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

[bharathp]

Plans are concurrently underway for a 350-km range Astra Mark-3 as well, said the sources.

350 km A2A missile ? was this discussed here on BR before? can anyone please point me to the discussion here? thanks

[Prem Kumar]

Must be the SFDR - perhaps they are giving them all the name Astra. Could be DDM too - with Rajat Pandit, one can never be sure

[sajaym]

The Solid Fuel Ducted Ramjet is a missile propulsion system that includes a thrust modulated ducted rocket with a reduced smoke nozzle-less missile booster.[2] The thrust modulation in the system is achieved using a hot gas flow controller.[2] The system utilises a solid fuelled air-breathing ramjet engine.[1][3][4] As of 2017, the missile system has a range of about 120 kilometres at an altitude of 8 kilometres, with a speed of 2.3-2.5 Mach. This kind of a propulsion system drastically enhances the range and the speed of a missile since it does not require an oxidiser.

IMHO SFDR is not a missile, it is a propulsion system (an engine if you will) which can be put in any missile. So if SFDR technology is used in Astra, then it'll become Astra 3, if it is used in Nag then it'll become Nag 3 (or whatever). 350km is quite feasible for a ramjet-based missile.

[SSridhar]

I used to think that Astra-II was ducted ramjet based. And, the current Astra as Astra-1 while extra range (dual-pulse motor) 160 Km Astra as Astra-1 Mk.2 Nomenclatures change.

[Neela]

Its a quadruplex redundant FBW computer. Of course it will be larger than a simplified single channel FCS, in effect its 4 redundant FBW channels in one LRU. You can see the 4 discrete physical computers when you look at it from the side. Each is a FBW control system in its own right. The computers share data at 2MBPS with 512 parameters shared. The same FCS software runs at the same in all 4 channels, so 4 channel redundancy is achieved with the defective channel dropped. Having said that, technology advances and so there is a plan to make a DFCC Mk2 which is likely to be fielded on Mk1A with newer processors and will likely be more compact than this unit. However, the focus is always on reliability as versus using the latest processors etc. The DFCC has to run for at least 1000 hours considering MTBF and has achieved 5235 hours in tests.

I always imagined that the Quad FBW system to be 4 independent systems housed in different parts of the fuselage.
Any reason why damage to entire unit isnt a concern ...if it happens, then we are looking at a stone in the air.

[Kartik]

SP 23 and 24 to take to the air shortly. Others to follow in quick succession. They were taking some steps so that the availability and maintainability of the aircrafts increase significantly. That's the hold up. Not the production rate.

Meanwhile the SPJ pod is getting ready for manufacturing. 8 prototypes to be built first.

Thanks for the updates IR. I hope shortly means within 2020. HAL is really back-logged when it comes to deliveries this year. Only 2 first flights this year, of SP21 and SP22. Anantha Krishnan had written that SP23 would soon fly but since then HAL is rather quiet on the matter.

Also, wasn't the FOC itself about increased maintainability? What new steps need to be taken? It is rather disconcerting that many months after No.18 Squadron formation, they still haven't gotten more than 1 FOC Tejas delivered to them. HAL should be burning the midnight oil to stay on track and schedule. There is just too much at stake for this program and future programs to keep seeing deliveries sliding to the right.

[Kartik]

Its a quadruplex redundant FBW computer. Of course it will be larger than a simplified single channel FCS, in effect its 4 redundant FBW channels in one LRU. You can see the 4 discrete physical computers when you look at it from the side. Each is a FBW control system in its own right. The computers share data at 2MBPS with 512 parameters shared. The same FCS software runs at the same in all 4 channels, so 4 channel redundancy is achieved with the defective channel dropped. Having said that, technology advances and so there is a plan to make a DFCC Mk2 which is likely to be fielded on Mk1A with newer processors and will likely be more compact than this unit. However, the focus is always on reliability as versus using the latest processors etc. The DFCC has to run for at least 1000 hours considering MTBF and has achieved 5235 hours in tests.

Superb information as usual, Karan.

[nam]

The 350 KM Astra could be SFDR version or A2A version of NGARM.

The only thing required to make it a BVR is putting a Ku Band active seeker. Everything else, larger propellant, dual pulse motor, same flight body, warhead etc is all there.

[JTull]

Astra air combat missile to be soon tested from Tejas fighter

India’s first indigenous air-to-air missile Astra will soon be tested from the first home-grown fighter Tejas, in yet another major step towards making the weapon the mainstay of the country’s combat fleet against hostile jets in the years ahead. The integration of the Astra beyond visual range air-to-air missile (BVRAAM), which flies over four times the speed of sound at Mach 4.5, on the Tejas and the “initial ground trials” are virtually complete now. “The flight trials of the indigenous missile on the indigenous fighter will begin within the next few months,” said a source on Thursday.
...
DRDO also plans to begin testing the Mark-2 version of Astra, with a range of 160-km, in the first half of next year. Plans are concurrently underway for a 350-km range Astra Mark-3 as well, said the sources.

With impending deployment of Tejas on Western Border, this is need of the hour. There are rumours of PAF getting access to Turkish AMRAAM C-7 stocks.

[brar_w]

There are rumours of PAF getting access to Turkish AMRAAM C-7 stocks.

This will be an extremely boneheaded move by Turkey (to skirt around arms sales requirement w/o approval). With Trump on his way out, and the relationship with other NATO partners on decline acts like these may just be what triggers deeper sanctions and essentially kill any Mil-Mil partnership which will have operational and financial implications for its armed forces and defense industry. Given Turkish adventurism of late, it would also be surprising, for them to offload hardware that they may not be able to secure (new AMRAAMs) relatively quickly given all that is going on. By my count they've ordered something like 250 AIM-120C7s over the last 12 or so years which is not that large a quantity given the number of F-16's they operate.

[basant]

Can PAF F-16s launch AIM-120C7s without software upgrade from the US? Does that mean US provided software upgrade to Turkey instead of upgrading itself?

[brar_w]

Can PAF F-16s launch AIM-120C7s without software upgrade from the US? Does that mean US provided software upgrade to Turkey instead of upgrading itself?

Good point. It probably wouldn't be straightforward as it most definitely would require a software upgrade that would enable the C7. So add that to another dimension of why this would be an extremely unlikely scenario.

[Aditya_V]

US has its people on the ground where PAF bases its F-16's, plus as pointed out there will be some software blocks present from integrating C7's which will require US clearance.

Plus some Turkey's C7 given their fleet strength, conflicts with Russia, Greace etc. would have used up their life's in the air, so I dont think Turkey will have C7's to spare.

[nam]

Once Astra MK2/ SFDR starts flying, PAF will lobby US for C7. Till then US has the excuse of "maintaining strategic balance"

I am pretty sure they will put C7 as a requirement for any Afghan deal. Chances are they might get it.

Paks know PL-15 or 20 or 200 is nowhere near Aim120. China has no access to Western BVR, which India has. So IAF would have put lessons from Mica, Derby in to Astra. Chinese have no such privilege.

[kit]

Once Astra MK2/ SFDR starts flying, PAF will lobby US for C7. Till then US has the excuse of "maintaining strategic balance"

I am pretty sure they will put C7 as a requirement for any Afghan deal. Chances are they might get it.

Paks know PL-15 or 20 or 200 is nowhere near Aim120. China has no access to Western BVR, which India has. So IAF would have put lessons from Mica, Derby in to Astra. Chinese have no such privilege.

One of the reasons the US has been coy in supplying high end weapon systems to Taiwan (and Pakistan) is that the tech or weapons would fall to chinese intelligence. ( Even Japan is considered a risk ! )

[Rakesh]

https://twitter.com/VinodDX9/status/133 ... 83783?s=20 ---> An aircraft with very low RCS, equipped with ELTA 2052 AESA, Astra Mk. 1 BVRAAM, ASRAAM and showing features like HMDS, UEWS, ECM, ECCM, etc will be enoughly advanced to rule the sky.

https://twitter.com/TheWolfpackIN/statu ... 90720?s=20 ---> No doubt. And also SDRs with secure datalinks.

[JTull]

But no SPJs!

[nachiket]

But no SPJs!

Mk1A will get the EL/L-8222 pod, and eventually perhaps a downsized version of DARE's SPJ pod (hopefully).

[kit]

https://twitter.com/VinodDX9/status/1330730384292683783?s=20 ---> An aircraft with very low RCS, equipped with ELTA 2052 AESA, Astra Mk. 1 BVRAAM, ASRAAM and showing features like HMDS, UEWS, ECM, ECCM, etc will be enoughly advanced to rule the sky.

https://twitter.com/TheWolfpackIN/statu ... 90720?s=20 ---> No doubt. And also SDRs with secure datalinks.

Also 6th gen "visual stealth" ..doubt any enemy fighter pilot would be able to track it visually in a WVR fight !!

[Roop]

But no SPJs!

I think SPJs (of one kind or another) will come with Mk1A, not earlier.

Your basic point, however, is very valid -- the lack of SPJ capability is IMO the most serious operational weakness in the Tejas Mk1. The aircraft simply cannot venture into even contested (let alone hostile) airspace unescorted.

[nachiket]

Your basic point, however, is very valid -- the lack of SPJ capability is IMO the most serious operational weakness in the Tejas Mk1. The aircraft simply cannot venture into even contested (let alone hostile) airspace unescorted.

There is no reason the same pod integrated with the Mk1A can't be used on the Mk1 as well. All aircraft will get the same capability.

[Rakesh]

https://twitter.com/Kuntal__biswas/stat ... 57728?s=20 ---> Coming soon...

[putnanja]

Is there any update on how Mk1A is progressing?

[rajsunder]

Its a quadruplex redundant FBW computer. Of course it will be larger than a simplified single channel FCS, in effect its 4 redundant FBW channels in one LRU. You can see the 4 discrete physical computers when you look at it from the side. Each is a FBW control system in its own right. The computers share data at 2MBPS with 512 parameters shared. The same FCS software runs at the same in all 4 channels, so 4 channel redundancy is achieved with the defective channel dropped. Having said that, technology advances and so there is a plan to make a DFCC Mk2 which is likely to be fielded on Mk1A with newer processors and will likely be more compact than this unit. However, the focus is always on reliability as versus using the latest processors etc. The DFCC has to run for at least 1000 hours considering MTBF and has achieved 5235 hours in tests.

I always imagined that the Quad FBW system to be 4 independent systems housed in different parts of the fuselage.
Any reason why damage to entire unit isnt a concern ...if it happens, then we are looking at a stone in the air.

I used to think that since it is a quad redundant FBW system, there would be four different computers placed at four different places on the fighter jet, to allow for loss due to a stray hit during war.

[Mort Walker]

I always imagined that the Quad FBW system to be 4 independent systems housed in different parts of the fuselage.
Any reason why damage to entire unit isnt a concern ...if it happens, then we are looking at a stone in the air.

I used to think that since it is a quad redundant FBW system, there would be four different computers placed at four different places on the fighter jet, to allow for loss due to a stray hit during war.

No. All of the data paths and power supplies to the flight computer already have redundancy. By placing the flight computers in different locations would add electro mechanical complexity and increase weight. Stray hits can happen, in low level flying, but if you're in combat zone and someone gets a missile lock on you, then you're done.

[JayS]

There is a mention of a lesson that ADA got from BAE for testing of the Quad FBW in the book The Tejas Story. ADA was struggling when BAE told them they never test conditions like 3 channels out of 4 gone, because if the airceaft is damaged to that extent then you are anyway gonna bail out, so why waste time in testing for designing and testing the system for such conditions at all..?

Similarly I'd imagine, If the FCS computer, which is buried inside, is hit, you are probably gonna bail out anyway. So no point in desinging separate LRUs. You have to draw lines while desining systems. A lot of these lessons come from experience, you observe in so many yrs such condition never encountered, then you drop it as a requirement.

[Rakesh]

https://twitter.com/strategic_front/sta ... 19776?s=20 ---> Pre-flight check being performed on a HAL Tejas by an IAF pilot. This pre-flight procedure is used by almost all militaries across the world before starting the engine on the aircraft.

[rajsunder]

There is a mention of a lesson that ADA got from BAE for testing of the Quad FBW in the book The Tejas Story. ADA was struggling when BAE told them they never test conditions like 3 channels out of 4 gone, because if the airceaft is damaged to that extent then you are anyway gonna bail out, so why waste time in testing for designing and testing the system for such conditions at all..?

Similarly I'd imagine, If the FCS computer, which is buried inside, is hit, you are probably gonna bail out anyway. So no point in designing separate LRUs. You have to draw lines while designing systems. A lot of these lessons come from experience, you observe in so many yrs such condition never encountered, then you drop it as a requirement.

I was reading this article about F-15 QX on thedrive blog, while describing the new FBW system it said

The aim of bringing fly-by-wire to the F-15 was threefold. Reliability, redundancy, and performance. “From a reliability perspective, you have two flight control computers, and each has two channels, plus quadruple inputs to each of the flight control surfaces. A quad-redundant flight control system from the flight control computers to the stabilators provides very high levels of reliability.

Is this similar to our LCA? 1 computer 4 channels for LCA and 2 computers 2 channels each for F-15, but F-15 has four separate input channels to each of the control surfaces. What is our design on LCA?

[brar_w]

There are different approaches utilized depending upon a a host of trades made during the design phase. Some have to do with what works given platform limitations while others rely on what can be leveraged from other programs that make adoption the preferred approach to something new. So Boeing went in for two flight control systems (which they've done on other FBW applications on fighter applications elsewhere) as opposed to the classic quad redundant flight control computer or more than 2. Lockheed on the F-35 put three separate computers for survivability. Again, you work within what you can do given other design constraints and how much flexibility you have. Different choices but it doesn't mean one choice that may be used in one instance is superior to another choice made elsewhere in another instance.

[Roop]

https://twitter.com/strategic_front/sta ... 19776?s=20 ---> Pre-flight check being performed on a HAL Tejas by an IAF pilot. This pre-flight procedure is used by almost all militaries across the world before starting the engine on the aircraft.

Not just militaries. Commercial airline pilots do the same pre-flight checks.

[Yagnasri]

Looks like the 83 LCA Mk1A deal will be signed by this month end itself.

[Aditya_V]

This month is supposed to be the deadline, any basis that it will actually be ahered to?

[chola]

^^^ Don't be surprised if the signing be delayed a bit. Budget might need to be rebalanced after emergency orders of 21 MiG-29s and kits for 12 SU-30s from Russ.

[nachiket]

^^^ Don't be surprised if the signing be delayed a bit. Budget might need to be rebalanced after emergency orders of 21 MiG-29s and kits for 12 SU-30s from Russ.

Those orders have not been signed yet, although acquisition has been cleared.

[Rakesh]

Looks like the 83 LCA Mk1A deal will be signed by this month end itself.

Did you read this somewhere? Any link?

^^^ Don't be surprised if the signing be delayed a bit. Budget might need to be rebalanced after emergency orders of 21 MiG-29s and kits for 12 SU-30s from Russ.

The MoD best be ordering the 83 Tejas Mk1As before the 21 MiG-29s and 12 Su-30MKIs or any other fighter. They stated the order will be placed by Dec 2020.

[chola]

^^^ Don't be surprised if the signing be delayed a bit. Budget might need to be rebalanced after emergency orders of 21 MiG-29s and kits for 12 SU-30s from Russ.

Those orders have not been signed yet, although acquisition has been cleared.

Yes, both the Russian orders (might include KA-31s too) and the 83 Tejas are at the same state in the procedural pipeline -- MoD, DAC (aquisition council) and the possibly very long steps to the CCS (cabinet committee security) staffed by the powers that be in New Dehli who actually approves and release funding.

Putin and Modi had said they want to sign those contracts soon during the height of the dust up with Cheen and those orders were seen as critical emergency buys. So where do you think the pressure will come from? If the budget is restricted who do you think will get first dibs?

That's why I caution that we might see delay though I hope not. But if it is a toss up between Russia and HAL, I have a feeling that both the powers at R Bhavan and the IAF would rather pay Russia first over HAL.

[ramana]

Looks like the 83 LCA Mk1A deal will be signed by this month end itself.

Yes. I too heard that. Second or third week December

[Rakesh]

https://twitter.com/thewolfpackin/statu ... 94562?s=21 —> India's HAL offers to sale US Navy Tejas-LIFT (previously known as Tejas Sport) for US Navy's fighter trainer program (Undergraduate Jet Training System). The aircraft will be based on Tejas Mk1A and a demonstrator will be build if shortlisted.

[Rakesh]

https://twitter.com/thewolfpackin/statu ... 81925?s=21 —> Tejas has a major advantage as it is the only potential contender to have successfully demonstrated carrier capability.

[Rakesh]

Role reversal: India offers US fighter jet trainer in 1st major defence sales pitch
https://m.economictimes.com/news/defenc ... 635249.cms