Hi Marcos:
Yes, the Funtana 90 pulls hard to the right when you pull hard up.
Personally, I feel it is because of the P factor and if you sit the airplane on a bench and run the engine up, you will notice that the prop blast will press on the right side of the rudder and vertical fin. Now put your hand on the left side and you will notice almost no airflow compared to the right side. This is the twisting action from the propellor and the air comes off the left side of the prop, down and under and around to the right side.
Apparently the designer had this problem as well and that is why they intalled those wedge shaped sections to the back of the wing at the root. We've tried everything and so far, have found no cure. I've tested three Funtana 90's and they all do the same thing.
We even tried a balsa ventral fin in front of the vertical stab and it just made it worse.
Let us know if you come up with a solution.

3dbob