Thanks, I think the crux is economies of scale, both in size of the airship and production rate. That paper assumes the same cost as the Zeppelin NT, and its cost estimate is 93% airframe cost. The assumption is that the airframe cost per kg is the same as the Zeppelin NT, of which only 7 have ever been built. The Eli Dourado article imagines huge economies of scale, with airships 5x larger than the study, 25,000 units and a cost around $100 million per unit or ~12x lower per kg.
I would guess scaling is unlikely to work because it requires hydrogen, but there’s so much money available to solve at least the technical problems.
There are a bunch of papers and approaches you can take. Another approach is estimating airship costs from manufacturing costs of Boeing/Airbus; this requires a good understanding of manufacturing processes and aircraft design, but anyway, the costs per payload capacity seem comparable for equal levels of competence and manufacturing scales and experience with manufacturing. And airships are much slower, and you have to deal with ballast issues. Could you build airships cheaper than that? Probably, yeah, but you could also build regular aircraft cheaper than that, too.
Bigger ships aren’t necessarily cheaper to build. You need bigger facilities, and there are square-cube laws, you need to transfer forces over larger distances. Yes, the same is sort of true for aircraft, but if scaling up means more of the fuel can go in the wings, then square-cube laws don’t apply the same way.
Using hydrogen isn’t really a safety problem, but it is a regulation and PR problem.
No matter what the cost of airships is, they’re obviously better when you want duration or volume than when you want ton-miles. So you target the applications that make more sense first, and then if that works out well, you can think about other applications and have more data to evaluate them. Eli does not think this way. He goes straight to “let’s build a million huge cargo airships!!!” and he also doesn’t know shit about aircraft design, which is a deep and multidisciplinary field with extensive research into it. So, why would people take him seriously?
Aircraft costs per ton-mile are variable, but here is a report from American Airlines showing $0.33/ton-mile in 2018.
Thanks, I think the crux is economies of scale, both in size of the airship and production rate. That paper assumes the same cost as the Zeppelin NT, and its cost estimate is 93% airframe cost. The assumption is that the airframe cost per kg is the same as the Zeppelin NT, of which only 7 have ever been built. The Eli Dourado article imagines huge economies of scale, with airships 5x larger than the study, 25,000 units and a cost around $100 million per unit or ~12x lower per kg.
I would guess scaling is unlikely to work because it requires hydrogen, but there’s so much money available to solve at least the technical problems.
There are a bunch of papers and approaches you can take. Another approach is estimating airship costs from manufacturing costs of Boeing/Airbus; this requires a good understanding of manufacturing processes and aircraft design, but anyway, the costs per payload capacity seem comparable for equal levels of competence and manufacturing scales and experience with manufacturing. And airships are much slower, and you have to deal with ballast issues. Could you build airships cheaper than that? Probably, yeah, but you could also build regular aircraft cheaper than that, too.
Bigger ships aren’t necessarily cheaper to build. You need bigger facilities, and there are square-cube laws, you need to transfer forces over larger distances. Yes, the same is sort of true for aircraft, but if scaling up means more of the fuel can go in the wings, then square-cube laws don’t apply the same way.
Using hydrogen isn’t really a safety problem, but it is a regulation and PR problem.
No matter what the cost of airships is, they’re obviously better when you want duration or volume than when you want ton-miles. So you target the applications that make more sense first, and then if that works out well, you can think about other applications and have more data to evaluate them. Eli does not think this way. He goes straight to “let’s build a million huge cargo airships!!!” and he also doesn’t know shit about aircraft design, which is a deep and multidisciplinary field with extensive research into it. So, why would people take him seriously?
Aircraft costs per ton-mile are variable, but here is a report from American Airlines showing $0.33/ton-mile in 2018.
I haven’t investigated this, but there is a long essay from Eli Dourado here that is bullish on the concept.