Aircraft FS2004 Grob Twin III Acro March 11, 2010 flight2000it FS2004 Grob Twin III Acro (vc), a tandem seater aerobatic glider. Includes front – rear dynamic VC, metric instruments and sounds. FS2K design by Max Roodveldt. Fixed FD for glide ratio and aerobatics by George Csillag. 2,4 Mb