Airship Question

Azardin

Here is my question. Say all the requisite technology and infrastructure exist to build an operate (rigid hulled) airships in the 1870's. Given a standard steam engine of the time, the like of which they might put onto a ocean going ship, what would the top speed likely be?

Also, assume ideal conditions (safe flying conditions, fuel aplenty, etc.), as if I know the maximum possible under controlled conditions, I can likely extrapolate well enough from there.

Thoughts I had that might affect the performance:

Mass of the airship, as the engines would have to provide a steady force (or near steady) to provide the needed acceleration to give it motion. The more massive, the greater amount of kinetic energy needed to over come its rest state, and then to accelerate it and maintain its velocity.

More historical thoughts would be the type of engine, power of the engine, etc.

So given the above, what might you think a reasonable top speed would be?
 

David S Poepoe

Banned
I think a problem is that the single or double expansion steam engine, the type used at sea, would be fairly heavy for an 1870s airship. I think you should look at the historical airships that were test flown during this period. One problem would be the use of hydrogen as lifting gas. In the Forstchen's Lost Regiment series (sort of a ISOT) the main characters did build airships with caloric engines, so the Sterling Engine may be one route to go.

I don't suspect the speed will be very fast. Even von Zeppelin's first airships couldn't make headway in a strong wind.
 

zoomar

David S Poepoe said:
I think a problem is that the single or double expansion steam engine, the type used at sea, would be fairly heavy for an 1870s airship. I think you should look at the historical airships that were test flown during this period. One problem would be the use of hydrogen as lifting gas. In the Forstchen's Lost Regiment series (sort of a ISOT) the main characters did build airships with caloric engines, so the Sterling Engine may be one route to go.

I don't suspect the speed will be very fast. Even von Zeppelin's first airships couldn't make headway in a strong wind.
Click to expand...

I concur with the observations about power plants, and mixing coal-fired steam engines with hydrogen. Also, in the 1870's light duraluminum alloys would not be readily available, so if you are wanting a rigid frame it would likely be made of wood or steel, both heavier than alluminum alloys. Also, even given the availablility of a suitable powerplant, you'd have to factor in at least 15 years of research and development to come up with a truly efficient rigid airship, meanining that initial research would have had to begin in the 1850's.

But assuming all that, I would imagine 35-40 mph tops, with a maximum ceiling of less than 3000 feet. Such a ship would need to be flown in a manner which took into account the strength and direction of prevailing winds in addition to its own motive power, meaning schedules would be hard to keep and travel routes could never be fixed. Heck, even the big German commercial rigids of the 1930's, capable of 70-75 mph, did not adhere to rigid schedules or routes, but adjusted them to suit meterological conditions.

You might want to supplement powerplants by using the airfoil gliding principle, whereby forward motion is obtained by shifting internal weights and valving gas, causing an unpowered ship to glide forward thru the atmosphere in an undulating up-and-down manner. There are popular accounts that such unpowered airfoil airship was tested in scale model form in the 1860's. This would be strictly a fair-weather and short range option, however, and steering would be tricky. Plus, it lacks that certain steampunk excitement.
 

Abdul Hadi Pasha

Banned
I don't think this is going to work. Coal-fired steam engine + giant bags of hydrogen gas = a reliable disappointment (= boom).

Even if you managed to overcome this, the output to weight of an 1870s steam engine is not great, so you're probably not going to have enough power to really move except in a dead calm, and the range would be terrible.

On the other hand, Zeppelins used Maybach engines, which first came out in the later 1870s, so they are available, although it sounds like you're looking for something more traditionally steampunk.

Without light-weight aluminum, you're stuck with wood, which sets some sructural limitations and is heavier. I don't know much about metalurgy or its history, but aluminum was incredibly expensive in the 1870s - like more than silver - and I'm not sure how lightweight it could be forged at that point.

Azardin said:
Here is my question. Say all the requisite technology and infrastructure exist to build an operate (rigid hulled) airships in the 1870's. Given a standard steam engine of the time, the like of which they might put onto a ocean going ship, what would the top speed likely be?

Also, assume ideal conditions (safe flying conditions, fuel aplenty, etc.), as if I know the maximum possible under controlled conditions, I can likely extrapolate well enough from there.

Thoughts I had that might affect the performance:

Mass of the airship, as the engines would have to provide a steady force (or near steady) to provide the needed acceleration to give it motion. The more massive, the greater amount of kinetic energy needed to over come its rest state, and then to accelerate it and maintain its velocity.

More historical thoughts would be the type of engine, power of the engine, etc.

So given the above, what might you think a reasonable top speed would be?
Click to expand...
 

Azardin

Thanks guys. Its for the story I'm writing with my fiancee, so there are few fantastic elements involved to handwave some of the issues.

Again, thanks for the references, I think I can do some further research to clear up any other questions. And it looks like my guess of 'an attack speed of 30 knots' wasn't all that far fetched, though likely I might be lowering that some.
 

Sachyriel

Banned
Maybe with more investigation into magnetic fields they can use magnetic propellers and helicopter-style lifts to aid the Helium/hydrogen. Then they might be more aerodynamic. Then, with speeds going beyond the speed of sound with rockets from research into explosives.

This is just an outline, so you may add, detract or just 'shoot me down'.
 
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