Good stuff Doug.
I've been searching around for a ballpark measure of pump efficiency (delivered volume/theoretical volume) to include in an equation as you presented. Some leakage from the high side to the low side of the pump is inevitable. What little I've found suggests a curve rather than a single value; apparently efficiency goes down with increased pressure and lower viscosity (hot oil). Out of town today so no progress.
<<Looking through the manuals etc and now understnd that most 4 cyl Lycomings have the 0.75" oil pumps, the 6 cyl engines have the 1".>>
Apparently true for the 4-cyls. However, I think I saw some IO-540 models with the same 18109 series impellers. Of course I could be wrong as a soup sandwich <g>
I've been searching around for a ballpark measure of pump efficiency (delivered volume/theoretical volume) to include in an equation as you presented. Some leakage from the high side to the low side of the pump is inevitable. What little I've found suggests a curve rather than a single value; apparently efficiency goes down with increased pressure and lower viscosity (hot oil). Out of town today so no progress.
<<Looking through the manuals etc and now understnd that most 4 cyl Lycomings have the 0.75" oil pumps, the 6 cyl engines have the 1".>>
Apparently true for the 4-cyls. However, I think I saw some IO-540 models with the same 18109 series impellers. Of course I could be wrong as a soup sandwich <g>