I picked up a bunch of rocket motors two years ago, but unfortunately my model rocket got lost during a winter launch last year. When a coworker asked me to do a rocket launch with a second-grade class, I knew I would need to improvise.
The motors are B8-3s, which means they have a decent kick for their small size. I rolled some paper around couple motors to make a body, then made the cone (roll up a half-circle) and glued on some fins and a little tube for the rod of my launch pad. A small square of paper towel serves as wadding, and a strip of shopping bag will slow the descent after the ejection charge pops off the nosecone.
The fuses don’t fit very well, so I get plenty of misfires. On my second attempt, the rocket launched. The nosecone fell off and the rocket’s launch was unsteady, but otherwise uneventful. I wasn’t able to retrieve the body to see what sort of damage it sustained.
The major flaw with this design is the instability of weight distribution. The center of mass — essentially the motor — is too far down the tube, which means a small wobble gets amplified because the nose wobbles more than the bottom. I will attempt to fix this by adding a small amount of mass to the nose.