Flying High: Water Rocket Telemetry

Abstract

Milligan Engineering utilizes water rockets at summer camps and for certain mechanical engineering classes to illustrate key principles of aerodynamics and get students excited about engineering. While the rockets perform admirably as a tool to drive interest and encourage further learning, there are two major pitfalls. The first is the lack of hard data available from launches, and the second is the lack of post-launch control. The current method of determining peak altitude consists of measuring the angle of the apotheosis (the highest point) of the launch from the roof of Emmanuel. This allows the manual calculation of the data using trigonometry. While acceptable for a rough estimate, this data is imprecise and limited in usefulness. Out-of-control launches also have the possibility to harm individuals or damage property. In order to solve these problems, a telemetry system has been devised. A pair of ESP32 microcontrollers are linked with a peer-to-peer network which allows for two-way communication. One of the ESP32 boards is placed inside the rocket along with an accelerometer and a barometric sensor, while the other ESP32 remains on the ground. The onboard ESP32 sends back the acceleration and altitude data, which is saved onto an SD card. This data link can also be used to deploy landing aids, such as a parachute, or recovery devices, such as a speaker. The data delivered by the telemetry system allows students to optimize their designs post-launch with brand-new information. Students can prepare for future launches by optimizing aerodynamics to reduce horizontal acceleration, adjusting the water load to balance initial mass and “burn time,” and varying nozzle diameter to change the thrust characteristics. This telemetry system provides students the ability to monitor rocket performance and learn how revisions made to the rocket can affect flight characteristics. This telemetry hardware provides the Engineering Department a powerful tool to teach iterative design and generate engineering enthusiasm.