What Would Be Necessary for Airships in the Modern Era

[Scottty]

All they need to do is fire at it for a long period of time with API ammo.

But you won't have a "long period of time" - you'll have as long as it takes for the Kirov to reach you and bomb you to bits.
And that's assuming gravity bombs like the videogame ones. Some kind of air-to-ground missiles instead? Life just got a whole lot shorter for your AA crews.

Stop thinking of it being like an airplane - think of it as more like a frigate or destroyer that floats in the air. Could you sink a navy ship by drilling through it with API ammo? Theoretically, if they were to let you.

 

[S'task]

Actually, there's a simple way to make Airships viable as primary mode of air transit:

Ban jet fuel and other hydrocarbon based fuels.

Without the massive energy density that is aviation fuel and gasoline, there's no way to make an airplane viable. Batteries are to heavy to be effective for long range airplane travel and no other fuel can even begin to approach the power requirements unless we develop a small scale fusion reactor (there's no way they're putting a fission reactor in something that flies... way to dangerous). There's a reason the aviation revolution had to wait until gasoline engines had become a fairly mature technology to really, pardon the pun, take off.

Without aviation fuel, airships actually become a very viable form of mass air transit. With a proper configuration, they can run off solar power (you could line the massive surface area on the top with solar panels) to run the engines and then use either helium or hydrogen for a lifting gas.

So, if you're looking for a way to justify it, just wait a few more years and the greens will get around to it. Or if you want to build a fantasy steampunk world, just have that world lack Oil, which would derail the development of the internal combustion engine and thus dramatically change the way mass transit is done, likely towards the complete dominance of trains and airships.

 

[Morphic Tide]

Ban jet fuel and other hydrocarbon based fuels.

Perhaps have "Peak Oil" be a real thing early enough to make use as aircraft fuel uneconomical? Or fail to descover appropriate refinement in time. Or the aerodynamics of lifting wings take longer to crack causing a better head-start.

I'd be interested in figuring out the "unobtanium" for an envelope material as the starting point, then working out a plausible best-fit. Rigid but not brittle for aerodynamic optimization, high strength to weight ratio to handle weather and sub-atmospheric internal pressure, tolerant of hydrogen fires to prevent a Hindenburg as one ignition point won't set off additional gas-cells...

My first instinct is some peculiar setup of resins and synthetic fibers coming about early, where an extremely primitive composite construction is close enough to ideal to make reduced-pressure gas cells viable while simultaneously saving structural weight over the historic equivalents.

Then further advancements allow continually lower pressures as material science gets a dramatic kick in the balls, all timed such that even when heavier than air flight is figured out it isn't nearly so big a shake-up because the fuel costs would be murder on the airliner ticket and the startup costs for zeppelins have already been amortized.

...More fantastically, a folding zeppelin you pull out with a hydraulic system, automatically re-depressurizing itself in the process, would save a dramatic amount of hangar space, perhaps going so far as to doing a great deal of the work in enabling the old flying aircraft carrier concepts.

 

[Laskar]

I'd be interested in figuring out the "unobtanium" for an envelope material as the starting point, then working out a plausible best-fit. Rigid but not brittle for aerodynamic optimization, high strength to weight ratio to handle weather and sub-atmospheric internal pressure, tolerant of hydrogen fires to prevent a Hindenburg as one ignition point won't set off additional gas-cells...

So, from what I understand, the Hindenburg had internal gas cells that were filled with hydrogen and an outer envelope that could be filled with helium. Any hydrogen that leaked out of the interior gas cells would diffuse in the inert atmosphere of the helium envelope, and any leakage from the helium envelope would be too diffuse to ignite. However, the US was the biggest supplier of helium in the '30s, and we cut off helium shipments to Germany. The Hindenburg ran on 100% hydrogen for its maiden voyage, and we saw the result.

What's to stop alt-history airships from borrowing this design?

 

[Marduk]

Yet this wasn't something the entire British Military could pull off when Zeppelins were dropping bombs on London by the hundreds... are drugged up third-world militiamen with a pickup really that much more powerful than the entire RAF was then?

Funny you mention that, RAF was formed in 1918... By then the Zeppelins were absolutely on their way out, nothing like their best days sometime around 1915.

Do not underestimate the terribleness and unavailability of WW1 era anti air weapons. They even sucked against biplanes after all. The original Browning M2 was invented to help with that afterwards.
The norm were slightly repurposed light artillery cannons and plain WW1 machineguns, and its Germans who were famous for having AAA ahead of the curve then. A ZU-23, compared to that, is not as bad as comparing a T-55 made at the same time to WW1 tanks, but its not that far off either.

The pressure of the lifting gas is usually neutral to atmospheric. Puncture damage will make an airship sink slowly.

In order to get an airship to actually crash, you need to have High Explosive ordnance explode inside the gas bag and basically destroy the airship outright.

Lucky for them, good ol' 23mm autocannons by default use ammo mix of API-T and FRAG-HE-T, sometimes with HEI-T mixed in. And they fire it at a very high rate. Coincidentally the latter, designed to shred a large area of metal skin of CAS aircraft with barely few hits can do it even better to an airship.

Actually, there's a simple way to make Airships viable as primary mode of air transit:

Ban jet fuel and other hydrocarbon based fuels.

Without the massive energy density that is aviation fuel and gasoline, there's no way to make an airplane viable. Batteries are to heavy to be effective for long range airplane travel and no other fuel can even begin to approach the power requirements unless we develop a small scale fusion reactor (there's no way they're putting a fission reactor in something that flies... way to dangerous). There's a reason the aviation revolution had to wait until gasoline engines had become a fairly mature technology to really, pardon the pun, take off.

Though that works only for civilian use by countries run by crazy people.
As the local major power try to not laugh themselves to death, and tell them to enjoy trying to wage war with that against proper aircraft and modern air defenses.

 

[Scottty]

Ban jet fuel and other hydrocarbon based fuels.

And enforce that ban how? Seriously, you and what army?
Given that the people who thumb their noses at said ban will have a better army.

 

[Bassoe]

OK, let's give this a try; the Drone Hive.

Entirely autonomous. Solar-powered, for both operating itself and heating the air which it uses as lifting gas. Can function essentially indefinitely until it needs to return to base to resupply quadcopters, though has to go mostly dormant at night to save its batteries for keeping its gasbag heated. Topside is covered in solar panels, underside in parasite docking for explosive kamikaze quadcopters. Uses inferred and radar to watch the ground and upon detecting the heat of human biometrics or engines, launches quadcopters to get a close enough look for facial recognition. Rules of engagement programmed beforehand, can range from "ID everyone and broadcast their locations back to base so that a fleet of said Drone Hives can track everyone everywhere at all times", "if you see anyone on the kill list or who fires at approaching scouts, kill them" to "everyone in the following area who doesn't have an ID chip must die".

 

[Vargas Fan]

Zeppelins in WW1 were downed by specially developed incendiary rounds as has been mentioned, but it need also be mentioned that for a while, a Zeppelin could outdo aircraft in terms of altitude. Many of the earlier biplanes could not reach the height a Zeppelin could, or could only get near it for a short time.

As has been mentioned though, rigid airships were significantly tougher than normal observation balloons and the later blimps.

Rigid airships though are subject to the stresses of weather conditions, look at the airship Shenandoah for example which was literally torn in two by storm conditions, there were similiar fates that befell the Akron.

 

[Zachowon]

World War 1 also didnt have dedicated Anti Air weapons like we do now that can reach higher then most planes back then could fly