Oil Cooler Delta Pressure

[pa38112]

I purchased an already flying RV6A with a known oil temp. problem on hot days. The builder tried to avoid the usual high oil temp. problem by installing the cooler behind a NASA duct on the cowling instead of in the typical location at the back of the plenum.


Engine: 0-360
Prop: F.P.
Cowling: Sam James
Oil Cooler: Postech 7 row (P20003C)
Oil Temps: 190F at 70F ambient; 230F at 100F ambient
Delta P accross the cooler: 0.8 Inches H2O

I though the problem could be that there is not enough pressure drop (air flow) accross the cooler. My plan was to duct the cooler exhaust to a low pressure area at the bottom of the cowling. Today I installed some termpoary tubing at verious locations inside the cowling to find the best delta pressure from the cooler intake side to the exhaust side. What I found on my test flight is that the exhaust is already at the lowest pressure area inside the cowling.

Im wondering:
a.) If anyone is successfully cooling an 0-360 with the same oil cooler I have?
b.) Does anyone know what the pressure drop is accross their oil cooler? I don't know if 0.8" is hight, low, or about right.

[DanH]

Originally Posted by pa38112

Does anyone know what the pressure drop is across their oil cooler? I don't know if 0.8" is high, low, or about right.

Very low. Typical delta pressures would be (ballpark) 3" H2O at 100 knots, and 12" or so at 200 knots.

[pa38112]

Thank you, Dan. I found a PosiTech performance chart that starts a 2"and goes to 18"... However; everything I read on the forum is that even people with a standard oil cooler configuration have oil temps. similar to mine.
I am very tempted to purchase a 12 row cooler and mount it in the exact same spot. - I'll have to give this a lot more though.