I don't understand the point in wasting money by putting 90KN. F404 after 10 yrs should be replaced by phase-2 Kaveri, acc. to Aashish simulation shown its way more economical than 90KN. Kaveri may take 4-5yrs to be mature enough for production.
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I don't understand the point in wasting money by putting 90KN. F404 after 10 yrs should be replaced by phase-2 Kaveri, acc. to Aashish simulation shown its way more economical than 90KN. Kaveri may take 4-5yrs to be mature enough for production.
LCA Mk1A needs a minimum 60/95KN thrust engine. But my point was instead of going for 65/98kN as has been suggested as the initial rating for certification, let us go for 72/110KN straight away and use the engine with derate for LCA MK1A. That will help increase the hot core section life.
What is this safranised Kaveri? I see that GTRE has explicitly rejected any such ideas of importing cores as Core is the main technology. Jet engine program was not meant to be cost cutting program. It is an indigenous engine program with explicit intention to make the core of the engine.
Also, with the experience gained from past 20 years, manufacturing of Al31 in HAL Koraput why would one even think of M88 core? Why have such mentality that India is filled with incompetent people who won't be able to make an engine?
China have already made WS 10 engine and WS15 engine by 2010-15. So, without specifying actual reasons behind inability to make engine by GTRE, it is incorrect to simply insist on M88 core
Also, with the experience gained from past 20 years, manufacturing of Al31 in HAL Koraput why would one even think of M88 core? Why have such mentality that India is filled with incompetent people who won't be able to make an engine?
China have already made WS 10 engine and WS15 engine by 2010-15. So, without specifying actual reasons behind inability to make engine by GTRE, it is incorrect to simply insist on M88 core
Safronised Kaveri will be IPR of GTRE and any help from france is part of Offset obligations. How they do it is upto them. But the final product will be 100% Indian and will have 100% components made in India in it. It appears to me that France has moved to some very high tech in engine tech and they consider parting away with M88 tech an option.
The size of higher rated engine will be larger. Its diameter will be too big to fit in Tejas or its length will be too much that will reduce fuel storage by extending length. For a small light fighter, this won't be a acceptable
Sir , I had actually buzzed you with this query reproduced below . I wonder if it escaped your attention. Would you be kind enough to shed some light on this ?
Thanks in advance .
Good to know the unstable factor of Kaveri has become stable.
@Aashish no matter how delayed we read your bullet points, we still love it .
The thinking process went behind a decision is such a juicy read , no matter delayed its worth the wait.
@Aashish no matter how delayed we read your bullet points, we still love it .
The thinking process went behind a decision is such a juicy read , no matter delayed its worth the wait.
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The dry thrust of Kabini core had been stabilised over 5 years ago at about 55kN. Even in the wet thrust, India had only last mile problems and not critical problems like melting/bending of blades etc. In 2015-16, France had stated that 75% of engine is complete. So, by all means, the Kabini core was almost perfected till then. France doens't have a flat rated engine with it and the M88 is 50/75kN engine. As many have pointed out, if M88 has to be made into 90-100kN engine, core will have to be redesigned and France is unlikely to build a new engine for the sake of India
So, M88 core is unlikely to suit the flat rated design of Kaveri nor will it suit the thrust requirements. The one coming out will have Kabini core itself and not M88 core. There is no need to hope that the core will be made in the future. It is already made and is being perfected. The Kaveri will come out with Kabini core itself.
The airflow requirement of Kaveri is 78Kgs/sec which is more than that of F414INS6 engine. The F414INS6 engine is rated for 65/108KN thrust but reduced to 62/98KN thrust to extend engine life. Kaveri engine was designed with variable cycle and allow for higher bypass ratio than M88 engine of 0.5 compared to 0.3 for M88. Plus kaveri design is supposed to be flat rated. if you remove flat rating part, the thrust shud be 62 KN dry 54x100/87=62KN, and due to larger bypass ratio, it shud be easily be able to produce about 65-70% additional wet thrust. Minor tweaking of bypass ratios and higher TET shud easily create a 72KN dry and 110Kn wet thrust engine. Please remember that the wet thrust of an engine is directly proportional to the unburnt bypass air which is available for re-ignition after going past the hot sections of the engine. In addition, the airflow can be increased not only by increasing the frontal area but also by increasing the RPM of the compressor while keeping same frontal area and also by increasing the compressor stages while retaining same cross section. A good engine must have least number of stages and wide chord fan to allow for lower weight and larger airflow. EJ-200 is one such example.
I stated that core of M88 even if used for Kaveri will have to be produced from raw material stage in India making it 100% Indian engine. But I am more interested in the latest CMC materials which have pushed the TET to nearly 2200*C for new engines. I wud want that tech for kaver and if that happens, we can probably easily look for engines with nearly 150Kn thrust class and based on kaveri design.
The idea is to rope them in using offsets anyway. Like that Euro 1B commitment to invest in the Kaveri.
The DRDO Chief says AMCA requires more than 110KN. The empty weight is estimated to be about 12T, with 6.5T of fuel and 2.25T of internal weapons load. The interim 98KN engine for TDs will not be enough.
What you say makes sense, but that is the official stand right now. Even the Americans put a 110KN engine on their F-15s for the a 12.5T empty and 6.5T fuel load.
The Kaveri will be cheaper than the F404. It requires two years of flight testing before it becomes production ready. So it should become available by 2021, in time for Mk1A deliveries. Plus we have to start somewhere.
Ghatak will be using the dry thrust variant of Kaveri, so Kaveri will be entering production in a slightly different form anyway.
The F404 is fine, but Kaveri will be better.
The K9/K9+ will have fully Indian IPR with French assistance. But K10 will see French/foreign IPR for the hot section added to the engine. It won't be fully 100% Indian.
But we are yet to see movement on the high thrust engine. And the foreign partner may not necessarily be French.
The dates for Ghatak are secret. The total start to operational date is 8 years. Even the French are involved in the software aspects of the program.
But that doesn't change the fact that they are preparing to mass produce the Kaveri.
F15 has 75% metal usage in airframe (aluminum, titanium and steel). So, it has higher empty weight. The 5th generation planes will have large carbon composite usage and weight will be lower - 10tons.
The internal fuel of 6.5 ton and 2.5ton of payload will be too big and may result in the plane being a flying tank. The big F35 itself has 8.3 ton fuel and 2. 5 ton payload and as a result is poor in aerodynamics despite bigger dimensions. So, likely fuel and payload can be 4.5 ton and 2 ton internally. In addition, 7 ton of external stores is possible for total MToW of 24tons.
I don't see a reason why should AMCA have twin engine of greater than 72/110kN thrust. F15 has MToW of 31tons and uses twin engine of 110kN and that bodes has similar thrust to weight as Tejas. Whereas a 24-25ton plane having twin engine of thrust higher than 110kN will be fuel guzzler. I would say that twin 100kN engine would also be sufficient going by the thrust to weight ratio for AMCA and may even prove to be better in range
For hot and high Indian climatic conditions, you need at least 10% additional thrust for every aircraft compared to what is available on Western aircraft.
I have a different view on it. Most Russian engines have still not reached the same TET as that of western engines, but they too have very high thrust engines. Kaveri in its present form does not have BLISK. Once you put BLISK, the frontal diameter on the hub reduces resulting in higher air flow for same frontal area. add to this higher pressure ratios between various stages of fan and compressor and you will be able to meet the requirements of higher mass flow for enhanced thrust without having to change the fan diameter or engine dimensions. Regarding the hot core, yes the core is limited by the TET it can withstand and the max thrust that can be produced from it based on various factors like internal cooling etc. If I remeber correctly, @Picdelamirand-oil and @halloweene had mentioned that M88 core is fit for 11 ton thrust. Slight modification using the CMC materials giving higher TET will easily allow Kaveri to hit 130KN thrust easily.
The airframe weight is typical 50% of the empty weight for a single engine fighter and about 40% for a twin engine fighter. The weight saving that can be done is from this empty weight only. No fighter can ever be build with 100% composite materials. So the maximum weight reduction possible is only of the order of 10% of the airframe weight or about 5% of the empty weight. LCA is one such example, even with very high composite content, it has not been able to meet its design empty weight. Mig-21Bison with its nose cone extended has a length of 13.46m from nose cone tip to engine tip only. The over hang due to rudder and tail plane is not included in these calculations. It also has a 4.615 m long engine which weighs 1212 kgs. The empty weight of all metal Mig-21Bison is 5950 kgs. Now we have LCA which is 13.2m long, has an 3.91m long engine which weighs 1072kgs and has an empty weight of 6500kgs that too after having 45% weight of airframe by composites. So make your guess what is better.
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