In practice, as airship designers scale up their proposed designs, they tend not to grow just the payload, but also the features. Increasing the length to 8, though it’s only a 14% increase in length, and a 31% increase in cost of construction materials, more than doubles the payload, and the next two increments in length nearly double it again, so that the length-10 airship, though less than half again as long as the length-7 airship, and only twice as costly in construction materials, has nine times the payload capacity! By length 7, it can carry about one-sixth of the weight of the frame as payload. At just above 6, say length 6.1, it can carry a small payload. At that point, it can only just fly, and has no room for any payload at all. In the example shown in Table 1, the airship can’t fly at all until it reaches a length of 6. Table 1, below, shows the pure math of how lift overtakes weight and creates payload, using unitless numbers to keep it abstract rather than tying it any actual, particularly airship design: For that payload to be very large, an enormous amount of lifting gas needs to be contained.īut there's more to it than that, because the lift of an airship, for a given design, is roughly proportional to the volume, while the weight of an airship is roughly proportional to the surface area. The difference between the lift from the gas and the weight of the frame and equipment becomes the usable payload. An airship can't fly until it contains enough lifting gas that its lift is more than the weight of the frame and equipment that comprise the airship and give it its functionality. A thousand cubic feet of hydrogen or helium can lift about 100 pounds. One cubic foot of hydrogen weighs about one-twentieth of that, so most of the weight of the displaced air turns into lift. One cubic foot of air weighs less than one tenth of a pound. Lifting gas creates lift by displacing air. But not only are the market small, the small airships are technologically quite different, and much less useful, than the giant airships that could revolutionize global transportation, so different that they can hardly even serve as proper prototypes.įirst, it takes a lot of lifting gas to lift much of anything. There are markets for small airships, like advertising and surveillance, and aspiring airship builders sometimes try to survive on these while they chase bigger dreams. Consequently, the good old-fashioned model of a visionary entrepreneur pulling himself up by his bootstraps and slowly, patiently building an empire while winning investors’ trust along the way can't work for airships. Venture capitalists in Silicon Valley are constantly on the lookout for this kind of idea, which can start small, and indeed may be brought almost to maturity by a handful of founders, and then can massively scale up.Īirships have a major scalability problem, too, though it's the opposite of the usual one. The great high-flying companies of recent decades, like Google, Amazon, and Facebook all have this property: that their central concepts and technologies can be, and were, implemented on a small scale at first, and then could grow to a limitless extent at modest or slight marginal cost. Scalable successes are far more transformational and profitable than things that only work well once or a few times or on a small scale. If a successful project isn’t scalable, that is a sad limitation on its value. Sometimes success isn't scalable because it depends on a single personality or unique local conditions. Scalability is good because it means success can be reproduced. Often, when something is successful, people ask if it is scalable. The enormous size of airships is the biggest barrier to the re-emergence as a major mode of transportation. Considering that, it stops seeming strange that the Airlander 10 was considered only a “prototype.” The Graf Zeppelin, a German airship that ran regular transatlantic commercial flights between 19, was 776 ft long. The recently built British hybrid airship Airlander 10, which first flew in 2012, was almost 300 ft long, and was the largest aircraft in the world before it was retired after wind damage in 2016. The most counterintuitive thing about airships is their immense size.
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