When you start multi-staging it opens up a whole new area of model rocketry. It allows you to build high performance, high altitude rockets or rockets that need to get a payload to a high altitude. Basically it has many uses. Multi-staging is a tried-and-tested technique and if you follow the instructions here you will have 100 percent reliability from your model.
A staged model has two or more motors in it, one above the other. The lower motors are detachable and they have their own engine mounts, body tubes and fins while the upper part of the model is the same as a the single staged variety. The booster (lower) motor is ignited in the ordinary way and the rocket starts its ascent. Once this is completely used burning particles are blasted out of this motor and ignite the upper stage. When this motor ignites the booster falls away to the ground and the upper stage continues as an ordinary rocket. This process seems lengthy although happens in under 0.1 of a second.
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The boosters are usually held on to the rocket with couplers so they can easily fall off at separation. Another design tip to note is that on the booster tube above the motor vent holes can be cut. These are simply holes (3mm) in diameter. These are not essential but greatly improve your chances of successful separation. If vent holes are not used, the burning particles that travel up the body tube, to ignite the motor above, pressurize the air in between the motors causing the stages to separate before the upper motor has lit (causing the rocket to fall back to earth). This process is exactly what the ejection charge does. If you use vent holes however the pressure can escape out of the tube resulting in successful separation.
this makes them much more effective. You can have as many
stages as you like in your models although the reliability goes down
significantly the more stages you have. Another thing to register is that a four
stager will not out-perform a three stager because of the lift-off mass.
