Advanced Medium Combat Aircraft: News & Discussion - 30 August 2019

[nachiket]

The AMCA needs a 100KN engine first. Lets think of TVC after that.

Or not think of it at all. The applications of TVC on a modern battlefield (not air-show displays like that F-22 earlier) are questionable. Most of the MKI's great maneuverability (in a battlefield context) is provided by its design and available thrust rather than the TVC. Both the Su-27 and the Mig-29 could perform Pugachev's cobra and the tail-slide for instance without using TVC. The issues with using the Cobra or other TVC enabled post-stall maneuvers in actual combat were pointed out very well by AM Harish Masand in his interview (fighter pilot podcast). He specifically mentions that he would rather have more thrust and less weight (TVC mechanism increases weight) in a dogfight rather than whatever advantage the TVC itself would give because post-stall maneuvers make you lose speed very quickly and while that can perhaps get you a first-shot advantage against your immediate adversary you will be a sitting duck for his wingman or another enemy aircraft in a multi-aircraft engagement because of your very low energy state following the maneuver. Now this is a guy who is famous for his great flying displays in the Mig-29 (not to mention his Sabre kill in 1971) so he knows what he's talking about.

I'm not saying that TVC is useless, but you have to be willing to make compromises, primary one being additional weight and then carefully look at whether the advantage you will receive because of that is useful enough. The Americans decided it wasn't when they designed the F-35 after the TVC enabled F-22.

[MeshaVishwas]

Mighty impressive kit from Khan. Will be the benchmark for decades to come and if the AMCA stays true to the philosophy of the design...will be a really scary foe.

Interesting comment on the AWACS at 74 minute mark.

[brar_w]

I'm not saying that TVC is useless, but you have to be willing to make compromises, primary one being additional weight and then carefully look at whether the advantage you will receive because of that is useful enough. The Americans decided it wasn't when they designed the F-35 after the TVC enabled F-22.

The F-35 did not have the performance requirements of the ATF (to put it gently), and the YF-22 met objectives even without TVC (Lockheed thought that USAF may clip it so over designed). But beyond that simple TV approach,and the post-stall benefits, future TV approaches would probably play a very significant role given future LO signature requirements and other benefits. Lockheed Martin pitched this to USAF/NASA on the X-44 MANTA and Boeing even validated it on one of their technology demonstrators that flew with the system.

[nachiket]

The F-35 did not have the performance requirements of the ATF (to put it gently), and the YF-22 met objectives even without TVC (Lockheed thought that USAF may clip it so over designed).

Would that be because some of those requirements were not found to be particularly essential or important? Considering that the USAF will operate 1700+ F-35's and only 180 F-22's, I am sure the F-35's will be called upon to perform pretty much every mission that the F-22 would (and more) if there is a hot war.

I'll keep it simple, what mission can the F-22 perform because of its TVC that the F-35 cannot? And for most of the F-35 customers outside the US, that will be their "tip-of-the-spear" so to speak, the most advanced aircraft in their inventory for the next few decades at least, considering that none of them have access to the F-22. SO the F-35 will be their primary air-superiority as well as deep strike fighter. AMCA will be expected to perform a similar role for the IAF and needs to be procured in numbers. It is not supposed to be an F-22 like silver bullet.

[Nilanjan]

The AMCA needs a 100KN engine first. Lets think of TVC after that.

100/110 kn
Wet thrust is not so much important,importent is 70-80 kn dry thrust.supercruising at 1.6-1.7 will be the real streamth of amca

[nachiket]

80kN dry thrust is too much to ask from an engine the size of F414. And we cannot increase engine size without increasing the size of the aircraft. The current F414 produces 58kN thrust dry. A good target to set would be to ask GE what would be the max dry thrust of their EPE offering and set that as a target for our indigenous program as well. It will take herculean efforts (and funding) to reach that level itself for an indigenous program.

Even 65kN of thrust per engine at military power should give the AMCA a better t:w ratio (dry) than the F-35, assuming that the projected empty weight and MTOW specs we have seen at Aero-India etc. are not exceeded by a large amount. Whether that will be enough to make it supercruise, I don't know.

[Prasad]

The AMCA is designed for an engine larger than the GE-414.

[brar_w]

80kN dry thrust is too much to ask from an engine the size of F414. And we cannot increase engine size without increasing the size of the aircraft. The current F414 produces 58kN thrust dry. A good target to set would be to ask GE what would be the max dry thrust of their EPE offering and set that as a target for our indigenous program as well. It will take herculean efforts (and funding) to reach that level itself for an indigenous program.

From where is GE going to pull that one off? Who will fund it? What technology, at what readiness levels will they use and what upside benefit do they have of doing this? From what we know, neither South Korea, nor India has been willing to fund extensive development so the dry-thrust of the F-414 engine that will power this will remain the 56-60kN class of the current engine though top end thrust (afterburner) could be increased. You are talking about what essentially amounts to a new engine. No matter how much money one throws at it, one is not going to transform the F-414 into a 5th gen F119/135 level of engine. At some point it is just better to just go into a completely clean sheet design.

If you want Raptor like supercruise performance (as described in a post above) you need an engine that fields F-119 (or better) level of technology along with other design decisions ranging from materials, to signature, inlets, payload etc etc etc.

[nachiket]

From where is GE going to pull that one off? Who will fund it? What technology, at what readiness levels will they use and what upside benefit do they have of doing this? From what we know, neither South Korea, nor India has been willing to fund extensive development so the dry-thrust of the F-414 engine that will power this will remain the 56-60kN class of the current engine though top end thrust (afterburner) could be increased. You are talking about what essentially amounts to a new engine. No matter how much money one throws at it, one is not going to transform the F-414 into a 5th gen F119/135 level of engine. At some point it is just better to just go into a completely clean sheet design.

If you want Raptor like supercruise performance (as described in a post above) you need an engine that fields F-119 (or better) level of technology along with other design decisions ranging from materials, to signature, inlets, payload etc etc etc.

I don't disagree with any of that, which is why I started off saying that we should not expect unrealistic dry thrust values. I haven't seen any info from GE about what the dry thrust of the EPE is supposed to be. They only mention that the wet thrust will be in the 116kN range while the airflow will increase to 85kg/sec from 77kg/sec (I suppose that should provide a dry thrust increase?).

Problem is it is not currently within India's capability to design and develop an engine with F119 levels of technology. That gap is too large. I would be surprised if any engine manufacturer in the world besides GE and PW have that technology available. So that puts us in a fix.

Now Prasad says the AMCA is designed to fit larger engines, which is news to me. Larger by how much? And what effect will that have on the intake design if later versions are supposed to work with larger engines which will require significantly more airflow? And where will these engines come from?

My point is that expectations of F-22 level performance (supercruise) should be heavily tempered right now taking into account the reality of engine performance available (from anywhere, not just indigenous programs). It is important to set realistic goals.

[brar_w]

To the best of my knowledge there will be no significant increase in the dry thrust of the EPE which itself is not funded right now. I agree about the expectations. I was merely pointing to the post which says that the AMCA will SC at Mach 1.6 to Mach 1.7 which is going to be very tough to get without a significant increase in propulsion compared to the F-414. This will have second and third order impacts elsewhere (range, loiter, payload, materials, cost etc. etc.). There are other more pressing technologies that need to be developed, and volume production mastered that, collectively, will still make the AMCA very potent.

[Nilanjan]

I have been watching drdo performance from last 6-7 years and there was a time when expecting any futuristic weapon from drdo looked like utter stupidity.but drdo stunned me with the swiftness in the projects like qrsam,mpatgm and many more.even the amca aerodynamical and structural design,which just 3-4 years ago seems to be impossible without russian help through fgfa jv but now we are super confident abaout that aspect.similarly about engine devolopment also we shouldn't doubt the momentum drdo gained in last 4-5 year.we should be going for it complete indigenously with clean sheat design using past experience instead of wasting time by begging to u s. Or france.drdo chief reddy in some recent interview clearly indicated that groundwork for a new engine is already done now govt. And air force should go ahead with new design and pump some money instead of wasting it on mmraca or another 36 rafale

[Nilanjan]

Just money of 3 rafale can give us a new higher thrust engine and a jet far superior than f-22

[sankum]

Delighted to hear that. For $750m a new engine.

[nachiket]

Just money of 3 rafale can give us a new higher thrust engine and a jet far superior than f-22

It is not just a question of throwing money at the problem. The Chinese have sunk many times that amount into various engine programs by now and they are still catching up with the Russians, forget the Americans.

[Nilanjan]

Just money of 3 rafale can give us a new higher thrust engine and a jet far superior than f-22

It is not just a question of throwing money at the problem. The Chinese have sunk many times that amount into various engine programs by now and they are still catching up with the Russians, forget the Americans.

I agree with you,but if govt. Pump some money drdo can try it's best.if they not get desired result still we can satisfy that atleast we tried our best.currently engine devolopment infrastructure in our country is pathetic,drdo's achivement respect to this condition quite good.i am not telling to increase defence budget,but increase r&d budget instead of some gold coated import.

[kit]

Just money of 3 rafale can give us a new higher thrust engine and a jet far superior than f-22

It is not just a question of throwing money at the problem. The Chinese have sunk many times that amount into various engine programs by now and they are still catching up with the Russians, forget the Americans.

better to do and maybe not reach there than never to do at all .. Who knows Indian jugaad will come around to it as well

[nachiket]

Don't get me wrong, we most definitely need to pump in large amounts of money into a new domestic engine program for the AMCA. But our finances being what they are that amount is not going to be anywhere near what would be required to realize an engine with the kind of performance that is being talked about here. Especially while also spending money on the AMCA aircraft project itself.

The way I see it, the AMCA has a much bigger engine issue than the LCA ever did despite the Kaveri not being a success. The GE-F404 was initially supposed to be a stopgap, until the Kaveri was ready, not because it did not have the requisite performance but because we wanted an indigenous engine. So when the Kaveri wasn't successful, the LCA itself wasn't affected because the F404 could still be used.

But for the AMCA not only is the initial stop-gap engine (F414) not indigenous, it also does not have the required performance, nor any path to a new version which might. So if the indigenous program fails to achieve these cutting edge specs (even better than the F414 EPE from what I can see), the entire project might be in trouble. That is what scares me.

[nachiket]

Forget about GTRE and our current capabilities, even if it is a JV, does Safran or RR have the technology available to develop an engine the same size as (or even slightly larger than) an F414 but with 70kN+ max dry thrust? I doubt it. Collaboration with a US manufacturer is probably out of the question.

[JayS]

To the best of my knowledge there will be no significant increase in the dry thrust of the EPE which itself is not funded right now.

We had some discussion on this some time back. I remember to have seen one data point on EPE that GE managed to increase the TET with advancement in the cooling tech by 64K which either can be used to increase the thrust or to increase life of the parts from 2000h to 6000h (must be HPT). There was no data on how much thrust increase, but if the TET is increasing then dry thrust has to increase too. Plus there was some PIP for compressors as well IIRC. As such I feel if all 20% thrust increase has to come from AB, it will be a serious hike in fuel consumption.

[JayS]

Please move the engine related discussion to Kaveri/Engines thread.

[Rakesh]

I moved most - not all - of the posts into the Kaveri thread. Thanks.

[TushS]

I just have a thought that are we indulge too much in Tejas that we have forgotten AMCA completely? IMO, we need to rush for AMCA as much as MK-2. We wouldn't like AMCA to induct beyond 2040. More news should come out for AMCA and mk-2 should be serves as TD for all it's techs.

[chola]

Don't get me wrong, we most definitely need to pump in large amounts of money into a new domestic engine program for the AMCA. But our finances being what they are that amount is not going to be anywhere near what would be required to realize an engine with the kind of performance that is being talked about here. Especially while also spending money on the AMCA aircraft project itself.

The way I see it, the AMCA has a much bigger engine issue than the LCA ever did despite the Kaveri not being a success. The GE-F404 was initially supposed to be a stopgap, until the Kaveri was ready, not because it did not have the requisite performance but because we wanted an indigenous engine. So when the Kaveri wasn't successful, the LCA itself wasn't affected because the F404 could still be used.

But for the AMCA not only is the initial stop-gap engine (F414) not indigenous, it also does not have the required performance, nor any path to a new version which might. So if the indigenous program fails to achieve these cutting edge specs (even better than the F414 EPE from what I can see), the entire project might be in trouble. That is what scares me.

Yes, that worried me as well. They are asking for a 110kN medium engine (kaveri/rd33/f404) when the heavyweight al-31 is at 124kN. More ambitious than even the Kaveri which we attempted with no experience at specs matching the best US and Russian medium engines of its time. This time we are asking for specs better than any US or Russian medium engine. I don't even think they have anything even in development beyond the F414EPE because their focus is on heavy engines. Maybe a uprated RD-33 for the mythical MiG-41.

[Aditya_V]

Exactly can we atleast design the AMCA so that slightly heavier and wider dimension engine than the GE 414 fits. Al31FP will be too big heavy, but some engine which is realistically possible. And please but the wind tunnels testing aircraft etc. This going to Russia to test the engine is recepy for disaster. If we don't want to invest, we can't expect GTRE /ADA to deliver.

[brar_w]

Yes, that worried me as well. They are asking for a 110kN medium engine (kaveri/rd33/f404) when the heavyweight al-31 is at 124kN. More ambitious than even the Kaveri which we attempted with no experience at specs matching the best US and Russian medium engines of its time. This time we are asking for specs better than any US or Russian medium engine. I don't even think they have anything even in development beyond the F414EPE because their focus is on heavy engines. Maybe a uprated RD-33 for the mythical MiG-41.

The US Navy has a 6th generation fighter engine program that it's been running for a while now (for some time it was passive to the USAF adaptive engine program but with hooks thrown in for naval applications, but now it is getting ready to sprout towards a naval direction as a separate program). Though thrust requirements for it are unlikely to be in the F-414 class, they are probably also not going to be in the F-135 class (USN can't afford something as large as the USAF is likely to want so will water down overall aircraft dimensions). Perhaps somewhere between the F-414 and F-119 is where they'll end up. But the problem will still be that the USN aircraft will probably still be on the larger side of naval fighters (perhaps similar to F-14) so those engines may be too big for the AMCA..Besides an indegenous application, until the Tempest or FCAS is fielded I really don't see an advanced completely new engine in the exact category..This (F414 class of engines and engine tech) is just what the AMCA and the Korean F-X have to live with for the foreseeable future until home grown or more foreign options are available.

[chola]

Exactly can we atleast design the AMCA so that slightly heavier and wider dimension engine than the GE 414 fits. Al31FP will be too big heavy, but some engine which is realistically possible. And please but the wind tunnels testing aircraft etc. This going to Russia to test the engine is recepy for disaster. If we don't want to invest, we can't expect GTRE /ADA to deliver.

Not really, the world has through much trial and error come down to two main classes for frontline fighters:

Medium -- F404/F414, RD-33/93, M88, WS-13, Kaveri; all around 50kN dry, 75kN wet; new devs in this class are WS-19 and the purposed AMCA engine;

Heavy -- F100/110, AL-31/41, WS-10; all around 75kN dry, 125kN wet; new devs are WS-15, Izdeliye 30 (for SU-57);

The F119 and F135 are outliers. They are superheavies and so powerful that they can't be used for anything but the F-22 and F-35 respectively: 116/120kN dry, 156/180kN wet.

There really isn't anything in between the medium (Kaveri) and heavy (AL-31P for MKI) that we have experience with. This new engine is a tall order because the stated goal is near heavy power but in medium dimensions.

[brar_w]

FCAS and/or Tempest will probably end up in the 12-14 K kg class (empty) and 30-35 K kg (max) just given affordability grounds alone (and export prospects which are going to be important for both programs). That should result in an engine that would be of interest to the AMCA. At least one of these programs will probably make it across the finish line by the late 2030s. But propulsion solutions for both are 10-15 years out realistically (as mature solutions to be offered as a stand alone option).

[Prasad]

AMCA's engine will be smaller than F110 and bigger than F414. First 2 squadrons will fly with F414s.

[chola]

Brar ji, I would love to see the engines for FCAS (have Germany/France even made this official?) and the Tempest. But those seem to be Gen 6 type projects! I need to look into the new USN engine. Sounds interesting! But with the F-35/F135 how much of a priority could it be?

I think the real question is why we didn't look at a fighter that's a followon to the MKI that can use the AL-31 engine class engines. We have a heavy fighter that form the core of the IAF and we have some experience building the AL-31. A heavy fighter might be more in line with our skills and India's size as a continental nation? There is a readin why the Russians and chinis settled on aircraft the size of the Flanker as their core. So do the IAF right now. Why go with a smaller aircraft with more challenging specs?

[chola]

AMCA's engine will be smaller than F110 and bigger than F414. First 2 squadrons will fly with F414s.

If it'll fly with the F414 then the dimensions will be roughly the same. The F-15 as big as it is cannot accomodate the F119 of the F-22 though people in forums had salivated at the thought! Or imagine the F-16 with one. lol

It'll be an engine of the same class after the first two squadrons.

[Prasad]

AMCA's engine will be smaller than F110 and bigger than F414. First 2 squadrons will fly with F414s.

If it'll fly with the F414 then the dimensions will be roughly the same. The F-15 as big as it is cannot accomodate the F119 of the F-22 though people in forums had salivated at the thought! Or imagine the F-16 with one. lol

It'll be an engine of the same class after the first two squadrons.

No man. Read http://delhidefencereview.com/2019/11/1 ... elopments/

[brar_w]

Brar ji, I would love to see the engines for FCAS (have Germany/France even made this official?) and the Tempest. But those seem to be Gen 6 type projects!?

There is no "5th generation" engine program out there for this thrust class at the moment besides home grown options. The Europeans are going to pursue 5+ or even full up adaptive engines for their aircraft. Given the timelines that should pretty much be a requirement and that is reflected in some of the initial plans revealed though funding still remains low.

[chola]

If it'll fly with the F414 then the dimensions will be roughly the same. The F-15 as big as it is cannot accomodate the F119 of the F-22 though people in forums had salivated at the thought! Or imagine the F-16 with one. lol

It'll be an engine of the same class after the first two squadrons.

No man. Read http://delhidefencereview.com/2019/11/1 ... elopments/

Saar! Unless the AMCA MKII is radically redesigned, it cannot take anything other than a medium class engine. In fact, the article clearly states that the new engine us supposed to be able to be "dropped-in" into the original AMCA TDs.

Again, this is what makes it hard. They are asking for a 110kN engine in medium engine dimensions. As the Brar stated, there is no even "5th gen" engine programs that can satisfy that now. You are looking at things like the FCAS and Tempest to see equivalents.

If we can do this, we'll be at the forefront of engine tech! I hope we do it! But it is a huge challenge, even bigger than Kaveri and Kaveri was a very ambitious moonshot.

The AMCA MkII is expected to be produced in greater numbers than the MkI and will be equipped with new engines in the 110 Kilonewton (KN) class that will allow the entire performance envelope of the AMCA baseline design to be achieved.
...
At the moment, however, there is no suitable commercially available engine that meets the performance requirements of the AMCA MkII configuration.
...
Unfortunately, even if the issue were to be decided today, this effort would yield a suitable engine only by the early 2030s. Nevertheless, this engine will be designed to be a ‘drop-in’ replacement (in terms of compatibility with connectors etc.) for whatever is used initially on the AMCA-TDs. It is not entirely clear at the moment, whether more TDs will be built in the future to serve the developmental needs of the AMCA MkII configuration.

[Prasad]

You didn't get it. The AMCA will be designed for an engine larger than the F414. Initially they'll run with the F414.
That there is no readily available engine in this class and that they're hinging the entire program on ab-initio development of this new engine is a major risk for the program. But this is what we were told.

[abhik]

^^^
Doubt it, AMCA will be designed for a higher thrust/weight ratio engine compared to F414 rather than larger (size will be more or less same).

Added: In 2030's timeframe you should start seeing 6th gen fighter engines (or 5.5 or whatever they decide to call it) making it into production, So the calculation must be we can get a screwdriver-giri deal on 5th gen tech (without hot section etc. of course).

[brar_w]

Adaptive engines come with their complexities in design and integration. Even the F-22/F-35 cannot accept a full blown adaptive engine (w/o cost prohibitive reddesign) so they are looking at transferring some of the advances made during adaptive engine development to the F-135 program (F-35). Even if it could accomodate a third stream engine, you are then still left to basically integrate that into how the whole power generation, management and heat dissipation system is set up. So fitting a 6th gen adaptive engine into an older fighter is not going to be like dropping in a new engine. It would be a quite a lot more complex than that. This is why you see adaptive engine programs running a decade or so ahead of the rest of the development. Mature propulsion concepts and plans are needed for the airframe designers to work with. So barring a more advanced 4th or 5th gen engine program out there (major T2W increases, dry thrust increase, and signature management capability compared to F414 family) and indigenous engine is probably the best bet. How soon can India develop, produce and operationalize an advanced engine comparable or better than the F-414? That is the question that will need to be answered and will likely determine the timeframes for the full "spec" AMCA down the road. I see both the IAF and the ROKAF in the same boat vis-a-vis this dilemma.

[Prasad]

^^^
Doubt it, AMCA will be designed for a higher thrust/weight ratio engine compared to F414 rather than larger (size will be more or less same).

Added: In 2030's timeframe you should start seeing 6th gen fighter engines (or 5.5 or whatever they decide to call it) making it into production, So the calculation must be we can get a screwdriver-giri deal on 5th gen tech (without hot section etc. of course).

Larger engine. Higher thrust.

[Rakesh]

India’s 5th Gen AMCA Jet To Be Public-Private Program
https://www.livefistdefence.com/2020/06 ... chief.html
29 June 2020

Bid To Choose Pvt Partner In India’s 5th Gen Fighter JV Begins
https://www.livefistdefence.com/2020/06 ... egins.html
29 June 2020

[Rakesh]

https://twitter.com/YusufDFI/status/127 ... 34625?s=20 ----> Larsen & Toubro, Lakshmi Machine Works (LMW) Advanced Technology Centre, Tata Advanced Systems Ltd (TASL) and at least three other private sector defence firms in the run to be an equal partner with HAL for India’s 5G fighter jet - AMCA.

Corporate website for LMW - Advanced Technology Centre ---> https://www.lmwatc.com/

[brar_w]

^^ Reference the Piccirillo ATF/F-22 book to see what sort of industrial eco-system was needed, and created, as part of the Advanced Tactical Fighter program in the US in the 1980's and 1990's which formed the base for much higher level work down the road (and without which the JSF would have been impossible to execute at scale). Very specifically, around LO industrial capability, propulsion, materials technologies, power, and electronics. This is the perfect opportunity for the AMCA to build, by leaps and bounds, over the decades of work on the LCA and create the sort of ecosystem that will be required to sustain future 5FGA, and other advanced combat aircraft (LO UCAV's, Bombers, ISR aircraft etc).