Case M10 Stability Report
Preliminary FDM result: inertia, control derivatives, rate damping, and propulsion are placeholders; ADB v1.1 contains alpha-beta data only.
Database Metadata
- File:
adb_v1_1_drag_correction_m10.csv - Moment/reference/CG:
(-0.100, 0.000, 0.150) m - rho:
1.090 kg/m^3, q_ref:340.625 Pa, S:1.805 m^2, b:3.950 m, c:0.457 m
Trim
- success:
True - alpha:
1.7432 deg - theta:
1.7432 deg - elevator:
-1.8846 deg - throttle:
0.1608 - residual norm:
5.859e-14
Static Stability Derivatives
- Cm_alpha:
+0.446907 /rad(unstable longitudinal static sign) - Cn_beta:
+0.028648 /rad(stable directional static sign) - Cl_beta:
-0.010723 /rad(stable lateral static sign) - CL_alpha:
+4.858682 /rad - CY_beta:
-0.227790 /rad
Dynamic Modes
| Mode | Eigenvalues | wn rad/s | zeta | time constant s | Classification |
|---|---|---|---|---|---|
| phugoid | -0.32842+0.893381j; -0.32842-0.893381j | 0.9518 | 0.3450 | 3.0449 | stable |
| short_period | -9.31431+0j; +1.1421+0j | 1.1421 | -1.0000 | 0.8756 | unstable |
| dutch-roll-like lateral-directional | No clearly identifiable Dutch-roll-like lateral-directional oscillatory mode was found in this linearization. | n/a | n/a | n/a | not identified |
| roll | -30.2281+0j | 30.2281 | 1.0000 | 0.0331 | stable |
| spiral | +0.000287463+0j | 0.0003 | -1.0000 | 3478.7093 | unstable |
Summary
- Static stability: longitudinal
unstable, directionalstable, lateralstable. - Dynamic stability among identified reduced-order modes:
unstable. - Unstable modes: short_period, spiral.
- No clearly identifiable Dutch-roll-like lateral-directional oscillatory mode was found in this linearization. Because the aircraft uses an inverse V-tail/ruddervator layout and the current lateral reduced eigenspectrum is entirely real, treat this as a model limitation and classification ambiguity to investigate before flight-test use.
Conclusion
Case M10 improves the longitudinal trend relative to nominal but remains unsuitable as a stability baseline. The pitch static derivative is still unstable, the longitudinal dynamic response is unstable, and the spiral mode is weakly unstable in this linearization.