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Kaveri & aero-engine discussion

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Re: Kaveri & aero-engine discussion

Postby Indranil » 28 Feb 2017 03:57

Rishi Verma wrote:I know what I am talking about.

Good that you let us know. Otherwise, how would we have known?

Rishi Verma wrote:Kaveri-2 with snecma input doesn't even exist yet. The kaveri-1 data is no use for the future test flight.

You are right. How is Kaveri-1 data useful for Kaveri-2? Just like how is 404 data relevant to the 414?

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Re: Kaveri & aero-engine discussion

Postby Indranil » 28 Feb 2017 04:04

shiv wrote:
Zynda wrote:^^Do you mean that one prototype of Kaveri has been tested for 2500 hours spreading over various test coupons with no changes in between? Or one engine has been run continuously for 2500 hours in one go?

Edit: If its the latter, perhaps it could be accelerated testing worth 2500 hours?

Run continuously is what the guy in the Kaveri section told me. And still running. But I was so full of questions that long after I left the hall I did a facepalm and thought "Duh! I should have asked him more about this". They have built 8-9 engines IIRC (Can't recall the exact number)

Hakeem, that's not possible. They have run 2500 hours of testing on one prototype engine. Kaveri still has a long way to go. There are a set of very knowledgeable SDREs in GTRE. Unfortunately none of them with main decision making power. One thing which has worked out well is that this govt. knows that money has to be poured into this project to get it up and running.

Snehashis wrote:It's probably the Kaveri Marine KGMT. There was talk to 5000-6000 hours of continuous test required to fit into a warship. IIRC Atleast one R class destroyer will be re-engined with KGMT.

User spec has changed. Navy and GTRE are trying to find a way forward. The user is willing.

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Re: Kaveri & aero-engine discussion

Postby shiv » 28 Feb 2017 07:31

Zynda wrote:So it seems like GTRE have been running the engine continuously for 3.5 months. Like you said, a few questions immediately comes to my mind. For which conditions are they running the engines? i.e mission profiles? Are they running the engine mimicking real life take-off to landing (manoeuvres included in mission profiles)? Or are they running it continuously at a specified thrust rating? Perhaps JayS can shed some light.

Edit: It seems like GTRE wants to do test & check fatigue performance of the article in real time instead of accelerated time scales. Good for them.

These are the types of questions that came to my mind after I rested my ass on a bus seat outside the venue after 7 hours on my feet - at which time my brain suddenly switched itself back on. There must be a switch there. But I do know that other phoren engines are run continuously by their manufacturers for thousands of hours (recall reading that elsewhere) to check component reliability, wear and tear. The guy did say they have made 8 or 9 engines and one is running continuously. That's a lot of aviation fuel was the only thought that came up, but only a fraction of what the IAF or an airline would use up in a day.

I was wondering if, in the morning, the boss comes up and says "Chalo ab isko zor se ghumao" and turns up the throttle with an evil grin. Or whether they just run the thing at constant RPM so chana can be roasted in the exhaust for snack time

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Re: Kaveri & aero-engine discussion

Postby Cybaru » 28 Feb 2017 12:16

Rishi Verma wrote:I know what I am talking about. Kaveri-2 with snecma input doesn't even exist yet. The kaveri-1 data is no use for the future test flight.


I have seen many a folk use this technique to get a leg up and not question what they write. They *HINT* armed forces background or whatever. If you are armed forces, please say so and don't hide behind such hints.

I applaud Deejay for sharing his background so that we can understand where he is coming from and understand his point of view. It helps immensely in a discussion.

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Re: Kaveri & aero-engine discussion

Postby Rishi Verma » 28 Feb 2017 14:27

Indranil wrote:
Rishi Verma wrote:I know what I am talking about.

Good that you let us know. Otherwise, how would we have known


Hi Indranil,
What's the purpose of taking a statement out of context which wasn't even directed towards you? I didn't expect it from you.

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Re: Kaveri & aero-engine discussion

Postby Gyan » 28 Feb 2017 17:55

https://4.bp.blogspot.com/-Zc5L7fLoaYk/ ... Poster.JPG

This is pic of brochure posted on Trishul Blog. Does it give more info to add to our knowledge base? IIRC the LP stage had given problems in flying test bed tests of Kaveri.

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Re: Kaveri & aero-engine discussion

Postby JayS » 28 Feb 2017 18:46

Rishi Verma wrote:I know what I am talking about. Kaveri-2 with snecma input doesn't even exist yet. The kaveri-1 data is no use for the future test flight.


OK Sir, please tell us then what exactly is the difference in the so-called Kaveri-2 and Kaveri-1. What is the basis on which you say existing flight test data is "of no use" in future flight testing...? What input Snecma is giving for Kaveri exactly..?

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Re: Kaveri & aero-engine discussion

Postby JTull » 28 Feb 2017 19:02

shiv wrote:I was wondering if, in the morning, the boss comes up and says "Chalo ab isko zor se ghumao" and turns up the throttle with an evil grin. Or whether they just run the thing at constant RPM so chana can be roasted in the exhaust for snack time


I'm glad GTRE are not sitting on their bums and waiting for some gora to save them. They must have institutional knowledge of what data needs to be gathered and this must surely go beyond a headline thrust number. These bench tests will allow it to model potential impact of any design changes to various parts of such a complex system. More data they have the better it is.

I was once being shown around a company having hydrogen fuel cells. These can be tiny (about the size of a AAA battery) but could be stacked up in 3 dimensions, 100 times in size - maybe more. Despite having a ready product, their lab had hundreds of them being run continuously but with many other variable parameters, such as different ambient temperatures, constant power but at different levels, variable power, etc.

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Re: Kaveri & aero-engine discussion

Postby Indranil » 28 Feb 2017 20:50

Rishi Verma wrote:Hi Indranil,
What's the purpose of taking a statement out of context which wasn't even directed towards you? I didn't expect it from you.

I did not enjoy writing it one bit either. But, post after posts of yours in the last page and in LCA thread forced me to.

I know that you didn't like my criticism, but by that same token, don't you find it distasteful to deride the work of tens of thousands of employees with blanket statements? And then you say you know it all.

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Re: Kaveri & aero-engine discussion

Postby NRao » 28 Feb 2017 20:52

I do NOT think either the Snecma/Safran nor the GE (F414-INS6 enhancement for the AMCA) will provide India with anything more than a snapshot of an engine. Based on these two "engine"s, I very much doubt that India will be able to design AND productize the next gen engine.

Having said that, I think, both are good efforts to provide a much needed breathing space to their respective projects.

As a student, way back, I had a close friend (Indian) who was completing his Ph.D in material science (I had not clue it even existed until I met this guy). Back then there were no laptops and certainly no "spreadsheet"s. All data that was collected was written on paper, then types (manual type writers, with ribbons that faded). To create a "table" we had to use ----- to mark rows and | to mark columns. And we had liquid paper to correct our typing mistakes. This h=guy - in the 70s - had at least a 100 (single sided) pages of data (took years to collect) - explaining what all that was additional pages.

For India, to become a power in the area of engines, will need some 1000 such guys. MOST of them will fail, but will contribute to the base knowledge. Need to fund this controlled madness.

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Re: Kaveri & aero-engine discussion

Postby Rishi Verma » 01 Mar 2017 00:28

Indranil wrote:
Rishi Verma wrote:Hi Indranil,
What's the purpose of taking a statement out of context which wasn't even directed towards you? I didn't expect it from you.

I did not enjoy writing it one bit either. But, post after posts of yours in the last page and in LCA thread forced me to.

I know that you didn't like my criticism, but by that same token, don't you find it distasteful to deride the work of tens of thousands of employees with blanket statements? And then you say you know it all.


Boss, yes I am pessimistic about the manufacturability of the LCA and you are welcome to meet people in the IAF and hear them say why they have no faith in stated deadlines or plans. But the context of my present post was anything but "deriding". I was suggesting why kaveri would not need an imported flying test-vehicle. But anyway...

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Re: Kaveri & aero-engine discussion

Postby Indranil » 01 Mar 2017 00:44

Then you don't have the same yardstick of derision for yourself and others. By the way, please don't presume that because I support the desi products vociferously, that I don't talk to or agree with IAF personnel. But, I am not an yes-man to either groups.

This is the last of this OT from me. You can have the last word if you want to.

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Re: Kaveri & aero-engine discussion

Postby ragupta » 01 Mar 2017 00:45

Pessimist can hold on to it. India needs to make sure the optimistics keep working and I believe they will make it happen.

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Re: Kaveri & aero-engine discussion

Postby JayS » 02 Mar 2017 16:01

JayS wrote:
Rishi Verma wrote:I know what I am talking about. Kaveri-2 with snecma input doesn't even exist yet. The kaveri-1 data is no use for the future test flight.


OK Sir, please tell us then what exactly is the difference in the so-called Kaveri-2 and Kaveri-1. What is the basis on which you say existing flight test data is "of no use" in future flight testing...? What input Snecma is giving for Kaveri exactly..?


Still waiting for answer...kindly enlighten us please.

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Re: Kaveri & aero-engine discussion

Postby Rishi Verma » 02 Mar 2017 17:40

JayS wrote:
JayS wrote:
OK Sir, please tell us then what exactly is the difference in the so-called Kaveri-2 and Kaveri-1. What is the basis on which you say existing flight test data is "of no use" in future flight testing...? What input Snecma is giving for Kaveri exactly..?


Still waiting for answer...kindly enlighten us please.


You already know then why ask. One that was tested in Russia I call k-1. One that "may" get "improved" with French help, one that "may" get production ready, one that "may" find design win with AMCA I call K-2.

My point was when and if the K-2 materializes then it won't be necessary to test it on a foreign land on a foreign aircraft.

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Re: Kaveri & aero-engine discussion

Postby JayS » 02 Mar 2017 19:29

Rishi Verma wrote:
JayS wrote:
Still waiting for answer...kindly enlighten us please.


You already know then why ask. One that was tested in Russia I call k-1. One that "may" get "improved" with French help, one that "may" get production ready, one that "may" find design win with AMCA I call K-2.

My point was when and if the K-2 materializes then it won't be necessary to test it on a foreign land on a foreign aircraft.


I don't know. I was hoping you would tell me, why the test data from "K-1" is not useful for "K-2". And to justify this statement, I hope you would tell us what exactly are the changes from K-1 to K-2 which make the test data from K-1 redundant.

I forgot to ask this to GTRE folks in AI-2017. So if you could tell me I would be grateful. Unless one knew what exactly Snecma would tinker with in K-1, how would one can say with confidence that the existing test data won't not useful anymore. I am looking forward, since you seems to know exact answers to what I seek. Humble request wonly.

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Re: Kaveri & aero-engine discussion

Postby JayS » 02 Mar 2017 19:46

https://twitter.com/delhidefence/status ... 3096198144

Here's a picture of the MANIK small turbofan engine suitable fro cruise missile applications on a GTRE test-bed. Courtesy @DRDO_India


Image

I am told in AI-2017 by a GTRE guy when I asked if its the same engine as Laghushakti or something different - This engine "Small Turbofan Engine" was first dubbed as "Laghushakti". But later they changed the name to Manik in the honour of Dr K Tamilmani. Dunno if its true or not.

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Re: Kaveri & aero-engine discussion

Postby Rishi Verma » 02 Mar 2017 21:01

JayS wrote:
Rishi Verma wrote:
You already know then why ask. One that was tested in Russia I call k-1. One that "may" get "improved" with French help, one that "may" get production ready, one that "may" find design win with AMCA I call K-2.

My point was when and if the K-2 materializes then it won't be necessary to test it on a foreign land on a foreign aircraft.


I don't know. I was hoping you would tell me, why the test data from "K-1" is not useful for "K-2". And to justify this statement, I hope you would tell us what exactly are the changes from K-1 to K-2 which make the test data from K-1 redundant.

I forgot to ask this to GTRE folks in AI-2017. So if you could tell me I would be grateful. Unless one knew what exactly Snecma would tinker with in K-1, how would one can say with confidence that the existing test data won't not useful anymore. I am looking forward, since you seems to know exact answers to what I seek. Humble request wonly.


Since you requested so humbly:

The test data is on a pendrive at Koramangala ram mandir near a paanwala shop in an encrypted PDF format. Please go there on Saturday with a coconut in your right hand and recite Hanuman Chalisa 108 times. The priest will give you the pen drive. If the priest breaks the coconut that means you didn't convince him and you should leave the premises asap.

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Re: Kaveri & aero-engine discussion

Postby Karan M » 02 Mar 2017 21:12

Why don't you answer his query.

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Re: Kaveri & aero-engine discussion

Postby Cybaru » 02 Mar 2017 22:14

Because its easier to hint/claim to be inside person/armed forces and keep that gray zone going to create/distinguish onself from other posters and hog the limelight.

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 02 Mar 2017 23:30

egxactly! :D bakwas kar raha hai!!

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Re: Kaveri & aero-engine discussion

Postby JayS » 02 Mar 2017 23:51

Rishi Verma wrote:
JayS wrote:
I don't know. I was hoping you would tell me, why the test data from "K-1" is not useful for "K-2". And to justify this statement, I hope you would tell us what exactly are the changes from K-1 to K-2 which make the test data from K-1 redundant.

I forgot to ask this to GTRE folks in AI-2017. So if you could tell me I would be grateful. Unless one knew what exactly Snecma would tinker with in K-1, how would one can say with confidence that the existing test data won't not useful anymore. I am looking forward, since you seems to know exact answers to what I seek. Humble request wonly.


Since you requested so humbly:

The test data is on a pendrive at Koramangala ram mandir near a paanwala shop in an encrypted PDF format. Please go there on Saturday with a coconut in your right hand and recite Hanuman Chalisa 108 times. The priest will give you the pen drive. If the priest breaks the coconut that means you didn't convince him and you should leave the premises asap.


If only I knew Hanuman Chalisa or Ram Raksha. Alas..! But you seem to know all that evil yindoo stuff and must have got the pendrive by convincing the priest already (or you are the priest himself for all I know). So please be kind and let us know what you know (you said you know what you are talking about, didn't you..??) from that pendrive about K-1 and K-2. What is the difference between the two exactly which renders test data of K-1 so useless.

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Re: Kaveri & aero-engine discussion

Postby ramana » 02 Mar 2017 23:51

My take.

Kaveri -!(the one that was tested in Russia) has noise at high rpm per DRDO chief Dr. Christopher.
To me this indicates turbine blade vibrations at high speed.
This means a blade stiffness issue.
You can either increase stiffness or reduce mass to get above the resonant frequency.

All this would need new test data.
So K-1 test data is interesting but not wholly germane to the K-2 after blade fix.

Anyway Dr. Christopher is confident it will be solved in a couple of years and will fly in an LCA.
He must have good basis for his confidence.
We have waited for so long and a wait of two more years wont affect our sanguinity.

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Re: Kaveri & aero-engine discussion

Postby NRao » 02 Mar 2017 23:59

Anyway Dr. Christopher is confident it will be solved in a couple of years


So, why is France spending $1 billion - as offset for the Rafale deal?

And, are these two different/separate efforts? IF they are then both expect to have an engine that can be matted with the LCA?

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Re: Kaveri & aero-engine discussion

Postby JayS » 03 Mar 2017 00:38

ramana wrote:My take.

Kaveri -!(the one that was tested in Russia) has noise at high rpm per DRDO chief Dr. Christopher.
To me this indicates turbine blade vibrations at high speed.
This means a blade stiffness issue.
You can either increase stiffness or reduce mass to get above the resonant frequency.

All this would need new test data.
So K-1 test data is interesting but not wholly germane to the K-2 after blade fix.

Anyway Dr. Christopher is confident it will be solved in a couple of years and will fly in an LCA.
He must have good basis for his confidence.
We have waited for so long and a wait of two more years wont affect our sanguinity.


Flutter in the booster stages (low pressure compressor). It happens only on certain points - at altitudes (my guess) and at high power op points (Dr Christopher). I am told GTRE resolved this issue already. They claimed they can fly it in LCA without help from Snecma. Take this one FWIW though.

Here is what we know already. Kabini core works well, as expected. How we can conclude this?? Kaveri has achieved targeted dry trust. There has been no dispute on this, reported anywhere that I have seen. UCAV program was linked to Kabini since quite a few years. They would not have done it without good confidence over Kabini's performance. Also Kaveri performed rather well in Marine avatar KGMT. This also indicates that the issue with flutter is at higher altitude point (amd thus it was uncovered only during flight testing in Russia. If only we atleast had our own High altitude test facility this problem could have been seen much earlier). The shortfall in wet thrust was due to AB performance. It has screech issue as well. (Now GTRE claim they have overcome this issue as well). From all the info I have seen, the problems are/were only for the LPC and AB.

Adding to this, French reviewed Kaveri and concluded about 20% work is remaining to make it flight-worthy. The ground tests, high speed taxi tests and actual flight tests itself is a huge task and I suspect it constitutes major portion on this 20% remaining tasks. Connecting the dots, I think, there is not much to be rectified in Kaveri. All measure issues must have been taken care of already. If there was any issue with the Kabini or major redesign on LPC/AB was needed, there is no way any one in the work can make Kaveri flight worthy in 2years. And there is no question of replacing Kaveri core with M88 core, since you can't just take one core and stick it to another engine's LP system without good 4-5yrs of work on it. I initially thought Scecma might do this but after some pondering and adding 2+2, I came to conclusion that there seems to be no reason why Kabini be replaced at all.

Even if we choose not to believe GTRE's claim that the design thrust for dry as well as wet conditions has been achieved already, still from the estimations/timelines/budgets given by Snecma, there seems to be no major technical issue to be resolved. Its mainly to add finishing touches, plucking some low hanging fruits and complete the rest of the test program.

JMT.

BTW another tidbit for jingos - currently Kaveri's stall margin is 19-20% as against design target of 22% while GTRE wants to achieve 25%. This is one thing yet to be achieved, they said in AeroIndia.

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Re: Kaveri & aero-engine discussion

Postby Indranil » 03 Mar 2017 00:45

Rakesh wrote:egxactly! :D bakwas kar raha hai!!

Cybaru wrote:Because its easier to hint/claim to be inside person/armed forces and keep that gray zone going to create/distinguish onself from other posters and hog the limelight.

There is no need for this.

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Re: Kaveri & aero-engine discussion

Postby Rakesh » 03 Mar 2017 00:55

Sorry Saar. No more.

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Re: Kaveri & aero-engine discussion

Postby Cybaru » 03 Mar 2017 00:57

Fair enough Indranil, but please do call out posters who hint about some connection or inside knowledge to create a sense of authenticity where really none exists. I think we on BR treat almost everyone civilly so there is no need to do that on their part.

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Re: Kaveri & aero-engine discussion

Postby Neela » 03 Mar 2017 01:37

Indranil
You had posted a table in blue font with Kaveri engines K5..K9 with details about the engine run times.
Forum search engine wouldn't let me search anything with less than 3 characters.
Im trying to see if info collected at AeroIndia2017 is newer than the table you posted.

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Re: Kaveri & aero-engine discussion

Postby ramana » 03 Mar 2017 01:55

JayS, The search for realizing Kaveri is like Sagara's sons quest to realize the other great river Ganga. So many careers ended in the quest.

Now looks like Bhagirathi is about to emerge.
Lets hope Dr. Christopher is right and wish the team well.

Lesson don't name projects after Rivers!!!!
In IITM, the buses were named after mountains and hostels after rivers.
Go figure.

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Re: Kaveri & aero-engine discussion

Postby disha » 03 Mar 2017 03:01

^^ So that buses arrive on time and hostels do not move away ...

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Re: Kaveri & aero-engine discussion

Postby shiv » 03 Mar 2017 06:31

JayS wrote:BTW another tidbit for jingos - currently Kaveri's stall margin is 19-20% as against design target of 22% while GTRE wants to achieve 25%. This is one thing yet to be achieved, they said in AeroIndia.

What eej stall margin?

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Re: Kaveri & aero-engine discussion

Postby nachiket » 03 Mar 2017 07:18

shiv wrote:
JayS wrote:BTW another tidbit for jingos - currently Kaveri's stall margin is 19-20% as against design target of 22% while GTRE wants to achieve 25%. This is one thing yet to be achieved, they said in AeroIndia.

What eej stall margin?

From wiki aunty:

A compressor will only pump air in a stable manner up to a certain pressure ratio. Beyond this value the flow will break down and become unstable. This occurs at what is known as the surge line on a compressor map. The complete engine is designed to keep the compressor operating a small distance below the surge pressure ratio on what is known as the operating line on a compressor map. The distance between the 2 lines is known as the surge margin on a compressor map. Various things can occur during the operation of the engine to lower the surge pressure ratio or raise the operating pressure ratio. When the 2 coincide there is no longer any surge margin and a compressor stage can stall or the complete compressor can surge as explained in preceding sections.


Last line is what happened in Fl.Lt. Nachiketa's Mig-27 due to gun-gas ingestion leading to engine flameout I believe.

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Re: Kaveri & aero-engine discussion

Postby JayS » 03 Mar 2017 09:41

shiv wrote:
JayS wrote:BTW another tidbit for jingos - currently Kaveri's stall margin is 19-20% as against design target of 22% while GTRE wants to achieve 25%. This is one thing yet to be achieved, they said in AeroIndia.

What eej stall margin?


To add to Nachiket's post above, higher the stall margin, more the freedom you have throwing around your fighter without having to worry about stalling the engine at awkward angles when the engine is starving of incoming air.

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Re: Kaveri & aero-engine discussion

Postby Indranil » 03 Mar 2017 12:25

^^^ learned something new. Thank you boys.

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Re: Kaveri & aero-engine discussion

Postby Neela » 03 Mar 2017 12:35

Are these possible events that can influence surge margin?
Air pockets/High AoA/a bird hit ?

And design of intakes, fan , LP and HP compressor all influence the surge margin?
How the hell do they test the engine for all these conditions. It must be one mid boggling test envelope.

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Re: Kaveri & aero-engine discussion

Postby nachiket » 04 Mar 2017 05:35

Neela wrote:And design of intakes, fan , LP and HP compressor all influence the surge margin?
How the hell do they test the engine for all these conditions. It must be one mid boggling test envelope.

Of course. That is why there are so few modern jet engine manufacturers in the world and why the technology and the test data is so zealously guarded. And why claims of ToT from Snecma etc. sound like a joke.

Also goes to show how important it is for GTRE to have all required test facilities in house, like some posters mentioned earlier.

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Re: Kaveri & aero-engine discussion

Postby srin » 04 Mar 2017 05:59

JayS wrote:
Adding to this, French reviewed Kaveri and concluded about 20% work is remaining to make it flight-worthy. The ground tests, high speed taxi tests and actual flight tests itself is a huge task and I suspect it constitutes major portion on this 20% remaining tasks. Connecting the dots, I think, there is not much to be rectified in Kaveri. All measure issues must have been taken care of already. If there was any issue with the Kabini or major redesign on LPC/AB was needed, there is no way any one in the work can make Kaveri flight worthy in 2years. And there is no question of replacing Kaveri core with M88 core, since you can't just take one core and stick it to another engine's LP system without good 4-5yrs of work on it. I initially thought Scecma might do this but after some pondering and adding 2+2, I came to conclusion that there seems to be no reason why Kabini be replaced at all.


If you watch the Aero India press conference with MP, he said something to the effect of it will be based on M-83 (I presume he meant M-88). Since I don't understand anything about engines, I'm not too sure which technologies and to which part of the engine that French will contribute

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Re: Kaveri & aero-engine discussion

Postby shiv » 04 Mar 2017 07:35

Please pardon my posting this video here. It is a (very good and well explained) jet engine primer and might be the best way for people to get familiar with issues
https://youtu.be/n1QEj09Pe6k

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Re: Kaveri & aero-engine discussion

Postby Cybaru » 04 Mar 2017 08:44

Thanks Shiv! That was a wonderful primer on engines. The last line although not relevant for this thread was very insightful as well "The barrier to travel for most people is cost and not speed! Time is the enemy of privileged few and cost the enemy of the masses!"


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