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SETBACK 27 June 2026
The battery sings at ~15.8 Hz.
840 grams hanging that go into resonance with the structure. Rigid rebuild, the frequency shifts, but the fight goes on.
battery mass 840 g at rest 15-19 Hz → ~21 Hz (rigid rebuild) in flight ~15.8 Hz status fight in progress
The battery’s mass — 840 grams, the heaviest part — excites a mode of the structure. In a hover, everything starts to sing, and the altitude estimate suffers for it.
Rigid rebuild: the resonance moves from 15-19 Hz to about 21 Hz at rest, and the roll settles under target. But in flight, the structure stiffens and the mode climbs back toward ~15.8 Hz.
It’s the kind of problem you won’t find in any tutorial and that eats weeks. So we document it: the measurements, the decoupling hypotheses, and what we try on each run.