Drew an offset line along the top sikn and fuselage side skins, 2" from the forward edge (firewall). Then layed the top cowl behind the spinner and marked a line on the aft edge of the overlapping cowl, 2" in front of the offset line, this representing the 'edge' of the underlying firewall edge. Allowed approximately 1/8th" fudge factor for safety and trimmed the excess of the aft edge of the cowl. After carefully positioning the cowl again, determined where additional trimming should occur, and trimmed successively to align with the firewall edge. Clecoed on the top firewall cowl hinge and used it to support the newly trimmed top cowl.
Then started fitting the lower cowl. Had to cut the nose gear slot further. Also had problems positioning a strap to hold the lower & upper together.
Identified interference in the butt-joint around the inlets, And, interfence in the overlapping 'round' section behind the spinner area. Removed portions of the material and retested.
