REFLECTOR: Oil Pressure Effects From Cooler Arrangement

[Brian Michalk]

In the spirit of sharing, I have some data related to the effects of a 
single oil cooler vs. two coolers in parallel.  Unfortunately, my logged 
oil temperatures are being held hostage by a bad serial port on the 
Autronic, which logs oil temperature data.

I have an oil pressure sensor mounted before the oil filter, and an oil 
pressure sensor on the engine galley, so this measures the pressure drop 
across the filter and oil cooler.

Last weekend, I had a parallel cooler arrangement.
This weekend, I capped off one cooler.

 From searching internet sources, I should have seen a reduction in 
engine oil galley pressure with the single cooler due to its higher 
resistance to oil flow compared to the parallel arrangement.

What I observed is a maximum of 18PSI pressure differential between the 
two sensors.  During climbout, filter pressure reached 102PSI, and my 
minimum galley pressure happened on roll out, and was 35PSI. The maximum 
differential occurred during a low power cruise, about 2400 RPM, and was 
very constant up to the point I hit redline on the temps and came in for 
landing.

I will be reconfiguring with split cooling lines, and testing for series 
pressure differences, and will let you guys know what I find.  At this 
time, my plan is to:
1) fly with split lines, single cooler
2) fly with split lines, parallel coolers
3) fly with split lines, series coolers