Kraken Li'l Meenie

While waiting for a dry day to put a clear coat on my Screamin' Green Meenie, I decided to explore an idea that had been growing in my mind.

While building the SGM, I started to wonder about a kitbash of sorts. I am a fan of short, fat rockets and if they are low'n'slow, that is even better. I figured that putting Kraken tube fins on an SGM could possibly produce an awesome short, fat, low'n'slow rocket so I started translating mindsim to OpenRocket. The first challenge was to sim contoured tube fins in OR. Fortunately, groups of three fins of the same contour effectively simulate a tube fin, the process is outlined here. The next challenge was to get a reasonable CG for a short, fat rocket so I referenced Peak of Flight Newsletter #154. The results from OR told a slightly different story than mindsim, so I decided that the wise approach would be to start small and adjust the design from there. The end goal is a 2.6 inch version, I just have a few things to figure out.


I used the fin templates from OR to transfer measurements to a 2 fin marking guide to produce a template for the tube fins.


We now have some parts to play with. I know that the Kraken has 4 fins but tube fins are cool so more is better in my book.

The OR file will get updated shortly. I used a nose cone that I had laying around, I think that it is the BNC-50Y but I am not certain of that. I will also over ride mass and CG when I get a chance to put the finishing touches on this little guy.

Motor mount and finished assembly to come shortly.

Just a couple of items to wrap up the build.


I dug up a 13mm tube for the motor mount. Unfortunately, I had to extract it from an already completed motor mount. After removing the thrust ring was removed with a step drill and peeling the cardboard centering rings, the tube was smoothed a bit with 220 grit. I banged out a couple of centering rings from balsa sheet and papered them for a bit of reinforcement. A coffee straw was added for the replaceable shock cord and the mount was glued in place after the it had set up.


Here is the completed rocket. It is small, only 8.25" and it weighs in at 14g (no nose weight yet). I'll get some primer on it tonight and decide on recovery gear. I figure that a streamer will be the way to go since there is precious little space for a parachute.