xkcd #3298: Aerospace Flowchart
Title text:
Someday, we will find the problem that goes with this solution.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3298/
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But how do we convince investors to fund huge airship hangars in low density regions? They need adventure pools too, you know?
What about huge underwater submersibles ?Won’t someone think of the captains obsessed with the cleanliness of sheets?
Last month I went on a Zeppelin ride, there are some tasks that airships do well. Tourism tours, long term temporary monitoring, some specific geo surveys and advertising.
There are still airships in operation? I thought it was blimps only
Whoa. Good for you.
And for radio relays. Although that’s more of a balloon job.
I noticed the lack of a ‘Yes’ flow.
I feel like you’re ignoring how cool massive airships are
Can confirm, I went on a Zeppelin flight earlier this summer, can absolutely confirm that it was damn cool.
China: “Hold my blimp.”
I studied aerospace engineering. Can confirm
These are good priorities. We fumbled her so badly
We should do it anyway, just to be sure.
Could we put an airship in Venus’s atmosphere? It seems like it’d be more useful than sending something to the surface, but I know nothing about the engineering involved.
For a short time, maybe. Until it is shred to pieces or dissolved by the atmosphere I would guess. But I’m not an aerospace engineer. :)
No, it’s actually kind of an idea that people have thought about. The upper atmosphere on Venus is a kind of OK environment and because of the thick atmosphere, it’s even easier to float there than on earth. The trouble really starts when the acid clouds begin.
But what if the problem is that you want to be able to hover in one place and lift stuff without having to continuously spend energy on enough thrust to push that weight upwards?
Slap a camera and a bunch of batteries on a balloon and you can easily map large areas without recharging. Great for photogrammetry. You can also carry other instruments onboard.
Lifting stuff with an airship is surprisingly terrible.
Why?
Our old arch nemesis, physics…
The problem is not that you can’t build an airship that can lift say ten tons of cargo.
The problem is what you do when you remove the cargo from the airship.
Without the cargo, the airship will be ten tons light, you would need to make sure you could hold it down against a lifting power of ten tons.
Ok, so let’s just fill it with water on the return journey, easy!
How would you do that in sync with removing cargo, the cargo which probably is a cargo container, and is just disconnected, you can’t just suddenly move ten tonnes of water onboard the airship, it takes time to fill up.
Ok so you get another container with a dummy load to enable a simple connect disconnect at the loading dock, fine that would work, apart from what you would do when the next load arrives, do you just manufacture dummy loads and take them back to the start, how do these get back to the other side where they are needed, and why don’t we use the same method to move the initial cargo?
A few solutions I could think of right off the bat:
- A logistical network so that not every A-B path has to be a net-zero-mass trip, only the nodes - reduces dummy load requirement
- Mass congestion pricing to help balance out the nodes
- Large water bags, send them back empty
- One-way airship travel tourism, brings extra revenue and publicity as a plus
As I always say: Physics knows no favours and no bosses.
Boss wants me to do something that physic doesn’t allow? I laugh at him for his hybris. No, won’t work, because… See first line of this comment.
Ok so you get another container with a dummy load to enable a simple connect disconnect at the loading dock, fine that would work, apart from what you would do when the next load arrives, do you just manufacture dummy loads and take them back to the start, how do these get back to the other side where they are needed, and why don’t we use the same method to move the initial cargo?
If you just have a tank for the water, you could just fill it before unloading.
Then you would need a heavier structure to be able to support twenty tons in total, ten tons need to be supported by the landing gear.
This makes things heavier.
Also, where do you get ten tons of water from, where you at the same time can’t drive a truck?
Only carry liquid cargo, pump out of the cargo tank at the same rate you pump into the water tabk. You’d be able to maintain ten tons to an acceptable margin of error.
Vacuum the lifting gas out of the giant balloon into some storage tanks to compress it and use some smaller balloons as a tiny giant airship to transport the apparatus back?
You need the lifting gas to fill out the envelope and maintain structural integrity, a floppy envelope isn’t amazing at control
how hard would it be to have a big anchor that offsets the weight of a couple cargo containers while it fills a ballast with water?
A winch and cable, a balloon and a comfy basket, enough wine for a weekend. - Sales pitch for my floating AirBnB.
sadly there is no yes line in first triangle of flowchart.
