26 MM UPSIDE DOWN WITH EMPTY TANK SHOULD BE FINE. I HAVE IT AT 35MM WITH FULL TANK.
FLYS GREAT BUT TENDS TO BOUNC ON LANDING. TAKE OFFS ARE EASY IF YOU DO IT RIGHT. HANG ONTO FULL UP ELEVATOR AND FEED IN POWER SLOW AND AS SPEED BUILDS YOU CAN RELEAS UP ELEV.KEEP WINGS LEVEL AND LET HER TAKE OF BUY HERSELF. NEEDS PLENTY SPEED.
I AM USING A OS 61