Who needs model rocket kits when you've got tubes from paper towel rolls? This is a simple model rocket design that can be built, start to finish, in one afternoon, and that's including the one trip to the hobby store to buy model rocket engines. If you have all the materials already, this rocket can be built in an hour or so.
I used an A-category engine from Estes that I had been keeping around for no reason. It turns out that these engines are the perfect fit for this rocket. Could probably get away with a B engine as well. The rocket went up a couple hundred feet, and landed in good condition.
Step 1: Materials
Cardboard tube from paper towel roll or similar.
Additional, thin cardboard, like from a cereal box.
One drinking straw.
Small model rocket engine, along with stopper and fuse.
PVC tubing or vinyl tubing, (flexible plastic tubing). Home Depot has it in the ropes/chains section.
Model rocket launcher kit.
Step 2: Step 1: Put Together the Engine Assembly
So you've got your paper towel roll. How do you get the model rocket engine to stay situated in the end of the tube? The solution is to create an assembly of sorts, which fits snugly into the tube, and has a hole cut in it for the engine.
Start by cutting a short length of tubing - 2 or 3 inches. Stick the engine inside the tubing. It should be a snug fit. It is important that the engine stays stuck in that piece of tubing during launch. I glued it in place, but I would actually recommend attaching some sort of cap over one end of the tube, so that the engine cannot escape.
Next, cut two round-ish pieces of cardboard with the same diameter as the inside diameter of the paper towel tube. Cut a hole in the center of each of these, so that they can be slid over the plastic tube section containing the engine, then cut three small triangles, equispaced, out of the outer rim - this allows the assembly to slide past the fins.
Glue everything together, and set the engine assembly aside.
Step 3: Fins and Guides
The fins are cut out of a thin piece of cardboard, such as a cereal box. Cut three triangles, and then make a cut down the side of each triangle, creating a flap enabling the fins to be slid over the back end of the cardboard tube. Do this.
Next, the drinking straw. This is used to guide the model rocket along the launch rod. Cut a couple of inch-long sections from the straw, and glue them onto the side of the main tube, so that a thin metal rod can be inserted through both of them. It is important that they be aligned properly. I found it helpful to use the launch rod as a guide when placing these.
Step 4: FInishing the Rocket
All that remains to be done is to create the nose cone and attach the engine assembly. For the nose cone, roll some extra cardboard into the cone shape, glue it closed, and slide it over the front end of the rocket, gluing it in place. There will be some extra cardboard flapping around at the nose cone's base. Clip this off with a scissors.
The engine assembly can simply be slid into the back end of the rocket, and glued in place.
That's it. Please use caution when launching and be sure to launch the rocket in a spacious area.