So you want to make a model rocket. This project is not really expensive with the engine being the largest cost (ca. 10€ per engine in a pack of ten). It is so easy your child could do it with only a little help of an adult.
Step 1: Tools
Cello tape, double-sided tape, heavy paper (>250g/m^2), rocket motor (weco or Estes, easy to find online and in some museum stores), knife, ruler, cutting board, wooden tip (not necessary)
Step 2: Prepping the Paper
In this step we will prepare our first sheet of paper (A4). You need to roll it up along the long side, that way it will be easier to roll it around the engine
Step 3: Insertation of the Engine
You roll the paper snugly around the engine with the nozzle-side of the engine to the outside of the rocket. If you get to the last 5 cm of the rolling, you apply some double-sided tape to the edge, that way it will stick to the other parts of the paper. It is also possible to do this with glues like pritt.
Step 4: Finishing the Tube
We now take the engine out of the tube (if that is possible) and make sure our borders are kinda clean. We also cello the edge of the tube for aerodynamic properties,
Step 5: Engine Preparation
Now the engine has to be very tight to the tube, we achieve this by adding some layers of tape until the engine is really tight and you can't move the engine any further. Try both sides of the tube for the one with the tightest fit.
Step 6: Nose Cone
You can either buy a cone like this one, that way you can also use a "parachute", If you want any explanation to that, I'm eager to make an instructable about that also. The other way is to use the paper method you see in the pictures, again, if something isn't clear, you can always ask me.
Step 7: Wings
The wings aren't really that necessary, so you can play with them a little bit. I used a square of 5 by 3 cm,but they could've been larger. You can either use four or three wings. Four are easier because that way, you can use your instinct of straight corners, but the
three wings are also possible.
Step 8: Finishing Touches
You can draw on your rocket to make it personal.
Step 9: Tips on Launching
You can launch the rocket either with a platform you can buy online or in some model stores. For the launch you can either use an electric fireworks launcher or the fuse that came with the engine. Make sure you have at least three to five seconds of fuse and that you rocket is stable (maybe with a platform using drinking straws, if you want me to explain that, just ask).