J-20... The New Generation Fighter

Re: New Generation Fighter

According to one of the FY post, saying Gaoshan said they are "unfinished" works (notice the lack of surface details and background?).

Re: New Generation Fighter

MwRYum said:

[video=youtube;uOOHTthSo3E]http://www.youtube.com/watch?v=uOOHTthSo3E[/video]
@0:23
Are we looking at the simulator with cockpit layout of the J-20?

Click to expand...

Could be a simulator -- but I think it was just a display for Zhuhai; more of a simulation of a potential next generation cockpit/technology demonstrator than a real simulator.

Roger604 said:

Gaoshan is known for leaking mysteriously accurate CGI. Although the actual J-20 did not look like his old 2004-ish CGI (may be original CAC proposal), I expect these will be proven accurate soon.

Looks to me like the canards, wings and vertical stabilizers are slightly trapezoidal, not straight or slightly swept. The second picture is interesting. The way the tail part goes apart from the engines suggests 3D TVC!!!

Click to expand...

I suppose these CGs are ones he only recently made?
It seems to be quite accurate with what we've seen so far. I'm interested in the shape of the wings and canards, to see the edge alignment and also the shape of the DSI intake. The CGs show them slanting "forwards" like the JF-17 or F-35 but most pictures we've seen seem to show it more like the F-22 only with DSI bumps.

Waiting for pictures of this thing in flight.

Re: New Generation Fighter

New pic of J-20, landing gears and equipment bay, etc:

Re: New Generation Fighter

ztz99g said:

I'll grant that the J-20 can perform SEAD under certain circumstances. In situations where a static target is being defended and the SAM batteries are immobile, SEAD can be performed without being lit up by enemy radars. In this case you just go over there and bomb a fixed location. This type of attack actually blurs the line between SEAD and Strike. Classic SEAD as performed by tag-teaming wild weasel and jammer aircraft is done versus mobile SAM units where you don't know their location and thus cannot fly under stealth to a specific location and take it out with a JDAM. The wild weasel serves as bait while trolling around in enemy airspace, when an enemy radar lights it up, the EA-6B trailing behind blasts noise, the weasel destroys the radar with a HARM or JSOW, next target.

Click to expand...

The Wild Weasel tactics you're describing is DEAD, not SEAD, and that's a meaningfull difference. In DEAD, the SAM site itself is your primary target, you want to degrade the enemy's AD capability for future operations. Here, you may need the enemy to light up. Maybe you can find his assets by other means, then just kill them out of the shadow with a stealth aircraft, it will also be easier for a LO plane to search. Or you provoke the SAM dude to light up with jamming, or a target aircraft, but the shooter can still be a stealth plane.
In SEAD, your intent is not to kill SAM sites, just to prevent them from interfering with you. So, if the guy doesn't light up because he fears detection, then fine, your SEAD mission was a succes. Or as soon as you spot a radar beam, fire an ARM, he'll swith off or be killed, either way, success.

Re: New Generation Fighter

plawolf said:

In trans and supersonic performance, I was referring to maneuverability. AFAIK, super maneuverability is as much (if not more so) about supersonic agility as it is about questionable low speed post-stall ability.

I fail to see how being longer would help the J20 in that department compared to, say, a similar design but made 10-25% shorter.

I actually don't think the J20 would have any chance of setting any fifth gen speed records unless it really does have a 'variable DSI'. One of the main disadvantages of DSI is the lower fixed max speed compared to traditional variable intakes.

I would say the the J20's range and sustained supercruise performance should be pretty awesome given its huge size. I would also it to have a very respectable internal payload, again due to its size allowing for potentially bigger and/or more weapons bays.

Its stealth and electronics are completely unknown factors are present.

Its agility is what I am most concerned about given how long it is, and the underpowered engines for now.

Its canard design should help, but that weakness may not even be fully addressed with the WS15 even if it meets its thrust requirement and also have TVC. But that is just a fear, it may turn out to be over stated. But we will have to wait and see.

Click to expand...

So much have been said about the subsonic limitation of DSI, I guess we'll have to hear from the real professionals, other than those internet armchair "experts", on whether there're ways to go around this limitation and whether the DSI inlet design can be optimised towards supersonic performance rather than just subsonic performance.

Re: New Generation Fighter

70092 said:

New pic of J-20, landing gears and equipment bay, etc:

Click to expand...

Thanks. So now we know that it's not the landing gear hatch that's hanging almost to the ground. Good to know!

Re: New Generation Fighter

Quickie said:

So much have been said about the subsonic limitation of DSI, I guess we'll have to hear from the real professionals, other than those internet armchair "experts", on whether there're ways to go around this limitation and whether the DSI inlet design can be optimised towards supersonic performance rather than just subsonic performance.

Click to expand...

This is a problem of all fixed inlet designs. A military plane operates in a great speedrange, and aerodynamic condition change greatly along those ranges, especially when going through the sound barrier. Of course a fixed DSI inlet can be designed to favor supersonic flight envelopes with a design aim of say M3. But that comes at the expense of dramaticly decreasing slow speed performance, since the engine won't have enough air anymore. At some point slow speed flight / take off performance will be so bad the whole thing isn't usefull anymore.
Well, thinking about it, it may be possible though to have extra doors installed on the side / top or so of the intake cover that open in the slow speed regimes to allow extra airflow. Like in the Tornado, or the MiG-29 that totally closed the regular intakes for take off.

plawolf said:

I'm not yet entirely convinced on the arguments about better trans and supersonic performance. Maybe if someone who supports that view could better explain how being longer helps, I might change my mind.

Click to expand...

There's this thing called the area rule. Especially in the transsonic regions a body with a certain shape has the least drag. That body looks like a cigar, but pointed towards the ends. Length and diameter are in a certain relation, since the smoother the diameter / shape change over length, the better the airflow. So to put more volume inside a body, or just make it wider, it has to become longer to maintain the same aerodynamic properties in that regard.

That is probably not the whole truth the planes length, but I guess at least part of it.



I'm sure internal fuel load, hence range is also a factor. And, seeing the shape, maybe the engeniers indeed managed to put a big, continuous weapons by into the fuselage. Not big enough for real AShM, but for some AGM at least.

Re: New Generation Fighter

Quickie said:

So much have been said about the subsonic limitation of DSI, I guess we'll have to hear from the real professionals, other than those internet armchair "experts", on whether there're ways to go around this limitation and whether the DSI inlet design can be optimised towards supersonic performance rather than just subsonic performance.

Click to expand...

I thought the point of a DSI was that it provided adequate airflow for speeds up to mach 2 without moving parts? In any case, because the DSI is just a bump that's designed to block unwanted boundary layer airflow, couldn't the bump be designed differently to do this job for different speeds?

EDIT:Question answered.

Re: New Generation Fighter

latenlazy said:

I thought the point of a DSI was that it provided adequate airflow for speeds up to mach 2 without moving parts? In any case, because the DSI is just a bump that's designed to block unwanted boundary layer airflow, couldn't the bump be designed differently to do this job for different speeds?

EDIT:Question answered.

Click to expand...

That's what I meant by the DSI being optimised for supersonic speed. And maybe I should add: without affecting adversely the subsonic airflow. What I'm interested to know is whether they have found a way to go around the problem.

Re: New Generation Fighter

plawolf said:

Yes, all correct and all very basic stuff, but none of it addresses my question of why do you think stealth aircraft cannot engage in SEAD missions in its entirety (with the right weapons load of course).

Click to expand...

I just pointed out scenarios in which stealth aircraft cannot engage in SEAD missions in its "entirety". If you can't read that's not my fault.

plawolf said:

Do you even understand how stealth fighters work? Doesn't seem like if from your post.

Click to expand...

This is a fairly stupid question. I'll not answer it except to point out its stupidity.

plawolf said:

'Fly under stealth to a specific location'? What is that supposed to mean? This is not Star Trek where you say 'its a good day to die' and actually have to switch on a cloaking device you know. Your fighter is stealthy no matter where you fly it.

Click to expand...

Again, your pathetic attempt at derision merely belies your own ignorance. When I say fly under stealth, I don't mean it gets turned on like a cloaking device. That's moronic to even suggest and betrays straw man stupidity on your part. I mean to say that stealth is never all aspect. If you have known radars emitting with known detection ranges against certain RCS's you will have to navigate a certain course and fly a certain way through enemy territory. A radar with a detection range of say 30km against your frontal RCS may suddenly become 200km against your underbelly RCS as you bank during a turn on your route. But oops, you are only 160km away from the radar. You are suddenly in deep shit as two dozen enemy fighters scramble to your general vacinity. The F-22's software was developed with the ability to calculate all these variables and can plot the most stealthy course through enemy terrain. That's flying under stealth. Get a clue.

plawolf said:

Also, do you understand why current SEAD/DEAD aircraft NEED support from dedicated jamming aircraft support now, and how that requirement for dedicated jamming aircraft could easily be completely eliminated with stealth?

Click to expand...

WTF are you talking about? If the enemy doesn't have the first clue that you are there, they will not be turning on their illumination radar. You will also not know that they are there. That means the first 4th generation bombtruck that you subsequently send through the area because you think you cleared the zone is going to get shot down in flames. Oops, missed a SAM or ten, didn't we?