No can do. That is not how it works. The canards themselves, as physical beings, do contribute to the final RCS. But also relevant is how the radar signals that came off them and impact other structures, will affect those other structures as contributors. This is why it is quite difficult to understand how RCS is calculated. People think that we measure one structure at a time, add them all up and call it good. That is NOT how it works. In a complex body, a structure is a contributor in two ways: by itself, and by the subsequent effects of the radar signals that came off it that may or may not impact other structures. Most people tends to focus only on the former.
J-20... The New Generation Fighter II
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If there was a like function in this forum I would like this.
Yes it would. But look at it this way...
The canard would have to absorb literally %100 of the impinging radar signal. Even so...It is that 'knife edge' scattering point effect that increases unpredictability. You cannot view the radar signal as that like a laser beam. You must view it like a cone and part of that cone will be interrupted by that 'knife edge' to create unpredictable behavior of the radar signal.
Kk, thanks for the intruiging posts anyway even though I don't think you really understood what I was asking. ^^
I think he was saying that the using diagonal edge alignment increases the variability of reflection. Think of it this way. If the trailing edge of the Canard is aligned with the diagonal wing's trailing edge the waves that clear the body of the plane will be fine and redirected one way, but the ones that don't will be subjected to further reflection off the surface of the plane and will be much harder to control. Whether this will generate a higher return or not will depend on the position of the beam to the body of the plane as well as how the body of the plane will deal with these reflected waves.
Yes it would. But look at it this way...
The canard would have to absorb literally %100 of the impinging radar signal. Even so...It is that 'knife edge' scattering point effect that increases unpredictability. You cannot view the radar signal as that like a laser beam. You must view it like a cone and part of that cone will be interrupted by that 'knife edge' to create unpredictable behavior of the radar signal.
One more question for gambit. Would using RAM on the edges help reduce or eliminate the knife edge effect? Also, radar absorbent materials block radar waves to an extent, but how much EM interaction would radar transparent materials experience? What effect would this have on radar reflection?
I do understand.
Let me put it this way...If we take the 'red' canards and measure them against the 'blue' canards WITHOUT the aircraft involved, most likely we would get the same measurements for both pairs because each of them would radiate into free space after giving the radar some reflected signals.
But if we introduce the aircraft, as the 'red' canard have a different trailing edge angle than the 'blue' canard, now due to the 'knife edge' scattering point effect we have to find out...
- Which direction they will radiate
- If the radiated signals imping upon another structure, the different angle of approach will produce different of deflections off that structure.
Different angles, approach or reflected, will produce different results by the same structure.
Some...But the issue now is absorption rate by the material...
We are not talking cell phones here but with greater microwave power and higher freqs. Absorber design and construction have a direct effect on absorption rate. Ideally, we want instantaneous absorption but the reality is that absorption is essentially a mechanical process. We are not countering a signal with another but opposite signal. We are making the signal travel in the strata of the absorber until its energy is spent or converted into heat. Some of the impinging radar signal will become surface wave and will be scattered by that 'knife edge' effect.
Radome material is what you are talking about. Radome material is absorber or 'pass through' material. It first absorb but instead of trying to trap the signal and convert it to heat the absorber allow the radar signal to pass through so the pilot can see ahead of him. If the canards are made of 'pass through' material, then it would be as if they are not there. But 'pass through' material are usually, and currently must be, freq selective, meaning they must be 'tuned' for a specific freq, which for the radome is the operating freq of the aircraft's radar.
Let's say the radar signal is impinging onto the airframe in the frontal directions. Creeping waves along the surface of the canards would be attenuated by RAM coating, such that the remaining radar signal to be scattered at the trailing edges, while part of it, re-impinged onto the fuselage and the main wings, would become secondary effects as compared to the direct radar signal impinging onto the fuselage and the main wings. Together with the smaller dimensions of the canards, a simplified answer would be, the canards would only have secondary contributions on the overall RCS, including considerations of whether the trailing edges, align with the rest of the airframe.
Martian
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China J-20 Mighty Dragon leaves an impressive plume
China J-20 Mighty Dragon releases a fiery breath.
"The condensation trail left behind jet aircrafts are called contrails. Contrails form when hot humid air from jet exhaust mixes with environmental air of low vapor pressure and low temperature. The mixing is a result of turbulence generated by the engine exhaust. Cloud formation by a mixing process is similar to the cloud you see when you exhale and 'see your breath.'"
[Note: Thank you to "A.Man" for the picture.]
China J-20 Mighty Dragon releases a fiery breath.
"The condensation trail left behind jet aircrafts are called contrails. Contrails form when hot humid air from jet exhaust mixes with environmental air of low vapor pressure and low temperature. The mixing is a result of turbulence generated by the engine exhaust. Cloud formation by a mixing process is similar to the cloud you see when you exhale and 'see your breath.'"
[Note: Thank you to "A.Man" for the picture.]
I don't think they're contrails, I heard someone on another forum saying the J-20 was dumping fuel.
I see... so we can not definitively say which trailing edge configuration would produce a lower return, right?
I see... so we can not definitively say which trailing edge configuration would produce a lower return, right?
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