Warbirdlovers on Instagram: "Warbird Wednesday with this Boeing Stearmen firing into life with an inertia starter. An inertia starter operates by spinning a flywheel to store kinetic energy, which is then transferred to the engine. This transfer typically occurs through a reduction gear train and a clutch mechanism designed to prevent over‑torque. Historically, three types of drive systems have been used to accelerate the flywheel: manual (hand‑cranked), electric motor–driven, and hybrid systems