Sorry that I forgot to mention that it's a 12x8 so I would imagine a 13x4W would swing just fine. I've only had the diesel for 3 days now and am amazed that a .46FX would turn that prop like that. I had my Saito 72 turning the 13x4 on my Magic Extra until the midair with the earth... Oh well, it needed that dirt bath anyway...[&o]