Steve
I have run the 40XZS in an Oriental, 55in span ( 550 sq in ), motor ran well after a bit of sorting.
Found it was overcooling with the head stuck out in the breeze in the Oriental,may not be a problem with a full
cowl,5% nitro, 23% oil,( 50/50 Klotz & Castor ) stock motor as it came out of the box with a Glow Devil 300 plug,
RSM T/Muffler, APC 11x4, RPM on ground 9,900 to 10,000, used 95cc of fuel for a 6min 30sec flight ( FAI rules).
The thing that brought it to life was using the APC 11x4 prop.Uniflow tank( No muffler pressure, but has a restrictor
on the uniflow vent) motor was riching up at the end of the flight,the restrictor solved this.
Paul Allen
OZ