Most pilots don’t deliberately kill their balloons, but many have worked at shortening the useful life of their aircraft. The examples provided in this article are based on actual balloons brought into repair stations, or observed at launch sites. I am providing these examples so others may avoid such damaging behavior. In most cases, the damage may be prevented by avoiding the damaging behavior in the examples. I will also point out other ways to avoid killing your balloon.
Store the balloon improperly.
Improper storage is an excellent way to kill a balloon. Storing an envelope directly on a concrete floor allows moisture to wick through the bag and into the bottom layers of the fabric. Storing it outside can allow rain to soak the envelope. Moisture can cause any of several problems. The most common are mold and mildew. Mildew causes spots to form on the envelope, and causes a foul smell when you open the bag. Penicillin mold eats the polyurethane coating, causing porosity. Penicillin mold rot will typically cause the fabric to become porous all over the envelope. A whitish powdery residue is also evidence of penicillin mold rot. Moisture can cause the coating to delaminate from the fabric, usually in patches. You should store the envelope on a pallet to allow air to circulate under and around it. The pallet should be in a cool, dry area sheltered from wind and rain. If you store the envelope in a small enclosed area, use low power heating elements such as those designed to dehumidify closets.
Some pilots have chosen what they thought was a good way to store a balloon - use an enclosed trailer. One manufacturer reported replacing a low hour envelope under warranty because it failed its annual inspection. The replacement envelope later suffered the same fate. Further investigation found that the balloon was stored in a black trailer with no ventilation, and that temperatures exceeded 150 degrees F. on a regular basis. The trailer was stored in a midwestern state.
High temperatures can also cause your fuel tanks to vent propane through their pressure relief valves. If you have an enclosed trailer, a white roof and some form of ventilation will help keep it cool. Parking it in a carport or a shaded storage area will keep it even cooler.
If you live in a hot, humid area, consider storing your envelope in a temperature controlled storage facility while you are not flying.
Overload or overheat your envelope.
Flying your envelope with a full load on a hot day can cause the envelope to exceed the red line temperature. If you are flying in an area subject to temperature inversions, you will experience an increasing temperature as you climb. You may find you don’t have enough excess lift to penetrate the inversion layer while maintaining a reasonable envelope temperature. Extended operation at or above the specified maximum envelope temperature can speed deterioration of the envelope coating.
A “splash and dash” into fast moving water is another way to overload your envelope. The friction of the moving water can pull the basket into the water deeper than the pilot intended to go. Once the basket fills with water, it becomes extremely heavy. If you are able to fly out of this situation, you can expect to severely overheat the envelope. Otherwise you may need the help of emergency services to get you out of the water.
Soak your envelope.
Flying in the rain can cause the envelope to become extremely heavy. The extra weight can require high temperatures to stay aloft until you are over a suitable landing spot. You are then left with a very heavy wet envelope to dry out. If your landing spot is covered with dew or water from sprinklers or other sources, you will also have a damp envelope. Deflating the envelope onto a large tarp or plastic sheet can prevent the envelope from becoming wet.
If your envelope has become wet, it is important to dry it as soon as possible. There are several ways to dry it. If you have room in a garage or family room, you can spread the envelope out as much as space permits. Every hour or two, roll the envelope to expose more wet fabric, until it has completely dried. If the weather has changed, and outside conditions permit, perform an extended cold inflation until the fabric is mostly dry. Once enough moisture has evaporated to reduce the weight, stand the balloon up gently, keeping the temperature below boiling (212 F, or 100 C.). Heating damp fabric too much can generate steam between the coating and the fabric, causing the coating to separate from the fabric.
Fill your envelope with flammable vegetation.
Inflating a balloon in a field full of loose straw or grass can be hazardous to the balloon in more than one way. During the cold inflation, the inflator fan blows straw into the envelope. When the balloon stands up, the straw rains down inside the envelope. If you operate the burner while the straw is falling, you will ignite the straw. Some of the burning straw will rise in the hot air column and burn pinholes in the fabric. Some of it may also fall out of the envelope onto the ground, possibly setting the dry ground cover on fire. A tarp, carpet, or ground cloth spread from behind the fan to the mouth of the envelope can prevent the problem.
Yank hard on the parachute valve.
If your parachute valve was pulled down into the envelope during deflation, it is possible that the bridle lines or deflation line may be caught in the fabric. If you meet any resistance while pulling on the valve, have someone walk under the envelope to spread it out. Attempting to pull the bridle or vent lines through the fabric can cause abrasion damage or 3-corner tears. The vent line pulley in some balloons is also a catch point that can result in fabric damage.
Drag your envelope bag.
Many pilots and crews drag the envelope bag over rocks, sticks, parking lots, and sharp pieces of metal, tearing holes in the bag. The holes allow the envelope fabric to stick out. We have seen holes and tears through several layers of fabric caused by dragging the bag. If you find holes in the bag, repair them immediately and check for holes in the envelope.
Part two of How to Kill a Balloon will appear in a future issue of Balloon Life.