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Anatomy of a Hot-Air Balloon
The hot air balloon consists of three parts: envelope, basket, and burner system.
Balloons are categorized by the Federation Aeronautique Internationale (FAI), according to how much air their envelopes can contain.
Balloons are categorized by the Federation Aeronautique Internationale (FAI), according to how much air their envelopes can contain.
The Envelope
The part of the balloon that looks like a balloon is actually called an envelope. Some pilots also affectionately refer to it as "the bag." It is connected to the gondola, or basket, in which pilot and passengers ride, by means of stainless steel suspension cables.
The fabric in the envelope is rip stop, fire-resistant nylon, similar to material used in the backpacks or lightweight tents carried by hikers and mountaineers.It is woven in panels, two panels making up what is a gore.
The envelope is usually treated with a polyurethane coating to reduce porosity, and in the coating is an ultraviolet inhibitor to help the fabric withstand the rays of the sun.
The top cap or crown of the balloon may be designed in one of two ways. The standard top features a circular deflation port that is closed off by a circular panel, which is held sealed during flight by a flexible hook and-loop closure.
A deflation port line, usually called the rip line and colored red, extends from the top to the basket and is pulled by the pilot upon landing to effect an instantaneous deflation of the envelope. Pull on the line, and the hook-and-loop closure comes open, and the hot air rushes out.
The parachute top also features an opening in the crown, along with a similar circular panel to fill the opening. In this case, the panel is rigged up with lines, as the name suggests, exactly like a parachute. It is used both for effecting a complete deflation of the envelope afterlanding, and also during flight to vent a limited amount of hot air as a means for controlling vertical ascent or descent.
After landing in the parachute top balloon, the pilot pulls on the top line and holds it open for as long as he can until the envelope has been deflated. Balloons built with the standard deflation port also feature an opening in the side known as the maneuvering vent, also initially sealed, like the deflation port by hook-and-loop closure. This vent is operated by a rope called the maneuvering vent line, which extends from the vent to the basket. The pilot pulls the line, causing the side vent to open and allowing the hot air to escape to stop a rate of ascent or initiate a rate of descent. Once the line is released, the vent automatically recloses.
A skirt is connected to the bottom section of the envelope with peelable tabs and helps create a stovepipe effect when the burner system is running, channeling the warm air into the balloon and improving fuel efficiency, especially on windy days, by protecting the burner from the wind.
Attached to the inside of the balloon envelope, near the top or crown, are temperature indicators known as telltales. These telltales are white when installed but turn black if the air in the envelope exceeds a certain temperature. This permits the pilot to tell at a glance when his balloon may need repair.
The cubic capacity of an envelope dictates how many people can be carried aloft safely in a balloon. However, this capacity may be adjusted upward or downward depending on other factors, principally air temperature, altitude and what might be bluntly described as the Fatso Factor.The key is to determine the maximum safe gross weight that can be carried by the balloon on a given day.
The part of the balloon that looks like a balloon is actually called an envelope. Some pilots also affectionately refer to it as "the bag." It is connected to the gondola, or basket, in which pilot and passengers ride, by means of stainless steel suspension cables.
The fabric in the envelope is rip stop, fire-resistant nylon, similar to material used in the backpacks or lightweight tents carried by hikers and mountaineers.It is woven in panels, two panels making up what is a gore.
The envelope is usually treated with a polyurethane coating to reduce porosity, and in the coating is an ultraviolet inhibitor to help the fabric withstand the rays of the sun.
The top cap or crown of the balloon may be designed in one of two ways. The standard top features a circular deflation port that is closed off by a circular panel, which is held sealed during flight by a flexible hook and-loop closure.
A deflation port line, usually called the rip line and colored red, extends from the top to the basket and is pulled by the pilot upon landing to effect an instantaneous deflation of the envelope. Pull on the line, and the hook-and-loop closure comes open, and the hot air rushes out.
The parachute top also features an opening in the crown, along with a similar circular panel to fill the opening. In this case, the panel is rigged up with lines, as the name suggests, exactly like a parachute. It is used both for effecting a complete deflation of the envelope afterlanding, and also during flight to vent a limited amount of hot air as a means for controlling vertical ascent or descent.
After landing in the parachute top balloon, the pilot pulls on the top line and holds it open for as long as he can until the envelope has been deflated. Balloons built with the standard deflation port also feature an opening in the side known as the maneuvering vent, also initially sealed, like the deflation port by hook-and-loop closure. This vent is operated by a rope called the maneuvering vent line, which extends from the vent to the basket. The pilot pulls the line, causing the side vent to open and allowing the hot air to escape to stop a rate of ascent or initiate a rate of descent. Once the line is released, the vent automatically recloses.
A skirt is connected to the bottom section of the envelope with peelable tabs and helps create a stovepipe effect when the burner system is running, channeling the warm air into the balloon and improving fuel efficiency, especially on windy days, by protecting the burner from the wind.
Attached to the inside of the balloon envelope, near the top or crown, are temperature indicators known as telltales. These telltales are white when installed but turn black if the air in the envelope exceeds a certain temperature. This permits the pilot to tell at a glance when his balloon may need repair.
The cubic capacity of an envelope dictates how many people can be carried aloft safely in a balloon. However, this capacity may be adjusted upward or downward depending on other factors, principally air temperature, altitude and what might be bluntly described as the Fatso Factor.The key is to determine the maximum safe gross weight that can be carried by the balloon on a given day.