Only a theory, but during my post mortem I noticed two grooves in the leading edge of the stock rudder that lined up with the rear of the fuse. As you commented, Eric, none of the aircraft you have been commenting on have the stock rudder. I wonder if the unsupported section of the hinge points between the rear of the fuse and the rudder are causing some kind of vibration. I never heard anything remotely like flutter, which I definitely heard when my Rev Pro came apart. My Impact had never been snapped or spun. It did have a horizontal stab failure where the aluminum tube sheared off right at the edge of the fuse. I replaced it with a carbon fiber tube. The stab landed in a swamp. Thanks to Dave Snow for donating his stock stabs.