The Big Crayon

As mentioned last post, I got hold of some 36" tall crayon banks to further my adventures in rocketry. In fact, this design will take me squarely into the realm of mid and high power rocketry. Several rocketeers have built and flown these banks before, most notably Dr Sue down in Florida. She's taken the notion to extremes (not in a bad way, mind you, just wild!). And its her musings and build logs that inspired me to have a go at it as well. If you want to follow along and make your own, I'll pass a few measurements as I go. First up, the inner diameter of the tube (made of a strong rolled paper) is 3.76 inches the OD is 3.90 and the tail and nose cone pieces at their widest are 4.00.

I started with the engine mount, which is built around an Aerotech 29mm engine. I got a great deal on a reload shell, so my first flight will be with an RMS engine reload, an F-class motor. Here, I've made centering rings from 3mm lite ply I had lying around from Tokyu Hands in Shibuya. I then dry fitted them to the engine tube, a 30mm tube from Quest that fits the engine tube beautifully. Nothing is glued yet, because things will change. The lower set of rings will join with the fins and attach to the lower crayon shell.