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The OP article suggests airships would be on par with conventional shipping freight for time. But in terms of capacity it makes an excellent point: > Cargo air
by h0l0cube 5y ago
The OP article suggests airships would be on par with conventional shipping freight for time. But in terms of capacity it makes an excellent point:
> Cargo airships would need to be big—bigger than the Hindenburg. Airships are blessed and cursed with a square-cube law: the drag of the airship, which is proportional to its cross-sectional area, scales with length squared, but the volume of lifting gas, and thus the gross lift, scales with length to the third power. Therefore, the lift-to-drag ratio, a critical parameter in aircraft performance, gets better as the airship gets bigger.
- 8note 5y agoShouldn't it scale linearly with length? It's basically a cylinder, who's volume is heightPiradius^2. Unless you're also making it wider and taller, it's not a cubed growth
- h0l0cube 5y agoThe way I read it, is that drag increases ^2 for length, but because volume increases lift for airships (as opposed to other aircraft) you get this ^3 increase in lift by increasing length. So airship economy increases with size, as opposed to an airplane. For the square-cube law, a cursory wiki search yields: > The square–cube law can be stated as follows: > When an object undergoes a proportional increase in size, its new surface area is proportional to the square of the multiplier and its new volume is proportional to the cube of the multiplier. https://en.wikipedia.org/wiki/Square%E2%80%93cube_law https://en.wikipedia.org/wiki/Square%E2%80%93cube_law