Sideslip (yaw) stability, especially at very high AoA when you have powerful overbody vortices, is what you trade away with all moving tails. The J-20’s all moving tails had to be compensated for with ventral fins. The Su-57 probably deals with this problem through a combination of TVC and differential deflections of its LEVCONS to balance any asymmetrical overbody forces. I strongly suspect the YF-23 dealt with this problem by letting its large engine nacelles act static stabilizers.Yes that's the name. Thanks.
Some one from the other thread thought I was talking about canards. I'm talking about the vertical stabilizers.
Fully rotatable designs instead of rudders are better for stealth. Correct me if I'm wrong but all moving tails (like on the J20 and su57) provides greater control surface, so you don't need to make them as big (such as on the F22 and F35). And I see no evidence that full moving tails are significantly more expensive than rudder design.
It's better to have all moving vertical stabilizers. Thoughts?
Shenyang FC-31 / J-31 Fighter Demonstrator
- Thread starter RedSky
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First question -- what J-20 mockup at Changchun airshow? AFAIK we've never seen an actual J-20 mockup at any airshow. Are you talking about the FC-31 mockup at Changchun airshow instead? Or perhaps I missed something...
As for his claims....
I assume he is suggesting that the first J-XY/J-35 prototype is dubbed 31005.
But this actually raises a bigger question I've been thinking about.
What actually is the PLA designation of J-XY/J-35 going to be?
J-35 to me always seemed like it was a stand-in for the aircraft and was more a reference made by PLA watchers in relation to F-35 than what the serious name of the aircraft would end up being. If the aircraft is actually called J-35 I feel like it would be a bit on the nose.
More importantly, J-35 would be rather uncharacteristic of the PLA to skip its fighter designations from J-20 all the way to J-35. Of course, they have certainly skipped transport and bomber designations to reach Y-20 and H-20 respectively, but I feel like those were more understandable and reasonable because they were obviously seeking to have designation commonality/unity with J-20 and Z-20 etc.
But I can't see a reason why they'd skip all the way to "J-35".
The other possibility is that if the first J-XY prototype is called "31005," then could the actual eventual PLA designation of the aircraft end up being "J-31" instead? That of course would be very ironic as for many years there justifiably have not been any "J-31" but instead FC-31, yet would then be followed by there being a "J-31".
However at the same time going from J-20 to J-31 is quite a large skip as well.
That said, if the actual first J-XY prototype is called "31005" (assuming this guy isn't lying), then that is the only way in which the prototype serial number designation would make sense.
Personally, as far as continuity of designations go, I think that the name for J-XY might most "logically" be called "J-21" as the most likely name, or "J-25" as the second most likely name.
"J-21" because it follows naturally on from J-20. It seems like a no brainer for me, and the PLA has of course been happy to continue from J-10 to J-11 in the past.
"J-25" is a distant second, and would be chosen as J-XY would be a carrier based fighter and be ten ahead of "J-15". But as I said, this one seems less likely to me.
In other words, I wonder if the guy's claims is true or if he's assuming the first J-XY prototype is "31005".
If the actual PLA designation of J-XY is "J-21" instead, I would expect the first prototype to have a s/n of "21001".
Either way, I would just find it really remarkable if the PLA really skip all the way to J-3X designations for the J-XY, as I would have assumed they would be keeping the J-3X designations free for their 6th gen aircraft instead.
I would hazard a guess that the designation of J-XY in the thirties is somewhat geopolitically influenced. USAF jumped to F-22 and then onto to F-35 for their fifth-gen fighters. Sukhoi jumped straight from the thirties to the fifties for their fifth-gen fighter. Placing the J-XY in the 30s provides psychological parity in that a 20-numbered fighter would be perceived as lesser than a 30-numbered one. Before you discount the psychological factor, the appearance of the J-XY would significantly further increase deterrence in Asia-Pacific. You would need to count on every psychological edge you can get. As for the J-20, it was so numbered as part of the '20' family of new modern entrees into the PLA's aircraft inventory and was already set in stone.
It is similar in the civilian aircraft industry, where large jets are numbered in the hundreds because the hundreds provide psychological comfort. Hence C919 and not C9119 or C91. It keeps consumers at psychological ease. There's actually a body of psychology literature to prove that.
Well, that is all assuming the PLA designation of J-XY is in the 30s to begin with.
The idea of the psychological factor might be possible, but overall it seems to me like the "J-35" designation that emerged has largely been accepted as if it is what the actual designation will be without much of a clear reasoning from the community as to the rationale or even the acknowledgement that it is a deviation from past PLA trends.
CAD maestro CaoGeng (AKA grassroot designer) confirms that he was officially invited by AVIC.
In retrospect the workmanship on the Changchun model was rough but the proportions and details were correct. The angle didn't really do it justice either.
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