Clustering, like multi-staging, opens up a whole new area of model rocketry when you start it. Cluster models have more power so you are able to get faster acceleration. They are also useful for lifting heavy rockets off the launch pad. Unlike multi-staged models you do not get a longer flight time just a higher thrust because you have multiple motors burning instead of one. ie. Your model will travel faster as opposed to longer.

Cluster models are ones that have two or more engines that are ignited simultaneously. Providing the model with more thrust. Each of the motors has their own motor mount, clip and thrust ring. All of the motor mounts are held in place with a centering ring. Note : This obviously has to have multiple holes in it! You then simply put the motors in the motor mounts, all motors must be of the same grade ie. two "A8-3's" or two "B6-4's". If you use different motors the rocket will have more thrust on one side than the other and it will probably drive into the ground. 

The hardest thing about cluster rockets is igniting them. This is because all motors must be ignited before the rocket leaves the pad. The most common way of igniting a cluster is with the use of a 'clip whip'. For example, let's say you had a cluster rocket with three motors. You would have three red leads each connected to a clip and three black leads each connected to a clip. Then you bunch the blacks together and bunch the reds together so you have two connections, this is where your ordinary clips go. Finally you connect one black clip to each igniter and one red clip to each igniter. Note : To launch cluster models you will need a 12v launch system because of the extra power required to ignite several igniters.

To light multiple motors at once, such as in a cluster, you need a "clip whip." You can make clip-whips for two, three, or four motors, more if you dare.

For each ignitor, you will need:

• 2 copper micro-clips (with flat jaws; they grip ignitors better than alligator clips); Radio Shack sells these in packets.
• A length of 20 or 22 gauge 2-conductor speaker wire. I use the kind with one copper and one nickel lead in clear plastic insulation.  The exact length is not important, 10-18" is good;  all whips in a set should be about equal. Because this is a small gauge of wire, excessive length is excessive resistance.
• Solder.

Split each end of each lead about 2" at each end, and strip about 1/2" of insulation off every wire end. Refer to the illustration above.  Crimp and solder a pair of micro-clips on one end of each set.  Then gather all the loose copper ends; twist and solder together.  Do the same with all the loose nickel ends.

Using Them
On the pad, hook a pair of micro-clips to each igniter.  (If there are more leads than ignitors, such as if you are firing a two-engine cluster with a three-lead clip whip, just make sure the extra set does not short out.)  Hook your regular launch system clips to the free twisted, soldered ends.  Countdown and launch.