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Kaveri & aero-engine discussion

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shiv
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Re: Kaveri & aero-engine discussion

Postby shiv » 31 Dec 2017 12:59

JayS wrote: Dont fix whats not broken.

Don't break what can't be fixed is an equally vital principle. One cannot compromise on factors that cannot be predicted. If different gun propellant powders and 23 mm shell varieties or newer missiles that might appear in future cannot be predicted, the design has to avoid gas ingestion and cannot be more lax with a newer model "more tolerant" engine and less lax with an older model engine. I cannot imagine a designer saying "It's OK if some gases are ingested. That is imprecise and a formula for disaster. "How much gas gets ingested and under what conditions" would be critical. Unless that is studied by testing there will be needless accidents. That is the reason why testing takes time, which is where the discussion started.

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Re: Kaveri & aero-engine discussion

Postby Indranil » 31 Dec 2017 13:22

And if you ask me, this is where the discussion should end. We have gone round the circle at least once.

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Re: Kaveri & aero-engine discussion

Postby ramana » 31 Dec 2017 13:42

Abhibhushan wrote:Re heat and dust of India and Aero engines.

An annecdotal piece of info

In 1947 - 48 we had purchased the Hawkwers Tempest II as our main ground attack aircraft. The aircraft was powerful and effective for its role. It was powered by a radial engine that used a conceptually ‘new’ rotating sleeve valve. These engines worked well in Europe. Unfortunately, the sleeve valve technology could not survive in the Indian environment. Fine dust in the air of northern India started to jam these valves often. We had to admit defeat and junk the fleet of Tempest II by 1953/54.


What do you make of this gun firing brouhaha for LCA?

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Re: Kaveri & aero-engine discussion

Postby Thakur_B » 31 Dec 2017 15:27

prasannasimha wrote:They went to IIT's and NIT's for recruitment and guess what the number was zero. . They have asked for university integration guess what zero. Easy to say Hire and fire when you can't hire in the first place.


Is this a recent phenomenon? My classmates/batchmates were selected from campus selection and one of them made an important contribution to the river project as well.

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Re: Kaveri & aero-engine discussion

Postby prasannasimha » 31 Dec 2017 19:10

IIST was started as Madhavan Nair APJ Kalam got zero people coming for IIT's to ISRO and DTDO. The ones they wnated refused and the ones they got were not adequate in their knowledge and they then thought they should start an Institute to train people for their requirements.

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Re: Kaveri & aero-engine discussion

Postby chetak » 01 Jan 2018 15:35

shiv wrote:
chetak wrote:never ever heard of an engine that requires overhaul more frequently because of gun firing but I have heard of airframes that add extra time to the airframe hours whenever an armament related sortie is flown.

This is because gun gases are prevented from entering engines by rigorous testing. Air Marshal Rajkumar in his chapter in the MiG 21 history book says that K-13 missile firing was always done only after turning on the engine relight switch.


many airline companies and also many mil operators have SOPs that require that the ignitors are turned on during heavy rain too.

The position of the guns are usually dictated by the aircraft geometry and not many positions are available either to mount internal guns or gun packs. Testing and firing limitations have to be determined keeping these constraints in mind.

Almost always its a tradeoff.

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Re: Kaveri & aero-engine discussion

Postby chetak » 01 Jan 2018 16:38

shiv wrote:
chetak wrote:
How come other manufacturers haven't ever reported such unique conditions which would have resulted in a lot of engine testing in such "unique" Indian conditions??

They have - but this is about the air force. I have heard (literally) that wear and tear of IAF engines is higher because of smoke and dust. But I am unable to provide a source - will try and locate one.


let me give you the example of flying in goa. The IN flies predominantly from coastal bases and different contaminants affect IN engines. That's why IN aviation, (as well as non aviation) equipment is "marinised" The IN engines, the airframes and the LRUs are much more expensive because of such "marinisation" incorporated into the design, build as well as the extensive + expensive lengthy testing procedures required for the qualification of such equipment.

The goan air has a very high particulate matter content and the particulate matter is predominantly iron ore dust. This comes from the open cast mining practiced in goa.

Goa has a saline atmosphere like any coastal city/state due to the high saline content of the sea air.

So, you wind up with salt, water, and iron which when put together forms a perfect battery compromising anode, cathode, and electrolyte. Currents flow in these localized batteries and produce corrosion of the engine blades apart from the abrasive problems posed by such particulate matter

I still remember, after all these years, the utter surprise and deep shock on the face of a gora tech rep when we "washed" a running engine in front of him by pumping a mixture of distilled water and some chemicals directly into the intake of a running engine. The process took 25 minutes to complete and he was in a great panic throughout and he tried to stop us many times. For us, it was merely a mundane procedure that we carried out regularly and as a matter of routine.

Our procedures were not even known to the Designer/manufacturer of the engine nor was anyone else interested in following our procedures which served us very well in safeguarding our engines.

The dazed gora tech rep later asked if he could have a copy of our "washing" procedure and it was willingly given to him.

Much later, I heard that some others in India also started "washing" their engines when earlier they had loudly laughed at us.

Engines with a high magnesium content tend to have corrosion and other abrasion problems, especially in an atmosphere like goa. Many many countries have similar or even more diverse airborne particulate and chemical issues in their atmospheres. P&W seems to be flying OK there or is it simply too expensive to talk of "special conditions", especially when lawyers also attend tech meetings in those countries??

These days magnesium is mostly out and/or other alloys have taken their place which are treated and show vastly improved performance in the presence of contaminants both particulate as well as chemical.

So when some joker from P&W condescendingly yaps about the "special conditions" in India, its pure, unadulterated BS and someone there thinks that he has bamboozled us dumb SDREs.

In some form or the other, such conditions obtain all over the world. and their piss poor new gen 321 engines are supposed to perform, notwithstanding, and if they do not, it can usually be traced back to a design issue.

There is enough shooklaw type paid media to carry fake news in every part of the world, especially when hired gora guns are hunting SDREs just to silence them.
Last edited by chetak on 01 Jan 2018 16:49, edited 1 time in total.

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Re: Kaveri & aero-engine discussion

Postby Abhibhushan » 01 Jan 2018 16:45

Ramana wrote
Re heat and dust of India and Aero engines.
What do you make of this gun firing brouhaha for LCA?


Gun gas ingestion is an old challenge for a designer. We had our full measure of gas ingestion problem with the Gnat. Finally we accepted the aircraft with a compromise solution: the engine power was reduced automatically by a ‘Dip Switch’ if guns were fired above 20000 feet altitude. (Fortunately, the Gnat never faced an enemy at above 20K in its total operational life.

Problems faced by the Tejas will also be overcome, through technology or through operational techniques/compromises)

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Re: Kaveri & aero-engine discussion

Postby JayS » 01 Jan 2018 17:30

chetak wrote: when we "washed" a running engine in front of him by pumping a mixture of distilled water and some chemicals directly into the intake of a running engine.


Now that's what I call it "Badass". :wink: Very interesting info. Thanks for sharing.

Which engine was that.? If you don't mind sharing..

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Re: Kaveri & aero-engine discussion

Postby chola » 03 Jan 2018 15:02

Time to set up multiple engine development oganizations, including the private sector, that can compete with each other.

If not, even a successful SNECMA Kaveri won’t make much of a difference. We need an INDUSTRY not a singular project.

The PRC looks like it had broken through the engine barrier in 2017 with a flood of new prototypes and tests. Maybe dhoti-shivering can create some urgency.

Posted in AFM:
https://forum.keypublishing.com/showthread.php?140394-Chinese-air-power-thread-18&p=2424982#post2424982

2017 Engine Advances
1) WS-10 variant on J-20 bort number 2021

2) WS-10X with AVEN nozzles on a J-10B/C

3) WS-19 engine prototype assembled *

4) WS-20 engine nearing testing on Y-20

5) CJ-1000A prototype assembled **

6) WS-15 reported in March to be “ready soon” ***

7) WZ-10 turboshaft reported to be ready and powering Z-20 prototypes

8 ) 2nd FC-31 prototype reportedly flew with WS-13

* The WS-19 is to be the uprated engine to be paired with the FC-31 which is increasingly cited as the next Chinese carrier fighter.

** The CJ-1000A is a LEAP-level domestic engine from ACAE, a commercial engine builder, for the C-919

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Re: Kaveri & aero-engine discussion

Postby shiv » 03 Jan 2018 20:31

As the video below shows, jet engines are designed to tolerate water well. It is small solid particles that cause damage. Smoke by definition includes small particles - apart from hot gases that may result from gun/missile plumes. Engine blade tips that rotate reach near supersonic speeds - which means each particle of dust is a little bullet that chips off a little bit of blade. Not much - but over time it accelerates damage.
https://www.youtube.com/watch?v=faDWFwDy8-U

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Re: Kaveri & aero-engine discussion

Postby JayS » 03 Jan 2018 20:56

shiv wrote:As the video below shows, jet engines are designed to tolerate water well. It is small solid particles that cause damage. Smoke by definition includes small particles - apart from hot gases that may result from gun/missile plumes. Engine blade tips that rotate reach near supersonic speeds - which means each particle of dust is a little bullet that chips off a little bit of blade. Not much - but over time it accelerates damage.
https://www.youtube.com/watch?v=faDWFwDy8-U


Indeed. A very good video you might like to watch showing this damage and how to repair it. Actually 2 parts. (PS: This channel is very nice for a jet engine stuff). Composite fan blades have Ti leading edges to make them damage tolerant from all kind of damage including this.

https://www.youtube.com/watch?v=p5doVAKb4Ro

Also you may know already, civilian engines have mechanism to throw out foreign objects after booster/LPC from the core flowpath. Its based on inertia so bigger particles typically get removed here. Its the medium to fine particles which must be getting in mostly. Apart from mechanical damage to compressor, they can also block cooling holes on turbine blades. I would say, its the medium size of particles which would be most dangerous for the engine. Finer particles are relatively easy to be swept away by airflow. Mechanical properties such as hardness of the particle would also be an important factor.

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Re: Kaveri & aero-engine discussion

Postby JayS » 05 Jan 2018 01:03

Abhibhushan wrote:
Ramana wrote
Re heat and dust of India and Aero engines.
What do you make of this gun firing brouhaha for LCA?


Gun gas ingestion is an old challenge for a designer. We had our full measure of gas ingestion problem with the Gnat. Finally we accepted the aircraft with a compromise solution: the engine power was reduced automatically by a ‘Dip Switch’ if guns were fired above 20000 feet altitude. (Fortunately, the Gnat never faced an enemy at above 20K in its total operational life.

Problems faced by the Tejas will also be overcome, through technology or through operational techniques/compromises)


I suppose for trying to stop engine surging or help it recover post surge due to hot gas ingestion during missile/rocket firing, reducing engine power by reducing fuel flow and changing compressor IGC positions to increase surge margin are standard methods. FADEC takes care of these changes when rocket/missile is fired. The aircraft sends signal for firing to engine FADEC and then FADEC reduces engine power and adjusts IGV for a short while.

Here is a paper which talks about issue of engine surge due to rocket firing on AH-1 Cobra Helicopter.

http://www.dtic.mil/dtic/tr/fulltext/u2/a290130.pdf

The AH-1 Cobra helicopter has the capability to launch 2. 75 inch folding fin aerial rockets (FFARs)
equipped with Mark 66 (MK66) rocket motors to engage battlefield taigets. Following a class A
accident in which an AH-1 suffered. a tail rotor drive shaft milure while launching MK66 FFARs,
a joint engineering investigation of the AH-1F helicopter was conducted by the Airworthiness
Qualification Test Directorate (RQTD) of the U.S. Army Aviation Technical Test Center and the
U.S. Army Aviation Applied Technology Directorate (AA1D). The results of this investigation
which recommend an engine inlet shield to defiect rocket exhaust gases away from the engine
are
oontained in a U.S. Army Test and Evaluation Command (TECOM) Fmal Report, TECOM Project
No. 4-C0-2~16, dated June 1991.
Subsequent to this work, the U.S. Army Avi3tion Systems Command (AVSCOM) in conjunction
with the NASA Lewis Research Center directed Chandler Evans, the engine fuel control supplier
for the AH-1 helicopter, to investigate potential modifications to the fuel control to alleviate the
rocket fire surge problem. The work at Chandler Evans WclS based on a computer simulation of the
engine, fuel control, and AH-1 helicopter.
The objective of the investigation was not to preclude engine smge following hot gas ingestion but
to recover smoothly from surge and avoid overtorqueing the rotor drive system. This objective, if
achieved, would have application not only to rocket firings, but to helicopter operation in general
where inlet distortion effects and engine deterioration can also cause the engine to surge and
potentially cause damage to the rotor drive train
.


The fuel control system must be modified to actively prevent engine surge or to ~ to engine surge
in some fashion to attenuate rotor drive train torque spikes.
In an attempt to prevent surge, it was assumed that closure of the compressor inlet guide vanes
(IGVs), when synchronized with rocket firings, could go a long way to block the amount of hot
gases· entering the engine and thereby preclude surge. The IGV s must be modulated between the
open and closed position for each rocket fire because closing down the IGVs for a prolonged time
period would degrade engine power and cause loss of rotor speed and helicopter lift.


Note that as I said earlier, the main culprit is the hot gases which cases inlet distortion (and high temp of intel air to obviously) which causes surge in turn.

Next, I found a mention in one old reference for F404, that F404 also has this function in its FADEC. Which means there is a every possibility that LCA also be able to utilize this functionality for handling engine surge due to any kind of hot gas ingestion from gun/missile/rocket firing.

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Re: Kaveri & aero-engine discussion

Postby ramana » 05 Jan 2018 01:12

Wow, So it can be handled by software fix using the FADEC as the Dip Switch.

Maybe its already enabled for all we know if older references to F404 have this feature.

Can you post this for further reading?

So can lurk back till further news.

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Re: Kaveri & aero-engine discussion

Postby shiv » 05 Jan 2018 07:38

JayS wrote: Which means there is a every possibility that LCA also be able to utilize this functionality for handling engine surge due to any kind of hot gas ingestion from gun/missile/rocket firing.

There is every possibility that all this may be completely unnecessary if the gun positioning is good enough - but only comprehensive testing can prove that - without waiting for an American termed "Class A" accident. I think a class A accident is a write off. This is after all how this discussion started "Why don't they get on with gun integration?" The Cobra accident example shows how a well established airframe can show up unexpected problems from different munitions.

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Re: Kaveri & aero-engine discussion

Postby JayS » 05 Jan 2018 12:17

ramana wrote:Wow, So it can be handled by software fix using the FADEC as the Dip Switch.

Maybe its already enabled for all we know if older references to F404 have this feature.

Can you post this for further reading?

So can lurk back till further news.


http://www.dtic.mil/dtic/tr/fulltext/u2/a164562.pdf

Aussie paper from 80s. Has a mention of FADEC modes.

Another interesting fact mentioned in paper is the underestimation of Time at max temperature and time of AB usage during design of F404. Or rather overutilization of engines in real life depending on how you want to see it. Real life values of these two parameters were 60% higher. I had posted on BRF earlier how F404 has severe life issues during service until mid 90s. Now I know why. GE ironed out the issues eventually.

Another one, this paper says one key outcome of F404 project in realization of how much more Low Cycle fatigue is important for engine life. By merely keeping track of Equivalent Design Cycles actually utilized in real life one can increase engine utilization significantly and also manage MRO schedule much better. This is the genesis of Life Tracking System in GE Engines, I think. RM12 has seen significant hike in utilization of engines (I am not sure if the figure is in public domain already, so wont post) Similar approach for airframes can also increase utilization of airframes significantly. I was delighted to know during recent Aero India that Kaveri also has Life Tracking system. The snecma guy told me they had this system in all their engines right from starting (like 50s/60s). But I don't believe him. Can't take marketing guys at face value :mrgreen: .

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Re: Kaveri & aero-engine discussion

Postby JayS » 05 Jan 2018 12:21

shiv wrote:
JayS wrote: Which means there is a every possibility that LCA also be able to utilize this functionality for handling engine surge due to any kind of hot gas ingestion from gun/missile/rocket firing.

There is every possibility that all this may be completely unnecessary if the gun positioning is good enough - but only comprehensive testing can prove that - without waiting for an American termed "Class A" accident. I think a class A accident is a write off. This is after all how this discussion started "Why don't they get on with gun integration?" The Cobra accident example shows how a well established airframe can show up unexpected problems from different munitions.


Of course, first thought in designer's mind it to eliminate any anticipated/known issue. But if it cannot be eliminated, then it has to be dealt with somehow. This power adjustment is the second approach. But note that the mode is also useful in other scenarios, for example, at high AoA when airflow might be reduced somewhat, or under severe sideslip.

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Re: Kaveri & aero-engine discussion

Postby ramana » 28 Jan 2018 05:26

4 problems described

http://www.delhidefencereview.com/2017/ ... ssion=true



The key problems encountered by the Kaveri design, according to sources who have formerly been associated with the program, are:

Unacceptable levels of fan-blade flutter risk – It seems that the Kaveri intake may need some redesign to reduce the chances of stall inducing self-excited vibrations (flutter) being experienced by the engine’s duct fan blades.


Reheat oscillations – Kaveri prototypes currently experience significant combustion oscillation in their augmentors/afterburners. This also has an impact on specific fuel consumption during reheat.


First stage low-pressure compressor blade vibration – The Kaveri’s first stage low-pressure compressor is also experiencing worrisome levels of rotor blade vibrations at the moment.


The issues delineated above have been deemed rectifiable by those in the know. But it seems outside consultancy support will be needed for the same. That, is a story for another day.



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Re: Kaveri & aero-engine discussion

Postby ramana » 28 Jan 2018 05:35

I don't know if they can make the 52 KN non reheat version?

Would be useful.in.many configurations.

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Re: Kaveri & aero-engine discussion

Postby NRao » 28 Jan 2018 06:25

That list is from 9 months or so ago.

Any chance they have knocked out one or two of them by now?

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Re: Kaveri & aero-engine discussion

Postby Yagnasri » 28 Jan 2018 06:46

S Jha said that he will write more on this. Hope more details come out.

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Re: Kaveri & aero-engine discussion

Postby chetak » 29 Jan 2018 13:40

ramana wrote:Wow, So it can be handled by software fix using the FADEC as the Dip Switch.

Maybe its already enabled for all we know if older references to F404 have this feature.

Can you post this for further reading?

So can lurk back till further news.


AFAIK, the critical phenomena of engine surge and stall is not fully understood.

There was/is extensive work going on but I have not heard of any definitive conclusions.

This is also a huge factor in the resolution of these phenomena.

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Re: Kaveri & aero-engine discussion

Postby srai » 29 Jan 2018 16:49

ramana wrote:I don't know if they can make the 52 KN non reheat version?

Would be useful.in.many configurations.


Planned for Aura UCAV.

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Re: Kaveri & aero-engine discussion

Postby shiv » 31 Jan 2018 10:11

Cross post
https://www.airspacemag.com/military-av ... 180947758/
Keen to thaw Anglo-Soviet relations, British Prime Minister Clement Attlee invited Soviet scientists and engineers to the Rolls-Royce jet facility to learn how the superior British engines were made. Attlee further offered to license production to the USSR—after exacting a solemn promise that the engines would be utilized only for non-military purposes. The offer stunned the Americans, who protested loudly. And the Soviets? Russian aviation historian and Ukrainian native Ilya Grinberg says, “Stalin himself couldn’t believe it. He said, ‘Who in their right mind would sell anything like this to us?’ ” Grinberg, a professor of technology at the State University of New York at Buffalo, points out that the presence in the delegation of Artem Mikoyan himself—the “Mi” in MiG—should have been a tip-off to what in fact ensued: The Rolls-Royce samples shipped to the USSR in 1946 were promptly installed into MiG-15 prototypes and successfully flight-tested. By the time the fighter was ready for mass production, the Soviets had reverse-engineered the Nene; their copy was designated the Klimov RD-45. When the British objected to the violation of their licensing agreement, says Grinberg, “the Russians just told them ‘Look, we incorporated a few changes. Now it qualifies as our own original design.’ ”

But as in the case of post-war Soviet duplicates of western European autos, craftsmanship in the Soviet engine copies compared unfavorably to what went into the real thing. The time between the introduction of the Klimov engines and their failure was measured in hours. “Knowing the general state of the Soviet aviation industry at the time,” Grinberg says, “quality control throughout the entire MiG was not what you would expect in the west.” Materials for high-stress parts were substandard. Tolerances were not precise. Indeed, some performance problems on individual MiGs were traced to wings that didn’t exactly match. Grinberg describes a Russian archival photo of production line workers casually installing an engine in a first generation MiG-15. “How shall I say this?” he says, hesitantly. “It’s not exactly people wearing white overalls in a high-tech environment.”

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 04 Feb 2018 23:58

Posted by BRF Member ashish raval

----------------------------------------

A research organisation does not need CFD tools to design a jet engine. All jet engines were designed pre advent of CFD tools in the past. Even if CFD tools are required, a research organisation should have enough mathematical expertise to write it. That is minimal basic requirements. Without these if cannot be deemed to be capable of designing and as far as I know desi scientists toiled hard in those days to learn it from the scratch and some produced very good papers in these fields.
It should be provided to research organizations (multiple private players) in the current form with design rights to be improved and in return these organisations can make money by selling jets overseas and expanding. They should be able to improve design in less than five years, I bet.

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 04 Feb 2018 23:59

Posted by BRF Member nvishal

----------------------------------------

Can someone who is following this section, comment on the status of the Kaveri program?

Any official word?

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 05 Feb 2018 00:00

Posted by BRF Member dinesh_kimar

----------------------------------------

^ Reading Livefist on the Ghatak program:
1. His "sources " assert that with French technical assistance, Kaveri will be the main engine on the LCA and AMCA.
If this is true then:
- Kaveri will have at least 85 KN, to be more powerful than the F404.
- Might probably have a SNECMA core, which is scalable up to the 110 KN required for AMCA.
- We won't be ordering any more F-404s from GE.(20 ordered for the prototypes and licensed manufacture for 99, won't be enough for the 123 firm orders in hand, and I guess should be ordered before 2018-19 in order to meet schedules.Hasn't happened yet.)
- So, a 50-60% Kaveri is coming?

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Re: Kaveri & aero-engine discussion

Postby dinesh_kimar » 05 Feb 2018 00:07

A Kaveri poster from one of the Expos (from memory, theres a 3D printed model of Kaveri also shown, i think) shows the blades mounted on the disc, and with some kind of a damper at the root of the blade. Perhaps to reduce blade vibrations , changing frequencies and harmonics. The Gurus can enlighten us better-maitya Saar , Yak herder,etc.

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Re: Kaveri & aero-engine discussion

Postby SaiK » 05 Feb 2018 01:45

Yagnasri wrote:S Jha said that he will write more on this. Hope more details come out.


There was the article on SGTJE (small gas turb jet eng), but that was drdo/nal work for a new small ucav - around 2.69kN.

Jha did come out with those details (see ramana's post above): [you can't get a white paper though :)]

1. reheat oscillations
2. 1st stage low comp blade vibrations
3. excessive fan-blade flutter risks

These are the main concerns, and I am dismayed we are not capable here. moi thinks it is all our precision system issues. we need to get outta too many "old jugaad jigs" [express]

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Re: Kaveri & aero-engine discussion

Postby nvishal » 05 Feb 2018 11:59

Livefist in march 2017
https://www.livefistdefence.com/2017/03 ... noise.html
Under the terms of the partnership finalised late last year , Snecma is working to modify, certify and integrate the Kaveri on a Light Combat Aircraft airframe before 2020.


There's also this from Rosoboronexport from August 2017
http://roe.ru/eng/press-service/press-r ... -projects/
“At present the majority of company’s joint R&D projects are with India and China. The projects focus on cooperation in the field of space, naval, air defense and army equipment, as well as other hi-tech projects. One of the most vivid illustrations is the KAVERI Indian aircraft engine. We have been involved in its development, modification and trials. The project is about to be over soon”, - Alexander Mikheev added.

Russian element is just for testing I guess

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Re: Kaveri & aero-engine discussion

Postby ramana » 06 Feb 2018 03:57

One thing that bothers me is it's not like Kaveri was dreamed up alone on the banks of the Tungabhadra by GTRE.
There were many French engineers trouble shooting the Kaveri program all along from beginning. So where is this sudden offset support coming from?
I think every one is taking India for a ride on the Kaveri engine boondoggle.

GTRE humble engineers keep giving hopeful interviews to jingo press reporters who dutifully report and now tweet to their followers these hope filled nuggets.

Not one real milestone plan is announced...

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Re: Kaveri & aero-engine discussion

Postby NRao » 06 Feb 2018 07:15

I *think* everything is going according to script.

I *think* India has proposed that the collab with a foreign entity 1) use the current Kaveri as the baseline + 2) that the foreign entity use their deep knowledge to correct the current Kaveri + 3) this be a "JV" (in short the foreign entity divulge their knowledge - tech and production). I just cannot see #2 happening. I very much doubt that GE and P&W share trade secrets between themselves.

I *think* the foreign entities are willing to replace parts of the Kaveri with products they have tested and produced. Reliable products - lowers their risks. But, even here, I very much doubt they will be willing to divulge production secrets. So, in this scenario, *as an example*, I would expect a Safran to provide components (hot section?), made in France, that can replace the current components within the Kaveri. They will test, certify, etc, but that is about it.

IMVVHO, India needs to fund the Kaveri with $1 billion a year, somewhere between 5-15 years to produce a reliable Kaveri (with the old specs). In addition India needs to fund a parallel effort, at teh same level, to produce a 110+ kN level engine. This parallel effort, I think, would take a longer time - 20 years or so.

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Re: Kaveri & aero-engine discussion

Postby nvishal » 06 Feb 2018 14:25

GoI going for 36 over the counter rafales was a strange decision

The French making the kaveri proposal to India(as an offset alternative) is also equally strange

The gossips begin here. Clearly, the MMRCA had a strange ending. Could anyone have predicated it would end like this?

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Re: Kaveri & aero-engine discussion

Postby chetak » 06 Feb 2018 15:44

NRao wrote:I *think* everything is going according to script.

I *think* India has proposed that the collab with a foreign entity 1) use the current Kaveri as the baseline + 2) that the foreign entity use their deep knowledge to correct the current Kaveri + 3) this be a "JV" (in short the foreign entity divulge their knowledge - tech and production). I just cannot see #2 happening. I very much doubt that GE and P&W share trade secrets between themselves.

I *think* the foreign entities are willing to replace parts of the Kaveri with products they have tested and produced. Reliable products - lowers their risks. But, even here, I very much doubt they will be willing to divulge production secrets. So, in this scenario, *as an example*, I would expect a Safran to provide components (hot section?), made in France, that can replace the current components within the Kaveri. They will test, certify, etc, but that is about it.

IMVVHO, India needs to fund the Kaveri with $1 billion a year, somewhere between 5-15 years to produce a reliable Kaveri (with the old specs). In addition India needs to fund a parallel effort, at teh same level, to produce a 110+ kN level engine. This parallel effort, I think, would take a longer time - 20 years or so.


our contracts are written and read by "scientists" while their contracts are written and also read by specialized, knowledgeable technically aware qualified lawyers. Its a no contest.

The goras will have plenty of inbuilt wiggle room to bamboozle us and also escape delivery of critical knowledge of vital parts ensuring that no secrets are passed on to us.

Of course, they will simply repurpose, scale up/down at minimal cost, already tested parts, to avoid expenditure and tell us that they have to spend billions in R&D to make specific parts for the kaveri.

We must fund and make them set up production facilities in India and ensure that our guys are trained as well as supervised during the production of 20-30 sets of each component before we accept the same.

Ensure through iron clad legal contracts with heavy punitive provisions so that such trained guys cannot leave the employment of the GoI for a good number of years.

We have had hundreds of guys jumping ship after expensive training, mostly abroad at the GoI cost.

I, once, spent 19 months, liaising with the state police, tracking, arresting and bringing back a rascal who jumped ship after training in germany. The cops literally begged me to get him arrested at only at his home and not in his new office where they were sure that he would cause a ruckus at work and precipitate a riot like situation.

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 11 Feb 2018 01:24

Got this via email. FWIW....

————————————————

As part of Rafale offsets, Safran is helping GTRE to make the Kaveri flyworthy. Serious work is now underway and there has been rumors that a Safranized Kaveri is already in France and is now undergoing bench testing. The plan here is to make the Kaveri meet the ASQR in terms of Wet Thrust, SFC (Specific Fuel Consumption), TSFC (Thrust-specific fuel consumption), etc by mating a variant of M88-4E core to the GTX-35 Kaveri. Now the M88 and Kaveri both have different dimensions especially the engine face diameter. As such the exact M88 core would be a bit small for the Kaveri and installing the same would result in a higher BPR (Bypass Ratio). It's not such a trivial thing to mate a core. But AFAIK the French have offered to install a modified M88 core and a lot has taken place after that offer including the rumors of Safranized Kaveri being bench tested.

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Re: Kaveri & aero-engine discussion

Postby ramana » 11 Feb 2018 04:14

Whats BPR?

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Re: Kaveri & aero-engine discussion

Postby Snehashis » 11 Feb 2018 04:28

ramana wrote:Whats BPR?


Bypass ratio.

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 11 Feb 2018 04:28

^^^^

Bypass ratio
https://en.wikipedia.org/wiki/Bypass_ratio

I will amend the post above to include that.

Add Later: Snehasis Saar, you beat me to it! :)

More verfication is need on the email above. All we can do is wait for info to come (on progress) via an official source - via Safran or GTRE.

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Re: Kaveri & aero-engine discussion

Postby ramana » 11 Feb 2018 05:15

So what will high BPR do to Hybrid Kaveri?

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 11 Feb 2018 05:57

^^^Higher the BPR, the greater the fuel consumption.

From the wiki link above, “Bypass provides a lower fuel consumption for the same thrust, measured as thrust specific fuel consumption (grams/second fuel per unit of thrust in kN using SI units)....Combat aircraft use engines with low bypass ratios to compromise between fuel economy and the requirements of combat: high power-to-weight ratios, supersonic performance, and the ability to use afterburners.”

Also from the wiki link above, “The normal definition for the bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core.

Again from the wiki link above....

- the M88 has a BPR of 0.30:1,
- the F404 has a BPR of 0.34:1
- the EJ200 has a BPR of is 0.4:1

Google Chacha says F414 has a BPR of 0.25:1

Kaveri - as per design specs - has a BPR of 0.16:1

But that cannot be verified, as Kaveri never flew.

BRF sorely lacks an engine guru to decipher all this.


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