Indian Military Aviation- September 29 2013

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Re: Indian Military Aviation- September 29 2013

Postby jamwal » 03 Jun 2014 18:12

rrao,
Take a screenshot instead of taking picture of screen with a camera.

http://www.wikihow.com/Take-a-Screensho ... ft-Windows
http://www.take-a-screenshot.org

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Re: Indian Military Aviation- September 29 2013

Postby Austin » 04 Jun 2014 15:06


shiv
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Re: Indian Military Aviation- September 29 2013

Postby shiv » 04 Jun 2014 17:38

rrao wrote: i was wondering what is basically wrong with the IJT


As far as my knowledge goes the IJT, provided the Russians have sorted out the engine - is fine for many aspects of initial jet training. However it is not yet proven for stall and spin recovery training. So far it has been flown only by test pilots and there have been 3 incidents/accidents. Two involved the late Baldev Singh - including an incident at Aero India when the canopy was not locked and it flew off. I think the plane itself was recovered in both these instances.

The most serious incident was a crash in which both pilots bailed out and IIRC that crash had something to do with the Al 55 engine - maybe someone who remembers the details can correct or corroborate. It was after that incident that we saw a clampdown on news until now - we suddenly see 6-7 IJTs in a photo.

As I said - the plane does fly and I think there is even a simulator for it (I have flown that simulator for a few minutes)
http://www.youtube.com/watch?v=KFjX3d1nwPU

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Re: Indian Military Aviation- September 29 2013

Postby Austin » 04 Jun 2014 18:17

IIRC the single IJT crash was attributed to pilot putting the IJT into High AoA or Spin/Stall and could not recover from it , which subsequently lead to stopping of IJT flights.

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Re: Indian Military Aviation- September 29 2013

Postby rrao » 04 Jun 2014 18:42

shiv sir, Thats very nice video of IJT during Aero India show. The IJT looks deceptively small, but actually its as big as the Hawk... Two accidents, aircraft survived and the third one aircraft perished and as far as the tragic fourth one Late Baldy sir left for an untimely heavenly abode!!! Austin sir you are spot on!!! I too heard the same thing!!!

why cant scaled down RC models of IJT,LCA and SARAS be made and flight performance to some extent be evaluated? The YAK130 with micro turbo engines resembles the original one!!! companies like TAAL, NAL and IITs and university students can make these RC planes...of course making them is not an easy one with available tech resources!!!





P.S : i came across one youtube video of LCA RC plane made by IISc students!!!

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Re: Indian Military Aviation- September 29 2013

Postby vsunder » 04 Jun 2014 19:36

@rrao. This is not a new idea for India. In fact the legendary designer Kurt Tank built full scale glider models that he flew himself for almost anything he designed. He built a full scale glider model of the HF-24 that he wanted to fly himself over the Bangalore skies, much to the astonishment of HAL engineers, who tried to dissuade him from flying the plane himself. The argument was if Tank died there would be none to continue the project. Eventually Tank relented. 1:10 scale models were also tested in the IISc wind tunnels for low speed handling, while at high speeds I think V.M. Ghatage had to go to Switzerland(??) to use wind tunnels there. I have photographs of this HF-24 glider flying. In fact some of you may have the entire chapter with many photographs, abstracted from a large book on Kurt Tank. I recall several of you asked me for a scan of the chapter of Kurt Tank in Bangalore. I suppose computational power has reached the point when people feel more confident with numerical simulation.
Last edited by vsunder on 04 Jun 2014 19:53, edited 3 times in total.

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Re: Indian Military Aviation- September 29 2013

Postby shiv » 04 Jun 2014 19:40

Austin wrote:IIRC the single IJT crash was attributed to pilot putting the IJT into High AoA or Spin/Stall and could not recover from it , which subsequently lead to stopping of IJT flights.


Wasn't this because of engine packing up or some such thing?

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Re: Indian Military Aviation- September 29 2013

Postby NRao » 04 Jun 2014 19:51

I suppose computational power has reached the point when people feel more confident with numerical simulation.


That is what a "5th Gen" plane is. A mathematical model that is designed to reflect very little and (nearly as an after thought) is able to fly. Much as the F-16 was a "brick" that flew.

That said, I am not sure where India stands in this world. But, I am fairly confident they are not shabby - to say the very least.

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Re: Indian Military Aviation- September 29 2013

Postby vsunder » 04 Jun 2014 19:59

@Nrao: That is what I was saying earlier, transmission eigenvalues, "reflects very little" all EM waves gets transmitted, little scattering. Eigenvalues are the frequency if you wish of the scanning radar.
USAF is dumping lots of money for this sort. No India in CFD is not shabby, but various groups do not talk to one another, that is the rub.

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Re: Indian Military Aviation- September 29 2013

Postby Philip » 05 Jun 2014 09:53

Funny.If the IJT survives and is passed by the IAF,it will further validate Russian engines,which many have tried to discredit despite they being used and manufactured for the MIG-29,MKIs,etc. without any problems! If it is dumped,and there is a possibility that it may happen if by Dec. IOC isn't attained,it will be a major setback for HAL. It will also bring into Q HAL's ability to deliver on its share of the FGFA,if it is both cash strapped and (human) resource strapped. Some time ago,due to the shortage of HR,the IJT team was double tasked with that of the FGFA! If it is dumped,what should our plan "B" be? Whom have the IAF shortlisted?

The priorities for HAL should firmly be on the the LCA,getting MK-1 with its underpowered GE engine for which 40 have been ordered in to series production asap,as we are told that the definitive production version is nearing completion,all prototypes thus far differ from each other to an extent.Another 40MK-1s should be ordered,so that there is a long run until the definitive Mk-2 with its more powerful engine (hopefully,if it doesn't also put on too much extra weight) also enter series production. One would still like to see the GOI/MOD build extra prototypes of MK-2 with alternative engines (EJ,SNECMA,whatever) just in case the 414 fails to deliver after the modifications to Mk-1.Increased production rates may also require a second manufacturing centre,esp. if the MMRCA fructifies and HAL will be overwhelmed with aircraft orders for new aircraft plus upgrades.

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Re: Indian Military Aviation- September 29 2013

Postby Kartik » 05 Jun 2014 10:06

Philip wrote:Funny.If the IJT survives and is passed by the IAF,it will further validate Russian engines,which many have tried to discredit despite they being used and manufactured for the MIG-29,MKIs,etc. without any problems! If it is dumped,and there is a possibility that it may happen if by Dec. IOC isn't attained,it will be a major setback for HAL. It will also bring into Q HAL's ability to deliver on its share of the FGFA,if it is both cash strapped and (human) resource strapped. Some time ago,due to the shortage of HR,the IJT team was double tasked with that of the FGFA! If it is dumped,what should our plan "B" be? Whom have the IAF shortlisted?



wait wait..so if the IJT makes it, it will validate Russian engines ?! The MTBO of the Al-55I is in the lower hundreds and you're telling us that entering service will validate Russian engines? What about the delays it has caused, which I've never seen you criticise while you rail against HAL on other aspects? What about the fact that the IAF will NEVER accept the IJT as long as the Al-55I has such pathetic overhaul requirements ??

if it is dumped, the lion's share of the blame will go to the rather poorly thought-out decision to go for the totally unproven Russian engine and an substantial portion of the blame will also be apportioned to the Russian side for the delays and the rather unbelievably poor and low MTBO specs.

So if it makes it, credit to the Russians, if it doesn't blame HAL for a poor design. Nice.

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Re: Indian Military Aviation- September 29 2013

Postby RKumar » 05 Jun 2014 12:28

Philip wrote:One would still like to see the GOI/MOD build extra prototypes of MK-2 with alternative engines(EJ,SNECMA,whatever) just in case the 414 fails to deliver after the modifications to Mk-1


:eek: :eek: :eek:

:rotfl: :rotfl: :rotfl:

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Re: Indian Military Aviation- September 29 2013

Postby shiv » 05 Jun 2014 19:01

Here is the story of a plane that rolled before stalling because one wing stalled before the other
http://www.ntsb.gov/doclib/reports/2012/AAR1202.pdf
Gulfstream did not determine (until after the accident) that the cause of two previous uncommanded roll events was a stall of the right outboard wing at a lower - than - expected AOA. (Similar to the accident circumstances, the two previous events occurred during liftoff ; however, the right wingtip did not contact the runway during either of
these events.)

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Re: Indian Military Aviation- September 29 2013

Postby Indranil » 05 Jun 2014 19:45

Ah! Excellent find Shivji. This explains a lot.

I havn't had the time o read the entire article but I may have got the gist, and it explains the modifications that I see in the IJT. I was always thinking of about asymmetry, never thought that there might be premature stalling of one of the wings before the designed critical angle. I think HAL was also thinking on the same lines and introduced the nasal strakes, dorsal fins and wing fences to handle asymmetry.

But in the latest pictures brought to us by Ajai Shukla, the nasal strakes and wing fences have been removed. And modifications have been made to the wing (vortex generators have been added) to delay the stalling of the wing.

May be. I am not sure though :|

Click for higher resolution
Image

Image

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Re: Indian Military Aviation- September 29 2013

Postby Rahul M » 05 Jun 2014 19:48

how does one wing stall before the other ? aren't they symmetric ?

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Re: Indian Military Aviation- September 29 2013

Postby Mihir » 05 Jun 2014 20:12

It was a common problem on the MiG-15. Yefim Gordon's history of the aircraft had some interesting details about it. It's been a while since I read it, so I'm quoting from memory, but the Russians realised very quickly that when it came to swept wings, the two wings had to be exact mirror images of each other to avoid wing-drop. The manufacturing techniques of the time lacked the precision needed to make this happen, so they had to develop newer technology.

Of course, this doesn't explain why the problem exists with the IJT...

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Re: Indian Military Aviation- September 29 2013

Postby shiv » 05 Jun 2014 21:16

indranilroy wrote:Ah! Excellent find Shivji. This explains a lot.

Confession. I did not find it - the link was sent to me by another forum member and I didn't bother to ask him permission before posting it here.

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Re: Indian Military Aviation- September 29 2013

Postby vic » 05 Jun 2014 22:01

I wonder if somebody remembers the bizarre theories and chest beating about the incompetence of ISRO when ASLV failures occured. But ISRO went on to develop PSLV without getting bogged down in ASLV, which was also perfected.


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Re: Indian Military Aviation- September 29 2013

Postby Indranil » 06 Jun 2014 01:07

Mihir wrote:It was a common problem on the MiG-15. Yefim Gordon's history of the aircraft had some interesting details about it. It's been a while since I read it, so I'm quoting from memory, but the Russians realised very quickly that when it came to swept wings, the two wings had to be exact mirror images of each other to avoid wing-drop. The manufacturing techniques of the time lacked the precision needed to make this happen, so they had to develop newer technology.

Of course, this doesn't explain why the problem exists with the IJT...

That's what I know too.

Actually, the more I think, the more convinced I become that the "inherent design flaw" is that the washout in the IJT wings is not enough to reduce the severity of the wing drop. This is what they wanted to fix with a long wing fence first (on PT-2). That would have delayed the stalling of the wing tip, but would have actually increased the steep stall characteristic. So now, they are trying to make the propagation of the stall more gradual. The long wing fence is gone, and the vortex generators have been introduced in front of the aelirons.

I think they are inching towards a solution.

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Re: Indian Military Aviation- September 29 2013

Postby shiv » 06 Jun 2014 06:22

I find it odd that we simply take for granted (as accurate and true) one news item that says there is an inherent design flaw without asking for more information. In any other field outside a random Internet forum such a conclusion would outright be acknowledged to be nonsense.

On a forum such as this it is OK to make solid theories out of incomplete bits of information. But after a while readers (lurkers and forum members) of theories cooked up from incomplete information internalize those theories as the truth - which it simply cannot be in the absence of more information. I would simply wait and see what turns up in terms of developments.

Meanwhile, please ignore this post.

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Re: Indian Military Aviation- September 29 2013

Postby Singha » 06 Jun 2014 07:36

mission briefing during Garuda V

Image

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Re: Indian Military Aviation- September 29 2013

Postby rrao » 06 Jun 2014 10:42

Another good news!!! EMC tests as per mil-std-464 have been completed on IJT LSP-3!!!!

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Re: Indian Military Aviation- September 29 2013

Postby Rahul M » 06 Jun 2014 11:30

thanks vic. so if the news of asymmetric wing stall is correct, the likely cause is differential use of ailerons ?
the other reasons, (pax more on one side, ice formation etc are not that likely IMO)
I doubt the the wings themselves are so asymmetrically made that they lead to one stalling before the other.

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Re: Indian Military Aviation- September 29 2013

Postby Shreeman » 06 Jun 2014 12:09

Rahul M wrote:thanks vic. so if the news of asymmetric wing stall is correct, the likely cause is differential use of ailerons ?
the other reasons, (pax more on one side, ice formation etc are not that likely IMO)
I doubt the the wings themselves are so asymmetrically made that they lead to one stalling before the other.


Dont the wings have to stall at different times for a spin to occur, otherwise only the nose will dip and then no stall? Wasnt the problem the roll, not the wing stall? Surely, simulation and modeling can predict passanger weight level issues?

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Re: Indian Military Aviation- September 29 2013

Postby Bhaskar_T » 06 Jun 2014 13:13

Tarmac/Indian express reporting "MiG 29K suffers damage on board Vikramaditya". :(

(Quote) - A MiG 29K naval combat aircraft has suffered damage while landing on the aircraft carrier INS Vikramaditya during operations in Arabian Sea off the coast of Goa, a navy official said on Thursday.
The Russian-make aircraft had taken off from the naval airbase INS Hansa in Goa on Wednesday and hard-landed on the aircraft causing damage to the nose-wheel undercarriage, the official said.
The pilot of the aircraft is safe and further details of the damage are being assessed, they said.
The Navy has ordered a Board of Inquiry (BoI) into the accident on the aircraft carrier procured from Russia at a cost of over Rs 15,000 crore late last year.
In this mishap on-board the 44,500-tonne warship, the pilot missed the first two arrester wires used as aid for landing on the carrier and while he was trying to take off again, it got stuck in the third arrester wire causing a hard-landing, navy officials said.
MiG 29Ks have been procured by India from Russia and India is the only country in the world which operate these twin engine naval fighters. India has ordered for 45 of these aircraft and this is the first accident involving these aircraft.
(Unquote)

Link - http://indianexpress.com/article/india/ ... ramaditya/

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Re: Indian Military Aviation- September 29 2013

Postby rrao » 06 Jun 2014 14:32

shiv wrote:I find it odd that we simply take for granted (as accurate and true) one news item that says there is an inherent design flaw without asking for more information. In any other field outside a random Internet forum such a conclusion would outright be acknowledged to be nonsense.

On a forum such as this it is OK to make solid theories out of incomplete bits of information. But after a while readers (lurkers and forum members) of theories cooked up from incomplete information internalize those theories as the truth - which it simply cannot be in the absence of more information. I would simply wait and see what turns up in terms of developments.

Meanwhile, please ignore this post.


Shiv saar !!! i have highest regards for the entire BRF, because it is frequented by veterans from all fields of military complex!!!! i have been seeing snide remarks of HAL,IJT,LCA,DHRUV for quite long time from some ill informed members. Hari Nair sir gave back sharply defending Dhruv performance in siachen in another forum. when i read reports of IJT is bad ,i was literally wondering what could be bad about IJT. Some Jurnos news/ reports have always been critical and you know why!! Addition of strakes and vortex as observed by Indranil ,later removal of strakes suggests the correctness of the news report. you have given a very good link which explains unintentional roll issue and others too have expressed possible causes. The forum thinking and ppl at IJT design centers possibly are thinking on similar lines and HAL is inching closer to resolving the issue!!!!Thats a wonderful sign!!!

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Re: Indian Military Aviation- September 29 2013

Postby anand_sankar » 06 Jun 2014 14:39

Statistically fixed wing carrier ops have higher than average accident rates. Good to know this was just a minor mishap.

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Re: Indian Military Aviation- September 29 2013

Postby P Chitkara » 06 Jun 2014 14:54

Landing an aircraft on land is far, far easier than landing it on a carrier and one will find hence higher rates of incidents in all navies that operate STOBAR or CATOBAR carriers.

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Re: Indian Military Aviation- September 29 2013

Postby Shreeman » 06 Jun 2014 15:34

P Chitkara wrote:Landing an aircraft on land is far, far easier than landing it on a carrier and one will find hence higher rates of incidents in all navies that operate STOBAR or CATOBAR carriers.


These things happen.

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Re: Indian Military Aviation- September 29 2013

Postby shiv » 06 Jun 2014 15:54

rrao wrote: you have given a very good link which explains unintentional roll issue and others too have expressed possible causes. The forum thinking and ppl at IJT design centers possibly are thinking on similar lines and HAL is inching closer to resolving the issue!!!!Thats a wonderful sign!!!



The only question is "How true is that report about roll?". Is it true at all? Has anyone else corroborated it? Could this be yet another fake plant in the IJT versus import saga?

Has anyone actually spoken to people involved intimately or peripherally with the IJT program to confirm that this one single report is true?

It is important to get that right, or else we will be reaching conclusions and solutions for problems that have been misreported or even cooked up.

That is what I am getting at.
Last edited by shiv on 06 Jun 2014 15:58, edited 1 time in total.

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Re: Indian Military Aviation- September 29 2013

Postby shiv » 06 Jun 2014 15:58

About the NiG 29 on Vikramaditya, one report stated that after the hook missed the first two cables the pilots throttled up and started going nose up to take off and come around when the third cable caught and the nose wheel slammed down.

Yes. These things happen.

Flight sim buffs should try aiming for a landing on a carrier and see how much more difficult it is.

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Re: Indian Military Aviation- September 29 2013

Postby vic » 06 Jun 2014 16:47

I think we should work on parallel lines to IJT like HTT-40 and LCA Trainer AJT version.

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Re: Indian Military Aviation- September 29 2013

Postby deejay » 06 Jun 2014 17:42

The only question is "How true is that report about roll?". Is it true at all? Has anyone else corroborated it? Could this be yet another fake plant in the IJT versus import saga?

Has anyone actually spoken to people involved intimately or peripherally with the IJT program to confirm that this one single report is true?

It is important to get that right, or else we will be reaching conclusions and solutions for problems that have been misreported or even cooked up.

That is what I am getting at.


Shiv Saar, +1 for that. There is just too little information to assume on the nature of problem and fixes and the stated problem would have been noticed at a much earlier development phase (in my opinion) not after so many flight hours.

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Re: Indian Military Aviation- September 29 2013

Postby Pratyush » 07 Jun 2014 10:53

Can one ever make the hard landing on an arrested recovery go away.

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Re: Indian Military Aviation- September 29 2013

Postby symontk » 10 Jun 2014 13:23

I am noticing that few Mirage2000 are in Bangalore, saw one taking off almost vertically

Also saw an Indian AEWCS landing. May be it landed in HAL due to the presence of CABS

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Re: Indian Military Aviation- September 29 2013

Postby vic » 10 Jun 2014 22:36

Pratyush wrote:Can one ever make the hard landing on an arrested recovery go away.



It seems like word play to disguise a crash. One would need to see the pics to comment definitely.

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Re: Indian Military Aviation- September 29 2013

Postby srin » 11 Jun 2014 01:01

A carrier landing is a controlled crash. And pilots must accelerate as they touch down in the event that the tail hook doesn't catch the arresting cables.

I'm seriously puzzled about the fuss - isn't this normal ? I mean, there is a reason you have the third cable - in case the first two didn't snag the hook.

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Re: Indian Military Aviation- September 29 2013

Postby JayS » 11 Jun 2014 01:45

rrao wrote:why cant scaled down RC models of IJT,LCA and SARAS be made and flight performance to some extent be evaluated? The YAK130 with micro turbo engines resembles the original one!!! companies like TAAL, NAL and IITs and university students can make these RC planes...of course making them is not an easy one with available tech resources!!!


Making an RC model would be piece of cake for ADA/HAL. Thing is you can't achieve the actual flight Reynolds number with it. And phenomenon like Stall/spin are very sensitive to Re number and the conditions would be almost impossible to achieve. An RC model would probably fly with ease in situations where an actual full scale plane struggles. It might give a lot of other important flight data but I think that kind of data could be collected though WT testing as well. There are other factors like surface roughness, minute details like poking screw-heads on actual airplane which could affect flow in significant way but would be impossible to imitate by RC model. I am sure if it was so much more helpful, it would have been a widespread practice already. People have used this previously. It could be used as demonstrator but it still can't replace full scale flight testing.

Even state-of-the-art CFD can't help much in the flight regimes where large scale separation is involved. So far CFD is used only as sub-systems and analysis (and recently to some extent design) tool. Full config simulations are limited to only few regimes of flows.

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Re: Indian Military Aviation- September 29 2013

Postby JayS » 11 Jun 2014 02:06

Rahul M wrote:thanks vic. so if the news of asymmetric wing stall is correct, the likely cause is differential use of ailerons ?
the other reasons, (pax more on one side, ice formation etc are not that likely IMO)
I doubt the the wings themselves are so asymmetrically made that they lead to one stalling before the other.


Rahul, Its possible to have an asymmetric wing drop even when the wings are perfect mirror image of each other and the plane's attitude is perfectly symmetric. The turbulent airflow itself is chaotic in nature. You can have large flow separation started on one wing just a fraction of moment before the other due to very nature of turbulent flow.

Once an IIT prof told the story (he used to work in HAL earlier) how they encountered the issue of random wing drop on some aircraft (can't remember which) and they could find nothing wrong with the wings. Later on some experts from some lab (may be NAL) figured out that the very nature of flow makes its almost impossible to have perfectly symmetric flow as such and one wing or the other would drop depending on the situation for that particular plane. They figured out another way to make the stall smooth IIRC.

Now do we know if IJT issue is random wing drop?? I mean either of the two wings could drop and there is no preference?? Probably the it has steep and sudden stall characteristics which could explain the wing drop. In that case, they might be trying to make the stall smoother, as Indranil was theorizing few posts ago.

There is scarcely any technical info available regarding the actual issue. Pity our agencies don't publish much of their research in a way which is more accessible to average joe like NASA does.


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