B*gger, the 108 has a two blade prop anyway. So, not German. That really only leaves Italian (doubtful) Canadian and Australian. Can't really be Japanese, for similar reasons to the Luftwaffe demise. Got me stumped so far.
That wads a good one Gary! at first I thought it was a gondola on a blimp of airship, than I remembered the tail-gun position they put on Diamond Lil when they re-did her a few years ago.
Here's one with a lot shown, but there's little twist: