Ronald Hatcher.

Personal notes and projects.

Classic FSI Black Brant II Kit

My friend Jim from my local rocket club sold me a classic FSI Black Brant II kit for an extremely reasonable price at the club's annual event this year. The kit is in great shape and I wanted to do it justice by building it extra special.

I haven't seen big chunks of balsa like this in a long time. The kit is really a great example of high quality from 30+ years ago but the balsa has some very deep grain so the finishing stages will be a bit more challenging.

The kit is a 1/8th scale model of the Black Brant II sounding rocket and since it is long out of print, I've documented as best I can for posterity.

Starting with capturing all of the parts in Fusion 360, which made it easier to understand the build process and also to create a simulation in OpenRocket.

The design details are over in the project page. This is a cutaway view to get an idea of the internal structure.

Motor Mount

Overall, this is a well understood design and straight forward to build. I like the stuffer tube approach. Especially since the airframe tubing is very lightweight. The build and individual steps cover the process in detail.

The only required modification was to adapt the originasl motor mount to 24mm. The FSI motors that the rocket was designed for were 27mm.

This is a view of the motor assembly with the additional centering rings and the 24mm motor tube.

I took the opportunity to add an Aeropack retainer to the motor mount, is a great benefit when using 24mm reloads. I cut the centering rings from 6mm plywood and the motor tube is 24mm standard issue Estes.

Using JB Weld to attach these componets gives a good solid mount for the F motors I have in store for it.

Recovery System

I added my own recovery setup, replacing the original with a spliced kevlar cord and heavier weight swivel.

Finishing

I really wanted to do a good job on the finish. I used a lot of filler and sanding to get the balsa smooth. I used a combination of sanding sealer and primer to get a good base for the paint.

All the details are in the build section and I'm really happy with the results.