On Pressures in the Liquid Propellant Rocket Engine Part II: An Experimental Review

Panu Bieneck

2026.079.0012

DOI https://doi.org/10.59332/jbis-079-01-0012

In this final part of the series of articles, the equations derived in Part I are compared with experimental results from Ref. [2], whose data is re-used and re-analysed in light of the theoretical framework presented in Ref. [4]. Using proportionality and regression analyses, key performance quantities are examined as functions of chamber and feed pressure. A consistent pattern emerges: optimal engine performance occurs when the pressure ratio pf/ pc reaches a minimum, coinciding with maxima in specific volume and characteristic velocity. This observation supports the theoretical prediction that pf/ pc > 1 is a necessary condition for LPRE operation. The historical ARS data, though rarely cited, offers sufficient resolution to validate the model with high probability. The findings suggest that pf/ pc may serve as a fundamental design parameter for LPREs and warrant renewed research using modern instrumentation.

Keywords: Liquid Propellant Rocket Engine, Chamber Pressure, Feed Pressure, Novel Calculation Method, Specific Volume