Last Saturday, my 8 year old son participated in his first Space Derby with his Cub Scout pack. Many boys, parents, siblings, and Cub Scout leaders attended the event. What is a space derby? Well, it’s probably a little different than you imagined.
Every Cub Scout receives a Space Derby kit through their Cub Scout pack. The kit consists of balsa wood that each participant will use to form the body of a rocket. There is also plastic material in the kit that can be cut to form fins for the rocket. This is where it starts to sound a bit strange. There is also a propeller in the kit. To propel?!! I thought this was a rocket? Well, it’s supposed to look like a rocket, but the propeller actually powers the rocket. Cub Scouts race their rockets four by four. The rockets hang horizontally from a fishing line and the propellers are powered by a rubber band that comes with the kit.
Rockets are judged in three categories; speed, beauty and originality. It quickly becomes apparent that the main thing that makes a rocket fast is its weight. Since all rockets have the same power and windings the same, the lighter the rocket, the faster it will go. However, if you make your rocket light, you risk structural failure when the rubber bands wrap. So there is a balancing act to have a light but strong rocket to have a fast one.
My son and I decided to go for the beauty category as this was his first space derby. We wanted to get an idea of how the other rockets would behave in terms of speed this time. We follow the instructions in the kit and start by gluing the two balsa wood halves together. Later we use a very coarse sandpaper to start making the shape of our rocket. I later found out from some of the other parents that a potato peeler does wonders for cutting through the wood of the body to get the rough rocket shape. Not having this information to begin with, we used sandpaper. Once we got the basic shape we wanted, we used finer sandpaper. We switched to 400 grit sandpaper and finally to 800.
Next, we spray the rocket with primer. Once the primer was completely dry, we sanded it with 800 grit sandpaper. Next, we added another coat of primer and sanded again. We continued this process until the rocket body was smooth enough to satisfy us. I have a friend who said that he should have used a sanding primer. He says that he would have filled the cracks in the balsa wood with only one or two coats. I’ll have to take his word for it. I used normal spray paint primer…the cheap stuff.
Once we finished priming and sanding, we sprayed a coat of red candy over the bodywork. When spray painting, there are a few tips that will make a big difference in how your finished model will look. Spray paint only in a well-ventilated area. It is important that you hold the spray can the correct distance from your model…6 inches is generally recommended. If you bring it too close, your paint job will bleed; too far and your paint job will have an orange peel effect (it will look rough and dull). Keep the can moving as you spray…again, spending too much time in one place will result in runs and a not-so-good paint job.
By spray painting your rocket you can create a fuselage support with a coat hanger. This prevents getting spray paint on your hands and fingerprints on the fresh paint job. Make sure you have a safe place where you can put the end of the hanger, keeping the paint fresh and not touching anything until it dries. Allow enough time for the paint to dry (30 minutes) before adding a second coat or (2-4 hours) before touching the rocket body, depending on humidity.
Once the first layer is dry, we add a second layer of candy apple red. We painted the fins and propeller chrome after priming. Since we didn’t have any stickers on hand, I used silver and black markers to draw lightning bolts on the mailing labels. I then cut out the lightning bolts and glued them to the body of the rocket. My wife used a fine tip black marker to add the Captain. Justin Rodgers at one end of the rocket’s tail.
Justin’s rocket won first place in the beauty category. It did well in terms of speed, but we will definitely make a lighter rocket for next year. I hope you found some useful tips in this article to build your own space derby winning rocket.