J-20 5th Generation Fighter VII

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Xizor

Xizor

Captain
Registered Member
Inst said:
Well? So did I hit or miss on the inlet modification speculation?

Unfortunately, researching what happened with the DSI inlets, it seems as though the inlets saw significant modification during the WS-10 / AL-31 stage. This was apparently because of difficulties in optimizing the inlets for the WS-10 / AL-31.

This implies that either two things are possible:

One: the Chinese had tremendous difficulty optimizing both for the stealthiness of the J-20 and the full flight envelope of the J-20. The F-35, in contrast, doesn't need its DSI inlet to exceed Mach 1.6, whereas the J-20 is expected to fly at least to Mach 1.8 and perhaps to Mach 2.4. This implies that without substantial inlet modification (and I'm not saying it'll happen, in fact, I'd find it unlikely), the J-20 cannot extract the full potential of the WS-15.

Two: the J-20 inlets were originally designed for the WS-15, and were then back-engineered to support the Al-31 and WS-10. That's where all the trouble came from; if the WS-15 (and this is likely) required more airflow than the Al-31 and WS-10, the Al-31 and WS-10 would then see excess airflow from a fixed (in the sense that there are no moving parts in the DSI) inlet.

I'd prefer the second scenario to be true, but it's questionable as to how effective reducing the DSI bump might be in fulfilling the WS-15's capability. The bump's job is to get boundary layer air to flow away from the inlet. A large bump implies greater effectiveness in doing so. Shrinking the bump to increase airflow would reduce the effectiveness of the DSI at lower speeds.
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I don't think "reducing" of the DSI bump is actually what is happening. I am expecting the second scenario you laid out to be the reality.

No one can eyeball the DSI and airflows. Complex computing is needed to visualize how DSI affects the flow of air into the inlets. There was a paper ( from NASA / Airforce) that laid out that DSI was effective up until Mach 2. They didn't say that DSI would be ineffective beyond Mach 2 but that it'd require more complex modeling and other mechanism.

I expect J-20 to have some of the most advanced inlet designs ever put on a production fighter jet.

do3jack said:
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The article states that J-20 may move away from Research Institute 14s Radar offering to that of Institute 607. Quick search gives that PL-15 radars were developed by Instit 607.

Apprehensive of the veracity of this.
 
L

latenlazy

Brigadier
sequ said:
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From LKJ86 at PDF
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If this is correct, seems like only one engine is being tested. If that’s the case this is either the final stages of prototype testing or very early into integration testing (not mutually exclusive).
Philister said:
The bump looks different ,image seems legit.
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1625503396183.jpeg
No I think it’s just the angle
siegecrossbow said:
That is way too optimistic. Personally I’d be happy if they mass equip WS-15 by 2030. Turbofans are very hard to master.
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If we consider the WS-10 mastered from the standpoint of production capability then it’s unlikely that a WS-15 that’s made it this far already should see production delays until 2030. You’re not relearning the wheel with every new design.
 
R

Richard Santos

Captain
Registered Member
Inst said:
Disappointing, the WS-15 was apparently being trialed on the J-20 two years back after the new nozzle had been tested on the J-10B platform. If it takes this long to get to a first flight of the WS-15 engine / nozzle, it suggests a great lateness in development processes.
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or excellent security?

The first F-16 to fly experimentally with GE F110 Flew in 1984, while the first production F-16C with F110 flew in 1987. So three years between when an existing fighter first flying with new, more powerful engine and when fighter with new engine entering serial production is not without precedence.

F110 wasn’t even a new engine, the basic engine has been flying since early 1970s. So at least engine performance should be no question mark.
 
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H

henrylowe

Just Hatched
Registered Member
The cartoon guy is about the closest we can get to any definitive proof of any progress in the J-20's development. You may find this unbelievable or even ridiculous, but that's how it is with speculating about Chinese military projects-- rumors from bloggers with consistent credibility always precede the official announcement by anything from a few months to a couple of years, or simply forever, as the case may be. Just live with it.
 
Hendrik_2000

Hendrik_2000

Lieutenant General
henrylowe said:
The cartoon guy is about the closest we can get to any definitive proof of any progress in the J-20's development. You may find this unbelievable or even ridiculous, but that's how it is with speculating about Chinese military projects-- rumors from bloggers with consistent credibility always precede the official announcement by anything from a few months to a couple of years, or simply forever, as the case may be. Just live with it.
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Yup he seem to have good track record. He predicted WS10C on both J10 and J20. Both of them come to be true. Now he come up with this news. So let the time show if he is right
 
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