Category Archives: rockets

Tall One

Posted on by tjkopena

Finished and flew this ASP Tall Boy, rechristened Tall One, this weekend:

This is a real fun rocket. Straightforward to build, it’s made up of multi-segment balsa fins and four BT60 tubes. I think it looks good even with just one body segment, but at the full length it’s certainly an eye catcher. At 122.5″ it’s just a bit taller than my ground crew would be standing on my shoulders, which excited them greatly.

We used E30-4s for our two launches yesterday, captured in the video. That’s at the upper range of the recommended motors, but it gave the rocket a real jump off the pad and very clean, straight flights.

The graphics on our build are all custom cut vinyl. The rainbow is made up of six sine waves calculated to wrap around the tube. The paint is just Rustoleum spray primer, but I went through several layers of sanding, several for color, and one for clear coating to get it pretty smooth & solid. I was pleased that the balsa nosecone was mistaken for plastic by a person or two, rewarding the several layers of sealing & sanding before even getting to the paint layers.

Another interesting minor note in construction is an experiment w/ fillets. I used wood glue throughout and to form the fin and lug fillets as well, though I would normally use epoxy for the latter. Unsurprisingly the fillets developed some small air holes, which could maybe be just a bit tricky to fill w/ more wood glue, given that it shrinks. Instead these holes were easily and immediately filled using Bondic UV-cured resin.

My biggest suggestion for the kit is that a rocket this tall can really stand having the included launch lugs replaced with rail buttons. We were fortunate to have no wind today so we got two clean flights, but I’d worry about the rocket waving on the rod in more typical conditions. The included mylar parachutes are also a bit weak and could stand being replaced. On our first launch all the stickers simply tore off one of them, but fortunately the second chute was more than enough to induce a graceful float down. Otherwise, as I expect of ASP, the components are great and instructions clear. It’s a non-challenging but fun build process with just a couple interesting design choices and methods, resulting in a great flyer.

MMX BIC Pencil

Posted on by tjkopena

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.

ASP Aerobee 100 JR Followup

Posted on by tjkopena

Update on my ASP Aerobee 100 JR build that I’ve flown this model on G78s and G79s several times now. Great flights all. Notably, our last two section launches had no wind and the altitudes hit were spot on the estimates from the instructions: 3200ft on G78, 3040 on G79. At a prior launch in serious wind it did 2500ft on a G78. So I think just basic, everyday wind explains the discrepancies I’d been seeing from ASP’s projections.

This launch video is neat in that you can see the pressure build up and release.