Kaveri & Aero-Engine: News & Discussion

[Rakesh]

Pardon me for asking again, not clear.

The F-414 INS6 has 98 kN max.

AMCA supposedly needs 110 kN.

One option is to lean on the F-414 EPE avatar, which tops around 117 kN.

Any idea what the game plan is? How is the Indian partner going to cover this deficit?

The plan has been laid out by the stakeholders for a good length of time now. What is really not clear?

A total of seven AMCA squadrons are to be inducted. The first two AMCA squadrons will have the GE F414 INS6 turbofan. This is the Mk1 variant. The next batch of five AMCA squadrons (Mk2 variant) are to have an indigenous turbofan (minimum 110kN wet thrust along with supercruise in dry thrust). For this JV, bids are being evaluated by a team led by Dr Kota Harinarayana. The EPE is a non-starter, as the IAF is insisting on an locally developed turbofan.

The three contenders are General Electric, Rolls Royce and Safran. This contract of F414 screwdrivergiri is not tied into the JV turbofan program. Nothing can be ascertained for certain (i.e. game plan), till the evaluation team chooses the partner it believes that is best suited for India to reach her desired objective. In the absence of this, we will be shooting darts in the dark. Best avoided.

[NRao]

By game plan, I meant not just what techs may be negotiated but also a time frame.

So, what potential techs: from https://www.youtube.com/watch?v=4Gek8B7 ... NewsGlobal (two days ago){Arun Singh, former ambassador to Washington}:

in the fact sheet that had been put
3:03
out by the White House after that
3:04
meeting in January there was a specific
3:07
reference that they would try to
3:09
expedite U.S consideration of The
3:12
Proposal form G for transfer of
3:15
technology and production of India of
3:17
jet engine technology something that the
3:19
US had not done before and there is the
3:22
odd (I heard it as "hot") section of the jet engine which
3:24
technology U.S has not transferred to
3:26
anyone except to the UK yeah so that
3:30
works out it would be something new so
3:31
now this is being discussed uh so there
3:34
is a new context there is a new
3:36
framework enabling technology transfers
3:38
uh the Indian foreign secretary in fact

And, from what I can gather the IAF expects this new engine to come online in 2035. So, 12 years from today. A completely new engine, tested and all. In which Indian engineers were able to gain some knowledge and capabilities.

My mention of the EPE was to use (12/15-year-old) techs as a foundation for this effort.

IMO both France and the UK are in this to get Indian money to advance their own technologies - which is OK, that is what they do, it is a business deal.

[Vips]

A total of seven AMCA squadrons are to be inducted. The first two AMCA squadrons will have the GE F414 INS6 turbofan. This is the Mk1 variant. The next batch of five AMCA squadrons (Mk2 variant) are to have an indigenous turbofan (minimum 110kN wet thrust along with supercruise in dry thrust). For this JV, bids are being evaluated by a team led by Dr Kota Harinarayana. The EPE is a non-starter, as the IAF is insisting on an locally developed turbofan.

The three contenders are General Electric, Rolls Royce and Safran. This contract of F414 screwdrivergiri is not tied into the JV turbofan program. Nothing can be ascertained for certain (i.e. game plan), till the evaluation team chooses the partner it believes that is best suited for India to reach her desired objective. In the absence of this, we will be shooting darts in the dark. Best avoided.

We will have to rule out Rolls Royce as a 5 year ban will kick-in due to the investigation about the kickbacks it gave for getting the engine contract. RR was getting very aggressive in trying to win the deal, it was proposing a clean sheet design, was giving maximum TOT and even IPR(Intellectual Property Right) for the joint development of the new engine.

Safran true to the French play book was asking for a lot of money and foisting a lot of conditions, Using the M88 Core as the base for a new engine, while agreeing only to partial IPR so they have lesser chances of getting selected.

The RR kickback news leak has broken out at a very convenient time for the competitors.

So that only leaves one company in the field. Make no mistake if Uncle Sam wants this deal the competitors do not stand any chance.

[ramana]

UK is playing fast and loose with RR's offer. They want more than what they initially stated.
Looks like govt wants to play Shylock.
Same problem since the 1950s wrt jet engines and the UK.
Enqyoob can correct me but a core can deliver only so much.
It's a function of diameter, length (stages), and Temperature.
M-88 max can deliver 115KN.
And IAF keeps demanding Mk2 into a bullock cart and DRDO obliges.

[Rakesh]

By game plan, I meant not just what techs may be negotiated but also a time frame.

The 110kN turbofan program (and the AMCA program itself) is so far off in the future, that what we know today will *NOT* be the actual product. If we had a crystal ball to predict the future, we could see what the time frame is...but we don't have one.

They have not even chosen the foreign partner yet for this JV. So even the stakeholders in India are unsure of what the final product will look like. They have an idea that has been conveyed to the foreign partners, but nothing is concrete. Until the foreign partner is chosen, we will be in full speculation mode or as I mentioned earlier, shooting darts in the dark. Rarely does anything in military programs arrive on time and on budget. And in the Indian scenario, that always holds true. No certified 110kN turbofan is coming in 2035. Even AMCA will not be ready in 2035, even though she may have flown by that date.

So, what potential techs: from https://www.youtube.com/watch?v=4Gek8B7 ... NewsGlobal (two days ago){Arun Singh, former ambassador to Washington}:

The above transcript states, "...there is the hot section of the jet engine which technology U.S has not transferred to anyone except to the UK. Yeah so that works out it would be something new, so now this is being discussed uh so there is a new context there is a new framework enabling technology transfers..."

The key point in the above is if the negotiations actually work out in India's favour. From the foreign partner's perspective (GE, Rolls Royce or Safran), they are well aware that they are holding all the cards in the deck. There is zero leverage that India possesses in these negotiations. Do not mistake a government's willingness to transfer a production line will actually translate to the corporation (GE, Rolls Royce or Safran) actually wanting to meet that government's expectations. Governments come and go, corporations stay forever.

It is certain that India will not get the hot section. It is NOT an issue about money. It makes zero business sense for GE to transfer such technology to India. When Arun Singh mentions about US transferring such technology to the UK, please understand that this is a relationship that has a very solid foundation over decades, if not centuries. The industrial output of the UK is also so miniscule (when compared to the US), that they are no threat to GE or P&W. Rolls Royce complements them, rather than competing with them.

If GTRE could actually produce a turbofan along the lines of the technological wizardry that is the GE F414-INS6, it is game over for GE. What costs GE to produce a single F414-INS6, India could very well likely do it for cheaper with a local alternative. What really is the positive for GE (or any corporation) to introduce another competitor into a market in which they have a near monopoly?

We will do screwdrivergiri of the GE F414-INS6, just like we are doing with the AL-31FP for the Su-30MKI or the RD-33 for the MiG-29. If we are turning the screw from left to right on the Russian engines, we will be turning the screw from right to left on the American ones. We can sugar coat it and state otherwise, but this is the reality. HAL has also been producing Western turbofans as well ---> the RR Turbomeca Adour Mk811 turbofan for the Jaguar fleet and I believe also the Adour Mk951 for the BAe Hawk. If we learnt anything of value (like how HAL loves to claim that they are manufacturing the AL-31FP turbofan from the raw material stage), what is the point of having a competition to select a foreign partner for a JV for a 110kN turbofan?

And even if GE provides said ToT, the infrastructure to absorb such technology simply does not exist in the country. We don't even have a flying test bed in the country and we want a 110kN turbofan to be ready by 2035! We will have to build a whole new set of infrastructure to successfully absorb the level of technology present on the GE F414-INS6. License production of this particular turbofan is a better bet and a more successful endeavor for the bureaucracy to publish in their annual achievement brochure. Minimum Investment for Maximum Exposure is the name of the game in the power halls of New Delhi. And no one will be the wiser.

Tejas can be put into a MoD achievement brochure. It is a "visual" deliverable that everyone can see. Who thinks about the F404 turbofan that is powering that particular Tejas? Not a single soul. After 70 years of being mentally conditioned to think only in five year plans (1947 - 2017), our babus are simply not capable of thinking in terms of investing money into a project, over multiple decades, with zero tangible *VISUAL* result. The babus overseeing the development of the AMCA turbofan program today, will not be the same set of babus that will be overseeing it in 2035. And then we have political agendas (and vendettas) that will be used to undermine programs. And there will be an equal (negative) push from the services who have their own axe to grind.

And, from what I can gather the IAF expects this new engine to come online in 2035. So, 12 years from today. A completely new engine, tested and all. In which Indian engineers were able to gain some knowledge and capabilities.

When it comes to program management, I stopped believing - a long time ago - anything that the IAF says. If one wants to learn how to fail in program management, the services (especially the army and the IAF) are the best candidates for that. Hop, Skip and Jump from one utopia to another. Crawl, Walk and Run is a concept that is anathema to the services.

No AMCA turbofan is coming in 2035, with the present attitude and outlook. They will license produce the F414-INS6 till kingdom come. And whenever AMCA gets ready to take to the skies (metaphorically speaking), they will then put out another contest for a JV with a foreign OEM, for a more powerful turbofan than the F414-INS6. And then rinse and repeat. This is the stage we are at now.

My mention of the EPE was to use (12/15-year-old) techs as a foundation for this effort.

Reword the above to state the following ---> EPE will be used as the foundation for the next screwdrivergiri effort. And this is despite the IAF claim that they want a locally developed turbofan. I am not attempting to be pessimistic for the sake of, but as I said earlier...we cannot even purchase some used B747s or A340s to be used as FTBs. Let them actually take that step first and then we can have a serious discussion. Maitya-ji can certainly some provide some more basic foundational investments. But till this occurs, lets drop the pretense and do screwdrivergiri. That is the only thing we want to do.

IMO both France and the UK are in this to get Indian money to advance their own technologies - which is OK, that is what they do, it is a business deal.

The US is no different either. Engine manufacturers are not countries. What a government wants as a foreign policy objective, will not translate into what a corporation has for its future business outlook. Corporations are in the game solely for profit. It is the foundation of their existence.

[hgupta]

The US is no different either. Engine manufacturers are not countries. What a government wants as a foreign policy objective, will not translate into what a corporation has for its future business outlook. Corporations are in the game solely for profit. It is the foundation of their existence.

If that was the case, then the corporations would be seeking the highest profit margins and that wouldn't necessarily be engines but something else. Obviously it takes another to tango. So I would modify your statement with a caveat: Profit combined with seeking to achieve national objectives & goals.

[A Deshmukh]

Kaveri has to compete with 2-3 other engines that are decades ahead in technology.

We do not have the infrastructure - flying test beds, wind tunnels, etc.

Imvho, What we need to do is build a unmanned flying test bed around the existing version of the engine.
Ghatak/SWIFT is in the works, but that will have its own challenges also - stealth, autonomous flying regimes, weapons integration. development of all other features will take its own time.

The cheap flying test bed should take the Kaveri up in the air, go to different speeds at different heights and land (and let it crash a few times). without bothering about stealth, weapons, etc. It can be an ugly aircraft.

[chetak]

The US is no different either. Engine manufacturers are not countries. What a government wants as a foreign policy objective, will not translate into what a corporation has for its future business outlook. Corporations are in the game solely for profit. It is the foundation of their existence.

If that was the case, then the corporations would be seeking the highest profit margins and that wouldn't necessarily be engines but something else. Obviously it takes another to tango. So I would modify your statement with a caveat: Profit combined with seeking to achieve national objectives & goals.

why would they transfer such technology and willingly (and also foolishly) create another competitor for themselves

ISRO has already entered the space launch market with cheaper solutions and costs.

For what it's worth, we have entered the weapons export market, and going forward, this business is only going to increase.

So the goras have every reason not to trust us to disrupt their markets

Reactor wise, the progress shown by India is remarkable. India is helping out the beedis and SL in building their nuclear reactor facilities and also training their guys at koodankulam

But as far as the engine tech goes, it affects India very significantly, both in the Naval, and aerospace sectors.

why would they transfer such technology and willingly (and also foolishly) create another competitor for themselves and also ruin a ready market that they could exploit for some decades to come, especially at the fancy prices that we are paying out.

[NRao]

I am on vacation till end of June, I do not have a laptop, and very, very rare connectivity for my cell.

A few comments.

Chetak ji,

Jet engines, space launch, mil exports, क्या खिचड़ी बनाई आप ने.

Bhai saheb, giving every aspect of making every section of a "jet" engine will only give you just that - how to make that one engine. Nothing more. With that knowledge there is zero guarantee that you can even improve that engine by 1%. You might do it. But, that would pure मटका - luck. If that was the goal, good. But, you will never know if that was the cheapest, most efficient, physically strongest, ....... 1% better engine. For you to know all that you need huge funds - only because the problem is arguably the most complex.

My understanding of what the ambassador said is that the US and GE are willing to part with the R&D data for the hot section and the processes to make that section. Now, even with this it will take a decade or so to improve a F-414 from 98 kN to the desired 110 kN. AND, they could still fail!!! Because we have no idea what Indians are looking for in an 110 kN engine (besides the thrust).

So, even if this effort does succeed there is just no way India becomes a power player in the jet engine space. All it means is that India will be independent as far as a 110 kN engine, with all associated restrictions (TW ratio, etc). India will not be in a position to design, say, a 125 kN engine. For that billions for decades just to gather data.

And, rocket engines are a totally different beast.

[Rakesh]

Thank you Chetak-ji for replying to hgupta. I could not have said it any better.

My understanding of what the ambassador said is that the US and GE are willing to part with the R&D data for the hot section and the processes to make that section.

The Ambassador has said nothing of that sort in the link you posted. You are reading way too much into what he said.

GE will not part with the R&D for the hot section of the GE F414-INS6. The media is gullible and will portray this as real ToT. And unfortunately there are people who will buy that cock-and-bull story as gospel truth.

[chetak]

I am on vacation till end of June, I do not have a laptop, and very, very rare connectivity for my cell.

A few comments.

Chetak ji,

Jet engines, space launch, mil exports, क्या खिचड़ी बनाई आप ने.

Bhai saheb, giving every aspect of making every section of a "jet" engine will only give you just that - how to make that one engine. Nothing more. With that knowledge there is zero guarantee that you can even improve that engine by 1%. You might do it. But, that would pure मटका - luck. If that was the goal, good. But, you will never know if that was the cheapest, most efficient, physically strongest, ....... 1% better engine. For you to know all that you need huge funds - only because the problem is arguably the most complex.

My understanding of what the ambassador said is that the US and GE are willing to part with the R&D data for the hot section and the processes to make that section. Now, even with this it will take a decade or so to improve a F-414 from 98 kN to the desired 110 kN. AND, they could still fail!!! Because we have no idea what Indians are looking for in an 110 kN engine (besides the thrust).

So, even if this effort does succeed there is just no way India becomes a power player in the jet engine space. All it means is that India will be independent as far as a 110 kN engine, with all associated restrictions (TW ratio, etc). India will not be in a position to design, say, a 125 kN engine. For that billions for decades just to gather data.

And, rocket engines are a totally different beast.

NRao saar,

the amrikis ruined Nambi Narayanan's life for the rocket engine and sabotaged ISRO's efforts to develop the cryogenic engine just because they did not want India competing in the commercial payload launching business.

And look where we are at today, we are competing in the commercial payload launching business, just like they feared.

BTW, all those Indians employed at NASA aren't there for janitorial services, no...

[Rakesh]

Great example Chetak-ji.

[NRao]

chetak ji,

Ah. OK, that angle. But then, as I said a few months back, Modi must not venture outside India. And, he is expected to teach Devanagri script to the US Congress I am told. But then .......

However, my response still stands. Just because India was able to overcome cryogenic engines for rockets, they are nowhere close to tackling an advanced jet engine. Not because of a lack of brain power, but due to risk averseness and total lack of funds. Recall India had to build all test facilities for rockets, even high alt ones. Got it done because it was under the PMO. There are no test facilities for jet engines in India and I do not see any efforts to build any.

Rakesh ji,

The Indian request for hot section R&D data was denied in the DTTI process. So, the new effort has to overcome that sticky point IF the US/GE want to move forward. No R&D data, absolutely no start of a new development effort. India has no funds to generate that data, nor the time.

My recollection is that the EPE and EDE took a cool 10 years. And, that was with 100%visibility into all R&D data at GE!!

It will take India multiple decades to collect that data, if Indiawere to go alone. There can never be an engine for the AMCA by 2035. Not happening without a base trusted R&D data matrix. Cannot say it has to be f414 or f404 or fxxx. But, it needs a TRUSTED, replicable data matrix.

Besides that Doval, a few weeks ago, in DC, issued a fatwa. Essentially, no more talks, here is what we want, and if you claim you will help then produce.

BTW, what the ambassador said is in a Jan 2023 readout from IIRC the White House.

And, finally, CIVILIAN granted. But, the GE9X engines (for AI ordered Boeing 777) are designed in India. 70% of the team is in B'luru. Civilian engine for sure. The same team is designing a GE + Safran engine in India!!!

Take care folks.

[maitya]

<snip>
Enqyoob can correct me but a core can deliver only so much.
It's a function of diameter, length (stages), and Temperature.
<snip>

Ofcourse the grand-mullah Enqyoobdin Gas-turbini (PissBUH), knows the most, but normally yes, there're are limits to how much a core can be tweaked to deliver more and more thrust levels - max 15-20%, but there also, in most high-end cases, it is almost as good as a new design.

GE F404 to F414 is a prime example of it, actually - on paper, it'll appear that the "subsystems" like HPT/HPC/Combustor etc have been "upgraded" or simply replaced, but in reality it's more or less a new engine.
Of course, for a powerhouse like GE, with decades of experience (and absolutely the very best infra) would have meant they could pull it off within a decade. For a novice country like India etc, it will take much much more (both time and budget).

And to elaborate about your point wrt "It's a function of diameter, length (stages), and Temperature", pls consider the following 5-part series:
(Gentle Rakshaks, a humble request - pls allow me to post all the 5 parts in a sequence, pls try and not interrupt the flow - we will go back to general programming once I have completed posting all the 5 parts)

[Rakesh]

NRao: no -ji for me please. I will reply to your post in a bit.

(Gentle Rakshaks, a humble request - pls allow me to post all the 5 parts in a sequence, pls try and not interrupt the flow - we will go back to general programming once I have completed posting all the 5 parts)

maitya-ji, go right ahead and start posting all five parts. I will monitor the thread going forward, so you can post in sequence.

If anyone does interrupt that sequence, I will delete their posts and ask them to hold off, till you complete your sequence. Any posts of mine that disrupts your sequence, I will remove that as well. Go right ahead and start. Thank You.

[maitya]

[Part-1: Introduction]
(It'd have been much easier if I'd known how to create tree structure etc in the forum software and depict the following pictorially - but no joy there)

There're no hard-and-fast rule, but generally for a low-BPR military turbofan, approx 70-75% of max dry-thrust would normally come from the Core/Gas-generator - rest 25-30% from the LPT/FAN combo.

Now if the Core/Gas-generator is to be targetted for any thrust improvements then:
In the thrust equation, it is the product of mass-flowrate thru core and diff of gas vel (betw entry and exit). So, if the thrust must be increased then, it can be done via,
1) increasing the mass-flow-rate - but that itself can be done by either,
1a) increasing the volume of mass-flow-thru-core - this is via dimension change etc of the inlet, which ofcourse, is the least preferred method. Just increasing the mass flow without enhancing the OPR and TeT, would immediately result in lower Thermal efficiency - which means higher SFC values, and no user/AF would want a gas guzzler.
or
1b) increasing the velocity of the gas mass - increasing the vel can be achieved by increasing Pressure Ratio achieved by the HPC system.

But before we delve more into these aspects, do note however the following:
1) Increasing SPR of the HPC stages, the stagnation pressure (and thus the gas-temp) of the airflow will rise across the HPC stages.
The reason why typically the blades of last stages of the HPC are non-titanium-based (and normally Ni-superalloy based) are exactly because of this.
The ambient temp in the last HPC stages would then typically go up to around 700-800odd deg C, where-in the Ti blades would start failing (beyond 500 deg C) - so Ni based superalloys are used instead.
But then again, Ni-superalloys are few orders higher in density (compared to Ti, ~2-2.5 times), so the weight-creep happens.
That's the reason the first stages (the larger ones) are typically manufactured from Ti, while the very last stage(s), which are the smaller/smallest ones, are from Ni based superalloys. Nice compromise wrt the weight and cost of the overall HPC.

2) Also, there's a limit to which the HPC SPRs can be increased - due to phenomenon called choking (sometimes referred to as back flow).
Depending upon the aerodynamic features of a HPC like blade profiles, variable geometry components, bleed valves etc, the max mass-flow rate through HPC stages are designed beforehand.
All these aspects results in determining the HPC efficiency, and crossing those limits would essentially mean compromising the HPC efficiency itself.

[maitya]

[Part-2: HPC PR Improvement]
Anyway, coming back to the topic, increasing the Pressure Ratio of HPC is achieved by either,
1b1) simply adding an HPC stage - of course, that'll have weight penalties and is basically a complete redesign of the core
or
1b2) achieving higher RPM of the HPC stages (and thus enhancing the SPR figures)
or
1b3) by increasing the efficiency of the aerodynamic design (and thus the efficiency) of the HPC stages.

Now, let's for a minute, try and understand 1b2 above - i.e. how to improve Pressure Ratio of HPC by achieving higher RPM of the HPC stages.

This is achieved by increasing the work extracted by HPT, which in turn is achieved by either,
1b2a) increasing the TeT of the HPT - this is where the holy grail of intermix of some absolutely cutting-edge metallurgical tech, multi-level of manufacturing tech complexity etc comes into picture.
e.g. Higher gen SC blades, TBC Coating, air cooling of the blades (both internal (convectional and impingement) cooling and external (film/transpiration) cooling), Laser or EDM drilling etc etc etc are just some of such technological capability enhancements required.

For further glimpse on this aspect, you may want to refer to this old post of mine - and if you are interested in knowing about various gens of SCBs etc, you may want to refer to this very old post of mine.

Do note again: Simply graduating from 3-4th gen DS casted blades (e.g. DMD4) allowing ~1050deg C ambient temp operating capability, to, say 4th Gen SC casted blades (e.g DMS4), would not automatically allow the overall TeT to increase by 175-200 deg C (i.e. if the intent is to graduate from 1455 deg C TeT to the uber 1625deg C TeT regimes).

I've written multiple posts on this earlier and wouldn't repeat the same here again.
But the summary is, under practical operating condition, which results in turbofan ingesting dust particles consisting of calcium-magnesium-alumino-silicates (CMAS), the max that a 7-8YSZ TBC coating can withstand is limited to ~1150-1200deg C.
And the only way to circumvent this conundrum is the bilayer TBC application - e.g. LZ-YZ bilayer TBC, which under similar CMAS attack, would allow the operating temp to approx 1400-1450deg C.

Also what has never got asked to the GTRE folks are:
If M88-2 can achieve 1580deg C TeT using MC-NG (another 4 Gen Superalloy for SC application), why can't/didn't GTRE try the same with DMS4 (same Gen and very similar raw temp characteristics)?
And if the answer is there was no need wrt K9 etc, then query can be why not now via the funded dry Kaveri variant?
(Do note both current Kaveri DS blades and M88-2 uses the similar 8YSZ TBC coating - so it's more of a question wrt slightly improved blade-surface cooling tech etc)

And if the so-called Snecma JV goes thru for the 120KN engine etc (for AMCA), I'm almost sure the same Superalloy based SC casting tech would be used as well.
And if we were ready, we could have insisted the core be via this indigenous route etc etc etc.
The M88-4 program (which never got off) IIRC envisaged using bilayer TBC etc for the same base superalloy and SC tech for the HPT blades. I think, via this JV route, they will try and get the M88-4 program going (I mean funded by India's money).

or
1b2b) enhancing the efficiency of the HPT itself - which is itself achieved via either,
1b2b1) reducing the secondary losses in the HPC setup. And then there are other aspects like improving the end-wall contouring (to prevent secondary losses, better distribution of Mach number across blade surface).
However, there's only so much of headroom available, if we are talking of Kaveri type of well-designed turbomachinery.

or
1b2b2) bring in path-breaking stuff like contra-rotating rotors (HPT and LPT) etc - Do note there are two ways of achieving this as well:

1b2b2a) one via just introducing the contra-rotating rotors without eliminating the stators - something the GTRE folks experimented around 2016-20 timeframe etc, and IIRC (not sure, need to check in published results etc) achieved approx 2% of efficiency gain.
However, this route will not provide additional benefits like reduced "turbine complex" weight etc, which is also, in the scheme of all these incremental advancements/improvements, a significant aspect.

or
1b2b2b) introducing the contra-rotating rotors and eliminating the stators as well. Here reduced turbine weight related gains (additional torque via additional work extraction etc) also contribute.

[maitya]

[Part-3: HPC PR Improvement via Aerodynamic route]
Now let's come back to pt 1b3 - i.e. increasing the Pressure Ratio of HPC by increasing its efficiency via improvements to aerodynamic design of the HPC stages.
Now this can be done, via multiple ways, but none of them are easy and none, for a well-designed turbofan, will provide any quantum jump etc to the OPR level etc.

1b3a) One way is via going to wide chord blade design and may be even to multi-circular arc profile compressor blade design. Which would mean graduating to tip Mach numbers trending towards 1.6M, allowing achieving SPRs of around 2.0 (5th gen stuff a la F119 etc).
The details of these can be found here, in the sticky thread.

1b3b) Other slightly conservative approach would be to reduce the weight of the HPC complex via mastering blisk (30% weight reduction) or even bling (70% weight reduction) design.
Do note the HPC disks would still need to be capable enough to handle the centrifugal forces of the rotating HPC blades (1.6M etc) - so all these bling design etc needs lighter HPC blade weight as well.

1b3c) Another even more conservative approach is to go newer HPC blade materials like Titanium Aluminide etc.
The Titanium-Aluminide intermetallic (especially the γ-TiAl-with Nb), is almost half the weight (density of 3.9-4.2gm/cc, quite close to that of pure Ti at 4.5gm/cc) of that of Ni-Superalloys.
But it has excellent high temp properties (creep and oxidation resistance - maxing at around 800-900deg C, compared to ~500 odd deg C of pure Ti)) and is thus a very good replacement of the Ni Superalloy based blades of the heavy last stages of the HPC.

However, γ-TiAl is notoriously difficult to use in complex-geometry manufacturing etc - that's why the interest was quite lukewarm until recently, though this is atleast 2.5-3 decade old tech.
But recently, the advent of its production via additive manufacturing, which sidesteps these casting and brittleness related mfg difficulties, has again rekindled interest in it. So much so, GE have used γ-TiAl based LPT blades in their GenX engine program.

One point that is noteworthy here, in high BPR applications of Civilian Turbofan, LPT (and the Fan) are far more critical aspects and thus they garner hugely disproportionate amount of attention (and funding) by all major engine houses.

Do note that, best would be to somehow leapfrog and achieve CMC based HPC stages - but that requires an obscene amount of funding, spanning decades of focused and unrelenting R&D.
The comparable density figures are:
CMC - 2.1gm/cm3, y-TiAl - 3.9-4.2gm/cm3, pure Ti - 4.5gm/cm3, Ni Superalloy - 8.5+ gm/cm3

[maitya]

[Part-4: The LPT/FAN route]
So anyway, back to the topic: what is the alternative wrt increasing thrust levels of a well-designed low BPR turbofan.

Well, pls refer to the 1st line of the post i.e. generally for a low-BPR military turbofan, approx 70-75% of max dry-thrust would normally come from the Core/Gas-generator - rest 25-30% from the LPT/FAN combo.
Now if tinkering with Core/Gas-generator is ruled out, how about targetting the "rest 25-30% from LPT/FAN combo".
So basically, by increasing the proportion of the dry thrust produced from the Fan while keeping the core as is.

This can be achieved by increasing the mass-flow-rate thru the Fan but, at the same time, avoiding the increased mass-flow to enter the core - so bypass the increased mass-flow.
i.e. since the Core is not being changed, so the additional mass flow is meant solely for bypass - thus an increase of the BPR would be required.

1) One way of going about this is via increasing the efficiency of the LPT, so as to increase the FAN rpmetc - and increasing the FAN rpm would definitely increase the Fan PR and also the mass-flow.

And one way of increasing efficiency of the LPT is via weight reduction - so better/lighter material for the LPT blades that can withstand the moderately high TeT levels (of LPT) ~ 800-1050 deg C.
Here again also, lighter the LPT blades, more option of using Bling etc so that disc weight itself can be reduced drastically (as much as by 70% wrt conventional "solid" discs).
Of course, if CMC based blade manufacturing tech has been mastered, nothing like it (refer to the density diff between these materials) - but even intermetallic like y-TiAl would also do.

Betw nobody bothered to ask a simple question to GTRE, all these years:
How come F404 achieves 13200rpm for the LPC while Kaveri languishes at 10312rpm - is there a deficiency wrt the Kaveri LPT itself. After all F404 doesn't use any of these exotic CMC/intermetallics etc for it's LPT, it plain vanilla Ni-superalloy.

A word of caution here: the temp profiles of the LPT may not need a SC casted Ni-superalloy, a equiaxed casted one would do (like Kaveri) - but all 3 big brothers F414/M88-2/EJ2000 uses SC casted solutions. Because unlike the HPT, a solid SC casted blades would be good enough to handle the temp involved, without getting into internal and external convectional-cooling solutions.

2) Another method would be increase the efficiency of the LPC/Fan itself - this is bit tricky, as though Fan blade geometry etc can modified and slightly higher mass-flow etc can be achieved, there's normally not much of head-room available for a well designed turbofan.
Unless of course, one goes the CFRP route (a la GE in their GE9x program) for LPC - uses Ti inserts in their leading edges etc etc.

Generally a combination of both 1 and 2 are employed.

There are innumerable examples, and the clue is to look-out for 0.3-0.4:1 etc type of BPR values.
The two that I could lay my hands on currently are:
1) M88-2 (73KN) to M88-3 (93KN)

The M88-3 features a new LP compressor with higher mass flow (from 65kg/s in the -2 to 73.4kg/s).

2) EJ2000 - future variant (Stage-2)

More interestingly perhaps is Rolls-Royce and EuroJet's plan to increase the output 30% above the baseline specification as a Stage-2 modification. Such an upgrade will require more substantial plantwide changes including a new LP compressor and turbine and an improvement in the total pressure ratio. These upgrades would yield a new dry thrust of around 78kN (or 17,500lbf) with a reheated output of around 120kN (or 27,000lbf)

[maitya]

[Part-5: Epilogue]
I think I have written enough - and didn't even get into a few other aspects like Combustor efficiency, NGVs etc.
Summary of course is, it's very difficult, costly and time-consuming effort, to just take a core of an already-designed turbofan and trying to tinker it to produce generational level thrust enhancements (T/W ratio etc).

Of course, some level of increase, say about 15-20% can still be achieved, but not sure how much of it's actually worth it, if a quantum jump in thrust levels are being talked about.
i.e. taking a baseline K9 (at 51KN/73KN) and then trying to graduating to first say 56-58KN/90KN (K10), and then to 65KN/98KN (K11) without changing too much on the dimensional aspects, but getting to 75+ KN/120KN etc stuff is a completely different ball-game.

Even in the graduation to 65KN/98KN (K11) etc, it may actually be more beneficial to go for a clean-sheet design, but for that to happen all the above-mentioned enabler technologies needs mastering first, at at a mass-manufacturing level.

And, for 75+KN/120+ KN stuff, I think where all these collaborative turbofan development with an established foreign engine house etc, is aiming at to somehow "get" 5th Gen military turbofan design and manufacturing knowhow via a joint-design-and-development program with a foreign OEM.
All whilst, we ourselves have not "proven" to the world, wrt our capabilities wrt mastery over 4th gen turbofan design and production. Kaveri, even with its slightly overweight-and-slightly-lower-wet thrust, would have exactly done that had it been flown over 4-5 years etc.

The talk of getting Kaveri to fly has been there from 2010-11 onwards ... but no funding, so nothing much achieved, instead dry-Kaveri variant etc is the current focus area.
But then again, expecting Baboons and politicos, expert that they are wrt sloganeering/stalling/triplet-signing of docs etc, to even appreciate such facts, is well ...

My prediction wrt this AMCA turbofan joint-development stuff, is what Rakeshji has just predicted in the recent post above, we will continue to do TOAST type bania-giri contract negotiations and confine ourselves for next 2 decades, to whatever we have been doing so far i.e. SKD/CKD Assembly and limited testing.
No worthwhile turbofan design and manufacturing tech is going to come out of it.

Unless of course, we generously fund (and expedite) a K10 program and then K11 program via indigenous development route, gradually developing and incorporating Gen 5 turbofan systems/concepts.
Only then one day, maybe we will have an indigenous capability of turbofan design, development and manufacturing – until then this ToAsT tamasha to continue, I guess.

[Pratyush]

Maitya,

1) In one of your posts above you have mentioned the difference between the RPM of both the 404 and the Kaveri.

2) one of the you tube defence channels has reported that GTRE has approached the MOD for approval for work on a 55 kn dry thrust kaveri. On the basis of the work done on the current kaveri by it.

Can the gap between the two levels of dry thrust be met by having higher RPM on Kaveri?

If yes.

Do the existing materials used in the current iteration permit and increase in the RPM without any issues?

Or the whole development excercise has to be repeated by the GTRE for the higher levels of dry thrust?

[VishnuS]

[Part-4: The LPT/FAN route]
So anyway, back to the topic: what is the alternative wrt increasing thrust levels of a well-designed low BPR turbofan.
<snip>
2) EJ2000 - future variant (Stage-2)

Bhai, I absolutely know nothing about HPT and TBH, I could hardly grasp except it. That being said, I have a question regarding LPT, It would be great if you could answer it.

During 2022 DefExpo conversation with one of the directors of HTFE 25, he said 3D printed metal parts are lighter than regular parts, some are 20 to 30% than standard cast.

My question is why don't we use 3D parts for LPT? or Are we using it already?

[maitya]

Maitya,

1) In one of your posts above you have mentioned the difference between the RPM of both the 404 and the Kaveri.

2) one of the you tube defence channels has reported that GTRE has approached the MOD for approval for work on a 55 kn dry thrust kaveri. On the basis of the work done on the current kaveri by it.

Can the gap between the two levels of dry thrust be met by having higher RPM on Kaveri?

If yes.

Do the existing materials used in the current iteration permit and increase in the RPM without any issues?

Or the whole development excercise has to be repeated by the GTRE for the higher levels of dry thrust?

Pratyush-ji, there I'd compared the published rpm difference between the LPT stages of F404 and Kaveri.

Now there're not enough open-source literature available wrt exact perf parameters of these, so very difficult to provide an accurate answer.
However, generically speaking, going from 50-51KN to 55KN is approx 10% growth, which should be doable via LPT-FAN improvement route.
Do note a lower LPC/FAN rpm would indicate suboptimal perf of the LPT (which drives the LPC/FAN shaft) - but, the published isentropic efficiency figures, were decent (not great) though - IIRC 87-88% with good surge margin to boot.

So basically if the LPT efficiency can be increased by 3-4% and graduate to low 90s, that should do it, IMVHO - as any increase in FAN rpm would increase the mass-flow-rate, increasing dry thrust (more on this bit, at the end*).

What is very difficult to even speculate is how would this LPT efficiency gain going to come about.
It doesn't look like it'll be via LPT weight reduction route - as, per published data, Kaveri LPT uses CMX-4 SC solid blades (I always thought it was DS casted solid blades), without any air-cooling etc.
Which is fine, as CMX-4 (3rd gen SC material) has raw temp handling properties of ~1050-1100 deg C, which is enough for most LPT applications - even, I'd wager, Equiaxed casted blades of the same/equiv material (say around 900-950 deg C) would also be enough for Kaveri LPT.

So, these blades wouldn't be too "heavy", so that they can be made lighter - making blades lighter, would mean lesser centrifugal force load for the LPT disk to contend with, which in turn allows introduction of blings (results upto 70% weight reduction) etc.
If not the blades, then the LPT disc could have been looked into - but there also it's currently PM (Powder Metallurgy) based mfg, so quite contemporary, not much scope there as well.

However, there maybe still some possibility of introducing blisks, which are known to provide ~25-30% weight reduction (enough for the modest efficiency gains, being talked about) – there were recent reports about blisks being designed and used in HTFE/HTSE (?), so quite doable.

Other option is to look at the HPT blade-design itself to make them more efficient etc - which alone, I don't think, would be a viable route for such an efficiency improvement route.
However, the LP shaft can definitely be made lighter, which would result some additional torque being transported to the LPC/FAN.

Do note however, using intermetallic (like Y-TiAl) or CMC based LPT etc, is big-huge-giant technological leap (we are nowhere close to such technological levels) - we are then looking at 20+ % thrust gain, and is thus best left for 65KN/98KN (K11) program etc.

But if LPT improvements is not going to cut-it, the only option left is to re-look at the FAN design wrt Fan blade geometry etc. GTRE have had multiple FAN designs implemented in recent years, so it's definitely within their reach - however, if that alone would be enough to provide this 10% etc thrust gain etc, wouldn't know.

Do note here, the recently unveiled high-distortion-tolerant FAN for the dry Kaveri variant wouldn't really work out here - as that had kept the mass-flow-rate exactly same as that of K9.
Of course, there the focus was wrt countering higher distortion inflow imposed by serpentine intakes, so additional IGV etc may have got introduced - for std intakes, these are not required, so another FAN design may just about work out.
(there's another post of mine wrt this aspect, in last couple of pages of this thread - you may want to refer to that)

Normally, both LPT efficiency improvement along with LPC/FAN improvements together, are generally tried for such dry thrust improvement initiatives.

------------------------
*Increasing LPC/FAN rpm would increase the mass-flow-rate, increasing dry thrust level - but since the core remains same (so mass-flow thru core also remains same), the BPR needs to be increased proportionally. So that additional mass flow is bypassed. Kaveri has 0.16:1 BPR, while F414 has 0.25:1 (so higher proportion of the overall dry thrust produced by F414 is via this LPT-FAN route).

[maitya]

[Part-4: The LPT/FAN route]
So anyway, back to the topic: what is the alternative wrt increasing thrust levels of a well-designed low BPR turbofan.
<snip>
2) EJ2000 - future variant (Stage-2)

Bhai, I absolutely know nothing about HPT and TBH, I could hardly grasp except it. That being said, I have a question regarding LPT, It would be great if you could answer it.

During 2022 DefExpo conversation with one of the directors of HTFE 25, he said 3D printed metal parts are lighter than regular parts, some are 20 to 30% than standard cast.

My question is why don't we use 3D parts for LPT? or Are we using it already?

I'd draw your attention to this old post from JayS which says HTFE-25 has In718 3D-Printed cooled blades for HPT (as well as the NGV) at a TET of 1455K (or 1182 deg C).

Now since the requirement for LPT would be around 950-1050deg C, a variant can certainly be used - but the issue is HTFE 3d-printed rotor blades are air-cooled which would mean, an uncooled variant may just fall short of the 950-1050deg C requirement. And uncooled variant for LPT would be preferred, as we wouldn't want to bite off more from the already scarce mass-flow thru the core.

Also In718 based parts are normally used for 700-750 deg C situations - the air-cooling would have taken it to 1150-1200deg C etc.
However I'm not aware if 3D printing of rotor blades would have any significant weight advantage over the traditionally casted ones, so not sure how much that would help.

Having said that, if GTRE can conjure up SLM-fabricated high metal temp materials (e.g. CM247LC), then sure that's an option to try out, I guess.

[ramana]

Maitya Why does GTRE need to go to MoD for marginal improvements? Are they asking or funding clean sheet design together 55 KN thrust capability? And a new afterburner?

[Rakesh]

The reply to the quoted post below is from Chetak-ji, in his reply to NRao. I had to remove Chetak-ji's original post, because maitya-ji had requested to post five posts in sequence without interruption from other posters. I am now reposting it on Chetak-ji's behalf.

chetak ji,

Ah. OK, that angle. But then, as I said a few months back, Modi must not venture outside India. And, he is expected to teach Devanagri script to the US Congress I am told. But then .......

However, my response still stands. Just because India was able to overcome cryogenic engines for rockets, they are nowhere close to tackling an advanced jet engine. Not because of a lack of brain power, but due to risk averseness and total lack of funds. Recall India had to build all test facilities for rockets, even high alt ones. Got it done because it was under the PMO. There are no test facilities for jet engines in India and I do not see any efforts to build any.

NRao ji,

Most people look at this from the wrong end

we have the money but not the people. And at the rate we are going we will never have the people

All foreign companies, for their India "design centers" hire our trained engineers right out from under the very noses of govt research labs and PSU's and every one of these jokers jump ship for just a few dollars more and the chance to leverage their padded CVs right into a job abroad and the hoped for green card at the end of their rainbow. The various teams are rigidly compartmentalized, isolated from one another and completely segregated by the paranoid goras to protect their IP.

You will never hear of ISI honey traps and whatsapp forwarded nude photos with these employers. That is reserved exclusively for pot bellied, bald, **** driven higher ups paid by the GoI

most of the "design" jobs done in India by gora companies are junk. They simply do not give access to sensitive data and and all the data is stored abroad, even the data for junk jobs that they do.

I have seen the jobs that are being done in India by gora aero engine companies. No hot section data is ever shown to the aam aadmi worker bees and that sort of critical work is simply not done in India because of security reasons

why do we spend so much of taxpayer money on each of the the aam aadmi worker bees when all these guys want is a green card.

and why cannot this be stopped by introducing a mandatory cooling off period of 5 years after leaving a govt job especially from research labs and PSUs or jail term or 25 lakhs fine in lieu

[Rakesh]

The Indian request for hot section R&D data was denied in the DTTI process. So, the new effort has to overcome that sticky point IF the US/GE want to move forward. No R&D data, absolutely no start of a new development effort. India has no funds to generate that data, nor the time.

My recollection is that the EPE and EDE took a cool 10 years. And, that was with 100%visibility into all R&D data at GE!!

It will take India multiple decades to collect that data, if India were to go alone. There can never be an engine for the AMCA by 2035. Not happening without a base trusted R&D data matrix. Cannot say it has to be f414 or f404 or fxxx. But, it needs a TRUSTED, replicable data matrix.

Besides that Doval, a few weeks ago, in DC, issued a fatwa. Essentially, no more talks, here is what we want, and if you claim you will help then produce.

BTW, what the ambassador said is in a Jan 2023 readout from IIRC the White House.

And, finally, CIVILIAN granted. But, the GE9X engines (for AI ordered Boeing 777) are designed in India. 70% of the team is in B'luru. Civilian engine for sure. The same team is designing a GE + Safran engine in India!!!

I believe the assembly order for the F414-INS6 is for the six Tejas Mk2 squadrons. Using a standard rule of thumb figure, six squadrons at 18 aircraft per squadron = 108 aircraft. So 108 turbofans at minimum.

Let us assume that India and the US overcome the sticking point of the hot section and India gets the entire ToT for the F414-INS6 in exchange for awarding GE a multi billion dollar contract for manufacturing 100+ F414-INS6 turbofans in India, from the raw material stage. Once India gets this tech on her hands, what is the need for India to go back to GE for the following;

* 60 - 90 TEDBF aircraft (to be powered by the GE F414-INS6). That is anywhere from 120 - 180 engines at minimum.
* 40 AMCA Mk1 aircraft (also to be powered by the GE F414-INS6). That is another 80 engines at minimum.

Because if India can xerox copy her own version of the F414-INS6 - right down to the nut and bolt - why then would India waste valuable FOREX and award GE yet another contract for 200+ to 260+ turbofans? GE knows this. The US knows this too. What really is the net positive for either of these entities to lose out on billions of dollars of business + geopolitical leverage (which has an immeasurable value)? And the same is true for Rolls Royce (UK) and Safran (France).

The engine manufacturers from these three countries have a full monopoly in low and high bypass turbofans. Why would they hand this technology over to another country, even if she is friendly and follows the rules based international order? Especially with a country like India that in every metric of value, is only rising and that too meteorically. Overtly friendly geopolitical overtures from the Western world must not be translated into us weaving fantasies of them opening the lock to their crown jewels. For the Western world, India is just the flavour of the month and to be milked for all she is worth.

This is pure assembly only, but even that is a good thing. The F414-INS6 is an excellent turbofan and will serve the Indian Air Force (and eventually even the Indian Navy) well. India does indeed operate an American fighter. It is called the Tejas. And with 40 Tejas Mk1s, 83 (and possibly another 50 more) Tejas Mk1As, 100+ Tejas Mk2s, 60 - 90 TEDBFs + X number of AMCA squadrons, that is a very significant amount of airpower all using an US origin turbofan. That kind of leverage is something countries can only dream of.

With our present attitude, India will not get her own turbofan. We don't want to invest in the fundamentals and we want a phoren partner for a 110kN turbofan. Chetak-ji put it best and I quote below...

[quote="chetak"]Instead they were waiting for गरम गरम, बना बना हलवा to be served to them on चांदी की थाली.[/quote]

[Aditya_V]

I think we have do 2 things, assemble and understand more about F404 and F414, keep the Kaveri going , buy tested aircraft to develop our own engine.

I don't think assembly is a waste, but will it mean we can skip our own R&D- No.

[sanman]

I think we have do 2 things, assemble and understand more about F404 and F414, keep the Kaveri going , buy tested aircraft to develop our own engine.

I don't think assembly is a waste, but will it mean we can skip our own R&D- No.

The Hot part of the engine, and the single-crystal turbine blades are the most crucial, and most difficult to master.
We won't be getting that tech transfer as part of this deal.

[fanne]

We have been making single crystal blade for a long time. These have been displayed at many aero india show. I guess what is lacking is a desire, backed by clear guideline, money, effort etc. I think the trust destroyed by whatever GTRE did in the past is haunting this effort. The politicos have lost trust and do not want to throw money unaccounted. These effort have no guaranteed success, that makes it more tough as money allocated may not be bringing promised result in the promised time (making the trust deficit more).
Maitiya sir has listed at least 5-6 tough tech to be mastered for the result to show up, failure of any one will doom it. All of them have to succeed, and that needs money, many teams, consistent effort (with many failures in between), time ....and then in between some smart alec makes wilfully wrong promise, it makes this all that hard.

[Pratyush]

The Indian rocket program till the mid 90s was beset with failure. Yet the political masters prevailed and kept funding the efforts. Ultimately resulting in PSLV and GSLV.

Politicians are not the problem.

[Manish_P]

...India does indeed operate an American fighter. It is called the Tejas...

wincing visibly

But well said, sir. Someone had to say it. thank you for just being plain matter-of-fact about it.

Jingos might argue it is an 'american-powered' fighter.. 40%-50%-x% can be a matter of debate. And any other semantics.
The turbofan engine is the beating heart of the modern aircraft. there is just no getting around it (except perhaps with disruptive tech bordering on sci-fi). period.

[chetak]

I think we have do 2 things, assemble and understand more about F404 and F414, keep the Kaveri going , buy tested aircraft to develop our own engine.

I don't think assembly is a waste, but will it mean we can skip our own R&D- No.

The Hot part of the engine, and the single-crystal turbine blades are the most crucial, and most difficult to master.
We won't be getting that tech transfer as part of this deal.

a few organizations in India are already doing this

but one would hesitate to say if the technology has been mastered in a general way and therefore, is capable of being adapted to various engines under development or they are doing it from ready made kits which have all the materials required and is being used merely as a technology demonstrator to develop the skill sets required.

[maitya]

Rakeshji (or any mod), is there a way you guys can rectify some typos in the last few posts (in my reply to Pratyush ji above and to the Part-2 post etc) - just wanted to make them as accurate as possible.

Pratyush-ji, there I'd compared the published rpm difference between the LPTC/FAN stages of F404 and Kaveri
...
...

[Part-2: HPC PR Improvement]
...
...
1b2b) enhancing the efficiency of the HPT itself - which is itself achieved via either,
1b2b1) reducing the secondary losses in the HPCT setup. And then there are other aspects like improving the end-wall contouring (to prevent secondary losses, better distribution of Mach number across blade surface)
...

Also delete this post, once done.

[williams]

I think we have to do 2 things, assemble and understand more about F404 and F414, keep the Kaveri going, buy tested aircraft to develop our own engine.

I don't think assembly is a waste, but will it mean we can skip our own R&D- No.

The Hot part of the engine and the single-crystal turbine blades are the most crucial, and most difficult to master.
We won't be getting that tech transfer as part of this deal.

Nothing is difficult if we put our heart into it. https://www.drdo.gov.in/technology-clus ... l/1529/170
We made some breakthroughs last year on the metallurgy front if I remember right. It is just that we need these platforms ASAP and adding a new engine development as part of that roadmap is quite risky. I think we need to do some crucial optimization work that Maitya ji mentioned here and that is going to take some time. It is not something that is out of reach from us. But we need time and investment to do that. We are far ahead in terms of test infrastructure compared to the 90s and we have the money to add more as needed. The collective Babu-Brass ecosystem is lethargic for sure but they are not stupid. They will take their sweet time and penny-pinch everything but there is an indigenous engine development in the road map for sure.

Besides Geopolitics has changed Khan will be more than happy if we drop a few Sudarshans in Pindi or Kashgar using their engines. There sure is going to be some leverage but how is that different from what we have today? We have a few of Khans' offensive systems already and we are still dependent on a dollar-dominated economy anyways. Russian platforms are slowly dying and the quality of their products is declining anyways. We just need to get these engines integrated and develop our own in the next 10 - 15 years.

[chetak]

I think we have do 2 things, assemble and understand more about F404 and F414, keep the Kaveri going , buy tested aircraft to develop our own engine.

I don't think assembly is a waste, but will it mean we can skip our own R&D- No.

The Hot part of the engine, and the single-crystal turbine blades are the most crucial, and most difficult to master.
We won't be getting that tech transfer as part of this deal.

the single-crystal turbine blades tech is already available with us and we are using it in an engine that is being made here. Don't know what percentage of indigenization has been achieved in the overall engine per se or even in the single-crystal blade itself.

Both, the engine and the single-crystal blade, seem to be working well enough.

One lab, DMRL is in the midst of a dedicated process to develop and master this tech. Modi seems to have lit a serious fire under all these guys

let's see what else can be dug out

[sanman]

the single-crystal turbine blades tech is already available with us and we are using it in an engine that is being made here. Don't know what percentage of indigenization has been achieved in the overall engine per se or even in the single-crystal blade itself.

Both, the engine and the single-crystal blade, seem to be working well enough.

One lab, DMRL is in the midst of a dedicated process to develop and master this tech. Modi seems to have lit a serious fire under all these guys

let's see what else can be dug out

It seems strange that we would know how to manufacture single-crystal turbine blades, yet not have done this for Kaveri engine, when that's a fundamental necessity for that engine. Are you sure?

[chetak]

The Hot part of the engine and the single-crystal turbine blades are the most crucial, and most difficult to master.
We won't be getting that tech transfer as part of this deal.

Nothing is difficult if we put our heart into it. https://www.drdo.gov.in/technology-clus ... l/1529/170
We made some breakthroughs last year on the metallurgy front if I remember right. It is just that we need these platforms ASAP and adding a new engine development as part of that roadmap is quite risky. I think we need to do some crucial optimization work that Maitya ji mentioned here and that is going to take some time. It is not something that is out of reach from us. But we need time and investment to do that. We are far ahead in terms of test infrastructure compared to the 90s and we have the money to add more as needed. The collective Babu-Brass ecosystem is lethargic for sure but they are not stupid. They will take their sweet time and penny-pinch everything but there is an indigenous engine development in the road map for sure.

Besides Geopolitics has changed Khan will be more than happy if we drop a few Sudarshans in Pindi or Kashgar using their engines. There sure is going to be some leverage but how is that different from what we have today? We have a few of Khans' offensive systems already and we are still dependent on a dollar-dominated economy anyways. Russian platforms are slowly dying and the quality of their products is declining anyways. We just need to get these engines integrated and develop our own in the next 10 - 15 years.

sirji,

The design philosophy of the russki weapon systems and also their engines are very different from that of their western counterparts

A lot of the major innovations in the weapons, systems, and platforms domain have been russki originated.

It is mostly the Indian jugaad and needless fingering that causes problems. One is not saying that the russki systems don't have problems, they do, just like all gora systems also do have problems.

and, what ever the goras may say, they have no equivalent to the S-400 system.

and the russkis have already developed the S-500 system which is designed for intercepting and destroying intercontinental ballistic missiles, as well as hypersonic cruise missiles and aircraft... (and also offered to sell it to India)

[chetak]

the single-crystal turbine blades tech is already available with us and we are using it in an engine that is being made here. Don't know what percentage of indigenization has been achieved in the overall engine per se or even in the single-crystal blade itself.

Both, the engine and the single-crystal blade, seem to be working well enough.

One lab, DMRL is in the midst of a dedicated process to develop and master this tech. Modi seems to have lit a serious fire under all these guys

let's see what else can be dug out

It seems strange that we would know how to manufacture single-crystal turbine blades, yet not have done this for Kaveri engine, when that's a fundamental necessity for that engine. Are you sure?

yes, I am.

The problem with single-crystal turbine blades is that they need to be cooled properly and are meant to operate under specific temperature conditions

So this "one size fits all" concept may not be workable

I am also sure that they would have tried to adapt the existing tech already transferred and either there are material limitations which they cannot overcome so easily or even the right people may not be available to get the job done or the existing kaveri hot section may not lend itself to tinkering and use of the single-crystal turbine blades without major reworking/redesign of the engine itself

What you are basically suggesting is reverse engineering and reverse engineered the single-crystal turbine blades tailored for adaptation to the kaveri hot section environment. Reverse engineering is not as easy at it sounds. There are many more failures than successes.

Possibly the BLISK has to be re-engineered, re-tested anew for different stresses and dynamic loads, and how much can they really tinker with the existing hot section and the core flow without hitting the possibility of an almost complete redesign. This is an engine being designed for a combat aircraft.

[fanne]

I am not at all blaming the politicians - not the current one!! They will gladly throw good money after a good cause, but WILL NOT THROW GOOD MONEY AFTER A BAD/TAINTED CAUSE.

Having said that, Maitya Sir, thanks for the General gyan, can you please write some recommendation on how to go about from here? What can be done?

It looks like general public has a very simple answer if only Modi can buy them a flying testbed, the Indian engine will fly tomorrow. But in your post I have not sean one word on a flying test bed. Many things have to be done before we even get there.
What if you were the 1 person committee, to decide how we progress, how do we progress?