Igniter Tip

by Warren Massey, LUNAR #007

Some times the old-fashioned way is just plain better. What am I referring to? It is the way the Estes igniters are put and retained in the black powder motors. The colored plastic motor plugs that come with all the Estes motors are a relatively new invention on the rocket scene. For a much longer time before they made their appearance we were using small balls of recovery wadding pressed in with the tip of a pencil/pen to do the job. And, in my opinion, it did the job better! Not only does the wadding ball hold the igniter more tightly against the black powder but it also eliminates any confusion about which plug should be used with which motor. And it's environmentally much more friendly to boot! You want to size the wadding ball so that it is just large enough to snugly hold the igniter in as it is pushed deep in behind the igniter within the throat of the nozzle. If the ball is too small, the igniter will not be held in tightly. If the ball is too big, you will not be able to push it (and the igniter ahead of it) tightly against the black powder. Between these two extremes there is a fair amount of latitude. While you're at it, make sure the two wires of the igniter "sit astride" the wadding ball like a cowboy sits on a horse. If, instead, you let the igniter sit "side-saddle" (along side) the wadding ball then there is a good chance you are going to have a short circuit between the two wires. This last bit of advice applies equally to the plastic motor plugs; it's just easier to do with the wadding ball.

Information date: September 14, 1997 lk