Well, this is a very interesting notion with the 30 Hertz / 30 FPS,
thank you Sinky for pointing it out.
I have spent the best part of last week fiddling with that,
and thought, as there is a parameter to be included in the autoexec.cfg:
options.graphics.maxfps = 30
there might be also one:
options.graphics.minfps = 30
This in order to achieve a stable 30 FPS, which guarantees a quite smooth and fluid ride. I spent many hours testing that in all 4 terrains, and it seemed to work, constant 30 FPS everywhere. But all of a sudden for some reason it stopped working.
After a couple of days of further testing, I have come up with the settings depicted in the included screenshot. These settings guarantee 90% of the time (disclaimer, at least with my rig), stable and therefore smooth and fluid 30 FPS in both cockpit and external views, fly-by being a bit stuttery.
Unfortunately, this works only 90% of the time with Caucasus and the Persian Gulf. In Nevada, end even worse in Normandy, the FPS jump from 25 - 30 to 50 - 60 all the time, in both cockpit and external views, causing the dreaded stutters.
Any further ideas?