His argument that generations are irrelevant doesn't apply.
Sorry for the initial obtuse wording.
Official Chengdu J-20 Discussion Thread
Sorry for the initial obtuse wording.
I just finished reading "From Rainbow to Gusto" from P. Suhler. Seemed to me to be a good book. Couple of things came across clearly to me, US engineers realized quickly that signal management had to be designed in from the beginning, there was only so much you can do with U2, you have to start from scratch. It takes a lot of effort from different disciplines to make signals management work. It's not just the shape. Also I was never aware until reading this book that US looked at some kind of "plasma" shielding of sorts for inlets and chines of A12/SR71. RCS reduction was really important to CIA and it did come across (to me) that K.Johnson and Lockheed were a bit "slow" in realizing how important this RCS stuff was. They kept pushing different designs without "stealth" and they had to finally do something about it, that jet became A12.
One question I have though is why are the test articles mounted upside down on RCS pylon? I can't find the answer to that one. When they are doing the RCS test in anechoic chamber it seems jets are right side up but when on the outside pylon, why are they upside down? Not just American jets, I have seen pictures of Euro jets and they also mount there test articles upside down?
Might be a few decades before we see a picture of J20 on RCS range.
You can probably appreciate my frustration at arguments proffered that VLO/LO can be retrofitted to earlier generation platforms. All the techno gobbbledygook in the world won't alter the fact that you need to do it properly - and that means at inception. It's not an unknown issue though in the sense that once the refurb market hotted up early this decade, the marketing view of the box floggers (Israeli, France, US, UK) was to try and apply spiral development arguments to those generations. On the surface its a valid argument, at an absolute level, and in the dumbest of analogies, you're still putting low profile sidewalls and a larger turbo on a porsche 924 and saying that its as good as a 928.
What people don't often understand is that the 2 biggest contributers to the evolution of VLO/LO came from the SR-71 (not A-12). One started off on the A-12 but the other was because the mission set resulted in its discovery. It wasn't Lockmart computing that finally made those german and russian computations and theories come to fruition, it was the CIA geek shop. Lockmart just happened to be the easiest vendor to get hold of to do the ground workjust a note, I'm on the Skunkworks distribution group, its comprised of ex Habu and DragonLady drivers as well as ex CIA and USAF staff involved in the progs. Although dwindling, there are still a few of the original Lockmart staff on the group as well. Some of their stories about flying over the USSR are quite "hairy"
I have to say that all the examples I've see on pole tests have been "right way up" - I've never see one on its lid. There are probably obvious engineering issues for this.
Bear in mind that a pole test and an anechoic chamber are designed to do different things. The latter is a captive environment designed to work with proscribed and governable tests, a pole test is an all aspect test done at range and in an open environment. From a signals management perspective, the pole test is what is starting to give "real life" all aspect or significant variance aspect RCS resultspublicly yes. you can't hide a pole test site. even if they pulled down the mounts every night and re-erected it every morning there are other construction "tells" that existMight be a few decades before we see a picture of J20 on RCS range.
You can retrofit, but its a hybrid compromise.
its basic engineering, you cannot, no matter what the marketers say, shift your baseline design into a quantum leap shift.
the basic design is not there. all the marketing spin in the world won't change engineering limitations.
the tactically relevant RCS has to be measured against the likely threat that the buyer is up against.
The SE cements the argument that you get what you pay for. lipstick on a pig is still a pig
Just found this picture of A12 upside down on test pylon, about half way down the article. Looks like the vertical fins have been removed. One can barely make out the cockpit and the exhaust shapes haven't been installed, might still have been early in the program when this picture was taken. Interesting to note from the book that once some of the "stealth" fixtures were installed, the fuel tanks and the engines themselves became important radar surfaces to hide! Just incredible.I have to say that all the examples I've see on pole tests have been "right way up" - I've never see one on its lid. There are probably obvious engineering issues for this.
https://www.cia.gov/library/center-.../from-the-drawing-board-to-factory-floor.html
I apologize that I have gone off topic,my bad. :shudder
Obviously I am no specialist but I think you got the right word :reduction. But no way can you rival a design started from scratch with "stealth" in mind, another good example is Hornet to Super Hornet evolution. SH is a lot better than the Hornet and probably you can still improve some but I guess you reach a "theoretical" limit where that's it, it won't get any better.
The example has to do with the RCS reduction measures, not with the commonality (or lack thereof) between the vanilla Hornet and the Super. The Super had a number of measures put in place to lower RCS that weren't present on the standard Hornet. In that sense it's a good example in that it illustrates the applications and limits of modifying an existing design to incorporate signature reduction.
Apols for off-topic, all.
In other words you can't produce a principal distinction, but you can make quantitative and qualitative improvements. And for large parts of the world, that are far from being able to produce a complete new 5th gen design, these incremental improvements provide an important intermediate step.
I wouldn't be surprised if designs similar to the F-15SE started to spring up elsewhere.
IMO, thats exactly the case
undoubtedly, as it helps in developing and understanding concepts for future implementation
It depends on the market. The Israelis and French do a roaring trade in russian upgrades, but I can't see them doing airframe changes. russian aircraft are already low cost, IMO its not cost effective
the other volume aircraft is the F-16, again, for the same reasons I can't see the market or tactical need.
It would appear that the J20's are about to fly.
Formal delegations in place and 2 aircraft set up for first flight. apparently a third is in place as static..
Formal delegations in place and 2 aircraft set up for first flight. apparently a third is in place as static..
Sampanviking
Banned Member
I think its more interesting to see that a Military Analyst like you and a Geopolitical Analyst like me, can both arrive at the same conclusion by looking at very different data sets.
I agree also that you can overstate matters of difference. Such a difference does indeed exist though and it took me over ten years years to be able appreciate the significance of these differences of the Chinese world view. Without it much will appear strange and disconnected, while with it, the pattern of underlying logic becomes apparent, discernible and even to a degree predictable.
They won't be large airframe changes. The Su-35S features airframe changes and supposedly some RCS reduction. You don't think some of that tech will be included in the MiG-35? Or future Tejas development?
It's premature to pass judgement, but the J-20 may be such a transitional design.
Test flight is delayed. Chengdu has been seeing some foggy weather in the past two days so they may push back the date a week or two.
One thing I do not understand is if they wanted to build an air-superiority LO platform, why the long airframe? For a larger weapon bay? Also, I'd be interested to see how they could mask the canard's signature as well.
I'm not convinced that this is the real deal article for future force construct...
I'm certainly not convinced based on the design as too much of it does not make sense to me. You are not going to have effective LO using canards - irrespective of whats on the net from the "pro-canard club" there is enough evdidence to show why they aren't LO enablers
Handling enablers yes, LO enablers - definitely not. and again, I go back to what I was stating before, is that until we see in flight shots of these aircraft in the turn, then I'm reserving my judgement on it further. eg are they Kfir/Nesher/Lavi/J10 based, Rafale based or Typhoon based - all 3 operate differently.
I'm really of the view that these are first cut CTD's.s
nice effort though, and shows how committed they are.
King Comm
New Member
A long, slender airframe have smaller cross-sectional area. and is easier to conform to the area rule, reducing supersonic drag, the the added lift from a wide, flat fuselage is only beneficial in the subsonic regime.
CAC does have almost 40 years of experience with delta-canard designs, and the world's third largest collection of wind tunnels is in Mianyang, two hours drive from CAC. In addition, Chinese super computers take the 1st and the 3rd place in last year's top 500 list, so one can't seriously think that there would be glaring mistakes or omissions in the design, there can only be trade-offs and compromises based on objectives and constraints. CAC, and PLAAF for that matter, must have deemed that the advantages brought by the canards more than offset the disadvantages caused by increased observability in the missions the plane is expected to perform.
Apart from Nesher, which has no canards, the planes you listed can indeed placed into three groups, however kfir is in a group of its own, since it has non-moving close-coupled canards, Lavi and Rafale both have close-coupled moving canards, and Typhoon and J-10 both have control canards that are further away from the wing.
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the kfir nessher comparison is because one used canards for control, whereas the other went for brute thrust to push aerodynamic control
you've missed the point re Typhoon - its got nothing to do with further placement from the main wings
Typhoon flight management is very very different from Rafale - and its got nothing to do with canard placement, its about how those canards are managed by the FCS.
again, I'm going by the briefings we received from Typhoon pilots, so unless someone has picked it up (and JWCook would know what I'm talking about) then we'll leave it there.
all those planes use different methods of management when employing their canards.
King Comm
New Member
The canards on the Kfir do not serve as control surfaces, they are fixed.
I have not seen the details of the flight control systems used on those planes, so I can only gauge the functions of the canards in terms of aerodynamics, which is dependent on their sizes and placement.
However, I can say that flight control on J-10 is probably very different from Lavi, in fact, you can see with your own eyes:
[ame=http://v.youku.com/v_show/id_XMjI0MDA1NTI4.html]八一æ*¼å战机ç*海航展暴力特技 - 视频 - 优酷视频 - 在线观看[/ame]
Note at 00:48, very prominent differential canard movement, suggesting that J-10 may use its canards for direct sideforce control, something that did not exist in Lavi's time.