Sergei Brin’s airship has received FAA Clearance:
Expect traffic on the 101 highway in Mountain View, California, to be even worse in the days or weeks ahead, as motorists slow down to watch Google co-founder Sergey Brin’s 124-meter long airship Pathfinder 1 launch into the air for the first time.
IEEE Spectrum has learned that LTA Research, the company that Brin founded in 2015 to develop airships for humanitarian and cargo transport, received a special airworthiness certificate for the helium-filled airship in early September.
That piece of paper allows the largest aircraft since the ill-fated Hindenburg to begin flight tests at Moffett Field, a joint civil-military airport in Silicon Valley, with immediate effect.
The certificate permits LTA to fly Pathfinder 1 within the boundaries of Moffett Field and neighboring Palo Alto airport’s airspaces, at a height of up to 460 meters (1500 feet). That will let it venture out over the south San Francisco Bay, without interfering with planes flying into or out of San Jose and San Francisco International commercial airports.
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Twelve electric motors distributed on the sides and tail of the airship, and four fin rudders, allow for vertical takeoff and landing (VTOL) and speeds of up to about 120 kilometers per hour. A tough layer of laminated Tedlar material contains 13 helium bags of ripstop nylon, which contain lidar systems to track the gas levels within.
Pathfinder 1 has a hybrid propulsion system, with two 150 kilowatt diesel generators working alongside 24 batteries to provide power for the electric motors, according to a recent presentation by LTA’s CEO, Alan Weston. He said that LTA has plans to use hydrogen in later versions of the airship, perhaps as fuel for future fuel cells or turbogenerators, and possibly even as a lifting gas.
LTA’s Pathfinder 1 carries bigger dreams than hovering over a sports stadium:
Pathfinder’s cigar-shaped envelope is just over 120 meters in length and 20 meters in diameter. While that dwarfs Goodyear’s current, 75-meter Wingfoot One, it’s still only half the length of the Hindenburg. LTA expects Pathfinder 1 to carry approximately 4 tonnes of cargo, in addition to its crew, water ballast, and fuel. The airship will have a top speed of 65 knots, or about 120 kilometers per hour—on par with the Hindenburg—with a sustained cruise speed of 35 to 40 knots (65 to 75 km/h).
It may not seem much of an advance to be building an airship that flies no faster than the Hindenburg. But Pathfinder 1 carries a lot of new tech that LTA is betting will prove key to an airship resurgence.
For one, airships used to be constructed around riveted aluminum girders, which provided the highest strength-to-weight ratio available at the time. Instead, LTA will be using carbon-fiber tubes attached to titanium hubs. As a result, Pathfinder 1’s primary structure will be both stronger and lighter.
Pathfinder 1’s outer covering is also a step up from past generations. Airships like the 1930s’ Graf Zeppelin had coverings made out of doped cotton canvas. The dope painted on the fabric increased its strength and resiliency. But canvas is still canvas. LTA has instead built its outer coverings out of a three-layer laminate of synthetics. The outermost layer is DuPont’s Tedlar, which is a polyvinyl fluoride. The middle layer is a loose weave of fire-retardant aramid fibers. The inner layer is polyester. “It’s very similar to what’s used in a lot of racing sailboats,” says Taussig. “We needed to modify that material to make it fire resistant and change a little bit about its structural performance.”
But neither the materials science nor the manufacturing advances will take primary credit for LTA’s looked-for success, according to Taussig—instead, it’s the introduction of electronics. “Everything’s electric on Pathfinder,” he says. “All the actuation, all the propulsion, all the actual power is all electrically generated. It’s a fully electric fly-by-wire aircraft, which is not something that was possible 80 years ago.” Pathfinder 1 has 12 electric motors for propulsion, as well as four tail fins with steering rudders controlled by its fly-by-wire system. (During initial test flights, the airship will be powered by two reciprocating aircraft engines).
There’s one other piece of equipment making an appearance on Pathfinder 1 that wasn’t available 80 years ago: lidar. Installed at the top of each of Pathfinder 1’s helium gas cells is an automotive-grade lidar. “The lidar can give us a point cloud showing the entire internal hull of that gas cell,” says Taussig, which can then be used to determine the gas cell’s volume accurately. In flight, the airship’s pilots can use that information, as well as data about the helium’s purity, pressure, and temperature, to better keep the craft pitched properly and to avoid extra stress on the internal structure during flight.
Although LTA’s initial focus is on humanitarian applications, there are other areas where airships might shine one day. “An airship is kind of a ‘tweener,’ in between sea cargo and air freight,” says Taussig. Being fully electric, Pathfinder 1 is also greener than traditional air- or sea-freight options.
Because Pathfinder uses Formula 1 level technology, even when it enters series production don’t expect change from $50 million each. In contrast a Herc has four times the payload at a cost of around $20 million. This is just a rich man’s toy. Nevertheless I like the idea of a return of the liner concept dating from a more gracious time.
The eternal nemesis of lighter-than-air ships is high wind. They are the ultimate fair weather vehicle, which severely limits where and when they can operate.
They are toys.
Okay, Google: what are the Elon’s rocketships made of?
The FAA limitations in altitude are a bit backwards. One of the primary dangers to airships is the weather and being forced down into the ground by it.
That said, there is a LOT more experience with blimps at low altitude (via the Goodyear airships) since the Zeppelin era, decades of it. Hopefully LTA is smart enough to take advantage of that.