nTop 6-DOF Flight Dynamics Framework

A production-ready Python framework for 6-degree-of-freedom (6-DOF) flight dynamics simulation, integrated with AVL (Athena Vortex Lattice) and XFOIL for aerodynamic analysis of nTop-designed aircraft.

Project Status

✅ ALL CORE PHASES COMPLETE - Production-ready framework with 164 passing tests

For detailed phase-by-phase status, see Plan/status.md

Key Achievements:

• ✅ Complete 6-DOF dynamics with quaternion attitude
• ✅ Flying wing configuration with stable controlled flight
• ✅ FJ-44 turbofan integration with trim solver
• ✅ Triple-loop cascaded autopilot with stall protection
• ✅ Comprehensive testing (164 tests, all passing)
• ✅ Extensive documentation (1,100+ lines)

Recent Updates:

• Enhanced autopilot for flying wing stability
• Comprehensive user and tuning guides
• Full unit test coverage for autopilot controllers
• Performance benchmarks and validation

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Quick Start

1. Install Dependencies

pip install -r requirements.txt

2. Run Flying Wing Demo (Recommended)

python examples/flyingwing_stable_flight.py

Demonstrates the enhanced triple-loop cascaded autopilot achieving stable controlled flight.

3. Run Tests

pytest tests/ -v

All 164 tests should pass ✅

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Documentation

User Guides

• FLYING_WING_AUTOPILOT_GUIDE.md - Complete user guide (500+ lines)
• AUTOPILOT_TUNING_GUIDE.md - Practical tuning guide (600+ lines)

Technical Documentation

• Plan/status.md - Detailed project status
• TRIM_STATUS.md - Trim analysis
• RK4_AUTOPILOT_RESULTS.md - Integration testing

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Examples

Example	Description
flyingwing_stable_flight.py	Flying wing with enhanced autopilot (recommended)
simple_6dof_sim.py	Basic 6-DOF simulation
autopilot_demo.py	Altitude/heading/airspeed hold
stability_analysis_demo.py	Linearization and mode analysis
config_demo.py	YAML configuration system
visualization_demo.py	3D plots and animations

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Aircraft Configuration

Wing Geometry (from nTop)

Parameter	Value
Span	19.89 ft
Area	199.94 ft²
MAC	26.69 ft
Aspect Ratio	1.98
LE Sweep	56.64°
Taper Ratio	0.009

Mass Properties

Parameter	Value
Mass	234.8 slugs (7,555.6 lbm)
CG	(12.92, 0.00, 0.05) ft
Ixx, Iyy, Izz	14,908 / 2,318 / 17,227 slug·ft²

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Testing

Total: 164 passing tests ✅

• Phase 1 (AVL Geometry): 11 tests
• Phase 2 (6-DOF Dynamics): 23 tests
• Phase 3 (Supporting Systems): 22 tests
• Phase 4 (Analysis Tools): 11 tests
• Phase 5 (I/O & Configuration): 17 tests
• Phase 6 (Visualization): 19 tests
• Core Coverage: 29 tests
• Autopilot Controllers: 32 tests

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Directory Structure

nTop6DOF/
├── src/               # Core framework
│   ├── core/          # 6-DOF dynamics, quaternions, integrators
│   ├── environment/   # Standard atmosphere
│   ├── control/       # Autopilot and trim solvers
│   ├── analysis/      # Stability and frequency analysis
│   ├── aero/          # AVL interface and database
│   ├── io/            # Configuration and parsers
│   ├── visualization/ # Plotting and animation
│   └── simulation/    # Enhanced trim solvers
├── tests/             # Comprehensive test suite (164 tests)
├── examples/          # Demonstration scripts
├── config/            # YAML configuration files
├── Data/              # nTop exports (LE/TE points, mass)
├── Plan/              # Project planning and status
└── avl_files/         # Generated AVL files

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References

• AVL Website: http://web.mit.edu/drela/Public/web/avl/
• Project Plan: Plan/flight_6dof_project_plan.md
• Project Status: Plan/status.md

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License

MIT License - Copyright (c) 2025 Brad Rothenberg

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Last Updated: 2025-11-10
Version: 0.6.0-alpha
Test Coverage: 164 passing tests ✅