Do individual weapons/stores add to the overall RCS in DCS

So how long did that take to run? and I assume you ran the vertical slices too? Could you post a 3d blob graph?

The run time wasn't as bad as I expected compared to my previous experiments with RCS. I can't remember exactly, but i think it was around 30 minutes, with a coarse mesh, 2° steps in φ, using the physical optics solver (with a different computer than the workstation described earlier). I haven't done any other simulation than the one in the horizontal plane yet, but it is on my to-do-list.

I'd mainly be curious in runtimes on aircraft. I.e. how long would it take to run this on an aircraft X however many are in DCS (100?), and come up with some reasonably resolved angle/RCS look up table.

You don't need a lot of angles on an aircraft because RCS follows some simple rules of thumb. The biggest issue (IMHO) is getting the model correct in all respects, which you will probably not be able to do, thus ending up with incorrect RCS' ... in some cases very incorrect.

I was certainly surprised to see MiG-21's measured at 10m^2 RCS.

I made a few changes to my HARM model. There aren't many (or any) good sources of info on what the antenna under the radome acturlly looks like, but there is a low detail drawing from Raytheon floating around that shows a configuration with a conical log spiral antenna (which seems plausible, given the ultra wideband nature of the 88's seeker). I simplified it (a lot) by just modelling the whole seeker electronics and antenna section as a simple extruded cylinder.

I excluded the radome from the simulation (messing around with dielectric media increases the processing time too much), and the result was, as expected, quite different from the previous "metallic radome" test:

I have also played around a bit with one of the example models included with the training material; a Denel Rooivalk!

The plan was to get a simple 3d rcs pattern of the right hemisphere (at 1° steps), but I had to cut the simulation short after 3,5 hours (85%), so the frontal aspect of the "blob" is missing. The material is a perfect electric conductor, and the frequency is 1GHz (linearly polarized).

RCS varies with material, frequency, polarization and aspect ratio, so none of these walues can be claimed to be correct, as there are too many variables to take into account.