MMX BIC Pencil

While half-listening through an afternoon of telecons a while ago I realized the eraser end of a used-up BIC mechanical pencil fit an MMX motor just about perfectly, so I converted it into this little oddroc:

The pencil came apart easily just below the eraser & clip segment, which had previously served as the button to ratchet forward the graphite. With the guts removed, design and construction was clear sailing.

A bit overkill, but first I weighed the body segments and whipped up a very rough simulation in OpenRocket to reduce the guesswork on how big to make the fins:

The fins were then cut from some discarded blister packaging. I took a risk and used superglue to attach them. Unfortunately they fogged up as half expected, but still looked reasonable.

Probably unnecessary versus just shoving in a motor, but I peeled a layer or two off a T-MM tube to put it into the eraser/clip segment as an insulator, and to visually replicate the now removed white rubber eraser.

To secure the shock cord in the front section I sanded down a small dowel and drilled a hole in it. After running the shock cord through the hole and tieing a bulky stopper knot, I put some glue deep into the front body segment and pushed the dowel piece into it. At the back there wasn’t space to affix the shock cord inside without likely blocking the ejection charge. So I used kind of a variation on a minimum diameter technique, running the shock cord all the way out the back. The motor tube then squeezed in next to it and was glued in place, with another bulky stopper knot securing the shock cord just out of the way of inserting a motor.

A launch lug & streamer and the build was complete, a fun afternoon mini-project.

Today I finally got around to launching the little guy. Unfortunately, despite landing close by, this oddroc took its one and only flight to glory, as it was lost forever among the snow and corn husk remnants. But the flight was great, a clean arc and good altitude, and I’m very pleased with how this BIC-roc turned out.

I also greatly enjoy the juxtaposition in the launch video of the quite substantial scratchbuild on the rack alongside this tiny micro-rocket that’s too small to even be easily discernible on its pad.