My TopCap is a wonderful performer but at high speed (in a dive with an OS 50SX), the tail has a bit of waggle. Thin zapping the parts of the middle/rear of the fuse will help, just don't get any CA on the pull pull lines.

I didn't have any tail waggle until my 100th or so flight... after a few hard landings and lots of hard snaps, etc. Once I thin CA'ed the fuse, the plane was fine for a while... and then I just CA'ed the back again.

Eventually, I just wanted to test how much rudder flutter the airplane could take... so I put the TopCap in a power dive and managed to have the rudder flutter itself completely off. Now I use the plane in combat sans rudder.

See video of the TopCap in action at the link below.

Yours,
Juhan