Its not the Open Alpha folder you rename, its inside of that, try renaming the metashaders folder and leave everything else as is.
@Wolle and BMT I also find that 30+ fps is smooth enough for general flying but any added overheads like MP or lots of units will reduce it further and make it unplayable. Having said that I placed 40 B-17 's in a big formation to carpet bomb an airfield, I also had 12 Spits and 4 Bf109's on the map and it stayed steady @45 fps even when the bombs dropped and that was a lot of bombs!! The same with Nevada now, solid 45 even over vegas at night with high VD. All my flying is with a PD of 1.5:thumbup: