LCA Tejas: News and Discussions

Hobbes · Post by **Hobbes** » 18 Jun 2015 05:43

Karan M wrote:
Singha wrote:looks like uttam has a long way to go if 1.5 is going to use EL2052 radar.
the israelis will smell a good opportunity to supply EL2052 for Mk2 also once they have the foot in door and try to overwhelm the 1.0 Uttam with features since they have a 10 year head start + access to US parts cots

I think we should also look to upscale the Uttam for fitment on the SU30 fleet. russian aesa promises much but might not be able to deliver, and its always better to control radars and EW both for quick changes and security pov. Su30 has a huge nose and carts the 750kg bars, so there is not much space constraints there.
IAF has indeed asked LRDE to consider Su-30 for Uttam as well.

Excellent. Has the Uttam progressed to implementation and testing of the A2G mode yet, or are they still working on refining the A2A mode?

srai · Post by **srai** » 18 Jun 2015 12:42

deejay wrote:First 20 Tejas in IOC 2 config only. Once those come out only then do we need FOC aircraft. Till we produce the first 20, there is time for FOC to happen. As of now SP2 is to be delivered and then 18 more. I don't think the first 20 will come before 2017 end. After that at least two more years for the next 20 in FOC config.

Recent news is that the IAF will get 36 in FOC format. IOC-2 will be limited to 4 units.

Aero India 2015: ADA Chief says IAF will get 36 Tejas in FOC format

deejay · Post by **deejay** » 18 Jun 2015 16:32

srai wrote:
Recent news is that the IAF will get 36 in FOC format. IOC-2 will be limited to 4 units.

Aero India 2015: ADA Chief says IAF will get 36 Tejas in FOC format

srai ji, IAF's requirement remains as contracted. The ADA is confident that it can deliver FOC level aircraft from SP 4 onwards. It is not contractual. I would desist from such positions as now there is an additional pressure to deliver from SP 4 onwards when we are still waiting for COBHAM to complete our assurance. Why make such promises?

From the linked article:

As per the contract, HAL will have to deliver a total of 20 Tejas series production aircraft in the Initial Operational Clearance (IOC) format and another 20 in the FOC mode.

and

Subramaniam claimed that they are confident of handing over the FOC versions of Tejas from SP-4 onwards. "We are sure that from SP-4 onwards (likely to be rolled out by HAL during the end of 2015), IAF will start getting the Tejas that matches all FOC requirements. Hence, the IAF will be ready with 36 FOC Tejas aircraft, instead of 20 as per the order," Subramaniam said.

What was heartening to note in the article when it came out was this:

Squadron formation activities gather momentum in Sulur
He said the IAF technicians have already started their training sessions with HAL. An ASMS (Aircraft System Maintenance Simulator) is also operational to train technicians on the maintenance of various systems on Tejas. He confirmed that the civil works have already begun at Air Force Station Sulur, which will be the base for the Tejas. "We are on an advisory mode now. The designers have already started interacting with the IAF team in Sulur on matters related to facilities," he said. A Full Mission Simulator is expected to reach Sulur soon. He said the IAF pilots will start flying the Tejas officially from April onwards.

Now April has come and gone and we are missing deadlines. IAF or HAL or ADA have not confirmed (AFAIK) that IAF has started flying. Why take on the load of FOC level from SP 4 onwards and again miss deadlines. Serves no purpose in my opinion. I would rather see the contractual 20 + 20 get completed.

ramana · Post by **ramana** » 18 Jun 2015 18:28

deejay, ADA and most civilian organizations overfeed on hope and services die of starvation.
After the long track record its irresponsible for ADA chief to make such unrealizable statements.

IFR and radome are not delivered yet.
Derby firing not done yet.
Gun firing trials are not there yet.
LRUs not re-qualified for gun firing loads yet.

I heard of Bangalore Biryani from chetak, but this is gorging on khyali pullao.

Its mostly driven by urge to pretend to be top performer when track record is below average/mediocre.

deejay · Post by **deejay** » 18 Jun 2015 19:18

ramana wrote:deejay, ADA and most civilian organizations overfeed on hope and services die of starvation.
After the long track record its irresponsible for ADA chief to make such unrealizable statements.

IFR and radome are not delivered yet.
Derby firing not done yet.
Gun firing trials are not there yet.
LRUs not re-qualified for gun firing loads yet.

I heard of Bangalore Biryani from chetak, but this is gorging on khyali pullao.

Its mostly driven by urge to pretend to be top performer when track record is below average/mediocre.

Ramana sir, both the IAF and DRDO labs should be voicing from a single platform in one voice. Even here IAF and ADA are on different pages. LCA programme will benefit a lot if public communication comes from only one source (and so would other programmes).

LRU re-qualification may have happened Ramana sir as the video of on ground firing exists and that would have provided the opportunity to stress test the LRU's already fitted. (I am guessing here).

ramana · Post by **ramana** » 18 Jun 2015 19:23

LRUs requal takes a lot of time as they have to be put on shaker table with the new response spectra and the results analyzed. And even after that they have to fly the plane and do gun firing trials with instruments( acceleration, vibration sensors) to confirm.

I agree the ground firing trials might have alerted them that they need to revisit the LRU qualifications.

One message now that its close to the finish line would be helpful.
But whom: ADA or IAF? I think before FOC, ADA and after IAF.
And would help if they don't talk to DDM.

Karan M · Post by **Karan M** » 18 Jun 2015 21:34

The problem with having only missile guys in Hyderabad as our heads was that these bigger programs didn't get the proper focus they deserved. Hope Christopher saar really sets the LCA right. Its on the cusp of induction and these last minute niggles get bad press, optics and also keep the IAF on tenterhooks. His bigger task and here is where having Parrikar should help, is to make HAL give the LCA due importance.

SaiK · Post by **SaiK** » 18 Jun 2015 23:55

+1.. it should not take 30 years to realize about how to set program priorities. this is not just about irresponsibility by gov, institutions and the whole r&d group, but each dept. including arm chair generals who failed to impress to take actions, has its share of failures (not system but project/deliverable/schedule/needs/engineering...).

At the very least, I want to hear: a real quick commission report (perhaps a joint IIM/IIT project study) on various projects and begin correction mode.

ramana · Post by **ramana** » 19 Jun 2015 00:18

Its called passive oversight. Fault in many organizations....

Karan M · Post by **Karan M** » 19 Jun 2015 01:34

Ramana sir in our case, the problem is fundamentally the lack of services involvement in these programs. Its not finger pointing at the IAF but just stating how that simple thing causes so many issues upstream and downstream. Program managers at ADA either don't get the importance of basic things, or are afraid to flag it if it shows up late (afraid of IAF comment) and end up flagging it even later (which worsens things even more). Lack of IAF involvement means critical decisions are not taken earlier, eg to go for GE404 from beginning as versus waiting for Godot (i.e. Kaveri) and deciding that MMR was unworkable and quickly moving to the alternate option. Alternate plans are subject to CAG criticism so program managers keep flogging Plan A till that horse is not only dead, but even the flies come back and request "enough". They have zero control over entities like HAL and hence wait for MOD clearance (which under folks like Antony would never come). In short, a LCA style program needs service involvement at every level (so clearances can flow quickly without finger pointing if local development, a highly ambitious program if there ever was one doesn't work out eg Kaveri or MMR) and HAL etc can be pressurized to treat LCA as first priority. Most importantly, the IAF gets upto date reviews, can know the exact status of what is what, and trust improves. In turn, the Air Marshals have to be firmly told their participation in such program is not merely sign off or use it as an excuse for imports or scupper the program, but that its success is their first priority and it cannot be allowed to fail. Folks like Shri strategic advisor to HAL come back after visiting furren lands and then state "hey, the AF has control over programs elsewhere, they can even cancel them if they want to, we should get the same". Who in their right mind from the technology side of things would trust these guys to take the right decisions then? In short, services have to be involved and at the same time, they have to accept the program cannot fail. They are in it, come what may. Only then will things improve as versus the current system.

PS: MMR not being funded adequately at HAL.
http://www.globes.co.il/en/article-1000723182
Thats $150 Mn for our Jaguars. Did any beancounter or babu sit down in Delhi and see this and issue any edict asking for adequate funding for future programs. Of course not.

shiv · Post by **shiv** » 19 Jun 2015 06:05

ramana wrote:LRUs requal takes a lot of time as they have to be put on shaker table with the new response spectra and the results analyzed. And even after that they have to fly the plane and do gun firing trials with instruments( acceleration, vibration sensors) to confirm.

I agree the ground firing trials might have alerted them that they need to revisit the LRU qualifications.

One message now that its close to the finish line would be helpful.
But whom: ADA or IAF? I think before FOC, ADA and after IAF.
And would help if they don't talk to DDM.

ramana it strikes me that LRUs are exactly that LRUs - i.e line replaceable units. Admittedly they must be requalified but surely the purpose of any LRU is easy and quick replacement. Remove the one that requires requalification replace with another and keep going. Yes it raises cost - but for testing everything raises cost, time, breakdowns, accidents etc

Of course if the issue is structural integrity inspections after gun firing then it's a different issue.But the article did say "LRU requalification" and not structural integrity - so the latter may be a bogey that I have pulled out my musharraf

Singha · Post by **Singha** » 19 Jun 2015 06:50

I think printed circuit boards have multiple embedded layers of tiny wires, with the chips soldered on top layer. heavy vibration or bending might break some connections by delamination of layers or shaking some soldered pin loose....

Neilz · Post by **Neilz** » 19 Jun 2015 08:32

PCB(printed circuit boards) are made of multiple layers.. can 40+. It is very difficult to identify a line breakage and stress reason for that. PCB board in modern era designed with thermal and stress analysis + environment life cycle testing etc.. But then there is nothing which can simulate or predict a closed shell environment. and it is really really a time and money consuming iterative process.

edit: not only breakage due to vibration, even signal integrity of the PCB(internal) may show failure or deterioration.

Singha · Post by **Singha** » 19 Jun 2015 08:57

i was in a project where they spent around 1 yr using the most expensive tools and OEM support to chase signal integrity failures on a new backplane bus of a chassis. so these things can get nasty real fast.

srin · Post by **srin** » 19 Jun 2015 10:31

Karan M wrote:Ramana sir in our case, the problem is fundamentally the lack of services involvement in these programs. Its not finger pointing at the IAF but just stating how that simple thing causes so many issues upstream and downstream. Program managers at ADA either don't get the importance of basic things, or are afraid to flag it if it shows up late (afraid of IAF comment) and end up flagging it even later (which worsens things even more). Lack of IAF involvement means critical decisions are not taken earlier, eg to go for GE404 from beginning as versus waiting for Godot (i.e. Kaveri) and deciding that MMR was unworkable and quickly moving to the alternate option. Alternate plans are subject to CAG criticism so program managers keep flogging Plan A till that horse is not only dead, but even the flies come back and request "enough". They have zero control over entities like HAL and hence wait for MOD clearance (which under folks like Antony would never come). In short, a LCA style program needs service involvement at every level (so clearances can flow quickly without finger pointing if local development, a highly ambitious program if there ever was one doesn't work out eg Kaveri or MMR) and HAL etc can be pressurized to treat LCA as first priority. Most importantly, the IAF gets upto date reviews, can know the exact status of what is what, and trust improves. In turn, the Air Marshals have to be firmly told their participation in such program is not merely sign off or use it as an excuse for imports or scupper the program, but that its success is their first priority and it cannot be allowed to fail. Folks like Shri strategic advisor to HAL come back after visiting furren lands and then state "hey, the AF has control over programs elsewhere, they can even cancel them if they want to, we should get the same". Who in their right mind from the technology side of things would trust these guys to take the right decisions then? In short, services have to be involved and at the same time, they have to accept the program cannot fail. They are in it, come what may. Only then will things improve as versus the current system.

PS: MMR not being funded adequately at HAL.
http://www.globes.co.il/en/article-1000723182
Thats $150 Mn for our Jaguars. Did any beancounter or babu sit down in Delhi and see this and issue any edict asking for adequate funding for future programs. Of course not.

KaranM, there are actually multiple distinct but somewhat linked problems:
a) ADA chief giving unrealistic timelines.
b) IAF involvement
c) Delays

The fundamental principle of project management: "good, cheap, fast - pick any two". We want good (much better than the import maal) and we want cheap (R&D budget is negligible yet we want our own Kaveri) and delays are inevitable.

Delays have happened for other projects too. ISRO has delays (GSLV, Astrosat, our own cryo engine), IN has delays in almost every programme (IAC, scorpene, Kolkatas) - and this with ex-admirals being head of shipyards. Absence of criticism doesn't mean delays aren't there.

That and only then, we come to the main point - IAF non-participation in LCA. My feeling is that LCA would still be delayed, but not as much (change requests would come earlier and compromises worked out), but definitely the criticism would be muted. Because everybody would share the blame.

The setting of unrealistic timelines is a bit weird. It seems to affect everyone - including IAF (check what IAF chiefs kept saying about MMRCA being almost finalized), ISRO - and not just the HAL and DRDO.

ramana · Post by **ramana** » 19 Jun 2015 19:48

shiv, LRUs are qualified as packages and not board level qual. So they take the unit on shaker table and subject it to shock and vibration profile. Aircraft design standards are such qual levels are 1:500. A unit after that does not get deployed. Normal production/mfg errors(soldering, board flexing..) are accounted for by screening at 1:100 levels. Called Package Acceptance level. All this is called margin.
Aerospace relies on margin to account for unk/unks.

Most likely the initial package qual levels are low and o not envelope as built trials. Hence this round. Better to realize before flight than accident investigation.

One cannot analyze your way out with confidence.

Most avionics packages look short and compact L/D (form factor) is close 1-2 for a reason.

Will let vina elaborate

NRao · Post by **NRao** » 20 Jun 2015 00:14

Bright Future For GE’s F414 Fighter Engine

The engine was also selected by India for the LCA Mk.2. The first flight test engine will ship in the fourth quarter of this year, with production to begin in 2018.

Korea, Turkey and India are also prospects for the engine for their next-generation fighter programs, she says.

Meanwhile, the U.S. Navy is being pitched an F414 upgrade that would bring 20% more thrust, twice the power takeoff for systems, and lower maintenance costs. “It’s a very low-risk upgrade incorporating an all-blisk compressor and 3D aero in the compressor and turbine,” she notes.

The upgrade is also being considered by India for its next-gen fighter program, and a deal there could include partnering with Indian industry on design of components.

Karan M · Post by **Karan M** » 20 Jun 2015 04:49

I don't know why there is so much talk of LRU this, LRU that. Kartik's post from AI clearly states that the ground gun trials were for LRU verification and they went ok.

I don't see any recent report stating that its LRU verification holding up LCA FOC. Only mention/s are of radomes and IFR.

Karan M · Post by **Karan M** » 20 Jun 2015 05:04

http://forums.bharat-rakshak.com/viewto ... 3#p1803673

Kartik:

-I’ve uploaded the LCA Mk1 ground based gun firing trials video onto youtube..just search for “Tejas LCA gun firing trial”. It’s a short 5 sec clip. The gun trials were conducted to validate the vibration characteristics and to check whether structures, internal avionics and electronics can withstand it. No issues were seen during the trials.

Hobbes · Post by **Hobbes** » 20 Jun 2015 08:37

Latest update on LCA from Saurav Jha:

* The four things Holding up Tejas Mk-1 FOC are : Derby trials. Python trials. IFR and the new radome.

Looks like the gun firing tests are over. I thought the Python was a potential replacement for the R-73, which has already been tested on the Tejas. Do they want to replace the R-73 with the Python?

Pratyush · Post by **Pratyush** » 20 Jun 2015 10:51

I fail to understand the last 2 points. Why cant these things be executed during the depot level maintenance.

Austin · Post by **Austin** » 20 Jun 2015 10:58

Hobbes wrote:Latest update on LCA from Saurav Jha:

* The four things Holding up Tejas Mk-1 FOC are : Derby trials. Python trials. IFR and the new radome.

Looks like the gun firing tests are over. I thought the Python was a potential replacement for the R-73, which has already been tested on the Tejas. Do they want to replace the R-73 with the Python?

More likely IAF wants both or want to integrate what ever WVR missile in its arsenal possible , eg M2K is qualified for Python-4/R-73/R-550 ( post upg even Mica ), same goes for SU which will have Astra/R-77

Kartik · Post by **Kartik** » 20 Jun 2015 11:03

Because they need to be standard equipment for the FOC Tejas Mk1. Or even if not standard equipment, at least they need to test their solutions meet the IAF's requirement.

Cobham has disappointed with this major delay in delivering the probe and radome. But one good news is that Rafael's I-Derby ER missile will be the BVR missile integrated with the Mk1, with a max range of 100 kms..that will necessitate several trials with the new radome in place.

geeth · Post by **geeth** » 20 Jun 2015 11:06

It will be very difficult and expensive to make every chip/ circuit board etc to withstand enormous amount of shock & vibration. Instead, what is usually done is:

1. Fix the equipment / machinery (say gun) on a properly designed shock&vibration proof mounting. This will mitigate the transmission of such disturbances to the airframe.
2. Mount every LRU also on appropriate mountings. This will further mitigate the transmission of disturbances to the LRU.
3. Inside the LRU also, critical components can be mounted on proper mountings (sometimes using rubber washers would do the job). This reduces trasmission to individual component.

Not only aircrafts, even in ships and shore establishments, this is a common practice followed. Vibration mountings are so advanced, nowadays it plays a very important role in reducing the underwater signatures of warships to a large extent. Special mountings are always custom designed according to vibration charactiristics.

chaanakya · Post by **chaanakya** » 20 Jun 2015 11:07

Just becasue LCA is Indian make, It will have to go through all trials and tribulations and still will not be given FOC by "INDIAN" Air Force as it would not measure up to the best of Brochuritis specifications of all the best fighter planes in the world that would be made available by 2035.
Therefore we would not be surprised to hear of FOC-Initial and FOC-Pre Final and FOC-Just abt Final etc.

What are the issues plaguing LCA

Engines under powered
Areodynamics not yet streamlined.
AOA not goo enough.
Too heavy
Not Big Enough
Inadequate range
No Radar Integration
Canon not integrated
Ejection Seats not yet tested
Missile tests not yet done
AESA not provided
Kaveri not suited
Flight Director and Control System not fully tested
IFR not provided to extend the range
Radome not integrated
Not used by any Airforce
Production capacity not adequate
Not enough experience by our Pilots in flying LCA
No Trainer version available
We can't fight any war against enemy with what they have to throw at us. They are Soup-e-rear.
Well Pilots are always Precious and equipments are costly and we can't risk either of them in a "WAR" with LCA.

Do check what has been accomplished and what is left out and can be done and can't be done. Being DESI LCA will never be acceptable to Foreign FANBOYS Airforce.

chaanakya · Post by **chaanakya** » 20 Jun 2015 11:22

I propose that GOI order 240 LCA to HAL and direct it to set up production lines with adequate capacity to produce 36 a year, at least.
Each 18 LCA will be a modified Block version , better one from its earlier tranche. Set up Supply chain eco system to feed these production lines.
As and when requirements (ASR) is met the same may be incorporated in existing production lines. Funds may be made available from Defence Procurement budget and it would be released in yearly tranche as per delivery with first 36 released up front for setting up production lines.
Managment of HAL and ADA should be stremlined and strict timelines should be enforced on pain of action under Defence of India Act to bypass unionism of HAL. Let IAF Chief and Vice Chief sit on the Boards of ADA and HAL. IAF should set up Quality Inspectorate foe acceptance of each plane before delivery.

Let LCA be improved upon in Blocks or Tranche , eacch being productionised as being constantly improved upon. Feedback system from actual use Squadrons( not merely test Pilots) to ADA and HAL should be evolved in structured manner.

Vayutuvan · Post by **Vayutuvan** » 20 Jun 2015 13:41

Neilz wrote:PCB(printed circuit boards) are made of multiple layers.. can 40+. It is very difficult to identify a line breakage and stress reason for that.

Not necessarily. 40+ layers with ~10K discrete devices is about 400K devices plus the interconnect (between two nodes only one capacitance and one resistance for first approximation which is good enough for even VLSI/extreme Deep Submicron ASICS) will result in a circuit of a (nodal) size of O(400k) with a small constant hidden in the big-O. In gheneral, not a big problem to tackle on a well-endowed desktop today.

Karan M · Post by **Karan M** » 20 Jun 2015 13:50

Hobbes wrote:Latest update on LCA from Saurav Jha:

* The four things Holding up Tejas Mk-1 FOC are : Derby trials. Python trials. IFR and the new radome.

Looks like the gun firing tests are over. I thought the Python was a potential replacement for the R-73, which has already been tested on the Tejas. Do they want to replace the R-73 with the Python?

Thanks Hobbes.

There you go. Much discussion wasted on how ADA was not able to do gun trials whatever.

The sticking issue is the radome. Without it radar, cant get the range possible for optimal Derby employment. The radar is also linked to WVR missile launch (there is a WVR mode used). So radar has to be shown to work and then missile tests follow. IFR ditto.

Interesting the Israelis have radars but not radomes.

If this is what is remaining, gentlemen go have a beer. The hard lifting is mostly over and the avionics integration part can be achieved.

We have integrated Elta 2032 on Sea Harriers with Derby and on Jaguars with Harpoon. This is doable and will be done.
IFR has been achieved on other platforms. The LCA has gone through wake testing & that means it should be capable of handling IFR as well flying close in. Of course, fuel CG etc may need fixing when taking fuel while flying but they seem to be confident they can do it.

Those 40 Mk1 will come, and with Dassault pulling its shtick, and IAF running low on airframes, Mk1A is a distinct possibility.

Only thing is to make sure HAL does not get its hands on the entire program as they want. If they had proven themselves with the IJT and other programs it would be another thing. They lack the FBW and other expertise to keep this jet going with upgrades. The key thing is to have them deliver per orders and fast, with good quality.

ramana · Post by **ramana** » 20 Jun 2015 18:37

HF-24 flight trials showed gun vibrations were excessive. Solution was limit 2 out 4 guns only were fired at a time.

So gun firing ground trials are precursor to flight trials.

Radome and BVR firing are linked as radar range is based on new radome.

I agree IFR delay is trivial.

However submit LCA is unstable and hence has to be proofed by itself.

chetak, IAF is necessarily wary as foreign aircraft would have undergone a battery of tests built upon past track record. So all is not kala. HAL/ADA doesn't have latter.

RoyG · Post by **RoyG** » 20 Jun 2015 19:02

ramana wrote:HF-24 flight trials showed gun vibrations were excessive. Solution was limit 2 out 4 guns only were fired at a time.

So gun firing ground trials are precursor to flight trials.

Radome and BVR firing are linked as radar range is based on new radome.

I agree IFR delay is trivial.

However submit LCA is unstable and hence has to be proofed by itself.

chetak, IAF is necessarily wary as foreign aircraft would have undergone a battery of tests built upon past track record. So all is not kala. HAL/ADA doesn't have latter.

I was told a long time back that the vibration was an issue and that they were looking into a different gun altogether fitted in a different location of the plane. Looks like they skipped this altogether and went on with the testing.

Sanjay · Post by **Sanjay** » 20 Jun 2015 20:39

Gentlemen, let me ask a question, fundamentally has anything changed ? Is the Tejas less agile that Vivek showed us ? Is the aircraft less capable or more vulnerable than we thought ? Is the RWR a big zero ? Isn't it the case that the Derby trials and flight testing the gun firing are the issues to be demonstrated ?

ramana · Post by **ramana** » 21 Jun 2015 02:12

Sanjay, I don't know how to put it but due to constraints on size (Mig 21 replacement heritage) the plane wings/body shape is not conducive to agility. Add to that engine is under powered. So it dances like an elephant in some situations. AOA 16 vs 18 and all that.

RWR I don't know, but each RWR has to be tuned to the plane. So thats going on. Didn't hear Dr. Tamilmani give that as a milestone to be met.

Yes Derby (related to radome) and flight testing the gun are milestones.

Add IFR integration. Needed for range and payloads.
------------------
Did some looking into radomes in India. CSIR-NAL make radomes for Jaguar with Fiber glass in high temperature resin using Resin transfer matrix method.
Also made quartz fiber radomes with polyester resin.

Gap was BMI resin.

My comments:
Hence Cobham chosen.

Are on right track. Will get there eventually.

Its very experimental setup.
Location of mfg facility has effect on resin cure.

ramana · Post by **ramana** » 21 Jun 2015 02:23

Also you keep asking about J(unk) F(ighter) 17 (Copy left Shiv) and LCA.

Please compare weights and engine thrusts for both and see.

Short answer LCA is more agile based on P/W ratios alone. Not even bringing aerodynamics.

Viv S · Post by **Viv S** » 21 Jun 2015 04:24

Kartik wrote:But one good news is that Rafael's I-Derby ER missile will be the BVR missile integrated with the Mk1, with a max range of 100 kms..that will necessitate several trials with the new radome in place.

???

Why is this good news? All we need to do is bridge the gap till production Astras are available (which will likely happen by 2016). Until then the older missiles from the Navy's stocks should suffice. Why invest in a brand new variant of the Derby? If necessary, we can replace the Agat with a new Derby-derived SDR seeker in later Astra units.

On a related note, are the Tejas' outer pylons rated for a Astra-type load (150-170kgs) or are they limited to lighter loads 100-110kgs (R-73/Python-5/Derby)?

shiv · Post by **shiv** » 21 Jun 2015 07:29

Viv S wrote:
Kartik wrote:But one good news is that Rafael's I-Derby ER missile will be the BVR missile integrated with the Mk1, with a max range of 100 kms..that will necessitate several trials with the new radome in place.
???

Why is this good news? All we need to do is bridge the gap till production Astras are available (which will likely happen by 2016). Until then the older missiles from the Navy's stocks should suffice.

Well this is debatable. I would count it as good news in the sense that
1. We cannot judge if the Navy's old stocks will suffice
2. The old stocks will have to be tested anyway on the Tejas and if they are nearing their expiry date it would be a good idea to simply test newer ones
3. Do not push Astra till its trials are done. Astra will probably go on Su 30 MKI first and be proven there and then ported to other aircraft. No one seems to be complaining about Su 30 radome, so the missile can be tested on that platform

abhik · Post by **abhik** » 21 Jun 2015 10:15

^^^
The navy is not the only source of Derby missiles. I would think that the IAF would have a much larger stock Derby missile from their SPYDER SAM system.

abhik · Post by **abhik** » 21 Jun 2015 10:17

Viv S wrote:...
On a related note, are the Tejas' outer pylons rated for a Astra-type load (150-170kgs) or are they limited to lighter loads 100-110kgs (R-73/Python-5/Derby)?

They are rated at 150kg(as per this widely circulated pic), but I would guess that would mean they can really only carry SR AAMs.

srai · Post by **srai** » 21 Jun 2015 12:50

ramana wrote:Sanjay, I don't know how to put it but due to constraints on size (Mig 21 replacement heritage) the plane wings/body shape is not conducive to agility. Add to that engine is under powered. So it dances like an elephant in some situations. AOA 16 vs 18 and all that.

...

Correction: AOA is 26 degrees, which matches Mirage-2000's AOA. They are pushing that to 28 degrees. STR is around 16 d/s (2 degrees less than F-16). I think being a delta ITR is equivalent to Mirage-2000. All-in-all the agility is far superior to MiG-21.

shiv · Post by **shiv** » 21 Jun 2015 16:02

abhik wrote:^^^
The navy is not the only source of Derby missiles. I would think that the IAF would have a much larger stock Derby missile from their SPYDER SAM system.

Does anyone have information that SAM Derbys can simply be strapped on a pylon and used as AAMs?

shiv · Post by **shiv** » 21 Jun 2015 16:32

This "agility on paper" argument is totally without any sane ending.

The image below shows a bomber (the B-36) that was far more agile than fighters of its day at high altitude

The plane lasted well into the jet era. The Vulcan too was more agile than many fighters at altitude. Remember how the Jaguar does not have the agility required for sorties over mountains. I think the LCA agility story and the discussions around it are pure speculation based on paper calculations and acronyms like ITR, STR and AOA which will straightaway make 90% of people simply cock up out of fear of looking stupid.

The angle of attack (AOA) issue is in part related (I think) to high landing speeds. A higher AOA is useful here. In the old days with manual controls a test pilot could simply increase AoA and "see what happens". The problem of course is beyond some angle at some airspeed the plane will stall and then to things that may not end happily. But the entire flight profile of the LCA is software limited. In Aero India 2003 (or 2001 maybe) an early prototype did a neat half roll and then rolled back. A 360 degree roll was not completed. Disappointed, I commented on this and was informed that it was, at that time, software limited only to do a half roll and back again. No more.

A software limited AOA does not mean that a higher AOA is not possible. But there must be reasons why the last degree or two are "opened up" only slowly - avoiding the risk of stall. The Gripen continued to undergo AOA and stall tests long after induction that this was told to me by Air Marshal Rajkumar.

I think the Mongolian mentioned that a wind tunnel is simply a tube with a lot of air blowing through it and not a technological marvel. It happens that a vertical wind tunnel is also a tube with air blowing upwards into which a scale model is dropped for spin trials. It irritates me no end to hear that this has to be done in France. I can make one at home in my back room man cave - with camera and all, It can't be that difficult. What is the use of 10,000 engineering colleges and half a million graduates a year if India needs to have this done in France. Clearly a lot of money is going to line various government pockets while money is not being spent on brains and innovation. Heck its not even innovation. Its simply monkey see monkey do.

AM Rajkumar (or was it Tikoo Sen) wrote that for BAe Sea Eagle trials on Jaguars BAe said a dummy missile would cost 200,000 pounds Sterling. The simply made a dummy in India for Rs 10,000 Weird Weird stuff.