Wernher: Rocket Works

Wernher adds a procedural liquid rocket engine designer to KSP. Choose a cycle, select individual propellants and configure the hardware. The mod calculates thrust, specific impulse, dry mass, cost and engineering constraints from your design.

This is an AI-created hobby project, built from my ideas and instructions. It started as a personal experiment for fun, with no ambition to become a major, serious mod project. This mod is for anyone else who enjoys tinkering with liquid rocket engines. Expect bugs and approximations; this is not a professional engineering tool.

Eight engine cycles

• Pressure-fed: tank pressure pushes the propellants into the chamber.
• Gas generator: a separate gas generator drives a turbine and dumps its exhaust. Merlin uses this type of cycle.
• Electric pump: an electric motor and battery drive the pumps.
• Closed expander: fuel absorbs heat in the cooling jacket, drives the turbine and enters the chamber.
• Expander bleed: some heated fuel passes through the turbine and is discharged overboard.
• Fuel-rich staged combustion: fuel-rich preburner gas drives the turbine, then burns in the main chamber.
• Oxygen-rich staged combustion: the same general arrangement with an oxygen-rich preburner.
• Full-flow staged combustion: separate fuel-rich and oxygen-rich branches drive their turbines. Raptor uses this type of cycle.

These are configurable cycle models, not exact replicas of the real engines mentioned above. Eight working examples provide starting points for your own designs.

Individual propellants and configurable tanks

Choose components separately: liquid oxygen, kerosene, liquid methane, liquid hydrogen, ethanol, methanol, nitrogen tetroxide, MMH, UDMH and water as a diluent. Multi-component mixtures are supported within the model's chemistry limits. Adjust mass fractions with sliders, or use Reference mixture ratio to restore the recommended oxidizer-to-fuel ratio while retaining the proportions of a fuel blend.

Stock LiquidFuel/Oxidizer tanks gain configurable compartments with independent resources, volumes and fill levels. Match a tank to an engine automatically or configure it yourself. Stock LiquidFuel and Oxidizer remain available. Feed pressure affects tank mass; tank construction and pressure can only be changed in the editor.

Design the hardware

• Chamber and injector: chamber pressure, throat size, chamber geometry and characteristic length, one to four chambers, and injector pressure drop.
• Nozzle: expansion ratio, relative length and exit flow angle.
• Feed system: inlet pressure, line losses, pumps, turbines and preburner settings. Electric pump designs include motor efficiency and battery energy/power density.
• Cooling and structure: regenerative or film cooling, cooling channels, coolant fraction, materials, wall thicknesses and safety margins.
• Controls: minimum throttle, a variable-area injector, startup and shutdown response, design burn duration, ignition count, gimbal range and actuator response.
• Covers: straight, tapered or rounded permanent covers, plus a separate jettisonable interstage shroud. The upper diameter can follow the attached part.

Mass and price are built up from the engine's equipment. Higher pressure, additional propellants and deeper throttling come with hardware requirements. The designer checks cooling, strength, power balance, feed pressure and operating limits, with short messages suggesting what to adjust.

Analysis and in-game behavior

• Separate vacuum and sea-level thrust and Isp figures.
• Cycle flow diagrams, hardware estimates and plots, with a virtual test duration from 5 to 60 seconds.
• Saved engine designs, built-in examples and application to symmetry counterparts.
• A procedural 3D model that changes with the design, moving gimbals and surface attachment.
• Animated plumes influenced by propellants, atmospheric pressure and nozzle parameters, plus turbine exhaust where the cycle calls for it.
• Running and ignition audio. An ignition is spent when throttle rises from zero, not simply when the engine is activated at zero throttle.
• Automatic mass balancing from the homeworld's radius and gravity, transitioning smoothly from stock KSP scale to Earth scale. KSP and RSS profile configs are included: engine mass uses a ×4 multiplier at Kerbin scale and ×1 at Earth scale.
• Russian and English interfaces, following the game's language setting.

Quick start

1. Find Wernher — configurable liquid engine in the engine category, attach it and select Open Wernher designer in its part menu.
2. Open Designs → Examples and choose a working starting point. W-01 / Pioneer is a useful first engine.
3. Select the cycle and propellants in Components. After changing propellants, use Reference mixture ratio, then adjust the other hardware tabs.
4. Review Diagram and Analysis, resolve any errors and click Apply. Saving a design to the library does not apply it to the part.
5. Open Configure compartments on a stock tank, use the engine-matching button, select your engine and apply the tank configuration. Engine mixture fractions are by mass; tank compartments are by volume. Automatic matching accounts for component density.
6. Check fill levels, feed pressure and staging. Restarts need remaining ignitions; electric pump engines also require ElectricCharge.

Recheck the tanks after changing the engine's mixture or inlet pressure. Existing tanks are not automatically reconfigured.

Installation and compatibility

Built for KSP 1.12.5. Copy the archive's GameData contents into the game's GameData folder. ModuleManager is required and included; keep a single suitable version if you already have it.

The engineering model uses simplified physical relationships and empirical estimates. It does not calculate full chemical equilibrium, combustion instability or cryogenic boiloff. Plume colors are approximate visual representations, not spectral simulations.

Automatic scale detection is not full Realism Overhaul integration. The stock tank patch skips parts already controlled by RealFuels, B9PartSwitch, InterstellarFuelSwitch or FSfuelSwitch. Compatibility with every mod collection has not been tested.

Back up saves and craft before installing beta-1. For bug reports, include KSP.log, your game version, mod list and an engine design or craft file that reproduces the problem.

License

MIT. Copyright (c) 2026 Vordzi.

This license applies to Wernher. The bundled ModuleManager retains its own terms, included in GameData/ModuleManager.NOTICE.txt.