I am building a LOC Precision 5.5" Big Nuke rocket. Instead of building it with the stock 75mm motor mount tube (MMT), it will have a 4 motor cluster consisting of a central 54mm MMT and 3x29mm MMT.
Details
The Big Nuke is a 5.5" plywood & cardboard rocket from LOC Precision. I am tossing out the instructions and modifying it to fly as a clustered rocket with airstart capability.
Files
5.5in LOC 54mm 3x29 - with cutout.dwg
5.5" Centering Ring for central 54mmt and 3x29mm. 9.4mm holex3 for 1/4 brake line to use as conduit for airstarts. Notches to fit fins.
Cardboard body tubes are super easy to work with. I used an exacto knife to lengthen the fin slots and remove the rear of the slot. I'll be building the MMT and fin section outside the rocket and then sliding in as one assembly.
Here's a dry fit of the assembly in the body tube. The extra holes in the rear centering ring are for 1/4" brake conduit. That will allow me to run igniters from the outboard 29mm motors to the electronics bay in the middle of the rocket, for use in airstarts. Not added yet are additional holes needed to mount 1/4" flange nuts for motor retention.