The rocket motor is one of the most important parts of your rocket. Motors are fairly similar in power and size and are available from model stores or online. They are classified by diameter and class. Diameters range from 13mm-29mm and Classes are from ¼A, ½A, A, B, C to D. Each increasing letter having twice the thrust of the previous one. The D motor is commonly used in UKAYRoC rockets, often in clusters. Please see the UKAYRoC 2013 Motor List on the UKAYRoC website for details of which motors are permitted for the Challenge.
There are two main types of rocket motor available to you:
Black Powder – These are the most common types of rocket motors and are mainly used for model rocketry. There are two main companies manufacturing these, Estes and Quest Aerospace. Estes motors are readily available in the UK, Quest motors can be harder to obtain. These do not require any documentation to use, just consider safe storage and transportation.
If you think you need more thrust than 20Ns and you don’t want to follow the clustering route, then you will need to consider using the more powerful propellant.
Ammonium Perchlorate – These are commonly referred to as AP motors and are mainly used in mid and high powered rocket motors. These are a totally solid based rocket fuel and although they are classified by HSE as explosives, they don’t actually explode, they just burn fast.
In order to use AP motors, you need a document called a Recipient Competent Authority Transfer Document (RCA) from the Health and Safety Executive (HSE). This allows you to move your propellant from one place to another, for example from your school to the launch site. In legal terms, move includes not only from the shop to your car and to the launch site but also from a shop at the launch site to the launch pad itself. Without it you will not be able to use AP motors. Please make sure you complete the relevant section in the registration form.