Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019

Dileep · Post by **Dileep** » 19 Jan 2020 21:18

I will have one more opportunity to talk to the guys soon enough. I will try to pry out answers.

Indranil · Post by **Indranil** » 19 Jan 2020 21:55

Excellent update.

I was thinking. May be HAL/ADA/IAF/MOD should sit down and consider an accelerated delivery for the Mk1As and squeeze in a production run of 110 Mk2s before the MWF. Just cancel this 110 imported business.

Much of the Mk2 detailed design is complete.
1. A little over half a meter of fuselage plug.
2. 414 engine
3. DSI intakes
4. Wingtip pylons
5. Larger and more efficient fuel tanks.
6. Aerodynamic refinements to the fuselage for lower drag.

All of the above except point 3 is complete. They can get this aircraft ready for production in 3 years. It will not require significant testing as it is basically an slightly larger LCA. If these 200 aircraft can be delivered in 10 years? What is the need for the imported single engine fighters? We will save a lot.

putnanja · Post by **putnanja** » 19 Jan 2020 22:21

Indranil wrote:Excellent update.

I was thinking. May be HAL/ADA/IAF/MOD should sit down and consider an accelerated delivery for the Mk1As and squeeze in a production run of 110 Mk2s before the MWF. Just cancel this 110 imported business.

Much of the Mk2 detailed design is complete.
1. A little over half a meter of fuselage plug.
2. 414 engine
3. DSI intakes
4. Wingtip pylons
5. Larger and more efficient fuel tanks.
6. Aerodynamic refinements to the fuselage for lower drag.

All of the above except point 3 is complete. They can get this aircraft ready for production in 3 years. It will not require significant testing as it is basically an slightly larger LCA. If these 200 aircraft can be delivered in 10 years? What is the need for the imported single engine fighters? We will save a lot.

I thought Mk2 length was 14.6m compared to 13.2m of Mk1. How is it possible with just half a meter fuselage plug?

Indranil · Post by **Indranil** » 20 Jan 2020 05:02

Putnanja sahab, you are speaking of the MWF. I am speaking of the original Mk2 studies. It was supposed to have a length of 13.7 meters.

You can read more about it here

fanne · Post by **fanne** » 20 Jan 2020 05:33

Dileep wrote:There was a 'conference' by SIATI on Fri Sat at HAL Convention Centre. Got some gyan from the presentations.
....
The TED BF picture is just that, "a picture that people didn't reject right away" during the brainstorming.

Shouldn't this be on the first page sticky before being buried in the forum pages?

Indranil · Post by **Indranil** » 20 Jan 2020 05:42

Yes. Rakesh, you are the karta-dharta of that. Please do the needful.

Dileep · Post by **Dileep** » 20 Jan 2020 06:54

One correction: "Jigs calibrated to 80 micron"

putnanja · Post by **putnanja** » 20 Jan 2020 07:08

Indranil wrote:Putnanja sahab, you are speaking of the MWF. I am speaking of the original Mk2 studies. It was supposed to have a length of 13.7 meters.

You can read more about it here

Yes, I remember the original Mk2. Since it sort of evolved into MWF, I guess I got a bit confused by your post where you were talking about inducting the original Mk2. Missed the part about Mk2 before MWF you had mentioned. my bad!

Rakesh · Post by **Rakesh** » 20 Jan 2020 07:18

Indranil wrote:Yes. Rakesh, you are the karta-dharta of that. Please do the needful.

Page 1 updated.

Aarvee · Post by **Aarvee** » 20 Jan 2020 07:23

Sorry, FOC by March "2021"? Thought it was imminent!

Rakesh · Post by **Rakesh** » 20 Jan 2020 07:24

Production of the 20 FOC aircraft are expected to be completed by March 2021.

Aarvee · Post by **Aarvee** » 20 Jan 2020 07:56

Aah, makes sense. Thanks for clarifying.

fanne · Post by **fanne** » 20 Jan 2020 08:46

8 micron would have been phenomenal, is 80 good? I googled up, it looks like the neighborhood guys in Massa makes 80 micron precision stuff. Is that much precision/margin good enough in aerodynamics? I guess end goal is full interchangeability, and if that goal is reached who cares if it is 80 or 8.

Another q, it looks like 60% of LRU is made in India, 40% imported (these are LRU only, not the whole plane)….somewhere over the web an allegation was made that by value, 70% of LCA is still imported (not that it matters, we own design and glad can source best part from anywhere), BUT, it would be good to have most of it home made. I can think of Engine, Radar, EW, AA missile? What else - actuators?

Dileep · Post by **Dileep** » 20 Jan 2020 09:43

The 80 micron is the precision of the whole jig, which is like several meters in length, and that too assembly of many sub parts. Imagine the bumper to bumper length of your car, and maintaining 80 micron. P-friggin-henomenal that is.

Thakur_B · Post by **Thakur_B** » 20 Jan 2020 10:29

Euro fighter documentary I saw a while back stated 60 microns for panels. In one of the factories built on a bog, lunar cycles would move the ground by millimeters, so the jigs they were using were hovercraft style floating on a layer of air.

Kartik · Post by **Kartik** » 20 Jan 2020 13:32

Kanson wrote:
Kartik wrote:
I don't believe that. Every program progresses through phases and the IOC is a phase where 60-70% of what is required in the eventual platform, is flight tested and certified. Some features and software continue to be developed while the airframe, FCS and other software is ready. Basically to help in the production line getting started off rather than waiting till everything is developed and certified.

Of course, the rich experience gained with the Tejas Mk1 means that a lot of capabilities that took more time to be developed and certified will take less time. The flight testing will not be as long drawn as fewer test points will be checked out, but nevertheless, every thing still needs to be tested and certified.
-
Below video makes it crystal clear. Thought i should post this video after reading recent idrw article on this.
1. Those 4 prototypes are of production stds and no TDs.
2. First flight is by 2021 end or 22 beginning.

Crystal clear since AI-2019 that production standard MWF prototypes will be built and no TDs. The baseline Tejas design has allowed that much progress to be made so the basic MWF technologies are already proven and exist on the Tejas program.

However, just because they'll be production standard prototypes doesn't mean they'll be at FOC level the moment they roll out. The program (like EVERY other program) will go through phases where the equipment, the FCS, other software, the airframe, etc, will all be thoroughly tested out and incrementally cleared to a higher level till it reaches IOC and then FOC. But production will begin with drawings released for manufacture whenever it reaches IOC itself.

JayS · Post by **JayS** » 20 Jan 2020 15:18

fanne wrote:8 micron would have been phenomenal, is 80 good? I googled up, it looks like the neighborhood guys in Massa makes 80 micron precision stuff. Is that much precision/margin good enough in aerodynamics? I guess end goal is full interchangeability, and if that goal is reached who cares if it is 80 or 8.

There is no single value by which one can judge accuracy. This is only about the jig, not the parts themselves. There are thousands of tolerances od dozens of types, some are in microns some in milimeters. Interfaces are always given more love to maintain good interchangeability.

JayS · Post by **JayS** » 20 Jan 2020 15:22

Kartik wrote:
Kanson wrote:
Below video makes it crystal clear. Thought i should post this video after reading recent idrw article on this.
1. Those 4 prototypes are of production stds and no TDs.
2. First flight is by 2021 end or 22 beginning.
Crystal clear since AI-2019 that production standard MWF prototypes will be built and no TDs. The baseline Tejas design has allowed that much progress to be made so the basic MWF technologies are already proven and exist on the Tejas program.

However, just because they'll be production standard prototypes doesn't mean they'll be at FOC level the moment they roll out. The program (like EVERY other program) will go through phases where the equipment, the FCS, other software, the airframe, etc, will all be thoroughly tested out and incrementally cleared to a higher level till it reaches IOC and then FOC. But production will begin with drawings released for manufacture whenever it reaches IOC itself.

You are right Kartik, the featureas and capabilities, though might exist in delivered SPs, will only be released for operational usage after the due certification process. Its all about configuration management. 30yrs of experience gives the team this confidence that they can pull this off. Of course there will be minor concurrent production changes, but the skill is to make sure all major changes have been incorporated a priory and nothing major would come up later. And if at all it does, then the changes handled in phased manner without halting the production.

srai · Post by **srai** » 20 Jan 2020 16:10

^^^
Smoother path to production from flight tests certification. Virtually no wait in between.

Need to wait and see how the IAF’s IOC/FOC production go ahead comes into play. Can HAL continue to build low rate numbers and scale up production facilities while flight certification is underway (even before formal IOC/FOC)?

Dileep · Post by **Dileep** » 20 Jan 2020 16:32

One of the things the HAL guy said during the presentation was that there was no "User Evaluation Trials" for Tejas, as if that is a great thing. Maybe it is... I am pretty sure that the babufolk raised objection that UET was not done before placing the order. They have a procedure written for imported maal, and there will be problem when you bring in indigenous developed maal. Now that the process is somewhat set, we should not anticipate much problem from that angle.

Still, 'moving goalpost' and 'brochuritis' will still be a problem.

JayS · Post by **JayS** » 20 Jan 2020 19:10

Dileep wrote:I will have one more opportunity to talk to the guys soon enough. I will try to pry out answers.

Add one more question - Once the suppliers are reached to 8/yr rate which was planned AFAIK, Is HAL planning to off load more sub-assy work that they themselves are doing currently, eventually reaching to a stage where HAL does not do any sub-assy and no component level mfg either (except for some of the composite parts may be)..? If HAL has such plan, what is the timeline they see for it.?

Rakesh · Post by **Rakesh** » 20 Jan 2020 19:17

Dileep wrote:One correction: "Jigs calibrated to 80 micron"

I made that correction in your original post and also reflected on page 1 of this thread.

ramana · Post by **ramana** » 21 Jan 2020 00:26

JayS wrote:
Dileep wrote:I will have one more opportunity to talk to the guys soon enough. I will try to pry out answers.
Add one more question - Once the suppliers are reached to 8/yr rate which was planned AFAIK, Is HAL planning to off load more sub-assy work that they themselves are doing currently, eventually reaching to a stage where HAL does not do any sub-assy and no component level mfg either (except for some of the composite parts may be)..? If HAL has such plan, what is the timeline they see for it.?

JayS, Don't mind lekin this is a production planning question internal to HAL.
And also the way you worded it looks like a Lok Sabha Starred Question by a Congress MP!

JayS · Post by **JayS** » 21 Jan 2020 00:42

I might as well try for RS entry then.

Well, there is no big business secret about it. In fact, HAL needs to publically state such strategies that they might have.

ramana · Post by **ramana** » 21 Jan 2020 02:34

When we get more clout InshaGanesha will push for you to be there.

srai · Post by **srai** » 21 Jan 2020 02:47

JayS wrote:
Dileep wrote:I will have one more opportunity to talk to the guys soon enough. I will try to pry out answers.
Add one more question - Once the suppliers are reached to 8/yr rate which was planned AFAIK, Is HAL planning to off load more sub-assy work that they themselves are doing currently, eventually reaching to a stage where HAL does not do any sub-assy and no component level mfg either (except for some of the composite parts may be)..? If HAL has such plan, what is the timeline they see for it.?

I think the answer is in Dileep’s original post. There are six sets of jigs currently. Plan is to increase them to 16 sets. Any new sets will likely be with the out sourced suppliers for them to build up their capacities. Most probably HAL will keep its existing 5 sets; 83 units order is pretty small for the production run of 5-years. Larger orders and longer production run it would then have made better sense to outsource completely. As per HAL chairman, eventual goal is to outsource all and HAL to become a vertical integrator. We will likely see it during MWF production and subsequently all future programs.

Dileep wrote: 15. Capacity is 16 Aircraft/Year ---> Eight at LCA Division, four at Aircraft Division and four at our sourced suppliers (Alpha Tocol Engineering Services Pvt Ltd, TATA Advanced Materials Ltd, Larsen & Toubro and VEM Technologies Private Limited).

16. Six sets of jigs ---> four jigs at Tejas Division, one jig at Aircraft Division and one jig at sub-contractor site (front jig at Dynamatic Technologies Limited, rear jig at Alpha Tocol and mid jig at VEM Technologies Private Limited).

17. They reduced cycle times by adding sub-sub assembly jigs.

18. 43 types of jigs are required.

19. Jigs calibrated to 80 micron using a laser measurement system. That is quite fast. Full interchangeability achieved.

20. Present cycle time: 6 months per set. He outlined the plans to increase and reach the target of 16 sets.

Dileep · Post by **Dileep** » 21 Jan 2020 06:17

JayS wrote:
Dileep wrote:I will have one more opportunity to talk to the guys soon enough. I will try to pry out answers.
Add one more question - Once the suppliers are reached to 8/yr rate which was planned AFAIK, Is HAL planning to off load more sub-assy work that they themselves are doing currently, eventually reaching to a stage where HAL does not do any sub-assy and no component level mfg either (except for some of the composite parts may be)..? If HAL has such plan, what is the timeline they see for it.?

That is exactly the plan. The guy said that explicitly. No timeline was given, then such things can't have a timeline in our desh na?

Dileep · Post by **Dileep** » 21 Jan 2020 06:19

ramana wrote:When we get more clout InshaGanesha will push for you to be there.

Hey!! Maybe I should hire JayS and make him my customer facing guy in Bengaluru!! Deal?

I am actually looking for someone. Lousy company. Shitty pay, but you get the pass to take the HAL guys out for drinks on company expense sometimes.

Kartik · Post by **Kartik** » 21 Jan 2020 06:37

Dileep wrote:There was a 'conference' by SIATI on Fri Sat at HAL Convention Centre. Got some gyan from the presentations.

1. HAL really upbeat about completing the production of FOC Mk1 by March 2021.

2. Two of the IOC Mk1s are about to be handed over to IAF in 'these days'. Four FOC to be handed over before FY closes.

3. They are going full steam ahead with Mk1A. Order signing is only a formality.

So basically handing over 6 Tejas Mk1s in the next 2 months?

Did he mention anything about radar selection for Mk1A? and EW pod?

5. No 45 Daggers Sqn flew 2,500 operational hours and 3 aircraft completed the 250 hour servicing.

6. 311 "modifications" done concurrently in production.

7. 82 LRU suppliers for 344 types out of which 210 are indigenous.

8. High failure rate of 34 types LRUs which is still being worked on.

That's a pretty good operational tempo! With 2 of the Tejas Mk1 IOC jets still at HAL, No.45 would've only had 14 single seaters in hand. And even those were progressively delivered, so clearly some of the earlier SPs are getting flogged.

Did they mention anything about the squadron's impressions of the jet? How satisfied they are with the type? Hopefully those 34 LRUs with higher failure rates will be addressed soon enough.

15. Capacity is 16 Aircraft/Year ---> Eight at LCA Division, four at Aircraft Division and four at our sourced suppliers (Alpha Tocol Engineering Services Pvt Ltd, TATA Advanced Materials Ltd, Larsen & Toubro and VEM Technologies Private Limited).

16. Six sets of jigs ---> four jigs at Tejas Division, one jig at Aircraft Division and one jig at sub-contractor site (front jig at Dynamatic Technologies Limited, rear jig at Alpha Tocol and mid jig at VEM Technologies Private Limited).

20. Present cycle time: 6 months per set. He outlined the plans to increase and reach the target of 16 sets.

HAL hasn't yet reached 16 aircraft/year has it? Does 1 jig equate to 1 jet/year- or is it 1 jig equates to 2 jets/year @ 6 months cycle time each? Can't be if HAL can deliver 8 per year even as of now.

Did they give a timeline for when they'll reach that 16 aircraft/year number? Even today, ACM RKS Bhadauria pointed out that HAL needs to deliver now.

The TED BF picture is just that, "a picture that people didn't reject right away" during the brainstorming.

Ah, so as expected, the ORCA/TEDBF is at very preliminary stage?

Dileep · Post by **Dileep** » 21 Jan 2020 07:04

It was a "Supply Chain Conference" so, no juicy technical info was presented like radar EW etc.

The math doesn't add up clearly for 16 aircraft. We know that there are 6 jigs. So,theoretically if they can reduce the 6 months to 4.5 months, you can reach 16. But IMHO that is a tall order. Building more jigs is out of question, given the major capex involved.

So, realistically, we can expect 12 to 14 aircraft coming out in next FY.

Squadrons impression? Imagine you had been driving a battered Premier Padmini, and you are given a Tata Tigor Automatic. Would you be happy or not? Of course they are!! Like a kid who got a brand new bike for diwali!!

ramana · Post by **ramana** » 21 Jan 2020 07:41

Those 34 LRUS, what kind of issues?
I am expecting bad solder, mechanical work type problems.
Those are the typical problems.

Dileep · Post by **Dileep** » 21 Jan 2020 09:18

No idea what type of failures. Will ask. But being seen the way the suppliers build them, I agree with you.

Cybaru · Post by **Cybaru** » 21 Jan 2020 11:05

It is possible they meant F404-GE-IN20 or there is further evolution and improvements to the IN20 engine requiring a designation change.

ashishvikas · Post by **ashishvikas** » 21 Jan 2020 11:57

Indian Air Force’s LCA to get Astra missile firepower, not Rafale’s Meteor
https://economictimes.indiatimes.com/ht ... aign=cppst

srai · Post by **srai** » 21 Jan 2020 12:59

Dileep wrote:It was a "Supply Chain Conference" so, no juicy technical info was presented like radar EW etc.

The math doesn't add up clearly for 16 aircraft. We know that there are 6 jigs. So,theoretically if they can reduce the 6 months to 4.5 months, you can reach 16. But IMHO that is a tall order. Building more jigs is out of question, given the major capex involved.

So, realistically, we can expect 12 to 14 aircraft coming out in next FY.
...

6 sets of jigs
Each jig set has 43 sub/sub-sub assembly jigs

Total of 258 sub/sub-sub assembly jigs

Looks like you can get a lot of concurrent sub-sub assemblies going on.

Limit would be how many final assembly jigs are available to put all the major components coming out of the sub-jigs together. How many final assembly integration jigs total? Is it 6? If it is a 6, then as you have pointed out around 4 months in the final assembly integration jig to reach targeted output of 16/year.

Dileep · Post by **Dileep** » 21 Jan 2020 13:41

As per my understanding, the production goes as follows:

1. The front, mid and rear jigs are used to create the three major subassemblies. There are six sets of such jigs.
2. They are joined together with the wings and landing gear on the designated bay on the hangar floor. There is no jig for that. I am not sure how many such bays are there in the hangar. But that is not a problem I think.
3. 'Equipping' happens then. People go into the structure and assemble the LRUs, cables, pipes, actuators etc. There are a set of raised platforms to give access to the entire aircraft.

Kartik · Post by **Kartik** » 21 Jan 2020 13:48

Dileep wrote:It was a "Supply Chain Conference" so, no juicy technical info was presented like radar EW etc.

The math doesn't add up clearly for 16 aircraft. We know that there are 6 jigs. So,theoretically if they can reduce the 6 months to 4.5 months, you can reach 16. But IMHO that is a tall order. Building more jigs is out of question, given the major capex involved.

So, realistically, we can expect 12 to 14 aircraft coming out in next FY.

Squadrons impression? Imagine you had been driving a battered Premier Padmini, and you are given a Tata Tigor Automatic. Would you be happy or not? Of course they are!! Like a kid who got a brand new bike for diwali!!

Thanks Dileep. much appreciated!

JayS · Post by **JayS** » 21 Jan 2020 14:38

Dileep wrote:As per my understanding, the production goes as follows:

1. The front, mid and rear jigs are used to create the three major subassemblies. There are six sets of such jigs.
2. They are joined together with the wings and landing gear on the designated bay on the hangar floor. There is no jig for that. I am not sure how many such bays are there in the hangar. But that is not a problem I think.
3. 'Equipping' happens then. People go into the structure and assemble the LRUs, cables, pipes, actuators etc. There are a set of raised platforms to give access to the entire aircraft.

Thats my understanding too. For fuselage assembly they must have some basic jig to hold the the sub assy in correct position while its riveted together. Wings typically dont need jigs for attachement with fuselage. We do not have rolling line where each station has fixed work package.

The next step is where the equipping happens at the sub-assy level at the supplier location itself. So the finaly equipping step time reduces drastically. It also makes the MRO neater as one could simply replace entire module to reduce downtime for operational jets. I think this is already under consideration for MWF. When we are there we would have caught up with the current global practice more or less. I am very sanguine about the MWF from the production technology perspective. Its a very much needed step before moving to AMCA which is going to need further enhanced accuracy in manufacturing processes and tolerances to maintain its stealth.

kit · Post by **kit** » 21 Jan 2020 16:39

Thakur_B wrote:Euro fighter documentary I saw a while back stated 60 microns for panels. In one of the factories built on a bog, lunar cycles would move the ground by millimeters, so the jigs they were using were hovercraft style floating on a layer of air.

while on the subject of tolerances.,

Building the F-22
https://www.flightglobal.com/building-t ... ?adredir=1

Simpson says that a good weld requires "very exacting machining tolerances at the joints." The thickness of the structure, which must carry the engine, as well as tail, loads, adds to the difficulty of the task. Results so far have been excellent, he says, with the welding process proving to be "very repeatable". In production F-22s, the complete booms will be welded, eliminating the present mechanical joints.

Dimensional control is critical on the F-22 - and not just to maintain tight tolerances on the external lines to minimise radar cross-section. "We have cut the margin for fit-up to the lowest possible level. We cannot afford any slop in the joints, as this affects fatigue life," Simpson says. "We are looking for a perfect fit, with minimum shimming. A better fit means less stress, less wear and tear, for a higher fatigue life and lower weight," he adds.

Traditional fabricated-aluminum bulkheads, frames and racks have been eliminated and replaced by single-piece machined components. Five-axis machining of bulkheads results in major weight savings in the mid- and forward fuselage, while holding tolerances three times tighter than those achieved in the Lockheed Martin F-16.

SidSoma · Post by **SidSoma** » 21 Jan 2020 20:21

Traditional fabricated-aluminum bulkheads, frames and racks have been eliminated and replaced by single-piece machined components. Five-axis machining of bulkheads results in major weight savings in the mid- and forward fuselage, while holding tolerances three times tighter than those achieved in the Lockheed Martin F-16.

Well absolute tolerance levels are muddling. Flatness tolerances of 0.025mm for aluminium/steel plates are achievable even with a modest grinding machine for lengths upto one meter by one meter (Personally have seen something like this) So I am not sure why single piece machining is highlighted for these tolerances, may be because of the larger lengths. Almost Any thing that can be done quickly in 5 axis machine can be done slowly in a 3 axis one with the same kind of tolerances. I have seen aero engine parts with much tighter tolerances (<0.010mm) these are regularly made in India for various orgs