Kaveri & Aero-Engine: News & Discussion

Gyan · Post by **Gyan** » 22 Jun 2016 21:44

I think that we should not try to aim for unobtainable with AMCA. We should design AMCA around AL-31 with the aim to field a completely indigenous AL-31 improved version by 2030, by when serious production of AMCA might start.

brar_w · Post by **brar_w** » 22 Jun 2016 22:59

The AL-31 is a much bigger, and higher power engine for a twin engine medium weight multi-role fighter. The medium class fighter needs something in the EJ200, RD-33, F414 etc weight class with higher thrust to compensate for the ‘cost of low-observability’. With a twin AL-31 you’d end up with a much larger vehicle to support that. A move from an F414 to an AL-31 adds 900 kg of engine weight alone. On top of that you will have to adjust the design weight to compensate for a larger engine and the associated fuel load to compensate for more thrust (and weight). This has been discussed in the past in the AMCA thread. There are design implications for choosing heavier, higher thrust engines that need to be compensated for. The GE F414 EPE would deliver between 110kN to 120kN thrust and this is a more optimized solution for medium weight fighter. That 20-30% extra thrust requirement, is essentially your margin as you take a non-stealthy medium class aircraft like the Rafale and carry all mission specific internal fuel, and add a weapons bay. Go really big on thrust while still keeping a twin setup and you end up with a heavy like the F-22, not something that is at or slightly below the empty weight of an F-35.

Moreover from a design perspective, since the AMCA is being designed by the same organization that designed the LCA MK1, and MK2 the easiest and lowest risk choice from integration and design pov would be the F404, or F414 given past experience of integrating the engine. Both the EJ200, or RD33 could be looked at although it would require lots of time and money to bring those engines to the performance level of what the F414 EPE can achieve with about 4 years of remaining development. I think there may need to be a concurrent strategy to get an engine, and obtain relevant technology. Keep in mind, that what you get in return for the engine is closely related to what the deal for that engine is and what performance you are getting as well since the higher you demand, the less options you have. IMHO there is quite a bit of leg work to be done to shore up both capability (higher thrust performance from baseline F414, EJ200, M88 or RD33) and transfer of know-how. If they are working at that in a global engine market than I wonder what sort of design freeze timelines the designers are looking at since you can’t do it until you know what engine, and what charecteristics. Its difficult, costly and time-consuming to tinker around with propulsion.

Cybaru · Post by **Cybaru** » 22 Jun 2016 23:47

I think sticking to the F414 will allow it all that is needed for AMCA. Lots of thrust, commonality, doing what the koreans are doing by localization and ability to get reasonable discounts for large volumes, higher uptimes and a very decent engine to boot.

brar_w · Post by **brar_w** » 23 Jun 2016 01:55

The only propulsion program that has the diversity in need that it can leverage to fund a significantly more advanced engine, and has a lot of the leg work on that upgrade already behind it is the F414. The rest need institutional support backing up to create that business case. The KF-X, USNs F/A-18 fleet, SAAB Gripen NG, LCA MK2, and possibly USN CBARS, and the AMCA are all programs of record with a vested interest to improve engine performance and reliability for decades to come. The only thing that can tilt the equation in favor of the RD-33, EJ200 etc is some last minute extended offer on TOT. Its going to cost more in terms of capital and time to get those engines to the performance level of the EPE but of course if there is the right offer India could probably absorb a 6-8 year delay in the AMCA program. I don't think the european consortium partners have the cohesion however to all agree to co-fund this with India (they can't really agree on anything on the typhoon) so it may just be the F414 or a long protracted development project with Russia or France.

NRao · Post by **NRao** » 23 Jun 2016 02:03

I very much doubt that India will go away from GE. Just too much risk, not worth it.

IMO, India came fairly close, through the DTTI route, to getting her hands on a high tech machine, but fell a wee bit short (I think). GE was unwilling to part with certain techs, that even the GOTUS had acceded to. But, that only means no "co-design, co-develop", it does not close the door on some form of funding assistance to design+develop pretty much the same engine for the AMCA.

My feel is that the US is just too far ahead of the rest of the competitors. The rest can perhaps provide thrust, etc, but I very much doubt the efficiencies of their grow models.

Let us see.

brar_w · Post by **brar_w** » 23 Jun 2016 04:26

A lot will be known once the GE's initial deal for GE F414 is finalized, if EVER (in the form that it was announced). That deal was supposed to deliver a few engines starting last year. We haven't seen anything in the media stating that delivery. GE continues to deliver engines to the US, and Swedish programs so its quite likely that it is still stuck or pushed forward till such time as the MK2 comes closer to programatic start. The sequence would very much be F404 bulk orders (for all those MK1+'s) and then the 99 F414's. That will allow a relationship to develop at least in the assembly, and MRO side of things to allow for progresively greater transfer of technology. If the bulk orders of the F404, and the long acknowledged contract for F414 sees significant delays, I think GE will take a more cautionary approach to committing something that may be a decade or more down the road. The Koreans have partnered with western firms and have generally been looking to field complementary capability to their F-35's by late 2020's and have an incremental path to developing the KF-X. I think they in contrast will move much faster through the acquisition cycle. Plus they have a longer term relationship with GE with their T-50, and F/A-50 programs so the industry and government level partnership already exists with GE.

A quick IHS search shows that the MOD/DRDO's engine selection committee headed by Dr S Prahlada selected the F414 for the MK2 in 2010, with first deliveries for the test jets expected around Q4, 2015 with more later, with domestic production (assembly). In August, 2015 Jane's reported that the MK2 plans were to fly the craft in 2019, for an IOC of 2024. If they stick with sort of timeline, then I'd think that there is plenty of time for them to develop the relationship for the AMCA even if they select an engine now. You can then port over to the Kaveri offshoot whenever that engine's 110kN version is ready. I think folks here generally tend to underestimate the significance of shoring up propulsion prior to design freeze and how program managers and designers rely on propulsion targets to deliver specification. That relationship and comfort level is extremely important and often not spoken enough. GE has worked with multiple design teams with the F404 / 414 family. From tactical bombers, to carrier aircraft, UCAV's to single engined fighters and even tech demonstrators. I still think that the F414 has the best shot for the AMCA given that familiarity for the design team. Others do have a chance but they would really have to offer up the crown jewels to replace GE. They are already working with he engine on the MK2, so there would quite a bit of competency and expertise developed on integrating it with an aircraft, with an existing relationship with the OEM to troubleshoot and problem solve. It would be a significantly easier process compared to working with a brand new OEM, with a new engine.

maitya · Post by **maitya** » 23 Jun 2016 13:14

malushahi wrote:^^^ please consider writing a blurb for tech-and-time-challenged people like me who don't have a clue about how the above 2395 words relate to kaveri.

It is quite tempting to create a write-up to what brar_w is alluding to, of course in lay-man words, but the level of bandwidth required for that is not permitting me to even attempt it.

However, key sentence, in his quotes, is

... At the heart of adaptive engines are variable-geometry devices that dynamically alter the fan pressure ratio and overall bypass ratio, the two key factors influencing specific fuel consumption and thrust ....

And quite a bit info is scattered here and there in the Kaveri Sticky Thread as well.

If those and the "Turbofan back-of-the-envelope Performance Estimator" (found in that thread) are played around with, a lot of it will make sense as to where the current turbofan giants are aiming for.

So I will stop ... but do consider the following high-level deductions if you attempt to do the deductive analysis yourself:
1) The sledge-hammer way of increasing the thrust-level (dry) is by increasing the mass-flow

2) The mass-flow can be increased by tinkering (read increasing in mm level) the inlet diameter - so overall airframe compatibility, inlet design etc needs to be taken into account.

3) Increasing the mass-of-air thru the core - will reduce BPR - aka you are slipping back to turbojet territory

4) But plain-vanilla increasing mass-flow thru core will impact engine efficiency (read thermodynamic efficiency) - piss poor "dry SFC", leading to complaints like "fuel guzzler" etc.
As more work being extracted at HPT - will lead to reduction in work available for extraction in LPT (which drives the fan) - even more impact in stagnation pressure recovery before combustion etc.

5) The elegant way out of it is increase the OPR (actually the SPRs of both the Fan and the Compressor stages) - so that you skirt this reduction-of-stagnation-pressure-recovery issue.

6) But OPR increase will require more extraction of work at BOTH HPT (for the HPC stages) and LPT (for the FAN stages), so that the rotational energy available for these compressor stages are more than what is it now.

7) Increase in work extraction at the turbine (bot HPT and LPT) stages, means higher TeT - so better material (from thermo-mechanical efficiency stand-point), next-gen manufacturing processes (SC blades and vanes) and next-gen cooling techniques (TBC, serpentine paths for convective cooling etc)

BACK TO SQUARE ONE ... Turbofan 101 issues.

8 ) So some wise folks went and did a statistical study of which part (and what %) of a typical military flight profile is high-thrust demanding ones - and arrived at a classical contradiction of average performance vs peak-performance trade-offs. This is a pretty clever attempt to minimizing that performance gap.

Wrt Kaveri - well, these are all fancy-book stuff, as the dal-chawal basic turbofan configuration is itself not flight-qualified.

malushahi · Post by **malushahi** » 23 Jun 2016 16:49

maitya wrote:...

just the crisp explanation i was looking for. thanks maitya, mucho appreciated.

maitya wrote:Wrt Kaveri - well, these are all fancy-book stuff, as the dal-chawal basic turbofan configuration is itself not flight-qualified.

is this thread intended to be kaveri-related, or a general poop-all thread catching all and sundry about advances in powerplants? if the latter is the case, it should be renamed "General (International) Aero-engine Discussion" in order to be fair to people like me who visit brf strictly for news and discussion about bharatiya materiel development. i personally steer clear of "international" threads and spare myself the long-winded, esoteric gyan that i would much rather hear from the horse's mouth elsewhere on the web.

mods, please take note.

JayS · Post by **JayS** » 23 Jun 2016 17:58

brar_w wrote:
fundamentally the two things you are trying to decouple [are] the flow and pressure ratio through the core. Right now you increase or decrease the speed, and that is basically how you move the flow and pressure ratio, but they are closely related. If you can decouple those through variable features, you may be able to change the flow without changing the pressure ratio, or vice versa, and alter the pressure ratio without changing the flow significantly.

The variable turbine is certainly a technology of interest that we think is very powerful

Interesting....Very interesting.

Hitesh · Post by **Hitesh** » 23 Jun 2016 19:31

Cybaru wrote:I think sticking to the F414 will allow it all that is needed for AMCA. Lots of thrust, commonality, doing what the koreans are doing by localization and ability to get reasonable discounts for large volumes, higher uptimes and a very decent engine to boot.

I disagree. We need to design the AMCA around Kaveri, shortcomings and all. There is really no other way than this to establish your own independence on engine technology. You need an incubator program to make the Kaveri program succeed. Look at the past programs of USAF where they tried out like probably a gazillion models or programs before they finally acquired the know how and base of knowledge to create a cutting edge engine.

If you are not willing to do that, then do not bother calling yourself a great power to be reckoned with. We need to make the Kaveri engine program work and that means sponsoring a program and throw the whole gamut at it instead of doing it piecemeal by piecemeal on a shoestring budget.

Hitesh · Post by **Hitesh** » 23 Jun 2016 19:36

malushahi wrote: is this thread intended to be kaveri-related, or a general poop-all thread catching all and sundry about advances in powerplants? if the latter is the case, it should be renamed "General (International) Aero-engine Discussion" in order to be fair to people like me who visit brf strictly for news and discussion about bharatiya materiel development. i personally steer clear of "international" threads and spare myself the long-winded, esoteric gyan that i would much rather hear from the horse's mouth elsewhere on the web.

mods, please take note.

Then you would do well to examine the top portion of the military forum and look for the kaveri sticky. This is a discussion thread where it runs the risk of going off topic or tangent bearing some relationships to the Kaveri program. So chill and take it easy. If you can't be bothered to skim and get to what you want, that is your issue, not ours.

malushahi · Post by **malushahi** » 23 Jun 2016 20:41

^^^

who is "ours", coz i see only one gripe case here. my post was for the mods, in case you did not notice. suggest you go back and read my posts before jumping in, arm flailing, begging for attention. in any event, a mere glance at your last two posts in this thread, and the use of the word "bother" therein, demonstrates a lot about you.

NRao · Post by **NRao** » 24 Jun 2016 03:29

Look at the past programs of USAF where they tried out like probably a gazillion models or programs before they finally acquired the know how and base of knowledge to create a cutting edge engine.

Invested a lot of time. Funds. And lives.

AMCA cannot afford any of that. A Kaveri for AMCA class is perhaps 25-30 years out. Somewhere between $10+ billion. That would be pretty cheap. And you would get a few gen behind the leader.

I think it has to be done in parallel.

maitya · Post by **maitya** » 24 Jun 2016 09:06

Guys, take a chill pill - no need of fratricide, on such small issues!!

brar_w does bring a lot of interesting nuggets on various frontiers of international (read US, the leader by a gazillion miles) military technology thinking - that's a very valuable contribution in itself.
Minor nitpick that I've always had with his style of posting is not breaking up the contents into readable paragraphs (and maybe some more highlighting etc).
Those posts needs to be read carefully and analysed even more carefully to get that glimpse - ofcourse, it's not easy, but then that's the nature of the breast.

Anyway as I've said before, a very minuscule % of a typical military flight profile requires your TeT, OPR etc levels to be reaching their max design values - where the wear-and-tear (and thus the TBO) is exponentially higher.

But that peak performance can't be wished away, as those peak perf figures are matter of life and death - this is not some civilian application, where you have the luxury of designing less than optimal backup solutions and get away with it.

So the current focus is to make the whole thermodynamic and engine-aerodynamic regimes as adaptive as possible.

For example, why design the HPC/LPC stages need to always work on a typical mass-flow value ... it can still achieve a certain Thrust value with much lesser mass-flow value and bypassing a higher mass of air. So your HPT extracts less work while your LPT extracts more.

i.e. if in a typical thermodynamic cylce, the HPT is extracting 70-75% of work while the remaining 25-30% is left to LPT for all kind of flight regimes and thrust setting. Instead for a lower thrust requirement, let the HPT stage extarct 50% of work while LPT scale-up to 50%.

So the rotational energy available to the Fan is much higher than before - so that it can energize more the bypass air (increased bypass mass) and extract more thrust out of it, then it would normally do. Similarly due to lower mass-flow through core it's contribution to overall thrust reduces.

But the benefit is core-life has gone up many-fold, as the entire core now is deliberately performing at an sub-optimal levels etc.

Sounds simple ... nothing but!!

As it requires very very very careful re-designing of the whole thermodynamic cycle ... if the OPR contribution of the HPC stages too low, the combustion itself will suffer (lower than normal stagnation pressure recovery etc) and the TeT will also suffer. Resultant would be very drastic drop in thermal efficiency etc, and the whole thing goes into a downward spiral.

So, the grand-mullah enquoobuddin-al-turbini once sermoned, many many many moons back, that there's no easy path in any serious turbofan development (PissBUH).

Manish_Sharma · Post by **Manish_Sharma** » 24 Jun 2016 11:30

Hitesh wrote:
I disagree. We need to design the AMCA around Kaveri, shortcomings and all. There is really no other way than this to establish your own independence on engine technology.

This suggestion will be a killing blow to AMCA. It sounds very patriotic and all.

But this will actually make both the AMCA and Kaveri the punchbags for our anti-indigenous media. With every delayed timeline, every hiccup will be magnifyed zillion times and presented as if only and only Bharat is struggling with such an easy jobs as designing an air force fighter jet and its engine.

We will be forced to go more more fgfa and f 35s.

Perfect situation = AMCA with Kaveri both performing to best of expectations.

Ok situation = AMCA with foreign engine and both performing to best of expectations.

Bad situation = AMCA design and a/c works fine but Kaveri doesn't work as expected so both go down together, along with "....ok we kalurams can't design these things, so better give up and go to russians and americans and french and south koreans and japanese and french only..."

or swedish !

Kaveri should be continued for AMCA and UCAVs. But AMCA should not be tied down solely to Kaveri.

Else you will be writing on how Vayu Sena has no choice but to go for more fgfa and f35s.

JayS · Post by **JayS** » 24 Jun 2016 13:17

maitya wrote: However, key sentence, in his quotes, is
... At the heart of adaptive engines are variable-geometry devices that dynamically alter the fan pressure ratio and overall bypass ratio, the two key factors influencing specific fuel consumption and thrust ....

How is Fan PR changed?? More aggressive Variable geometry stators than what we have already??

Later added: May be its variable speed Fan.

maitya wrote: Turbofan 101 issues.

Surprisingly enough I have seen that even many of the engineers who are working on Jet engine components for yrs in industry don't understand how High BPR actually helps in better efficiency. I find it easier to explain them with the help of simple thrust equation (neglecting mass of fuel added, difference in pressure at front and back).

T = (mdot_out * V_exit) - (mdot_in * V_in)
energy_out = 0.5 * mdot_out * Vexit^2

Basically you add energy/momentum to incoming air with incoming energy/momentum using chemical energy and then extract that momentum in terms of a force i.e. thrust. Now the efficiency depends on how well you can extract the added energy into useful work i.e. how less is wasted energy. Since incoming momentum (mdot_in * V_in) is a fixed quantity under given conditions, to maximize thrust you need to maximize outgoing momentum (mdot_out * V_exit). So given incoming momentum and required Thrust value, your outgoing thrust is fixed. Now to increase efficiency at this thrust you need to minimize the energy thrown out which is (0.5 * mdot_out * Vexit^2). If one observes, there are two variables in momentum and energy equations - mass and velocity. To maintain thrust you have to maintain certain exhaust momentum - but the same level of momentum can be gained with either mass or with velocity at each others expense - momentum is directly proportional to both of them. OTOH the energy waste is directly proportional to only mass but proportional to the ''square'' of Velocity. So if you want to achieve certain thrust - you can either move more mass with smaller velocity or you can move smaller mass with higher velocity. But the energy wasted is much more in the later case.

For example - if you want 3 units of thrust and the incoming air has 1 unit of momentum with it, you need to add 3units of momentum to it making exhaust momentum 4unit. Now you can get this 4 units either with 1unit of mass going at 4 units of velocity or with 4units of mass going at 1unit of velocity. Thrust will be same but the energy loss in first case will be 2units while for the later it will be 8units..!! (extreme cases just to emphasize the point) That is first way of getting thrust is less wasteful i.e. more efficient. This is high BP approach and the later case is the low BP approach as far as turbofans are concerned. The higher the BP, higher is the mass being moved with lower velocity at same thrust level. Obviously it will be higher in efficiency.

Hitesh · Post by **Hitesh** » 24 Jun 2016 18:00

Dhananjay wrote:
Hitesh wrote:
I disagree. We need to design the AMCA around Kaveri, shortcomings and all. There is really no other way than this to establish your own independence on engine technology.
This suggestion will be a killing blow to AMCA. It sounds very patriotic and all.

But this will actually make both the AMCA and Kaveri the punchbags for our anti-indigenous media. With every delayed timeline, every hiccup will be magnifyed zillion times and presented as if only and only Bharat is struggling with such an easy jobs as designing an air force fighter jet and its engine.

We will be forced to go more more fgfa and f 35s.

Perfect situation = AMCA with Kaveri both performing to best of expectations.

Ok situation = AMCA with foreign engine and both performing to best of expectations.

Bad situation = AMCA design and a/c works fine but Kaveri doesn't work as expected so both go down together, along with "....ok we kalurams can't design these things, so better give up and go to russians and americans and french and south koreans and japanese and french only..."

or swedish !

Kaveri should be continued for AMCA and UCAVs. But AMCA should not be tied down solely to Kaveri.

Else you will be writing on how Vayu Sena has no choice but to go for more fgfa and f35s.

I am sorry but there are no shortcuts to get the engine we want. The F-16A/Bs suffered engine problems in the beginning of their lives and people were calling F-16s a joke and a waste of money but the US stubbornly stuck with the program and the engine program and now it is a great platform. Same thing with F-4 Phantoms. Result? Cutting edge programs like the F-22 plane and JSF with extraordinary engines.

To get the engine we want, we need an incubator program that offers a host for the kaveri engine warts and all and allow the designers and engineers to iterate better designs along the way until we get what we want. Otherwise, we would be stuck waiting forever for the engine we want like the poor bums waiting for godot not knowing if he would ever come.

Kakarat · Post by **Kakarat** » 15 Aug 2016 01:48

Time to restart our regular discussions

France offers EUR 1 billion to revive India's combat jet engine project

SaiK · Post by **SaiK** » 15 Aug 2016 09:34

not spending money should take lower priority than not owning the IPRs.

Kakarat · Post by **Kakarat** » 15 Aug 2016 10:32

In my opinion a Partly French Kaveri is better than a fully American engine, it would be even better if GOI pushes French for 100% TOT and Make in India for the French developed parts of Kaveri without stopping the other ongoing engine development efforts

maitya · Post by **maitya** » 15 Aug 2016 13:42

^ Depends ... if this is another back-door attempt to implement Eco/M88 etc core while retaining the FADEC algo etc, then we are back to square one as far as developing indigenous turbofan development and manufacturing capability is concerned.

However, if it's all about taking the Kabini core and introducing more mature technology (mostly manufacturing) to take it to a 30+ OPR and >1800K TeT regimes, and thus incrementally improve the thrust levels, I'm all for it.
Higher thrust versions can be built around this core as well, by slightly increasing the mass-glow-thru-core by tinkering with the inlet diameter etc. - that'd be the natural progression in the dev work.

But I seriously doubt the French would barter away their hard earned turbofan tech in doing so (for reference GEs refusal to take the bite in-spite of F404 and F414 lic manufacture offers etc.).

Let's wait and watch!!

NRao · Post by **NRao** » 15 Aug 2016 17:02

BK observes:

The French negotiating strategy is plain enough in retrospect. This is because soon after Rafale’s selection, SNECMA called off the negotiations, begged off the deal. Now to get the Rafale over the finish line, they are falling back on the same old tactics. This time another French firm promising to get the Kaveri off and running just so long as Delhi signs on the dotted line. Obviously, the day the Rafale ag is initialed is when Safran will withdraw its offer. What’s the sacrifice of $1.4 billion—assuming a penalty is imposed should Safran fail to deliver as inevitably it will—if it fetches $30+ billion in return?

The $30 billion - is the projected life time cost of purchasing the Rafale.

Vivek K · Post by **Vivek K** » 15 Aug 2016 21:52

India needs to attach more funds for the Kaveri program development and use its indigenous industrial base. This will take time. All TOT is a lie meant to fool the public and get the contract. The French wouldn't give this tech to their mother so the question of passing that to SDRE Indians does not even arise.

Shake up GTRE and put a good leader as its head (maybe from HAL's Engine Divisions). Provide more funding for testing facilities (flying testbed or testbeds), recruit aggressively (look for expats also), consider reverse engineering.

This lie about 25-30% behind is in contrast to 5% lag in the thrust.

Indranil · Post by **Indranil** » 15 Aug 2016 23:00

GTRE has put out a tender for setting up of Twin Test Cell for developmental aero gas turbine engines upto 130kN thrust class.

There are some interesting details of the engine and the facility.

Indranil · Post by **Indranil** » 16 Aug 2016 01:18

Unfortunately, I missed out saving the tender that HAL put out for the production of parts for the HTFE and HTSE engine. That tender spelt out the basic features of both the engines in development within HAL.

However some more tenders for HTSE.
CASTINGS FOR NGV & REAR BEARING SUPPORT
SUPPLY OF SINGLE CRYSTAL BLADES

Indranil · Post by **Indranil** » 16 Aug 2016 01:18

According to NAL's annual report, its rotary engine has been uprated to 65 hp (from the current 55hp) for use in the Panchi UAV.

Will · Post by **Will** » 17 Aug 2016 02:26

They seriously need a flying testbed along with associated facilities.

Indranil · Post by **Indranil** » 18 Aug 2016 23:12

Flying testbed for what kind of engine?

Pratyush · Post by **Pratyush** » 19 Aug 2016 11:32

At minimum Kaveri and it's future derivatives family.

JayS · Post by **JayS** » 20 Aug 2016 19:42

Thanks a lot IR for the updates. These HAL guys are unbelievable. They have given out drawing with aerofoil co-ordinates in the tenders. Tomorrow when HAL becomes lead integrator and outsource all parts from outside, will the be publishing entire engine design like this in various tenders??

The specs given in test cell tender looks quite close to Al-31FP engine apart from the much higher dry thrust. Have they just given out the new Kaveri engine that they started designing?? If so then the dry thrust rating is fantastic, I would say.

SaiK · Post by **SaiK** » 22 Aug 2016 05:05

http://idrw.org/gtre-plans-to-set-up-ne ... ust-class/
from where do these pics come from?

ranjan.rao · Post by **ranjan.rao** » 22 Aug 2016 06:13

^^^googleshwara?

nash · Post by **nash** » 22 Aug 2016 08:48

Here is the tender link:

http://www.drdo.gov.in/drdo/tenders/vie ... icro=18043

As per Enclosure-1:

Engine Weight 2170 kg
Engine Length 4970 mm

Dry thrust 90 kN
Reheat thrust 130 kN

Weight is on the higher side, may make it overweight.

JayS · Post by **JayS** » 22 Aug 2016 14:26

^^Don't get disheartened, the max weight spec is most probably due to extensive instrumentation the test engines carry. Installed engine will be lighter. Also having full axisymmetric TVC adds significant weight. If the specs are copy paste of new engine they are making then be assured it will be at par with Al-31FP in terms of wet TW ratio if not better, but of coarse much better in dry TW ratio. Its comparable to GE F110 and PW F100 series engines. I must say dry thrust of 90kN is quite ambitious. I was expecting around 70-75kN with wet thrust of 120-125kN for the new Kaveri engine. Of coarse this is all given the specs are for new engine exactly. Also a thing to keep in mind is TVC reduces effective thrust due to losses associated with them. I have seen number around 10-15% for circular exhaust jets while as high as 20-25% for square exhaust jets like in F-22.

SaiK · Post by **SaiK** » 22 Aug 2016 16:55

The weight alone doubles comparing the 70-80kN to 130.
T:W ratio?

We have to assume the worst case rather dream on a super-duper engine that never sees light.
else, show me the design

Will · Post by **Will** » 23 Aug 2016 00:08

It says "upto" 130kN. Probably keeping in mind future requirements.

SaiK · Post by **SaiK** » 05 Sep 2016 06:54

Ceramic Composites Revolutionize Engine Efficiency
http://www.nasa.gov/feature/ceramic-com ... efficiency

Prem · Post by **Prem** » 05 Sep 2016 10:35

SaiK wrote:Ceramic Composites Revolutionize Engine Efficiency
http://www.nasa.gov/feature/ceramic-com ... efficiency

And A desi is running GE CMC programme.
https://www.youtube.com/watch?v=is1BBilkyUM

SaiK · Post by **SaiK** » 06 Sep 2016 00:20

what does it tell?

hint: it is about Indian institutions

Prem · Post by **Prem** » 06 Sep 2016 03:08

SaiK wrote:what does it tell?

hint: it is about Indian institutions

Recall, P & W Jet Engine Programme for F35 also being run by young DESI chap who was twice rejected by DRDO.