Quiet isn't it?
Well I'm totally stumped. It looked so familiar when I first saw it but I can't find anything to quite match that tail. Even looked at trimotor's just in case the wing engines are hidden from this angle!
Not been through Aerofiles yet, but short of going through every page it would be a difficult one to do a search on. Nothing in Aviastar.
Going to have to leave it to others - will check in again later.