[tshiggins]

Originally Posted by Daigoro

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How about-
Question 43
What is the state of flying technology? It's 8 years after OTL's flight of the Wright Bros at Kitty Hawk. Do we have prop-driven planes, gliders, ornithopters, personal parachutes, helicopters, rockets or jets? What are the limits of airship design?

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Powerful internal-combustion engines are key to winged flight, but if a setting has internal combustion, then it's not steampunk, any longer.

It may be dieselpunk, but steam engines gave way to internal combustion because internal combustion is so much more powerful, for any given mass of engine.

While liquid petrochemicals can be made from petrol coral, the assumption is that it's just not economical to do so. Petrol coral is processed into liquid hydrocarbons, but only to create lubricants, or very specialized applications. I think this should be expensive enough that most people travel by some sort of mass transportation -- trains, or airships, or riverboats or ocean steamers -- because of lubricant costs.

Local travel and transportation would rely on delivery companies that use steam trucks/lorries, streetcars, or bicycle technology (including cargo bikes and bicycle rickshaws), although a horse-drawn carriage remains a favorite for lots of reasons.

The main exception in this setting would be the presence of large amounts of hydrogen sulfide gas, which is a bit of a game-changer. However, that's heavier than air, very poisonous, corrosive, flammable, and explosive. The slurries -- a great idea, by the way -- is the term used for the lung disease caused by prolonged exposure to the trace amounts of hydrogen sulfide that make it through the gas-masks that petrol-miners must wear.

(I perceive that most petrol coral gets used in fist-sized chunks, the same as coal. However, it can get ground down into an oily, fine powder that tends to clump. Aerosolized, this stuff is bad to breathe, too, and results in "slurries" that look a lot like black lung disease. Still, I'd think "petrol powder" would be the "premium" fuel of choice in the hoppers for smaller vehicles, because it minimizes the amount of wasted space.)

That said, the fact that hydrogen sulfide is so energy-dense, and can be pressurized in a way that tar coral can't, means it's the primary choice for uses already seen as rather risky, or for which no other means really exists.

So, airships use high-efficiency Stirling engines (with military research into Stoddard engines ongoing) fueled by pressurized hydrogen sulfide, the fumes from which get vented to the outside of the vehicle. Ground-crews probably also wear gas-masks until the engines get shut down, and maintenance crews probably have them handy.

I'd think most airships go for size and power, rather than speed, and good airship pilots have a feel for finding helpful winds. Most passenger craft handle up to 200 (well-heeled) passengers in sumptuous comfort, during transatlantic flights that take up to four days, or transpacific flights that can take up to 10 days (New Orleans to Shimla, by direct flight of the famous Himalaya Clipper). Large cargo airships carry up to 40 tons of high-value cargo (luxury items are the usual manifest), and can deliver it from point-to-point, without multiple changes in modes (truck to train or riverboat, then to ship, back to train or riverboat, back to truck for final delivery).

Cargo airships take deliveries from trucks or trains, transport the goods in a tenth the time of surface transport, and either drop it directly where its needed, or hand it off to the recipients' vehicles. This costs a lot of money, which means only high-end goods or commodities make the trip -- which, in turn, makes them prime targets for air pirates. Passenger liners, on the other hand, are usually pretty safe. Usually.

As a comparison, a single large C-130 cargo plane with an extended fuselage can carry up to 20 tons, by itself, and make the trip in a quarter of the time, including stops to refuel, if needed. A C-5B Galaxy carries up to 190 tons, and takes about as long as a C-130. That's what propellers driven by internal combustion engines do, for you. Jets are even faster, but are also fuel-hogs.

(Also note: high winds are a problem. If a day is even slightly blustery, airships don't bother to try to land. They just remain at altitude and ride it out until conditions calm. Stirling engines are highly efficient, but not spectacularly powerful, which is why most dirigibles have at least six of them, and large cargo airships may have up to 12.)

Exceptions to the "size over speed" rule would be for military pursuit dirigibles, designed specifically to destroy other airships. These feature small crews on dirigibles with multiple powerful engines, and turret-mounted weapons (Maxim guns are favorites, since armoring dirigibles is counter-productive) mostly slung beneath.

The Black Manta's airship is probably based on military pursuit dirigibles, with the additional refinement of a fairly aerodynamic lifting-body design. Assuming the airship doesn't get destroyed by those charged with hunting her down, the military will be highly interested in its design (and His Majesty's Royal Navy may already have savants knocking around some ideas along those lines).

Most modern airships follow the "Hindenberg" model of placing the bulk of the crew, as well as cargo and/or passengers, within the airframe rather than in a gondola slung beneath. However, most dirigibles have at least a small gondola, used to direct landing operations, and many of the older models still fly, as well.

Following a couple of very public accidents, most countries forbid the use of hydrogen as a lifting gas. This usually presents no problems, as the widespread distribution of petrol coral mining and processing means helium is readily available as a by-product. That said, some particularly crazed science-pirates have been known to use hydrogen, which has better lifting power, as compared to the same mass of helium. Usually, those villains die spectacularly.

Another use of hydrogen sulfide appears in military submersibles, and the service is considered highly hazardous. However, even military submersibles spend most of their time on the surface, and the engines vent the fumes to the outside of the vessel. Once the vehicle submerges, it switches to battery operations, although some successful experiments have seen the use of main engines, with venting through snorkels at periscope depth.

Still, it remains a very dangerous duty, and submariners are both rare and well-paid. There is no such thing as "non-combat pay" for military submersible sailors.

Addendum: The Himalaya Clipper charges 100 pounds sterling for each of the 150 "Standard Fare" tickets. This comes with double-occupancy in a well-appointed pullman-style compartment, cleaned daily. The 40 tickets for "Luxury Class" include a single-occupancy compartment, and cost 200 pounds sterling, for the 10-day trip. The 10 "First Class" accommodations have single-occupancy compartments twice the size of the other accommodations, 24 hour service by hot-and-cold running stewards, two bathrooms for use by First Class passengers, only, and guarantee at least one dinner at the commander's table. Those cost 500 pounds sterling.

Airship travel is for the wealthy, or for those with high-end government or corporate expense accounts. Everybody else takes a steamer and trains, and the trips take two to four times as long.