Ballonghöljet

Ballonghöljet is the outer fabric enclosure of a buoyant balloon, most commonly referring to the envelope of hot air and gas balloons. It serves as the large gas- or air-tight bag that contains the lifting medium and defines the balloon’s shape.

Construction and materials are typically lightweight, durable fabrics such as ripstop nylon or polyester, often with protective coatings to reduce gas permeability, UV degradation, and wear. The envelope is assembled from multiple gores—panel sections sewn together—to create a smooth, rounded shape. It includes a fill neck or throat for inflow of air or gas and a valve or closure mechanism to regulate filling and venting. In hot air balloons, a top vent or controlled openings allow rapid release of heated air to descend, while gas balloons rely on venting of lifting gas to adjust altitude.

Function and operation revolve around buoyancy. For hot air balloons, a burner heats the air inside the envelope, decreasing its density relative to the surrounding atmosphere and producing lift. For gas balloons, lighter-than-air gases such as helium or hydrogen provide the lifting force, with the envelope’s shape and fabric preventing gas leakage.

History and development trace the envelope back to the early balloon experiments of the 1780s, with material innovations advancing from silk and cotton to modern synthetic fabrics. Maintenance emphasizes regular inspection for fabric wear, seam integrity, and leaks, with repairs and overhauls ensuring safety and performance.