Had a friend that used an alternate hinge on his, got aileron flutter and H9 did not want to discuss any warranty issues, because he didn't use their hinges. The early versions of this plane had major issues with the strength of the servo mounting design. Many of us that built the early version removed bottom covering and beefed up the servo mounting area with light ply and webing. Also the original design of the ball pivot going on the flimsy contro horn they have, could also flex causing flutter. Most of us used stronger hardware, 130 oz. in. metal gear, double BB servos on the ailerons and rudder and 90 oz. in. servos on the elevators. We even have a few of the rich guys using 8411's or 8611's, but this seems like overkill. We also used the original H9 CA hinges, sealed all the surfaces with clear covering and fly them like we stole them. No problems so far, just keep your speed down on the down lines. Great, neutral, responsive plane, lots of fun. The OS .90 FX with a APC 15X6 does pretty good, but the new hyp .91 OS pumped helo engine is awesome on this plane.
Have fun and happy landings.