When we think of the first human forays into flight, two brothers come to mind, named Orville and Wilbur. However, it may be more correct to think of two other siblings from the 1700s: Jacques-Étienne Montgolfier and Joseph-Michel Montgolfier and their 1783 discovery, the hot air balloon.
“The purpose of the fabric is to hold air,” said Andy Richardson, owner of hot air balloon manufacturer National Ballooning LTD in Albuquerque, New Mexico. “The balloon has a load building structure and the webbing works almost like an exoskeleton. When you design a balloon, you take into account the stress of the fabric, the cable the balloon runs into, and the basket.”
The first balloons were made mostly of silk and paper, he said, and hand-sewn together, using smoke and wood fire to provide heat but “only heat in the ground is used and the travel is very short.”
Model of the Montgolfier brothers balloon at the London Science Museum.
Despite the success of the past centuries, it is as recent as the 1960s that the hot air balloon has really become popular. “The US government hired Ed Yost to see if he could make balloons to get troops over the Iron Curtain. But balloons can only be so calm. But while it may not work for military purposes, Yost doesn’t lose the balloon itch. He helped form Raven Industries to making it a recreational sport and hot air balloon is now known for it as well as a leading source of marketing.
So how are balloons made today?
“It used to fire on the ground to make it run but it was replaced by propane,” said Richardson. “The burners are loosely modeled on the thrusters of the shuttle.” The burner has a coil and when you hit the blast on the burner, he says, it allows the propane to get out of the tank, through the hose, and into the burner. The propane goes up and runs to the bottom of the burner where the jets are. “It superheats propane and gives you three times the amount of power if you just took raw propane and burned it,” he adds.
One helpful addition was the chute valve added in the mid-1970s, which allowed air to escape through the parachute for easier landing. “It just pulled the parachute down from the webbing on [the balloon],” he said. “Before that it had looped velcro panels on the sides of the balloon, but the whole balloon deflated. But now the air pushes it closed so it resets itself.”
The panels for balloons, designed by a CAD program, perform stress analysis to ensure the fabric is not overstressed. Each gore panel on the balloon has anywhere from 8-17 trapezoidal panels. Most companies use AutoCAD or Rhino 3D computer programs to design, he added.
How quickly can a hot air balloon climb?
Interestingly enough, one area that is still the same is the basket. “At that time rattan and now rattan,” he said. “They tried to use fiberglass, an aluminum composite material, but they got it right the first time.”
A typical hot air balloon ride is one hour from the first few hours at sunrise or the last few hours before sunset, and can range in height from treetop level to 3,000-5,000 feet. While the balloon is traveling relatively slowly, it is possible for the wind speed to bring it up to 120 mph. “Even then it can seem like you’re not even moving,” he said.
Richardson says the FAA wants future designers apprenticed with a certified balloon instructor for 18 months to study the entire process from start to finish before pursuing balloon building, a craft that has been centuries in the making.