GTRE GTX 35VS Kaveri

[pipebomb]

View: https://www.youtube.com/live/_pWc1Hy-wTg?si=YPhSiu7l0anSlTSz

So what I got from saurav jha's recent past couple of episodes of IAH is

1) The only thing we lack compared to GE, Safran etc is DATA, which they aquire through years of iterative development, flying and productionizing. And no amount of TOT is going to help bridge this gap. THERE ARE NO SHORTCUTS

2) GTRE has solved all the teething issue of kaveri and has been waiting for govt nod to integrate it to LCA

3) Kaveri has aachieved it's dry thrust goal of 50kn but missed it's wet thrust and currently stands at 76kn. It is also overweight by a couple of hundred kgs

4) GTRE and it's indutrial patners has the technological capability/capacity to achieve the 80kn wet thrust without changing kaveri's core. The end result will still be overweight compared to f404 but not by much

So what's the best way to move forward in our complex Indian scenario

To me the path with least resistance, least time, least capex expenditure or r&d cost in productionizing an Indian TF engine, is replacing f414 in TEDBF with kaveri

1) TEDBF with twin kaveri satisfy every parameter of IN carrier aircraft requirement

2) It will be safer to put kaveri in a twin engine aircraft rather than lca

3) IN is already hedging it's carrier aircraft bet by importing Rafales. So there should be no problem in backing TEDBF powered by kaveri

4) Iterative development won't work without productionizing an Indian TF engine first

 

[Azaad]

So what I got from saurav jha's recent past couple of episodes of IAH is

1) The only thing we lack compared to GE, Safran etc is DATA, which they aquire through years of iterative development, flying and productionizing. And no amount of TOT is going to help bridge this gap. THERE ARE NO SHORTCUTS

2) GTRE has solved all the teething issue of kaveri and has been waiting for govt nod to integrate it to LCA

3) Kaveri has aachieved it's dry thrust goal of 50kn but missed it's wet thrust and currently stands at 76kn. It is also overweight by a couple of hundred kgs

4) GTRE and it's indutrial patners has the technological capability/capacity to achieve the 80kn wet thrust without changing kaveri's core. The end result will still be overweight compared to f404 but not by much

So what's the best way to move forward in our complex Indian scenario

To me the path with least resistance, least time, least capex expenditure or r&d cost in productionizing an Indian TF engine, is replacing f414 in TEDBF with kaveri

1) TEDBF with twin kaveri satisfy every parameter of IN carrier aircraft requirement

2) It will be safer to put kaveri in a twin engine aircraft rather than lca

3) IN is already hedging it's carrier aircraft bet by importing Rafales. So there should be no problem in backing TEDBF powered by kaveri

4) Iterative development won't work without productionizing an Indian TF engine first

The plan for Kaveri ( it's derivatives & iterations) are somewhat like this - 46-48KN KED / Dry Kaveri tests ( if successful ?) -> 75 KN Kaveri ( if successful?) -> 90 KN Kaveri.

To achieve this much we'd need 10 years & a whole lot of testing infrastructure apart from money to finance the program.

It's only after we achieve this much we can move to the 100-105 KN Kaveri analogous to the GE F-414 which'd require a brand new core. That's a post 2035 program .

In brief, all these programs are geared to come up with a TF during MLU of the LCA Mk-1/ Mk-1a / Mk-2, the AMCA Mk-1 & the TEDBF. That's the road map or at least that's how it should be, looking at it from where we are .

 

[pipebomb]

The plan for Kaveri ( it's derivatives & iterations) are somewhat like this - 46-48KN KED / Dry Kaveri tests ( if successful ?) -> 75 KN Kaveri ( if successful?) -> 90 KN Kaveri.

To achieve this much we'd need 10 years & a whole lot of testing infrastructure apart from money to finance the program.

It's only after we achieve this much we can move to the 100-105 KN Kaveri analogous to the GE F-414 which'd require a brand new core. That's a post 2035 program .

In brief, all these programs are geared to come up with a TF during MLU of the LCA Mk-1/ Mk-1a / Mk-2, the AMCA Mk-1 & the TEDBF. That's the road map or at least that's how it should be, looking at it from where we are .

But we don't have 10yrs. When the 90kn derivative is ready we Integrate it to mk2 & tdbf

But we need to put the 76-80kn Kaveri in production. Design TDFB around it. Don't wait for any future derivative

 

[Anants]

3) Kaveri has aachieved it's dry thrust goal of 50kn but missed it's wet thrust and currently stands at 76kn. It is also overweight by a couple of hundred kgs

50 Kn was Achieved at cost of very low MTBF ofn100 hrs IIRC read at some tweet. So it's going to be 46 45 kn for decent MTBF

4) GTRE and it's indutrial patners has the technological capability/capacity to achieve the 80kn wet thrust without changing kaveri's core. The end result will still be overweight compared to f404 but not by much

So what's the best way to move forward in our complex Indian scenario

To me the path with least resistance, least time, least capex expenditure or r&d cost in productionizing an Indian TF engine, is replacing f414 in TEDBF with kaveri

1) TEDBF with twin kaveri satisfy every parameter of IN carrier aircraft requirement

2) It will be safer to put kaveri in a twin engine aircraft rather than lca

3) IN is already hedging it's carrier aircraft bet by importing Rafales. So there should be no problem in backing TEDBF powered by kaveri

4) Iterative development won't work without productionizing an Indian TF engine first

What is most required is HATF and FTB, otherwise all plans are just air castle and an exercise in pain and agony without any gains

 

[Anants]

The plan for Kaveri ( it's derivatives & iterations) are somewhat like this - 46-48KN KED / Dry Kaveri tests ( if successful ?) -> 75 KN Kaveri ( if successful?) -> 90 KN Kaveri

45/73 kn was already Achieved decade back, why do they want to reinvent wheel here by again trying to achieve same figures.

It's only after we achieve this much we can move to the 100-105 KN Kaveri analogous to the GE F-414 which'd require a brand new core. That's a post 2035 program .

This program should start now and only then you would have base to work upon in 2035, otherwise you are again seeing two decade development work post 2035

In brief, all these programs are geared to come up with a TF during MLU of the LCA Mk-1/ Mk-1a / Mk-2, the AMCA Mk-1 & the TEDBF. That's the road map or at least that's how it should be, looking at it from where we are .

As If IAF shall happily accept it. Mark my words, IAF shall rather ground LCA than house Kaveri on it. Even by God's grace they do, a single crash would be en9ugh for them to mothball LCA program like Marut.

 

[Blademaster]

45/73 kn was already Achieved decade back, why do they want to reinvent wheel here by again trying to achieve same figures.

Because Safran told them that it was the only way to resolve the screeching and instability at high RPMs and extend the MTBO.

This program should start now and only then you would have base to work upon in 2035, otherwise you are again seeing two decade development work post 2035


As If IAF shall happily accept it. Mark my words, IAF shall rather ground LCA than house Kaveri on it. Even by God's grace they do, a single crash would be en9ugh for them to mothball LCA program like Marut.

We need to replace the IAF brass with the brass that would keep supporting the LCA no matter what.

 

[Azaad]

But we don't have 10yrs. When the 90kn derivative is ready we Integrate it to mk2 & tdbf

Who says we don't have a decade? What do you think the ToT & local mfg program for the GE F-414 is all about?

It's to get mfg technology & knowledge, insulate our FA development program to the extent possible from US whimsicality & to get those FAs in the air ASAP avoiding delays which have plagued all our FA programs till date.

Why would GE consent to the entire agreement if the qty was so low?

But we need to put the 76-80kn Kaveri in production. Design TDFB around it. Don't wait for any future derivative

First we need to validate the Dry Kaveri. That in itself would take a year or 2 . Then we need to mate the AFB version to this Dry Kaveri & get it tested on board an FTB. That process would take us a good 5 years at least.

Once that's validated we productionize it. It's only after that we move to the 100-105 KN TF program. Even if we accomplish all this in a decade beginning now, it'd signify smooth sailing which in itself would be good news as it means our tech has now reached maturity.

Moreover, a 90 KN TF in a decade being in production would come around the time of the MLU of the Mk-1a we were to induct in the IAF last year.

That's how this entire program of Kaveri, its derivatives & iterations was conceived & it's sound in logic. Even if we stick to it & it delivers in the time lines it was expected to we'd have achieved our goals. No point being over ambitious.

We're already paying a price for it by conceiving a 4th Gen FA & a 4th Gen TF from ground up with no experience, no great R&D set up, no industrial depth & on & on when we launched the Kaveri & the LCA program in the early 80s & the results are before you.

What you're suggesting is we go down that path again .

 

[Azaad]

45/73 kn was already Achieved decade back, why do they want to reinvent wheel here by again trying to achieve same figures.

That 75 KN ouput couldn't be tested for an extended period of time due to issues. Hence we needed guidance, therefore SAFRAN consultancy in 2018. You know the rest.

This program should start now and only then you would have base to work upon in 2035, otherwise you are again seeing two decade development work post 2035

What we've now is a redesigned version based on that consultancy, realisation of new materials, etc. It needs to be validated, hence testing & certification before moving on to the 100 KN TF+ project .

As If IAF shall happily accept it. Mark my words, IAF shall rather ground LCA than house Kaveri on it. Even by God's grace they do, a single crash would be en9ugh for them to mothball LCA program like Marut.

I don't think this assumption holds true today. The road map I've detailed couldn't be possible without their participation & ascent

 

[Anants]

All good but Kaveri is 3.5. Not 4th. One blinks, tbc, sx gets Integrated and we achieve core temp of 1700 - we can call it 4th gen.

 

[shade2]

We need to replace the IAF brass with the brass that would keep supporting the LCA no matter what.

As If IAF shall happily accept it. Mark my words, IAF shall rather ground LCA than house Kaveri on it. Even by God's grace they do, a single crash would be en9ugh for them to mothball LCA program like Marut.

They have a closed loop system for promotions and all afaik just like the Milaards
This is not like the Babudom where the political class can appoint certain replacements.

Change has to come from within, they have to make their peace with the model of large orders for IDDM jets and engines and take active part in the development process like the Navy does with their ships.

 

[Anants]

I don't think this assumption holds true today. The road map I've detailed couldn't be possible without their participation & ascent

We have tried similar approach before too with Marut for reengining. Problem with this approach is a lot depends on goodwill of
a)forgien collaborator
b) Govt of the day
c) Budget allocation
d) Airforce

At any time any one them could pull the rug. Just like in Marut Case. Kabini core was result of the cumulative research for Marut engine exercise. At that time too they were thinking advanced AMCA kind of succesor for Marut in form of HF 24. We know what happened.

Till we have a pro indigenization consisitent national defence policy just like 5 year plans. Indian Story in local aviation shall remain same more or less

 

[Azaad]

We have tried similar approach before too with Marut for reengining. Problem with this approach is a lot depends on goodwill of
a)forgien collaborator
b) Govt of the day
c) Budget allocation
d) Airforce

That's true of every foreign collaboration not just the F-414 or the forthcoming JV to develop a 120 KN TF.

The other conditions also hold true for any program - domestic or foreign.

I think there's a realisation more than ever in the GoI & MoD that they've goofed up massively when it comes to the IAF & its various programs not that IAF itself is blameless be it ACM Chaudhari's adamant attitude w.r.t to tendering MRFA instead of piece meal procurement of Rafales or their attitude w.r.t the LCA program. IAF too realise their blunder.

For all the blame we lay at HAL's door , not that they're blameless , let's not forget that productionizing a new item of the complexity of a 4.5 Gen FA involves complexities of a different order of magnitude especially given the fact that HAL up until that point in time was a production agency used to assembling out of a CKD or SKD.

All local developments involved mostly Indigenization of consumables mfgd from given engineering drawings by the OEM. The LCA was a different beast altogether.

To add to the complexity back in the day IAF & ADA got into a via media where 20 would be mfgd as per IOC specifications & 20 as per FOC specifications which came in 2019 . Then you had the Wuhan virus pandemic .

Also check for how long did it take to ink the agreement for the Mk-1a & when was the order released. IIRC , it took 3 yrs of negotiations . Then came news only 32 FAs would be mfgd & 8 nos trainers would be combined with 10 nos trainers which would be built as per Mk-1 FOC specifications.

How do you go about developing vendors in such a scenario & negotiate on price with them for such meager quantities ?

At any time any one them could pull the rug. Just like in Marut Case. Kabini core was result of the cumulative research for Marut engine exercise.

This is the first time I've come across news the Kabini core is based on studies conducted for the Marut TF

At that time too they were thinking advanced AMCA kind of succesor for Marut in form of HF 24. We know what happened.

Lots of versions. According to some MoD sabotaged it , as per some Dr Kurt Tank and / or his team did it , as per some the IAF did it & finally it was the Brits.

The most popular version is the Brits asked for an equivalent of ~ INR 5 cr to develop a new TF which'd be a perfect fit for the Marut which MoD or MoF denied funds for by which time the Soviets agreed to ToT for the MiG -21 & the Brit proposal was dropped.

We even explored the possibility of tying up with Egypt given the bonhomie between Nasser & Nehru who had a TF development program in collaboration with an European country ( don't recall if it was Germany or France or even UK ) which didn't go anywhere coz the TF program itself didn't materialise between Egypt & that European country.

No point going over Marut as of now.

Till we have a pro indigenization consisitent national defence policy just like 5 year plans. Indian Story in local aviation shall remain same more or less

Agreed.

 

[Anants]

@Azaad read about GTX 37-14U It was meant for HF 73 which was based on Marut (like orca is to LCA). What I wanted to write was Marut++. From GTX 37-14U we got GTX 35 was turbofan version of GTX 37-14U. But it's performance was unsatisfactory. So they developed GTX35VS which is Kaveri. And we know even Kaveri did not meet criteria. And whatever KDE based Turbofan we are dreaming of shall meet same fate.

 

[Azaad]

@Azaad read about GTX 37-14U It was meant for HF 73 which was based on Marut (like orca is to LCA). What I wanted to write was Marut++. From GTX 37-14U we got GTX 35 was turbofan version of GTX 37-14U. But it's performance was unsatisfactory. So they developed GTX35VS which is Kaveri. And we know even Kaveri did not meet criteria. And whatever KDE based Turbofan we are dreaming of shall meet same fate.

We got the GTX37-14UB from GTX37-14 U which was a turbojet. The former was supposed to be the TF version which failed. Initially the Kabini was made up from this same core. That was dropped long ago

 

[Anants]

We got the GTX37-14UB from GTX37-14 U which was a turbojet. The former was supposed to be the TF version which failed. Initially the Kabini was made up from this same core. That was dropped long ago

Nope


The GTX-37-14U augmented turbojet is the initial GTX-35 engine variant. Development began in 1977. This model was quickly supplanted by other variants with different designs. GTX-37-14UB. The GTX-37-14UB is a turbofan variant based on the original turbojet core; it has a bypass ratio of 0.2:1. The variant was rated at over 20,000 lbst (89 kN). Originally proposed for the LCA, this engine variant was not selected owing to its large frontal area. GTX-35. The GTX-35 is the straight turbojet, initially intended for the LCA. This variant was not selected.either, due to its very high specific fuel consumption (SFC). The GTX-35VS (Kaveri) engine (also referred to as the GTX-35V) is an improved turbofan engine designed for use in the production-standard LCA aircraft.

 

[Azaad]

Nope


The GTX-37-14U augmented turbojet is the initial GTX-35 engine variant. Development began in 1977. This model was quickly supplanted by other variants with different designs. GTX-37-14UB. The GTX-37-14UB is a turbofan variant based on the original turbojet core; it has a bypass ratio of 0.2:1. The variant was rated at over 20,000 lbst (89 kN). Originally proposed for the LCA, this engine variant was not selected owing to its large frontal area. GTX-35. The GTX-35 is the straight turbojet, initially intended for the LCA. This variant was not selected.either, due to its very high specific fuel consumption (SFC). The GTX-35VS (Kaveri) engine (also referred to as the GTX-35V) is an improved turbofan engine designed for use in the production-standard LCA aircraft.

What exactly is the point you wish to make ? I'm confused. You seem to be all over the place from expressing apprehensions on the future of the Kaveri to the origins of the Kaveri.

 

[Anants]

What exactly is the point you wish to make ? I'm confused. You seem to be all over the place from expressing apprehensions on the future of the Kaveri to the origins of the Kaveri.

Nothing but simply countering your statement that Kaveri is not an evolution of the GTX series. GTX-35VS is what became Kaveri, which is an improved version of GTX-35.

Apprehension I already gave my point earlier. An additional point is that even with a thrust factor (TF) of 46/75 kN, it may meet the same fate as the early GTX engines due to performance shortfalls. Even if Kaveri achieves thrust figures comparable to the F404, increased weight would make it unacceptable. This mirrors the inadequacy of the F404, which failed to make the LCA a true 9G aircraft. This shortfall led to the initial Mk2 being designed as a slightly elongated LCA Mk1 powered by the F414.

The only faint hope for Kaveri lies in its potential use in TEDBF. But if a GE engine factory is established in India, the Navy will likely demand the F414 for TEDBF due to its proven reliability and performance.

 

[Azaad]

Nothing but simply countering your statement that Kaveri is not an evolution of the GTX series. GTX-35VS is what became Kaveri, which is an improved version of GTX-35.

But where did I dispute the Kaveri is not an evolution of the GTX design. It's evident in the nomenclature isn't it. You suggested the Kabini was from the earlier GTX37-14U TurboJet Engine or something to that effect which it actually was before they re engineered the core.

The Kabini you have today bears little resemblance to the earlier version unless of course you're arguing it's an iteration which it is.

Apprehension I already gave my point earlier. An additional point is that even with a thrust factor (TF) of 46/75 kN, it may meet the same fate as the early GTX engines due to performance shortfalls.

Let's wait for the test results to be out.

Even if Kaveri achieves thrust figures comparable to the F404, increased weight would make it unacceptable. This mirrors the inadequacy of the F404, which failed to make the LCA a true 9G aircraft. This shortfall led to the initial Mk2 being designed as a slightly elongated LCA Mk1 powered by the F414.

From what I understand the LCA Mk-1 in the shape we have it was designed for the Kaveri WITH its excess weight ~ 1500 kgs. In order to accommodate the F-404 they had to incorporate ballasts.

Now with the reduction in weight as per Decklander , even if the GTRE can they probably won't go below 1100 kgs & would like whatever derivative of the Kaveri which goes into the LCA during MLU to be ideally around ~ 1200 kgs else they'd have to undertake some modifications with the design , rewrite FCL etc.

So ironically there's a disincentive to go below a certain weight believe it or not.

The only faint hope for Kaveri lies in its potential use in TEDBF. But if a GE engine factory is established in India, the Navy will likely demand the F414 for TEDBF due to its proven reliability and performance.

The GE JV is taking place in the first place because LCA Mk-2 , AMCA Mk-1 & Mk-2 ( in the initial test phase & as a back up in case the JV is late or fails to deliver an adequate TF ) & the TEDBF will be equipped with the F-414 TF.

There was never any hope or even news to the effect the Kaveri would go into the TEDBF in its testing phase or even later in production.

We're ( as in a number of informed commentators on Twitter , BRF & people like S.Jha ) speculating that once the 90 KN Kaveri TF is successful , in all likelihood they'd go in for the 100-105 KN based on the Kaveri design. It could also be a derivative of the 120 KN from the JV we are scheduled to undertake but that'd call for royalties etc . Hence the Kaveri derivative.

 

[Anants]

But where did I dispute the Kaveri is not an evolution of the GTX design. It's evident in the nomenclature isn't it. You suggested the Kabini was from the earlier GTX37-14U TurboJet Engine or something to that effect which it actually was before they re engineered the core..

This is what I wrote originally and that is what I elaborated again. Confusi9n came where you said grx core based kabini was dropped altogether. I was elaborating, it was not dropped but evolved.

[USER=76]@Azaad[/USER] read about GTX 37-14U It was meant for HF 73 which was based on Marut (like orca is to LCA). What I wanted to write was Marut++. From GTX 37-14U we got GTX 35 was turbofan version of GTX 37-14U. But it's performance was unsatisfactory. So they developed GTX35VS which is Kaveri. And we know even Kaveri did not meet criteria. And whatever KDE based Turbofan we are dreaming of shall meet same fate.
.

Let's wait for the test results to be out.

Sure , l hope and pray it happens within half decade

From what I understand the LCA Mk-1 in the shape we have it was designed for the Kaveri WITH its excess weight ~ 1500 kgs. In order to accommodate the F-404 they had to incorporate ballasts.

agree. but much of ballast were removed once ifr and radar got added, You had LCA tejas gaining weight along with mission creep. Thats why even 404 IN felt inadequate to make tejas 9g.

Now with the reduction in weight as per Decklander , even if the GTRE can they probably won't go below 1100 kgs & would like whatever derivative of the Kaveri which goes into the LCA during MLU to be ideally around ~ 1200 kgs else they'd have to undertake some modifications with the design , rewrite FCL etc.

So ironically there's a disincentive to go below a certain weight believe it or not.

Yes I can see and understand. But my point stays valid with future Kaveri (90kn) , Tejas shall either have reduced take off weight by approx 200 kg to retain same performance as GE404 or accept reduced performance.

The GE JV is taking place in the first place because LCA Mk-2 , AMCA Mk-1 & Mk-2 ( in the initial test phase & as a back up in case the JV is late or fails to deliver an adequate TF ) & the TEDBF will be equipped with the F-414 TF.

There was never any hope or even news to the effect the Kaveri would go into the TEDBF in its testing phase or even later in production.

We're ( as in a number of informed commentators on Twitter , BRF & people like S.Jha ) speculating that once the 90 KN Kaveri TF is successful , in all likelihood they'd go in for the 100-105 KN based on the Kaveri design. It could also be a derivative of the 120 KN from the JV we are scheduled to undertake but that'd call for royalties etc . Hence the Kaveri derivative.

Sjha mentioned that TEBDF easily take in KDE TF engines and they should take. Rest agreed.