| |||||||
Making the RocketsMaking the paper rockets is really what the whole point of the exercise was. On a rainy day, with some paper and tape, paint and pencils, children of all ages will be kept occupied for ages. And it adds a whole lot more excitement when the rain stops and you can go and launch them. There are many ways to skin a cat and many ways to build a paper rocket. The key points are making it fit snuggly on the launch tube, have a weighted nose and some fins at the back. The length and weight of the rocket will also have an effect on the rocket's performance. All these things can be altered to squeeze more performance from the rocket but for very young children, it is more important to have a design that is repeatable as there is nothing more disappointing than having rocket that does leave the launchpad when you press the button. So here is my design for building small paper rockets that should give repeatable results. To build the rockets, you need:
A spare length of launcher tube is very useful to build the rocket around so cut up the rest of the crab-net pole (or use another length of 15mm copper pipe). Masking tape will take paint better than sellotape so that is what I have tended to use. Making the FuselageHalve the A4 sheet width-wise. Use one half to make the fuselage of the rocket by rolling it around the pipe and taping the seam with masking tape. I did this in several small lengths but made sure the whole seam length was covered. Run a band of tape around the top of the paper tube. Do the same for the bottom. The fuselage should fit snuggly over the tube and be able to be slid up and down with a little friction. Too loose and rocket will either not fly or go a very short distance, too tight and it may stay on the launcher. As you get more experienced, try making one end slightly tighter than the other as this gives a little leeway with how far you push the rocket over the launcher tube to get a good launch. Slide the paper tube along the pipe so it is flush with the end of the tube. Put a length of tape over the end of the tube and wrap the ends over without leaving any gaps. Wrap a band of tape around the top of the tube to prevent the end-tape coming undone. Now put another piece of tape over the end, at right angles to the first and wrap the ends over again. Put another band of tape around the end to hold everything firmly in place. You should now have a tube that is only open at one end. Making the NoseconeThe nosecone is made from a triangle that you get by folding the second half of the A4 sheet into triangles twice. You actually get 4 triangles from this piece of paper. Wrap the triangle in a cone as shown and fix with tape. Spiraling the tape is generally better than applying it straight. Make the diameter of the cone so it just fits over the fuselage, you dont want a large overhang. Cut off from the base of the cone until it looks right. The nose-cone needs a bit of weight and also a bit of strength as it tends to get crushed when the rocket lands. Cut up some small pieces of tissue and stuff them to the very tip of the cone using a pen. Add more tissue (and any scraps of paper and tape on the table) until the nosecone is suitably stuffed. Leave a rim so that the cone can fit over the fuselage. Fix the nose cone over the blanked-off end of the fuselage and hold it in place with two or three lengths of tape that are spiralled down from the cone to the body. Making the FinsThere are many designs of fins. You may choose 4 fins or 3. The fins can be fiddly and those shown here are rather flimsey but are quick to produce. Cut a length or two of paper from the flat-strip left over from paper after cutting out the nose cone triangles. About 2cm wide is fine. Wrap the tape over the strip and leave two ends overlapping as shown in the picture. Cut off any excess paper and stick to the rocket near the base using the overlapping ends. I made three fins like this and spaced them equally around the tube. And that is it. Paint as necessary but it may be worth trying a test flight first as taking the time to decorate a rocket that does not fly may be a bit frustrating. Using the above technique, I have found the rockets reliably launch with a launcher pressure of 2-3 bar which I'm very happy with as I do not want to increase the chamber pressure more than I need to. Incidentally, 3 bar gives a very good chance of launching a rocket a good distance. Increasing the pressure more often than not leads to the rocket popping on takeoff! | |||||||
| |||||||