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

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

Postby ramana » 21 Jun 2018 21:00

I think its the IAF chief who accepts the FOC.

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

Postby ArjunPandit » 21 Jun 2018 22:59

disha wrote:Disappointed that there is no lungi dance for Tejas making 4000 sorties!
I know several doubts still persist on this flight of Tejas ;-)

Was it LM that said that the plane can't fly and safety of test pilots etc etc

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

Postby prat.patel » 22 Jun 2018 01:57

Do we know how many flight hours in these 4000 sorties?

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

Postby ks_sachin » 22 Jun 2018 04:18

ramana wrote:I think its the IAF chief who accepts the FOC.


No dont think so. The IAF should have an equiv of the W&E Directorate. They probably....

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

Postby Khalsa » 22 Jun 2018 06:24

ramana wrote:I think its the IAF chief who accepts the FOC.

ks_sachin wrote:No dont think so. The IAF should have an equiv of the W&E Directorate. They probably....



Apologies I failed, let me try again.

Is the pen that signs off on the FOC called Squadron 45 (in July 2018) or can it be the Pen; Flying Bullets in September 2018.
because there was a snag in the AAR and FOC was moved to September 2018.

i.e. if there was snag in the AAR leading to the delay in FOC.
Can 45 be moved off to TN and Flying bullets continue the process of FOC.

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

Postby JayS » 22 Jun 2018 08:51

The IAF Sq are not involved in certification. They are doing their own work related to user exploitation trials for operationalizing LCA. National Test Flight Centre does the flying work.

The LCA commitee decides what should be the milestones for FOC. CEMILAC gives FOC.

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

Postby Arun.prabhu » 22 Jun 2018 09:29

*Deleted*

Mod Note: Go to missile thread/newbie thread/Aerospace tech for this discussion. Its not germane here anymore.

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

Postby tsarkar » 22 Jun 2018 14:06

ramana wrote:I think its the IAF chief who accepts the FOC.

ks_sachin wrote:The IAF should have an equiv of the W&E Directorate. They probably....

CEMILAC, an independent DRDO agency certifies all military aircraft IOC & FOC, whether Indian or foreign, whether during induction or after mid life upgrades.

https://www.drdo.gov.in/drdo/labs1/CEMI ... mepage.jsp

Check out how recent certification includes Boeing P-8I. This is for the benefit of member Krishna Krishna who thinks foreign products are not tested or certified in India.

https://www.drdo.gov.in/drdo/labs1/CEMI ... chieve.jsp

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

Postby sanjayc » 22 Jun 2018 14:12

prat.patel wrote:Do we know how many flight hours in these 4000 sorties?


Read this somewhere:
"Series Production (SP) aircraft SP-1 to SP-8 are not part of the LCA-Tejas flight test programme but are part of 1st LCA Squadron of the Indian Air Force and all sorties carried out by the LCA-Tejas Squadron are not included in the developmental and testing sorties."

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

Postby JayS » 22 Jun 2018 14:28

prat.patel wrote:Do we know how many flight hours in these 4000 sorties?


If you ask nicely I think LCA FB page admin might tell you the number. My guestimate is it should be somewhere in 2700-3000Hrs.

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

Postby Pratyush » 22 Jun 2018 14:33

Do we know what is the holdup for Tejas in-flight refueling test.
Last edited by Pratyush on 22 Jun 2018 14:52, edited 1 time in total.


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

Postby JayS » 22 Jun 2018 15:33

Pratyush wrote:Do we know what is the holdup for Tejas in-flight refueling test.


Where is hold up..?? It all looks like going as per plan to me. They are churning our almost 2 test flights per day. But if you only mean by wet contact and actual fuel transfer, they have to do a lot of tests and dry runs before than, which is what is happening until now. I think we will soon here some good news on this.

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

Postby Philip » 22 Jun 2018 16:20

Kaveri reportedly given the green light by SNECMA " for integration".Will we now have flying testbed platforms using a twin-engined bird or straight LAX prototypes flying with Kaveri?

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

Postby suryag » 22 Jun 2018 16:54

Wish Abhibhushan saar makes a visit to the cave before the warriors leave to Sulur.

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

Postby ramana » 22 Jun 2018 19:56

saar not sir.

saar is our own. sir is distant.

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

Postby suryag » 23 Jun 2018 08:29


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

Postby JayS » 23 Jun 2018 10:05

suryag wrote:lots of updates
IAF, HAL end impasse over Tejas trainers


Nice article. Lot of good indicarions. Heartening to see willingness to compromise for greater good from all parties.

Good to know theybare already doing AAR resting with Su30. There was a wake impact simulation snippet shown in Ai17 for LCA taking fuel from Su30.

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

Postby Pratyush » 23 Jun 2018 10:17

JayS wrote:Where is hold up..?? It all looks like going as per plan to me. They are churning our almost 2 test flights per day. But if you only mean by wet contact and actual fuel transfer, they have to do a lot of tests and dry runs before than, which is what is happening until now. I think we will soon here some good news on this.


I asked as we have already seen hot refueling of the Tejas on the ground. Inflight refueling is just doing it in the air.

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

Postby Indranil » 23 Jun 2018 10:42

They are not worried about the fuel transfer, but the ability to fly in the wake for long durations.

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

Postby ashishvikas » 23 Jun 2018 11:26

JayS wrote:
prat.patel wrote:Do we know how many flight hours in these 4000 sorties?


If you ask nicely I think LCA FB page admin might tell you the number. My guestimate is it should be somewhere in 2700-3000Hrs.


ADA insiders says as on June 20, 16 platforms from LCA flight-line logged 4,005 sorties clocking 2596.10 hours in the past 17 years and five months.

Read more at: https://english.manoramaonline.com/news ... e-end.html

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

Postby ramana » 23 Jun 2018 11:58

suryag wrote:lots of updates
IAF, HAL end impasse over Tejas trainers


Very good decision as it allows MK1 both configs to be completed without changing the line.
Role of ADA is interesting.

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

Postby JTull » 23 Jun 2018 12:03

Over 1000 sorties by the squadron SP aircraft and 4000 others. That's shows how safe and reliable it is.

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

Postby SriKumar » 23 Jun 2018 21:06

Indranil wrote:They are not worried about the fuel transfer, but the ability to fly in the wake for long durations.
One assumes flight control laws have to be modified and tested as well to account for changing center of gravity during in flight refueling (in the presence of a wake).

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

Postby Neshant » 24 Jun 2018 02:54

SriKumar wrote:
Indranil wrote:They are not worried about the fuel transfer, but the ability to fly in the wake for long durations.
One assumes flight control laws have to be modified and tested as well to account for changing center of gravity during in flight refueling (in the presence of a wake).


Automatically adapting to weight and center of gravity changes during flight should already be part of the flight control should it not?

Surely the fuel load changes all the time during flight as the aircraft burns fuel or has to dump it's fuel for an emergency landing. Ditto for following in the wake of any aircraft.

Maybe the wake of the refueling tanker + refueling has an unexpected effect.

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

Postby SriKumar » 24 Jun 2018 06:27

Neshant wrote: Automatically adapting to weight and center of gravity changes during flight should already be part of the flight control should it not?

Surely the fuel load changes all the time during flight as the aircraft burns fuel or has to dump it's fuel for an emergency landing. Ditto for following in the wake of any aircraft.
This 'automatic adapting' is exactly what the flight control system does. And unless the scenario is explicitly designed for, I would not think the FCS (developed for a related scenario) can be expected to handle this scenario, even if it is similar. My position is that it has to be written specifically for this function, and tested explicitly. About burning fuel and dumping, sure it is related to this task....but one clear difference, the C.G. changes in the opposite direction....the aircraft C.G. goes down when burning/dumping, and will go up in the case of refueling- and it is flying when this happens. This might be a new area of flight control that's not been tackled so far. There might be new attitudes the aircraft has to maintain while refueling e.g. thenose must be mostly horizontal and stable the aircraft nose has to be within a certain envelope even if the plane 'rocks a bit' in the wake. (I'm not saying it is difficult to program, just saying that this are (relatively) new situations and which need to be explicitly worked on). And yes, wake of tanker would be different from wake of a fighter aircraft (wake penetration tests were done 2-3 (?) years ago seen in the LCA video, I dont know if that was with a tanker/cargo type aircraft. I am assuming it was with other fighters for formation flying).

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

Postby Dileep » 24 Jun 2018 07:37

So.... you think that some smart gal is sitting there and figuring out how the CG changes and design the code? These things are modeled in fine detail and the models are validated over decades of flight testing. CG movement is the 'piece of cake' part here.

Think of stuff that can not be easily modeled, either because of the complexity of the phenomena (like wake of the tanker) and/or unavailability of accurate models (like that of the probe sticking out from the cheek), which may need to be made and validated.

THEN... what happens when the model 'flies into problems'? That is the real McCoy which causes delays, not the 'programming'. I had reported one such issue here.

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

Postby SriKumar » 24 Jun 2018 07:54

Well Dilip, my posts mentions most of what you mention.....wake, validation, programming AND testing explicitly. I dont know of what specific problem was reported here, feel free to mention it again. I could think of one other scenario e.g. refueling in 'less than perfect' turbulent weather (= weather + wake). Weather may not cooperate when refueling is urgently needed...so what happens then.

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

Postby Rahul M » 24 Jun 2018 09:05

I have a question regarding this, once the wake of the tanker is validated for tejas, is this specific to the tanker model i.e IL-76 or would work for any ? if there's a change involved for a different model, how time consuming would that be ?

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

Postby Pratyush » 24 Jun 2018 09:19

You ask one question and you get half page of replies. That gives you an insight into just how many variables that a designer has to keep track of before the design can approach it full potential.

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

Postby Khalsa » 25 Jun 2018 02:23

JayS wrote:The IAF Sq are not involved in certification. They are doing their own work related to user exploitation trials for operationalizing LCA. National Test Flight Centre does the flying work.

The LCA commitee decides what should be the milestones for FOC. CEMILAC gives FOC.



Thanks Jay, perfect answer and spot on.
It removed any doubts I had of what the Initial squadrons do in achieving FOC.

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

Postby Prasad » 25 Jun 2018 10:33

Rahul M wrote:I have a question regarding this, once the wake of the tanker is validated for tejas, is this specific to the tanker model i.e IL-76 or would work for any ? if there's a change involved for a different model, how time consuming would that be ?

IIrc there was some report of wake testing for both tanker and mkis. Each aircraft most likely has a different wake turbulence no?

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

Postby Indranil » 25 Jun 2018 23:04

Srikumar,

Ofcourse the CG travels as the aircraft fuels up, and you are right that the software has to be validated for that direction of CG movement, but there are two aspects here.
1. It has been tested on the iron bird first, and only then it would have been cleared for flight testing.
2. The change in the response of the aircraft to the CG-travel is still very slow compared to the turbulent air of the wake. In the later case, the aircraft will amplify the movement created by a gust by 32-times by the end of the second. Also, the wake cannot be simulated on the iron bird. I think is what Dileep sir was referring to.

Rahul da,
In theory, they should be tested. It is not just the type of aricraft, but things like degrees of sideslip etc. But after a few flights, one has developed enough confidence to say, all will be well.

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

Postby JayS » 25 Jun 2018 23:19

Rahul M wrote:I have a question regarding this, once the wake of the tanker is validated for tejas, is this specific to the tanker model i.e IL-76 or would work for any ? if there's a change involved for a different model, how time consuming would that be ?


I am 99% sure there must be separate certification for each tanker. Only thing after first one the subsequent ones must be much easiers to get and must be more like procedural types. If they can prove based on simulations for ex that the new type is within already certified tanker's limits, CEMILAC could accept it as good enough proof and with minimum flight tests the new tanker type can be certified.

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

Postby Rahul M » 25 Jun 2018 23:24

Prasad wrote:
Rahul M wrote:I have a question regarding this, once the wake of the tanker is validated for tejas, is this specific to the tanker model i.e IL-76 or would work for any ? if there's a change involved for a different model, how time consuming would that be ?

IIrc there was some report of wake testing for both tanker and mkis. Each aircraft most likely has a different wake turbulence no?

yup, that's why I asked. I was wondering if SW can handle that variation if a baseline has been proven and if that is considered enough.

Thanks for the answer, JayS.

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

Postby Bala Vignesh » 25 Jun 2018 23:51

Jays, so it means that each tanker and receiver pair must be individually certified for usage?? That would mean a lot of work for NATO forces since the refuellers and receivers are from different countries so how would they certify on all the refuellers in NATO??


Just wanted to clarify on this, sorry if OT.

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

Postby SaiK » 26 Jun 2018 00:19

Pl ignore if already posted

LCA Tejas Gears up for Aerial Refuelling
http://www.aeromag.in/aerospacesingle.php?aero=271

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

Postby JayS » 26 Jun 2018 00:27

Bala Vignesh wrote:Jays, so it means that each tanker and receiver pair must be individually certified for usage?? That would mean a lot of work for NATO forces since the refuellers and receivers are from different countries so how would they certify on all the refuellers in NATO??


Just wanted to clarify on this, sorry if OT.


As I said first one takes most efforts. Subsequent ones muat be much easier. Yes, there is a lot of hard work that goes in such flight testing. Nothing is left for chances, nothing is taken for granted. You have to demonstrate every thing. Only sometimes for some test points you can use simulations. For ex if Tejas is certified for IL78 and ADA can show CEMILAC to their satisfaction usong simulations that wake parameters for Su30MKI are within already demonstrated limits of IL78, CEMILAC may give certification for Su30MKI without having to go thru entire test set again. Only a few key flight tests could be enough.

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

Postby kit » 26 Jun 2018 00:53

Cool., the ADA, HAL all developing core expertise ..will do the country well.. every penny spent is worth a hundred times more

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

Postby kit » 26 Jun 2018 00:55

Rahul M wrote:I have a question regarding this, once the wake of the tanker is validated for tejas, is this specific to the tanker model i.e IL-76 or would work for any ? if there's a change involved for a different model, how time consuming would that be ?


I guess the learning curve will be smoother for other planes once this happens .. the HAL / ADA etc have never done anything like this before on their own ..


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