[VesselSimulator.git] / KerbalEngineer / VesselSimulator / EngineSim.cs
--- a/KerbalEngineer/VesselSimulator/EngineSim.cs
+++ b/KerbalEngineer/VesselSimulator/EngineSim.cs
@@ -145,7 +145,8 @@
             for (int i = 0; i < propellants.Count; ++i)
             {
                 Propellant propellant = propellants[i];
-                flowMass += propellant.ratio * ResourceContainer.GetResourceDensity(propellant.id);
+                if (!propellant.ignoreForIsp)
+                    flowMass += propellant.ratio * ResourceContainer.GetResourceDensity(propellant.id);
             }
 
             if (log != null) log.buf.AppendFormat("flowMass = {0:g6}\n", flowMass);