I am wondering if anyone can tell me if there should be a bulkhead ahead of the prop in the spinner of my 360.  The fiberglass spinner seems too flimsy to me.

Jim,

 

Hartzell Prop?  If so, consider my 320 experience:

 

The spinner back plate absolutely requires doublers (available from Lancair) and the rivets should be bucked, not squeezed.  In any event, my back plate doublers shed rivet heads and cracked again and again.  My glass reinforced spinner also deteriorated.  One reason is that the back plate is often dished when stamped and it flexes.

 

Two years ago I bought the aluminum spinner from ACS and spent several long days preparing it and its back plate (adding the doublers for extra safety).  I turned a 1/4" thick nylon bulkhead on a lathe and installed that to the prop piston cap.  I love my shiny polished solid aluminum spinner.  There is no cracking, etc.

 

So, at a minimum, consider constructing a bulkhead for the spinner.  However, not everyone has problems with the original Lancair spinner.