Heh, if it isn't the biggest fail himself. First you do not know the requirement or threshold on the RCS return set out by the J-20 program. Second, canards being considered for half a dozen of low observable designs clearly indicate that it is not mutually exclusive, otherwise it would not be considered in the first place.
Heh, if it is not still the fail from your part.
First of all, there is a threshold: The clutter rejection threshold.
Every radar system have it. Either reject it, or your system is overwhelmed with returns. From this perspective, every low radar observable design should have the clutter region as target, else it could not call itself low radar observable. As radar processing technology progresses, the lower the clutter rejection threshold, which will make it increasingly difficult for any design to match its RCS to the newer and lower threshold.
Second,
I never said canards must be excluded. Canards are flight control surfaces that are based on design.
The rules for a low radar observable design are control of:
- Quantity of radiators
- Array of radiators
- Modes of radiation
All low radar observable designs conforms to those rules to varying degrees, so just because newer conceptual designs may have canards, that does not mean current designs conforms to those rules to the same degrees as newer designs. All three rules are equally important and works in concert.
For example...As each flight control surface is a radiator, new conceptual designs may have materials that fully absorb all impinging radar signals, so while the newer design may have more radiators than current designs, the newer materials obeys rule three (modes of radiation) to such a degree that the newer design can be less obedient to rules one and two.
Do you how all of this relate and affects each other ?
I explained all of this a long time ago, as in yrs ago when I first came on this forum. Were you guys asleep in class ?
How come I never hear you pointing out the Pak Fa's airfoil?
It's basically a canard attached a little further back on the fuselage.
Because you were asleep in class ?
The rules for designing a low radar observable body are control of:
- Quantity of radiators
- Array of radiators
- Modes of radiation
So just because one design have more radiators than the next, that does not automatically make it less 'stealthy' than its competitors.
We have one design with a single vertical stab: F-16.
Then we have another design with twin vertical stab: F15.
So under the above three rules, both the F-15 and F-16 are less obedient to rule two: Control of array of radiators.
That is because all the vertical stabs create the dreaded 90 deg corner reflectors.
But if the twin vertical stabs are canted, like the F-18 or F-117 or F-22, the corner reflectors are still there, just not 90 deg. So while the F-18, F-117, and F-22 are less obedient than the F-16 for rule one, the twin canted vertical stabs does not create the dreaded 90 deg corner reflectors like the F-16 does -- all the time. That mean the F-18, F-117, and F-22 are more obedient to rule two than the F-16, hence, despite having more radiators in the tail section, the F-18, F-117, and F-22 are more 'stealthy' than the F-16 in that area.
Do you see how the three rules relate and affects each other ?
For the PAK's large and actuating leading edges, their movements throughout flight and maneuvers falls under rule two: Control of array of radiators.
That is because as they move, they changes their orientation to other structures nearby. The word 'array' mean arrangement and alignment in relation. In a complex body like an aircraft, arrays of radiators are constantly in flux to many degrees. A radiator, like a fin, maybe visible to the seeking radar one second but as the aircraft maneuver, the fin disappeared from radar view, therefore its arrangement to other nearby structures momentarily does not exist -- according to radar view.
I explained all of this yrs ago. What happened ? I cannot dumb it down any further.
