until today! Well it's BRF, everyday you learn something here!

huh..back in my old auto company, many engrs doze off for a few mins. Even those who run the plant hands on. These people are not slackers. They work their butt off.

In ITVity, I used to doze off for 15 to 20 mins after lunch. I would walk down, find a shady tree and sleep on the grass with my shoes as pillows. Many times the client VP, program manager, my client peers and my own colleagues walk by and it was all cool. Not an eyebrow raised.

suryag · Post by **suryag** » 13 Jul 2012 19:21

Taking a half hour nap is entirely fine in China, encountered this in their Huawei office and the lights were also dimmed. Anyways i think all of this is OT

Hope I dont go to Hakim garu for surgery just after his lunch, he might cut off mijjile instead of something else while he is dozing after lunch

Hakim garu sorry about the bad humour couldnt resist

Meanwhile
Flight test update

LCA-Tejas has completed 1937 Test Flights successfully. (12-July-2012).
(TD1-233,TD2-305,PV1-242,PV2-222,PV3-348,LSP1-74,LSP2-237,PV5-36,LSP3-73,LSP4-56,LSP5-103,LSP7-4,NP1-4)

from

LCA-Tejas has completed 1932 Test Flights successfully. (09-July-2012).
(TD1-233,TD2-305,PV1-242,PV2-222,PV3-348,LSP1-74,LSP2-234,PV5-36,LSP3-73,LSP4-56,LSP5-101,LSP7-4,NP1-4)

member_23626 · Post by **member_23626** » 13 Jul 2012 19:40

Ummm.. why are moaning about an alleged design of Mk.3 that hasn't even been mentioned by any defence org. (nor any other doofuses like shiv error)... Let's get back on the topic and leave all other hoopla aside... Btw does anyone know how Mk.2 looks like? I haven't found a reliable design yet...

SaiK · Post by **SaiK** » 13 Jul 2012 20:00

there is a build your own a/c thread, where lca mk3 can be discussed.

Singha · Post by **Singha** » 13 Jul 2012 21:30

some huawei engineers in shenzhen have a quick 15 min lunch and then sleep 45 mins below their desk before a bell rings to wake the troops. this per a indic huawei guy who spent some months there.

A Sharma · Post by **A Sharma** » 13 Jul 2012 22:26

20th Anniversary Celebrations of the National Control Law Team

National Control law team of LCA is a very unique team formed in 1992. The team is the result of a truly great visionary Dr APJ Abdul Kalam the then SA to RM. The team took up the challenge of building fly-by-wire control laws for an unstable fighter aircraft for the first time in India. This talented and enthusiastic team celebrated its 20th Anniversary on 2nd June 2012 in Dr. Valluri Auditorium, National Aerospace Laboratories.

The celebrations started with an invocation by Dr. Girija Gopalaratnam, Acting Head, Flight Mechanics and Control Division. Mr. Shyam Chetty, Acting Director, NAL, extended a warm welcome on behalf of CSIR-NAL and National Control Law Team to all the invitees from DRDO, ADA, HAL and CSIR-NAL for this memorable day. He narrated the circumstances that had led to the formation of the National Control Law Team. A global tender was floated in the early 1992 seeking consultancy support from reputed airframe houses abroad for the design and development of fly-by-wire control laws for LCA. When no favorable response was received, Dr. Kalam immediately formed an empowered committee headed by late Prof. I G Sharma of School of Automation -IISC, Dr. Vidyasagar the then Director, CAIR-DRDO and many others to scout for suitable talent across various IITs, IISc, R&D institutions and Public Sector units. Since it was very clear that no single institution in India could claim to have required strength, experience / expertise to carry out this highly complex, safety critical and multi disciplinary task. This talent search lead to the formation of National Control Law Team very popularly known as CLAW Team at CSIR-NAL, with Dr. S Srinathkumar as founder Project Director. Initially team members were drawn from CSIR-NAL, CAIR and ADA along with one test pilot Wg. Cdr. BB Misra from IAF.

Mr. Shyam Chetty informed that first flight of LCA took place on 4th January 2001 and said that 9 years had elapsed from the time the team was formed. He justified the time taken for this task by comparing it with similar programs in the world. Mr. Shyam Chetty mentioned that over 1900 successful flights on 13 prototypes including the 2 seater trainer and naval variant have been flown by 19 IAF pilots and all of them are very appreciative of the performance of the flight control system and control laws including flying qualities and the ease with which the aircraft handled. Mr. Shyam Chetty emphasised that the LCA program has reached an important milestone in achieving Initial Operation Clearance (IOC) as this will enable the IAF’s squadron pilots to fly TEJAS. He also reminded that the team still had some distance to go before the aircraft got its Final Operation Clearance (FOC). He concluded his address by saying that the expertise and experience gained by the team over the years in this niche strategic area has been shared and found useful by all other major national aerospace programmes.

Prof. Samir K Brahmachari, DG-SCIR graced the occasion as the chief guest. In his address, he quoted that, “very often we say, we can’t do things together and when people do things together, we say because they can’t do it alone”. Therefore, it needed no less than Dr. Kalam the visionary to mobilize this team. He said, NAL is very important for CSIR, and Aeronautics Research is very important for the country. Therefore, he visited NAL many times since he had taken over as DG-CSIR to encourage the team NAL. He mentioned that he was glad to see Dr. Mashelkar’s vision of a CSIR civil aircraft flying in Indian skies had been taken up by NAL. Prof. Samir K Brahmachari stated that such celebrations allows us to go back in years, sit and think under what circumstances these collaborations were built, and also allows us to think about new collaborations that need to be built so that they can be celebrated 20 years from now. He informed the august audience about the CSIR’s vision document and the paradigm shifts that CSIR has initiated to build a new CSIR. He suggested DRDO / ADA / NAL management to earmark part of the project funds to address futuristic projects and dedicate a team of youngsters who will think differently on realizing futuristic aeronautical needs of the country. He again reiterated CSIR’s commitment to partner the strategic sector organisations in meeting the nation’s requirements. He stated that CSIR-NAL should continue to take the initiative in conducting cutting edge research in Aerospace Science and Engineering of tomorrow.

On this momentous occasion, DG-CSIR handed over a CD containing the IOC version of the Control Laws and Airdata Algorithms to AVM RKS Bhadauria, ACAS (Projects) and to Mr. P S Subramanyam, Director ADA. Air Marshal R K Sharma, DCAS who had initially promised to be part of the celebrations has instead sent a message. The message reads, “I sincerely appreciate the efforts of CSIR-NAL and congratulate them for reaching the important (IOC) milestone. You and your team have done an outstanding job over the years, working with scientific diligence and above all confidence tempered with humility. I would like you to know that every time I flew the LCA, I knew, that the CLAW which is the heart of the system, is robust and will not fail, that belief alone made me fly confidently. I believe that is a sentiment shared by the other LCA Test Pilot’s as well. I wish I could have made it to the function, sadly, I can’t”.

AVM RKS Bhadauria, in his remarks said that it was a momentous occasion because of the IOC – CD that he had received. He mentioned that the IOC-CD he was holding could be the most valuable CD in the country. He remembered that as a test pilot of Tejas, he had close interactions with the team and had a great confidence in the team. He mentioned that CLAW was never an issue in the planning of flight testing. He stated that to the best of his knowledge TEJAS was the only fly-by-wire fighter aircraft in the world that had test flown over 1900 sorties without even a single major problem. He also appreciated that the team had contributed in many other areas apart from CLAW such as Notch filter design, PID and so on. He concluded his speech by asking the team to continue in the same manner in future.

Mr. P.S. Subramanyam, Director ADA in his remarks informed the audience that, he had started interactions with the CLAW team as Project Director, IFCS-LCA. He recollected that right from the beginning the team had met all the deliverables on time without any delay. He appreciated that the team had never compromised on safety even under tremendous pressures from program management and the outcome of this commitment was the robust and fault free control laws. He was confident that the team would continue the work with the same commitment in the future. Apart from designing the control laws, he said the team had contributed a lot to TEJAS. He remembered the participation and significant contributions of the CLAW team in clearance activities at Iron-Bird. He said the team showed the same level of commitment and help in designing and clearing the robust redundancy management algorithm of FCS. He also acknowledged the outstanding contributions of the team in the area of simulation and modelling.

During the celebrations, the National Control Law Team showcased the achievements of CLAW through a small technical session. Two presentations were made in this session by CLAW team members. Dr Abhay Pashilkar, Scientist, NAL made a presentation on “Modelling and Simulation activities of Tejas”. In his presentation, Dr. Pashilkar brought out the flight dynamic analysis of an unstable aircraft, aircraft simulation including subsystems modeling and also explained the challenges faced in the complex modelling of aircraft wake. Later Dr. Vijay V Patel, Scientist, ADA made a presentation on “Design and Development of Flight Control Laws for LCA”. In his presentation, Dr. Patel outlined various activities of the CLAW team. He highlighted the complexities of this airframe such as local pitch up, leading to small time to double, large variation in centre of gravity and many more issues that posed interesting problems to the designers.

In his presidential address, Dr. Kota Harinarayana former Program Director-LCA stated that National Control Law Team is “a jewel in the crown of the LCA program”. He said, CLAW apart from Stability Augmentation provided predictable Handling Qualities, Carefree & Boundary Limiting features leading to Safe operations and served as an ideal weapon system platform. CLAW is a crucial link between the airframe and the pilot. He brought to the notice of the audience that CLAW technology is in the prohibited list of US and other advanced nations. National Control law Team under able leadership of Dr. S Srinathkumar and subsequently Mr. Shyam Chetty ably assisted by Dr. Girish Deodare and team demonstrated high standards of competence, professionalism, team spirit, dedication and modesty. They had delivered a product that continues to receive accolades from all experts in aerospace engineering and from all the pilots who have flown LCA. He remembered his interactions with US pilots during IFS testing and quoted one of the F16 pilot’s statement “F16 airframe flies better with LCA control laws”. He concluded his speech by hoping the team would grow in numbers so that it could to contribute for many other national programs.

As part of the celebrations, the team felicitated the dignitaries in the audience who directly or indirectly contributed to the National Control law Team’s success by presenting mementos. Dr. S Srinathkumar, founder project director – CLAW, Dr. T S Prahlad, Former Director –NAL, Airmarshal Rajkumar (Retd), Mr. G Elengovan – CC R&D (Aeronautics and Avionics), DRDO and many other dignitaries were present at the function. Mr. P V S Murthy, Scientist, NAL & Member of CLAW team gave the formal vote of thanks. He thanked all the dignitaries on and off the dias and all the invitees for their august presence at the function. The entire celebrations were compered in style by Dr. Amitab Saraf, Scientist, ADA along with Dr. Jatinder Singh, Scientist, NAL.

On the same day, immediately after the function, DG – CSIR inaugurated the new “Centre of Excellence in Flight Mechanics & Control” building, built adjacent to the Systems Building of National Aerospace Laboratories. The building hosts modern facilities including the Augmented Engineering Environment (AEE) and Micro Air Vehicle (MAV) Laboratory.

Vivek K · Post by **Vivek K** » 13 Jul 2012 22:38

Singha wrote:some huawei engineers in shenzhen have a quick 15 min lunch and then sleep 45 mins below their desk before a bell rings to wake the troops. this per a indic huawei guy who spent some months there.

So are you saying it is ok to sleep during your "lunch break" or is the BRF's new normal that taking a nap during your "work hour" (not lunh break) is A-OK?

member_23626 · Post by **member_23626** » 13 Jul 2012 22:43

Vivek K wrote:
Singha wrote:some huawei engineers in shenzhen have a quick 15 min lunch and then sleep 45 mins below their desk before a bell rings to wake the troops. this per a indic huawei guy who spent some months there.
So are you saying it is ok to sleep during your "lunch break" or is the BRF's new normal that taking a nap during your "work hour" (not lunh break) is A-OK?

can we stop this now? Stop derailing the thread

Kartik · Post by **Kartik** » 13 Jul 2012 23:48

Neela wrote:About 4 years ago , my boss was at a subsidiary unit in China giving a training session. Post lunch , he comes back to the room and finds the entire bunch of 8 people sitting on the desks and sleeping with heads on the table. It took a good 30 minutes before they woke up. pl. note, I said China and not a specific city. And they did not care what others thought.
In Spain and warmer parts of Italy , an afternoon siesta is very normal. Pl note - I said Spain and not a specific city.

I do not know why this is a big deal.
I have had my horrible weeks and have slept at my desk in the afternoon for 10 minutes.

Being opinionated is one thing. Self flagellation AND opinionated AND judgmental -

I've heard of things that are unheard of in the US or India- having beer or wine during lunch breaks. This happens quite frequently in Germany where a few of my colleagues have worked. They say that its not at all frowned upon for a guy to have a couple of beers at lunch and then come back to work. In the US, most engineering companies would fire someone for such a thing.

Perceptions of what is right or wrong differ in each country.

member_23626 · Post by **member_23626** » 13 Jul 2012 23:53

Neela wrote:About 4 years ago , my boss was at a subsidiary unit in China giving a training session. Post lunch , he comes back to the room and finds the entire bunch of 8 people sitting on the desks and sleeping with heads on the table. It took a good 30 minutes before they woke up. pl. note, I said China and not a specific city. And they did not care what others thought.
In Spain and warmer parts of Italy , an afternoon siesta is very normal. Pl note - I said Spain and not a specific city.

I do not know why this is a big deal.
I have had my horrible weeks and have slept at my desk in the afternoon for 10 minutes.

Being opinionated is one thing. Self flagellation AND opinionated AND judgmental -

Ah, but Neelaji, these are all gleat countries onlee, only HAL (because it admits it's mistake) is incompetent and ofcourse jour truly and all oher unwashed SDREs are some of the most stupid beings who betray and let down their country every now and then..the funny part is we are having a debate over NOTHING... a speculative drawing that might've been just a representation of a 5th gen plane not related to mk.3 or AMCA and here we are... and I get warning for relatively not saying anything

member_22906 · Post by **member_22906** » 14 Jul 2012 01:00

Kartik wrote:I've heard of things that are unheard of in the US or India- having beer or wine during lunch breaks. This happens quite frequently in Germany where a few of my colleagues have worked. They say that its not at all frowned upon for a guy to have a couple of beers at lunch and then come back to work. In the US, most engineering companies would fire someone for such a thing.

Perceptions of what is right or wrong differ in each country.

You don't have to go to Germany for such a practice. I worked earlier in a German organization in BLR and there also having beer for lunch and returning to work was a very acceptable practice. In fact fair # of official dinners used to have beer served in office premises (till there was some sarkaari issue regarding liquor license etc req.

)

Nevertheless, we discussed enough about sleeping and drinking... About time we return to the LCA thread

SaiK · Post by **SaiK** » 14 Jul 2012 07:22

Thanks A Sharma for that post..

He mentioned that CLAW was never an issue in the planning of flight testing. He stated that to the best of his knowledge TEJAS was the only fly-by-wire fighter aircraft in the world that had test flown over 1900 sorties without even a single major problem. He also appreciated that the team had contributed in many other areas apart from CLAW such as Notch filter design, PID and so on. He concluded his speech by asking the team to continue in the same manner in future.

>>har har mahadev bhu point.

Vivek K · Post by **Vivek K** » 14 Jul 2012 09:11

Sridhar.E wrote: can we stop this now? Stop derailing the thread

Sridhar your request is somewhat strange. I have made two posts - one saying "+1" to Katare's post and another questioning the parameters 9I.e. lunch break or otherwise) of lengthy post by several posters regarding how productive it is to sleep on the job. So then is your post directed at me or at others?

suryag · Post by **suryag** » 16 Jul 2012 20:51

Flight test update

LCA-Tejas has completed 1941 Test Flights successfully. (12-July-2012).
(TD1-233,TD2-305,PV1-242,PV2-222,PV3-348,LSP1-74,LSP2-237,PV5-36,LSP3-75,LSP4-56,LSP5-105,LSP7-4,NP1-4)

from

LCA-Tejas has completed 1937 Test Flights successfully. (12-July-2012).
(TD1-233,TD2-305,PV1-242,PV2-222,PV3-348,LSP1-74,LSP2-237,PV5-36,LSP3-73,LSP4-56,LSP5-103,LSP7-4,NP1-4)

Vashishtha · Post by **Vashishtha** » 16 Jul 2012 21:33

Any special celebrations planned for 2000 flights mark?

suryag · Post by **suryag** » 16 Jul 2012 22:26

^^^ may be but what would be cause for celebration here would be the realisation of this line from ADA's NFTC subpage

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

Future Plan
To undertake flight testing of all prototypes of LCA and complete the flight testing leading to technology demonstration of LCA in 220 flights and initial operational clearance in 2000 flights

Ardeshir · Post by **Ardeshir** » 18 Jul 2012 12:03

http://timesofindia.indiatimes.com/indi ... 023942.cms

NEW DELHI: At a time when the US is fast-developing hypersonic bombers capable of flying at 20 times the speed of sound, India's largely home-grown Tejas light combat aircraft will "not be ready to go to war" anytime before 2015.

This is the kind of irresponsible DDM reporting that really irks me.

rajanb · Post by **rajanb** » 18 Jul 2012 12:05

^^^ I know. I suppose they are referring to it being 'fully mature". Not realising that it will continue to be tweaked and improved over its entire life cycle till they decide to phase it out in decades.

member_19648 · Post by **member_19648** » 18 Jul 2012 12:13

The LCA Tejas has, as yet, not got simple clearances, such as an all-weather-capability and lightning strike clearance. The strategic role of this aircraft is in question, although it has world-class avionic capabilities. It is unlikely to be inducted in effective numbers till 2018 or even later.

This one is even more irking!!! I knew Tejas was already cleared for all-weather operation? What is this DDM talking about? Also, yet to get clearance doesn't mean it will not get clearance!!!

Singha · Post by **Singha** » 18 Jul 2012 13:11

now that we have many airframes flying, perhaps its time to push the envelope and use the monsoons to attain heavy rain and lightning strike clearances?
CABS has a lightning strike chamber inhouse. these two are good things to get done.

rajanb · Post by **rajanb** » 18 Jul 2012 13:13

Singha wrote:now that we have many airframes flying, perhaps its time to push the envelope and use the monsoons to attain heavy rain and lightning strike clearances?
CABS has a lightning strike chamber inhouse. these two are good things to get done.

Singha, I remember that it was tested in the CABS lightning facility?

Singha · Post by **Singha** » 18 Jul 2012 13:17

http://lca-tejas.org/testing.html

pics above show the individual components have been lightning tested but not a whole plane with "live" electrical systems in ON state perhaps.
while I am no expert on this, this might mean
- they need to power up a plane using the APU, electronics all ON and strike it with shocks, install dummy pilot with sensors to measure any shock to human
- power up a plane on its own engine and see if the engine electronics is safe under shock
- fly a plane up into the storm clouds and sit around for lightning to stike for the final "clearance" test

member_23657 · Post by **member_23657** » 18 Jul 2012 13:24

Prasant wrote:http://timesofindia.indiatimes.com/indi ... 023942.cms

NEW DELHI: At a time when the US is fast-developing hypersonic bombers capable of flying at 20 times the speed of sound, India's largely home-grown Tejas light combat aircraft will "not be ready to go to war" anytime before 2015.

Journos like Raj, if born in Chin or Paki land would have been lynched to death by mercenaries for being so irresponsible.
I am sure he has no knowledge of armed forces of the world and their cutting edge technologies
Luckily, people like him(ajai, shiv etc) are born in India where there is lot of tolerance shown...

rajanb · Post by **rajanb** » 18 Jul 2012 15:26

Singha wrote:http://lca-tejas.org/testing.html

pics above show the individual components have been lightning tested but not a whole plane with "live" electrical systems in ON state perhaps.
while I am no expert on this, this might mean
- they need to power up a plane using the APU, electronics all ON and strike it with shocks, install dummy pilot with sensors to measure any shock to human
- power up a plane on its own engine and see if the engine electronics is safe under shock
- fly a plane up into the storm clouds and sit around for lightning to stike for the final "clearance" test

Surprising that the whole plane hasn't been tested, and they are doing a lot of flights, at least till last week. Having spent a lot of time with both Nashik and BLR HAL being my customers and some of the test pilots as friends, I was under the impression that a lightning test would be something that they would carry out in the initial stages itself. Not after >1900 tests.

Unless they are waiting for this

- fly a plane up into the storm clouds and sit around for lightning to stike for the final "clearance" test

Crikey and I have flown over the twin cities of Hyd and Sec'bad, clinging onto the aluminium door frame of a Pushpak, with canvas cover of the door flapping, during monsoons and low clouds, hoping I didn't fall out.

Ardeshir · Post by **Ardeshir** » 18 Jul 2012 15:29

^^That is a pooch I have as well. Given that while flying, they might come across inclement weather, including lightning, wouldn't this have been amongst the first few tests to have been conducted? Especially since we are close to 2000 test flights.

member_19648 · Post by **member_19648** » 18 Jul 2012 15:53

Prasant wrote:^^That is a pooch I have as well. Given that while flying, they might come across inclement weather, including lightning, wouldn't this have been amongst the first few tests to have been conducted? Especially since we are close to 2000 test flights.

Don't think just flying through inclement weather and getting struck by a rogue lightning would lead to its certification as lightning proof, they would have to collect test data on effect of lightning on important sub systems under harsh controlled environments. But I do agree, they might have been among the first tests conducted, even there was a news of a rogue fire incident while conducting such tests, don't remember the exact details.

Ardeshir · Post by **Ardeshir** » 18 Jul 2012 16:09

^Of course they would have to collect test data in a controlled environment, which is what my question points to - theoretically, prior to any such such system taking off, shouldn't it be tested for lightning strikes?

By the way, I am trying to read up about this, and have come across some links:
1. http://www.compositesworld.com/articles ... structures
2. http://blog.testequipmentconnection.com ... d-testing/
3. www.ece.unm.edu/summa/notes/In/IN615.pdf
4. http://www.chomerics.com/tech/testrepor ... 0Evals.pdf

pragnya · Post by **pragnya** » 18 Jul 2012 17:23

Ivanev wrote:even there was a news of a rogue fire incident while conducting such tests, don't remember the exact details.

Ivanev, the test you are referring to was the customary ignition test done on the test rig itself before the lightning test is done on the components (in this case the fuel tanks). IOW, it was the 'testing of the test facility' during which the 'unusual' (as CABS official put it) accident happened injuring 10 people.

read the last 2 paras of the link below. it was a minor incident not affecting the LCA certification.

http://tarmak007.blogspot.in/2010/12/lo ... -cabs.html

Neela · Post by **Neela** » 18 Jul 2012 20:16

Lightning protection - Have some basic knowledge in ESD ( electrostatic discharge ) and will hazard a guess.

Lightning strikes when two areas of oppositely charged particles/regions exist and a electrical short happens. When an aircraft flies through such a region, it could inadvertently be part of the shorted path . However, the aircraft will have to provide a path for current to flow out without allowing the current to reach any of the internal circuitry. The current source and current sink will always have to be outside of the aircraft and should never have a path to any part under the skin. This I think is the fundamental premise I guess.
In ICs/chips only after we know where the pins connecting to the external world are , can we plan for ESD discharge circuitry - and this does not happen before the chip design is finalized/or is near finalization .
Applying the same logic, only when we know where various electronics/electrical components are can we:
- provide isolation for interference protection
- provide non-conducting paths immediately below the conducting skin of aircraft.
- avoid needless protection where it is not needed.

Am no expert on either ESD or lightning - just a guess.

The LCA skin has both carbon fibre and metal - so I do not know how that works.

EDIT:
Changed wording for clarity.

manum · Post by **manum** » 18 Jul 2012 20:58

The main thing about lightening is that it shall not surpass the skin...if charge passes inside something or the other can fail or go out of the hand..

so lightening test is all about the skin that the charge gets distributed on the skin and then gets disposed off in atmosphere...

how easy or tough it is in a supersonic flying thing is I am not aware of though...

rajanb · Post by **rajanb** » 18 Jul 2012 21:29

^^^^ For those of you who are interested.

http://www.compositesworld.com/articles ... structures

manum · Post by **manum** » 18 Jul 2012 21:53

I hope its as simple as painting the aircraft in copper/aluminium paint.

or mixing the metal dust in the paint and painting it in multiple layers...

but anyways if not...then each aircraft will have to devise its own way to deal with lightening unique to its design and design consideration...if lightening was given a proper thought in choice of composites itself...

anyways I think we are in process of creating our own data model specific to LCA design and finding out our own solution which may be cocktail of various simple scientific jugaad...