Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Singha · Post by **Singha** » 19 Jan 2019 07:56

Told you so. Mighty f-solah has 17mm and faces the same birds in the tropics and desert like tsp, singapore, egypt, uae

Dileep · Post by **Dileep** » 19 Jan 2019 08:52

There are a lot of such 'pilot demands' that they do not dare to ask the goras.

Real story: There is a small device that gives a backup inertial reference to get you home if the primary system fails. Some test points of this device 'failed'. Why? When the plane rolls at high rate, this device shows an 'unacceptable' level of error (of a few degrees off the real angle).

The question is 1) would you be doing such high rate maneuvers when the primary inertial system is failed? 2) Would you be actually looking at this backup reference when you happen to do that maneuver? Both answers are 'no'.

The system was accepted after adjusting the performance expectations accordingly.

Indranil · Post by **Indranil** » 19 Jan 2019 09:47

Dileep Sir,

I agree with you on many aspects. First of all, who asks for such requirements in such an ad how manner? What are the SQRs for? This doesn’t reflect highly on professionalism.

Having said that, the 32 mm windscreen is present on the Su-30 (only other IAF bird to have it AFAIK). Also, the new requirement for LCA is is for change of the windscreen, so no question of change in height of canopy. AFAIK this will be done in house, not on foreign land.

rrao · Post by **rrao** » 19 Jan 2019 10:15

Dileep wrote:As per my sources, the new canopy thing is not so easy to do. It takes a lot of testing (at phoren land) to qualify. Also, there is a demand to increase the head clearance, so the aerodynamics changes too. His opinion is that this is another "I ask because I can. I am kashtamar!" demand by some IAF soljer, and he wants the chief to say "Shut up, take this and run". No other fighter we have satisfy this requirement.

Make such unreasonable demands, intentionally delay and cause a disarray in HAL production schedules and finally blame HAL, an organisation which is in the aerospace industry for the past 70 years. HAL is a major supplier to ISRO's successful programs apart from L&T etc..we are habituated to paying 400-600% more than the actual cost to goras happily and get knowingly cheated!!! When it comes to HAL, keep howling and whining!!! The visions of Seth Walchand sahab should not be forcefully blinded!!! HAL is a company run by the Govt diktats, unlike maggie noodles company and luxurious lazy and irresponsible DRDO!!Maharashtra govt gave 100 acres of land to a self made aircraft designer ,maker couple of years ago.. No knews about the company afterwards!!! Save HAL!!! Save indian Aerospace industry!!! Jai Hind!!!

Dileep · Post by **Dileep** » 19 Jan 2019 11:01

IR, Would there ever be an SQR that specifies the performance of the GRU in such detail (like max X degrees deviation during YYY degrees per second roll)? I guess not. Many of the demands are similar.

I am not sure if the increased canopy clearance is part of the current request. It was there at some point of time.

Another issue is, the HUD need to be tuned for the new canopy. There will be some very sour souls at Chandigarh for this.

Neshant · Post by **Neshant** » 19 Jan 2019 11:55

JayS wrote:The more I see Tejas program, the more my feeling gets cemented that this is all because of gross lack of pragmatism in Program management in all stake holders.

A lot of people in management have never risen to that rank by developing / inventing anything.

That is one of the biggest problems in management today.

Zynda · Post by **Zynda** » 19 Jan 2019 12:19

Design cases such as going for bird strike of higher weight depends on the actual number of such incidents in real life.

How many instances of such a big bird striking fighters in India have happened? If there are strikes, what is the probability rate of such strikes? What is the mean time between such big bird strikes? Months, years? If it is quite rare like 1 in 100, then would such a rate justify a complete redesign, testing & certification of the canopy & associated underlying structures, further pushing FOC times?

Rather, could IAF ask ADA to prove that in the event of a bird strike of such weight, the result is not catastrophic (to the plane as well as pilot) & indeed, the pilot can bring down Tejas safely at the nearest airbase. One has to remember, that there will be some increase in weight due to redesign...now for an event which is extremely rare, although the redesign will gurantee safety from such events, the rest of the time such a design is overkill which will impose some penalty (however small it is) on the performance of the aircraft.

Point is, IAF should start recording things such as above and present user with QRs which are more practical (& to add, I've heard stories from scientists where this is not the first time such a request, which the design house feels is not based on sound basis, has been made by forces).

To make it absolutely clear, I don't know the stats or accurate answer to any of the above. It is possible that IAF has indeed such data & their request could be based on such, in which case, I stand correct and tender an advance apology to Air Force folks

Ideally, the design house and end-user would discuss/negotiate on such QRs & come out with an acceptable compromise. Unfortunately in India, usually Govt labs don't hold such negotiating power (based on what I've heard).

gaurav.p · Post by **gaurav.p** » 19 Jan 2019 12:31

Flight test updates from ADA

Good to see the full force with which things are being worked out. It seems that they are busy with BVR integration

Other updates from lurking around
- on tejas fb page, it was stated that tejas won't see kaveri days. Let's hope something comes out of the offsets
- on tejas fb page, tejas as a LIFT concept is possible but needs coherence with all agencies
- on a twitter thread, it said that tejas might not see canards. I don't know if this chaiwala info is correct or not but I won't be sad if canards don't come. Mastering the close coupled canard and integrating it with FBW and the FCS is a huge task in itself IMO.
- some harsh criticism by an IAF veteran (I don't concur with it, but then I might be wrong) Link 1 Link 2
- regarding the updates on canopy is sad and shouldn't it be 400g rather than 40g? The testing videos on youtube seems a chicken sized bird is tested. 40g seems too less.
- OT A conspiracy theory might be is that HAL is intentionally bringing the dirty linen in public as forthcoming delays are imminent and now the canopy becomes an excuse to shadow the shortcomings in project management. Same thing happened with the altimeter/data link request and later the FOC was delayed.

putnanja · Post by **putnanja** » 19 Jan 2019 12:58

Dileep wrote:IR, Would there ever be an SQR that specifies the performance of the GRU in such detail (like max X degrees deviation during YYY degrees per second roll)? I guess not. Many of the demands are similar.

I am not sure if the increased canopy clearance is part of the current request. It was there at some point of time.

Another issue is, the HUD need to be tuned for the new canopy. There will be some very sour souls at Chandigarh for this.

If canopy height remains same and thickness of canopy is increased, the head clearance decreases! So I assume IAF is fine with it??

tsarkar · Post by **tsarkar** » 19 Jan 2019 14:43

Zynda wrote:How many instances of such a big bird striking fighters in India have happened? If there are strikes, what is the probability rate of such strikes? What is the mean time between such big bird strikes? Months, years? If it is quite rare like 1 in 100, then would such a rate justify a complete redesign, testing & certification of the canopy & associated underlying structures, further pushing FOC times?

The quoted part is a very Corporate Office based Executive Assistant/Management Consultant approach without understanding field operational aspects. No offence intended, Zynda Ji

but that is how IAS / Management works

To make it absolutely clear, I don't know the stats or accurate answer to any of the above. It is possible that IAF has indeed such data & their request could be based on such, in which case, I stand correct and tender an advance apology to Air Force folks

Kindly read up citations posted by Rakesh & Shiv in Military Flight Safety / IAF / Military Aviation thread. There has been multiple instances of Su-30, Mirage 2000 and MiG-29 suffering cockpit bird hits and bloodied and blinded pilots doing dead reckoning landings. Rakesh has posted atleast 5-6 such reports in the last 3 years

Part of the problem is environmental. Most airbases that 30-50 years ago were remote but now have population growth due to 1. Peripheral Support Infrastructure (stationery shop wala for school kids of Air Force personnel) 2. Retired other ranks settling in vicinity of airbases. So there has been huge population growth and consequently garbage is generated. In India public hygiene awareness is abysmally low and local civic body awareness lower. Cities like Bangalore and Bombay can’t manage garbage. This results in rodents feeding on garbage and larger birds (Brahminy Kites, Shikra) feeding on rodents. These birds can fly at aircraft heights and cause hits.

Singha · Post by **Singha** » 19 Jan 2019 16:52

Neshant wrote:
A lot of people in management have never risen to that rank by developing / inventing anything.

That is one of the biggest problems in management today.

Itvity is full of such managers. They are responsible for a lot of chaos and issues in product cos

Bala Vignesh · Post by **Bala Vignesh** » 19 Jan 2019 17:25

gaurav.p wrote: - regarding the updates on canopy is sad and shouldn't it be 400g rather than 40g? The testing videos on youtube seems a chicken sized bird is tested. 40g seems too less.

Gaurav,
That is an interesting bar graph!!! Thanks for sharing the same.

On the G ratings mentioned above,I think it's more of an acceleration figure, like 8G/-2G, than the weight of the bird as such.

Zynda · Post by **Zynda** » 19 Jan 2019 17:53

tsarkar wrote:The quoted part is a very Corporate Office based Executive Assistant/Management Consultant approach without understanding field operational aspects. No offence intended, Zynda Ji but that is how IAS / Management works

No offence taken tsarkar Sir. But my statements were not made from any of the management roles you mentioned but how design cases for some structural & fatigue analysis are arrived in real engineering.

There has been multiple instances of Su-30, Mirage 2000 and MiG-29 suffering cockpit bird hits and bloodied and blinded pilots doing dead reckoning landings. Rakesh has posted atleast 5-6 such reports in the last 3 years

This results in rodents feeding on garbage and larger birds (Brahminy Kites, Shikra) feeding on rodents. These birds can fly at aircraft heights and cause hits.

Thanks for posting this. It is possible bird strikes from larger birds are indeed an issue enough to concern IAF & hence the request.

gaurav.p · Post by **gaurav.p** » 19 Jan 2019 18:48

On the G ratings mentioned above,I think it's more of an acceleration figure, like 8G/-2G, than the weight of the bird as such.

Ah, my ignorance in domain knowledge is evident from my question. But I am just a

Thanks Bala vignesh ji

deejay · Post by **deejay** » 20 Jan 2019 00:00

Zynda wrote:
tsarkar wrote:The quoted part is a very Corporate Office based Executive Assistant/Management Consultant approach without understanding field operational aspects. No offence intended, Zynda Ji but that is how IAS / Management works
No offence taken tsarkar Sir. But my statements were not made from any of the management roles you mentioned but how design cases for some structural & fatigue analysis are arrived in real engineering.

There has been multiple instances of Su-30, Mirage 2000 and MiG-29 suffering cockpit bird hits and bloodied and blinded pilots doing dead reckoning landings. Rakesh has posted atleast 5-6 such reports in the last 3 years

This results in rodents feeding on garbage and larger birds (Brahminy Kites, Shikra) feeding on rodents. These birds can fly at aircraft heights and cause hits.
Thanks for posting this. It is possible bird strikes from larger birds are indeed an issue enough to concern IAF & hence the request.

Are bird strikes common in flying in India skies?

Bird hits are very common in India. Bird hits are very dangerous at low levels. Ingestion inside engines are obviously dangerous and so is canopy hits but even airframe damage alters flight characteristics including straight and level flight and landing speeds.

High flying migratory birds are a danger but so are a pack of small birds. Mostly, we try to avoid open garbage dumps close to airports and specially on take off / approach cone.

All those who have observed flying at HAL airport will see bird scarers / chasers deployed along the length of the runway through the day bursting (Diwali firecrackers) small bombs to scare away birds.

Civil airports employ sound guns and other measures similar to military airports.

disha · Post by **disha** » 20 Jan 2019 07:04

gaurav.p wrote: - some harsh criticism by an IAF veteran (I don't concur with it, but then I might be wrong) Link 1 Link 2

Doubt the above criticism is from "IAF veteran", sample this in the criticism:

DRDO and HAL are leeches sucking IAF and govt funds and only bloating with no accountability.

On internet, you do not know if the other side is a human or a dog or a pig.

deb_v · Post by **deb_v** » 20 Jan 2019 07:47

disha wrote:
gaurav.p wrote: - some harsh criticism by an IAF veteran (I don't concur with it, but then I might be wrong) Link 1 Link 2
Doubt the above criticism is from "IAF veteran", sample this in the criticism:

DRDO and HAL are leeches sucking IAF and govt funds and only bloating with no accountability.
On internet, you do not know if the other side is a human or a dog or a pig.

The gentleman who wrote the article in quora is most definitely ex IAF and is a very respected Mirage Pilot. It’s in poor taste to call him a dog / pig.

He is mentioned in a couple of places on this forum.

Singha · Post by **Singha** » 20 Jan 2019 08:50

Nevertheless whatever be the credentials , bs and smear tactics must be called out

That is the only way that truth values be kept

Bala Vignesh · Post by **Bala Vignesh** » 20 Jan 2019 10:28

His profile summary doesn't seem to indicate the kind of finesse seen profiles of AF personal. And if he is one, the tone and the tenor of the comments are very off for such a senior person.

hnair · Post by **hnair** » 20 Jan 2019 11:08

A rant is a rant. Same as how this forum dissected that other AVM who has a name similar to sardine fish in malayalam, when he ranted about LCA, we should not hold back for this gent too

What is he trying to tell the Indian taxpayer? “Cough up, cough hard and die?” because that is what millions of Indians have done during peace time

These senior Air Force gents don’t realize the key point that 1000s of Indian civilians die during peacetime due to lack of money for vital nutrition and medical programs, so these senior guys can order shiney foreign gear for use during war time and protect our way of life. And since this gent talks about track records, IAF dominance over western side was never overwhelming and decisive despite all foreign gear they ordered in past. Navy on the other hand, ruled the waves in all wars and they don’t whine like these about their programs!

So when a civilian hears these senior guys shedding crocodile tears about track record of Indian R&D and at the same time pissing on the success of a creditable program like LCA, what should one feel?

Chap even pissed on a towering gent like Kalam-sahib’s memory despite his only claim to comment on Indian R&D is that he apparently drew on a napkin, where five MFDs should go

PratikDas · Post by **PratikDas** » 20 Jan 2019 11:50

Tejas - LCA's Post

14th series produced Tejas, LA - 5014 had her maiden flight yesterday. The 13th member will follow soon. The competition between the two assembly hangars is intensifying. Competition, in one sense, indicates better days are ahead.

https://www.facebook.com/tejas.lca/posts/2104763666284737

Karan M · Post by **Karan M** » 20 Jan 2019 12:03

Gaurav, I would take AM Nambiar, a serving IAF Mirage 2000 vereran who is the VCAS, and his evaluation of the LCA today anyday over the recollections of an individual who is still caught up in agency politics of decades past. With all due respect to this veteran, he is almost completely mistaken about what is within the LCA and is repeating the same canards about imports etc. For reference, he quotes events dating from the early-mid 80s.

We don't have time or the mindspace to sit and give every person who fell by the wayside of a tough development program, a place to sit and vent about why they weren't given their day in the Sun or how the program didn't shape up their expectations at that point in time.

Tough luck, but the program has moved on, with or without them. The same is the case with many academic profs from the civil side who keep complaining about the LCA, even as it adds more hours to it's belt.

National programs come first, personalities next and thankfully, with Akash, LCA, Arihant etc we are now demonstrating that irrespective of the critics we take complex programs to completion.

Karan M · Post by **Karan M** » 20 Jan 2019 12:22

deb_v wrote:
disha wrote:
Doubt the above criticism is from "IAF veteran", sample this in the criticism:

On internet, you do not know if the other side is a human or a dog or a pig.
The gentleman who wrote the article in quora is most definitely ex IAF and is a very respected Mirage Pilot. It’s in poor taste to call him a dog / pig.

He is mentioned in a couple of places on this forum.

Agree. No more name calling please.

Echo HNair, please call out his biased views by all means, but without resorting to such methods.

The Quora gents name calling of national orgs may incite members. Don't fall prey to emotions and please rebut dispassionately. He is a veteran, has served, let's take the high road as much as possible.

gaurav.p · Post by **gaurav.p** » 20 Jan 2019 13:01

Karan M wrote:Gaurav, I would take AM Nambiar, a serving IAF Mirage 2000 vereran who is the VCAS, and his evaluation of the LCA today anyday over the recollections of an individual who is still caught up in agency politics of decades past. With all due respect to this veteran, he is almost completely mistaken about what is within the LCA and is repeating the same canards about imports etc. For reference, he quotes events dating from the early-mid 80s.

We don't have time or the mindspace to sit and give every person who fell by the wayside of a tough development program, a place to sit and vent about why they weren't given their day in the Sun or how the program didn't shape up their expectations at that point in time.

Tough luck, but the program has moved on, with or without them. The same is the case with many academic profs from the civil side who keep complaining about the LCA, even as it adds more hours to it's belt.

National programs come first, personalities next and thankfully, with Akash, LCA, Arihant etc we are now demonstrating that irrespective of the critics we take complex programs to completion.

Yes Karan ji I am always pro-tejas in this aspect. Even if it won't have the latest IRST, EO/IR and what not glittery things, it is indigenous. Even if one compares it with some 3rd gen or 5th gen it doesn't matter. The MIC is what matters. Nobody is going you to serve technologies on platter. The ecosystem being created is the main takeaway.

I just wanted to just highlight the comment from a decorated IAF veteran. If it is the case of identity theft, then the whole brf database can be impersonated and it is a possible threat. If it is not then all I can say is goodluck and back off. Futile to change biases and prejudices. Keeping the brickbats and the proving the critics wrong is the key here.

Tejas is not being sold with the glitter and shine as of now compared to some weedish maal because the domestic demand is much more. And one shouldn't care about d**k measurement contests. The overexageration of deficiencies by CAG, or snags during gaganshakti are nothing but hitjobs being done who have no skin in the game. Majority journalists make a living by cribbing and complaining as that is what sells. They are just playing a leg pulling contest. People don't know about yaw, pitch, roll and go on criticising the aerodynamics of the plane + giving unnamed quotes. People don't know the dimensions of the plane and go on wanting everything fitted into it. This thinking of 'sab chaiye' is nothing but waste of time. I am not involved in Tejas program but consider me another unooficial cheerleader of tejas. Forever.

."First they ignore you, then they laugh at you, then they fight you, then you win."

Currently the laughing post FOC is decreased and are fighting to displace the radiance. The last lap is the most important one, need to keep the fire burning and keep moving forward.

Karan M · Post by **Karan M** » 20 Jan 2019 14:23

This gentleman's issues re: bias can clearly be seen from this excerpt.

As the most experienced pilot on the Mirage 2000- 1st France batch-I was deputed to ADA for 8 months at ADA under Dr Kota Harinarayan, an offr I had trained on cockpit layout, emergencies and cockpit management on the MiG-21 bis in early 1977.

I worked along with Ex IAF Sqn Ldr Vishwesharaya and under Rear Adm Chatterji?. Along with a MiG-29 pilot, S/L Sebastian, we designed the cockpit interface, focussing on a 5 MFD glass cockpit. Our work was appreciated. Sadly, internal politics sabotaged the LCA. How could such a junior offr like Dr Kota be made Director ADA ahead of old timers like Dr KG Krishna? I saw great resistance here.

He still can't get over the fact that he was reporting to a junior person whom "he trained". To buttress that he brings up KGN etc. And then adds:

Interestingly, KG’s wife was my classmate!

Yes, no bias there at all.

I saw a lot of French and Swedish individuals helping out on the LCA. Dassault had taken up the FBW system and the Swedes the RBO-5 radar.

And then mentions nothing came of it, so why state it, if not to imply good for nothing Indians didn't do anything? In real life, Dassaults FBW proposal was rejected and we didn't work with the Swedes either.

And of course

Apart from a core group of 60 odd professionals, the remaining 240 odd were in only to get a free 3-month trip to France.

He was of course present in each meeting, discussion, training with all these remaining 240 odd people to so confidently state they were all useless and only out on a trip. After the event, he even polled these guys to get accurate information on what was what.

Seriously, if anything smacks of elitist bias it is this. I have seen much of the same attitude in people in private orgs who sneer at juniors getting a trip abroad, to which only they being senior and capable, are entitled to. Nobody else should be allowed to enjoy these "perks". Luckily org managements are quite capable of realizing how broad basing skills helps orgs versus letting it remain in the hands of a few "seniors".

quote]Add that to development costs, which I believe has crossed US$10 billion. If HAL has to make a profit by selling these ac, ALL costs must first be met.
[/quote]

Does he even realize bulk of the costs were met by grants to ADA and not HAL and ADA is a not for profit GOI agency?

Low AR winged ac have very poor tolerance of prevailing turbulence, high overall drag increasing fuel consumption, very high initial turn performance, poor sustained turn performance where drag rises very rapidly and cannot be countered by engine thrust, etc. Low speed performance is poor and they are prone to deep stall, though they rarely enter a spin

All things said for his beloved Mirage 2000 as well, word to word by afficianados of competing platforms citing one or the other Cherry picked aero/subjective parameter "delta wing", "early gen turbofan engine", "too delicate", ...and yet it stands tall.

The dear gentleman is victim of certain biases.

Austin · Post by **Austin** » 20 Jan 2019 14:33

Low AR winged ac have very poor tolerance of prevailing turbulence, high overall drag increasing fuel consumption, very high initial turn performance, poor sustained turn performance where drag rises very rapidly and cannot be countered by engine thrust, etc. Low speed performance is poor and they are prone to deep stall, though they rarely enter a spin

So if that is the quality of Low Aspect Ratio Wing AC which must be true for Mirage or other Delta platform , How do they get over this by using FBW and High Thrust Engine or they prefer to fight at high altitude where they can take advantage of Delta platform ?

I recollect even M2K was criticised for its thrust issue and Dassault came up with twin engine Mirage 4000 which never saw the light of the day

Karan M · Post by **Karan M** » 20 Jan 2019 14:51

The Mirage 2000 does not apply, its French, not made by stupid Indians.

Anyways.

https://www.grc.nasa.gov/www/k-12/airplane/induced.html

For a non conventional take..

Why Aspect Ratio Doesn't Matter.
https://bigsynthesis.com/understandinga ... n-t-matter

http://www.defense-aerospace.com/articl ... mpare.html

Basically, for the same wing area, a low AR will have higher induced drag than high AR. However, where in which place is the LCAs wing area the same as that on it's peers?
With a HMS and ASRAAM/R73E good luck in attacking the LCA in WVR and then pondering about aspect ratio.

With the RD-93 vs Ge404, go ahead and compare the engines and then wonder which affects range more, the fuel payload and engine or Gyan about one ratio or the other.

Seriously, more I see these guys attacking the LCA as it's being inducted, more I appreciate what the LCA guys had to overcome.

Gyan · Post by **Gyan** » 20 Jan 2019 17:38

Another view of the modern dog fights is that a fighter aircraft never gets an opportunity for full/complete turns and it's more like a slash attack, where Delta wing dominates due to high ITR. Israel used this strategy with Its Mirages.

Gyan · Post by **Gyan** » 20 Jan 2019 17:44

Did anyone notice reference to Kalam interest in Astra missile in 1988???

Though even I have seen first pics of the initial design by 1994.

prasannasimha · Post by **prasannasimha** » 20 Jan 2019 17:46

SP14 had its maiden test flight. SP13 to follow. SP 14 flew before 13

SriKumar · Post by **SriKumar** » 20 Jan 2019 21:25

Seriously, more I see these guys attacking the LCA as it's being inducted, more I appreciate what the LCA guys had to overcome.

Once you have your own design (and manufacturing process), you practically have the power of God* in your hands with regards to the craft. It is a boon to the IAF, really. Some dont realize this, others probably do- those who've flown the planes and asked for changes and gotten them. No export will come close to this. This aspect (i.e. making design changes to suit your needs) could be misused to create delays, but a very powerful foundation is being set with the current work.
*God= Vishwakarma

FIrst squadron almost there (barring trainers, with SP14 flown and SP13 close to follow).

JayS · Post by **JayS** » 20 Jan 2019 23:30

prasannasimha wrote:SP14 had its maiden test flight. SP13 to follow. SP 14 flew before 13

From two different lines.

JayS · Post by **JayS** » 20 Jan 2019 23:40

Dileep wrote:IR, Would there ever be an SQR that specifies the performance of the GRU in such detail (like max X degrees deviation during YYY degrees per second roll)? I guess not. Many of the demands are similar.

I guess not too. The Q in SQR is called "Qualitative" for a reason. Specifics to this level should be part of Standards such as Mil or similar and should be in Certification domain rather than Customer requirement really. Of coarse IAF (because they have real life operational data) would work with CEMILAC and ADA in defining the standards and certification requirements. But IAF is not really the one in best situation to decide upon technical specifics.

Austin · Post by **Austin** » 20 Jan 2019 23:54

Karan M wrote:Seriously, more I see these guys attacking the LCA as it's being inducted, more I appreciate what the LCA guys had to overcome.

True , Tejas was almost slow sabotaged by IAF and put on backburner for their next imported favorite toy till Parikar came into the picture and forced reviewed it.

JayS · Post by **JayS** » 21 Jan 2019 00:11

tsarkar wrote:
Zynda wrote:How many instances of such a big bird striking fighters in India have happened? If there are strikes, what is the probability rate of such strikes? What is the mean time between such big bird strikes? Months, years? If it is quite rare like 1 in 100, then would such a rate justify a complete redesign, testing & certification of the canopy & associated underlying structures, further pushing FOC times?
The quoted part is a very Corporate Office based Executive Assistant/Management Consultant approach without understanding field operational aspects. No offence intended, Zynda Ji but that is how IAS / Management works.

Actually Sir, this is exactly how a design criteria shoukd be decided upon. And no, managers dont talk like this, this is very much like what a Engineer should thing like. And this kind of uestion seeks the right kind of real life data to base the technical criteria upon rather than based on some unrealistic theoretical stuff.

I was reading a document from DTIC a couple of days ago on design criteria for canopy for bird strike. The paper compiled data on as many reported bird strikes with as many associated parameters such as segment of flight, speed, location, altitude, type and weight of bird, where on aircraft the impact happened and so on. Aditionally it has data on occurence of a lage number of birds across the USA, over hundred pages on data only on birds. Then the author went on to define predictor models based on this data and then the design criteria. This is how it should be. Its easy to go way off the mark and end up overdesigning or underdesigning if the design criteria is not realistic. A significant part of what we call as "Technology" is to know what to design for. We have n number of situations in our programs where lack of knowledge on precisely this matter has given us a lot of heart ache e.g. LCA FCS redundancy testing, NLCA MLG design, RustomII safety factor and so on.

I see how many large size birds keep flying around HAL airport on daily basis. From some of the data I saw (US related), canopy has about 20% chance of bird hit, rarely more than 4lb sized bird, and nearly 70% bird hits are during TO or Lnading where they are more leathal for obvious reasons. The hits on canopy can be rather serious and are typically ranked below bird sucking in engines. So I think IAF is well within their rights to ask for mods. However I wonder why now? So late in the program..? The issue with bird strikes is well know since like foreever. Its a critical safety requirement and should have been enforced early in the program. Also I wonder how other fighters comply if IAF brought this out only now for LCA. Clearly other fighters couldnt have, if IAF only recently thought of hiking safety criteria. And if they already knew and other fighters do comply then why such late popping up of this in LCA program..? Does even Rafale comply with this..? I wonder.

PS - 1 in 100 is not rare by Aerospace design standard. Even if its as low as 1 in 1000000, its a valid case for considering for design IMO. Anything lower than that can be aceeptable risk. Because the FoS on design wpuld give sufficient margin to counter that one off case and at the same time design for too rare event would not penalize the designed component unnecessary. Untimately, no design is foolproof. One has to go by what is acceptable risk and what is not. Make it too conservative and aircrafts will become so heavy they will never be able to fly, or too expensive.

fanne · Post by **fanne** » 21 Jan 2019 01:04

Low AR winged ac have very poor tolerance of prevailing turbulence, high overall drag increasing fuel consumption, very high initial turn performance, poor sustained turn performance where drag rises very rapidly and cannot be countered by engine thrust, etc. Low speed performance is poor and they are prone to deep stall, though they rarely enter a spin

Low AR (like in Mirage 2000 and LCA) have high initial turn performance and hence you can device tactics like slash and run. However, the good officer is being economical with the fact on poor sustained rate, it is true for older mirages (Mirage III and V), but the unstable config in the horizontal axis resolves this problem. Both MIRAGE 2000 andl LCA are that (LCA being more unstable per chaiwala). When turning the musharaff of older mirages (low aspect a/c with stable config) is higher than the nose, killing lift and bleeding speed, while in case of Mirage 2000 and LCA, the nose is high, sustaining that intial energy. It is not an issue.

As being pointed out, LCA is a success, too bad, people less smarter than you or less capable or less endowed did that. It is here, present and fufilling our need. Get on with this fact and please stop cribbing.

JayS · Post by **JayS** » 21 Jan 2019 01:16

Karan M wrote:
For a non conventional take..

Why Aspect Ratio Doesn't Matter.
https://bigsynthesis.com/understandinga ... n-t-matter

http://www.defense-aerospace.com/articl ... mpare.html

Basically, for the same wing area, a low AR will have higher induced drag than high AR. However, where in which place is the LCAs wing area the same as that on it's peers?

.

Low AR == high drag and so on, kind of half baked aerodynamic knowledge comes from taking text books too seriously. Text books have a way of simplifying things for easy understanding. But if one takes the simplified picture too literally one could end up in such limited understanding of a subject (majority folks fall for this, including me). Today all military fighters are low AR aircrafts with half of them delta wing or almost delta wing config. Even common sense should tell one if low AR was such bad thing, we would have seen all 2D rectangular wings today.

disha · Post by **disha** » 21 Jan 2019 10:16

deb_v wrote: The gentleman who wrote the article in quora is most definitely ex IAF and is a very respected Mirage Pilot. It’s in poor taste to call him a dog / pig.

No sir, I clearly said that the gentleman does not appear to be ex-IAF since the said poster on quora made unprofessional statement.

Second point is on internet you cannot believe everybody who claims to be one.

If you do not know the meme I was talking about., please read this https://en.wikipedia.org/wiki/On_the_In ... 27re_a_dog or understand this article https://web.archive.org/web/20171229172 ... ernet.html

Instead you have twisted my statements. And definitely did not understand the extension of the meme. If you definitely (and 100% beyond reasonable doubt) think that the said poster on quora is an ex-IAF then so-be-it, others members have already dissected that said poster. You cannot force me to accept that the said poster on quora is *definitely* an ex-IAF.

I have interacted with ex-IAF/ex-Army (wing-Co/3* general) and in the most heated of discussions they never behaved unprofessionally. And BTW my own uncle worked in KH's team and even though there were professional misgivings and rivalry, there was no out of character rant in private or public forums. My uncle's biggest "rant" if ever one calls it as such, was to see LCA weaponized & inducted and he knew that in his own lifetime (having suffering from terminal illness) he will not see it.

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I have a theory, Desis are tactically smart (brilliant) but strategically stupid. We love to highlight our own misgivings as major shortcomings and air it publicly and do rona-dhona like there is no tomorrow.

Like you aspire for Jockey or Polo chaddi-baniyan but can only settle for Rupa or Vijay and then go all over the internet airing how cheap and how smelly the unwashed underwear is. Of course both are true statements!

Indranil · Post by **Indranil** » 21 Jan 2019 10:33

These kind of rants can’t be taken seriously. My knowledge in aeronautics is half-baked, but such blanket statements is quite naive. As Jay says, if deltas are bad, all the Eurocanard, J-10/J-20 designers are pretty inept at their job.

JTull · Post by **JTull** » 21 Jan 2019 15:27

Locked on to future, Sulur emerging as IAF's key base - By Anantha Krishnan M