Chengdu next gen combat aircraft (?J-36) thread

[marcello]

PSed. The author just copied-&-pasted that sole accompanying J-20S.

oke thanks for the information

 

[tphuang]

There was a pretty old interview of Chengdu's Yang Wei:

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He mentioned some core components will be used for the first time in the next gen fighter:

• Terahertz (THz) radar
• AI system
• Adaptive Variable Cycle Engine
• Wing changing shapes (I guess this means flexible wing material)

Anyone has more details? I don't expect China's ACE engine to be ready yet, for example.

Is the THz radar actually feasible? Or, that was what's inside the large window on the chin? My understanding is THz is basically IR, which does not have a very long range.

Okay so I looked up Guobo development a while back and they were at around 100Ghz a year ago. Likely using GaN on silicon wafers.

however, that’s where GaO on diamond comes into play. Extremely wide band gap and electrical conductivity with GaO. When placed on diamond wafer, thermal conductivity is really high too.

that allows it to operate at much higher voltage and frequency.

Still, it’s unlikely higher frequencies radar in that range is actually developed for fighter jet. I would need to do some reading on this.

 

[latenlazy]

Interesting sketch by Cute Orca's friend. Would be amazing if the J-36 can indeed fit two smaller-sized HGV missiles inside its main IWB.

https://twitter.com/i/web/status/1874611742812299564

View attachment 142431

Why do a boosted HGV when you can do an air breathing hypersonic cruise missile using the aircraft’s top speed as an ignition boost…

 

[Neurosmith]

Why do a boosted HGV when you can do an air breathing hypersonic cruise missile using the aircraft’s top speed as an ignition boost…

HGVs and most ballistic missiles have a much higher terminal speed - and sometimes more unpredictable trajectory in the case of HGVs - than air-breathing cruise missiles. This is likely one of the reasons why the DF-100 program was concluded early in favor of the DF-21D/26.

 

[latenlazy]

I am Ok with the first part, but I am still having some trouble understanding the second part. It seems to me that the molar heat capacity of fuel is tiny compared to the molar enthalpy of combustion.

let's look at decane, assumed as the average alkane in fuel:

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molar heat capacity: C = 0.315 kJ/(K*mol)
molar specific enthalpy of combustion: Hc = 6777 kJ/mol

So even if the fuel was preheated by +100C such that C*T= 31.5 kJ/mol, the extra thermal energy of the fuel is almost negligible at 0.5% of combustion enthalpy.

And since the fuel has to be cooled below a flashpoint at ~150C, it can't handle all that much heat, since the combustion is producing ~200x more heat than the fuel is absorbing. Overall, dumping heat into the fuel is a net negative, and active cooling is still required. And active cooling for a supersonic plane is difficult due to higher air temperatures and lack of conductive cooling.

As I said earlier all the heat your engine is generating is being dumped via propulsion. You are heating the fuel with the things you’re trying to cool and then dumping the heat into the engine which is expelling the heat. All the internal heat from the aircraft starts from the engine anyways, since that’s what’s powering all the systems. Heating the fuel isn’t “adding” heat but recycling it back to the engine. You’re moving heat from the places you don’t want it to be to the places you’re okay with.

 

[latenlazy]

HGVs and most ballistic missiles have a much higher terminal speed - and sometimes more unpredictable trajectory in the case of HGVs - than air-breathing cruise missiles. This is likely one of the reasons why the DF-100 program was concluded early in favor of the DF-21D/26.

The DF-100 was concluded because it could only reach Mach 4 and probably approaches at very high altitude, so didn’t offer much in terms of detection window advantage. An ideal air launched HCM should probably be at least Mach 5, and since it’s powered it will probably more maneuverable and can fly more varied evasion patterns than an HGV.

 

[sunnymaxi]

As in built a full scale prototype? That would be big news for development. Going to 3-stream would be a radical upgrade. US spent almost 20 years maturing 3 stream tech after figuring out 2 stream design. From what I remember the YF-120 had higher supersonic performance benefits over the F-119 thanks to its VCE design but was very thirsty. 3 stream design like XA100 has even better performance but its also more fuel efficient.

in December 2022, during conference

''all related Technologies and Material successfully developed for next generation Engine'' confirmed by Liu Daxiang, member of Chinese academy of Engineering and father of China's turbofan Engine industry.

most probably, WS-XX entered in full scale prototype stage now.. so this is indeed a big news but the most important point. what final specific design and configuration they go with. there has been quite significant research in last few years related 'Cycle propulsion'. so it is most likely in the line of XA100/101.. let see

 

[latenlazy]

in December 2022, during conference

''all related Technologies and Material successfully developed for next generation Engine'' confirmed by Liu Daxiang, member of Chinese academy of Engineering and father of China's turbofan Engine industry.

most probably, WS-XX entered in full scale prototype stage now.. so this is indeed a big news but the most important point. what final specific design and configuration they go with. there has been quite significant research in last few years related ''Three spool'' turbofan. so it is most likely in the line of XA100/101.. let see

Eh I think the 3 spool turbofan is related to a different (likely commercial) project…

 

[siegecrossbow]

Going old school with the promotional art.

 

[ACuriousPLAFan]

Some artistic illustrations on exploring how the J-36 may be armed in the future, with the possibility of dual-stacking the AAMs inside the J-36's main IWB. Posted by @Hurin92 on Twitter.

If this arrangement is possible, then a max loadout of 8x PL-17s and 6x PL-15s should be viable (or perhaps swapping the PL-15s with 12x tandemly-arranged micro-AAMs for self-defense).