air.command wrote:This looks like a seriously cool project Mike! Definitely will be following your build progress on this one.Passaretti wrote: Worst case, I can heat fit it and then cut it off after the flight.
What if you split the fin can along the root edge of one of the fins. Weld one fin along one edge of the split perhaps with a right angle bracket as well and then weld a right angle bracket along the other edge of the split. Then you can easily slip the fincan on the motor and tighten up a bunch of bolts along the right angle through the fin. If you tap holes in the fin (and perhaps the right angle on the other side) and use counter sunk screws you shouldn't incur a drag penalty. If you use enough bolts you should be able to tighten it so it can't come off and then you can take it off again when needed. Whether structurally it will take the load at Mach 3 is another question.
Thanks George and nice diagram!
I'm with ya' on your concept for attaching the fins and keeping the fin-can removable. My original approach was a three-piece can. See attached example. The trouble I kept running into with these concepts was the mechanical complexity and overhead of attachment methods. The drag hit could be quite high as well. I started to veer away from mechanical attachment methods: right angle, fasteners, multi-piece can's etc. and towards bonding the aluminum fins to the aluminum can using some kind of adhesive technique. A bunch of ideas were passed around for employing epoxy rivets, cf or e-glass reinforced joints etc. At the end of the day - I said F it ... I'm going to take the easy way out and have someone weld the damn things on. So here I am ... The trade is that I still need to figure out how to get the fin-can on the rocket - and possibly back off.
I have hope that there is a way slip fit and then bond the can onto the casing; using some solvent to break down the bond after the flight ...
Thanks for the comments - keep em' comin'!