Category Archives: Tips and Tricks

Ooops, I Broke a Fin!

Ooops wasn’t the first word that I actually used.

The story of how I got to this point is long and boring. But at the end of that story, I had a nice, all carbon fiber 54mm minimum diameter screamer I was affectionately calling Doppler Shift. I launched it on a J415W at December’s Snow Ranch launch and promptly lost it, despite having a Walston RF tracker onboard.

I was hacked to say the least, but I managed to recruit our club president to go back to Snow Ranch with me on Sunday and hike the acres with the receiver looking for it. As luck would have it he found it, but it managed to find the one rock on that hill and broke a fin.

This is a minimum diameter rocket. The fins are surface mounted, and since it was originally designed to fly on an EX “L” motor, they had to be strongly attached. The original work was done by James Marino, and he used both fiberglass and carbon fiber to attach the fins. Only one fin was damaged, and it was not actually broken, but the fin to airframe attachment was broken. The layups where still intact, and were still holding. So I wondered “What should I do?” This article is about what I did, and how it worked out.

Continue reading