Sizing
Pressure-fed rocket engine sizing is a closure problem.
A useful first design pass is not just a thrust number. It is a consistent set of chamber pressure, propellant flow, throat area, nozzle expansion, injector pressure drop, feed pressure, warnings, and review assumptions.
Updated June 12, 2026.
The variables move together.
In a pressure-fed engine, chamber pressure and thrust are tied to mass flow and throat area. Injector pressure drop sets part of the upstream pressure requirement. Nozzle expansion changes vacuum performance and can introduce over-expansion context at sea-level or low-altitude conditions.
RPL Engine Workbench keeps these quantities in one solved case so geometry, reports, and export artifacts do not drift away from the assumptions that created them.
What the workbench is good for.
- Comparing pressure-fed design points early in a program.
- Keeping nozzle, injector, feed-budget, and report assumptions visible.
- Producing CAD and review artifacts from the same solved case.
- Surfacing warnings before a result is used outside the app.
Engineering boundary
Preliminary sizing software helps teams iterate faster, but it does not replace qualified engineering review, test data, organizational safety processes, structural analysis, or final hardware qualification.