The starting point
The Hugin arrived with nothing — no drawings, no specs, no manual. Everything here started with a tape measure: the airframe was measured part by part and rebuilt as a digital aircraft, and every number since is tagged as measured, simulated, or assumed.
How it flies
The model predicts the real aircraft: a 16:1 best glide, stall at 9.8 m/s, and nearly two hours of flight at its best-endurance speed — cross-checked against a comparable production airframe. These curves are the aircraft's fingerprint; every decision below traces back to them.
Proving it stable
Stability was computed twice, with two independent aerodynamics codes — and they agree. Where they disagreed, the disagreement pointed at real missing physics, and measuring the actual tail boom retired an early stability scare entirely.
Finding the real bottleneck
The stock setup felt underpowered, and the obvious suspect was the 40 A speed controller. Joining propeller data, motor limits, and the drag model proved the motor itself was the ceiling — and a 49-combination sweep found a swap that buys 15% more flight time on the same battery.
A simulator that doesn't cheat
The 6-DOF simulator flies on estimated state, not perfect truth: a 9-state EKF works from noisy, biased virtual sensors in turbulence. It recovers injected gyro errors almost exactly and holds attitude to 0.2° — the mission barely notices the difference.
| Qty | Part |
|---|---|
| 1 | Twin-boom EPO airframe "Hugin" |
| 1 | Turnigy D3548/6 790 Kv outrunner |
| 3 | APC propellers |
| 6 | 5S 5000 mAh LiPo |
| 1 | 40 A ESC |
| 2 | APM 2.5 autopilot |
| 1 | Custom STM32H743 FMU (Rev B) |
The flight controller it earned
The program's findings became hardware requirements: a custom STM32H743 flight controller in KiCad — dual IMUs, CAN, SD logging, ArduPilot-ready. Spec written by the model, not guessed.
Appendix — Figures & Plots
6 figures · click to enlargeSupporting imagery for this project — boards, plots, screenshots and build shots that did not make the narrative above. Click any figure to open it full-screen.