Well, I started on the upscale fins last night...after hours of trying to figure out the 29mm design (MD or 38mm bt?), I figured I'll use 29mm blue tube first and was aiming for 38mm cardboard outer. I considered 29mm CF (I actually
got one from Rocketry Warehouse for $50 during the last BF sale); however I decided against it for now since it wouldn't quite make sense if I was going to add on 38mm parts.
So first I enlarged the fin template I have to 38mm, printed it out on cardstock, cut it out and traced it onto basswood:
Then I tried a dry fit on a 38mm tube and...it just didn't look quite right.
Turns out I thought the template I grabbed for enlarging was for 18mm fins, but it was actually for 13mm fins, so these are too small.
Yup, failure is always an option. Still suffering from a bad cold, so my brain is still a bit foggy (which made using a bandsaw take doubly long since failure is a very bad option there). I think it'll work for 29mm MD, so I may use it for that first and then 38mm after that. I'm still building modular, so I'll make it as adaptable as possible.
Other possible build parts:
-I may go with an ejection baffle, that way I can maybe have the collars screw into it and also use it as an anchor point for the shock cord (skipping the motor block since this can be MD).
-Considering using a threaded insert at the front end so I can screw on different uppers (ex. 38mm or 29mm extension)...
-Alternatively, may just drill a hole through near the top for an anchor pin for the 38mm upper and still be able to just use a 29mm nose cone straight on.