GTRE Kaveri Engine

[Unnamed]

M88 is the best engine France has. Even EJ200 is the best engine of UK. Russia has sold Su35 with Al41F engine to China and is offering to India.

So, it is incorrect to say that no one gives the latest technology to others. They just don't give ToT of latest technology

You're partially correct. Let me explain that. France's best is M88 but Rafale F4 will have a better engine than the one they have now and that is being worked on right now. see, they are constantly working on it and releasing what they deem not harmful to themselves in the long run. See, my point is, France will offer the new M88 engine meant for F4 at a time when they will be working on their next generation of engines, they know they have something better than that with themselves. plus France does see India as a friendly country. not harmless, not neutral not potentially hostile, but friendly. international politics is the other hand of international arms/defence deals. no arms deal goes down without national, force level, international politics getting affected at the level it affects.

again russia is working on the completely new engine for their pakfa. that engine will have iterations of it. they will not even sell the originally designed engine when the pakfa is exported. they will get an export version of the engine ready for the standard export model and/or tweak the export version of the engine according to the customer's needs in the future. depending on things beyond technology, the sales terms will be determined. and usually economics and politics are the two main factors. just like in case of su-35s and china. will rusia sell the original pakfa engine to the chinese ? you can bet your sweet tushy that they won't, it will be an export version or if the chinese pay for it, anything in russian capablity what russia doesn't consider harmful to itself. russia won't, i repeat WILL NOT sell 6 squadrons of su35s armed and equipped better than their own su-35s. do you know why ? they share a border and are rivals in many levels.

"One of the reasons for China’s interest in the Su-35 is its AL-117S turbofan engine. Russia has repeatedly refused to sell the engine as a stand-alone product, which left the PLAAF with little choice but to acquire the entire aircraft. The Chinese military aviation industry is still struggling with designing and building an engine for its new fifth-generation stealth fighter prototype, the Chengdu J-20."

so, you see how engine technology is guarded safely ? russians are making the most out of an engine deal by selling an entire aircraft with an upgraded model of an older engine while they are designing a completely new engine themselves. Rest assured Kaveri is closely guarded. Only when we have something better than this Kaveri, will we export this shit, again to friendly countries only.

Forget ToT, the sales itself of the latest tech doesn't happen.

 

[Unnamed]

We (the french) were waiting your order ! never arrived...

But we cleared the way to accept israelis weapons so as to destroy Pak bunkers....

yes you did. thank you for that.

 

[Bon Plan]

yes you did. thank you for that.

There is a long friendship history between France and India.
It was a natural answer for us.
France and India have a similar view on most political problems. We are made to agree each other.

 

[Unnamed]

Are we so sure?
It's a clear and without any back thought question. Is the Safraniszd Kaveri built with M88 components ore not?

I really do not think that the M88 core Kevari is why we wanted SAFRAN to take a look at Kaveri. We have french as consultants to DRDO's lab GTRE. consultants don't manufacture subsystems. consultants don't manufacture nothing. what i think is, if the french team RECOMMENDS a M88 core'd Kaveri now, we will have a separate deal for it. after this certification. if it happens it is yet to come. and look what did the consultants said, the engine is good enough to fly as it is. so, the technical help with the problems did not happen pre audit.

We might get a derivative of the kaveri with an m88 core ready in time for integration with tejas, to meet the tejas production schedule which needs large numbers badly in the shortest possible time. it's an emergency that we find a workable solution with a mix and match of both the kabini core'd kaveri design and an M88 core. we are wasting money if we are not looking to solve problems with practical workable solutions available at your disposal. i agree fully.

doesn't mean we stop developing kabini on our own. we shouldn't. i hope so. really hope so.

 

[Unnamed]

There is a long friendship history between France and India.
It was a natural answer for us.
France and India have a similar view on most political problems. We are made to agree each other.

somehow i am not being able to click on the upvote icon. so here's to indo-french friendship. (for there's no beer here. )

 

[militarist]

Al41F which is the main component of the upgrade

In fact Super Sukhoi program does not imply the new engines at the moment, but there is a possibility of co-development of the new engine exclusively for Indian aircraft

 

[pachawry]

In fact Super Sukhoi program does not imply the new engines at the moment, but there is a possibility of co-development of the new engine exclusively for Indian aircraft

Su30 cant be super just by avionics upgrade. The main things involved are radar upgrade from BARS radar to Zhuk AESA radar and engine upgrade. Su30 avionics is in Indian hands already (earlier israeli ones have been replaced with SAMTEL-HAL). Airframe change is ruled out as that will require redesign. Even change of metal to composite will change centre of mass. So, the only reason India needs Russian involvement is to get the radar and engine.

Co-development is meaningless and serves no purpose. Most of teh engine components are easy to make. It is about 15% of the components that are critical and needs high end fine tuning and technology

 

[vstol Jockey]

I had written a few posts back that Kaveri engine weight has been reduced drastically and it is no more a 1235 kgs engine. I am posting the link to DRDO page and please read at the bottom.
The TWR is listed as 7.8 for a max thrust of 8260 kgs. this means 8260/7.8=1059 kgs. This makes this engine lighter and far superior to RD-33 and also f414. Its dry SFC is finest of any engine of its class today. Finally, if we take its ISA max thrustof 98KN as the bench mark, the TWR will be 10000/1059=9.44.
https://www.drdo.gov.in/drdo/English/index.jsp?pg=kaveri-new.jsp

 

[Milspec]

Please enlighten yourself with the M53 engine specs and you will realise that M2K goes easily with that engine with an MTOW of 17 tons. Once you do the exercise about Kaveri which I asked you to do, you will get many of your doubts cleared automatically.

Off topic , but how do you derate for both capacity and efficiency at altitude. Are there any standards or equations applicable?
Also how is the thrust measured, is it just by the EPR, or there is some seperate instrumentation for validating EPR calcs.

 

[vstol Jockey]

Off topic , but how do you derate for both capacity and efficiency at altitude. Are there any standards or equations applicable?
Also how is the thrust measured, is it just by the EPR, or there is some seperate instrumentation for validating EPR calcs.

EPR-Engine pressure ratio is one method and old method of setting and calculating thrust. Now the thrust is set using N1 RPM but the thrust continues to be measured by the ERR as it is a ratio of discharge pressure to inlet pressure. The Fan N1 rpm is set in percentages of its limiting RPM.
Derating as the term suggests is a method of reducing thrust when the better conditions exist and increasing the thrust when inferior conditions exist. You do this by varying the airflow or by varying the TET. Kaveri uses both to achieve variable cycle operation.
At low altitudes, the air density is low due to high temperatures and at high altitude the air density is low due to rarified atmosphere. And also as a combination of high temp and high altitude as is common in India during summers.
the air density effects the mass flow thru the engine and that results in altering the engine thrust.

 

[Milspec]

EPR-Engine pressure ratio is one method and old method of setting and calculating thrust. Now the thrust is set using N1 RPM but the thrust continues to be measured by the ERR as it is a ratio of discharge pressure to inlet pressure. The Fan N1 rpm is set in percentages of its limiting RPM.
Derating as the term suggests is a method of reducing thrust when the better conditions exist and increasing the thrust when inferior conditions exist. You do this by varying the airflow or by varying the TET. Kaveri uses both to achieve variable cycle operation.
At low altitudes, the air density is low due to high temperatures and at high altitude the air density is low due to rarified atmosphere. And also as a combination of high temp and high altitude as is common in India during summers.
the air density effects the mass flow thru the engine and that results in altering the engine thrust.

Thanks for response, will bug you little more.

I am guessing ERR is typo, so if I am reading correctly EPR being ratio of DP/inlet similar to compression ratios in compressors, but on the gauge do you still see Thrust as N1% or do your have both EPR and N1 readouts. Is N1 linear to EPR or does it have some funky curve specific to engines. Also are there any inlet side economizer setups to increase compression ratios? also will be helpful if you have some low load efficiency optimization reading material. thanks in advance.

About the spec calculation , I am guessing that thrust is calculated at sealevel and a correction factor equation used to correct to the barometric pressure that corresponds to the altitude. How closely does the correction factor align with actual N1 thrust in flight conditions?

 

[vstol Jockey]

I am guessing ERR is typo, so if I am reading correctly EPR being ratio of DP/inlet similar to compression ratios in compressors, but on the gauge do you still see Thrust as N1% or do your have both EPR and N1 readouts. Is N1 linear to EPR or does it have some funky curve specific to engines. Also are there any inlet side economizer setups to increase compression ratios? also will be helpful if you have some low load efficiency optimization reading material. thanks in advance.

In old B737-200 engines, the trust was set using EPR as they were turbojet engines. But for turbofan engines the thrust is usually set based on N1 which is the fan rotation speed and dependent totally on the airflow passing thru it. Higher the airflow, higher will be the speed and so they are inefficient at low speeds and for this reason the geared fans were introduced. EPR is actual difference the pressures of the exhaust pressure and HP compressor pressure. It is a more efficient way of calculating thrust. But a bit complicated. N1 is easy.

About the spec calculation , I am guessing that thrust is calculated at sealevel and a correction factor equation used to correct to the barometric pressure that corresponds to the altitude. How closely does the correction factor align with actual N1 thrust in flight conditions?

Yes that is how it is done. You calculate the engine thrust for a specific condition and than use standard calculations to draw graphs and tha again cross check with actual performance in those conditions in various flight profiles. A jet engine always produces more thrust at arounf mach 0.4-0.5 conditions due to ram rise. It is for this reason that the thrust specified is always called sea level static thrust. this thrust further reduces due to offtake of bleed air and driving the gear box for auxiliary services.

 

[pachawry]

I had written a few posts back that Kaveri engine weight has been reduced drastically and it is no more a 1235 kgs engine. I am posting the link to DRDO page and please read at the bottom.
The TWR is listed as 7.8 for a max thrust of 8260 kgs. this means 8260/7.8=1059 kgs. This makes this engine lighter and far superior to RD-33 and also f414. Its dry SFC is finest of any engine of its class today. Finally, if we take its ISA max thrustof 98KN as the bench mark, the TWR will be 10000/1059=9.44.
https://www.drdo.gov.in/drdo/English/index.jsp?pg=kaveri-new.jsp

The bypass ratio of 0.16 is really a surprise. It is too low and will need to be increased to 0.3 to 0.4 for it to become fuel efficient Turbofan. Currently it ia leaky turbojet

 

[vstol Jockey]

The bypass ratio of 0.16 is really a surprise. It is too low and will need to be increased to 0.3 to 0.4 for it to become fuel efficient Turbofan. Currently it ia leaky turbojet

But the fact is that even with this ratio, the engine has an SFC of 0.78kg/hr/kg giving it a max fuel burn of about 4.13 tond at sea level at max dry power while f414 and M88 both have poor SFC compared to kaveri.

 

[Milspec]

In old B737-200 engines, the trust was set using EPR as they were turbojet engines. But for turbofan engines the thrust is usually set based on N1 which is the fan rotation speed and dependent totally on the airflow passing thru it. Higher the airflow, higher will be the speed and so they are inefficient at low speeds and for this reason the geared fans were introduced. EPR is actual difference the pressures of the exhaust pressure and HP compressor pressure. It is a more efficient way of calculating thrust. But a bit complicated. N1 is easy.


Yes that is how it is done. You calculate the engine thrust for a specific condition and than use standard calculations to draw graphs and tha again cross check with actual performance in those conditions in various flight profiles. A jet engine always produces more thrust at arounf mach 0.4-0.5 conditions due to ram rise. It is for this reason that the thrust specified is always called sea level static thrust. this thrust further reduces due to offtake of bleed air and driving the gear box for auxiliary services.

Last question, how is Suction pressure and Discharge pressure measured, is it a differential pressure transducer or a two absolute pressure transducer and both correlated to barometric pressure. thanks again!

 

[vstol Jockey]

Last question, how is Suction pressure and Discharge pressure measured, is it a differential pressure transducer or a two absolute pressure transducer and both correlated to barometric pressure. thanks again!

For efficient and safe running of engine, we need to monitor pressure and temp all along the engine air flow. Most of this data is used by Fadec to set and monitor other parameters of th engine. Like moving the inlet guide vanes, controlling fuel flow, afterburners and prevention of engine surge by regulating acceleration and deceleration.
You must have seen a vertical tube like structure hanging ahead of the engine face.

This is called the combined TAT and Pressure probe. This measures the ambient temp and press as it exists before entering the engine. this is a very important parameter as the altitude and temp variations are recorded and used by the engine control system w.r.t this probe. This is called PT-1 probe.
Now as the air goes thru the fan, it is compressed and as a result the temp rises. remember the gas equation which you learnt in 11th standard.
This fan discharge pressure is measured at the HP compressor face by a probe called PT-2. A part of air is bypassed at this stage from fan and part of it enters the HP compressor. This air entering the compressor is further compressed and its temp rises. we all know that Mass/volume = density or Mass=volumexdensity. The engine has very small volume of combustion chamber so to increase the mass flow for the limited volume of the combustion chamber, the density must rise by compressing the air. we also know P1V1/T1=P2V2/T2 from gas equations. if you vary any one parameter, other parameters will undergo a change to compensate for it so as to keep the parameters final count constant.
The probe which measure the compressor discharge pressure and temp is called PT-3 and the fuel flow and throttle demands are controlled thru this probe and the last two probes in the system to prevent engine surge/stalling.
The combustion chamber imparts more energy to the airflow and expands its volume which is used by HP turbine to drive HP compressor and provide propulsion to the engine. Thisis measured by PT-4, PT-5 is behind the LP turbine, PT-6 at the afterburner stage on the jet pire and PT-7 is at the end where Nozzle discharge pressure is measured alongwith exhaust gas temp called EGT.
The PT-3 and PT-7 are used for determining the EPR and these are two most imp probes for setting thrust and controlling engine RPM.
These probes are nearly identical to the ones used in flight instruments for measuring IAS and made of either thermocouples or bowmen's tubes or combination of both.

 

[Milspec]

For efficient and safe running of engine, we need to monitor pressure and temp all along the engine air flow. Most of this data is used by Fadec to set and monitor other parameters of th engine. Like moving the inlet guide vanes, controlling fuel flow, afterburners and prevention of engine surge by regulating acceleration and deceleration.
You must have seen a vertical tube like structure hanging ahead of the engine face.
View attachment 2767
This is called the combined TAT and Pressure probe. This measures the ambient temp and press as it exists before entering the engine. this is a very important parameter as the altitude and temp variations are recorded and used by the engine control system w.r.t this probe. This is called PT-1 probe.
Now as the air goes thru the fan, it is compressed and as a result the temp rises. remember the gas equation which you learnt in 11th standard.
This fan discharge pressure is measured at the HP compressor face by a probe called PT-2. A part of air is bypassed at this stage from fan and part of it enters the HP compressor. This air entering the compressor is further compressed and its temp rises. we all know that Mass/volume = density or Mass=volumexdensity. The engine has very small volume of combustion chamber so to increase the mass flow for the limited volume of the combustion chamber, the density must rise by compressing the air. we also know P1V1/T1=P2V2/T2 from gas equations. if you vary any one parameter, other parameters will undergo a change to compensate for it so as to keep the parameters final count constant.
The probe which measure the compressor discharge pressure and temp is called PT-3 and the fuel flow and throttle demands are controlled thru this probe and the last two probes in the system to prevent engine surge/stalling.
The combustion chamber imparts more energy to the airflow and expands its volume which is used by HP turbine to drive HP compressor and provide propulsion to the engine. Thisis measured by PT-4, PT-5 is behind the LP turbine, PT-6 at the afterburner stage on the jet pire and PT-7 is at the end where Nozzle discharge pressure is measured alongwith exhaust gas temp called EGT.
The PT-3 and PT-7 are used for determining the EPR and these are two most imp probes for setting thrust and controlling engine RPM.
These probes are nearly identical to the ones used in flight instruments for measuring IAS and made of either thermocouples or bowmen's tubes or combination of both.

Thanks for that, readup on TAT probes, calibration would be very interesting. As always Thanks for the info again

 

[vstol Jockey]

Thanks for that, readup on TAT probes, calibration would be very interesting. As always Thanks for the info again

You can always trust me for best knowledge about jet engines and aerodynamics. Till date no one in armed forces has been able to challenge me on these topics but I am not a certified engineer. So an Engineer will always be better than me on these topics.
FYI, my daughter is going up for front gun firing from Do-228 aircraft of ICG. I taught her the complete science abt it. From aiming to trignomyiry involved and how it is very difficult to hit targets at sea compared to those on shore. I taught her about angles and bullet velocity and across and along corrections. She went and told someone in her sqn abt what I taught her when she was here after my fathers death. She has now been asked by her sqn to explain what she has learnt from me and I am making a PPT for her to do the presentation. Aisa bhi hota hai.
I am known within IN as best in air to ground weapon delivery and also winner of Easterrn air command trophy in air to ground weapon delivery while being a part of 20sqn IAF. I also won the Top Gun medal during training as part of 141 PC.

 

[lcafanboy]

GTRE has issued a tender for 'Expression of Interest for Altitude Tests of Kaveri Engine and its Derivative', bid opening on 1st Aug 18

Dimensions & details of Engine as per EOI document
Inlet Dia : 749mm
Max Dia : 940mm
Length : 3900mm

LP Comp - Three stage
HP Comp - Six stage
HP Turbine - single stage & cooled
LP Turbine - single stage
Main Combustion Chamber - annular direct flow
Afterburner system with axi-symmetric exhaust nozzle
The engine has a Kaveri full Authority Digital Engine Control System (KADECS)

Kaveri is of following performance class at Indian Standard Atmosphere (ISA) Sea level Static (SLS)

Dry Thrust 52 kN
Dry SFC 0.78 kg/kgf/hr
Dry air flow 77.8 kg/sec
Reheat Thrust 81 kN
Reheat SFC 2.03 kg/kgf/hr
Reheat air flow 77.8 kg/sec

Tests to be conducted in two phases in next 3 years Phase 1 AT-1 75 hrs Phase 2 AT-2 100 hrs

 

[TARGET]

GTRE has issued a tender for 'Expression of Interest for Altitude Tests of Kaveri Engine and its Derivative', bid opening on 1st Aug 18

Dimensions & details of Engine as per EOI document
Inlet Dia : 749mm
Max Dia : 940mm
Length : 3900mm

LP Comp - Three stage
HP Comp - Six stage
HP Turbine - single stage & cooled
LP Turbine - single stage
Main Combustion Chamber - annular direct flow
Afterburner system with axi-symmetric exhaust nozzle
The engine has a Kaveri full Authority Digital Engine Control System (KADECS)

Kaveri is of following performance class at Indian Standard Atmosphere (ISA) Sea level Static (SLS)

Dry Thrust 52 kN
Dry SFC 0.78 kg/kgf/hr
Dry air flow 77.8 kg/sec
Reheat Thrust 81 kN
Reheat SFC 2.03 kg/kgf/hr
Reheat air flow 77.8 kg/sec

Tests to be conducted in two phases in next 3 years Phase 1 AT-1 75 hrs Phase 2 AT-2 100 hrs

What they are asking here ? Do they need testers or private testing institute who will do it for them .