Blimps for the Everyman

A heap of rip-stop nylon, damp with dew, stretches 140 feet across a farmer’s hay field in Amherst, Massachusetts. The pre-dawn air is humid, still, and cool — “perfect weather for this kind of thing,” says one of the volunteers bustling around the lumpy shape. A large fan roars to life, drowning out the twittering of the birds and frogs, and the nylon gradually leavens toward the sky, growing into a blob 70 feet high. Inside its bobbing skin, experimental blimp-builder and pilot Mike Kuehlmuss stands in a makeshift cockpit of welded steel tubing. He hits a toggle, and with a roar a jet of burning gas shoots upward.

With aching slowness, the watermelon-shaped envelope lifts off the ground, its jaunty black and yellow stripes and red tail fins bringing to mind something of a carnival jester. Crew members hold the cockpit steady as Kuehlmuss straps himself into a bucket seat salvaged from an old Toyota Corolla. He checks the instruments fastened to the frame in front of him: envelope temperature, fuel levels, compass heading, engine rpm. With a remote switch he triggers another blast of hot gas, then checks the view of from the camera fastened near the near-mounted propellor. All systems are go. The burners roar, and the cockpit levitates off the ground. The 24-hp engine sputters into action, and with all the stateliness and grace of a passing cloud, the huge ship slowly rises and slides away into the sky. The Skyacht – the first of what its builders hope could be an entire industry of personal recreational blimps – is again on the prowl.

The dawning of an age of airships has been a magnificent dream since 1900, when Count Ferdinand von Zeppelin flew his first dirigible above Lake Constance in Germany. Efficient and majestic, airships of the Golden Age made up for in romance what they lacked in speed. The Hindenburg’s passengers enjoyed a leisurely lifestyle that played out in a spacious complement of public rooms, including a lounge, a writing room, a dining room with seating for 50, a pressurized smoking chamber, and a music salon outfitted with an aluminum piano. The heyday of the airship, however, was short-lived. The great craft were finished off as much by the success of winged airliners as by the Hindenberg’s famous demise. They still fly, of course — Goodyear operates a fleet of three — but they’re relicts of an otherwise vanished fauna, a kind of technological coelocanth.

All the more remarkable then, that more than a century after the first zeppelin a radical new vision of tomorrow’s airships is taking to the skies. Much of the impetus springs from the fertile mind of Dan Nachbar, a former Bell Labs engineer who as a hobby enjoys flying Cessnas. In 2001, Nachbar was taking a long cross-country trip from Texas back to his home in Amherst in a single-engine Skyhawk. The view was spectacular, but he felt that his enjoyment of it was spoiled by the noise of the engine. And that set him to wondering would be the the quietest way to enjoy flying.
The answer he came up with: a blimp. But no ordinary blimp. One that would overcome the major stumbling block of previous airships, namely the problem of the lifting gas. Hydrogen, the lightest element, is dangerously combustible. Helium, though inert, is expensive. Nachbar recognized that if an airship used hot air, as balloons do, you could just let the air escape at the end of each flight, fold up the envelope, and store it away.

Needing help to turn this vision into a reality, Nachbar enlisted the help of inventor John Fabel, who happens to be a neighbor in his communal living project near the University of Massachusetts. A specialist in efficient fabric tension structures, Fabel quickly sketched out a design concept. To help make the plan a reality, Nachbar called in Kuehlmuss, who worked at a nearby airfield as a mechanic. Starting with models, the team tested and tweaked their ideas until at last they were ready to start building the real thing. By October, 2006, the craft went aloft on its maiden flight.
“I want to fix the world of the blimp,” says Nachbar. “Here you have a corner of aviation that has been dormant for decades, for generations. What we’ve come up with is a disruptive technology.”

AS POTENTIALLY TRANSFORMATIVE AS NACHBAR’S VISION may be, he didn’t come up with the idea for a hot-air blimp. In fact, such craft have been popular in Europe as advertising vehicles since the ‘70s. But these models are expensive and cumbersome. The true potential of the idea could only be unlocked if the craft could be made light, inexpensive, and easy to use so that it can be put in reach of the mainstream – a sort of hybrid of hot-air balloon and ultralight airplane.

A hundred miles up the Connecticut River valley from Amherst lies the sleepy village of Post Mills, Vermont. Here, at a grass airstrip on the edge of town, lives Brian Boland, a lanky, bearded tinkerer and aeronautical pioneer. One of the first generation to take up hot-air ballooning, Boland has racked up more hours in the sport than any other American. And since 1973, he’s also been pursuing the dream of hot air blimps. Over the years has stitched together seven different models. His consistent goal has been simplicity and ease of use: to create lightweight, transportable craft that a single person can set up and enjoy with minimum hassle.

On a recent summer morning, Boland inflates his latest version, a lumpy mass the size of a school bus that resembles nothing so much as a pair of 80-foot-long, bright orange lips. His wife Louise, with poetic simplicity, has dubbed the craft “Lips.” Its main virtue, however, is not aesthetic, but practical. The envelope can be rolled up and stored in a bag small enough to load into the back of a small car. Inflating it requires just a few minutes and the assistance of one or two helpers.

The design, however, has a major shortcomings. Because the burner needs fresh air to burn, the envelope can’t be closed and pressurized like a helium blimp. Without this overpressure to give the envelope its shape, Boland’s blimp is baggy, with a somewhat down-on-its-luck appearance. The nose tends to mush in at any speed higher than a few miles her hour. The highest wind speed he can operate in, Boland says, is “dead calm.”

Boland gives a yank on a 6 h.p. Briggs and Stratton 2-stroke engine, and the 30-inch wooden prop buzzes to life. With a burn of propane, Lips rises and sweeps off into the blue sky. Over the next half hour, the craft rises and descends, turning sprightly figure eights at the speed of a leisurely jog. It’s like a big floating marshmallow, and when Boland pulls on the big inflated rudder, it doesn’t bend so much as mush into a curlicue.

He toodles along over the field and pass above the red barn that serves as his workshop. The top floor is a loft where he sews his balloons. The ground floor is a dog’s dinner of unusual historical artifacts: a three-wheeled Messerschmidt car, a 1930s-era flight simulator powered by pneumatic tubes, a wheeled Viking ship built on the chassis of a Chevy Astro van.

Touching down, Boland calls over to Louise to add ballast to the canvas bag hanging from the nose of the airship. “Four more beers,” he yells. “No, make that six.” She runs inside to the fridge and comes out with the requested cold ones, which make the nose hang a touch lower. Boland pronounces himself pleased. “They’re just the right weight,” he says. “Plus, you never know when you’ll need a beer.” With a yank on the starter cord, he takes off again.

Though he’s clearly having fun, Boland disavows any hope that hot-air blimping might be the recreational pastime of the future. In fact, in the last 33 years, he’s only sold one blimp. “People call up from time to time and ask about buying one, but I end up talking them out of it, because of how piss-poor the performance is,” he says. “It would be disastrous to get into it without having a lot of hot-air balloon flying experience.”

NACHBAR HAS A TOTALLY DIFFERENT VISION for the Skyacht. Though he credits his blimp-building rival with giving him inspiration and advice, he believes that Boland isn’t dreaming big enough. “He’s an artist,” he says. “I’m an engineer. That makes a difference in how we approach problems.”

In order to overcome Boland’s bagginess issue, Nachbar and his team have come with a system of six aluminum stiffening ribs that run from the Skyacht’s nose to its tail, with the two ends connected by a cable along the central axis. Spreading out the fabric like the ribs of an umbrella, the system adds substantial rigidity without adding much weight. It also allows the blimp to carry a large engine in its tail, directly in line with its aerodynamic axis, instead of hanging inefficiently off the back of the basket, as Lips’s does.

As the Skyacht buzzes around the pre-dawn sky over Amherst, its 670-cc utility engine seems tiny, a gnat pushing at the elephantine mass of the airship. Indeed, Nachbar’s blimp is just as slow as Lips (though he believes that by swapping in a more powerful aircraft engine he could achieve speeds of up to 30 mph). Where the Skyacht clearly excels is in maneuverability. Thanks to steerable thrust, it can pretty much hover in place and rotate on its own axis.
Drawing to a stop at the far end of the field, pilot Mike Kuehlmuss descends to hover just above the topmost branches of a maple tree. In Nachbar’s reckoning, the ability to pluck any given leaf from any given tree is a particularly apt demonstration of the Skyacht’s unprecedented maneuverability. Unlike a hydrogen or helium it can control its buoyancy with great precision, and  unlike a helicopter it produces no downwash. And in fact, Nachbar sees a potential market for leaf-plucking. “There are people called rainforest researchers that really want to do that,” he says.

In solving Boland’s performance problems, however, Nachbar has taken on another. With its elaborate system of ribs and cables, the Skyacht is far bulkier and more labor-intensive to assemble than Lips. “If it’s going to take a whole day to initially set the thing up with an army of people, I don’t want to know about it,” says Boland. “I think the novelty will wear off pretty quick.”

Certainly, the Skyacht will never fit into the back of a hatchback. But Nachbar insists that once the major kinks are worked out, the team will move on to refinements like an easier-to-assemble rigging. Ideally, he says, it should take a crew of three as little as two hours to assemble and inflate a Skyacht from a package that can fit in a 20-foot trailer. Other slated improvements: an electric motor, for quieter running, and a new burner system that will also make less noise. After more tinkering and refining, he hopes to obtain approval from the FAA to build and sell models to the public.

“I can’t tell you how many people have sent me emails saying, ‘I want one!’” Nachbar says.

Recreational blimping could just be the beginning. A vehicle like the Skyacht would be ideal for any purpose that requires moving low and slow with minimal noise. It could be used as a platform for movies and TV cameras, or for mineral-prospecting sensors. Scaled up, a hot-air blimp could be used to transport massive infrastructure components like bridge and pipeline segments too large to be moved any other way. “No one’s going to shelve their 747 for a blimp,” Nachbar says. “But for specialized applications, this technology could be dominant.”

Selling blimps to the public requires getting approval from the FAA, a process that can take years and cost millions of dollars. But Nachbar isn’t put off. “I call this a personal blimp, and I mean it in the same way that we say “personal computer.” It’s useful for recreation, but for a lot of other things as well. It’s going to change the paradigm of how this kind of aviation, in the same way that the PC changed the paradigm for computing.”

[This story originally ran in Popular Mechanics]

Below: Lips takes off from Post Mills, VT.

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