When passengers took off from Friedrichshafen, Germany on October 11, 1928 for the world’s first nonstop, transatlantic commercial flight, they didn’t embark upon the voyage from their seats on an airplane. Instead, they sat aboard the Graf Zeppelin airship en route to NAS Lakehurst in New Jersey, where they would successfully land four days later.
DELAG’s hydrogen-filled rigid airship continued flying passengers across the North and South Atlantic throughout most of the 1930s, as did several German zeppelins, including the Hindenburg. That ship made three dozen transatlantic passenger flights until it caught fire while attempting to dock in Lakehurst on May 6, 1937, killing 36 people.
The Hindenburg disaster marked the dramatic end of the airship’s brief tenure as a popular form of passenger travel. By the end, however, cheap fossil fuels made planes a faster, less expensive option than dirigibles anyway. If the Hindenburg hadn’t put the airship industry to pasture, evolution would’ve eventually finished the job.
But now that the transportation sector is looking for serious ways to cut carbon emissions, dirigibles are attempting to make a comeback. They’re still slower than jet travel, sure, but for cargo that doesn’t need to arrive in hours (to then languish in warehouses for days or weeks), slightly slower travel makes a whole lot of sense.
Last year, a study from scientists at the International Institute of Applied Systems Analysis (IIASA) in Laxenburg, Austria found that airships could play a role in fighting global warming. Around a quarter of the world’s carbon dioxide emissions stem from transportation, with boats representing around 3 percent of that total.
The study proposed utilizing jet streams—those meandering air currents within Earth’s atmosphere that move all across the planet—to transport a combination of cargo and hydrogen, using airships or balloons at low altitudes. Using high wind speeds and reliable direction, the researchers found “hydrogen-filled airships or balloons could carry hydrogen with a lower fuel requirement and shorter travel time compared to conventional shipping.”
Airships have another big shipping advantage: Planes require, at minimum, landing strips, hangars, and roads to get the stuff they carry to where it’s going. While early airships relied on similar infrastructure, this new generation of giant flying blimps can zip from point to point and land anywhere, including ice sheets, beaches, meadows, deserts, and even atop water.
It’s this ability to get to places that don’t have roads that has drawn both private businesses and governments back to airships. Plus, they can fly over the infrastructure-destroying effects of climate change: As flooding and wildfires occur at an increasing clip, being able to deliver emergency supplies to areas that have been hit hard—without having to rely on roads or rails—is promising.
So why did it take the world this long to dust off such an old mode of transportation?
Back in the heyday of airships, landing required a mooring structure attached to the ground and a team of strong people to grapple with the ropes that attached them. The tallest airship mooring mast by far was the top of the Empire State Building; engineers added an extra 200 feet to the skyscraper in 1931 just to serve Graf Zeppelins. But the location proved too windy (and perhaps elevated) for unloading human passengers who were to walk across a gangplank, even if the midtown location was more convenient than the airship landing field in Lakehurst.
Mooring masts were never a great idea in the first place, says Bob Boyd, the hybrid airship program manager at Lockheed Martin Skunk Works. “A master tower does not hold the airship in a fixed attitude to the ground—it allows for kiting into the wind and up and down ‘floating’ motion on even fairly small wind gusts,” he says. “This makes loading and unloading cargo problematic.”
If we want to make a dent in reducing fossil-fuel emission, we also want larger airships than we had in the past; after all, the bigger the airship, the more it can carry. Design a dirigible 10 times longer and wider and it can haul 1000 times more cargo. But that means a wider, taller mast, all of which is more expensive, and much less portable.
Enter Lockheed Martin’s air-cushion landing system (ACLS) which uses hovercraft technology to enable its hybrid airships to land on a variety of non-paved surfaces, including water. Working with, as Boyd details, “several designers who understand the rare arts of hovercraft engineering and lightweight soft structure manufacture” over a two-decades-plus time period, ACLS’s three underbody hoverpads create a cushion of air beneath the ship that allows it to float over the landscape.
Plastic fingers hang down from the hoverpads at the bottom of the ship and create a seal with the ground, meaning the airship can taxi over small obstacles like rocks or bumps. This offers flexibility in where the airship can land, and has minimal long-term impact on the site. Best of all, after the airship is in its landing position, it can reverse the hoverpads so the airship can “grip” to the surface of the land, sand, ice, or water.
Tech borrowed from hovercrafts wasn’t originally an obvious choice. Boyd says the idea came from some young engineers on the design team after they had struggled with a more traditional concept for landing: wheels based on aircraft weight.
“Initially,” says Boyd, “we tried using these equations and sized some rather large gear trucks, but quickly realized that we were making a simple mistake. The landing event isn’t actually driven by weight, but by … the momentum of the descending airship, which is much more massive than its apparent weight.”
The landing tech was also a “critical breakthrough that vastly reduced the mass of the landing system to a workable scale,” Boyd says. Ideally, an airship carries landing gear along with it, but that adds both significant and unevenly distributed weight—neither of which are ideal.
ACLS doesn’t have this issue because its weight is “spread over a large area of the airship hull via the air compressed inside the trapped ‘piston’ of the ACLS pad,” says Boyd. “The load is imparted directly into the airship hull over a wide area, so it does not impact the weight of the hull which has been designed to contain the pressure load from the helium (acting in the opposite direction).”
Other companies are using different tech to solve the same problems. Flying Whales, a France-based airship company, makes the LCA60T, capable of carrying 60 tons. It doesn’t need landing gear—because it doesn’t land.
The ship is meant to hover 160 feet above the pickup and drop off areas. Then, “the cargo door will open up, to allow for the payload system to be released,” says Michèle Renaud, Head of Marketing and Sales for Flying Whales. “So no infrastructure or flat area [is] needed.”
This means the ship is “dedicated to operate in difficult to reach areas, like mountainous areas, and wherever infrastructures are lacking.” To service, refuel, or change crews on the airship, it does need to be moored to the company’s proprietary airdock.
From their unlimited potential to haul all kinds of cargo to the important role they could serve in relief efforts, airships might someday become as widely used as they once were before airplanes took over. And if that happens, it’ll be because of these new landing technologies.