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I still working to improve my oil cooling -
Renesis engine, PSRU 2.8:1, Catto 76X88 composite prop, water and oil
radiators under engine at about 30 degrees to inlet air flow, James
cowl - shark intake under spinner .
See pictures below.
Today I flew and recorded some temperature and static pressure numbers
for anyone to comment on.
Test conditions:
90 deg OAT = inlet air temperature
About 6500 foot altitude
TAS - GPS and EM-2 : 165 mph
Manifold pressure 20in.
RPM 5700
Water Temp - 192 deg F
Oil temp leaving oil cooler - 207 deg. F
Oil temp in oil pan - 235 deg. F
Temp of heated air leaving oil cooler -135 deg F (135-90 = 45 deg temp
rise of cooling air through the oil cooler)
Temp of heated air in cowl low and near firewall 133 deg. F
I measured static air pressures at 5 points inside the cowl as follows:
1). Inlet side of oil cooler: 10.5 in water
2). Back side of oil cooler: 4 in water ( 10.5 - 4 = 6.5 in water
pressure drop across oil cooler.)
3). Midway between oil cooler and firewall: 2.75 in water
4). Right side within 4 inches of firewall and 3 inches above bottom of
firewall: 2 in water
5). Left side within 4 inches of firewall and 3 inches above bottom of
firewall: 2 in water
Before these tests Bobby H. and I were thinking I needed more outlet
area to improve my cooling. I am seriously considering
a big cowl flap to lower the pressure in the cowl. Does this data
support this position?
Hopefully better minds than mine will know!!
Dennis H.
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