The given diagram depicts the components of a hot air balloon and its mechanism of ascent. Overall, there are four main parts to a hot air balloon including the skirt, the basket, the burner, and the envelope. In addition, the circulation of air inside and outside the balloon enables it to fly.
The lowest part of a hot air balloon is the basket, which houses a propane cylinder to provide fuel for the burner suspended above it. The inverted teardrop-shaped envelope features a skirt used to attach the envelope to the basket with ropes. The parachute itself consists of multiple vertical gores. Each of these gores is made by sewing together multiple small horizontal strips of fabric, extending from the throat to the crown of the parachute. At the top of the envelope lies the parachute valve, with a self-sealing flap allowing hot air to escape at a controlled rate.
The operation of the hot air balloon depends on the circulation of air for ascent and descent. The burner flame, fueled by the propane-air mixture, heats the air inside the envelope. Since this hot air is lighter than the cool air outside, it lifts the parachute, making it buoyant. The balloon’s ascent and descent are controlled by opening the self-sealing flap at the crown of the envelope to allow hot air to escape at a predetermined rate.