My flip 3D flies great with my OS FS 70 Ultimate. It hovers at about 1/2+ something throtle, this engine can pull it out of hover easily but not like a rocket. It can flip & hover and waterfall very well, you need an aft CG and large elevator throw, mine is about 50 degrees. Just try to build it as light as possible. Use light batteries and a lighter landing gear. I ordered a carbon one from Carbon Copy UK which will give me better ground clearance as well.

I currently use an APC 13x4W prop with 25% Ni Cool Power, I am planning to use 14x4W with 30% Ni. Last week one of my rudder metal hinges went off, there was a cut on the metal near the pin. This due to the horizntal vibration of the rudder/fin, just check how it vibrates horizontally. Only two hinges can not support this vibration amplitude. I replaced both of them with three Dubro 1/4 scale heavy duty hinges and I also put some wooden sticks and a thick decal over them for further robustness.

Flip 3D has a very ROBUST structure one of my mates lands it with the tail gear (harrier landing) and sometimes smashes his props and landing gear on the ground without any cracks on the mainframe. That's why it is heavier than similar models of its size such as the Madness which comes about 300 to 400 grs lighter. So, don't be afraid, it is not that fragile. At the end of the day it is made in China so it is a quite heavy structure.

With regards to vibration it vibrates a lot at lower RPM. This thin film and relativelly light structure make it behave as a "loudspeaker". Also the Elevator and Rudder extension leads can create further noise. What I did was to stick some foam with tape on the connectors of the leads in order to eliminate the sound created during their coliisions with the fuselage.

Nik