WI: Saharan Airships

So I was thinking about zeppelins the other day (something that seems to be par for the course on this site), and I got an idea that may or may not be confirmation of my insanity... Lemme know what you guys think.

We all know about the "Mediterranean economy", right? The Mediterranean was such a hotbed of commerce because it was relatively easy for people who lived along its shore to conduct trade with any other group along the coast, as long as they had decent boats.

What if the same thing could happen in the Sahara, but with primitive airships?

Think about it... Western/Subsaharan Africa has always had stuff that Europe and the Middle East have wanted. North Africa has a long history of being a waypoint for exotic African goods. Trade caravans have always criss-crossed the Sahara, carrying salt, gold, spices, ivory, precious woods, slaves, etc.

So what if some enterprising North African Arab, or a Berber, or a scholar in the Mali Empire, or even a North African Roman, or a Carthaginian, or a Phoenician (timeframe doesn't really matter, as long as it's pre-industrialization, pre-colonial, etc.) ends up making the same observations about buoyancy as the Montgolfier brothers, and cobbles together a hot air balloon? Let's say the idea overcomes the necessary hurdles and is gradually fine-tuned (improving elevation control, steering, etc.)... How long is it before some merchant gets a hold of it and decides it would be GREAT for transporting spices from the Bight of Benin to Egypt, or salt from Senegal to Tripoli, or gold from Mali to Cordoba WITHOUT the liabilities that come with long caravans, WITHOUT having to sail around the coast of the Maghreb, and possibly reducing travel time to boot?

Could we eventually see airships, buoyed by hot air (the fuel could be animal dung), turning the Sahara into a "Mediterranean of sand", crossing the desert with their precious cargos, stopping at oases like islands, supporting wealthy mercantile states and empires around the desert's perimeter? Or is it just too unlikely, or dangerous (the khamsin comes to mind as a danger, like a storm on the sea)?

So, what do you think? Am I crazy, or could this actually work?
 
In a hot air balloon, your navigation course is subject to the fickle vagaries of the wind, and one big worry would be losing the wind and getting stuck in a dead spot.

Also, hostile Tuareg clans might take potshots at you if you're flying too low.:D
 
In a hot air balloon, your navigation course is subject to the fickle vagaries of the wind, and one big worry would be losing the wind and getting stuck in a dead spot.

Also, hostile Tuareg clans might take potshots at you if you're flying too low.:D

Don't the same risks apply to travelling by sea, though?

Also, I was having nerd-tastic visions of the Tuaregs monopolizing the airship business and becoming "nomads of the sky" so to speak :D
 
Well you'd need some sort of propulsion system to get around the aforementioned wind problem, so maybe some sort of manual propeller system that could be used when the wind died down.

Ok, now I'm envisioning a small Airship with big sails on the side and handcranked propellers in the back. :D
 
It's difficult for me to explain, but on the sea, you can steer a ship in a different direction from that in which the wind is blowing. You can tack in and out of the wind since your vessel is "anchored" by the water.

Suspended in the air, a hot air balloon can't do the same. It literally goes where the wind takes it and you will have much difficulty steering. I'm sorry for the shitty explanation, but I;ll try to elaborate when my mind is less scrambled. Can't think straight atm.
 
Wouldn't sand cause problems too?
I'm not a mechanic by any means. But I know that in a sandstorm could get into the fans, engine and what not. That can cause headaches of major proportions.
 
Wouldn't sand cause problems too.
I'm not a mechanic by any means. But I know that in a sandstorm could get into the fans, engine and what not. That can cause headaches of major proportions.

And salt spray causes problems for ships on the sea, and desert caravans deal with sand through strict hygiene regimens. It's just a matter of proper maintenance.
 
Unless the airships stop at oasis to resupply their water, they'll be forced to fly around with a lot of water, which is quite dense/heavy to the point that 20th century zeppelins used water as ballast. If that's the case, it might be difficulty to keep the merchant operation profitable as you''ll need quite a bit of water to keep the crew hydrated, and that could take up valuable lift capacity otherwise allocated to precious cargoes.

But I still think the main problem will be steering unless a plausible propulsion mechanism can be devised.
 

Delvestius

Banned
In a hot air balloon, your navigation course is subject to the fickle vagaries of the wind, and one big worry would be losing the wind and getting stuck in a dead spot.

Also, hostile Tuareg clans might take potshots at you if you're flying too low.:D

like Tusken Raiders!
 
The question I'd ask is whether any of the sub-Saharan civilisations actually had the resources to build these ships, especially if you want big ones that cargo and slaves can be transported in. Isn't the ability to smelt iron a minimum condition here?
 
The question I'd ask is whether any of the sub-Saharan civilisations actually had the resources to build these ships, especially if you want big ones that cargo and slaves can be transported in. Isn't the ability to smelt iron a minimum condition here?

Sub-Saharan Africans *did* have iron smelting. Why do so many people assume they didn't? West Africans discovered it independently with the Nok culture of Nigeria and the Bantu expansions spread it south throughout the continent, while East Africans adopted it from their close contacts with Egypt and the Near East.

In any case, this thread is referring to North Africa and the Sahel region, which were well-integrated into the trade routes of the Islamic World by the Middle Ages. Do you really think that Malians would have adopted Islam and Arabic script without picking up basic concepts like iron forging?
 

mowque

Banned
It is far easier to walk then set up an elaborate system of hot air balloons. How many pre-industrialztion hot air balloon transport routes can you think of?
 
Well you'd need some sort of propulsion system to get around the aforementioned wind problem, so maybe some sort of manual propeller system that could be used when the wind died down.

Ok, now I'm envisioning a small Airship with big sails on the side and handcranked propellers in the back. :D

What you're looking for is Heron of Alexandria's steam turbine, of course wether your hot air dirigible could lift enough fuel, water and cargo to get anywhere and make a profit is another question.
 
What you're looking for is Heron of Alexandria's steam turbine, of course wether your hot air dirigible could lift enough fuel, water and cargo to get anywhere and make a profit is another question.

Are you serious about Heron of Alexandria? His inventions were not going to be brought into use, as they would have no practical applications due to slave labor being more prevalent and cheaper. His creations are just not going to spread.
 
If by airships you mean, independent aircraft propelling themselves in the air, forget it before the Industrial Age.

At that, airships were scarcely practical until the invention of the internal combustion engine, the development of high-strength aluminum alloys, and hydrogen as a lift gas. (Actually hydrogen was available long before the other two).

One problem with incremental development of airships from "air rafts" or the like is that they have to have the power (and efficient propellers, but I could by that Classical era people could make good props, if they only had a power plant) to fight contrary winds, which tend to be in a certain speed range, and then to have the structural strength to hold up while undertaking such maneuvers. So while one could make an airship that goes half the speed of say the Graf Zeppelin in some combination structurally lighter or of less efficient materials because halving the airspeed reduces the forces by a factor of four, and its power requirement is reduced by a factor of eight, so a much less efficient or heavier engine could get the job done, such a craft would be almost as much at the mercy of the winds as a free balloon would be.

Meanwhile, if you are trying to lift useful loads with hot air instead of hydrogen, lotsa luck. The less efficient your lift gas is, the bigger the gasbag has to be. Not only is it that much more of a huge sail to catch winds, it is also much greater in area, and that area is weight--whatever cloth you are using. So the amount of lift left over for payload is that much less, and meanwhile the balloon is subject to even greater wind forces.

You can't really have suitable materials, or engines, or lift gases, until you have an industrial civilization.

Now I have mused on the what-ifs of some other planet where the atmosphere is much denser though still breathable, and wondered whether one could have human-propelled airships there on a Classical or even say Viking level of technology. The idea of Legionaries or Nordic raiders flying around in airships is certainly appealing to me! But I also had to consider, the denser the air, the easier it is to make winged flight work too, so as OTL on Earth they might wind up bypassing airships for airplanes, albeit again on a remarkably low tech level!

Finally to save the concept as best I can, I have also wondered about the possibilities of using balloons to ease the task of hauling large weights around. The idea here is, you aren't really free-flying, the total weight involved is greater than the lift available, but the lift from a balloon lightens the load on a cart, a sledge, or say a camel caravan. The system is such that the whole thing is still firmly anchored to the ground and so motion is by traction, but it might be possible for a given number of horses, or camels, or human bearers, or whatever, to to haul a greater load.

Many problems come to mind. For one thing as I say, good lift gases like hydrogen (forget helium among pre-industrial people, the process of refining it out of natural gas sources is very demanding, and there are few natural sources known in the world still yet--though one of them now known, I believe, is in Algeria--but forget it, it would take 20th century tech to extract it) are hard to come by--hydrogen of course has its hazards anyway, and good gas retention materials are also difficult to manage. Hot air has its proponents and it has certain advantages. But one of them is not having a good concentration of lift!

Another problem might actually be solved by moving over deserts and help explain why these things aren't just used everywhere, not just in the desert--obviously if you have a bunch of balloons lifting most but not all of the weight of a cart or caravan or whatever, there is a jungle of lines from the semi-lifted weights on the ground to the balloons. These would surely get tangled in trees and the like in any normally habitable terrain. But this might not be a problem in the desert! So score one for balloon caravans!

Then there is the wind; contrary winds on a balloon capable of lifting a significant load will be a problem. This is where hot air comes in handy; you might simply pull the cord on the valve and let the hot air out, then raise up the balloon again when the winds are more favorable. And a favorable wind might help speed the journey along.

But then there is the other problem of hot air--you have to feed it fuel all the time. I suspect the weight of suitable fuels would be large compared to any possible lightening of the caravan.

So on the whole I doubt this approach can work, and certainly if it could there have been plenty of opportunities for someone to try it.
 
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