F-35 Joint Strike Fighter News, Videos and pics Thread


Anlsvrthng

Senior Member
Registered Member
Yes, the interference between Creeping wave return and Specular return is what caused Mie scattering
General about radar refection: there are 3 main types
Specular returns are the kind of returns where the surface acts like a mirror for the incident radar pulse. Most of the incident radar energy is reflected according to the law of specular reflection ( the angle of reflection is equal to the angle of incidence). This the kind of return that most stealth aircraft reduce by their shaping.
Traveling/Surface wave return: an incident radar wave strike on the aircraft body can generate a traveling current on surface that propagates along a path to surface boundaries such as leading edge, surface discontinuous …etc, such surface boundaries can either cause a backward traveling wave or make the wave scattered in many directions. Stealth aircraft reduce this kind of return by serrated panels and edge treatment



Creeping wave return: this is a form of traveling wave that doesn’t face surface discontinuous and not reflected by obstacle when traveling along object surface so it is able to travel around the object and come back at the radar. Unlike normal traveling wave, creeping wave traveled along surface shadowed from incidence wave (because it has to go around the object). As a result, the amplitude of the creeping wave will reduce the further it has to travel because it can’t feed energy from the incident wave in the shadow region. Creeping wave return are most prominent when wavelength approaches the size of object.
but if you look at my photo earlier you will see the magnitude of creeping wave return is very small compared to specular return, so actually even at low frequency stealth aircraft still very stealthy compared to conventional aircraft.
Or if you don't like theory, you can see the lecture given by Zoltán Dani ( the man who shot down F-117) where he stated the distance which he can detect F-117 even with lowest frequency setting. I posted the video above.
The Mie scattering is a specific solution for the Maxwell equations, NOT a mixture of high school physic explanations.


Zoltán used horizontal polarisation radar, that needs frequency adjustment to match the geometry / orientation of the target.
Vertical polarisation doesn't need that, and has way better detection capability.
S-125 radar :

Nebo-M:

The same reason you can't just destroy targets with Tomahawk. You don't always know the exact target location before hand. You need something with good sensors to come in and find the target for you.
This is a weak try to drop a random support for the F-35 program.

That plane never been designed for that job, if you want to see how a deep penetrator / command centre would looks like check the Su-34.
That has good frontal stealth, big radar, two person crew with comfort utilities ( like place to sleep and so on) ,long range and big weapon load, including capability to carry missiles bigger than the tomahawk.
 

mig-31

New Member
Registered Member
The Mie scattering is a specific solution for the Maxwell equations, NOT a mixture of high school physic explanations.
First of all, those are definitions from "the radar game, understanding stealth and aircraft survivability" by Rebecca Grant, director of Mitchell institute for Airpower studies, they are not high school explanation by any stretch of imagination.Just because Maxwell's equation can be used to calculate the scattered electric field doesn't mean the phenomenon can't be eaplained with words. Mie scattering is a specific phenomenon happens when the wavelength is at least 1/10 time the dimension of target, because when that happen the creeping wave interfered with the specular return => the reflection magnitude fluctuates dramatically depending on the interference is constructive or destructive.










Zoltán used horizontal polarisation radar, that needs frequency adjustment to match the geometry / orientation of the target.
Vertical polarisation doesn't need that, and has way better detection capability.
Horizontal polarized radar basically just means the electromagnetic field is on the horizontal whereas vertical polarized radar basically means the electromagnetic field is vertical. They do not mean suddenly you don't have to satisfy the wavelength-object size requirement for Mie scattering. Vertically polarized radar are less affected by clutter than horizontally polarized one, for low frequency radar using vertical polarized one also mean you got less interference from TV and Radio station which uses horizontal polarization.
Against wing-fuselage blended stealth aircraft, the vertical polarized RCS is higher than the horizontal polarized RCS in most cases, while it is just the opposite for the flying-wing stealth aircraft. For both stealth design, the RCS levels of horizontal and vertical polarized both decrease with the frequency increasing, but the horizontal polarized RCS has a faster downward trend. The surface distribution has little influence on horizontally polarized RCS characteristics. On the contrary, it has a significant impact on Vertical polarized RCS characteristics, and the amplitude of the vertical polarized RCS increases with the surface thickness.





This is a weak try to drop a random support for the F-35 program.
That plane never been designed for that job, if you want to see how a deep penetrator / command centre would looks like check the Su-34.
That has good frontal stealth, big radar, two person crew with comfort utilities ( like place to sleep and so on) ,long range and big weapon load, including capability to carry missiles bigger than the tomahawk.
F-35 is designed for SEAD/DEAD as well as Strategic attack, for SEAD/DEAD you simply can't expect to always know the location of target beforehand.
Su-34 is a strike bomber, very much like F-111. Sure the seat is more comfortable and it can carry heavier load than F-35, but Su-34 isn't stealthy in any shape or form unless we compare it to a B-52. Su-34 has external weapons, a straight inlet with exposed turbine blades, straight up vertical stabilizer making 90 degrees angle with the fuselage, pylons making 90 degrees corner with the wing, rectangle inlet with 90 degrees angle, the 2 inlets also make another right angle corner with the fuselage, even the radar aperture is vertical. In short, Su-34 is as stealthy as a barn
 

Air Force Brat

Brigadier
Super Moderator
First of all, those are definitions from "the radar game, understanding stealth and aircraft survivability" by Rebecca Grant, director of Mitchell institute for Airpower studies, they are not high school explanation by any stretch of imagination.Just because Maxwell's equation can be used to calculate the scattered electric field doesn't mean the phenomenon can't be eaplained with words. Mie scattering is a specific phenomenon happens when the wavelength is at least 1/10 time the dimension of target, because when that happen the creeping wave interfered with the specular return => the reflection magnitude fluctuates dramatically depending on the interference is constructive or destructive.











Horizontal polarized radar basically just means the electromagnetic field is on the horizontal whereas vertical polarized radar basically means the electromagnetic field is vertical. They do not mean suddenly you don't have to satisfy the wavelength-object size requirement for Mie scattering. Vertically polarized radar are less affected by clutter than horizontally polarized one, for low frequency radar using vertical polarized one also mean you got less interference from TV and Radio station which uses horizontal polarization.
Against wing-fuselage blended stealth aircraft, the vertical polarized RCS is higher than the horizontal polarized RCS in most cases, while it is just the opposite for the flying-wing stealth aircraft. For both stealth design, the RCS levels of horizontal and vertical polarized both decrease with the frequency increasing, but the horizontal polarized RCS has a faster downward trend. The surface distribution has little influence on horizontally polarized RCS characteristics. On the contrary, it has a significant impact on Vertical polarized RCS characteristics, and the amplitude of the vertical polarized RCS increases with the surface thickness.






F-35 is designed for SEAD/DEAD as well as Strategic attack, for SEAD/DEAD you simply can't expect to always know the location of target beforehand.
Su-34 is a strike bomber, very much like F-111. Sure the seat is more comfortable and it can carry heavier load than F-35, but Su-34 isn't stealthy in any shape or form unless we compare it to a B-52. Su-34 has external weapons, a straight inlet with exposed turbine blades, straight up vertical stabilizer making 90 degrees angle with the fuselage, pylons making 90 degrees corner with the wing, rectangle inlet with 90 degrees angle, the 2 inlets also make another right angle corner with the fuselage, even the radar aperture is vertical. In short, Su-34 is as stealthy as a barn

Yes, no doubt he can see that, but wishes to "spin a yarn", no doubt the Su-35 will blow up any radar screen in hundreds of miles, LOL... but people got to tell these stories to make the F-35 look bad, or else they got nuthin!
 
F-35 will carry hypersonic missiles
the source appears to be


but I can't find that tweet

OK I won't edit above, but ...
New Lockheed Concept Shows Navy F-35C Armed With Hypersonic Cruise Missiles
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next time you
mig-31
please link a description (money, money, money) or at least a source, not just a picture for fanbois
 
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mankyle

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The dutchs gave a welcome party with Water cannons to their first operational F-35 and the firemen mistakenly used foam instead of Water.
They are checking the plane for possible damage to engine and stealth coating..
 

Anlsvrthng

Senior Member
Registered Member
First of all, those are definitions from "the radar game, understanding stealth and aircraft survivability" by Rebecca Grant, director of Mitchell institute for Airpower studies, they are not high school explanation by any stretch of imagination.Just because Maxwell's equation can be used to calculate the scattered electric field doesn't mean the phenomenon can't be eaplained with words. Mie scattering is a specific phenomenon happens when the wavelength is at least 1/10 time the dimension of target, because when that happen the creeping wave interfered with the specular return => the reflection magnitude fluctuates dramatically depending on the interference is constructive or destructive.
Your description of Mie scatting is the prime example why the non mathematical descriptions has very limited utility.

There is only one field, one result electromagnetic radiation field.

If the elements are simple and easy to calculate (like dipole and few wire) then with trial and error or with these simple rules possible to show results.
These rules are like the basic antenna design stuff, that teached to everyone, or the phased array formulas that makes it simple and possible for a human to understand how its works.

But these rules wasn't enough to decrease the radar returns of the pre-computer age airframes.

Horizontal polarized radar basically just means the electromagnetic field is on the horizontal whereas vertical polarized radar basically means the electromagnetic field is vertical. They do not mean suddenly you don't have to satisfy the wavelength-object size requirement for Mie scattering. Vertically polarized radar are less affected by clutter than horizontally polarized one, for low frequency radar using vertical polarized one also mean you got less interference from TV and Radio station which uses horizontal polarization.
Against wing-fuselage blended stealth aircraft, the vertical polarized RCS is higher than the horizontal polarized RCS in most cases, while it is just the opposite for the flying-wing stealth aircraft. For both stealth design, the RCS levels of horizontal and vertical polarized both decrease with the frequency increasing, but the horizontal polarized RCS has a faster downward trend. The surface distribution has little influence on horizontally polarized RCS characteristics. On the contrary, it has a significant impact on Vertical polarized RCS characteristics, and the amplitude of the vertical polarized RCS increases with the surface thickness.
If you dig deeper into the frequency-stealth problem then you will find interesting RCS diagrams from stealth aircrafts with different polarisation.

I linked a few into this forum in the past as well.

However best part of them is Russian/Hungarian/Serb.

The high lenght:width ratio has to be perpendicular to the polarisation direction to have non-frequency depended return from the target.


Sure the seat is more comfortable and it can carry heavier load than F-35, but Su-34 isn't stealthy in any shape or form unless we compare it to a B-52. Su-34 has external weapons, a straight inlet with exposed turbine blades, straight up vertical stabilizer making 90 degrees angle with the fuselage, pylons making 90 degrees corner with the wing, rectangle inlet with 90 degrees angle, the 2 inlets also make another right angle corner with the fuselage, even the radar aperture is vertical. In short, Su-34 is as stealthy as a barn
Take more careful look of the Su-34 frontal shape.

You will be surprised.
 

mig-31

New Member
Registered Member
Your description of Mie scatting is the prime example why the non mathematical descriptions has very limited utility.
There is only one field, one result electromagnetic radiation field.
If the elements are simple and easy to calculate (like dipole and few wire) then with trial and error or with these simple rules possible to show results.
These rules are like the basic antenna design stuff, that teached to everyone, or the phased array formulas that makes it simple and possible for a human to understand how its works.
But these rules wasn't enough to decrease the radar returns of the pre-computer age airframes.
You are confusing between a definition and description of a phenomenon and the formula/equation used to calculate the effect of such a phenomenon.
What I gave is a description of return in Mie region. To calculate the effect then you have to use equation and formula. To apply in the real world you normally need a computer to do the calculation for you.
For example: If the task is to make a plane fly.
The description would be: to generate more lift than the mass of the airplane.
The equation would be: Lift = 1/2*air density*lift coefficient* velocity^2* reference wing area.
The practical design would be: using wind tunnel to measure lift coefficient of different shape and their structural strength.
Similarly, the description I cited are the general guidance to how you should design a stealth aircraft: avoid corner, avoid sharp edges, avoid gaps ..etc. But to know what is the most optimum way to do them, you need a computer, because even though you have the equation and you have the theory, doing the thounsands-millions calculation is not the task that anyone really wants to do.



If you dig deeper into the frequency-stealth problem then you will find interesting RCS diagrams from stealth aircrafts with different polarisation.
I linked a few into this forum in the past as well.
However best part of them is Russian/Hungarian/Serb.
The high lenght:width ratio has to be perpendicular to the polarisation direction to have non-frequency depended return from the target.
Of course I know aircraft have different radar scattering characteristic in vertical and horizontal polarization, the graph I posted in the previous post literally shown that.
Besides, you are mistaken, only return in optical region (high frequency radar) can be independent of the frequency, whereas return in Mie and Rayleigh region (low frequency radar) is always dependent on frequency.


Take more careful look of the Su-34 frontal shape.
You will be surprised.
Yes the nose of Su-34 is not a cylinder, so that help prevent creeping wave return, however, apart from that tiny detail, Su-34 does nothing to reduce specular and creeping wave return, like I said before: has external weapons (keep in mind most missiles and bombs has cylinder shape), a straight inlet with exposed turbine blades, straight up vertical stabilizer making 90 degrees angle with the fuselage, pylons making 90 degrees corner with the wing, rectangle inlet with 90 degrees angle, the 2 inlets also make another right angle corner with the fuselage, the radar aperture is vertical, the trailing and leading edges have no edge treatment. In other words, the nose of su-34 is the equivalent of putting lipstick on a pig or putting V-tail on B-52. It won't make su-34 stealthy in any shape or form.
 

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