This is a Larry Brand design that I assembled from parts contained in a LOC Precision Lil Nuke kit and an extra length o' 54mm tubing.  LOC 54 mm tubin' is motor mount grade so it's a bit thicker than most.  I also ordered a 6" long payload bay kit t' complete t' build.

Larry's article on t' original Auracle 54 is sketchy on details and so I relied on t' photgraphs accompanyin' t' article.  When all was said and done, I'm happy with t' way it turned out.  In retrospect, shiver me timbers, I will never again attempt a tube fin with tapered ends.