The problem is of course no one is going to give up the capability. I would expect there would be more test like that, and yes more debris.

One cannot improve the weapon or capability without having more tests.

The Su-57 is a Heavy Fighter correct??? :rolleyes:

So, is closer in size and role to the F-22 or F-35??? 😉

Eh, Well i merely state that your obsession toward J-31 is because it’s closer to US designs. :highly_amused: I wonder if it’s true.

As much as i want it to be as what the journo might drive us there. I found that hyping something that has no specifics inside it to be of no wise movement. I’m more than happy if proven wrong.

So how do i view Izd-30 ? It is a more reliable, advanced variant of Izd-20 with reduction in IR signature as evidently seen in flight prototype but internally it will be closer to PW-F-119.

It doesn’t really matter, since it is the designer itself who is making the claim and he probably knows how such comparison needs to be done:

[I]The engine of the second stage for the su-57 the developers have applied a number of new design approaches and technologies, thanks to which “article 30” in the specific fuel consumption approximately corresponds to a turbofan engine AL-31F (670 grams per kilogram-forces per hour in cruise mode), but surpasses it in terms of the specific thrust.

Is this stated by the designer or it’s the explanation from the journalist ?

“Specific fuel consumption opposes with a specific thrust. The best fuel consumption is obtained on civil turbofan engines, but they have the least specific thrust due to high bypass ratio. At one-loop engines — on the contrary, specific thrust is high and consumption is high. Through the use of new designs and technologies in the “Product 30” specific consumption remained at the same level, but the specific thrust increased“, — said Marchukov.[/I]

The thing is at what condition and speed.

Su-57 has a cross-sectional area very slightly bigger than F-22. To supercruise in analogous conditions* it would need, but for very different aerodynamic merit figures (which is unlikely) roughly the same amount of thrust, estimated at ca. 11000 kgf per engine in dry settings (of course in bench not at altitude). AL-41F1 generates only 8800 kgf in dry settings, that means F119 has 25% more thrust. Do you think that, just by redesign and slight improvements in technology (AL-41F1 is already very modern by most standards and generates 2.5 tons thrust more than AL-31F) from better compression or higher combustion temperature they can get the same SFC that AL-31F and the same dry thrust that F119, all at the same time? This doesn’t look likely to me and variable bypass ratio seems a distinct possibility to achieve that result, but maybe I am wrong.

* This assumption can be questioned of course, but:
> You generally don’t create your answer to an existing foreign design to be inferior from the onset, that would make no sense
> From other parameters we know the F-22 was taken as reference, as it would be obvious in any case
> From the plane’s patent we know the focus on supercruise is one of its main design drivers

So I think the assumption similar levels of thrust are needed is not so far fetched.

The thing is that there are no real mention of Variable cycle technology being used in Izd-30. The journalist doing the interview in other hand want us readers to believe otherwise.

How do you reconcile the supercruising design with a SFC like the one of AL-31?

What condition ? and what altitude ? Remember SFC is not a constant value. Value you got on bench test may not be the one you got during flight.

That is perfectly fine. But the quote says the 5G engine differs from 4G in having variable bypass and 6G adds a third stream. That or the machine translation is kidding me. There can be misreporting, misinterpretation and whatever, but the statement looks clear and consistent with the rest of the article and other related statements.

He isnt really specific on the matter. First he talked about Product 20. The AL-41FU in 1990’s as the 5th generation engine, then goes to describe product 30 as “Gen 5++” . And then the one you quoted which “5th gen engine needs VCE” No specific mention of Izd 30 of being a variable bypass engine.

F119 vs. AL-31F. Engines for supersonic flight have (normally) lower BPR. At the time of MFI it was already clear for the Soviet designers that a 5G engine needed to be VCE. I doubt they have changed their minds, they are insistent on Izd. 30 being a REAL 5G engine. So to me it makes sense but I can be perfectly wrong. We will see, I hope.

They are by default a low bpr engine. But basically shows that you can into super cruise without actually need to do Variable bypass. As much as i want to be Izd 30 to be Variable bypass as GE-F120. I dont see hyping about Izd-30 have such feature as a wise decision.

I encourage you to read again. For the future he mentioned the 3rd stream engine. That doesn’t mean the current one is not a VCE with two streams, does it?

I’m sticking with Flateric at this one.

True, but can an engine with BPR = 0.3 have the same SFC than an engine with BPR = 0.60? I stand to be corrected but this doesn’t sound realistic to me.

Which engine you are talking about ?

Well it’s because J-31 look closer to US approach. XD