Make: High-Power Rockets

Chapter 7. Altimeters and Dual Deploy with Cable Cutters

Rockets that fly high have a problem. They need to touch down softly, to protect both the rocket and the things it might land on. At the same time, a moderate crosswind can easily carry the rocket as far away from the pad as the altitude it reached. That’s fine when it’s a model rocket that goes to 1,000 feet, but not so acceptable when it’s a high-power rocket that soars to 15,000 feet—about 3 miles!

This chapter shows the first way to solve the problem. The rocket pops the parachute at apogee, but the parachute is secured with a zip tie. The rocket falls quickly to about 500–1,000 feet, where a barometric pressure sensor fires a cable cutter that cuts the zip tie, allowing the parachute ...