RE: Ziroli Panther
Pete,
There are a number of those planes around flying with turbines. However, it was only designed for around 12 lbs thrust from an ICDF and some early turbine conversions used 12 lb turbines and it flew fine. 18 lbs of thrust is plenty for that model and 22 lbs is *more* than enough. If you were doing a full-throttle pass with a 22 lb turbine, I'm not surprised at all that it came apart. If you went with the stock setup of servos connected to the tail surfaces via long pushrods, then that would be even more likely.
I have one that I blew up to 80" wing span and I fly it with a P-120. However, the airframe is glassed with some extra layers around the tail, I use JR 8411 servos that are mounted right at the surfaces with 3" pushrods, and I manage the throttle very conservatively.
Hardwood stringers in the tail would help, or at least select hard balsa for the tail stringers and skin. Be careful not to get the tail too heavy - one extra ounce there means about 1.5 oz in the nose. Also read the threads about the wing incidence and possibly reducing it some for a purpose-built turbine version of the plane.
Bob