Well, I think I have confirmed what is the task I like even less than body tube filling and sanding: hand tapering fins. With the motor mount figured out, I started preparing the fins for the scale leading edge taper. Using the instructions as a guide, I ran some masking tape from the root-tab corner, to the aft corner of the tip. Then, I marked a centerline on the leading edge and roughly drew the taper on the inboard and outboard ends to help me keep the taper centered. A belt sander would make quick work of this chore, but I’m doing it by hand, sanding with coarse sandpaper. This is similar to what I did on my Estes Black Brant II, and while it only has three fins versus the Doorknob’s four, those fins have double tapers! I should be grateful for this relatively simpler chore, but it’s still not very enjoyable.
Thanks to
Les' post above , I tried making a quick and simple tapering jog out of scrap wood I had laying around in order to ease the operation. I attached a small strip of wood to a scrap 1”x6” to create an edge that a sanding block can ride against. After calculating the angle of the taper based on the length and fin thickness, I could use that to determine how far away from the guide to set the fin for the taper.