Other Jimness > Cinder Spires Books
Sails?
Yeratel:
I have the mental picture that an airship acts much like a submarine, in a sea of moving air. The lift and trim crystals are like ballast tanks, moving the ship up and down, where it can take advantage of different air currents or aether currents at different altitudes. Without the aetheric webbing to provide propulsion, the ship is carried like a cork on the air currents, and it's streamlined shape means it actually moves a little slower than the air current, unless it extends its sails to provide more surface area and get up to the speed of the air. And with regular sails, it can only move in the direction of the airflow. With the aether silk sails extended, actual thrust is provided, which can move the ship in any direction, including against the flow of the air.
Was there not also mention made of ships with steam engines? Perhaps with propellers like a dirigible, or was that just for running the windlass barges that traveled up and down the spire?
Quantus:
--- Quote from: Yeratel on October 26, 2015, 09:27:16 PM ---Was there not also mention made of ships with steam engines? Perhaps with propellers like a dirigible, or was that just for running the windlass barges that traveled up and down the spire?
--- End quote ---
There was, they are the more popular choice than wind for a backup engine. They use "steam-driven propellers and the new screw-like turbines." But they are both heavier and louder than wind power. Not to mention the fact that a pile of canvas very rarely explodes...
knnn:
--- Quote from: Quantus on October 26, 2015, 09:05:47 PM ---The difference, I think, is that the trim and Lift crystals are not actual thrusters, they are anti-gravity pumps. They can tilt a vessel by applying less lift to a port-side trim crystal than the starbard-side, but the forces are always acting only in the vertical plane in direct opposition of natural gravity, and so they cant actually apply force in a horozontal direction. I think the horozontal rotation (ie "Yaw", for those that dont want to look it up like I had to :p) comes from teh interplay of the "Control planes" (wings) and the asymetric pulling from the various Etheric Webs.
--- End quote ---
I think I agree with this, though I personally don't think "control planes" are enough given the reasons I mentioned above.
FWIW, you've got the following quote:
--- Quote ---"Grimm saw the enemy ship sturggling to stabilize itself with it's trim crystals alone - a tricky proposition without enough forward momentum to allow the more responsive manuevering planes to assist with the task".
--- End quote ---
This directly confirms that the "manuevering planes" are what counts.
But then you've got the following:
(during final battle with Itsaca, one set of web destroyed, other reefed, and one set of trim crystals burned out):
--- Quote ---"Hard to port at flank speed, Mister Kettle! Stay ahead of her turn!"
--- End quote ---
Basically, Predator is managing to make a circle around Itsaca (and keeping ahead of the battlecruisers' steam-powered turn) despite having no sails out, no web, and only half her crystals working.... I don't think I can explain it unless we're saying there was enough residual speed to do this. Even then. how are they going to turn? I can't imagine that the control planes are big enough to do anything -- wind resistance is simply not going to be enough.
Maredudd:
Hi Folks!
I looked up "Trim" as it relates to aeronautics and based on what I saw, are we certain that the Trim Crystals do not provide the same function for Jim's airships as they do for aircraft today?
You want to go in a particular direction and set the trim crystals and the produce the forces necessary in the airship to move it to the desired orientation, Not that they provide no motive force though so whether you are using the etheric web or the sails, its business as usual. Technically this could compensate for the what is missing when compared to a surface ship.
Shecky:
--- Quote from: Quantus on October 26, 2015, 09:05:47 PM ---The difference, I think, is that the trim and Lift crystals are not actual thrusters, they are anti-gravity pumps. They can tilt a vessel by applying less lift to a port-side trim crystal than the starbard-side, but the forces are always acting only in the vertical plane in direct opposition of natural gravity, and so they cant actually apply force in a horozontal direction. I think the horozontal rotation (ie "Yaw", for those that dont want to look it up like I had to :p) comes from teh interplay of the "Control planes" (wings) and the asymetric pulling from the various Etheric Webs.
--- End quote ---
That's if you're assuming that lift and trim crystals work in precisely the same manner, which I'm not. But you're certainly correct to point out the control planes; while they wouldn't provide the same order of magnitude of effect as a keel in a denser medium, there'd certainly be torque available.
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