Well then. Sprinkle me with bread crumbs and bake me for 40 minutes. ZK-CKE has cracked it again - first shot. Well done.
Below is a counter weight, which would have been the second clue.
It is indeed the hub of a Hamilton Standard propeller.
The prop is hanging off a Jacobs R755B2 (affectionately known as the "Shaky Jake")
Photos taken at Ashburton 15-01-2010.
ZK-RDK c/n 75-5164 was built for the USAAF and allocated the serial 42-17001 before transferring to the US Navy as Bu61042. It in due course became N1391V.
It became ZK-RDK on 17-03-2009; the registration being the initials of its owner Richard D King.
Another fish in the mail.