RE: prop size for 52ccquadra?
If it was at the C.A.R.D.S show last year yes I saw it die.
By the way I made a mistake in the weight. It is not 65# but 76.6lbs. even better on a pair of now 17 year old Q-50s awinging 20X10.
He will fly it at the Joe Nall this year .