I was cleaning up Tsamsiyu today for an airshow this weekend, and as I was cleaning bugs off the spinner, I noticed that it seemed a bit loose - it had a definite (small) wobble to it. Further examination revealed that the rear bulkhead of our WW-151 prop spinner appeared to be moving slightly relative to the hub. After removing the top cowl and spinner dome, it became apparent that the six AN4 bolts that hold the bulkhead to the hub were a little loose. I cut all the safety wire and tightened them up, then spent an hour resafetying them (as ad as prop bolts).
My conclusion on this is that the hold the bulkhead to the hub by essentially clamping the composite to the hub. The bolts couldn't loosen - they were wired - but the material probably gave a little. The lesson here is that these bolts probably need to be checked every couple of hundred hours (ours has 300 at this point - and they weren't loose at the last annual) - either the composite is getting crushed, relieving the torque on the bolt, or it is flowing with the same results.
For those without WW props - the prop comes with the spinner and the composite bulkhead - this does not apply directly to Van's spinners.
Paul
My conclusion on this is that the hold the bulkhead to the hub by essentially clamping the composite to the hub. The bolts couldn't loosen - they were wired - but the material probably gave a little. The lesson here is that these bolts probably need to be checked every couple of hundred hours (ours has 300 at this point - and they weren't loose at the last annual) - either the composite is getting crushed, relieving the torque on the bolt, or it is flowing with the same results.
For those without WW props - the prop comes with the spinner and the composite bulkhead - this does not apply directly to Van's spinners.
Paul