RE: Props for a Magnum 52
i have the O.S.52 and i use a 11 x7 scimitar for sport flying. the 12 x 6 apc is a great prop and i have a few of those also for sport flying. for 3D? wouldn't know... can't imagine using the 52 for 3D. but if i had to guess, a 13 x 4W would be a good choice.