Summary: on them The sketches show the arc of the nascent fin in the fuselage skin and the dashed angled line in the lower sketch is meant to show where that becomes the curved fuselage top again Basically in copying Paul Stewart s creative design specifically per his scheme to avoid crawling into the black depths to administer BiD flanges and John Cliff s version to make the
Image Dimensions: 727 x 938
Image originally found here.