Shenyang FC-31 / J-31 Fighter Demonstrator

SteelBird

Colonel
I moved back a few pages and didn't see anybody posting this video. So I post it here.

[video=youtube;lS9GSVGO7yo]http://www.youtube.com/watch?v=lS9GSVGO7yo[/video]
Vow, look like it was a rather large convoy and is a harder evidence that this is a real thing, not a mock-up or a theme park model.
 
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Quickie

Colonel
The use of 2 smaller engines rather than one larger engine fits more naturally into the usually flat frame of a stealth fighter. Both the J-21 and F-35 would have to sacrifice some aerodynamics performance in exchange for incorporating stealth into the design but I would say that the J-21 have the advantage of a basically stealthier shape to start with.

We've heard that the F-35 is designed to have a single engine because it is intended to have VSTOL in one of its variant. Question is would it be that difficult for a twin engined fighter to have VSTOL capability?
 

paintgun

Senior Member
thinking about China military aviation engine development lines, it became apparent to me that the previous info by pupu and other mainland big shrimp said about this SAC prototype does make some sense, let's crudely divide it this way :

1. SAC lineage PLAAF/NAF fighter, current : J-8, SinoFlankers, J-11A/B/BS/J-15 with WS-10
will be superseded by ?
future engine : WS-15?

2. CAC lineage PLAAF/NAF fighter, current : J-7, J-10A with WS-10
will be superseded by J-10B
new line : J-20, J-2X?
future engine : WS-15?

3. export lineage : Q-5, J-7, JF-17, K-8

4. trainer lineage : JJ-7, K-8
will be superseded by JL-9 and L-15

5. Xian lineage

-------------

if we look at the export lineage, it is dominated by CAC and other companies, but almost no export success from SAC
looking at the engine class rumor, this bird falls perfectly into the export lineage category, and another new class category with no existing player which is the carrier aviation category
so it makes perfect sense for SAC to make an effort on export market, to aim at profitability and also to aim at the carrier aviation, the existence of the J-15 does not necessarily mean that it will be the only carrier based fighter to be deployed by PLAAF

the WS-13 engine class also means, that this prototype cannot be SAC's successor to the heavy J-11 lineage without relinquishing Shenyang's control on engine production
should there be continuation of pitching effort by SAC for PLAAF 5th gen bid as a cheaper tandem solution, we will see some kind of revelation later on

which kinda bring a new question for WS-10's fate after the J-10 and J-11 era, but that's for another topic to discuss
 

delft

Brigadier
The use of 2 smaller engines rather than one larger engine fits more naturally into the usually flat frame of a stealth fighter. Both the J-21 and F-35 would have to sacrifice some aerodynamics performance in exchange for incorporating stealth into the design but I would say that the J-21 have the advantage of a basically stealthier shape to start with.

We've heard that the F-35 is designed to have a single engine because it is intended to have VSTOL in one of its variant. Question is would it be that difficult for a twin engined fighter to have VSTOL capability?
Your right Quickie, stealth aircraft need to have two engines. Having only one engine compromises the F-35. But the Marines are forced to operate from flattops without cats or ski ramps and without traps. And designing an aircraft for them alone would result in planes that would cost much more than those for Air Force or Navy, perhaps even a little more than the F-35B will cost ( but perhaps a little less! ).
 

kyanges

Junior Member
There doesn't seem to be any reason why a single engine plane would be any less stealthy than a 2 engine one. Nor do 2 engines seem any more "natural" a fit for a stealthy airframe than one.
 

Air Force Brat

Brigadier
Super Moderator
If and CAC develops their medium weight 5th gen, things will get really interesting.

I would expect CAC's medium weight to be single engined so that it would share the same powerplant as the J20 for logistical savings as well as because of CAC's experience with single engined types like the J10 and JF17.

I can see the PLAN preferring the twin engined approach for added safety, while the air force might prefer the logistics savings from having a common engine.

That is, of course assuming that CAC does come up with a medium weight 5th gen. CAC is very capable, but just looking at the sheer number of projects they have running, and it might be a case of project overload for them.

In addition, I have long held reservations about whether it is necessary or even wise at all for the PLAAF to follow the American model and go all fifth gen.

I think it would be much better for the PLAAF to just have the J20 as it's only fifth gen fighter, and buy them in decent number as opposed to what happened to the poor F22.

For the strike role, I think a J20 sub-variant with twin seats, larger and deeper weapons bays for heavy ground attack munitions like what the FB22 was to the F22 would be perfect.

For the PLAAF's future lo-end fighter, a J10C with WS15 engines and redesigned fuselage should be a step up from the likes of the Typhoon and Rafale and be more than enough to meet the PLAAF's needs.

This SAC design would serve as the PLANAF's future carrier fighter to serve alongside the J15, and also act as China's export fifth gen while the J20 is kept strictly off limits.

If this is how it works out, it would be quite amusing actually. Because I think it is almost a certainty that this SAC 5th gen will use the WS13 engine as it's powerplant, thus the arch rivals at SAC and CAC would actually present a high-lo mix of the J21 and JF17 that would actually work extremely well as a pair.

Thank you Wolfie for your sympathies for our poor, lovely, dearly departed F-22!

---------- Post added at 12:49 AM ---------- Previous post was at 12:43 AM ----------

Even better :p :p

Well, an obviously attractive chick if I ever saw one, to say she reminds me of someone I once knew begs the question?

---------- Post added at 12:52 AM ---------- Previous post was at 12:49 AM ----------

There doesn't seem to be any reason why a single engine plane would be any less stealthy than a 2 engine one. Nor do 2 engines seem any more "natural" a fit for a stealthy airframe than one.

Well, when you have TVC as on the Raptor, that is definetly a stealth enhancer when you can use that for roll, or pitch, without control surface deflection flapping around out in Radar world, and it also is more along with the design philosophy of the fifth gen in general, which was and is to be max performance.
 

Quickie

Colonel
There doesn't seem to be any reason why a single engine plane would be any less stealthy than a 2 engine one. Nor do 2 engines seem any more "natural" a fit for a stealthy airframe than one.

What I meant by fitting naturally is fitting within the airframe without causing any or too much protrusion. Most of the stealth airplanes, in fact all of them, have a flatter airframe when compared to non stealthy airplanes. It's possible to fit the single engine within the airframe by reducing the size of the engine but this would also mean a reduction in power below the requirement. The other option is to build a stealth jetfighter with a more squarish cross section but this doesn't seem really feasible since we've yet to see one in action.
 
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Mysterre

Banned Idiot
I moved back a few pages and didn't see anybody posting this video. So I post it here.

[video=youtube;lS9GSVGO7yo]http://www.youtube.com/watch?v=lS9GSVGO7yo[/video]
Vow, look like it was a rather large convoy and is a harder evidence that this is a real thing, not a mock-up or a theme park model.
Sounds like the loudhorn is telling them not to take photos, but they do it anyway lol
 

jobjed

Captain
What I meant by fitting naturally is fitting within the airframe without causing any or too much protrusion. Most of the stealth airplanes, in fact all of them, have a flatter airframe when compared to non stealthy airplanes. It's possible to fit the single engine within the airframe by reducing the size of the engine but this would also mean a reduction in power below the requirement. The other option is to build a stealth jetfighter with a more squarish cross section but this doesn't seem really feasible since we've yet to see one in action.

Do you think it'll be possible to fit weapon bays to the side of the engines and having nothing underneath it in order to make the airframe 'stealthy'? I think that could be a good compromise between armament, single-engine and aerodynamics.
 

kyanges

Junior Member
What I meant by fitting naturally is fitting within the airframe without causing any or too much protrusion. Most of the stealth airplanes, in fact all of them, have a flatter airframe when compared to non stealthy airplanes. It's possible to fit the single engine within the airframe by reducing the size of the engine but this would also mean a reduction in power below the requirement. The other option is to build a stealth jetfighter with a more squarish cross section but this doesn't seem really feasible since we've yet to see one in action.

I'm not trying to counter your statements, but I am having a hard time understanding just what the problem is. I can't think of a single reason why there would be any more protrusions from a plane with a single engine than with two. Why would the single engine have to be reduced in size?

Maybe an image or something would help me understand. I apologize in advance if it's something terribly obvious that I'm missing. That's happened more than a few times...
 
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