Once upon a time my class at school got into model rocketry. The younger students made “tumblers” – small, light rockets that had no parachute and tumbled safely to the ground (in theory). Us sixth graders? We got to make REAL model rockets, with big ol’ engines and parachutes to bring the model back to earth safely.
Let me tell you how a model rocket engine works. They are cylinders that are lit from below using remote-controlled igniters. There’s a line of rocket fuel inside the engine leading up to the to top that propels the rocket upwards; at the top of the rocket is a surprisingly strong gunpowder charge. Its job is to pop the top of the rocket off so that the parachute can deploy and the rocket can waft safely to the ground.
So one day our instructor takes us out to the fair grounds so we can safely launch our rockets. Kid after kid lines up to try his rocket. All kinds of things are happening – igniters turn out to be duds, rockets turn out to be too heavy for the engines they are using and just sit on the launch pad blasting out sparks, tops don’t pop off when they’re supposed to so parachutes don’t deploy, etc.
Then, it’s my turn. My rocket launches, the parachute deploys and it drifts back to earth to be recovered. I am quite pleased. My instructor called it a perfect launch.
Finally, when all the students are done, the instructor brings out a rocket he’d been working on for a while. It’s painted. It’s got strange-looking fins that he designed himself. He says he’s finally going to test-launch it for us.
He puts a rather strong engine in it, puts it on the launch pad and presses the button.
The rocket flies straight up into the air for about thirty feet, makes a U-turn and comes straight back down, impaling itself in the soft earth of the fairgrounds and sticking straight up into the air.
We all start running towards it, disregarding our instructor’s calls that the rocket engine is still burning.
When we get about halfway to it, the gunpowder charge that would deploy the parachute goes off. But because the rocket is stuck up to its neck in the ground, there’s nowhere for the blast of that charge to go.
The rocket exploded into pieces, and we exploded into fits of laughter.