This past 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 what 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 propels the rocket. Cub Scouts race their rockets four at a time. The rockets hang horizontally on a fishing line and the propellers are powered by an elastic 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 lightweight, you risk structural failure when the rubber bands roll up. 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 perform in terms of speed this time around. We followed the instructions in the kit and started by gluing the two halves of balsa wood together. Later we use a very thick sandpaper to begin to make the shape of our rocket. I later found out from some of the other parents that a potato peeler works wonders for cutting through the wood of the body to get the rough shape of the rocket. Not having this information to begin with, we use sandpaper. Once we got the basic shape we wanted, we used a finer sandpaper. We switched to 400 grit sandpaper and finally 800.
Next, we spray the rocket with primer. Once the primer was completely dry, we sanded it with 800 grit sandpaper. Then we added another coat of primer and sanded again. We continued this process until the body of the rocket was smooth enough to satisfy us. I have a friend who said that he should have used a sanding base. He says that he would have filled the cracks in the balsa wood with just a coat or two. I’ll have to take his word for it. I used regular spray paint primer…the cheap stuff.
Once we finished priming and sanding, we sprayed a coat of candy red over the body. When spray painting, there are a few tips that will make a world of 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… about 6 inches is generally recommended. If you move it too close, your paint job will have runs; too far and your paint job will have an orange peel effect (it will look rough and dull). Keep the can moving while you spray…again, spending too much time in one spot will result in runs and a not-so-great paint job.
By spray painting your rocket you can create a fuselage stand with a hanger. This prevents spray paint from getting on your hands and fingerprints on your fresh paint job. Make sure you have a safe place where you can put the end of the hanger, keeping the paint cool and not touching anything until it dries. Allow sufficient time for the paint to dry (30 minutes) before adding a second coat or (2-4 hours) before touching the body of the rocket, depending on humidity.
Once the first layer is dry, we add a second layer of candy apple red. We painted chrome the fins and propeller after priming them. Since we didn’t have stickers on hand, I used silver and black markers to draw lightning bolts on the mailing labels. I then cut out the rays 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 Rockets’ tail.
Justin’s rocket won first place in the beauty category. It did okay in terms of speed, but we’ll 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.
