Hot Air Balloons

I don't know how high zeppelins can go as a practical matter. Theoretically, with no payload at all they should be able to reach a height where the air outside matches the density of the gas inside, so depending on payload mass the actual height will be less. From what I remember Safehold is slightly smaller than Earth. That means air density would fall off more rapidly with altitude. You'd have to run some specific numbers to know if the effect was significant or not.

Believe me, I knew. The zeppelins of first years of World War I could climb up to the 2000 meters, and temporarely - by using enignes and altitude control surfaces - up to 3000-3500.

At the heights they've historically flown though, massed rifle fire from the ground could punch enough holes to cause noticeable leakage (and force them down).

Historically, there was no cases when airship was brought down by rifle fire. Especially by the fire of mid-XIX century rifles.

bullets passing through canvas, mylar, or whatever the gas bag is made of, probably wouldn't spark but I imagine there's still a remote chance of it with each hit.

No, they would not. Even the tracer bullets by themselves would not have a significant chance to ignite the airship. Only the combination of HE and tracer bullets was deadly to them; the HE's ripped the envelope and formed a huge gas leaks, and the traces ignited the resulting hydrogen-air mix.

Father Paityr isn't going to convince anyone flying machines are within the bounds of the Proscriptions, no matter what creative BS he comes up with to support the idea.

Please! The hot air is rising, because the God created it so. There are another gases, that are lighter than air - of course, because God created them so! So, what's wrong with the idea to use the gases to fill the ship and float in air? Flying? Be serious; only Archangels could really fly! Whaty are we talking is a mere floating in air, as ships float in water. And the ships are allowed, of course!

n7axw wrote:Actually what would interest me more than balloons would be heavier than air flight...steam powered airplanes. But we are a way from seeing that.

Don

On the Safehold level of tech, the airships are much more practical solution. The steam airplanes may not really be avalialbe without some electrical-based tech.

This is sort of an interesting thread. All the discussion, IMHO, of powered airships capable of controlled movement is irrelevant to the current arc.
A tethered hot-air observation balloon is within the bounds of the Proscriptions. There is no attempt to go anywhere other than the end of that big rope connecting it to the ground. Heated air is comparable to water flowing downhill so there's no power source argument.
Anyone who saw, or heard about, the towers at Thesmar is gonna say, "Hey, that's a pretty smart idea", with no thought of the Proscriptions being violated.
I'm enjoying the discussions of other types of aircraft, especially the idea of steam powered flight but we all know it ain't gonna happen until the Proscriptions are lifted.

ecortez wrote:Balloons wouldn't be workable as either reconnaissance

They were used for that in REAL history.

ecortez wrote:or offensive platforms because you can't steer them at will, into enemy territory and then back to base, full circle, regardless of wind conditions.

That´s because recon balloons were TETHERED in place, usually well behind friendly lines, but still close enough to enemy lands that altitude combined with good optical gear allowed them too see far into enemy lands.

They were often considered extremely valuable as they provided information that could otherwise only be gained from spies in just the right time and place, which was then drastically slower to be sent "back to base".

ecortez wrote:I don't know how high zeppelins can go as a practical matter.

http://sped2work.tripod.com/zeppelins.html

"To beat the sting of fighter aircraft and increased British anti-aircraft ground defenses the Zeppelin company began to develop a special series of rigid airships called Height Climbers that routinely operated at altitudes above 20,000 feet."

So, 6000m+ is possible. But those height climbers were MUCH less reliable and more dangerous to their own crews than regular ones.
They were essentially totally stripped down, while the "gas bags" were made to expand much more than normal.

ecortez wrote:From what I remember Safehold is slightly smaller than Earth. That means air density would fall off more rapidly with altitude. You'd have to run some specific numbers to know if the effect was significant or not.

It´s far more complicated than that.

It´s perfectly possible, in theory at least, to have a cold, very dense atmosphere that goes quite high around either a small OR large planet with either high OR low gravity.

Some things are far more likely than others, but most combinations are possible.

Also remember that large (solid ) planet does not equate high gravity any more than the opposite.

ecortez wrote:At the heights they've historically flown though, massed rifle fire from the ground could punch enough holes to cause noticeable leakage (and force them down).

Not easily though. And at range and altitude they´re not easy targets either.

ecortez wrote:Hydrogen is potentially explosive but requires a spark; bullets passing through canvas, mylar, or whatever the gas bag is made of, probably wouldn't spark but I imagine there's still a remote chance of it with each hit.

That´s what incendiary ammunition is for.

ecortez wrote:If you can switch to helium that risk goes away but it also lowers your maximum cruising altitude.

Very very unlikely with the limited tech. Hydrogen is relatively easy to produce, helium very VERY much is NOT.

In a discussion i found about alternate history ideas, someone mentioned Stirling engines for Japan in WWII, but the eventual verdict was that even with assistance from a throwback from modern times, getting the helium needed was extremely unlikely.

And that´s WWII real world history in a nation that was among the 10 most advanced in the world at the time.

Dilandu wrote:

n7axw wrote:Actually what would interest me more than balloons would be heavier than air flight...steam powered airplanes. But we are a way from seeing that.

Don

On the Safehold level of tech, the airships are much more practical solution. The steam airplanes may not really be avalialbe without some electrical-based tech.

This doesn't sound likely. As far as airships being more practical, compare how much more readily planes move around. There is a reason that airships were pretty much ecclipsed in our timeline.

Steam is operating without the benefit of electricity now on Safehold. There is no reason to believe they couldn't be appropriately sized to power an airplane.

Don

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Dilandu wrote:

n7axw wrote:Actually what would interest me more than balloons would be heavier than air flight...steam powered airplanes. But we are a way from seeing that.

Don

On the Safehold level of tech, the airships are much more practical solution. The steam airplanes may not really be avalialbe without some electrical-based tech.

Airplanes does not in any way require electrical technology to function, steam or not.

Dilandu wrote:

n7axw wrote:Actually what would interest me more than balloons would be heavier than air flight...steam powered airplanes. But we are a way from seeing that.

Don

On the Safehold level of tech, the airships are much more practical solution. The steam airplanes may not really be avalialbe without some electrical-based tech.

A non-electric (except for FAA-mandated gear) helicopter exists today. I don't think it could be built with safehold tech, though--the fuel is 70% H2O2. It's actually a lot simpler than an ordinary chopper, my impression is that it has less than a dozen moving parts.

They don't need F22's Stringbags will do.

If you are using icus with gasoline you need electric system. With diesel you don't need juice, although you do need a way of starting it. Steam of course needs no juice to run at all.

Don

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Here is a summary of salient facts and links to good sources:

Because of the lift limitations compared to a hydrogen balloon (hot air need 3.5 times the volume for hot air compared to hydrogen), no hot air balloon was ever used in combat.

Hydrogen needs to be in present in air at between 4% (so mix is 96% air) to 75% (so 25% of hydrogen was replaced by air in the balloon envelope for it to be ignited). If it is present in this range it is easily ignited by a stray spark.

Civil War balloons were generally deployed at 1,000 feet and at a distance from a static front. They were generally invulnerable to artillery and small arms fire.

During the Civil War no balloon was shot down.

WW1 balloons had to be deployed further from the front, around 3 miles, and operated at an altitude from 1,000 to 4,000 feet. The main killer of WW1 balloons was the late war fighter with incendiary bullets and/or rockets.

Coal gas from coking operations is primarily hydrogen and available to Safehold now. Field deployable units using acid and iron are well within Safehold tech. The main obstacle is engineering the units to fill the balloons in a reasonable time. The Union Balloon Corps used Navy shipyard workers to design and build their units.

Reference for Civil War use:
http://www.civilwar.org/education/histo ... oogle.com/

Reference for WW1 Balloons
http://www.westernfrontassociation.com/ ... 9v3bJ.dpbs

So hydrogen static balloons could be built on Safehold. It should not violate any church proscription unless mixing metal and acid is proscribed. They could be valuable for artillery spotting and monitoring enemy troop concentrations in fairly static situations.

A steam powered blimp is in the realm of possibility. My guess is that such a machine would be severely range limited due to the lack of a concentrated fuel such as LPG or some distillation of petroleum oil.

Laenole
"All that glitters is not gold"