A new sailing record was set recently, which didn't _quite_ beat 40 days - it took them 40 days and almost 11 hours.
If you've ever seen a SailGP boat flying up out of the water on their hydrofoils and doing 100kmh - imagine a 32m long 26m wide ocean going trimaran doing the same thing in a non stop circumnavigation of the globe. I think they _averaged_ 27knots or 50kmh!
And when the world was still flooded with money and the music was awesome (so 2004), Jeremy Clarkson did a series about inventions, one of them being the jet plane, and he flew commercial around the world in 120 hours: https://www.youtube.com/watch?v=o8D_UzMhjH8
> Finally, can it be flown legally? Most of the trajectory can pass over the oceans, but skipping land completely would take too much of a detour, and likely be incompatible with prevailing winds. Although the political climate may be hostile, it is still legal to fly civil craft over other countries.
This is an interesting article from a couple of days ago about tracking diy balloons long distance: https://spectrum.ieee.org/explore-stratosphere-diy-pico-ball.... Given the tracker can be built for $14 it might be worth it to test a version with just the custom hydrogen enclosure and tracker and see how far it gets.
Hydrogen containment: you might want to look at topping up hydrogen along the way. Have a small compartment inside the gas bag with lithium shavings and a small servo that can release water into this compartment.
You'll get about 1/15-th of the lithium+water mass as hydrogen. So if you want to replenish 1 m^3 of hydrogen at STP (or around 1/8-th of the gas bag volume), you'll need around 600 grams of reagents.
It actually doesn't even have to be a servo. Just have a water container that slowly releases water through a capillary tube/wick into the gas bag, "moisturizing" the gas inside.
Lithium will then scavenge all the moisture from the gas inside the bag, releasing hydrogen in the process.
Hmmm. If, rather than flying close to sea level, you flew at high altitude (above commercial airliners), and kept it relatively small, I suspect that you could do this and no one would notice unless you told them.
Though at high altitudes the winds are such that it would be less of an airship and more of a steerable balloon.
At really high altitudes air density goes down quickly; this is good for planes but bad for airships because payloads are reduced. Plus, as you say, winds are really really strong: over 200 km/h. https://earth.nullschool.net/#current/wind/isobaric/250hPa/o...
I have seen many high altitude airship studies trying to hover around, but none have been viable in the end. To go around the world it seems better to just float, as in the comment above: https://news.ycombinator.com/item?id=46881679.
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[ 3.1 ms ] story [ 33.6 ms ] threadPCAAD: Too Microsoftie.
Also FYI the link to "Aves Æternæ" is broken.
A new sailing record was set recently, which didn't _quite_ beat 40 days - it took them 40 days and almost 11 hours.
If you've ever seen a SailGP boat flying up out of the water on their hydrofoils and doing 100kmh - imagine a 32m long 26m wide ocean going trimaran doing the same thing in a non stop circumnavigation of the globe. I think they _averaged_ 27knots or 50kmh!
https://youtu.be/ffqhFyaCUFA
If you _haven't_ seen the SailGP boats and are curious, here's somewhere to start: https://youtu.be/BQWOoP-Iwn8
> Finally, can it be flown legally? Most of the trajectory can pass over the oceans, but skipping land completely would take too much of a detour, and likely be incompatible with prevailing winds. Although the political climate may be hostile, it is still legal to fly civil craft over other countries.
You'll get about 1/15-th of the lithium+water mass as hydrogen. So if you want to replenish 1 m^3 of hydrogen at STP (or around 1/8-th of the gas bag volume), you'll need around 600 grams of reagents.
Lithium will then scavenge all the moisture from the gas inside the bag, releasing hydrogen in the process.
Though at high altitudes the winds are such that it would be less of an airship and more of a steerable balloon.
I have seen many high altitude airship studies trying to hover around, but none have been viable in the end. To go around the world it seems better to just float, as in the comment above: https://news.ycombinator.com/item?id=46881679.