Leonardo da Vinci designed a chimney jack, a heat-powered machine for automatically turning a roasting spit.
A chimney jack uses rising hot air from a fire to rotate a small turbine or fan. Gears then transfer that rotation to the spit, so meat turns without a cook having to operate a handle continuously. Leonardo’s drawings show this principle in a kitchen setting.
The design belongs to the history of early heat engines, although it did not produce useful steam power in the modern industrial sense. Its motion came from the upward flow of heated air through the chimney.
The chimney jack is sometimes mistaken for a wind-powered kitchen device. The key distinction is its energy source: hot air from the fire, not outdoor wind. Leonardo studied both airflow and mechanical gearing extensively.