Hot-Air Balloons: The First Flights, Striped Envelopes, and How to Color Them

A round envelope, bold stripes, a tiny basket underneath: a hot-air balloon looks as good in a drawing as in the sky, and the shape has a long history. This guide covers the first flights in 1783, the simple physics of lift, why so many envelopes are striped, and how to color the hot-air balloons theme on daubday.

Two paper makers from Annonay

The story begins with Joseph-Michel and Jacques-Étienne Montgolfier, brothers from a family of paper manufacturers in Annonay, in southern France. They found that light bags held over a fire would rise, without fully understanding why: Joseph believed the smoke contained a special lifting gas, when in fact the heated air was doing the work.

In June 1783 the brothers publicly launched an uncrewed balloon of paper-lined cloth in Annonay. That September they flew one at the palace of Versailles before King Louis XVI and Marie Antoinette, with a sheep, a duck, and a rooster as passengers. All three landed safely.

After tethered test ascents in October, Jean-François Pilâtre de Rozier and the marquis d'Arlandes made the first free flight with a crew on 21 November 1783. They rose from the Château de la Muette on the western edge of Paris and drifted over the city for about 25 minutes before landing outside the walls. The balloon carried its fire along, and the crew had to dab out embers scorching the fabric with sponges. It was a decorated object, too: the wallpaper maker Jean-Baptiste Réveillon gave it a deep blue background with gold suns and signs of the zodiac.

Less than two weeks later, Jacques Charles rose from Paris in a balloon filled with hydrogen, the first crewed flight of a gas balloon. Today's hot-air balloon, with a propane burner above the basket, was developed in the United States from the 1950s, notably by Ed Yost.

Why hot air lifts a balloon

The principle is the one that floats a cork. Heated air expands, so the hot air inside an envelope weighs less than the same volume of cooler air outside. When the upward push of the surrounding air exceeds the weight of the whole craft and its passengers, the balloon rises.

The difference per cubic meter is small, which is why balloons are so big. It also explains a few basics:

• Burner on, balloon up. Heating the air increases lift.
• Cooling brings it down. Letting the air cool, or opening a vent at the top to release hot air, starts a descent.
• Cool days help. On a warm day the temperature gap is smaller, so the balloon lifts less.
• No steering wheel. Pilots change direction by climbing or descending into wind that blows another way.

Gores: why so many balloons wear stripes

A modern envelope's fabric, usually ripstop nylon or polyester, is cut into panels and sewn into long vertical sections called gores, which run from the opening at the bottom, the throat, to the crown at the top. An envelope may have as few as four gores or more than twenty, and the fabric nearest the burner is fire-resistant.

Because each gore is cut separately, the simplest decoration is to give neighboring gores different colors. Alternate two colors and you get the classic striped balloon. Gores are widest around the middle and narrow toward each end, like the segments of a peeled orange, so real stripes curve and meet at the crown. Below hangs a basket, commonly woven from wicker or rattan, light yet strong enough for a firm landing.

Balloon festivals today

The Albuquerque International Balloon Fiesta in New Mexico, held over nine days in early October, is often called the largest balloon festival in the world. Its mass ascensions send hundreds of balloons up in waves after dawn, and at evening glow events the balloons stay on the ground and fire their burners so the envelopes shine like lanterns. The Bristol International Balloon Fiesta in England, held each August, is one of Europe's largest, with mass launches at dawn and in the evening, weather permitting. Those times are no accident: balloons fly best in light wind, which usually means around sunrise or toward evening.

How daubday's balloon pictures are built

Every picture in the theme is generated from a seed and shares one structure:

• The scene. One of several background designs, from plain to checked, sits behind a hill line and three puffy clouds made of overlapping circles. About half the pictures are mirrored left to right.
• The balloons. There are two to five. The first is always a large one near the middle; the others are smaller and scattered around it.
• The envelope. Vertical stripes in two alternating colors, five on the big balloon and three on the small ones. In the flat picture they are straight bands, not curved gores.
• The band and basket. A horizontal band crosses each envelope just below its widest point, and a small basket hangs a little below.

Coloring tips

1. Start with the big balloon. Its stripes are the clearest shapes, so the scene takes shape fast.
2. Check both sides of the band. The band cuts most stripes into separate upper and lower pieces with the same number, so after filling the top of a stripe, look below the band for its other half.
3. Sweep bands and baskets. All the bands share one color and all the baskets share another, so select one and visit every balloon. With four or five balloons, some also repeat a stripe color pair.
4. Use Hint for small baskets. The baskets on the smallest balloons are among the tiniest areas. If a color will not finish, tap Hint, and see the guide on small areas.
5. Save the sky for last. The background, hill, and clouds are large, easy areas for a calm finish.

When you finish, the replay shows the balloons appearing in the order you colored them; sharing your art explains how to save it. For why alternating stripe colors look so lively, read color basics.