If you want a 50cc plane for 3D do not get the Patty or the GP Sukhoi.Too small and heavy.I know they are cheaper than some others,but you are cheating yourself.
Get a Wildhare Extra or Extreme Flight Extra or Aeroworks.They also offer Edges and Sukhois and Yaks
nearly every plane will have coupling,and since nearly no manufaturer builds exact scale aerobatic planes,one cannot state that a Sukhoi will not pull in KE and this and that.It really is the design.Some companies built a look alike Yak,but really it ends up being some sort of freakish looking thing with entirely different outlines and handling character than the next company.