What are balloons made of

How are hot air balloons made?

You would like to fly in one but have you ever wondered how hot air balloons are made?

Unlike most item you purchase hot air balloons aren’t assembled on a production line, each ballon is hand made by skilled craftspeople. The main parts of a hot air balloon are the envelope, the burner, and the basket.

The envelope - the pretty bit

The envelope is made from material that is both strong and lightweight. With nylon being the most commonly used fabric as it can withstand the heat and tension involved in a hot air balloon flight. The nylon is cut into panels and sewed together by skilled sewers. An individual panel is known as a gore, and a balloon can be made from four to 24 gores.

At the very top of the envelope you’ll find thing called a crown ring, a metal hoop about 300mm in diameter. The crown ring is attached to the envelope with tapes that take the load of flight.

At the top you’ll also find a vent that allows air escape on demand, making the balloon descend. The most common type of vent is known as a parachute vent. When a control lined is pulled, the vent opens. Releasing the line causes the hot air inside the balloon to close the vent.

Most recreational flight balloons have the typical tear drop shape, but these days envelopes can be made of any shape without significantly affecting its aerodynamic qualities. They may just take a lot longer to inflate and pack away. They can also be very heavy, unto 400kg.

The basket - not for washing

The basket needs to be strong and need to hold both the passengers and the pilot. The larger the balloon envelope the larger the basket, more passengers. Most baskets are made out of cane. Although some baskets are made from modern synthetic materials, but cane is still used as it is resilient, lightweight and easy to keep clean. That tradition look will never go out of fashion.

The burner - fire it up

The burner is powered by propane gas and heats the air inside the balloon that causes it to rise. Small balloons may only have a single burner but larger balloons will have up to 4. They use between 1 and 3 litre per minute and cooks a chook in about 45 seconds.

Instruments - where the hell am I?

Pilots must carry instruments to measure altitude, the rate of climb and air temperature. Radio’s to communicate with Air Traffic Control and ground crew. GPS is carried in the balloon to aid navigation and assist the ground crew can track the speed and direction of the balloon.

Maintenance - Is that hole supposed to be there?

Hot air balloons need to be kept clean and dry to prevent mildew and mould when packing. Like all registered aircraft they must be checked every 12 month for 100 hrs by a certified maintenance authority to ensure the aircraft is serviceable.

Clare Allen