Mike,

 

The rear bulkhead in my airplane is entirely glassed in and one continuous piece of prepreg.

 

By the way, I taped the tail activity yesterday during an event while taxiing as well as during run up, take off, landing and roll out.

 

The tail showed almost no movement that could not be attributed to bump in taxi way or engine vibration.  During run up there was no significant shake.  The entire plane vibrates a little when the engine is run up.  The tail activity was consistent with that vibration.

 

I did see movement that lasted maybe a quarter of a second during hard braking but it was not nearly enough to produce the "tail jump" impression that I had been having.

 

I have roughly calculated the stick movement frequency and believe it to be fairly consistent with the revolutions per second of the main tires.

 

I am seeing just about all the information I have gathered pointing to an out of balance tire assembly issue (bad tires, bad balance, bent wheel, something on that order).

 

I rechecked the main gear wheel alignment yesterday and found it to be exactly to factory specs.

 

If you or anyone else has additional comments, suggestions, questions on this issue I really appreciate it.

 

The responses from both lists have been very helpful and informative. 

 

Thanks again,

 

Jim