OMG, this thread expanded so fast.
DoD/security plans & deals're supposed to appear tricky, so that enemies can't adapt prematurely.
> IM

In short,
- Looking at USA's arm twisting, no F-35 or any future jet &/or engine. After 80% F414 ToT also be mentally prepared for 20% arm twisting.
- Few squads of Su-57 50-50 chance. Although Su-57 has many cool stuff but we should not see Su-57 as true 5gen but 4.5-5gen gap filler better than any 4.5gen jet. Hence getting it or not, i'm neutral.
- We can take 1 of the new Russian engines & inflate AMCA like LCA to MWF, similar to Kaan. Ultimately our own domestic/JV engines matter.
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Expanding the short lines -
- USA makes good quality products but in return expects world submission/domination.
- Jets remain for 40-60 years but Regimes can change every few years, so to avoid further arm-twisting & delays, we should limit our purchases from them to auxilliary systems & products like helicopters, cargo planes, equipments, etc for which alternatives are there globally & locally. That would be enough for international trade & diplomacy. So we shouldn't even dream of F-35 or even export variant of NGAD, F/A-XX, their CCAs.
> Action speak more than words, for US & us too. World is already pointing to most populous nation's bureaucratic management & delays.
- Indians succeed abroad but struggle locally & with AI/ML there'll be global impact & forcing priority on local employment, so many NRIs will have to return to India.
- Expanded DoD employement & PPP need to absorb the talent. It's not good to keep going to shopping abroad even to friendliest nations like Russia, France, israel, etc.
- AMCA plan A with F414 along with inflated plan-B. Citizens are already in shock after 15 years thinking earlier that the prototype is half way under construction until this PPP news disclosed the real state of progress.
- Bcoz new airframe & engine design take 10-15 years at least hence just like GTRE's effort & JV engine, we also need our own heavy class 5+gen airframe along with appropriate engine to be officially started immediately, later upgraded to 6gen when DRDO making RAM, RAS, DEW, TVC, etc. We don't need a complete capitalistic GCAP, FCAS system, just some of their components & technology which EU'll agree or not is tentative. If ADA can't design new airframe then PPP should do it.
> We've to be carefull with products of EU & Russia too bcoz friendly politicians can't remain in power indeinitely & every nation's defence products' export variant is supposed to be inferior to its domestic variant, to maintain a leading strategic & industrial advantage & business continuity.
- Although Su-57 has many +ve points like flatter fuselage, DIRCM, levcons, TVC, IRST, multi-band DAS-MAWS, side & rear looking radars, multi-band RF antennas, new HMDS, glass cockpit, etc, but its RCS is not satisfactory from 5gen PoV, contributed by many aspects like round engine bays, round IRST, IFRP, canopy arc, etc.
- Regular citizens/enthusiasts are not historians, journalists, so as per internet search & chatter on other foreign forums, Russians don't seem to claim Su-57 front RCS lower than 0.1m2, that's just 1 decimal place lower than the Western MLUed 4.5gen jets with 1m2 RCS in clean config.
- So for public understanding -
F-22 - 0.0001m2
Domestic F-35 - 0.001m2 or b/w 0.001 & 0.0001 m2.
Exported F-35 - <=0.001m2
Domestic Su-57 - <=0.1m2
Exported Su-57 - ??
MLUed 4.5gen clean config - 1-5m2
Initial 4gen - 5-25m2
- So <=0.1m2 RCS Su-57 can kill 1+m2 RCS 4.5gen jets, but even if world's best avionics is put inside a fuselage which's still visible 1st could be vulnerable to enemy 5gen jet & SAM, then the incoming BVR-AAM/SAM has to be decisively jammed to survive. Some missiles have HoJ (Home on Jam) capability so that has to be countered by ECCM.
- In next few years when AMCA full scale RAM+RAS+EW model will be tested in anechoic chamber & RCS range, then DoD'll know its RCS which'll be desired to be at most 0.001m2 like F-35.
- If we intend to use networked fusion then enemy can also use it.
- LR-AAMs/SAMs R&D or import also seen on both sides.
> Some points on engine performance -
- It does vary as per weather, geography, giving 5-10% more dry thrust in cold/dense sea level areas & 5-20% less dry thrust in hot/thin air sea level areas. There'll be some trade-offs.
- Russia is cold region, Europe is also very cool. USA has diversified geography & climate. Their jets & engines have been used globally,
- Engines thrust're quoted as per testing in chamber with conditions of sea level STP, also tested in heated & cold air to simulate real world, keeping a cap or flat-rating limit to avoid damage.
- In hot areas bcoz the air is pushed up, as altitude rises the performance differences decrease. Hence the hurdle is the initial takeoff at higher runway &/or hot climate.
- Important IAF bases like Gwalior, Ambala, Bikaner, etc used in Op-Sindoor for example, in summer can have 10-20% loss of air density, dry thrust & lift compared to STP.
- In lower air density, by rule of conservation of mass, the velocity(volume) needs to increase to compensate for lower air density, means higher T/o & flight speeds, means longer runways.
- And lift also needs sufficient air density.
- So when enough runway, Afterburner can be lit when jet is stationary bcoz it's direct fuel injection & fuel's calorific value is very high giving big KE to air molecules compensating for dry thrust loss, provided the engine thermal materials are good & a jet can still t/o with full MTOW.
- But if runway is limited then any jet can t/o with 80% of MTOW, more payload, less fuel then do mid-air-refuelling.
- But if airfield is higher like in Tibet then it's bigger problem bcoz air density drops by 35-40%, dry thrust drop by 40%, T/o speed increases by 30%, the runway length to like 5 Kms.
- IDK exactly how much AB's wet thrust can compensate this loss of dry thrust but internet search shows J-20 or any jet can still t/o with around 70-80% of MTOW with AB, 46% empty, remaining 24-34% weapons+internal fuel.
- So if 18.4 tons empty Su-30MKI carrying Brahmos & many AAMs with AL-31FP engine is manageable with longer T/o distance, then 18.5 tons empty Su-57 with any higher thrust engine'll also be manageable.
- If Russia allows airframe modification then we can use it for 6gen TD.