Su-57 should have better lift than flanker despite latter being very good already. It has much more powerful engines, and less drag when loaded. Should have a top speed greater than flanker. Not even considering modern materials, design, and manufacturing for a structure more suited to speed. We know it should supercruise and LEVCONs make maneuvrability in supersonic range easier and without the need to deflect other control surfaces and/or thrust vectoring. Everything shows Sukhoi's approach to the problem is different to F-22's. Both do emphasis high speed and supersonic agility. J-20 wants to play the stealth game with advanced avionics. Everything else is still a mystery. China is keen to see how the Su-57 performs though since India will likely be getting quite a few.
Russian Su-57 Aircraft Thread (PAK-FA and IAF FGFA)
- Thread starter A Bar Brother
- Start date
Tomorrow. Or I'd rather say the day after tomorrow. Because current "wins" are just taking place right now.
China is yet to design and build the whole classes of aircraft on it's own. Aircraft, which occasionally are in service in Russia (and much more so in the US) for generations. Problem is not just engines. Problem is need to duplicate whole spectrum of aerospace industry products.
Furthermore - no particular dislike. I live in China right now, lol . I just remember what however bright modern China is, by design cycle(15 years) terms it looks different.
2017 China, which introduced J-20, and mid-late 1990s China, starting designing it, are two very different countries.
It's just semantics. While I agree Chinese aerospace industry is nowhere near the US, I don't think what you brought up is relevant to the discussion. Whether or not China is an aviation powerhouse, whether there are fanboys and cheerleaders out there arrogantly shouting about China's successes or not, DSI intakes are used by F-35 and J-20. Also by FC/J-31. These also happen to be the latest fighters disclosed by both nations. By associating China's choice of using DSI with that of the Americans, I am not claiming they are in the same league. In fact, I've mentioned otherwise several times. Beyond what we consider a powerhouse, these are the facts. Don't care about the rest of what you say. You seem to like introducing totally irrelevant topics into a specific discussion. The flavour of your writing is always the same. China is basically not as good. While true, put it into context and you may start seeing why there are members here who are enthusiastic about China's progress. In this case, it's not important how to best describe China's aviation industry. I think the intake discussion should end though.
They are. And they're not used by Su-57 for reasons different from Russia being incapable of introducing this tech.
Since we obviously don't know actual facts, we can only guess.
1)plane probably was specified to be very fast, with or without afterburner.
2)plane equally is also very likely to have very high requirements for endurance, both subsonic, supersonic and on afterburner. Thus as much efficiency as possible is a must.
It forces design choices, including sacrificing at least some stealth (dsi is better in this regard, no question).
Engineer
Major
You are assigning priorities where none exists. In your attempt to dismiss the paper, you completely forgot that variable geometry wing has to reduce aspect-ratio for supersonic flight. The thesis of the paper is to use low-aspect ratio wing to lower supersonic drag, then use other means to achieve high transonic lift-to-drag. High-aspect ratio wing is not needed. The solutions referenced by the paper address all the actual requirements that variable geometry wing addressed.
The design method you cited doesn't explain any advantage or drawback as compare to other inlet types. It hasn't touched upon the operation principles. Furthermore, pressure recovery isn't the only performance metric. On paper, one can keep adding additional surface to improve pressure recovery. In practice, each additional surface increases inlet drag, and the volume and weight require to actuate all those surfaces increases dramatically. The F-15 inlet is the limit of what can be physically implement.
I agree that variable geometry inlet is better suited for Su-57, but not for the same reasons as you.
Unlike the Caret inlet on F-22, the variable geometry does most of the work in Su-57 inlet, and the Russian is very familiar with variable geometry inlets already. LEVCON has similar size and is located at similar location as the canard on Su-30 MKI. Yaw instability is addressed by TVC which the Russian have already been using for a long time. Test flight of JF-17 was already well in progress with fixed inlets before the fourth prototype with DSI appeared. The fourth prototype played the role of test demonstrator.
At this stage it seems that India is likely more interested in the F-35,, they do NOT appear to be pleased in any way shape or form with the turn of events with PAK-FA, in fact the first Indian pilot, has yet to fly the F-35!
SU-57 supposedly having better lift than the Flanker, and as a result a higher top speed is nonsense,, when you make lift you are creating drag,,, that's why the SU-57 has likely had its max top end lowered...
Nobody ever really runs their bird up to "flank speed", unless there is a missile on their tale, and that happens so infrequently.. in any regard, aircraft are being engineered to be optimized at around Mach 1.6 to 1.8 for supercruise,, the F-22 will do it, the SU-57 is a question mark, maybe 1.2 to 1.4,, I haven't seen any real data with hard numbers on the Russian team?? as for the other black bird??? I just don't think she makes enough dry thrust to push through??
Now I will say this, the Russians did make a run or two,,, maybe more, at very high altitudes and very high speeds,,, but I do believe they also "toasted their turbines!", not what you want for breakfast..
So, yes, I would agree the SU-57 does likely make very good lift, its also very agile,,, but those two items basically also tell me that top speed has been dialed back to a usable real world number, like the say Mach 2+, which is still Very Fast!
I stand corrected on lift. But lower drag is still true for Su-57 since it carries weapons internally. Also has more powerful engines so a higher top speed is very likely. Especially considering Sukhoi wants very convincing loaded supercruise ability and does seem to emphasis speed with its design. What India wants will remain a mystery until they get it. They have a habit of dragging defence procurements out for ages. Usually not for secrecy reasons but probably corruption and internal disagreements.
Russia has been playing games with India, they took their money, and then held out on disclosure,, so lets put this ball back in Russia's court. Russia has promised something they can not and will not deliver,,, that's the main reason India hasn't been allowed near the actual data, nor been allowed to fly an aircraft they have partially funded..
Yes, I am aware of India's gymnastics on the Rafale deal, they probably could use a lesson in "getting things done", but nobody in this deal trust the other to do what they say,,,, "guess there really is "No honor among Thieves", and I'm just being facetious here, but really???
any way LockMart is ready to manufacture the F-16 in India, so we'll see how that turns out,,, I can't say I have any faith in that deal either??
I'm not forgetting anything, nor am I dismissing the paper - it's an excellent source (it can't help that you're trying to make it say things it doesn't actually address). We were on the subject of *subsonic* L/D ratio - that VG wings can adapt their AR to flight condition is an advantage, not a drawback.
Again, all the benefits of relaxed stability could be applied to a VG wing configuration as well (do you think NATF & A/F-X would've been stable?), which would then perform even better at subsonic loiter than the conventional relaxed stability design - these are separate tools really that combine for added effect. As you say, the reason why it isn't done on the J-20 is that the "actual requirements" simply don't call for such good subsonic endurance, so the aircraft is fine without (and in fact better able to satisfy other, more pressing needs that favour low weight).
Sure - if you realize that the shock structure it generates will closely match the flow field used for streamline tracing the geometry, and that this flow field is a bog-standard cone or isentropic spike flow, you know that pressure recovery performance will resemble a conventional intake with a fixed external compression cone or isentropic spike. The weight and RCS advantages intuitively follow from the removal of the diverter, so you don't necessarily need to know about the design method for that, but it does inform your judgement on the resources required to successfully implement this design and whether these are lacking in Russia or not.
Doesn't matter how they addressed it - it is a more critical (due to being safety-relevant) challenge than DSI and they took it in their stride. You act as though seamlessly integrating TVC into the FCS for a function (artificial yaw stability, rather than just control and trim) which tolerates no failure is a trivial task. LEVCONs are not canards.
BTW, though we continue to disagree, thank you (seriously
) for dropping the petty nit-picking and sophistry - makes the exchange of views on-topic so much more pleasant.
Dizasta1
Senior Member
Su-57 is a class aircraft, with a great future ahead of it. It is a Russian aircraft (not Soviet and no it's not the same thing). People tend to forget that it's Russia which is facing sanctions. People also tend to forget that it's Russia which is developing the aircraft, not the Indians. Regardless of the historical ties between Soviet Union and India. It's not the same when dealing with the Russians. Indians need to get that through their head. There is no trust, and it's India, not Russia to blame for it. Traditional allies stay traditional, not bail out when it's convenient for them. For India it's more to do with their ethics in negotiating deals, it's dismal by all accounts. And with that much inflow of American military hardware entering the Indian military services. It seems justifiable for Russia to be cautious. Particularly when rumors spread regarding the Indian Kilo Class submarine being shown to the Americans. Even if it was a rumor, the damage is done and the trust has been tarnished. This is what happens when you play in the big league.
Recall the sale of Block-52 F-16s to Pakistan and Americans placing restrictions on where the aircraft would be based. Pakistan Air Force had to upgrade an FOB and convert it into a full fledged Air Force Base in Jacobabad. Just because the Americans didn't want the Chinese to access the aircraft. It's an F-16, not an F-22 Raptor. But hey, Pakistan went to great lengths to ensure the American concerns were dealt with.
J-20s are restricted to Chinese state, not allies or anyone else. F-22s are restricted to America, sales are prohibited to allies or neutral states alike. So why in the world would India go into a deal expecting an all access to a top of the line Stealth Fighter for Russia? They should thank their lucky stars that they'd even get these Stealth Sukhois, let alone have access to any source codes! That's a naive presumption, regardless of what deal they signed. And that's generally the problem with Indians, lofty dreams, sail so high that they forget what dry land looks like let alone have their feet planted firmly on the ground.
The French made it abundantly clear to the Indians that they had another thing coming if they thought that they could dump the responsibility of manufacturing on them. When the facilities would be constructed, managed and operated by Indians in assembling Rafales in-country. In the end, the $12 billion deal for 126 Rafales vanished into thin air and the Indians were left with 36 off-the-shelf Rafales worth a third the amount of the original deal. The French wanted the deal real bad, but even they weren't stupid enough to go blindly into a deal with the Indians.
Lies and deceit? We live in a world where big news networks with decades of credibility are lying outta their asses all day long. Politicians behaving like teenagers in the school yard.
Historically India has not had a good record in signing deals. For whatever reasons, be it their fault or the vendor country's. Either way it doesn't bode well for Indians. They suffer from a lack of cohesion and corruption within. So long as the house is divided on the inside, outsiders will always take advantage of it.
Recall the sale of Block-52 F-16s to Pakistan and Americans placing restrictions on where the aircraft would be based. Pakistan Air Force had to upgrade an FOB and convert it into a full fledged Air Force Base in Jacobabad. Just because the Americans didn't want the Chinese to access the aircraft. It's an F-16, not an F-22 Raptor. But hey, Pakistan went to great lengths to ensure the American concerns were dealt with.
J-20s are restricted to Chinese state, not allies or anyone else. F-22s are restricted to America, sales are prohibited to allies or neutral states alike. So why in the world would India go into a deal expecting an all access to a top of the line Stealth Fighter for Russia? They should thank their lucky stars that they'd even get these Stealth Sukhois, let alone have access to any source codes! That's a naive presumption, regardless of what deal they signed. And that's generally the problem with Indians, lofty dreams, sail so high that they forget what dry land looks like let alone have their feet planted firmly on the ground.
The French made it abundantly clear to the Indians that they had another thing coming if they thought that they could dump the responsibility of manufacturing on them. When the facilities would be constructed, managed and operated by Indians in assembling Rafales in-country. In the end, the $12 billion deal for 126 Rafales vanished into thin air and the Indians were left with 36 off-the-shelf Rafales worth a third the amount of the original deal. The French wanted the deal real bad, but even they weren't stupid enough to go blindly into a deal with the Indians.
Lies and deceit? We live in a world where big news networks with decades of credibility are lying outta their asses all day long. Politicians behaving like teenagers in the school yard.
Historically India has not had a good record in signing deals. For whatever reasons, be it their fault or the vendor country's. Either way it doesn't bode well for Indians. They suffer from a lack of cohesion and corruption within. So long as the house is divided on the inside, outsiders will always take advantage of it.