Flying with Helium Balloons:
Basic Technique and Personal Impressions

Like hot-air balloons, cluster balloons are flown in the very early morning, when winds are calm. In some areas, it is also possible to fly in the evening, in the hour or two before sunset. Preparations for a morning flight flight start before dawn. The balloons range in size from four to seven feet; depending on the mix of sizes, anywhere from 50 to 150 balloons may be needed. It takes a crew of fiften to twenty people about an hour and a half to inflate the balloons. Special hoses and manifolds are used to inflate the balloons to the desired size, based on the volume of the helium tanks. The inflated balloons are sealed using tape and cable ties, and are tied with nylon twine.

You watch the balloons swell and sway and grow taut and huge in the darkness, then get attached to their strings and tied down to sandbags, like a field of giant flowers blossoming there in the dark. There's a lot for everyone to do. It's wonderful to have friends who will drive out into the countryside in the middle of the night, just to help you fly!

After all the balloons are inflated and secured to sand bags, the cluster balloons is "assembled". Simply attaching all the balloons directly to the pilot would result in tangled strings, making it difficult to reliably cut away balloons for maneuvering. Instead, the balloon are attached in groups of four or more to the ends of long nylon straps called risers; the risers are then attached to the pilot's harness. Different length risers are used to hold the balloons at different heights, in layers. More balloons are attached directly to the pilot's harness.

There's a sense of anticipation as the balloons are attached to you, and you grow lighter and lighter. The balloons are so big, it's like being a child again, and small. You're paying attention to the details, making sure everything is being rigged correctly. But even after you've done it many times before, there's still something a bit unreal to it. You wonder: am I really doing this?

The pilot is in a harness designed for paragliding, which includes a rear-mounted emergency parachute. The pilot can stand up in the harness to take off or land; there's also a little seat built into it, for greater comfort while flying. Bags of water ballast hang beside the pilot, and are used to maneuvering (see below). The pilot also carries an altimeter/rate-of-climb instrument, a GPS and a two-way radio.

After you go through your checklist of equipment, the crew attaches the last of the balloons to your arms, legs and feet. It's not necessary to attach them that way -- it's just fun to feel the pull of the balloon strings wrapped around your hands, and the weightless sensation of your legs being pulled out behind you, with your toes just brushing the ground....

With the pilot tethered to the ground, the amount of ballast is adjusted so that the cluster balloon is just slightly buoyant, with just a pound or two of net lift. This allows for an initial rate of ascent of 100 - 200 feet per minute. Crew prepare to release the ground tether at the pilot's signal.

The tether is released, and up you go.... The ground below drops away. If you're at a balloon festival, the crowd is cheering for you, and you wave to them. And your balloons lift you smoothly and silently into the sky.

To control the altitude of the cluster balloon, the pilot takes off with more balloons than needed to lift his or her weight, and carries ballast (water or sand) to balance out most of this excess lift. To level out or descend, the pilot releases or bursts balloons. To slow the descent or ascend again, the pilot releases ballast. The number of times the cluster balloon can ascend or descend is limited by the amount of ballast and extra balloons carried. The balloon may also gain a certain amount of lift during the flight due to solar heating of the balloons.

Dropping ballast to make yourself lighter, you let the balloons lift you higher and higher.

A cluster balloon moves in whatever direction the wind carries it. However, as in a hot-air balloon, the direction of flight in a cluster balloon can be controlled to some degree by using the different wind directions that exist at different altitudes. During the early morning, it is not uncommon to have a variety of different wind directions available at different altitudes, so a good amount of "steering" may be possible. Launching a toy balloon prior to flying allows the pilot to see the wind directions that exist at different altitudes, in order to plan the flight. During the flight, the pilot can watch any nearby hot-air balloons, to note their direction of motion at different altitudes. A portable GPS unit is also useful.

There's nothing as serene and beautiful as floating a mile or two above the earth with a huge, colorful balloon bouquet.

To make best use of the limited number of changes in rate of ascent/descent available, the pilot often starts the flight by an ascent to altitude, noting the wind directions at different altitudes on the way up. Latex balloon clusters have been flown as high as 20,000 feet; however, for a recreational flight, a maximum altitude of 3,000 - 5,000 feet is more common. After reaching the maximum desired altitude. the pilot levels out, and then descends to the altitude that had the wind direction that will take him in the direction he desires. Usually, the pilot tries to head away from cities and particularly airports, toward areas where there are suitable fields for landing and good road access for the chase crew. The pilot may change altitude several more times during the flight to adjust course.

You float over the clouds. A hot-air balloon flies alongside you. You drift over hills and valleys, over woods and orchards.

On approach to landing, the pilot levels out at 100 feet or less, heading in the direction of an appropriate field or open area. The chase crew is directed out ahead of the balloon to meet it at landing. This is the most challenging part of the flight, since the greatest risk of injury is from striking powerlines or other obstacles at landing. Considerations in landing are similar to those in a hot-air balloon, except that it is more difficult to rapidly change rate of ascent or descent, and the number of landing attempts is limited by the available ballast. If crew are present at landing, they can easily stop the motion of the balloon by grabbing the pilot's harness, or by use of a drop line. If crew are not present, the pilot can land and stabilize the balloon by himself in light winds. In windier conditions, the pilot may have to cut away or burst many balloons to stop from dragging.

Coming in over the trees, ready to throw a drop line to the crew, who you hope are there -- it's not more than 10 mph of wind, but you really don't want to drag several hundred feet at 10 mph through a cornfield.... And there they are, and you thrown the line, and someone grabs it and slows you down, and you burst a few balloons to drop in gently to the ground. It's good to be on the ground.

After the flight, the balloons are deflated. Some types of latex balloons are safely reusable for several flights; others can only be used once. Balloons that are being discarded are burst rather than released, for environmental reasons and to avoid creating a hazard to aircraft.

Click here for a QuickTime slide show featuring these and many additional images (8.6 MB)

Click here for a QuickTime video of the launch of a cluster balloon (6.9 MB)

Photography: Chris Howell (Bloomington Herald-Times), Louie Psihoyos, Dean Ekdahl, Ernie Hartt, Barry Nation, Borrowed Light Images, Matt Volke, John Ninomiya