Russian requirements?
There are serious reasons to believe what su-57 is capable of mach 2.6 dash(canopy material choice strongly suggests it), and quite possibly higher than Raptor supersonic cruise speed.
Russian Su-57 Aircraft Thread (PAK-FA and IAF FGFA)
- Thread starter A Bar Brother
- Start date
There are serious reasons to believe what su-57 is capable of mach 2.6 dash(canopy material choice strongly suggests it), and quite possibly higher than Raptor supersonic cruise speed.
My argument was about what it means regarding requirements. Similarly, selecting the lowest-AR option in section 5 shows how little priority was accorded to subsonic loiter and because high aspect ratio confers a much better L/D-ratio at subsonic speed than a highly swept wing, VG wings are an extremely effective way of providing good endurance in a supersonic aircraft. That (modern) fighters don't have them is a reflection of their requirements giving greater importance other things, not of vortex lift being better for loiter.
As for relaxed stability, VG wings and relaxed stability aren't mutually exclusive. Hell, the F-14 actually implements an early "poor man's relaxed stability" with its glove vanes (although the lack of a FBW system for artificial stabilization means it's never genuinely unstable - use and benefit are limited to supersonic flight).
Knowing it allows you to be aware of what its advantages and drawbacks are. For example that pressure recovery is unremarkable, so if your application calls for very good pressure recovery over a wide range of Mach numbers, you're therefore better off with a variable geometry intake. It also enables you to have a realistic notion of the resources it takes to implement a DSI design and judge whether claims that it's somehow too challenging for Russia are credible - which they are not.
I would agree with that. The variable inlet is obviously better suited to the requirements of the Su-57, however.
You mean in the same way as they didn't test fly a variable caret intake before, or LEVCONs, or an aircraft with such a high degree of yaw instability? Or in the same way as China hadn't test flown a DSI themselves before they first used it on the JF-17? Come on.
JF-17 was not an important fighter for PLAAF and they didn't order any. It doesn't have anywhere near the prestige and importance to respective airforce as Su-57. It's unlikely the Russians will test DSI on such an important fighter program as their first actual real life test. Only after the Chinese understood DSI well enough and had first hand experience of its attributes, did they place it on J-10 and J-20. There is pretty good reason to consider DSI as the best choice for intakes with today's technology. Why else will the latest US and NATO 5th gen fighter (keep in mind that F-22's ATF program was started in the 90s and well before any comprehensive testing and prototyping of DSIs have been done) be using it along with both Chinese 5th gen fighter and prototype. Both USA and China have decades of experience and many different platforms of variable geometry intakes. If it were truly better to use variable geometry intakes, why would both countries use DSI on both their latest fighters? It stands to reason there's more to it than the doubters think. They may think they know a few things but they are FAR from experts and don't work for either LM or CAC.
US and Russia does, yes. Decades.
China is by no means any "US and China decided" aircraft design powerhouse like many tend to write it here. May as well write "US decided".
Decided for a joint strike fighter, designed to work under f-22 umbrella against any peer opponent.
Maybe.Europeans decided what J-10 like upgrade doesn't worth associated performance drop.
Russia designs slightly faster aircraft. Which actually leaves China alone in making DSI-equipped air superiority platforms. Maybe decades of experience with j-8 shaped this opinion, I don't know.
I have ask https://www.sinodefenceforum.com/ru...ak-fa-and-iaf-fgfa.t7155/page-238#post-491795
but no answer have you some Turn radius also Climb rate eventualy he is new surely difficult and mach 2.6 really ? for see if the dogfighter is good
China is an aircraft design powerhouse today. It is one of five or so nations capable of design to any significant scale and variety. You show your dislike of the idea of China being capable in any way. Yes, today it cant match USA that's for sure. But matching Russia?? too easy already. Maybe even at parity in design today let alone in future. Not so much in engines though. It's easy to say forum members think too highly of China's aerospace design abilities. Where's your evidence? China has civil programs that seem to be working out for initial trials. Lot's of UAV designs and military aviation designs. Reverse engineering is strong. Innovation is just starting but the funding, academics, infrastructure, and tools are all there. What is needed now is time to develop all this. When the soviets got their hands on Nazi material and engineers, Jewish talent, and poured massive funds into high technology, they still struggled and failed again and again. People are rarely aware of the MASSIVE failures of Soviets despite all the advantages. Now Russian aviation industry is still strong thanks to the advances made then. All of this takes time and China now has the material to improve. Already it is a player in almost every aspect of this industry. Now what makes you think China is not the powerhouse some people think it is. Who are these people and what EXACTLY did they say to make you think they are too confident in China's abilities? Or is it just your personal discomfort in people seeing some promise in China's abilities today and promising future?
Both China and USA are using DSI intakes in both their latest fighters. This shows that DSI certainly has great advantages over previous conventional designs. Russia wanted speed and kinematic performance and Sukhoi's choice of design and intakes reflect this. This doesn't necessarily mean they are not capable of designing a DSI intake for Su-57. This is not my belief. But it CAN mean this. Whatever it is, DSI seems to be a good choice of intakes otherwise why would both USA and China (you seem to interpret this as China being in USA leagues and that somehow offends you which is why you wrote what you did... so silly because it doesn't but logic ain't your strong point) use this intake? I'm sure Sukhoi's choice suits the Su-57 just fine. Comparing apples and oranges here. Who knows how effective Su-57's approach is compared to F-22 and J-20's (J-20 follows the American method... perhaps you prefer the term, copies).
Both China and USA are using DSI intakes in both their latest fighters. This shows that DSI certainly has great advantages over previous conventional designs. Russia wanted speed and kinematic performance and Sukhoi's choice of design and intakes reflect this. This doesn't necessarily mean they are not capable of designing a DSI intake for Su-57. This is not my belief. But it CAN mean this. Whatever it is, DSI seems to be a good choice of intakes otherwise why would both USA and China (you seem to interpret this as China being in USA leagues and that somehow offends you which is why you wrote what you did... so silly because it doesn't but logic ain't your strong point) use this intake? I'm sure Sukhoi's choice suits the Su-57 just fine. Comparing apples and oranges here. Who knows how effective Su-57's approach is compared to F-22 and J-20's (J-20 follows the American method... perhaps you prefer the term, copies).
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Mach 2.6 is not climb rate. That would be insane. Su-57 should easily reach M2.6 high altitude horizontal speed. Even 27 can do at least M2.5 top speed.
Yet they did implement technologies on it as their first actual real life test which carry a lot more risk than an intake design the defining characteristic of which is its elegant simplicity and the challenges of which lie in areas which Russia has particularly strong capabilities in. That they would have shied away from using DSI if it was the best solution to their requirements just doesn't pass the sniff test, which indicates their needs were such that a different solution was preferable on merit.
There you go - requirements
The jury is out on whether that's a smart design emphasis, but it is what it is.Su-27 family is Mach 2.35 tops.
I'm a bit skeptical about the rumours about the Su-57 really being capable of Mach 2.6, as there are official comments which state the "speed requirement" (but did that really refer to the *top* speed specification or something else?) was reduced to Mach 2.0. It would definitely explain a LOT of peculiarities in the aircraft's configuration which would otherwise be rather odd (among which is the choice of intake type, no doubt) though, so I'm on the fence.
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