RE: ESM 82
My Hurricane has been great. The retracts are fine, but you need to keep the doors off or use some method to rotate them. I just used a wood block attached at the base of the retracts that align the doors when the are extended which works fine. The other thing to make sure you do it get the flaps as far towards 90 degrees as possible or the plane tends to balloon. On this wing they need to act more like speed brakes than flaps.
I think you will have issues trying to fit a 50 cc engine in the cowl. I had trouble trying to fit a Saito 36 in mine and it's much smaller. I would recommend you try and find a low profile engine like one of the evolution engines (26 or 30 cc) which may fit better.
Jeff