Steam Engines
Steam Engines are a high-investment, high-output method of generating Engine Power, Energy, or rotational momentum for your Vehicle.
Overview
Steam engines are a versatile engine choice. They can be built either powerful and inefficient, less powerful but very efficient by recycling steam multiple times, or a combination of the two. Steam engines create heat, which can be seen by IR detection, and will leak if any part is destroyed, rendering sections of the engine ineffective. Steam engines don't require an exhaust port, but do require one meter of clearance on the outlet of each piston (unless connected by pipes to another piston). While steam engines primarily create Engine Power, they can also be configured to produce Electric Energy or directly used for propulsion.
Components
All steam components, except for pipes, have a small, medium, and large size. All steam engines will have steam generation and power generation. Some steam engines will have more specialized components, but they are not required to build a working steam engine.
Steam Generation
- Steam Controller - Foundational part of a steam engine. Controls the burn rate of the boilers it's connected to. The small and medium controllers only manage boiler burn rate, but the large steam controller also creates and stores steam.
- Steam Boiler - Boilers burn material and raise pressure in connected pipes, up to a maximum value of 10. Each boiler system needs at least one controller, connected to a column of boiler blocks, which in turn is connected to a pipe. More boilers create more steam for the system. Large steam boilers are unique in that they have more customization options for their boilers. Boilers will initially burn a large quantity of materials to build pressure, after that they will only burn the materials needed to maintain maximum steam pressure (10). All three sizes of boilers create 1,000 steam for every 1 material burned, so there is no difference in efficiency for steam generation between the different sizes, only volume.
- Steam Tank - Stores large amounts of steam. Comes in two sizes, 1m which holds 30,000 steam, and 3m which holds 300,000 steam.
| Part Size | Max Material Burned per Second |
Max Steam Produced per Second |
Steam Capacity |
|---|---|---|---|
| Small Boiler | 0.75 | 750 | 10,000 |
| Medium Boiler | 7.5 | 7,500 | 100,000 |
| Large Boiler | 24 | 24,000 | 320,000 |
You can change the maximum burn rate in the steam controller settings, plus you can use ACBs, Breadboards, and LUA controllers to manage burn rates when configured properly. A common use for ACBs and steam controllers is making steam engines that create Energy when the battery value or percentage is below a certain point. When the value hits the threshold the steam controller will go to maximum burn rate, powering the steam engine and creating additional energy. Once the energy value has increased to the desired level the steam controller will drop back to 0% burn rate.
It is possible for a steam boiler to not produce the max steam pressure of 10 when it's under load, but typically you want your steam engine always producing maximum pressure to give you the maximum engine power and highest efficiency.
Power Generation
- Gearbox - Foundational part of a steam engine. They convert the kinetic energy from the steam pistons into Engine Power. Different size gearboxes have different power limits.
- The amount of kinetic energy or engine power a steam engine creates will be limited by the gearbox; if you need additional power then you'll have to build more than one steam engine. While this creates extra cost and complexity, it does give the benefit of increased redundancy, which is a valuable trait for a Vehicle.
| Part Size | Maximum RPM |
Maximum RPM Kinetic Energy |
Maximum RPM Gearbox Power |
Maximum Engine Power |
|---|---|---|---|---|
| Small Gearbox | 180 | 200 | 600 | 50,000 |
| Medium Gearbox | 150 | 300 | 900 | 100,000 |
| Large Gearbox | 120 | 4,000 | 12,000 | 200,000 |
- Piston - Pistons receive the steam from the boilers and create mechanical power that spins the crankshaft, producing engine power at the gearbox. Each steam engine size has a corresponding piston size. The more steam pressure that is fed into a piston, the more power that piston will create. There is a maximum amount of steam a piston will use at max pressure and a maximum amount of power the piston will produce. Pistons use the amount of steam needed to maintain the needed engine power. This means a piston on an engine with 5% load will use less steam than an engine at 90% load. Additionally, a piston will output a portion of the steam that is fed into it, which allows you to attach outputs from one piston into the input of another piston in a process called compounding. This increases the efficiency of the steam engine at the expense of creating a larger engine, also known as Power per Material (PPM) vs Power per Volume (PPV).
- Large Pistons have serial and parallel versions. They have the same stats, the only difference is the layout of the integrated input and output pipes. Large pistons are the only size with integrated piping.
| Part Size | Maximum Steam Used per Second |
Max Kinetic Energy Created |
Maximum Engine Power Created |
|---|---|---|---|
| Small Piston | 5,000 | 2,000 | 3,000 |
| Medium Piston | 5,000 | 2,000 | 3,000 |
| Large Piston | 40,000 | 16,000 | 24,000 |
- Crank - The centerpiece of a steam engine, which connects the gearbox to the pistons. Small cranks can have up to 4 pistons per crank, while medium and large cranks can have up to 3 pistons per crank. Multiple cranks attached to one gearbox creates a crankshaft, like you see in a real world car engine. It is possible to have a steam engine with only one crank, but it is uncommon and only for incredibly small steam engine designs.
- Small and Medium cranks have a cased variant, which has more health. Large cranks are only cased.
- Flywheel - Built inline with a crankshaft, stores mechanical energy from the steam engine. This can help mitigate issues from short surges of power requirements, and can also be attached to shaft generators to generate energy to power batteries. Flywheels can connect to other flywheels or shaft generators by placing it next to the flywheel (not inline).
| Part Size | Max Kinetic Energy Stored |
Kinetic Energy Loss per Second at Max RPM |
|---|---|---|
| Small Wheel | 400 | 45 |
| Medium (1m) Wheel | 300 | 20 |
| Medium (3m) Wheel | 1,500 | 20 |
| Large Wheel | 12,000 | 150 |
- Shaft Generator - Converts kinetic energy from a flywheel into Electric Energy production. All sizes of shaft generators crate one battery energy per one kinetic energy, and have a maximum conversation limit equal to the max power of the flywheel. Shaft generators are good for when you don't want to build a dedicated engine for energy generation.
- Steam Drill - Can be attached to a crankshaft, using engine power to damage any blocks that hit the drill. The more power being used by the drill, the more damage it will do.
Steam Turbines
Turbines take in steam through a pipe connection and convert it to electricity. Adding more middle segments into a turbine will increase EPM (energy per material) and decrease EPV (energy per volume), making it more efficient at creating energy at the expense of volume and cost. All turbine sizes have the same components.
- Turbine Generator - Foundational part of a steam turbine. All other pieces will branch off of this component.
- Turbine Generator Connector - As the name implies, it connects to the turbine generator.
- Turbine Middle - Middle section used to extend the turbine, allowing for more material efficient designs.
- Turbine Window - Functionally the same as a Turbine Middle, but has a window to see the inside of the turbine.
- Turbine Pipe Connection - The end piece of a turbine. The steam boilers connect to this component.
- Small Compact Turbine - Unique component for small turbines. Single piece that connects to the steam boiler and turbine generator, allowing a smaller sized turbine at the cost of efficiency.
Efficiency is based on the number of turbine blades. Small turbines have two blades per segment, while medium and large turbines have one blade per segment. This means the efficiency of small turbines increases at twice the rate of medium and large tubines. Material Efficiency for a turbine is a Logarithmic Growth, meaning each additional segment of a turbine increases efficiency less than the one before it.
Small Turbine EPM Efficiency.
Medium and Large Turbine EPM Efficiency.
| Number of Turbines |
% Steam Converted (no pressure) |
% Steam Converted (max pressure) |
Max Energy per second |
Max Steam Converted per second |
Max Steam Dissipated per second |
|---|---|---|---|---|---|
| 1 | 32.8 | 53.8 | 268 | 269 | 231 |
| 2 | 54.8 | 68.4 | 341 | 342 | 158 |
| 3 | 69.6 | 78.6 | 393 | 393 | 107 |
| 4 | 79.6 | 85.6 | 428 | 428 | 72 |
| 5 | 86.3 | 90.3 | 451 | 451 | 49 |
| 6 | 90.8 | 93.5 | 467 | 467 | 33 |
| 7 | 93.8 | 95.6 | 478 | 478 | 22 |
| 8 | 95.8 | 97 | 485 | 485 | 15 |
| 9 | 97.2 | 98 | 490 | 490 | 10 |
| 10 | 98.1 | 98.7 | 493 | 493 | 7 |
| 11 | 98.7 | 99.1 | 495 | 495 | 5 |
| 12 | 99.1 | 99.4 | 497 | 497 | 3 |
| 13 | 99.4 | 99.6 | 498 | 498 | 2 |
| 14 | 99.6 | 99.7 | 499 | 499 | 1 |
| 15 | 99.7 | 99.8 | 499 | 499 | 1 |
| Number of Turbines |
% Steam Converted (no pressure) |
% Steam Converted (max pressure) |
Max Energy per second |
Max Steam Converted per second |
Max Steam Dissipated per second |
|---|---|---|---|---|---|
| 2 | 32.8 | 53.8 | 2687 | 2688 | 2312 |
| 3 | 44.9 | 61.6 | 3080 | 3081 | 1919 |
| 4 | 54.8 | 68.4 | 3417 | 3418 | 1582 |
| 5 | 62.9 | 74 | 3698 | 3698 | 1302 |
| 6 | 69.6 | 78.6 | 3930 | 3931 | 1069 |
| 7 | 75.1 | 82.4 | 4121 | 4122 | 878 |
| 8 | 79.6 | 85.6 | 4278 | 4279 | 721 |
| 9 | 83.2 | 88.2 | 4408 | 4408 | 592 |
| 10 | 86.3 | 90.3 | 4514 | 4514 | 486 |
| 11 | 88.7 | 92 | 4601 | 4602 | 398 |
| 12 | 90.8 | 93.5 | 4673 | 4673 | 327 |
| 13 | 92.4 | 94.6 | 4732 | 4732 | 268 |
| 14 | 93.8 | 95.6 | 4780 | 4780 | 220 |
| 15 | 94.9 | 96.4 | 4819 | 4820 | 180 |
| Number of Turbines |
% Steam Converted (no pressure) |
% Steam Converted (max pressure) |
Max Energy per second |
Max Steam Converted per second |
Max Steam Dissipated per second |
|---|---|---|---|---|---|
| 2 | 32.8 | 53.8 | 16122 | 16128 | 13872 |
| 3 | 44.9 | 61.6 | 18482 | 18489 | 11511 |
| 4 | 54.8 | 68.4 | 20502 | 20508 | 9492 |
| 5 | 62.9 | 74 | 22186 | 22191 | 7809 |
| 6 | 69.6 | 78.6 | 23578 | 23583 | 6417 |
| 7 | 75.1 | 82.4 | 24726 | 24730 | 5270 |
| 8 | 79.6 | 85.6 | 25671 | 25674 | 4326 |
| 9 | 83.2 | 88.2 | 26447 | 26450 | 3550 |
| 10 | 86.3 | 90.3 | 27084 | 27087 | 2913 |
| 11 | 88.7 | 92 | 27608 | 27610 | 2390 |
| 12 | 90.8 | 93.5 | 28038 | 28039 | 1961 |
| 13 | 92.4 | 94.6 | 28390 | 28391 | 1609 |
| 14 | 93.8 | 95.6 | 28679 | 28681 | 1319 |
| 15 | 94.9 | 96.4 | 28917 | 28918 | 1082 |
Steam Propulsion
- Steam Jets - Vents out pressure to create thrust. Compared to other means of propulsion this is compact but inefficient, but also works in any atmostphere, like ion engines.
- Steam Propellers - Much larger than standard propellers and rely on a rotating shaft to produce thrust. Connected to a direct steam drive, steam propellers can produce substantially more thrust per material than standard propellers and allows for ships to run on fewer propellers overall.
Types of Steam Engines
Standard Steam Engines
Engines take in steam through pistons and convert it into rotation through a crankshaft. Usage of engine power will slow down the crank, with max efficiency occurring when the engine is at max load.
Efficiency vs. Volume (PPM vs. PPV)
As a baseline, steam engines will perform at their optimal level if they are taking in a maximum pressure of 10 through the boilers and being used under max load.
An engine constantly bleeds energy through friction, so minimizing friction will increase engine efficiency.
A slower engine will experience less friction. Thus, putting an engine into max load will maximize its efficiency. Furthermore, adding wheels will overall decrease an engine's RPM. However, adding wheels has diminishing returns as a shaft gets longer.
Each crankshaft can take in multiple pistons (4 for small, 3 for the others) and generates friction. Resultantly, more pistons per crankshaft increases engine efficiency.
Each piston expels steam at a lower pressure from an output port. This steam can be recycled into another series of pistons, forming a stage. Pistons taking in recycled steam will not contribute as much power as pistons drawing from the boilers but also do not consume extra steam. As a result, adding more stages increases engine efficiency. Most engines will use 2-4 stages.
Direct Steam Drive
A steam engine designed to power a propeller via a crankshaft directly has a slightly different optimal design. The steam engine crankshaft must run through a transmission before going through a propeller. Generally, it is more common for a direct steam drive engine to have only one piston per crankshaft to better fit inside a narrow hull form.
Most importantly, the total thrust produced by a propeller is directly proportional to the crankshaft RPM. As a result, a ship that wants to go fast will want to avoid loading the engine powered by the direct drive to the max and instead may run one engine only to drive propellers and another engine to power internal systems.
The kinetic energy of a steam engine caps out when the steam engine reaches maximum RPM, at which point examining any piston in the steam engine will indicate the level of output used. Much like with engine power, linking up just enough propellers to make full use of the steam engine's kinetic energy right before or as it reaches maximum RPM will maximize the efficiency of the engine.
For large steam direct drive, one piston per stage:
- One piston line can run 2 7m props at 200/240 RPM
- Two piston lines can run 4 7m props at 220/240 RPM
- Three piston lines can run 6 7m props at almost 240 RPM
The number of stages in the piston line is irrelevant for direct drive; it mostly changes PPM rather than power output.
Crank Motors
Crank motors are an alternatve to direct steam drive. They draw power directly from the pool of avaialble engine power, rather than producing it themslves. The motor uses this power to turn a correspondingly sized steam shaft and propeller. This eliminates the need for a tranmission setup and allows a ship's propellers to be physically disconnected from a steam engine, or even use other forms of power. In addition, multiple crank motors can be connected by drive belts to one steam propeller to increase its thrust up to maximum output.
In exchange, crank motors incur an inherent penalty in converting power into kinetic energy; a direct drive setup linked up to propellers will always produce more power per material than a corresponding crank motor setup.
In Practice
Steam engines are a great way to create massive amounts of Engine Power or Energy production. The flexibility of steam engines and the creatino of multiple stages allows players to balance between power density and fuel efficiency.
There are some downsides to fuel engines. They are large, with the large steam engines especially being big enough to require large portions of a vehicle. Additionally, the pipes between steam generation and power generation give steam engines a critical weak point since one missing pipe segment can drain all the steam out of a system. Finally, steam engines require an initial investment of resources to build up steam pressure, which can cause a lag between engine power requirements and production.
Comparison to Other Engines
Steam Engine vs Fuel Engine
- Fuel engines have better power density than steam engines, especially at small sizes. However, steam engines scale upwards better than fuel engines do; at large sizes and full load, steam engines can both offer better PPV and PPM.
- Steam engines do not perform well at close to idle, while fuel engines can be configured to work best at lower RPMs. This makes sizing your engine to match power requirements more important with steam engines than with fuel engines.
- Steam engines only require materials, whereas fuel engines require fuel, which is highly flammable so requires extra protection.
Steam Engine vs Electric Engine
- Steam engines have better power density than electric engines.
- Steam engines are much cheaper than an electric engine and its battery bank.
- Steam engines create a large amount of heat, which can be seen with IR detectors. In comparision, electric engines do not create any heat.
- Electric engines require energy generation, which comes from either extremely expensive RTGs or a generator created from a fuel or steam engine. This makes electric engines typicaly impractical for primary engine power sources.
Idle Efficiency
Even when a standard steam engine is not under load, steam can exit the system through the output valves of the last pistons connected to the crankshaft, resulting in a very low PPM when idle. This considerable inefficiency can be counteracted in a few ways:
- Turning the boilers off naturally stops any material usage. However, steam will continue to exit the system. Any steam lost while the boilers are off must be built up again as the steam engine powers up. This can result in considerable material loss, especially if the boilers themselves become empty.
- Closing valves will prevent the flow of steam. Having a valve between the boiler and the engine and another at the end of the engine will prevent steam from exiting either system, saving materials while the steam engine is not needed.
- When connected to each other and not under load, steam engines of different stages will attempt to equalize pressure. This can bleed off steam from the higher stage to the lower stage, unless a valve is installed. However, the loss of steam between stages is substantially less than the loss from draining boilers on the same-sized engine.
External References
The From the Depths Discord channel is a great way to see user designs and receive help/feedback with your builds.
- Steam Engines by Zuthal - Good breakdown of steam engine components and how to build a proper steam engine.
Below is a list of Youtube videos you can use for learning or for reference.
- Steam Engines Full Guide (2021) by Liv's Lab - Good thorough explanation of steam engines.
- INSTANT Tutorial: Steam Engines & Steam Power by GMODISM - Quick guide explaining the basics of steam engines.