Cut a piece of single-ply cardboard (shoe box type) to use as a template for locating the propeller blade cut-outs in the S-601-1 Spinner. Lay the cardboard over the S-603 Spinner Front Plate and the Spinner Back Plate Assembly.
Make a cut-out in the cardboard that fits the contour of the propeller blade and that extends down both sides of the propeller blade perpendicular to the Spinner Back Plate Assembly flange. Once the cut-out is made and fits the contour well, mark and trim the cardboard along the flange edge of the Spinner Back Plate Assembly.
I also tested the nose wheel tube. I submerged it in water to test for leaks. No air bubbles. It would only hold air in the tire for a couple days, so the mystery is still present. I would have thought if there was a hole, it would still be present.
