Ever look up at the night sky and wonder what's out there? If so, you're not alone. For thousands of years, humans have been fascinated with what lies beyond our planet.
In 1926, Robert Goddard launched the first liquid propellant rocket and since then, the global scientific community has accomplished amazing things in space exploration. Because of this, today, even hobbyists can pursue their interests in rocketry.
Our friend Tanish has a growing interest in rocketry, and he reached out to @CO and me to help him design, make, and launch a custom rocket. He wants to gain skills that will prepare him to compete in the American Rocketry Challenge.
Chinloo and I are both Mechanical Engineers, so we have a firm foundation in physics, we understand the principles of flight, and are competent in mechanical design, but neither of us are experts in rocketry.
Thankfully, there's a free program, called OpenRocket, that will help guide you towards designing a good rocket. You can input all sorts of values, from the size of the nose cone, body tubes, and motor (engine), to the shape and number of fins, to the weight and location of your payload.
What it reveals is the location of the rocket's center of mass (the point where you can balance it on one finger) and its center of pressure (the point where all of the aerodynamic forces are balanced). In general, you want the center of mass in front of the center of pressure and ideally, the distance between the two should be between 1 and 2 times the diameter of the rocket. Achieving this ratio is the key to a rocket's stability.
This year's challenge is to build a model rocket that carries a chicken egg to an altitude of between 800 and 850 feet, stays airborne for between 43 and 46 seconds, and returns the rocket to the ground safely with an unbroken egg
Once Tanish worked things out in OpenRocket, he started modeling all of the rocket pieces in SOLIDWORKS. The body tubes would be purchased cardboard parts, but all the other parts would be 3D printed.
Figuring out a way to hold the egg and the motor in place was a fun challenge. We came up with a cradle for the egg that has three tabs on it which fit inside the nose cone and then twist to lock it in place. We designed a sleeve and used the same twisting concept to hold the motor in place.
Tanish assembled and painted all of the parts, crowning his creation "The Eggcubator"!
Launch day was amazing! There were a few moments where we thought we weren't going to be able to launch, but in the end we all had the joy of seeing the rocket blast off into the sky, and we all learned a few really important lessons about rocket design.
Check out the full video to see how the project came together, what challenges we faced on launch day, and the lessons we learned that will help Tanish improve his rocket design in the future.
