This semester I joined the Ramblin Rocket Club at Georgia Tech and last week I had a successful launch and recovery of my first rocket.

The basic rocket structure is made up of several parts. The main body is a mailing tube. At the base of the rocket there is a smaller tube centered inside the main tube with centering rings. Around the base are three fins made to fit inside the rocket all the way up to the smaller inner tube. There are slots in the fins to fit snugly around the centering rings. The rocket is split into two sections, with the bottom part holding the parachute and a shock cord which keeps everything together. The top section can be used for holding a payload, such as sensors or GPS (I did not use the payload bay for this launch).

My design and build process

It started with a design in OpenRocket (a free model rocket simulator). After coming up with a basic fin design in OpenRocket, the precise measurements were used to draw the outlines in AutoCAD. For the base of the fins however, fin tabs needed to be added (they aren’t included in OpenRocket) so the fins could reach the inner tube and fit around the centering rings. At the same time, I made the centering rings in AutoCAD. The top centering ring has two holes for a u-bolt used to connect to the shock cord and the bottom centering ring has two holes for screwing down clamps that hold the rocket motor in.

Now I took the AutoCAD drawing to Georgia Tech’s Invention Studio and utilized their laser cutters to cut out the pieces from 1/8th inch plywood.

After this, it was time to put together the fin structure. First I glued the centering rings to the inner tube. Then, I glued the fins to the inner tube and around the centering rings, using lines on a paper to keep the fins spaced as close to 120 degrees apart as possible. Later I epoxied all of the edges to make the structure stronger and more durable.

To connect the two sections of the rocket, I made a coupler out of a section of the main tube. I cut off just enough circumference to make the new outer circumference fit snugly in the inner circumference of the main tube. Then I epoxied it together along with a wooden bulkhead I laser cut with my remaining wood, and stuck it in the upper body tube with more epoxy.

Painting the rocket was straightforward although it took many more coats of black than it did of green. Since I was painting the fins the night before the launch, I drilled holes for the two rail buttons, which are used to keep the rocket on the launching rail, before painting the fins.

Launch

Early sunday morning we left for Alabama. When we got there, we put together our motors, packed our parachutes, and after a safety check launched into the overcast sky. There were 8 people launching for their level 1 certification and all 8 were successful. It was uneventful except for one rocket unfortunately landing on a power line.

Edit: Here is a video of the launch and landing of the rocket.