 World Championships are held semiannually throughout the world, most recently in 2008 in France, with a limited slate of events – special varieties of Racing (F2C or "Team Race"), combat (F2D), and speed (F2A), all limited to engines displacing 0.15 cu.in (2.5cc), and Stunt (F2b) which is essentially unlimited with regard to design and size.CIAM (FAI Aeromodelling Commission) designed this classes for F2 Control Line category