A compound balloon is a lighter-than-air craft that combines a cell of unheated lifting gas, like helium or hydrogen, with a separate envelope of heated air. The pilot controls altitude by adjusting the temperature of the hot air section, preserving the expensive unheated gas for long-duration flight. This hybrid design provides the endurance of a gas balloon with the precise altitude control of a hot air balloon.
Heard on the job
We'll need the compound balloon for the transcontinental attempt to avoid dumping helium every time the sun goes down.
Also heard as
- Rozière balloon