fanne wrote:sorry JayS, I still stand by the comments I made about the design parameters around AMCA and it's engine. Time is now to choose the right path (and I am not kidding myself that writing in BR forum would have much of an impact, but do see that many twitter handles have tweeted), I am all for AMCA, but around a engine that either exist now, or have a relatively sure future plan to exist, rather than build it around an engine that does not exist now, nor any known design house is planning to make. In either case, we can have our own effort.
LCA was prudent in that sense, it was around Kaveri, which was slightly souped up F404.(planned Kaveri was roughly 10% more in dry thrust and 3% more in afterburner than original F404). Thankfully for us GE ended up developing F404-ge-in20, that had better performance than planned Kaveri,~4% more). This stroke of luck saved LCA. If there was no F404-GE-IN20 and since Kaveri had failed, the vanilla F404 (with 48.9 KN dry thrust, 78.7 KN afterburner), IAF would have abandoned LCA as an underperforming plane. Remember LCA came about a ton overweight than planned.
We should learn from that experience and not go through the same for AMCA, built it around a known engine, or a guaranteed derivative from a foreign player (since we do not have a sure shot capability to built it ourselves). If it is 110KN, so be it, but then the time to get into an agreement with the foreign power is now, before we embark on AMCA. Least risky is to design around an existing engine (or a guaranteed planned future variant).
You are simply shooting off the hip here and expecting others to provide you data, facts to correct whatever you are suggesting. Instead, you can spend the same time on internet and then post here a well thought out post. Then everyone learns. Had you done a bit of homework, you would yourself realized issues with your thinking. They are pretty obvious ones.
- AMCA is a 5th Gen Fighter with internally carried weapons and good emphasize on Stealth. Need of large internal volume, compromise on aero configuration for stealth et al necessarily force the designer to adopt aerodynamically sub-optimal solutions or in other words draggier airframe than what could have been possible otherwise.
- Stealthy features like S-duct, rectangular exhaust reduce effective installed thrust of given engine (rectangular exhaust can reduce effective thrust by 15-22% IIRC).
- Super cruise enforces a requirement of low bypass engine. Plus to reduce design creep you need as small size engine as possible with high TWR. Plus higher thrust than usually would have needed to compensate for sub-optimal intake and exhaust designs for stealth.
- For a 25T class aircraft no engine exists which fits the bill.
F119 was specifically designed for F-22 and it is not available to us. The only available options are EJ200 and F414. The former has little growth potential or indeed any visibility on growth. F414 OTOH has demonstrated technology capability for 115kN thrust, albeit at reduced life. And it has the highest probability of getting funded for industrialization of that technology, as brar_w has pointed out many times. In fact the probability has only gone up with renewed push from USN on F/A-18 blk III. But we cannot dictate time line and that is the risk we have to take. USN will take its own sweet time to fund it and it is not looking in any particular hurry right now.
- ADA has no real choice here. In fact IMO their hands are tied due to the thrust capability of even the future F414EE version's dry thrust being limited, else they could have enlarged AMCA with two side bays for CCM by going couple of Ton higher in MTOW. It would have been well worth it and I'm pretty sure IAF would have loved to have that capability.
- In given constraints, ADA proposed to go with existing F414-INS6 and have only a partial super cruise capability for now. And side by side develop Desi 110kN engine. F414 EE, if and when available could be a back up. But its important to have a clean sheet 110kN engine with smaller BPR. It will also have a good 10-15% organic growth potential for future of AMCA. This was in 2012-13. IAF seems to have accepted this proposal. There have been talks of Kaveri -110kN version development since at least 2014 if not from earlier. That time we had about 20yrs to develop such engine. But GOI wasted 5-6 yrs in begging to France and wild goose chase with DITT, instead of funding our own people (need not be GTRE, we could have formed an institute like ADA for engines, including Pvt industry from outset). And now we have only wasted as many years and have not moved an inch from where we were.
If anyone wants to suggest alternate engines, look at the ratio of their dry thrust to wet thrust and TWR. Compare it to F119 as a benchmark and then you will see why options like AL-31 or F100 make no sense whatsoever. The engine that the Japanese are developing for their next-gen fighter matches well with F119 on these parameters, IIRC. We need similar engine.
Without critical thinking we just end up producing noise and a heap of posts with little value addition.
PS: Supercurise is always expected for max internal weapons load. Any external load and expecting the fighter to super cruise is unreasonable.