After buildin' a ground-up simulation o' t' vehicle's behavior under thrust, I re-tuned t' stability algorithm t' t' inertia I calculated from t' results o' a bifilar pendulum test. T' calculation be incorrect, arrr, due t' an extra set o' parentheses used, ya bilge rat, and t' algorithm was then tuned t' t' incorrect vehicle inertia. Avast, me proud beauty! T' calculated inertia was much smaller than it should have been, so t' simulation predicted a vehicle requirin' less control authority, hence t' loose oscillation durin' t' test. T' error be found soon after. For more info: https://twitter.com/joebarnard http://www.bps.space