Its amazing, this issue has been dealt with in detail by me and othe rposters in the Funtana 90! thread and others but still, out jumnp the mother Grundy's who probably have no experience with this plane or the hardware supplied.

The Funtana 90 airframe can handle large engines without a problem. Mine flies with a Moki 135. It started life with a GMS 120 in it. It fluttered at low to medium pace in a strong headwind. I landed it with both aileron gears stripped. The fix is as the initial poster pointed out quite correctly, is to ditch the rubbish plastic control horns which belong on a 3 d fun fly and fit some 50 cc size control horns. There are three 135 powered F90s with this upgrade and teh same Hitec 635 servos, that get the cr@p flown out of them and are overspeeded on conventional wisdom, without any incidents at all. The simple answer is that H9 specced below par control horns on a plane with barn door size ailerons. So, no, the fact taht it had a Saito 180 in it was not the reason it fluttered in a down line.