Model rockets are built and launched using the same basic principles as full-scale rockets, allowing for such factors as drag, stability, mass and thrust. The types shown here all use pre-loaded single use engines which are ignited electrically. Lengths of rockets in this scale are generally from about 20cm to 100cm, and these models typically reach 50m to 500m altitude with single-stage engines. Recovery systems (such as parachutes) are used so that the rockets can be launched many times.
The rockets are constructed of lightweight materials such as cardboard (body tubes), plastic (nose cones) and balsa wood (fins). They are usually painted and sometimes decals are also used to complete them. These rockets can also be detailed scale replicas of missiles or aerospace vehicles.
Capturing rocket launches with a single-use camera isn't easy since these things take off like... well, like a rocket I guess! They can also be quite ferocious-sounding. If you haven't seen them in action, see if you can check them out at a local club day or similar. Model rocketry isn't a very widely known hobby in Australia, but if you have a local hobby shop who sells rockets then ask them about any associations or clubs in your area.
The basic code of practice for model rocketry is set out in most of the manufacturers' data sheets, catalogues and instructions so I won't repeat it here; likewise brand-specific information such as engine types and so forth. However I will emphasise that model rocketry is a very safe and enjoyable hobby if the appropriate rules and some common sense are used. If you participate in model rocketry then please keep it that way!
Scale model rocketry also tends to attract a lot of attention from onlookers. Many people have not seen these models launched before and usually are quite impressed by their flights. The best thing is to have at least one buddy with rockets, so you can share equipment and one person can launch while the other is preparing rockets. That way you get a decent number of launches and there are plenty of different rockets. (Also you can get some launch photographs!)
Building the rockets is also part of the fun. Some of the rockets I've made so far have been from individual kits (e.g. Estes Zinger, Tornado, AIM-9 Sidewinder and Phoenix), general parts collections (Estes Designer's Special) or scratch-built designs (Bubblecam - see part 2 of this section). Some maintenance is usually required after a launch session - fixing broken fins, burnt or torn parachutes, etc. Also there are times when rockets don't return at all - for example if you fly them near a river and air currents catch them...
The smaller and lighter the rocket, the greater the altitude it will generally reach. The larger rockets tend to exhibit a more "realistic" take-off with slower acceleration, but attain lesser altitude even with comparatively large motors. Also the higher a rocket flies, the more likely it is to encounter wind which can carry it a very long way from the launch site! Tall trees are also likely to snag a rocket on its way back down, so try to launch in an open area.
Designing rockets can be a real challenge. Study some manufacturers' designs and see what elements they have in common - certain characteristics can be altered freely, others may have unwanted effects if changed. The most important principle to remember is that most mass should be towards the nose of the rocket; fins towards the rear. This will help to ensure stable flight. Many rockets are designed with extra nose-weight (usually modelling clay) for this very reason. In some cases a rocket which exhibits stability when flown with, say, an "A" or "B" motor can become unstable when a "C" motor is used because the centre of gravity shifts to the rear. Adding more nose-weight will usually cure this type of problem.
Model Rocketry: Bubblecam (Aerial Photography)
Movie: Sidewinder Rocket in Action
(Movie is in .MPG format, approx. 1.25Mb)
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