Joe:

The flight surface covering is White Ultra-coat.

To Rich and others,
A good observation on the down thrust and it's potential affect on Stab failure, I just wish to add that I have MANY flights on my RB now w/ the OS 1/60 FX , w/ stock down and Rt. thrust, with a stab that has a BALSA root rib and I have had NO issues in this area to date.

I believe that one other aspect that is possibly being overlooked is Elevator Flutter resulting in the stab departure.

To insure fluter does not arrive at your door step, make sure the elevator pushrod system has NO PLAY in it and that when installing the Elevator to the Stab., NO GAP should be present in the hinge line of these 2 components. If when your done hinging, you have a gap, cut a small strip of the white Ultracoat or clear PVC packing tape and seal this gap on the bottom of the surfaces. GOOD insurance but NO substitute for any play in the pushrod system.

Best of luck to all and a Happy Holiday Season.