40d:Windmill

A windmill is a machine component that provides power via wind on the surface of a fortress map. Currently, a windmill provides 40 units of power (sometimes less, apparently depending upon the available wind) and requires 4 pieces of wood. Using multiple windmills increases the power production.

Construction

To get some useful power out of a windmill:

1. Build the windmill.
2. Excavate a path under it to the center of its base, 1 z-level down.
3. Add a vertical axle, gear assembly or machine there, which will have power. A floor between the windmill and this is fine.
4. Gear assemblies can be used to transport the power back to the surface, if desired.

In rare cases, building a gear assembly before the windmill will not connect the gear assembly to the windmill. Simply reconstruct the gear assembly to connect it.

Windmill tower

The "windmill tower" option is useful if you can't dig below your windmill (if, for example, there is a room or underground river there). This option is also often more power-efficient, as it often eliminates the need to transfer power between z-levels.

1. Build a 3×3 platform out of floors one level above the ground floor.
2. Build the windmill on top of the platform.
3. Directly beneath the windmill, on the ground floor, build a gear assembly.
4. Connect this assembly to horizontal axles, and power your machines. No digging required!

A windmill can also be built directly on top of a gear assembly, obviating the need for a platform. However, if switched off via lever, a windmill constructed in this fashion has a tendency to collapse.

How to transfer power between z-levels

After you have a gear assembly in place on a level, you need to switch to the level above it and remove the floor between its tile and the tile above it. Then, build a vertical axle or a gear assembly above the first gear assembly.

Construction Example

1. A Pond To Drain
≈........
≈≈≈......
≈≈≈......
≈≈≈......
≈........
2. Add Some walls to control output, and an access ramp (leaving access is a good idea)

≈.....▲..
≈≈≈○.○═══
≈≈≈......
≈≈≈○═════
≈........

3. add 3 floor tiles above the gap, then build your windmill

......▼..
...+.++++
....+++.. (← here)
...++++++
.........

4. build a lever and gear assembly, then link your lever to the gear

≈...ò.▲..
≈≈≈○.○═══
≈≈≈..☼...
≈≈≈○═════
≈........

5. Finally, throw the lever, add your screw pump and the final wall section

≈...ó.▲..
≈≈≈○═════
≈≈≈%%☼...
≈≈≈○═════
≈........

Alternatives

• Skip the lever and gear and power the pump directly, "always on".
• The "Blowback" wall method:

≈...ó.▲..
≈≈≈○═════
≈≈≈%%☼...
≈≈≈○.╔═══
≈..╚═╝...

This allows water to flow past the pump when the pump is off, allowing for two pumps to use a single set of walls to contain the flowing water, with the direction based on which pump is on. It also allows for maintenance access from the pipe, at the cost of 3 extra wall sections and one extra floor.