About hot air balloons – The envelope

The main body of a hot air balloon is often referred to as the Balloon Envelope and is made from hundreds of different panels called gores. Although comprising of hundreds of gores, the balloon envelope has three distinct sections, the bottom or skirt, the middle, and the top which is also known as the Hyperlast.

The bottom of the envelope or skirt is the closest to the balloons burners and is made from a heat resistant fabric called Nomex. This fabric is the standard used in most hot air balloon envelopes and is flame and heat resistant. Nomex is also used in a range of high-temperature applications such as NASCAR racing and for firefighters clothing.

The biggest part of the envelope, which consists of the bottom two thirds, is made up of a combination of polyester and nylon. The fabric is tightly woven and is virtually air tight; this allows the balloon to fill with air to provide lift. Polyester and nylon are used because they are very light and durable and both have a high melting temperature, making it ideal for the envelopes structure.

The top third of the hot air balloon is called the Hyperlast and is made from a heavier nylon yarn. This makes the Hyperlast extremely strong. Added to this section is a special silicone coating that protects the balloon from mould and fungi growth.