archangel117 wrote:In the world of stealth even the smallest features can radically change the RCS of an object, yes even a Milimeter
Very doubtful statement. According to conventional physics 1 mm should not have a significant influence on 30-mm wave.
Where is that world of stealth - in alternative universe?
First of all - not -18 but -9 dBsm:
![rcs2.png](./download/file.php?id=19764&sid=5c762575cf38d4b153c1ff2c6828ca9e)
- rcs2.png (36.89 KiB) Viewed 114593 times
archangel117 wrote:This is without R.A.M or R.A.S and is admitted by them to be a imperfect model of the craft. Yet if we apply the values for the R.A.M depicted in figure 7 here:
http://www.freepatentsonline.com/5164242.pdf it can easily be seen how the RCS in the X-band can be -40 dBsm In the frontal aspect.
I dont know the CST program, but ADS by Agilent and Microwave office by AWR are similar to it (designed for the same tasks). I simulated just a small phased array antenna (near 30 elements) and the process took a significant part of my 64 GB RAM (compare to 500 MB in the article) and lasted also several hours. And very doubtful that they have a 3D model of Raptor with 1-mm precision. But the improvement in model precision may lead to a better or a worse result with an equal probability.
Go ahead. Take this picture:
![rcs.png](./download/file.php?id=19765&sid=5c762575cf38d4b153c1ff2c6828ca9e)
- rcs.png (49.53 KiB) Viewed 114593 times
and this:
![ram.png](./download/file.php?id=19766&sid=5c762575cf38d4b153c1ff2c6828ca9e)
- ram.png (60.59 KiB) Viewed 114593 times
You see that we can get a value near -13 dBsm (0.05 sq.m.) at 10 GHz.
And what I calculated earlier - a piece of canopy, it is not covered with RAM so the laue I got - 0.00058 - is still a part of overall RCS, even if the RAM attenuation will be applied to a model.
I want to say again. I DO NOT reject the value of -40 dBsm at all.
I believe that it is true, but with some more specification of its applicability. I've told about its narrow angle localization, and here is frequency dependence too.
So this is not a figure we can rely on upon estimating tracking range etc.
What about USAF officials - they wanted to compliment themselves.
And they wanted to get more money for further Raptor production.
Just businness, nothing wrong with it.