• Overview
• Abstract
• Technical Specifications
• Test Results Gallery
• Versioning System
• Key Features
• Repository Contents
• Safety Considerations
• How to Use This Repository
• Citation
• Authors
• License

This repository documents the design, construction, and testing of a hybrid rocket engine demonstrator, developed as part of our Travail de maturité and presented at the Swiss National Contest.

Hybrid propulsion combines a liquid oxidizer with a solid fuel grain, offering a middle ground between:

• Simplicity and accessibility of solid rockets
• Performance and controllability of bi-liquid engines

Our objective:
👉 Build a reliable, efficient engine with limited resources, able to theoretically propel a model rocket.

Over 9 months, we applied an iterative engineering process:

• Design: CAD modeling (Fusion 360), rendering (Blender), combustion simulations (RocketCEA).
• Construction: Machined steel combustion chamber, graphite nozzle, ABS/ASA fuel grains.
• Instrumentation: Custom-built static test bench with Arduino-based data acquisition (thrust, pressure, temperature).
• Testing: 18 static firings, continuously improving injector design, nozzle geometry, and fuel formulation.

Results:

• Stable thrust plateau of 26 N (peak 40.4 N) during 5-second burns
• Combustion chamber pressure remained constant
• Temperature < 150 °C (no thermal risk observed)
• 16 out of 18 successful tests → high system reliability
• Supersonic exhaust confirmed (visible shock diamonds)

These results confirm that hybrid propulsion is a viable option for model rocketry, balancing performance, cost, and safety.

• Fuel Mass: 46g initial, 34g consumed (73.9% burn efficiency)
• O/F Ratio: 9.0:1 (oxygen to fuel)
• Operating Temperature: <150°C (safe thermal limits)
• Success Rate: 89% (16/18 successful tests)

• Version 1 Tests - Initial proof of concept
• Version 2 Tests - Improved injector design
• Version 3 Tests - Optimized nozzle geometry

Note: Each test folder contains detailed telemetry data (.TXT), analysis spreadsheets (.xlsx), temperature plots (.png), and test videos (.MOV)

All engine prototypes and test runs were indexed as:

VX-Y-Z

• X = Major version (nozzle/injector redesign, new chamber)
• Y = Minor variant (fuel grain geometry, material)
• Z = Test number of that configuration

Example: V3-1-2 → Engine Version 3, first minor variant, second test.

• 🔧 Custom static test stand
• 📈 Arduino Nano + sensors for thrust, chamber pressure, temperature
• ♻️ Iterative development cycle (SpaceX-inspired approach: "Test, Fail, Fix, Repeat")
• 🧪 Supersonic flow proven with visible shock diamonds

• 📊 NW25-643729_Finale_Arbeit.pdf → Full technical paper (108 pages with detailed methodology, results, and analysis)
• 📂 docs/shock_diamond.png → Supersonic exhaust visualization showing shock diamonds
• 📂 docs/v1/ → Version 1 test data (initial proof of concept)
• 📂 docs/v2/ → Version 2 test data (improved injector design)
• 📂 docs/v3/ → Version 3 test data (optimized performance)

Each test folder (docs/v{X}/v{X}-{Y}/v{X}-{Y}-{Z}/) contains:

• Raw telemetry: .TXT files with time-series sensor data
• Analysis: .xlsx spreadsheets with calculated performance metrics
• Visualizations: .png graphs showing thrust, pressure, and temperature
• Documentation: Test footage in .MOV format

⚠️ IMPORTANT SAFETY NOTICE ⚠️

This project involves high-pressure systems, combustible materials, and rocket propulsion. DO NOT attempt to replicate without proper safety training and supervision.

Safety measures implemented:

• Static test stand with blast shields
• Remote ignition and data acquisition
• Fire suppression equipment on-site
• Proper ventilation and outdoor testing
• Personal protective equipment (PPE)
• Emergency shutdown procedures

For educational use only - This documentation is provided for learning purposes. Always consult with professionals and follow local regulations before conducting any rocket engine testing.

1. Navigate to test folders: docs/v{version}/v{version}-{variant}/v{version}-{variant}-{test}
2. Key files in each test folder:
   • .TXT files: Raw sensor data (time, temperature, pressure, thrust)
   • .xlsx files: Processed data and analysis
   • .png files: Performance graphs and temperature plots
   • .MOV files: High-speed test footage
   • *-output.txt: Summary results and calculated performance metrics

• Thrust measurements in Newtons (N) and equivalent mass (kg)
• Chamber pressure in bar and Pascals
• Temperature monitoring at multiple points
• Burn time and total impulse calculations
• Fuel consumption and efficiency metrics

This work represents a comprehensive study of hybrid rocket propulsion suitable for:

• University-level aerospace engineering courses
• High school physics and chemistry demonstrations
• Research into hybrid propulsion systems
• Model rocketry safety and performance analysis

If you use this work in academic research or educational materials, please cite:

Bumann, S., & Gebhard, S. (2024). Hybrid Rocket Engine Demonstrator: 
Design, Construction, and Testing. Swiss National Contest - Travail de maturité. 
Gymnase de Morges. Retrieved from https://github.com/Bestsage/Hybrid-Rocket-Engine

Academic Paper: The complete 108-page technical documentation is available in NW25-643729_Finale_Arbeit.pdf

• Sacha Bumann
• Samuel Gebhard

With the support of:

• Gymnase de Morges
• dr. Ricardo Perez
• prof. Gabriel Paciotti
• Daniel Gebhard

This repository is provided for educational and research purposes.
Feel free to explore, learn, and build upon our work 🚀