Chengdu J-20 news and analysis Part III

[datafuser]

Is there any official explanation about what these two hexagons are?

 

[totoro]

official? no.

 

[stealthflanker]

Is there any official explanation about what these two hexagons are?

Unlikely unless maybe in several years. The best guess is Chinese version of MADL. On why there are 2 of them it could be because it works on 100% duty cycle means one antenna will always emit while another receive. Both types are phased arrays, with electronic beamsteering.

Another probable reason is that it works on different frequencies. One hexagon with much clearer "grills" works in lower frequency while the other one with much smaller thus appear to be blurred works in higher frequencies.

 

[overscan (PaulMM)]

One alternative theory is that they are boundary air bleed vents or auxillary air intakes related to the intake.

See my posts here : https://www.secretprojects.co.uk/threads/dsi-intakes-ferri-and-chinas-j-20.32468/

 

[pegasus]

nicve thread

 

[datafuser]

Is there any official explanation about what these two hexagons are?

Unlikely unless maybe in several years. The best guess is Chinese version of MADL. On why there are 2 of them it could be because it works on 100% duty cycle means one antenna will always emit while another receive. Both types are phased arrays, with electronic beamsteering.

Another probable reason is that it works on different frequencies. One hexagon with much clearer "grills" works in lower frequency while the other one with much smaller thus appear to be blurred works in higher frequencies.

Too large to be datalink antennas, unless they operate in X-band, perhaps, IMHO. The F-35's MADL operates in K-band and its antenna diameter is about 3 inches.



How about an FMCW side-looking radar? One hexagon to transmit, the other to receive. Or two side-looking radars operating in different frequencies.

 

[overscan (PaulMM)]

Honestly, this doesn't look like an aerial to me. Its a perforated metal plate.

 

[LMFS]

Agree these are vents, the Su-57 has them too:

 

[RanulfC]

Is there any official explanation about what these two hexagons are?

Speaker covers. Can't go into battle without some BA tunes blasting out the soundtrack after all...

Randy

 

[Archibald]

That's one hell of a flying machine. Big, beautiful, brutish... I like it.

 

[Fluff]

Is there any official explanation about what these two hexagons are?

Speaker covers. Can't go into battle without some BA tunes blasting out the soundtrack after all...

Randy

You beat(ha ha ) me to it.

Seriously, if the moon landings can be faked, you need the speakers to make the jet noise, so the GRP lifesize models sound right, and the flying ones are all RC models. That's how Thunderbirds did it.....

 

[Sundog]

Looking at those cockpit photos, the panel layout reminds me of the first generation Gripen.

 

[_Del_]

One alternative theory is that they are boundary air bleed vents or auxillary air intakes related to the intake.

See my posts here : https://www.secretprojects.co.uk/threads/dsi-intakes-ferri-and-chinas-j-20.32468/

Almost certainly this.

 

[overscan (PaulMM)]

Looking at those cockpit photos, the panel layout reminds me of the first generation Gripen.

Actually it seems the pic as posted as early J-20 cockpit is really FC-31. The actual J-20 cockpit seen in the photo has a newer HUD and display technology (either one large panel or two next to each other most likely)

 

[overscan (PaulMM)]

J-20 video and screenshots.

J-20 5th Gen Fighter Thread VI

I think these haven't been posted here yet See this picture here. The J-20 isnt exactly symmetrical. The left side engine intake of the picture is slightly down compare to the right side. and i can just about see the gun opening

www.sinodefenceforum.com

 

[Sundog]

Actually it seems the pic as posted as early J-20 cockpit is really FC-31. The actual J-20 cockpit seen in the photo has a newer HUD and display technology (either one large panel or two next to each other most likely)

Yeah, after re-reading it, I agree.

 

[Forest Green]

[Another probable reason is that it works on different frequencies. One hexagon with much clearer "grills" works in lower frequency while the other one with much smaller thus appear to be blurred works in higher frequencies.

Possibly an interferometry grating for ESM, specifically transmitter geolocation by assessing the phase angle delta between the wave front arriving at the individual holes.

Phase-comparison monopulse - Wikipedia

en.wikipedia.org

https://web.wpi.edu/Pubs/E-project/Available/E-project-101012-211424/unrestricted/DirectionFindingPresentation.pdf

 

[Dreamfighter]

Weird visor/HMDS on that pilot´s helmet, especially when compared with western systems...
The helmet itself looks rather oldfashioned and - with that visor - needing the pilot to do headturns to be able to look somewhat sideways when wanting/needing to rely on his eyeballs as sensors.
Any thoughts, or info?

 

[Forest Green]

Weird visor/HMDS on that pilot´s helmet, especially when compared with western systems...
The helmet itself looks rather oldfashioned and - with that visor - needing the pilot to do headturns to be able to look somewhat sideways when wanting/needing to rely on his eyeballs as sensors.
Any thoughts, or info?

Indeed, poor chap looks like he's going back to the 1970s to watch Jaws 3D at the cinema.

 

[Trident]

While that is clearly a conventional helmet, some other J-20 footage shows the pilot wearing what looks a lot like a HMD. I guess there's little incentive to bring one along to a parade - I wouldn't read much into it.

 

[stealthflanker]

Possibly an interferometry grating for ESM, specifically transmitter geolocation by assessing the phase angle delta between the wave front arriving at the individual holes.

Phase-comparison monopulse - Wikipedia

en.wikipedia.org

https://web.wpi.edu/Pubs/E-project/Available/E-project-101012-211424/unrestricted/DirectionFindingPresentation.pdf

The ESM in other hand may not need grating. It needs radome and may need large spiral antenna or the array thereof . Those in gratings appear to be way too small and way too close to form baseline.

Overscan's assesment regarding the gratings are part of boundary layer removal appears to be very close to truth. As for why it shaped that way it probably for stealth consideration.

 

[Dreamfighter]

While that is clearly a conventional helmet, some other J-20 footage shows the pilot wearing what looks a lot like a HMD. I guess there's little incentive to bring one along to a parade

Sure and I saw the modern one in the vid, but this conventional one just looks weird in those pics.

I wouldn't read much into it.

Just found a different pic of it, posted by Deino on a hobby-forum 1 year ago. There he says it is a new helmet for use on the J-11B, J-15 and SU-35.
Seems nothing special, just looking a bit weird with those 2 holes in the visor-cover.

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www.arcforums.com

 

[sferrin]

 

[Forest Green]

Interesting that you seem to be able to deploy the missiles and close the doors. But I guess that may be more essential for the PLAAF if they haven't got LOAL figured out yet.

 

[totoro]

Closed doors might also be better when maneuvering at supersonic speed, compared to opened doors.

 

[sferrin]

Closed doors might also be better when maneuvering at supersonic speed, compared to opened doors.

Maybe. Didn't stop the F-22 from performing some crazy AIM-9 launches in testing. I'm guessing they're more limited by rail-launch. A missile coming off the rail under a 9G load is going to do weird things.

 

[Trident]

The F-22 was also designed with LOBL, rail-launched missiles in mind, but simply keeps the doors open. I suspect that on the J-20 this isn't an option because it would interfere undesirably with the canards.

 

[overscan (PaulMM)]

Super high resolution shot. The EO sensor seems to be hidden under a cover. The intake grills are very clear and different. Speculation - rear one is an auxilliary intake, front one is boundary layer bleed or bypass duct.

 

[totoro]

They may also just appear different because of the lighting. First one is at a different angle from the second one due to the curve of the intake.

 

[pegasus]

 

[Deino]

Super high resolution shot. The EO sensor seems to be hidden under a cover. The intake grills are very clear and different. Speculation - rear one is an auxilliary intake, front one is boundary layer bleed or bypass duct.

View attachment 620659

Another high resolution image ...

 

[pegasus]

 

[pegasus]

 

[sferrin]

What a beauty. I like it's look better than any other produced 5th gen. It's what I expected the ATF would look like back in the mid 80s.

 

[pegasus]

What a beauty. I like it's look better than any other produced 5th gen. It's what I expected the ATF would look like back in the mid 80s.

If i am honest, in looks I prefer the F-22, i do not like the DSI intakes shape in general, so i do not like the looks of J-31, F-35 nor J-20 in general, i like the F-22 more if am really honest i am more retro, i love the F-14, well what i can expect I was born in 1971 and i fell in love with aviation when i saw pictures of F-14 and MiG-23 and the only few aircrafts i have ever really touched with my hands was an F-14 back in 2002 when the kitty hawk carrier was in Otaru Japan, and they left the public in general to visit the carrier during a friendly visit, it was great to touch F-14, but in reality the F-18 was more beautiful in close up .

I have a collection over 15 F-14 models at home ranging from 1/72 to 1/144, in my heart the Tomcat is my favorite fighter.

 

[overscan (PaulMM)]

Here's a decent behind-the-scenes video of the J-20 parade appearance with English subtitles.

 

[fightingirish]

J-20 test pilot Li Gang was invited to talk on a TV program by China’s CCTV. The episode was aired on Oct. 26.
Besides talking about the maiden flight on the J-20, which was given the callsign 787, Li also spoke on his role in assisting the flight testing of the J-10B TVC aircraft.
Li also talked briefly about the J-20’s anti-electromagnetic interference flight suit.

Video (Chinese):

https://youtu.be/mlExNtPqV-k

 

[pegasus]

 

[pegasus]

 

[Deino]

Even if rumoured since several months and "confirmed" by some grainy images from far away, these are the first clearer images showing the WS-10B (WS-10C ?) powered J-20A allegedly from the second production batch.

Also, Henry K. / EastPendelum mentions, there are some changes visible, that hint to a future TVC engine ... can anyone spot them?

(Images via https://lt.cjdby.net/forum)