Construction

The Goblin kit does not include a parachute or a motor retention system. I chose to create my own motor retainer by attaching two mirror clips to the bottom of the motor mount. I used a 36" hot pink chute and a 12" Nomex chute protector from www.RocketChutes.com.

The kit instructions were very good, and they can be found online at http://stores.whatsuphobby.com/catalog/goblin3instructions.pdf. The instructions include photographs that help guide the build process.

I started construction by sanding down the shoulder of the nosecone. This step took a very long time, much longer than expected, in order to get it to fit into the body tube. The nose cone also has a slight seam from the fiber glassing; however, it sanded off easily.

I then installed the eyebolt and hardware into the top motor mount centering ring, tightening the nut with a 7/16" wrench and securing the threads with epoxy. I used the 5-minute epoxy to assemble the motor mount. It is crucial to first check that the fins fit between the centering rings. I tied the shock cord to the eyebolt using a figure eight knot, and epoxied it in place. Then I tucked it inside the motor tube to keep it safe from any epoxy, as I installed it inside the body tube. 

Next, I used 5-minute epoxy to attach the fins and smoothed out the glue that seeped out the slots. It was tough to judge what was symmetrical. I added fillets to the fins afterwards, ensuring that they would stay secure, although the kit instructions did not recommend I do so.

I connected the U-bolt in the to the nose cone’s bulkhead and then epoxied it in place inside the nose cone. I did not add any weight to the nose cone.

I installed the aft centering ring such that approximately ½” of the motor tube extended beyond it, which is the minimum to install an Aero Pac motor retainer; however, to save costs, the following supplies, obtained at a hardware store, were used to create a motor retention system:

(2) mirror clips

(2) 6/32 threaded wood inserts

(2) 6/32 round head slotted machine screws with nuts

I came across a very helpful video that shows how to properly install wood inserts: http://youtu.be/tIhEqoKE8Dc.

Lastly, I added the two rail buttons, each using one nut and two washers as spacers. The kit comes with two nuts. I drilled two 1/8" holes and then threaded the 8-32 screws. I drilled a pressure hole as well.