PRC VCE and low bypass engines (fighters, tactical jets, UAVs, others)

00CuriousObserver · Mar 14, 2026

Moderator edit:
Old thread here:

Chinese Engine Development

I'm going to create two new threads separate from this one, to continue our future engine discussions, and will lock this for now.

www.sinodefenceforum.com

Thread for high bypass engines, turboprops, tubroshafts here:

PRC high bypass engine, turboprop, turboshaft, and other aeroengines

Old thread here: https://www.sinodefenceforum.com/t/chinese-engine-development.252/page-1016#post-1306607 Thread for VCEs and low bypass engines and engines for tactical aircraft in this thread...

www.sinodefenceforum.com

==

Hehe

~~(I remember there was a VCE thread but I can't seem to find it)~~ or maybe not

This application belongs to the technical field of aircraft engine design, and specifically relates to a three-duct variable-cycle aircraft engine.

A third duct is added between the inner duct and the outer duct, and a diversion fan is added behind the main fan. The diversion fan further includes:

a first-stage diversion fan

a second-stage diversion fan

The first-stage diversion fan is located inside the inlet of the third duct, in front of the inner duct.

The second-stage diversion fan is located inside the inlet of the inner duct.

The first-stage and second-stage diversion fans are connected by a drum/casing.

The second-stage diversion fan is connected to the front end of the low-pressure shaft through a diversion-fan shaft.

A variable-speed gearbox is connected inside the front end of the low-pressure shaft, and the output shaft of the variable-speed gearbox is connected to the fan through a fan shaft.

CN116163854A, “Method for Controlling Mode Switching of a Dual-Bypass Compressor in a Variable-Cycle Aircraft Engine”

Publication date: 2023-05-26

Application date: 2023-02-20

Category:
Combustion engines, engine installations using hot gas or combustion products

Invention title:
Method for Controlling Mode Switching of a Dual-Bypass Compressor in a Variable-Cycle Aircraft Engine

Blitzo · Mar 14, 2026

Old thread here:

Chinese Engine Development

I'm going to create two new threads separate from this one, to continue our future engine discussions, and will lock this for now.

www.sinodefenceforum.com

Thread for high bypass engines, turboprops, tubroshafts here:

PRC high bypass engine, turboprop, turboshaft, and other aeroengines

Old thread here: https://www.sinodefenceforum.com/t/chinese-engine-development.252/page-1016#post-1306607 Thread for VCEs and low bypass engines and engines for tactical aircraft in this thread...

www.sinodefenceforum.com

The reason for this delineation in engine topics is because a bulk of the previous engine thread's discussions revolved around low bypass engines/engines for fighter aircraft, which understandably is a major focus and source of major interest.

This thread will be primarily for those types of engines, a list of examples but not exhaustive including:
- WS-10, WS-15, WS-13, WS-21, WS-19, WS-9, etc...
- VCE/ACE efforts for future fighters
- Engines for various trainers
- Likely engines for H-20 and GJ-X and WZ-X etc

If you're wondering if an engine is "high bypass" or "low bypass," I advise to just use some common sense. If something looks like it'll fit on a modern airliner, then it's probably high bypass.

daddycals · Mar 15, 2026

A patent for a vce nozzle

Alfa_Particle · Mar 15, 2026

00CuriousObserver said:
Moderator edit:
Old thread here:

Chinese Engine Development

I'm going to create two new threads separate from this one, to continue our future engine discussions, and will lock this for now.

www.sinodefenceforum.com

Thread for high bypass engines, turboprops, tubroshafts here:

PRC high bypass engine, turboprop, turboshaft, and other aeroengines

Old thread here: https://www.sinodefenceforum.com/t/chinese-engine-development.252/page-1016#post-1306607 Thread for VCEs and low bypass engines and engines for tactical aircraft in this thread...

www.sinodefenceforum.com

==

Hehe

~~(I remember there was a VCE thread but I can't seem to find it)~~ or maybe not

They're putting GTF tech in ACEs? Fun.

sunnymaxi · Mar 15, 2026

Alfa_Particle said:
They're putting GTF tech in ACEs? Fun.

Three shaft ACE+GTE configuration. such a complex machine

looks like they focused on fuel efficiency and durability.

Alfa_Particle · Mar 15, 2026

00CuriousObserver said:
Moderator edit:
Old thread here:

Chinese Engine Development

I'm going to create two new threads separate from this one, to continue our future engine discussions, and will lock this for now.

www.sinodefenceforum.com

Thread for high bypass engines, turboprops, tubroshafts here:

PRC high bypass engine, turboprop, turboshaft, and other aeroengines

Old thread here: https://www.sinodefenceforum.com/t/chinese-engine-development.252/page-1016#post-1306607 Thread for VCEs and low bypass engines and engines for tactical aircraft in this thread...

www.sinodefenceforum.com

==

Hehe

~~(I remember there was a VCE thread but I can't seem to find it)~~ or maybe not

And here I was wondering what 606 projects that would ever need a GTF mechanism (great dig by @sunnymaxi), guess we found the culprit:

siegecrossbow · Mar 15, 2026

daddycals said:
View attachment 171624A patent for a vce nozzle

So there is an S curve in the rear aspect as well. Probably don’t need engine blocker for such a design. Imagine the sheer performance to allow for such extravagance.

ACuriousPLAFan · Mar 15, 2026

00CuriousObserver said:
Moderator edit:
Old thread here:

Chinese Engine Development

I'm going to create two new threads separate from this one, to continue our future engine discussions, and will lock this for now.

www.sinodefenceforum.com

Thread for high bypass engines, turboprops, tubroshafts here:

PRC high bypass engine, turboprop, turboshaft, and other aeroengines

Old thread here: https://www.sinodefenceforum.com/t/chinese-engine-development.252/page-1016#post-1306607 Thread for VCEs and low bypass engines and engines for tactical aircraft in this thread...

www.sinodefenceforum.com

==

Hehe

~~(I remember there was a VCE thread but I can't seem to find it)~~ or maybe not

Another one, likely from the same patent document(s).

Alfa_Particle · Mar 15, 2026

ACuriousPLAFan said:
Another one, likely from the same patent document(s).

View attachment 171645

This is what I originally envisioned their ACE would be, yeah:

Screenshot_20260315_211916_org_mozilla_firefox_HomeActivity.jpg

With the GTF one they're taking a special approach of having a geared fan then two diverting fans, one nested in the HPC duct and the other where the CDFS would usually be. I guess we'll see eventually what kinda novel architecture they'll settle on.

Edit: hold on I completed skimmed over an extremely important detail. The CDFS here has adjustable blades?? Whoa. That's also quite neat.

Edit #2: this design with the VCDFS has one of the patentnees listed as 刘永泉... Something to note.

Alfa_Particle · Mar 15, 2026

While we've talked about this before, I don't believe anyone has posted this yet. Here's a radar + IR blocker integrated afterburner, one of the patentnees being the very chief engineer of the WS-15, dating back to 2021. I think this should give a very solid (but of course, not concrete) answer to the "does the WS-15 actually have a radar blocker?" question (I personally find it silly that this is even a question in the first place):