Which balloon type combines a gas cell with a heated-air chamber?

A Rozière balloon combines a gas cell with a heated-air chamber.

The design is named after French aeronaut Jean-François Pilâtre de Rozier. Unlike a Montgolfière, which relies only on heated air, a Rozière uses two sources of lift. A sealed cell contains a lifting gas such as helium, while a separate lower chamber contains air heated by a burner.

This hybrid arrangement can improve endurance because the pilot can control altitude without continually dropping ballast or relying entirely on burner operation. It is especially useful for long-distance flights, where efficient management of lift is essential.

The term is often confused with Charlière, the name for a hydrogen balloon, and Montgolfière, the name for a hot-air balloon. A Rozière is neither a simple gas balloon nor a simple hot-air balloon. Its defining feature is the combination of both systems in one craft.