You guys are great. I appreciate all the info so far. I happen to agree that if it does what you want that is all that counts. Maybe I am reading into one of your answers but when you said internal ducting were you making a reference as to the Byron does not have internal ducting on that particular model? I am assuming you were just generalizing . I have never seen a Byron F-15 so I do not know whether it is internal or external ducting. I would hope it is internal for appearance.