Airships Rise Again (2021)
Here&#x27;s how to think about airships using numbers.<p>You need about 1000 liters of helium or hydrogen to lift 1kg of cargo (the difference is only about 10%, despite the fact that H2 is twice as light as He they are both so much lighter than air, that you can almost think they are weightless, so all that matters is the mass of air displaced).<p>Let&#x27;s say you want to lift 1 ton. You need a cube of balloon that&#x27;s 10m x 10m x 10m. Let&#x27;s put 4 of those next to each other, so you can lift 4 tons with a box-shaped balloon that&#x27;s 40m x 10m x 10m. Let&#x27;s make it a cylinder instead, and make the Soviet assumption that pi=3, we end up with a cylindrical balloon that&#x27;s 40m long and 10m tall and can lift 3 tons. Since the ends of an actual dirigible are not quite flat, let&#x27;s say you need a 50m long and 10m tall dirigible to lift about 3 tons. The ratio of lengt&#x2F;height of Hindenburg was 7:1 and of Graff Zeppelin was 6:1. Current Goodyear blimps have a ratio of about 4:1.<p>So our intuition building block is a dirigible that&#x27;s 50m long and 10m tall and can lift 3 tons.<p>Multiply that by 10 in all dimensions and you get a 500m long by 100m tall giant that can lift a whopping 3000 tons of cargo.<p>Multiply by only 5 in all dimensions and you get a 250m long by 50m tall dirigible that can lift 375 tons of cargo. That is a large dirigible, but not impossibly large. That was roughly the size of Hindenburg: 41 m tall and 245 m long.<p>Hindenburg was build 100 years ago. We can probably build one like that nowadays for much less. How about one that&#x27;s double in size in all dimensions? I find that conceivable. And such a dirigible would have 3000 tons of lift. Can you imagine that? For comparison, the cargo capacity of the famous Liberty ships was about 4300 tons. You could get airlift capacity that&#x27;s only available nowadays as sealift.