Mike,

I am just building one and am a little surprised, based on my experience so far, that it is showing that much vibration down the back. The relatively hard mounted motor may contribute. Have you been through prop balance etc?

On the bracing, can you be a little more specific on exactly where ithe fatigue cracks are? Armed with that I will have a good look at mine and think through bracing/stiffening options.

Glad to hear it flies well -- I look forward to getting mine in the air.

David