Before the air can be heated the envelope needs to be inflated with cold air.
As we sometimes have inexperience crew, we like to get to this stage about 15 to 30mins from our intended launch time. This leaves plenty of time for briefing the retrieve crew and to look over maps etc. It also gives the pilot some time to get a feel for the local weather trends and maybe let off a weather balloon.
Before the inflation fan is started, the envelope cables and carabiner are doubled checked. The mouth of the balloon is then held open by two crew members. As can be seen because the balloon is in line with the general wind direction, it is already starting to inflate from the wind.
The fan is then switched on and in the same way as a party balloon is inflated air is blown into the envelope. This keeps the air in the envelope at a slightly higher pressure than outside allowing about 60% of the fabric to rise.
Whilst the balloon is inflating, the pilot secures the parachute. This is a large flap of material which seals an opening at the top of the balloon. The system allows the pilot to release hot air during flight by pulling on a rope which comes from the parachute all the way down to the basket. When pulled the parachute opens slightly allowing hot air to escape and is replaced by cooler air at the bottom, cooling the overall temperature inside the balloon. This is used in flight for rapid decent or on landing to quickly deflate the balloon.
Whilst inflating the balloon the parachute is attached by Velcro strips but in flight is held in place by the pressure of the hot air in the envelope.
After the inside of the balloon is checked, a crew member goes to the end of the crown line and holds the rope. When the pilot is ready to heat the air in the envelope he will indicate to the crown line to start pulling on the rope.