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

[GTI]

whatis NGAP

NGAP = Next-Generation Adaptive Propulsion (NGAD’s engine)

NGAS = Next-Generation Aerial Refueling System (new tanker)

NGAD = Next-Generation Air Dominance.

NGAD is technically a family of systems that comprises PCA, PLRS, P-AEA, P-ISR and slightly separately, LRS-B.*

*Penetrating Counter Air (PCA), Penetrating Long Range Strike (P-LRS), Penetrating Stand-in Airborne Electronic Attack (P-AEA), Penetrating Intelligence, Surveillance and Reconnaissance (P-ISR), Long Range Strike Bomber (LRS-B)… noting there are some text-wall loving members who do not believe next gens like J-36 would be doing stand-in EW and ISR.

 

[Alfa_Particle]

Do we know what kind of VCE they are working on? the VCE of the YF-120 kind is very very different to the much more complex 3 stream design for XA100 and NGAP. NGAP will be even more advanced than that bringing variable tech to the turbine core. I hope its the latter, if so that will be the most monumental tech leap China will ever make wow..

ACE, basically Chinese AETP (XA100/101).

They experimented with a two-stream VCE quite some time ago already.

 

[Blitzo]

There's been a lot of VCE/ACE papers over the years from relevant Chinese institutes.

I collected quite a few a year or so ago, but there's so many that it's basically drinking from a garden hose. Better just to wait and see what the final specific design and configuration they go with imo

 

[sevrent]

ACE, basically Chinese AETP (XA100/101).

They experimented with a two-stream VCE quite some time ago already.

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.

 

[ZeEa5KPul]

I collected quite a few a year or so ago, but there's so many that it's basically drinking from a garden hose.

I want to point out that this is not a problem we've historically had in this game.

 

[FairAndUnbiased]

the PV diagram refers to the working fluid, which is air. the inlet air temperature stays the same, but the outlet air temperature will be higher if the fuel is preheated since more of the thermal energy from combustion will go towards heating the air vs warming up the fuel to combustion temperature

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.

 

[Blitzo]

I want to point out that this is not a problem we've historically had in this game.

I have a feeling that the relative novelty of VCEs/ACEs around the world means that the threshold of basic developmental and pre-research work is somewhat lower in classification or sensitivity.

Whether any of the papers are related to the actual VCE they are developing for J-36 otoh, who knows

 

[marcello]

is this real

 

[iewgnem]

I have been rereading articles surrounding the 2020 USAF NGAD prototype/demonstrator reveal. It turns out the same USAF official who claimed that an NGAD prototype/demonstrator flew in 2020 was the guy who championed the now canceled “digital century series.”

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In fact, with the information we now have about the NGAD program delays and rework, it seem very likely that the 2020 prototype was a one-off commission to quickly build something that looks good and flys to validate the “digital design process” concept that the USAF want to sell to Congress.

Some examples of the USAF digital design initative includes

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In fact, I suspect the technology that the 2020 demonstrator was demonstrating was “digital engineering/rapid prototyping” instead of any groundbreaking aerodynamics/signature reduction/sensors/power management etc. that we associate with 6th gen. It would explain why LM and Boeing were still in the design phase and why the project could be fundamentally reworked.

If this is the case, it would mean China is even more ahead with the J-36 and SHENGAD.

I maintain the NGAD prototype they flew was something like Model 437

 

[ACuriousPLAFan]

View attachment 142449is this real

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