With three fins firmly glued in place I stood the Ranger upright, with a dowel support keeping it from falling over. I found it stood just slightly off vertical on the three fins. So what to do: Glue the fourth fin on such that the rocket doesn’t wobble, but leans a bit? Or such that it does wobble, but doesn’t have a built in tilt? I opted for the second, shimming just slightly (a piece of heavy cardstock under just the outer corner of one fin). Then I glued the fourth fin on. The result does wobble just very slightly. It’s fine.
I glued the launch lug on, a 2″ long, 3/16″ lug centered 5″ above the end of the body tube. I also attached the shock cord… using a trifold mount. No, really. It’s not what I usually do, but in this case it’ll be good. It doesn’t constrict a BT-60 much. The shock cord will be harder to replace than if I used a Kevlar leader, but certainly not impossible, and I may never need to replace it anyway. The only good way to anchor a Kevlar leader I could think of would have been to attach it to a plywood chute shelf, a part I would’ve needed to order and wait for, and I decided the trifold mount was good enough. Minor catastrophe occurred when I started doing the fin fillets. Sometimes I’ll mask for fillets, sometimes not, depending on what I feel like at the time. This time I masked, using blue tape, and when I pulled up one of the pieces of tape, half the fin paper came with it!Yikes. The glue stick held, no problem there, but the thin top layer of the fin paper just peeled right up. I’ve never seen fresh blue tape do that before. And I’m not going to see it again, because I’m not going to give it the chance. I did the remaining fillets without masking. As for this fin, I think I can fix it easily enough.