RPL Engine Workbench logo RPL Engine Workbenchby Rocket Propulsion Lab

RPL Engine Workbench · native app for Windows 11 and Apple silicon macOS

From target thrust to a consistent engine case, nozzle DXF, and review-ready report.

Engine Workbench sizes the chamber, feed system, injector, and nozzle from one solved case. It exports DXF contours for CAD, PDF/CSV/JSON reports, and preliminary axisymmetric flowfield results, and it reduces hot-fire test data back against the design model. It runs locally on Windows 11 or an Apple silicon Mac.

Download Windows 11 Beta Download for Apple silicon Mac

Mac 1.0.0 · signed and notarized. Windows 1.0.0 Public Beta · unsigned installer. Built-in trial, no license key required. Personal $29/month or $199/year; Business $799/year — see pricing.

Current scope

Engine Workbench is for preliminary design of pressure-fed liquid engines. It sizes the engine, feed system, injector, and nozzle; runs preliminary axisymmetric flowfield cases; and exports the resulting geometry and reports.

Current releases
Mac 1.0.0 · signed and notarized. Windows 1.0.0 Public Beta · unsigned. Windows 10, Windows on Arm, and Intel Macs are not supported.
Engine type
Pressure-fed liquid, steady-state operating point
Solves
Coupled sizing from target thrust, mass flow, throat diameter, injector geometry, or tank pressure; injector and feed-system sizing; bell, conical, and TIC nozzle contours; preliminary axisymmetric nonreacting flowfield cases; hot-fire test-data reduction
Exports
DXF, PDF, CSV, JSON, VTK, PNG, MP4 (where applicable)
Not included
Solid or hybrid motors, reacting combustion CFD, turbopump cycle analysis, conjugate heat transfer
Boundary
Preliminary design output. Not a substitute for qualified engineering review, testing, safety review, or export-control review.
Download View pricing

What a case looks like

A project is one engine case. The solved operating point feeds every downstream output, so the geometry, the report, and the flowfield views always share the same assumptions.

  1. Define the operating point. Propellants, chamber pressure, mixture ratio, expansion ratio, ambient condition, and a sizing target: thrust, mass flow, throat diameter, injector geometry, or tank pressure.
  2. Solve the engine. First-pass or coupled steady-state, with thermochemistry from embedded CEA-referenced tables or an optional local RocketCEA install. Convergence state and data provenance are reported, never assumed.
  3. Size feed and injector components. Unlike doublets, triplets, and showerheads: orifice diameters, injector pressure drop, momentum ratio, and O/F consistency checks.
  4. Generate nozzle geometry. Bell, conical, and TIC contours with throat, exit, length, and separation-screening context.
  5. Inspect flowfield results. Preliminary axisymmetric, nonreacting nozzle and plume cases with residual status and transient playback.
  6. Compare test data. Reduce measured hot-fire records to effective c*, Cf, discharge coefficients, O/F, and Isp, and calibrate the design model against them.
  7. Export the case. PDF report, DXF contour, CSV/JSON data, VTK fields, and images or video of the solved fields.
Product details Methods and assumptions
Solve summary showing a converged coupled solve with status and warnings
Solve summary: convergence status, warnings, and stale-result flags for the active case.

Flowfield Studio

Preliminary axisymmetric, nonreacting flowfield analysis of the solved nozzle and plume: steady-state and transient cases, density and Mach-number fields, residual status, and PNG/VTK/MP4 export. It runs on the same case that produced the geometry and the report.

It is a preliminary inspection tool, not reacting combustion CFD. Convergence state and solver provenance are shown with every result.

Flowfield Studio details Flowfield tutorial
Nonreacting temperature-field playback of an inviscid sea-level external plume, plumefire colormap. Preliminary result.

Checked against a documented engine

The published reference case is the Apollo Lunar Module Ascent Engine: pressure-fed, fixed-thrust, hypergolic, vacuum. NASA and contractor records supply the inputs; the application's outputs are compared against the same records.

QuantityHistoricalRPLDifference
Vacuum Isp309.7 s307.97 s−0.56%
Total flow5.08 kg/s5.155 kg/s+1.47%
Effective c*1,724.7 m/s1,616.6 m/s−6.27%

The c* comparison is a diagnostic, not a match claim: Boeing's figure is a production-injector acceptance-test reduction. The package explains the difference instead of hiding it. This is reference-case agreement, not whole-solver validation.

Reference package and sources Reproduce it in 15 minutes
High-contrast rendering of the application-exported Apollo LMAE reference nozzle contour
The LMAE reference nozzle contour from the downloadable evidence package.
Engine sizing summary report generated by RPL Engine Workbench
The report records solved outputs, assumptions, warnings, and export context for the case.

Reports and CAD handoff

The PDF report states what was solved, which assumptions and thermochemistry source were used, and which warnings apply. The DXF contour comes from the same solved case, so the geometry used for CAD handoff matches the reported case.

Sample outputs DXF export tutorial

Licensing

Personal is available monthly or annually for noncommercial use; Business permits commercial use. Every paid option includes the core design, export, and Flowfield workflows. Plan limits are shown below, and a purchased key activates the app you already installed.

Personal Monthly

Noncommercial · monthly flexibility

$29per month

One named user doing personal, educational, academic, hobby, or other noncommercial work.

  • Engine, injector, feed-system, and nozzle workflows
  • Flowfield Studio up to 250,000 mesh cells per solve
  • DXF, VTK, PDF, CSV, and JSON exports; project saving
Buy Monthly Personal

$29/month, automatically renewed monthly at $29 unless canceled before renewal. One-device activation limit. Taxes and currency are calculated at checkout. 7-day defect-based money-back guarantee.

Personal Annual

Noncommercial · best annual value

$199per year

One named user doing personal, educational, academic, hobby, or other noncommercial work, including an individual member of a university team.

  • The complete application — every released workflow
  • Full Flowfield Studio with no plan-tier mesh cap
  • DXF, VTK, PDF, CSV, and JSON exports; project saving
Buy Annual Personal

$199/year, automatically renewed annually at $199 while the subscription remains active and unchanged unless canceled before renewal. Taxes and currency are calculated at checkout. 7-day defect-based money-back guarantee.

Business

Commercial use · complete product

$799per year

One named commercial user. For company work, consulting, paid engineering, and internal commercial R&D.

  • The complete paid application — every released workflow
  • Commercial-use rights for work delivered to a company, customer, or employer
  • DXF, VTK, PDF, CSV, and JSON exports; project saving
Buy Business License

$799/year, automatically renewed annually at $799 while the subscription remains active and unchanged unless canceled before renewal. Taxes and currency are calculated at checkout. 7-day defect-based money-back guarantee.

Licenses may not be shared. Teams needing several users should request volume pricing. Cancel and manage subscriptions in the Freemius Customer Portal. See Vendor Terms and the Freemius EULA.

Learn the application

Step-by-step tutorials cover the tasks engineers repeat most: creating an engine case, sizing a nozzle and exporting DXF, sizing an injector, running Flowfield Studio, reading residuals, and exporting reports and media. The documentation hub and glossary cover the rest.

Download All tutorials