Chengdu J-20 pictures, analysis and speculation Part II

[overscan (PaulMM)]

Nice pics with J10S.

 

[chuck4]

Why do so many pictures appear to show j-20 with its two all moving vertical tails cocked at wildly different angles?


One would think those tails would either deflect in unison or deflected in mirror symmetry.

 

[famvburg]

They're probably hydraulic and with no pressure they just flop. IIRC, F-18s do the same.

 

[Deino]

Some members of different forums in China are discussing if 2003 has been "rolled-out" .... ???

 

[TAKHISS]

J-20 #2003

 

[Deino]

I agree ... IMO this is for sure a new prototype !
Deino

 

[chuck4]

This one looks like it has a real nose radom. So it probably has a working radar. The bulkhead behind the radar, if delineated by the break in color on the fuselage, seem to lean backwards. That would seem like a characteristic of an AESA radar. Also there seems to be a diamond shaped, upward facing window right ahead of the canopy. Probably some part of a distributed aperture sensor. If it were a simple IRST, it won't face up. I would think this thing is not a prototype but a production-development aircraft.

 

[overscan (PaulMM)]

Played around in GIMP trying to enhance details.

 

[Deino]

Take a look from 1:11 on ...

http://www.56.com/u31/v_NzYwNDkxODA.html#st=86&fromoutpvid=NzYwNDkxODA&

Andi

 

[fightingirish]

With the panels opened, it reminds me very much of that fake CGI from a few years ago.

 

[dark sidius]

The size of this thing is huge

 

[chuck4]

The access panels do not appear to have serrated edges.

 

[flanker]

The access panels do not appear to have serrated edges.

And how many panels did on YF-23 and X-35 for instance? It is prototype, same thing for most part on PAK FA as well.

 

[Deino]

 

[chuck4]

The big hatch right behind the cockpit seems very sturdy and capable of being opened in flight. An hitherto unseen airbreak?

If the arrangement of access panels and avionics bays near the cockpit is similar to production aircraft, then that suggest no space is being reserved for any cheek mounted radar, unless the radar is actually in the bump of the deflectorless inlet.

And yes, the covers for the two access hatches under the forward fuselage has no serration, but the one immediately behind the radar bulkhead does.

Also the avionic service access panels under the chine seems to remove completely instead of hing out of the way. This suggest development aircraft could use some maintenance accessibility enhancements.

 

[Sundog]

The big hatch right behind the cockpit seems very sturdy and capable of being opened in flight. An hitherto unseen airbreak?

It is an air brake and it has been seen in flight on the second prototype.

 

[flateric]

It is an air brake and it has been seen in flight on the second prototype.

...as early as June, 2011

 

[Deino]

Yepp... rarely seen in the open position, but alreay there since the beginning !

 

[Sundog]

Thanks, I never noticed it in my images of the first prototype.

 

[Deino]

I agree ... IMO this is for sure a new prototype !
Deino

Shame on me .... :-\ :-[
It seems as if the conclusion about a third prototype was made a bit too early ! Following these images it is in fact still the second aircraft no. 2002, which was - at least it seems so ??? - "simply" re-equipped with the radar ! (even if image 2 looks strange to me)

Deino

 

[flanker]

"simply" re-equipped with the radar !
Deino

Who says so?

(even if image 2 looks strange to me)

It is obvious PS job with pitot removed and the outline of the new nose shown in a different color.

 

[Deino]

Who says so?

No-one !!! Its an - IMO logical - assumption based on reports, rumours, images of the prototype several days agao with a new radome and work on the avionics and the assumption based on comparisons to ther programs. It surely can be a simply repainted radome to fool us all here but based on what we have it's not too far fetched to assume that the prototype received a radar.
Similar assumptions are done for the T50-3 which is "said" to be equipped with a radar too ... but since the radar itself is not shown I agree with You we have no confirmation on that.

Deino

 

[chuck4]

Why was my observation that j-20's radom appeared to be larger than f22's, signifying a larger aperture AESA, deleted?

 

[Deino]

Actually I don't know ???? ???

Another mystery from today .... IFR-probe or psed again ???

 

[flanker]

No-one !!! Its an - IMO logical - assumption based on reports, rumours, images of the prototype several days agao with a new radome and work on the avionics and the assumption based on comparisons to ther programs. It surely can be a simply repainted radome to fool us all here but based on what we have it's not too far fetched to assume that the prototype received a radar.
Similar assumptions are done for the T50-3 which is "said" to be equipped with a radar too ... but since the radar itself is not shown I agree with You we have no confirmation on that.

Deino

Don't get me wrong, i don't disagree with what you said here. When it comes to T-50-3, i think it having a radar is a bit more trustworthy than 2002 having one. As of now anyway.

IFR pic definitely could be real. There is a panel there. Also, some has said there is new "panels" (with stealthy "teeth") around the nose, imho, they are not new, they are just seen more clearly after the new radome was fitted.

 

[overscan (PaulMM)]

No-one !!! Its an - IMO logical - assumption based on reports, rumours, images of the prototype several days agao with a new radome and work on the avionics and the assumption based on comparisons to ther programs. It surely can be a simply repainted radome to fool us all here but based on what we have it's not too far fetched to assume that the prototype received a radar.
Similar assumptions are done for the T50-3 which is "said" to be equipped with a radar too ... but since the radar itself is not shown I agree with You we have no confirmation on that.

Deino

Don't get me wrong, i don't disagree with what you said here. When it comes to T-50-3, i think it having a radar is a bit more trustworthy than 2002 having one. As of now anyway.

IFR pic definitely could be real. There is a panel there. Also, some has said there is new "panels" (with stealthy "teeth") around the nose, imho, they are not new, they are just seen more clearly after the new radome was fitted.

Could be a new radome plus equipment to test it with. Assuming its a radar is a big leap, especially with the pitot tube still in place - hard to reconcile with an AESA.

 

[chuck4]

Just what kind of radarless radar radome testing requires a lot of equipment that must fly with radarless radome on a plane? It seems to me most testing that can be without the radar are the sort of physical property testing that are better done on the ground. The only major test that might be better done in flight is to check whether it falls off?

Just why is pitot tube on the tip of radome more fundamentally Irreconcilable with AESA?

Pitot tubes are to be seen on the tip of radome of service fighters equipped with PESA, mechanically scanned, or hybrid radar antennas.

Also, why is AESA radar a large leap for j-20? No one made a big fuss when j-10B was seen with a AESA radar, minus the radome.

 

[sferrin]

No one made a big fuss when j-10B was seen with a AESA radar, minus the radome.

It was seen with what looked like an AESA radar. Whether it was a bonified working example is another story entirely.

 

[chuck4]

The Chinese deployed AESA arrays on the type 052C DDG in 2002. They deployed airborne conformal AESA on a IL-76 based AWAC in 2008. They clearly have possessed basic AESA technology long enough for considerable skill maturation. It is reasonable to question the marginal performance and capability of their AESA radars, but it is silly to doubt their capacity to deploy a functioning instrument in a fighter.


The evidence that the radar under j-20's radome is actually AESA is not conclusive based on my knowledge. I noted that the back edge of the radome, where it joins the fuselage, is sloped backwards. This suggested the bulkhead on which the radar is mounted also sloped backwards. This has been indicated by other commentators to be a characteristic trait of AESA. But I wouldn't be able to tell you why AESA tends to be mounted on backward sloping bulkheads, and why other radar antennas tend not tobe.

 

[Deino]

From today ....

 

[overscan (PaulMM)]

Just what kind of radarless radar radome testing requires a lot of equipment that must fly with radarless radome on a plane? It seems to me most testing that can be without the radar are the sort of physical property testing that are better done on the ground. The only major test that might be better done in flight is to check whether it falls off?

Lots of reasons why the radome could change colour and access panels be open. Maybe they just got the grey paint from the supplier and are checking the radar still works OK with it on. Maybe they fitted a new radome for flight testing and are retrieving vibration sensor readings. Who knows?


"Being fitted with new radar" seems unsupported by photographic evidence at this stage. Show me a radar being fitted

Just why is pitot tube on the tip of radome more fundamentally Irreconcilable with AESA?

Pitot tubes are to be seen on the tip of radome of service fighters equipped with PESA, mechanically scanned, or hybrid radar antennas.

Because the nose is a great location for a pitot tube, for most accurate measurement, but the worst place to put it for radar performance. Its a physical obstacle in the way of the radar, causing unwanted reflections and line of sight blockage, reducing stealth. Noone in their right minds designing a stealthy aircraft with high performance radar would put it there except on a prototype where measuring airspeed etc is more relevant than radar performance.

Also, why is AESA radar a large leap for j-20? No one made a big fuss when j-10B was seen with a AESA radar, minus the radome.

I expect J-20 to have AESA. I also expect the nose pitot to be deleted from later J-20s, once radar performance and RCS are being tested.

 

[Deino]

 

[chuck4]

The pre-production F-22s built after 1997 still had prominent air data probes at the tips of their radomes, in conjunction with otherwise production type radomes. When did the first f-22 with operational radar fly?

 

[sferrin]

The Chinese deployed AESA arrays on the type 052C DDG in 2002.

Uhm, no. Those aren't AESAs.

 

[chuck4]

Uhm, yes, they are.

 

[sferrin]

Uhm, yes, they are.

According to Wiki it looks like you might be right. I'd prefer a source a little more reputable myself though.

 

[chuck4]

http://en.wikipedia.org/wiki/Type_052C_destroyer

 

[Avimimus]

By the way - I was curious, given the negative effects of the ventral stakes on low observability - what flight regime is likely to require them?

 

[chuck4]

High AOA. Given the length and configuration of the J-20, and the relatively small size and low height of the rudder/stabilizer, J-20's rudders would probably be ineffective in high AOA and the aircraft would have yaw stability issues without ventral stakes.

I am guessing the roadmap for the J-20's development includes deleting the ventral strake after adding 3-D TV

 

[Sundog]

Any yaw issues they have at high AOA may not require 3D TV to solve. They may be able to do that with the canards alone. But, given that it's still flying with the nose pitot, they may just need them while they calibrate the FCS.