A Bit Of History
Balloons have evolved at quite a rate since their introduction over 200 years ago. In 1783, in France, Pilatre de Rozier and Marquis d'Arlandes flew in a balloon manufactured by the Montgolfier brothers. The envelope was made of paper and the heat was gained by burning straw in the centre of a large basket. The balloon was tied to the ground until enough heat was generated to lift the balloon. The ropes were then cut and the balloon flew until it cooled down once more.
Just 10 days later, Professor Jacques Charles launched the first gas balloon. The balloon consisted of a silk envelope that was filled with hydrogen. Since hydrogen is lighter than air, the balloon rose.
All of this took place some 120 years before the Wright brothers first flight!
The Modern Hot Air Balloon
Ballooning went through a very quiet period up until the late 1960's/early 1970's with the advent of propane-powered burners. The pictures below are of one of our passenger rides balloons. The Hot Air Balloon is made up of three major constituent items:
The Basket - this is still manufactured in wicker. There have been countless efforts to find a modern-day substitute to no avail. There appears to be no suitable material that offers the same level of strength, resilience and durability!
Baskets are manufactured in a number of different sizes, ranging from a small basket that carries one person up to a double-decker (yes!) basket that could carry up to 50 passengers. Typically, the baskets used for passenger carrying would hold 10 to 16 passenges in small compartments, perhaps 2 to 4 per compartment. These compartments contain rope handles and are padded for maximum comfort. The pilot, together with the fuel tanks, would be contained in a further compartment.
The Burner - the burner draws fuel from the on-board propane tanks as liquid (the propane tanks contain liquid propane under pressure). This liquid then passes through a vapourising coil that is heated up in the burner flame. The resulting vapour is then ignited and used to heat the balloon. A single balloon burner would typically be rated at 20 *million* BTU's. Most passenger balloons would have between 2 to 4 separate burners on board. Each 60/80 litre propane tank normally lasts for about 20 minutes flying.
The burners also have a vapourising bypass, typically called a whisper burner, that burns liquid rather than vapour. This burner is less efficient but is much quieter in operation. This burner, therefore, is more suitable where there are any livestock in the area. It also burns with a much more yellow flame and is therefore used for the spectacular 'night glows' that can be seen at a number of ballooning events
The Envelope - the envelope is probably the most important and noticeable element of the balloon. The envelope is manufactured from coated rip-stop nylon. This coating helps preserve the fabric as the internal temperature of the envelope is 100 degrees Centigrade during flight! The passenger and basket load is supported by a number of vertical and horizontal load tapes that run up and across the balloon. These tapes are connected to the basket by wires. The fabric between the vertical load tapes is referred to as the 'gores'.
Again, envelopes are available in a variety of shapes and sizes. Passenger balloons are always of the conventional shape ( the special shape balloons are not allowed to carry fare-paying passengers ). A typical sporting balloon would be of a volume of around 77,000 cu ft and would carry up to 4 people. Most passenger balloons are between 180,000 and 315,000 cu ft. Even these may seem insignificant against the 'Pacific Flyer', flown by Per Lindstrand and Richard Branson across the Pacific. This balloon was 2,500,000 cu ft in volume!
The height of the balloon is controlled by raising or lowering the temperature inside the envelope. Anticipation is always the pilots keenest sense, as the application of the burner does nothing for between 10 to 20 seconds! The top of the envelope has a 'parachute' fitted that fits across a large opening. This parachute is pulled down after landing to let the hot air escape. These envelopes also have 'rotation vents' in the side that can be opened to rotate the balloon in a clockwise or counter-clockwise direction.