BALLOON PRE-FLIGHT
A Typical Balloon Pre-Flight to Take-off
Many people ask us how balloons work and what’s involved. Here’s a picture story of a typical trip with the team. The pictures were taken during our preparation to be airborne
On arriving at the launch site we pick an area clear of other balloons and obstacles and unload the trailer. We need an area about30m x 30m to setup which can be difficult to get at a large balloon event.
Every balloon team has their own procedures. We load our trailer in a way that means unloading the first thing we need i.e. the basket and when packing up the basket is last to go in. This also helps keep the weight over the trailer axle.
After having been pulled out the envelop is spread out side ways. Only the reinforced load tapes are handled.
The envelope is packed in a bag in such a way that the bottom containing the mouth, the scoop and the cables, comes out first. The bag is placed about 5m up wind of the basket and in line with the general wind direction. This helps when inflating the balloon later on.
The envelope is pulled out of the bag in the direction of the wind.
After the equipment is unloaded we face the front of the basket upwind and assemble the balloon. The burner, which heats the air in the balloon, sits in a frame mounted on 4 plastic poles at each corner of the basket.
Once the balloon is upright, the pilot carries out a series of checks to confirm the rigging is in order.
To attach the basket to the burner and then the balloon envelope, there are eight steel wires which run under the basket. These attach to carabineers on each corner of the burner frame. These in effect take the entire load when the balloon lifts off
Carabiners connect the envelope to the basket wires and the burner frame. The carabiners are inserted starting from the short side of the burner frame.
The two fuel lines are fitted to the front two propane tanks. A third smaller line is used to provide fuel for a pilot light to ignite the propane as it leaves the burner. As the tanks empty in flight, the fuel lines are disconnected and moved to the back tanks. We try to land with the fuel lines attached to the back tanks for safety purposes.
For safety the burner has two duplicate fuel systems. These each incorporate a fuel line; a main valve and a low flow whisper valve. If a problem occurs with one fuel system or a tank change is required, there is always another independent fuel system. Of course if one of the systems fails we land as soon as possible.
To increase the burner efficiency, the propane is warmed as it first runs through a coil at the top of the burner which is heated by the flame.
Whilst the pilot connects the fuel system, another crew member fits covers to the burner mounting poles. This protects the fuel lines and wires from a hard landing and generally tidies things up.
The pilot light hose is connected to the propane tank.
The car and trailer are maneuvered behind the basket and are attached to the basket via a quick release harness. This prevents the balloon from drifting when inflated due to any light gusts of wind.
Note the blue quick release harness which is connected to the trailer.
The crew keep the envelope mouth open.
Whilst the envelope is like this, it is safe from the effects of the wind and will stay like this until the pilot is ready to inflate.
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.
The pilot then locates himself in front of the burner and puts short bursts of heat into the envelope. It is important to control the ascent of the envelope as too fast can cause under inflation causing the mouth to close. During this time the fan is still blowing air in to the envelope.
As the balloon raises the crew member on the crown line attempts to slow but not stop the ascent of the balloon to the vertical.
Almost ready to go!
The main burner flame is carefully directed up the center of the envelope.
The Pilot then completes the pre-flight checks; radio; GPS and ensures everything is secure. The large piece of heat resistant material attached to the frame is called the scoop. This helps to keep the balloon from spinning in the air by acting as a sail and also to direct the maximum amount of air up into the envelope to keep it inflated.
During this time the crew keeps their weight on the basket to stop it moving around.
When on the ground the burner is supported by nylon poles above the basket.
Everything on board check it’s clear to take off and its in Air
