Brief:

This is the third rocket I built to enter the EMRR Spaceship Design Contest. This looks to be a simple 3FNC rocket with one heck of a span and some interesting engine pods.

Characteristics:

• Height: 24 inches Fin Length: 6.8 inches Weight (without engine): 5.9 oz
• Motor Mount: 18mm (single) Recovery: Parachute

CLICK ON ANY PICTURE TO ENLARGE Solar Flare Characteristics Height: 24" Fin Length: 7" 18mm Motor Mount 5.9 oz empty

Construction:

The following are the major components used:

Narrative:

I started with a left over kit rocket (Surefire X-19) I had from a summer class I taught. I built the engine mount without the engine hook and placed an engine block at the edge of the tube. I then glued one center ring at the forward end of the tube and the other in the middle. Once dried I glued it just inside the BT-50 leaving the engine mount sticking out over an inch. Using Matt Stum’s Template Widget, I created a transition/boat tail from heavy weight paper and glued it on.

I sketched a fin design on a piece of matt board. When I had a design that looked like the photo, I cut it out and used it as a template. Because of the overall size of the fin and the balsa I had to work with, I cut the fin in to three parts. Hopefully this will allow the fin to be stronger.

Using the fin template and some modeling clay, I created one half of the engine pod. This gave me a positive to make a mold from. Using a plastic dish with a flat bottom (mine was the blister pack from a video card) I sat the clay mold inside. I then lightly sprayed ‘Bakers Joy’ over the mold and dish to act as a release agent. After mixing up a small amount of ‘Plaster of Paris" I pored it over the clay. I let it dry over 24 hours before taking it out of the dish. Once out of the dish I carefully removed the clay and trimmed any excess that seeped in. I let the mold dry another day.

Using Crayola’s Model Magic and the mold, I created 6 engine halves. I allowed them to dry one day before trimming. Trimming the sides was easy enough, to saw them to the thickness I wanted, I used the mold. I placed the halves back in the mold and carefully sawed the excess off. The Model Magic was not dry in the center. They needed another day just to dry.

I attached the fins (without pods), shock cord, and the launch lug to the body tube. Using wood glue I place the pods on the fins and secured them in place with painters tape. Once dried, filled any voids with body putty and sanded smooth.

Because of the size of the fins I created paper fillets that went from pod to pod. I took small sheet of paper and spread white glue thinly over one surface. Then I carefully placed it on the rocket, trimming where necessary.

I began painting by coating the whole rocket with a coat of gray primer. Taped off areas and painted the gloss red. Then I painted the design on the nose cone and body. Finally I gave the engines a coat of gray with black detail. I also created a removable display cap made out of the foam clay.

Now is the time to see if it will fly. I put the design in to RockSim and found out it is very marginal. The stability was brought up to over 1 by lengthening the body tube 3 inches. I found a small piece of BT-50 and added 3 inches to the 15 inch body tube. (To avoid this splicing start with an 18" BT-50.) Since I hadn’t attached the shock cord yet, I tied it to the tube coupler before attaching the 3 inch extension.

Paint’s dry, chute and wading is loaded, an Estes C6-3 engine is friction fitted with igniter. Now I wait for a clear, calm day to launch.

After the first launch the body tube suffered some damage. I split the tube and put in some reinforcement. Added a longer shock cord and attached it closer to the nose cone. The landing of the second launch caused a stress crack along the body tube and fin. I also lost the lower fin tip. The impact of the third launch cause complete separation of the fin from the body tube.

Overall I like this rocket. I like the slow laboring liftoffs. I’m sure this will be repaired and flown again, for now it’s retired till summer.

FLIGHT #1

FLIGHT #2

FLIGHT #3