Kaveri & Aero-Engine: News & Discussion

[drnayar]

So, to reduce foreign dependence, we are embarking on 2 multi-billion, decade-long projects with 2 foreign vendors

To reduce the risk of being dependent on one foreign supplier, India is embarking on projects with two foreign suppliers.

IMO, if there are resources available, then India should also embark on a third project with the Russians. But that may be stretching it too thin.

Why are you leaving out the Japs?

In the true spirit of Atmanirbhar and Sabke Saath, Sabka Vikas we need to help Japan to build up their aerospace industry

[uddu]

This collaboration with Brahmos should have occurred long ago. The program manager for Kaveri was sleeping. Sometimes the solutions are within and identifying them is their job. Anyways we are back to certification and testing the engine, how much more wasted time on this activity due to videshi test facilities. This should make the MOD babus sanction the appropriate test facilities including an aircraft with 4 engines. A GE Ohio like test facility for environment level testing is required. BTW bird hit testing is a requirement of certification and so are things like hail, storm dust, rain and so forth.

Regarding test facilities, the call should be taken by NaMo and Rajnath Singh. Here there is no third party involvement or objection to be raised. It's a test facility for DRDO. Should be given. I don't think any service chief will intrude himself and say, don't set up test facility.

[Rakesh]

A must read thread on X on the development (or the lack thereof!) of turbofans in India.

https://x.com/AnchitGupta9/status/20286 ... 15666?s=20 ---> I have been following the GTRE/ Kaveri Engine discussions intently. Before we go further, remember the Indian Air Force officer who started this journey: Air Vice Marshal Sailendra Nath Roy Chaudhury. Because he built the starting line. (1/25)

Twitter Thread on one page ---> https://twitter-thread.com/t/2028676383795515666

[S_Madhukar]

Sabka Saath Sabka Vishwas , time kharab to Sabki Laath

[Kanoji]

https://x.com/nitingokhale/status/2030095773329936897
@nitingokhale
Well said Sushant

https://x.com/sushantsareen/status/2029766075299287100
@sushantsareen
If only Indian twitterati and commentariat werent such snowflakes they would realise that China's rise was its own doing. It's rise was not an American gift. The Chinese planned well, worked well, their engineers didnt sell soap, coke or maggi or join the IAS or worse IRS. They innovated, they built, they invested, they educated their people. The Chinese miracle is of their own making. Similarly whether India will rise or not is in Indian hands. If India rises it wont be because the Americans or Europeans allowed us to or gifted it to us. And we will never rise as long as our first talking point with other countries is "transfer of tech". This is the height of imagination and profoundity of the Indian bureaucrat and techno-crat. Big powers will never allow anyone to equal them. That is a no brainer. If India has to rise, we will on our own genius or not at all. And we will have to find our own way to rise. We cant copy someone else. We must learn from others (assuming we understand we are not the repository of all wisdom in the world and get off our hobbyhorse of being vishvaguru) but we must find our own way to the top because every country has to find its own path.

Posting this here as this mindset is very much needed in the stakeholders responsible for the development of Kaveri and making India Atmanirbhar in jet engines.

[uddu]

A must read thread on X on the development (or the lack thereof!) of turbofans in India.

https://x.com/AnchitGupta9/status/20286 ... 15666?s=20 ---> I have been following the GTRE/ Kaveri Engine discussions intently. Before we go further, remember the Indian Air Force officer who started this journey: Air Vice Marshal Sailendra Nath Roy Chaudhury. Because he built the starting line. (1/25)

Twitter Thread on one page ---> https://twitter-thread.com/t/2028676383795515666

Sirji, who started is not issue here. Who completes it need to be discussed so that we can have an engine. We must be looking at who is taking responsibility for it today. If Rajnath singh and Shriman Modi is not doing their responsibility in ensuring HATF, then IAF chief can demand that the ministry approve the same. IAF Chief can make public statement to come in support of DRDO needs. He can simply state that we are looking at the HATF being approved by the government and hopefully soon, so that DRDO can speed up the Kaveri engine project not needing to Russia every time and take it to its conclusion.

[vera_k]

That thread is instructive. It looks like a clash of personalities, with a new administration abandoning old work on the GTX engine that was being incubated. Wonder if we're seeing a repeat of this now, with new engine programs being spun up, while the old one with Kaveri has not been completed.

[uddu]

it's understandable that the HLFT-42 is heavier with not using composites to keep the cost low. HAL should not be going for GE engines when it comes to HLFT-42. The reason being we again will have issues importing and relying on a foreign players. Since Kaveri cannot be used for the HLFT-42 needing more thrust for its weight and such, the best option is a derated variant of the 120KN engine in development. Otherwise, how much will be the profit margin in selling a desi fighter with a foreign engine and with limited availability etc, there is not much profit to be made and competition with foreign players become tough. Hope they choose the right Joint venture engine and ensure HLFT-42 is suitable for that. At any stage more power requirements are needed, the same 120KN engine can be used. Else the nation should be putting the money right now in the development of a desi Kaveri 2.0 that is similar in performance to F-414 based on the technology available with the current Kaveri

HAL Seeks 95-100kN Engine for HLFT-42 Trainer to Align with Tejas Mk2, Sidelining Kaveri for Primary Role
https://defence.in/threads/hal-seeks-95 ... ole.17111/
08 March 2026

By selecting an engine in the 100kN class, HAL is prioritizing operational commonality. This thrust range aligns perfectly with the General Electric F414-INS6 engine, which India has already cleared for local production through a major technology transfer agreement.

[Kailash]

Hlft42 ? Does HAL have the manpower to pull this off in time? This whole thing doesn't fit. Bae hawk that it is designed to replace is much smaller and far less capable than hlft42. This is a jf17 bandar equivalent of a mk2. Again feels like IAF wants a full fledged fighter but willing to pay only trainer prices.

It is not going with an indigenous engine - be it kaveri which is overweight and underpowered or a reverse engineered al31/ganga. So no strategic independence. Russian 177s or the Japanese xf9 or any clean slate design from RR only continued the import dependence, limited export options.

If it is based on a 120kn safran/gtre engine that'll get ready in 7-10 years time, it is already too late. Not to mention new airframe with new engine conundrum.

Only Kaveri/Ganga makes sense. May be this decision should be guided by good economic sense and historic track record of HAL. Really only two questions..

• How soon can they churn out the hlft42 , while maintaining mk1a/mk2 production rates?

• How cheap will it be to buy maintain and upgrade compared to mk2

[uddu]

DRDO Plans to Integrate Indigenous 5th-Gen Single-Crystal Metallurgy into Planned 120 kN AMCA Engine with Safran
https://defence.in/threads/drdo-plans-t ... ran.17132/
11-3-2026

(DMRL). Indian scientists initially developed a "directionally solidified" alloy known as DMD4.

While single-crystal blades are the gold standard, they are notoriously difficult and expensive to cast into complex shapes. DMD4 served as a sophisticated solution, offering high reliability and easier manufacturing for intricate engine geometries.

By iterating on this design and adding rare elements like ruthenium (Ru), researchers significantly improved the material's heat resistance and durability.

While France’s Safran brings world-class experience in core engine architecture, India's contribution of indigenous blade metallurgy ensures the partnership is a balanced collaboration.

This "division of labour" allows India to retain control over the "hot section" of the engine—the most critical and sensitive part of propulsion technology.

[Rakesh]

...

Saar, that Defence.in article is fake news. There is no HLFT-42 coming for the IAF.

IDRW.org and Defence.in are fake news websites designed to fool the public for the sole purpose of website clicks.

[Rakesh]

Sirji, who started is not issue here. Who completes it need to be discussed so that we can have an engine. We must be looking at who is taking responsibility for it today. If Rajnath singh and Shriman Modi is not doing their responsibility in ensuring HATF, then IAF chief can demand that the ministry approve the same. IAF Chief can make public statement to come in support of DRDO needs. He can simply state that we are looking at the HATF being approved by the government and hopefully soon, so that DRDO can speed up the Kaveri engine project not needing to Russia every time and take it to its conclusion.

Nobody is completing it uddu. There is no responsibility towards this.

IAF Chief and Air HQ is focused on completing the MRFA deal. Engine development is the last thing on their minds. All the speeches of Atmanirbharata is meant solely for public consumption. The demonstrated actions are opposite to the speeches.

[Rakesh]

https://x.com/Tej_Intel/status/2031630769161212092?s=20 ---> For students thinking of getting into aero-engine, join Gatishakti University for aero-engine MRO - supported by Safran.

Wiki Page ---> https://en.wikipedia.org/wiki/Gati_Shak ... avidyalaya

[ritesh]

News doing rounds on twitter, kaveri with modified afterburner put out 81kn. Can we hope it to power Tejas mk1a anytime soon?
https://x.com/HemanNamo/status/2025902791718269074?s=20

[Rakesh]

News doing rounds on twitter, kaveri with modified afterburner put out 81kn. Can we hope it to power Tejas mk1a anytime soon?
https://x.com/HemanNamo/status/2025902791718269074?s=20

We are inching there, slowly but surely. Very positive developments and staying hopeful.

As for powering Tejas Mk1A, most certainly...but will realistically happen at a future MLU (Mid Life Upgrade). While the engine has achieved 81kN of wet thrust, there is a lot more testing that needs to be done at a HATF and on a FTB, neither of which are with us now. Both of those will come in due course, but F404 is the only game in town at the moment.

The Tejas ecosystem has been built around the F404 and it will remain so, for the foreseeable future. IMVHO, the goal should be to exceed the 84kN wet thrust of the F404....as the wet thrust gets de-rated operating in India's varied climate. maitya-ji can articulate in greater detail on this topic and hopefully he will chime in...if he sees this post.

But exceeding the wet thrust of the F404 is crucial, as future upgrades (better radar, sensors and weapons) will require additional power than what the F404 currently produces. The short term goal is to start production of the KDE to mount onto the Ghatak UCAV. The long term goal (i.e. MLU) should be an after-burning variant of the Kaveri onto a "future" Tejas Mk1B.

[chaitanya]

Can some ghataks be modified to become drone-based flying test beds? If so, that would probably be the fastest and most cost-effective way to get an FTB at this rate

[bala]

While the engine has achieved 81kN of wet thrust
the goal should be to exceed the 84kN wet thrust of the F404

81 KN for tejas is more than sufficient. Most aircrafts don't need the high thrust regime, it is only used for fast escape but empties the fuel quickly. Aircrafts, like cars, cruise at around 1/2 power or less most of the times.

Getting Kaveri into Tejas should be the top priority for India. This implies getting over the test curve quickly and certification of the engine. Once it proves to be reliable then Tejas mid-life refit should switch to Kaveri.

Things like Ghatak etc are good as a test bed for the engine. The MoD babus should be hawk-eyed about the testing for Kaveri and smooth the path as deemed.

[vera_k]

Apologies for being a wet blanket, but this "news" does not compute without more information.

The engine was reported to be 135kg overweight in 2008.
Since then, a composite bypass duct was implemented, which should reduce weight by 20-25kg.
A new AFADEC was designed, which should reduce weight further.

And now this post says new materials were used.

All these improvements together should have brought the engine closer to weight of the F404IN.

What explains it being 130kg overweight then?

FWIW, another post from the same handle with a graphic saying 200kg weight reduction is needed

Roadmap

[dinesh_kimar]

Apologies for being a wet blanket, but this "news" does not compute without more information.
Roadmap

Yes , news indeed talks abt composite duct, etc. which saved weight.
However, new fan to reduce afterburner screech / distortion was reported.
New materials for hot sections , with resultant changes (DM4 blade?).
New afterburner from Brahmos Aerospace.
KADECU unit was upgraded
New beefed up starter unit -GTSU 110 MK-II
Localised AMAGB gearbox PTO shaft and localised bearings from HAL.

All these new stuff might have added their own weight penalties to the Kaveri engine. I believe such consequences are not unknown in Aero Engine development.

As a part of speculation from a layman, I would also venture to add that GTREs consultant SNECMA is not the same league as GE and Rolls Royce ( Largest engine is 95 KN M-53 on Mirage 2000, GE has 512 KN on GE-90, RR has 430 KN on Trent).

In component design, their fallback approach might be to increase Factor of Safety/ Material dimensions to deal with higher stresses ( various thermal and structural).

RR and GE might go along with new alloys, quintple laser holes, less Factor of safety for required life as specified by MTBO,etc.

All these changes might have their own weight penalty.

[Aditya_V]

Any idea why Kaveri, KDE are not being considered for HLFT 42 programme?

Shortage in THrust weight should matter lesser here given these are trainers, and meant to be cheaper and also to be considered for export where we would not need US approval