LOC Magnum

These are some details of how I built a LOC Magnum for dual deployment.

The following PDF files have the original design and the new design
Original
Modified

Glassing

I started this project by glassing the 5.5in airframe.

The original design of the Magnum has one main tube 45in long.
The new design called for this airframe to be cut into several sections.
One 25" long that will form the main parachute compartment.
One 19in long that will form the drogue compartment.
And a strip one inch long that will be glued into the middle of the e-bay.

I started the glassing project by peeling off the glassine outer layer.

I put a Kevlar strip on the end of the tube and glassed over it.

The next day I cut the end flush.

Next I fiberglassed the inside of the coupler that would be mounted in the fincan.
First I brushed epoxy on the inside of the coupler.
I lightly rolled the glass that would go inside the coupler and placed it inside and carefully unrolled it while keeping it aligned and smoothing it with a scraper(fake credit card, get lots in the mail).
Once all squeegied out I inflated balloons inside.
I used two since one wont reach all the way.
This makes the ends very nice and smooth so I can easily get the CR to fit well.

Attaching fins

Since this rocket has outboard motors I tossed out the short MMT's that came with the kit and used a section of 29mm Phenolic tube I had.
I also made a new CR for the aft end. I did this for two reasons.
1) Since the core motor would be using an Aeropack motor retainer I had to move the outboards as far out as possible.
2) I wanted two CR's to support the outboards, as shipped the design was only going to use one.
Because the upper CR for the core MMT needs to be installed inside the coupler, I used the one that came with the kit as the aft CR.
I cut holes for the outboard MMT's in it and also cut new holes in the original aft CR to be used at the top of the fins.
I started by pealing the glassine layer off the MMT where the fins would be because I was going to glass aross the MMT from fin tip to fin tip.
I aligned the CR's with the outboard MMT and tacked them in place on the MMT with CA.

Then I positioned the fins and tacked them in place with CA.

I then applied fiberglass to each set of fins across the MMT.

The next morning, before the epoxy fully cured, I trimmed the edges with a hobby knife.

Rail Guides

I made two blocks for mounting the rail guides.
I cut two pieces of 1/2in plywood and used my bench sander to sand them to the tubes inside shape.

Then I drilled a hole in the center for the tee nut to go through and pressed it in place with my vice.

I marked the center point between the fins on the CR then glued the blocks in place.

Once both were installed I placed my angle across them and marked three points on it to help me locate them after the BT is installed. I marked the center of both tee nuts and the bottom end of the aft CR.
This way I can easily locate them later.

Fin slots

I like to cut the fin slots after the tube is glassed.

I made a jig to hold the tube so I can cut it on my table saw.

First I put the assembled section of the fincan into the BT and marked the locations of the fins.

Then I mounted it into the jig and made the cuts on the table saw.

Fincan

Now that the lower BT is slotted I can test fit the pieces of the fincan.

But first I needed to cut the upper CR. I used my router circle cutter to cut the outside of the CR then used my fly cutter to cut the 54mm ID.

I assembled the fincan with the CR, it was a perfect fit.

Then I installed the conduit for the airstarts. Which can be seen in this image of the fincan.

Electronics Bay

The e-bay needed a hatch to mount the altimeter.
I cut the hatch from the end of the BT so the coupler could slide in/out with the hatch installed.

I put a tee nut on each corner to hold it on.

The altimeter fits nicely on the hatch.

The bulk plates for the ends of the bay are made from one piece of 1/2in ply.
I cut them stepped so they would seal the bay and be self centering.
I used my router to make these cuts.

They fit very nice

Nosecone

I cut the bottom off the NC and glued in a bulk plate.

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