Jack 211,

The 46 and the 60 both make the drum sound, it will get worse if you are running a 4 stroke with to big of a prop, I ran a 15x4W on an OS 91 FS on the 46 size, tried 14x4W and the drumming was less severe and it flew straight up, I miss mine crashed it showing off to a small crowd that had gathered in our parking lot at the club, I am going to fly this next.