J-XY - maybe J-35 - next generation carrier-borne fighter


latenlazy

Colonel
My read is canards will remain a Yang Wei-specific feature, or from the chief designer tree of Song (like the coach tree in pro sports). They are not a feature to compensate for something, like the small canard on Su-30MKIs, but an integral part of the overall aerodynamic and therefore engraved in the flight control software. By removing the canards they need to move the wings forward, and that is a complete redesign.
They wouldn’t need to move the wings forward if they inserted the canards where the LERXes were like with the Su-33/J-15, which is what I assumed the “rumour” was talking about before I realized I had misread (the rumour makes no mention of canards). I originally thought the source was talking about a triplane configuration, because it also mentioned tailplanes, and a triplane might’ve made sense if they wanted the fighter to be ski jump capable and needed some extra lift at low speeds.
 

kurutoga

Junior Member
Registered Member
They wouldn’t need to move the wings forward if they inserted the canards where the LERXes were like with the Su-33/J-15, which is what I assumed the “rumour” was talking about before I realized I had misread (the rumour makes no mention of canards). I originally thought the source was talking about a triplane configuration, because it also mentioned tailplanes, and a triplane might’ve made sense if they wanted the fighter to be ski jump capable and needed some extra lift at low speeds.
My point is, if they do not like canards, they would not pick Song/Yang as the chief designers. It is that simple. With Song/Yang being the final decision makers, you get J10/J20 type of frames. Canards are a permanent and important feature, not a complement to be removed once you have a bigger engine or TVC (as in Su30's case).
 

latenlazy

Colonel
My point is, if they do not like canards, they would not pick Song/Yang as the chief designers. It is that simple. With Song/Yang being the final decision makers, you get J10/J20 type of frames. Canards are a permanent and important feature, not a complement to be removed once you have a bigger engine or TVC (as in Su30's case).
It depends on why the canards are added into a design. If they're primary control devices, then of course they're integral. If they're control devices added to meet a specific requirement (like sky jump take off), then they can be expendable. For example, the J-15 has canards, but it technically doesn't need them for most of its flight envelope. The canards are primarily for short take off from a ski ramp. If the J-15 could meet the same takeoff requirements with a more powerful engine or TVC deleting the canards isn't an unthinkable possibility.

If we're going to talk about the Su-30MKI, we can actually contrast it with the development of the Su-35. Sukhoi started off with a variant of the Su-35 that had both canards and TVC, but during development they realized they could achieve the same maneuverability gains with just TVC and an improved FCS, so they deleted the canards in the final production version. This wouldn't be possible with the J-20, Eurofighter, Rafale, etc because the canards are primary control devices in those designs, but in Flankers the primary control devices are tailplanes, and the canards are auxiliary. I assumed in the case of an upsized J-31 variant, if they were adding canards to make a triplane design it would be mainly for ski jump take offs. I was suggesting that this might be a suboptimal compromise that could be revised later. Of course, this is a moot point of discussion, because the rumour neither mentions canards or ski jump takeoffs (the former of which was a misread and the latter which was derived from trying to deduct the reasoning behind the former).

Though, I'm not entirely sure we're having the same conversation. The rumour in discussions says SAC's submission won, and Song Wencong and Yang Wei aren't with SAC...they're with CAC. The design in discussion isn't the J-20, as made clear by both the comment that it's basically an upsized J-31 and that it has folding tailplanes.
 

kurutoga

Junior Member
Registered Member
It depends on why the canards are added into a design. If they're primary control devices, then of course they're integral. If they're control devices added to meet a specific requirement (like sky jump take off), then they can be expendable. For example, the J-15 has canards, but it technically doesn't need them for most of its flight envelope. The canards are primarily for short take off from a ski ramp. If the J-15 could meet the same takeoff requirements with a more powerful engine or TVC deleting the canards isn't an unthinkable possibility.

If we're going to talk about the Su-30MKI, we can actually contrast it with the development of the Su-35. Sukhoi started off with a variant of the Su-35 that had both canards and TVC, but during development they realized they could achieve the same maneuverability gains with just TVC and an improved FCS, so they deleted the canards in the final production version. This wouldn't be possible with the J-20, Eurofighter, Rafale, etc because the canards are primary control devices in those designs, but in Flankers the primary control devices are tailplanes, and the canards are auxiliary. I assumed in the case of an upsized J-31 variant, if they were adding canards to make a triplane design it would be mainly for ski jump take offs. I was suggesting that this might be a suboptimal compromise that could be revised later. Of course, this is a moot point of discussion, because the rumour neither mentions canards or ski jump takeoffs (the former of which was a misread and the latter which was derived from trying to deduct the reasoning behind the former).

Though, I'm not entirely sure we're having the same conversation. The rumour in discussions says SAC's submission won, and Song Wencong and Yang Wei aren't with SAC...they're with CAC. The design in discussion isn't the J-20, as made clear by both the comment that it's basically an upsized J-31 and that it has folding tailplanes.
The basic design of J10 and J20 was based on Song's paper, not just the wing (shape, size, position, thickness), canards, but also the "wing LE fillet". In this system canards is the basic design feature. Canards were specifically chosen due to advantages in some scenarios especially at high angle of attack. Yang added DSI but this is a complete system. I don't think you can just remove the canards that easy and retain the same flight characteristics.

The Su30 canards (only in some models) were added as an afterthought to address a problem. IMO these two situations are of different nature.
 
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latenlazy

Colonel
The basic design of J10 and J20 was based on Song's paper, not just the wing (shape, size, position, thickness), canards, but also the "wing LE fillet". In this system canards is the basic design feature. Canards were specifically chosen due to advantages in some scenarios especially at high angle of attack. Yang added DSI but this is a complete system. I don't think you can just remove the canards that easy and retain the same flight characteristics.

The Su30 canards were designed as an afterthought to address a problem. IMO these two situations are of different nature.
I wasn’t talking about deleting canards from the J-10 or J-20 though.
 

jobjed

Captain
The basic design of J10 and J20 was based on Song's paper, not just the wing (shape, size, position, thickness), canards, but also the "wing LE fillet". In this system canards is the basic design feature. Canards were specifically chosen due to advantages in some scenarios especially at high angle of attack. Yang added DSI but this is a complete system. I don't think you can just remove the canards that easy.

The Su30 canards were designed as an afterthought to address a problem. IMO these two situations are of different nature.
That's exactly what he said.

You can't remove canards from J-20 but you can from the J-15.
 

Iron Man

Major
Registered Member
The part I don't understand is the timing. If the new jet is optimized for ski-jump, it is near sighted. If it is optimized for catapult, it is too early. For both? it is a waste.
You push a non-existent dichotomy. A catapult fighter can already take off from a ski ramp. "Optimizing" a fighter for ski ramp take-off is both unnecessary and short-sighted, so no, nobody is going to optimize any fighter for a ski-ramp takeoff, especially one that is coming out in the next several years.
 

by78

Brigadier
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"Key points: Shenyang won the winning ribbon carrier machine. Rhombic chicken, foldable main wing, double hair WS19. Head and tail like 20, chicken wings to enlarge the area, the main wing and the tail can be folded, DSi Inlet, supersonic cruising capacity of not less than half an hour. Basically in the 30 ton level. In fact, it's a 31 enlarged version."
划重点:沈阳中标丝带舰载机。菱形鸡头,可折叠主翼,双发WS19 。头和尾像歼20,鸡翼面积进行放大,主翼和尾翼可以折叠,DSI进气道,超音速巡航能力不低于半个小时。基本上在30吨级左右。其实就是31的放大版。

(The post contained/quoted another post that is now deleted. If anyone saw it, let us know what it said.)
Does it say there are canards (chicken wings)? How does "head and tail like J-20" and (possibly) canards go with enlarged FC-31?
I don't think the Weibo user you are quoting is all that credible, unless he's repeating something said by a big shrimp elsewhere. He certainly doesn't have a track record to speak of, except for being a military fan.
 

SinoSoldier

Colonel
The part I don't understand is the timing. If the new jet is optimized for ski-jump, it is near sighted. If it is optimized for catapult, it is too early. For both? it is a waste.
You do realize that CATOBAR-compatible aircraft can operate from ski jumps, right?
 

SinoSoldier

Colonel
I don't think the Weibo user you are quoting is all that credible, unless he's repeating something said by a big shrimp elsewhere. He certainly doesn't have a track record to speak of, except for being a military fan.
Interestingly Huitong is repeating the same thing and has been doing so for the past few days.

"The latest rumor (January 2018) claimed that 601/SAC is working on an enlarged carrier-based variant based on FC-31, powered by two WS-19 turbofans. Its MTOW is >30t."
 

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