Shenyang / Chengdu 6th Gen Demonstrators?

Josh_TN said:
It seems perfectly reasonable to me that “J-36” would need three engines for any decent high speed performance if J-20 already requires two. There still would likely be extra electrical power production associated with a three engines propulsion arrangement, but the main landing gear clearly indicates a very heavy MTOW and from what I understand delta wing configurations do not lend themselves to short take off runs as it is.

Simplest answer: off the shelf engines from the J-20 are being used to achieve necessary thrust because no engine that can support the requirements in a twin configuration exists. Given the protracted development of various PLAAF engine projects (Russian engines were initially used on Y-20, J-20, and H-6K and still are on the latter AFAIK), this seems perfectly reasonable. As posted above, it is unusual and comes with some maintenance complexity but makes for a simple and immediate solution for desired thrust levels.
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Help me understand:
AirplaneWeight-GROS (kg)Weight-MAX (kg)Engine TypeThrust-MIN (kN)Thrust-MAX (kN)NumberThrust-TOT-MIN (kN)Thrust-TOT-MAX (kN)Ratio GROSS-MIN (kN/kg)Ratio MAX-MAX (kN/kg)Max V (km/h)
XB-70242,536245,847GE-YJ-938912065347200.002200.002933,310
J-3645,00054,000Shenyang WS-15161.861802323.723600.007190.00667??
SR-7168,94678,018P&W J-58111151.242222302.480.003220.003883,540

I know there is more to this than pure thrust to weight ratio but why would J-36 not be able to achieve performance needed with two engines?

Mind you, I am a newbie with this and have no experience. Just crunching numbers...
 
6footboy said:
Help me understand:
AirplaneWeight-GROS (kg)Weight-MAX (kg)Engine TypeThrust-MIN (kN)Thrust-MAX (kN)NumberThrust-TOT-MIN (kN)Thrust-TOT-MAX (kN)Ratio GROSS-MIN (kN/kg)Ratio MAX-MAX (kN/kg)Max V (km/h)
XB-70242,536245,847GE-YJ-938912065347200.002200.002933,310
J-3645,00054,000Shenyang WS-15161.861802323.723600.007190.00667??
SR-7168,94678,018P&W J-58111151.242222302.480.003220.003883,540

I know there is more to this than pure thrust to weight ratio but why would J-36 not be able to achieve performance needed with two engines?

Mind you, I am a newbie with this and have no experience. Just crunching numbers...
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I am not an engineer and I do not know the project requirements, but I would assume aerodynamics of the aircraft play a very significant role on cruise speed (and other requirements) in addition to weight and thrust ratio. In terms of drag “J-36” is no SR-71. IIRC even F-105s could “supercruise” in the sense of maintaining super sonic at dry thrust. X-51 could maintain hypersonic speeds with a trivial amount of thrust that was not 1:1 if I recall. Also it is worth noting that of the two aircraft you posited, one was a special project that flew from secluded bases with rather long runways for special purposes and the other never entered service. Their engine design was also completely different, so I think a thrust comparisons are probably inconclusive - at what altitude and speed? Finally, our “J-36” numbers are speculative at best.
 
paralay said:
Everything has been done for you and with more precise numbers ;)

table-eger
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Excellent. Much better indeed. My question remains. Why would J-36 require a 3rd engine for additional performance (two engine performance seems to be quite good for a 55,000 kg plane)? Why that engine cannot simply be an electrical generator in its primary function? Especially since the 6th generation is so power hungry (radar, processing power, laser-based weapons)?
 
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FighterJock said:
Yet an other Shenyang fighter GTX? That is a surprise that I was not expecting.
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It's most likely a CCA that a few credible PLA watchers have been hinting at(Tea cups and Tea set analogy) and not the actual Shenyang fighter imo, 15 meters length is too small for it to be the aircraft flown with the J-16 last year.
 
Thanks Tomboy, a CCA type unmanned fighter would obviously complement both the J-36 and the J-50 and that would be a smart move by the PLAAF. But just how big would such a CCA fighter be?
 
Might be a silly idea but lets say that you want to test out a mix of different engine types? Maybe you could make a couple test articles that have something like two turbofans and some experimental ramjet or detonation engine?
 
TMA1 said:
Might be a silly idea but lets say that you want to test out a mix of different engine types? Maybe you could make a couple test articles that have something like two turbofans and some experimental ramjet or detonation engine?
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The airframe isn't meant to be flown that fast also like the top intake is apparently a DSI which doesn't work well with ramjets that require a supersonic inlet airflow. IMO, J-36 having a ramjet or RDE just makes no sense for combat effectiveness especially when those engines also cannot generate any electricity due to lack of a turbine section.
 
Tomboy said:
The airframe isn't meant to be flown that fast also like the top intake is apparently a DSI which doesn't work well with ramjets that require a supersonic inlet airflow. IMO, J-36 having a ramjet or RDE just makes no sense for combat effectiveness especially when those engines also cannot generate any electricity due to lack of a turbine section.
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Can we can back to reality?? J-36 won't have a ramjet engine anytime and even lesser has now! All three engines are the same and are most likely WS-10C/WS-15 of some sort and eventually a new VCE later.
 
Huh. Could it have to do with power consumption? Or could it be something akin to three stream engines? What I mean is could there be more than one kind of engine being used? I have a hard time seeing any conventional reason why three engines would be used. It seems to me that an aircraft designed for three engines would be a bad idea in the long term. It is all very strange.
 
Deino said:
Can we can back to reality?? J-36 won't have a ramjet engine anytime and even lesser has now! All three engines are the same and are most likely WS-10C/WS-15 of some sort and eventually a new VCE later.
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Yea I agree which is why I was saying it makes no sense for it to have ramjets or anything
 
TMA1 said:
Might be a silly idea but lets say that you want to test out a mix of different engine types? Maybe you could make a couple test articles that have something like two turbofans and some experimental ramjet or detonation engine?
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Good idea: read some **** airplane design books.
 
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flateric said:
Good idea: read some fcuking airplane design books.
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I am sure someone at Chengdu is reading our posts. I thought of something: maybe the third engine isn’t real, but to fool us…like the XP-59 with the fake propeller.
But seriously, its GOT to be real, probably for a reason that is outrageously simple.
 

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djfawcett said:
If they are really using the 3rd engine for power generation, and I doubt it, there would not be enough thrust coming from the engine to move it on the ramp. Most of the energy will be extracted by the power turbine. The real answer is usually the simplest answer. The engineers did not have an engine that, as a pair, had sufficient thrust to meet the mission. As a result, add number three. Not the ideal answer, but probably the simplest.
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You are aware that you can generate some power from a turbine without specialising the turbine to only produce electrical power?

You do know that a jet aircraft usually have power generators attached to their jet engines? That all jet fighters produce their power this way - and that a third engine would still mean 50% more power if it was being used for thrust like the other two? Also, it might be possible to have one engine optimised to produce a bit more power and a bit less thrust (but still provide a lot of thrust)?

Finally, you are asserting that two WS-10C engines would be unable to move a 45-55ton aircraft on the ramp? You seem to be? You do know that a fully loaded J-16 can weighs 35 tons and a J-20 at full load weighs 37 tons? They seem to move pretty quickly on the tarmac...

You do see you are being very silly right?
 
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sf7pakistan said:
Paper was published September of last year, leads me to think that China was thinking of flying these jets publicly in December 2024 for quite some time. Otherwise the authors might not have been allowed to publish it
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There isn't much original content inside the report. It is even poor in the reported achievements. So, it might even have gone through censorship unnoticed.
The publication date make also think it's not sourced from the original design study but an after party student work. An original paper, dated from the design phase, might be much older than that and include extensive theory or assumptions. Here we've got the results of a FEA presented with a bit of contextual narrative. Great for us here but not much.
 
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flateric said:
Good idea: read some **** airplane design books.
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Is a three engine aircraft with belly and dorsel air intakes normal? Especially in this size? Flateric. You are a boomer hobby forum moderator behaving like an autistic nineteen year old r/LessCredibleDefense moderator. You can say whatever you like to your Internet friends here but please avoid including me from now on.
 
6footboy said:
Excellent. Much better indeed. My question remains. Why would J-36 require a 3rd engine for additional performance (two engine performance seems to be quite good for a 55,000 kg plane)? Why that engine cannot simply be an electrical generator in its primary function? Especially since the 6th generation is so power hungry (radar, processing power, laser-based weapons)?
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Consider the MiG-25, an 80,000lb aircraft, could reach Mach 3 with 2 "22,500lb thrust" engines.
 
Avimimus said:
You are aware that you can generate some power from a turbine without specialising the turbine to only produce electrical power?

You do know that a jet aircraft usually have power generators attached to their jet engines? That all jet fighters produce their power this way - and that a third engine would still mean 50% more power if it was being used for thrust like the other two? Also, it might be possible to have one engine optimised to produce a bit more power and a bit less thrust (but still provide a lot of thrust)?

Finally, you are asserting that two WS-10C engines would be unable to move a 45-55ton aircraft on the ramp? You seem to be? You do know that a fully loaded J-16 can weighs 35 tons and a J-20 at full load weighs 37 tons? They seem to move pretty quickly on the tarmac...

You do see you are being very silly right?
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You should read more carefully. I said the thrust from the exhaust of the center engine, if it were primary power generator, would be insufficient to move the aircraft. What you are saying about the center engine is that they need the additional thrust with the benefit of being able to generate more power by its generator just like the other two.

I realize that you want the J-36 to be something that it is not. It is not a Mach 3 vehicle. Heck, it is not even at Mach 2.5 vehicle. If the air temperature is right (the lower the temperature, the lower the Mach velocity), it might be a Mach 2 flyer, but I doubt it.

I really have no interest in debating this with you. I am pulling from almost 50 yrs experience in this industry, so I am fairly confident that I am close to being right. Why don't we wait for the true specs to come out and then we will see who was the closest. With all of that being said, I really do enjoy reading what you have to say on this forum.
 
djfawcett said:
I really have no interest in debating this with you. I am pulling from almost 50 yrs experience in this industry, so I am fairly confident that I am close to being right. Why don't we wait for the true specs to come out and then we will see who was the closest. With all of that being said, I really do enjoy reading what you have to say on this forum.
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It is worthwhile to point out that many of the people on this forum have expensive experience and are experts in various fields.

But everyone was a beginner once.

Not everyone is ready to bring a beginner up to speed or point them to resources but it is important to remember that long ago many of us sought out information in real, physical libraries and through developing hands on experience and tribal knowledge. Today forums like this serve a similar role for beginners.

…..and wannabe journalists

(Not specific to you @djfawcett but I am seeing some of this across several popular threads with a number of people)
 
One thing that surprise me about about Shenyang aircraft is that Unlike Chengdu one we already have hint of Shenyang aircraft right in front of our face! Various patent, various silhouette in official artwork, etc.

It had always been infront of us!
 

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