Rocket Water Ballast System
Description
I followed a complete engineering design process to create a functioning water ejection system for a high altitude rocket. This system ejects 2 kg of water in 90 seconds from a 6 in diameter rocket during the post-apogee descent. I was one of four payload engineers on the Experimental High Power Team. Aside from my payload responsibilities, I also helped with the overall creation, coordination, and launch of the rocket.
This was the first time BYU Rocketry launched with a hybrid motor - we made the news!
Key Takeaways
- Successfully launched and recovered BYU's first hybrid rocket and first water ballast system
- Competed in California's FAR-OUT 2025 competition
- Used a custom launch trailer designed by senior engineering students
Timeline
Duration: September 2024 - April 2025
Total time: 50 hours
Time commitment: 1-2 hours a week for 32 weeks
Result
Preparation & Design
In two technical design presentations (PDR and CDR) our rocket and payload designs were itteratively improved upon before construction began.
The Experimental High Power Team of 2024-2025
Overview of rocket internals
Design and anaylsis of rocket in OpenRocket
Our intial design had a container of water which was pressurized by a motor-plunger system, causing ejection of the contained water.
CAD model of water ejection system
Videos
Here are two videos from our successful test launch
Accomplishment
This was the first Utah student-made hybrid rocket launch and recovery and a news article was made about this.
Close-up view of launch
Rocket achieved apogee of ~6,000 ft
Final Product
The final design consisted of three parts when taken out of the rocket.
Complete water ballast system
Description of each component from left to right:
- Water bag - flexible, compact storage of up to 3 kg of water
- Top bulkhead fitted with a solenoid - allows for complete control of water valve
- Plunger and bottom bulkhead attached with motor, batter, and electronics
Essentially the water bag is sandwiched between the two bulkheads inside the rocket. The motor is activated during post-apogee descent by an altimeter and begins to extend the plunger. The plunger squeezes the bag and the water exits through the solenoid and tubing to leave the rocket.
Top view of water ballast system
I assisted in the production process of creating our carbon fiber rocket tubes. The following pictures depict the fully assembled and decorated rocket.
Rocket name: CATEGORY V
Technical Skills
Engineering Design
Learned how to pioneer a new system through iterative design and testing.
Manufacturing
Learned how to manufacture and fabricate various parts and components using various tools. Examples: custom parts with 3D printing, carbon fiber, crimping and soldering, use of lathes and mills, and more.