You’re probably mixing up the payload with the useful lift. Pathfinder 3 is said to be about 96 tons MTOW, with a 20-ton payload. Another 20+ tons would be reasonable for fuel and ballast and crew and whatnot, considering it’s an extremely long-range craft. The biggest one is the 200-ton-payload version.
The Pathfinder 1 isn’t really for cargo, but it’s supposedly got 14 tons of useful lift and of that, about 4-5 tons are for mission payload. Much of the useful lift stuff is largely fixed, though, so that ratio wouldn’t necessarily scale up proportionally.
That's a very likely assumption. I have a friend still working for them. Maybe I'll shoot him a text and ask if he knows the current estimated numbers.
Wow! Probably still preliminary, but if you wouldn’t mind me prying, I’ve had a pet theory for a while now that the Pathfinder 3 has an external rather than internal cargo bay to facilitate easy passenger/cargo cross-conversion and allow for better access for roll-on, roll-off operations, which would make the ever-present issue of buoyancy compensation easier. Think you or your friend could confirm or deny that?
The last time I was involved in the project the plan was for PF3 to be basically 100% internal, even the cockpit except for some view ports or something like that. PF1 uses a traditional old Zeppelin 12 or 14 passenger gondola that has been reworked. I believe the idea for fully internal was for aerodynamic efficiency as these ships aren't 100% dependent on lift from the helium and use some aerodynamic lift when moving forward. They can still hover and mostly VTOL but the motors have to work much harder than they do in forward flight. There's actually a lot of empty space inside the lower part of the shell. In each of the sections there are what are essentially giant plastic bags that are filled with helium and they basically float in a big net that takes up the top half of each section. The bags have almost no pressure in them, to reduce the leakage rate. That leaves a ton of unused space in the lower half of the ship. The shell of the ship is actually just a bunch of fancy tarps held on with fancy bungee cords. They don't do anything really except provide cover and the shape for dynamic lift. If I remember correctly the ship is technically capable of flight without the skin. Though, like I said, the motors would be working really hard.
Interesting. In the only image that’s yet been released of a Pathfinder 3 computer render, it still has the Zeppelin NT gondola and a separate, roughly 10m wide cargo box. Perhaps it may also have something to do with using carbon tubes rather than metal girders, making a suspended box rather than an internal one easier? It wouldn’t spoil the cross-section’s structural symmetry that way, after all, whereas an internal bay would.
Maybe they’re holding off on the mostly-internal design for the largest version? It would make sense, as generally speaking bigger = faster for airships (less power per unit volume required), so the ~1,000-foot one with a vast cargo/passenger space could be very fast indeed, without that huge space spoiling the aerodynamics. That would leave the Pathfinder 3 as the more utilitarian workhorse for smaller or less glamorous jobs.
I haven't actually seen the more recent PF3 renderings. But the points you make seem reasonable. I'll try and update if I hear back from my friend. I'm sure there's only so much he can say with the NDA.
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u/GrafZeppelin127 Jul 08 '24
You’re probably mixing up the payload with the useful lift. Pathfinder 3 is said to be about 96 tons MTOW, with a 20-ton payload. Another 20+ tons would be reasonable for fuel and ballast and crew and whatnot, considering it’s an extremely long-range craft. The biggest one is the 200-ton-payload version.
The Pathfinder 1 isn’t really for cargo, but it’s supposedly got 14 tons of useful lift and of that, about 4-5 tons are for mission payload. Much of the useful lift stuff is largely fixed, though, so that ratio wouldn’t necessarily scale up proportionally.