structs, pointer, static callback function

[jacek]

error C2440: '=' : cannot convert from 'void (_thiscall Model::*)(void)' to 'void (_cdecl *)(void)'

That flyStop field was declared as a pointer to a function that has no parameter and doesn't return anything. You can't make it point to a method of Model class, unless you change its type to void (Model::*flyStop)(void).