LCA News and Discussions, 22-Oct-2013

Victor · Post by **Victor** » 28 Jan 2015 07:02

Thakur_B wrote:Ah, the resident aerodynamics expert WBUH (wikipedia be upon him,) who can't convert miles into kilometers, is back punching keys at the keyboard. And I thought something major must have happened to see this kind of activity in the thread.

And I suppose you are the expert who everyone should bow to? At least take the opportunity to refute with something resembling sane arguments something you don't agree with instead of gratuitous bullsh!t.

NRao · Post by **NRao** » 28 Jan 2015 07:10

Quite true, anything as complex as the LCA where the wheel had to be re-invented multiple times, cannot succeed without the cooperation and dynamism of all agencies and personnel involved.

We see this happening wrt IN fleet procurement. It seems to me the Labs and manufacturers are quite happy to cooperate with the services if given a chance, but it looks like they have not been given this chance with the IAF and IA apparently.

Cooperation should include some amount of risks too - failures and early adoption of platforms, as an example even if IOC has not been reached.

Thakur_B · Post by **Thakur_B** » 28 Jan 2015 07:17

Victor wrote:
Thakur_B wrote:Ah, the resident aerodynamics expert WBUH (wikipedia be upon him,) who can't convert miles into kilometers, is back punching keys at the keyboard. And I thought something major must have happened to see this kind of activity in the thread.
And I suppose you are the expert who everyone should bow to? At least take the opportunity to refute with something resembling sane arguments something you don't agree with instead of gratuitous bullsh!t.

Done plenty of times with you Victor (WBUH), how about you take your own advice. The board is still waiting for your rebuttals to the replies to your Tejas infographic posts

. Everyone can see through your flamebaiting, even a person like me who does not appreciate HAL or agree with the goals of LCA program.

Victor · Post by **Victor** » 28 Jan 2015 07:25

Shalav wrote:
Victor wrote:
IAF contends the HAL chief should be someone who "understands aerospace concepts" and can "transform" HAL into a cutting-edge company, capable of delivering on time

What HAL got was an ex-Railways guy to run it.

This is completely nonsensical - if anything a "railways guy" with public sector manufacturing experience is better as getting work output from the shopfloor, than a hypothetical AVM who has had his orders obeyed all his professional life, and not the first clue as to how to run a heavily unionised civilian factory.
.

I don't suppose you have worked in a production environment. Very rarely, if ever, does the boss deal with floor workers. Unionized or otherwise makes absolutely no difference. And yes, his orders will have to be obeyed or danda will fall hard. We know how railways and other psus have worked out so please let's not go there.

Victor · Post by **Victor** » 28 Jan 2015 07:32

Thakur_B wrote:[ still waiting for your rebuttals to the replies to your Tejas infographic posts .

I rebutted every argument made but if you found something not answered to your satisfaction, I'll try to find the time to look into it. Again, please cut out the gratuitous bullsh!t. You don't need to crawl around at that level to make a point.

Everyone can see through your flamebaiting, even a person like me who does not appreciate HAL or agree with the goals of LCA program.

Just learn to ignore the itch. Least pain that way.

Victor · Post by **Victor** » 28 Jan 2015 08:02

Shalav wrote: 1. The IAF's business is defending the territory of India, not running factories.

I agree with this. But given the utter failure of HAL/DRDO/ADA in its eyes, it is desperately looking for competitors to fill the space. Thankfully Modi feels that way too so we will see some big changes soon no doubt.

The same DRDO and HAL is doing quite well with the IN thank you very much. Just goes to show its not just about HAL or DRDO, the IAF should stick to their specialty, and let others do theirs.

Well first of all who says DRDO and HAL are working out OK with navy LCA? The PPT presentation above by capt Maolankar points out quite clearly the design problems being faced with undercarriage and intakes as well as the intention to only induct Mark 2 in active duty after the deficiencies in Mk1 are corrected.

Everyone agrees that LCA is not a POS and we need to capitalize on it. However the general consensus from both the IAF and navy is to stop flogging it and move ahead with Mk2 without wasting time. The longer we delay Mk2, the later will LCA join IAF and navy in anything other than a cosmetic way. For some reason, DRDO/HAL are insisting that they accept Mk1 and don't care to have it serve in cosmetic fashion as long as they can chalk it up as "operational" and "mission accomplished". So far, MoD has sided with this but all signs point to a change.

srai · Post by **srai** » 28 Jan 2015 08:29

If the IAF/IA guys at the top making decisions are anything like Victor then good luck to the LCA and Arjun programs! The odds are stacked against them.

rohitvats · Post by **rohitvats** » 28 Jan 2015 08:38

Shaun wrote:Ban big ticket imports , things will change rapidly. The argument that our armed forces should be equipped with the best weapons available just doesn't hold ground when there is indigenous alternatives available. I just can't fathom the idea why Army and Air Force are so reluctant when it comes in inducting indigenous weapons. N number of trials, changing requirements ..etc.

Look at the Armour and equipment level of our infantry who actually are fighting the "real" war and sacrificing their lives. here , no compromises should be made for security , safety and comfort of them even if it requires large amount of imports.

I've asked this of others and may be you can also pitch in - Can you name 10 products from DRDO stable which are available but yet, IA and IAF are importing them from abroad.

Suraj · Post by **Suraj** » 28 Jan 2015 09:02

rohitvats wrote:I've asked this of others and may be you can also pitch in - Can you name 10 products from DRDO stable which are available but yet, IA and IAF are importing them from abroad.

Excuse me for butting into this in civvie wear, but this very question underlines the problem. The IA/IAF are not a master surgeon in the middle of a complex operation who just barks out 'scalpel' or 'retractor', for the nurses, analogous to the Indian state organizations, ranging from MoD, DRDO and FinMin, to feed it the tools.

I've heard references to military assertions of the 'our job is to fight, not design toys. Just get us the best stuff to fight with and leave it to us'. That's very myopic. Our military forces assert our independence. Our independence comes from continuously accruing freedoms to build our socio-economic lives, among which is independence in developing the very weapons that keep us independent.

When the armed forces demands the best from outside because it's better on paper, or any number of other reasons while being unwilling to painstakingly collaborate and develop locally, they also make us dependent on the whims and fancies of those nations. In other words, they're undermining the very freedoms they are tasked to defend and further.

Getting back to the original statement, it suggests the DRDO independently develops something to readiness as defined by the military entity, and the military clinically accepts it. That's really not how lifecycle development occurs. Each arm of the military needs independent design specification organizations who can work with domestic design and manufacturing entities to iteratively develop their products.

The original statement can also be stated in corollary as 'has IA/IAF scrupulously avoided any procurement from abroad that was not an entirely finished product that required no iterative enhancement at all ?' The answer is no. When they bought their current frontline fighter, it did not exist. They got Su-30Ks, which were upgraded to MK-1s, which were upgraded or wholesale replaced with MKIs, approximately 8-10 years after the original aircraft started flying in their colors. Ditto for the T90s. I'm sure there are several more that others more familiar with the mil forum can point out. Since the corollary is not a valid statement, the original question cannot be asserted meaningfully.

This isn't to suggest that the problem lies with the armed forces. The lack of a substantial domestic industrial design and manufacturing base hampers a lot of armaments development, from the low end to cutting edge. However, an effective solution involves fixing both, not papering over one by undermining the freedoms the other is tasked to defend.

Indranil · Post by **Indranil** » 28 Jan 2015 09:39

Victor sahab,

I will be brutally honest. As a moderator, I have a job to keep this thread clean, but you are a becoming a big impediment.

Believe it or not, I wanted to keep posters who could discussed flaws in LCA. But, clearly, you have no idea of the actual problems. I don't think you can differentiate developmental challenges/milestones and genuine problems. Therefore, page after page, you have chosen the indefensible points and make utterly nonsensical posts based on very limited and often incorrect knowledge of aerodynamics, avionics and history of aircraft development.

This has gone on for far too long. I will not allow this anymore.

Personally, I like to listen more to the people who hold opposing views to mine.

Quite frankly, from what you have written in the recent past past 10 odd pages is almost always complete nonsense which flies in the face of physics. It is very evident to anybody who has studied any bit of aerodynamics. There are legitimate problems with the LCA Tejas, which you clearly do not know. Instead you chose to defend the indefensible points

Indranil · Post by **Indranil** » 28 Jan 2015 09:59

MODERATOR NOTE:

I have decided that the quality of discussion on this thread needs to be returned to the glory days. The cr@p which is passed for posts these days will be allowed to be burned by the gurus and moderators.

Post here only if:
1. You have news on LCA or LCA-program.
2. You have a question and Googling out the answer is not easy. Posters with stupid questions will be warned. Mark your questions with numbers and keep them to the point.
3. You can answer questions with proper technical points. Learn the difference between knowing and thinking that you know. Don't let gurus and moderators point it out to you. It will not be pretty.
4. You found out something about a shortcoming/problem/quality of LCA Tejas, which you think is not known to most.

If you have suggestions/problems with this kind of moderation, report this post along with your thoughts.

SaiK · Post by **SaiK** » 28 Jan 2015 10:32

http://www.iitten.com/lca-tejas-compound-delta-wings/
Tejas MK-II and the Naval variant will have further improved aerodynamic structure They’ll have LEVCONS, they work similar to the Close coupled Canards, they reduce the drag, the LEVCONS deflect downwards, they permit higher angle of attack without airflow separation over the parts of fuselage above the air intakes, + helps in improving spins too, they also help in improving the lift capability.

anyone interested can comment (t)here

Indranil · Post by **Indranil** » 28 Jan 2015 11:01

RV,

Let us not use this thread to providing certificates to the IAF/IA. Also, let us only discuss LCA Tejas. Let me paraphrase 2 questions for you. I am pretty sure you will learn a lot while finding the answers to these simple questions.

1. Name any modern fighter which is developed with the support of its native airforce?
2. Name any fighter program which is anywhere close to completely developed when it is accepted by its airforce? When is a fighter aircraft generally first accepted by its airforce?

You had a very genuine question before:
1. Where are the serially produced aircrafts that IAF could have inducted?
Ans: This one stems from one of greatest mismanagements of the LCA program and the lack of customer involvement. These are clearly captured by the paper by Cmde Muthanna. Traditionally, the customer and the developer sit down together and chalk out the minimum set for the first Mark/Block (For example listen to Mao's talk on NLCA Mk1 and Mk2). This generally is the point where the developer is sufficiently confident of the flying machine being able to be pushed to the corners of the envelop and integrated with a minimum set of armaments identified by the user (this is the answer to q2. above). The latter is seldom achieved before a couple of years into fielding the aircraft. Anyways, this crucial step was never undertaken by the IAF. Instead IAF changed its specifications for the first aircraft! ADA/HAL finally decided that IOC-II will be that first freeze point. This only happened in late 2013. There are many reasons cited for this delay, some legitimate and some excuses for lathergy. There was another crucial mistake by HAL/MoD/IAF. You see HAL cares about its balance sheets. Tejas is probably its least profitable and highest risk project currently (next only to HTT-40). So it did not invest in setting up the production line so that it is ready to roll out fighters from the beginning of 2014. IAF also showed no interest except washing the linen in the open (at every instance it could) and MoD was the most inept in decades. End result is that we will only have a stabilized assembly line by 2015. What continues to be inexplicable is that IAF is still not providing orders so that the pipeline capable of producing 16 aircrafts per year can be made ready by 2016. All this while it cries about squadron strength and its pilots keep bailing out of old Migs! The situation is worse than our tank procurement. At least T-90 is a formidable and newly produced tank. Our Migs are vintage and have no life left in them. They are falling out of the skies. One crashed yesterday! The replacements are knocking on our doors, at less than 30 million a piece! Really, I have talked to a lot of people, in the know. A lot of people understand/sympathize with IAF pre-IOC. Nobody understands their current actions! The silver lining is that Parrikar can kick butts and Rafales will not come easy. Let's see.

Victor · Post by **Victor** » 28 Jan 2015 11:46

Amen to the last sentence. His actions will tell us all we need to know. Rest is guesswork.

member_28640 · Post by **member_28640** » 28 Jan 2015 11:47

When asked typical DDM questions about the Tejas, India Head of KPMG had this to say (They device "complete solution – from strategy formulation to execution" for us)

After 32 years of development, the LCA was finally handed over to the Air Force. Is the delay justified? How does Tejas fare?

New aircraft design, development and certification do take decades. Specifications also change as technology advancements happen constantly. It is premature to comment on how Tejas may fare. A better approach could have been to use off-the-shelf components and then replace them, over time, with made-in India ones. The systematic sidelining of the Indian private sector – where India’s best engineers go every year – has been a big mistake. No aerospace power in the world is 100 per cent self-sufficient. The US military uses products from UK, French, German, Swedish and Israeli companies. The Eurofighter Typhoon is produced by four European countries that, incidentally, fought two World Wars among them. Focus and global collaboration is key.

Please find quoted the article and the voice of KPMG towing the murican line
http://www.thehindubusinessline.com/ind ... 827224.ece
While I get down to research what an "Audit, tax and advisory" company is doing in the loop in Indian defence.. Gurus please help me out

Indranil · Post by **Indranil** » 28 Jan 2015 12:05

SaiK wrote:
http://www.iitten.com/lca-tejas-compound-delta-wings/
Tejas MK-II and the Naval variant will have further improved aerodynamic structure They’ll have LEVCONS, they work similar to the Close coupled Canards, they reduce the drag, the LEVCONS deflect downwards, they permit higher angle of attack without airflow separation over the parts of fuselage above the air intakes, + helps in improving spins too, they also help in improving the lift capability.
anyone interested can comment (t)here

That guy has half-baked knowledge.

Tejas fighter has “Compound Delta” rather than Pure Delta wings, which has every advantage of delta but no disadvantage.
Delta wing have some disadvantages like, they have lower AoA ( AoA is orientation with line of flight. All wings can have 0 to 360 AoA. The question is critical angle, this dependent on many things like sweep and aerofoil), they are unable to trim out the nose-down pitching moment from flaps,the require higher thrust, high wing loading is required ( This is completely opposite of what happens. First of all, wing loading is always "obtained", never "required". Second, there is no relation between wing loading and shape of the wing. Third, typically, designers can accommodate larger wings if they go for delta wings giving them the low wing loadings) and higher wing loading effects maneuverability, Supersonic maneuverability restricted ( Completely the opposite of what happens), higher drag ( When? In slow speed turns, yes. In transonic and supersonic cruise, no.)and many others things.
There the HAL team opted for another option the the “Compound Delta”, this are bit swept at the front portion, they indirectly work similar to the Canards helps in the lift and improving maneuverability, this are also very effective in supersonic low level flights, external load doesn’t much effect the quality of flying + lower drag.
Tejas MK-II and the Naval variant will have further improved aerodynamic structure They’ll have LEVCONS, they work similar to the Close coupled Canards, they reduce the drag, the LEVCONS deflect downwards, they permit higher angle of attack without airflow separation over the parts of fuselage above the air intakes (It is rather controlability at low speeds rather than capability. The designers speculate that they will have enough control so that the FCS can set the engine thrust and AoA in such a way that the approach speed is independent of the weapon load), + helps in improving spins too (how?) , they also help in improving the lift capability.

sattili · Post by **sattili** » 28 Jan 2015 12:55

GopiN wrote:When asked typical DDM questions about the Tejas, India Head of KPMG had this to say (They device "complete solution – from strategy formulation to execution" for us)
Please find quoted the article and the voice of KPMG towing the murican line
http://www.thehindubusinessline.com/ind ... 827224.ece
While I get down to research what an "Audit, tax and advisory" company is doing in the loop in Indian defence.. Gurus please help me out

KPMG is a consulting company which tracks various industries including defense and aerospace. They have been publishing various reports on Indian defense & aerospace sector for several years. Some of the studies were done with CII partnership. Btw, they also published reports on other sectors as well.

Especially after DPP was put out by the previous government, many consulting firms (KPMG, PwC etc) created lot of buzz about the Indian defense sector being opened for pvt players and also to enthuse international biggies to invest in this sector. There will be bias in those reports towards favoring pvt industry. However several of those contain valuable information about how our defense industry is structured and way forward etc. Some of the papers worth reading (this is not an exhaustive list, just a sample):

1. KPMG Paper

2. KPMG

3. This one from PwC

4. PwC

5. this one from IDSA

rohitvats · Post by **rohitvats** » 28 Jan 2015 14:14

indranilroy wrote:RV,

Let us not use this thread to providing certificates to the IAF/IA. Also, let us only discuss LCA Tejas. Let me paraphrase 2 questions for you. I am pretty sure you will learn a lot while finding the answers to these simple questions.<SNIP>

Indranil - My post was more about the narrative on the forum about IA/IAF being 'anti' indigenous products than about LCA per se. LCA is a subset of the discussion. As is the Arjun program. Long story short - if IA/IAF are 'anti-Indian' products, then a question needs to be asked as to who consumes everything else the DRDO has developed or is developing? And I'm not talking about missiles here. If the same IAF is happy using spin-off from technology developed for LCA in other programs, why does it have issues with the LCA?

Also, the little bit that I've managed to read on the subject, tells me that Indian Navy does better with DRDO because of two reasons - (a) It does not go by what DRDO says can be done and in what timeline. If this point is a commentary on project management and technical knowledge of IN, than it also says a lot about DRDO (b) As a percentage of involvement, DRDO has least engagement with Indian Navy.

You've already read the riot-act here. So, this is last post here on the subject. Will make a detailed post later on the subject.

Shreeman · Post by **Shreeman** » 28 Jan 2015 14:27

Has SP2 flown? Has NP2 flown? Any news on tailhook ops in goa or BLR? What is HAL/ADA showing at AI15? Its three weeks out, there should be something public re small aircraft display.

member_28640 · Post by **member_28640** » 28 Jan 2015 15:34

sattili wrote:
GopiN wrote:When asked typical DDM questions about the Tejas, India Head of KPMG had this to say (They device "complete solution – from strategy formulation to execution" for us)
Please find quoted the article and the voice of KPMG towing the murican line
http://www.thehindubusinessline.com/ind ... 827224.ece
While I get down to research what an "Audit, tax and advisory" company is doing in the loop in Indian defence.. Gurus please help me out
KPMG is a consulting company which tracks various industries including defense and aerospace. They have been publishing various reports on Indian defense & aerospace sector for several years. Some of the studies were done with CII partnership. Btw, they also published reports on other sectors as well.

Especially after DPP was put out by the previous government, many consulting firms (KPMG, PwC etc) created lot of buzz about the Indian defense sector being opened for pvt players and also to enthuse international biggies to invest in this sector. There will be bias in those reports towards favoring pvt industry. However several of those contain valuable information about how our defense industry is structured and way forward etc. Some of the papers worth reading (this is not an exhaustive list, just a sample):

1. KPMG Paper

2. KPMG

3. This one from PwC

4. PwC

5. this one from IDSA

Thanks saar, clears a lot ...

Altair · Post by **Altair** » 28 Jan 2015 16:53

Sattili
Please use short URLs. Your post screwed up the page scrolling totally.
Thanks

Karan M · Post by **Karan M** » 28 Jan 2015 16:59

Those presentations are mostly generic gyaan repackaged for an audience which is more eager to see operational outcomes and improvement. Most of the stuff in those prezzos is also pulled together by MBAs in their 20's who know as much about A&D or HAL or LCA or IAF as any other guy their age.
The usual method is to scan half a dozen newspapers/mkt news feeds and then reprint whatever those guys say. So if your media and journals keep saying LCA is bad, etc these reports will mostly regurgitate the same line. Nobody will (unless they are commissioned to do so) go around to ASTE or DRDO or the labs and ask detailed questions.

In the past, wiki (which is pretty hopelessly out of date, eg production Agnis are shown as devpt etc on some pages) was used as source (easy to make out by syntax and statements made) for some of the reports.

The stuff then goes to a partner or senior consultant who just packages it into his desired message (depending on audience) and adds his name. That guy will be some rtd forces guy or ex MOD babu parachuted to the top to be the practise head and reporting to some Tax/Audit guys who are the real oldies who run the entire division. In short, don't use those reports as some expert speak on any industry.

deejay · Post by **deejay** » 28 Jan 2015 18:18

While we wait for news on SP 2, here is something from HAL on Tejas:

http://www.oneindia.com/india/tejas-has ... 34122.html

Quoting parts relevant to HAL

OneIndia Exclusive: Tejas has put India on a vibrant technology flightpath, says HAL Chairman Tyagi Written by: Dr Anantha Krishnan M Updated: Wednesday,

......

More Tejas to justify Make in India dream

Terming Tejas as one of the finest flying machines of his times, Tyagi hoped that Prime Minister Narendra Modi's Make in India dream will find more answers by HAL getting additional orders for Tejas.

"Tejas has inspired Indian aerospace and defence community. It has given confidence to our industry to partner with a national programme. Tejas has put India on a vibrant technology flightpath that will fetch glory for all other future projects as well. I am impressed by PM Modiji's push for the making military ware in India," Tyagi added.

.....

deejay · Post by **deejay** » 28 Jan 2015 18:29

SJha has this to tweet:

Saurav Jha @SJha1618 · now 38 minutes ago
The DRDO-HAL Tejas Mk-I crossed a new milestone this winter with three consecutive startups in Leh after being soaked overnight at -15 deg.

Image from SJha's tweet

SaiK · Post by **SaiK** » 28 Jan 2015 19:53

that is one mean tejas with the himalayas. what are those dual camera like appearance (at least 15 to 20* angle between them) on the vert stab?

Indranil · Post by **Indranil** » 28 Jan 2015 20:03

deejay wrote:SJha has this to tweet:

Saurav Jha @SJha1618 · now 38 minutes ago
The DRDO-HAL Tejas Mk-I crossed a new milestone this winter with three consecutive startups in Leh after being soaked overnight at -15 deg.
Image from SJha's tweet

Full Press Release:

With three consecutive start-ups of its engine after overnight soak in extreme cold (around -15ºC) conditions of Laddakh winter, that too without any external assistance, Tejas, the Indian Light Combat Aircraft has achieved yet another and a rare distinction. Starting the fighter aircraft under such extreme condition without any external assistance or heating is a technology challenge. The requirements become further stringent when the starting is to be done three times consecutively with a partially charged battery. Team LCA led by AERD&C of HAL, and members from ADA, NFTC, IAF, CEMILAC and DGAQA have succeeded in achieving this. “The team LCA has achieved a technological breakthrough”, stated Dr. PS Subramanyam PGD (CA) & Director, ADA.

The engine starter is developed indigenously by HAL Aero Engine Research and Design Centre (AERDC), Bangalore. Prior to aircraft tests, the Jet Fuel Starter (JFS) was extensively tested on test rig to meet starting conditions across the operating altitudes including Leh (10,700 ft.) and Khardungla (18300 ft.). The control software of JFS was fine tuned to work at all operating altitudes with no adjustments from cockpit. GE-F404-IN20 engine start up control schedule was also varied with several control patches to establish reliable start.

They are speaking of the GTSU-110.

Beautiful picture from the tests below. Click for higher resolution.

Remarks:
1. The parachute door has been changed in SP-1 and PV-6 to a clam-shell design which does not come off the body. This is also a very useful modification. Nobody needs to go search for it after the plane lands. Also, it doesn't get banged up.

Questions:
1. The current air intake for the APU is grotesque. Certainly, it will go through a review. Does anybody know why they are not using a NACA airduct?
2. Does anybody know why the skirting joining the fuselage to the engine nozzle does not go all the way around? What is the gap used for?

sattili · Post by **sattili** » 28 Jan 2015 20:43

Deleted

Avinandan · Post by **Avinandan** » 28 Jan 2015 21:07

indranilroy wrote: 2. Does anybody know why the skirting joining the fuselage to the engine nozzle does not go all the way around? What is the gap used for?

Hi Indranil,
I don't know the answer, but could you please elaborate what do you mean by "does not go all the way around?".
Did you mean the black half ring that doesn't extend to the upper semi circle of the engine nozzle ?

Also wanted to ask couple of questions from my side:-
1. What is that triangular hole and rectangular part painted near the air-brakes.
2. It looks like the 8 holes in the air-brakes have now become smaller. Please confirm.

SaiK · Post by **SaiK** » 28 Jan 2015 21:24

for discussions, pay attention to 'key notes' in those articles.. example: pwc.

shiv · Post by **shiv** » 28 Jan 2015 21:42

indranilroy wrote: 2. Does anybody know why the skirting joining the fuselage to the engine nozzle does not go all the way around? What is the gap used for?

I thing that takes boundary layer air from that part of the fuselage and vents it via the rectangular opening above the wing seen in the other photo taken from above and behind.

Indranil · Post by **Indranil** » 28 Jan 2015 21:45

Avinandan wrote:
indranilroy wrote: 2. Does anybody know why the skirting joining the fuselage to the engine nozzle does not go all the way around? What is the gap used for?
Hi Indranil,
I don't know the answer, but could you please elaborate what do you mean by "does not go all the way around?".
Did you mean the black half ring that doesn't extend to the upper semi circle of the engine nozzle ?

Yes, the TDs and the first PVs used to have the skirting go all the way around the circle. But they also had dedicated afterburner venting airducts.

Later these venting airducts were removed along with the upper half of the skirting.

Notice that they cannot remove the skirting from the lower part because there is lot to protect there (Click for higher resolution)

Notice, that the other F404 users like the F-18 or Gripen don't need this gap. The skirting foes all the way around.

Avinandan wrote: Also wanted to ask couple of questions from my side:-
1. What is that triangular hole and rectangular part painted near the air-brakes.
2. It looks like the 8 holes in the air-brakes have now become smaller. Please confirm.

1. The triangular hole looks like a NACA air duct for ventilation of the avionics modules housed in the wing root extension fairing. But its direction is puzzling. The rectangular paint is only warning for jet blast from engine exhaust.
2. To my eye, they look the same.

Indranil · Post by **Indranil** » 28 Jan 2015 21:51

shiv wrote:
indranilroy wrote: 2. Does anybody know why the skirting joining the fuselage to the engine nozzle does not go all the way around? What is the gap used for?
I thing that takes boundary layer air from that part of the fuselage and vents it via the rectangular opening above the wing seen in the other photo taken from above and behind.

I think you misunderstood my question. Please see the clarification provided above. What you are speaking of is the boundary layer splitter plate and spill duct. That part is understood.

SaiK · Post by **SaiK** » 28 Jan 2015 22:15

it can't be anything to do with bypass.. if i may take a guess. how about a design approach to reduce IR signature?

what is this for?
http://images.dpchallenge.com/images_ch ... 580683.jpg

answer might be totally mechanical onlee

Raman · Post by **Raman** » 28 Jan 2015 22:57

The current air intake for the APU is grotesque. Certainly, it will go through a review. Does anybody know why they are not using a NACA airduct?

Actually, it is an ingenious solution. The APU intake is closed when the APU is not in operation (i.e., during most of regular flight operations) eliminating spillage drag.

What is that triangular hole and rectangular part painted near the air-brakes.

The triangular hole, as indranilroy pointed out, is a NACA inlet that is pointed the "wrong way", indicating that it is a vent of some sort.

The white rectangular part is a formation light. You can see it in operation here

SaiK · Post by **SaiK** » 28 Jan 2015 23:59

I think it is grotesque bulge because the projection is outward rather neatly tucked in (like NACA). I 'd not think an issue to skin them better in the production versions. I think it might add few wind tunnel testing though. BTW, the wrong way wala also can be NACA-ed, and there is nothing stopping them to consider aerodynamics on those areas.

It might be some engineers of my grade doing it!

Indranil · Post by **Indranil** » 29 Jan 2015 02:41

Saik sahab, no guess work as I had warned earlier. Let's keep the volume down and discussion as dense as possible.Please remove the marked posts.

Raman wrote:
The current air intake for the APU is grotesque. Certainly, it will go through a review. Does anybody know why they are not using a NACA airduct?
Actually, it is an ingenious solution. The APU intake is closed when the APU is not in operation (i.e., during most of regular flight operations) eliminating spillage drag.

Did not know that the intake closes. This makes it interesting. So what all does the Tejas APU power?

VinodTK · Post by **VinodTK** » 29 Jan 2015 03:04

India to hard sell Tejas at air show

India will showcase and hard sell its indigenous Light Combat Aircraft (LCA) Tejas at an air show here in February to prospective buyers from overseas, a top official said Wednesday.

"Tejas will be on flying and static display at the Aero India Show here from Feb 18-22 to solicit foreign buyers, as we have started producing them (fighters) for the Indian Air Force (IAF)," state-run Hindustan Aeronautics Ltd's (HAL) outgoing chairman R.K. Tyagi told reporters here.

The defence behemoth will also display military and civil variants of its Advanced Light Helicopter (ALH) Dhruv at the biennial international event in which producers, buyers, users and other stakeholders from the world over would participate.

The multi-role fighter is part of the first series production for induction into the IAF fleet.

"We have handed over the first aircraft (Mark-1 version) to IAF recently (Jan 17). Prospective buyers will be briefed on the fighter's unique features and abilities in combat role," Tyagi said on the occasion.

Defence Minister Manohar Parrikar also handed over the technical documents of the home grown LCA to Chief of Air Staff Air Chief Marshal Arup Raha here, though the fighter is yet to secure the final operation clearance (FOC) from the military regulator.

As a single engine multi-role supersonic fighter, Tejas will replace the IAF's ageing Russian-made MiG-21 fleet. The former will be inducted in six squadrons after the defence regulator, the Centre for Military Airworthiness & Certification (Cemilac) releases the FOC later this year.

The fourth generation fighter received the initial operational clearance (IOC-2) in December 2013 for evaluation by IAF ace pilots on various parameters.

Weighing 8.5 tonnes, Tejas can carry three tonnes of weapons, including air-to-air missiles, laser guided bombs, guns, conventional/retarded bombs and beyond visual range missiles.

Tejas is also fitted with digital fly-by-wire system, flight control systems and open architecture computer.

Each squadron will have 20 fighters and will be based at Sulur Air Force base near Coimbatore in southern Tamil Nadu.

In the design and development stage, HAL produced 15 LCA aircraft, including seven in the limited series production, two technology demonstrators, three prototypes, two trainer prototypes and one naval prototype.

Designed and developed by the state-run Defence Research and Development Organisation (DRDO) and its aeronautical agencies over the last three decades, the LCA project overran estimated budgetary costs and deadlines.

--Indo-Asian News Service fb/ml/bg

NRao · Post by **NRao** » 29 Jan 2015 03:18

Is that supposed to mean that the US in on board with selling the LCA with the GE engine?

Avinandan · Post by **Avinandan** » 29 Jan 2015 03:50

Thanks for the info and the pains taken to explain Indranil !

By the way, did you get the answer regarding LCA's wing blending similar to Rafale, Gripen ?

Indranil · Post by **Indranil** » 29 Jan 2015 05:38

Avinandan wrote:Thanks for the info and the pains taken to explain Indranil !

By the way, did you get the answer regarding LCA's wing blending similar to Rafale, Gripen ?

On the bottom? I think it will require too much work to blend it in without increasing the cross sectional area (which Tejas cannot afford to keep the wave drag down). Anyways, unlike the upper part, the bottom part does not affect the lift generation and control. However, a nicely blended bottom side does reduce interference drag. On the Tejas, there is a small amount of smoothening even on the bottom side to avoid acute or right angles.

One can complain that this surface could have been concave, especially at the edges so that the blending could have been perfectly smooth. But I guess it does the job.