High oil temp question.

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Roxi5m9
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High oil temp question.

Post by Roxi5m9 »

A fellow pilot recently took his DA40 up and forgot to raise the flaps up on the climb (no seriously, its not me just saying it’s someone else to save harrassment, lol). He climbed from sea level up to 6000 feet before he noticed the oil temp was in the yellow arc at 220 degrees, and after reducing power and assessing, realized the flaps were in TO position. Upon lowering the nose and retracting the flaps the oil temp immediately came down quickly. Has anyone else experienced this? When you climb with a flatter deck angle does that restrict airflow into the nacelle to the point air doesn’t get down into the scat tubing that diverts air to the oil cooler? Surprisingly he said the CHTs were normal. I’ve never seen high oil temps ever, even with high CHTs. Had 6 qts of oil.
N597RA 40.444
‘04 DA40-180
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5M9, Marion, KY
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Rich
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Re: High oil temp question.

Post by Rich »

You don't say anything about climb speed or fuel flow. With TO flaps the DA40 will tend to climb at a lower airspeed, though rate of climb still stays pretty high. I've found that a low-speed extended climb will produce higher oil temperatures. CHTs can be held in check with fuel flow, but not so with oil temps. The air supplied to the oil cooler is fed through a channel built into the right side of the cowling - no scat tubing involved. The intake of this channel is nestled out of the direct main flow of the right cowling opening.

Basically I figure this behavior is normal.

This view is from the prop hub pointing to the right side of the back of the cowling opening, revealing this oil cooler intake (the dark area indicated by the arrow):
Oil Cooler Intake.jpg
If you look straight on at this cowling opening the oil air intake is almost entirely hidden from view.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Roxi5m9
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Re: High oil temp question.

Post by Roxi5m9 »

Rich wrote: Wed Nov 10, 2021 7:45 pm You don't say anything about climb speed or fuel flow. With TO flaps the DA40 will tend to climb at a lower airspeed, though rate of climb still stays pretty high. I've found that a low-speed extended climb will produce higher oil temperatures. CHTs can be held in check with fuel flow, but not so with oil temps. The air supplied to the oil cooler is fed through a channel built into the right side of the cowling - no scat tubing involved. The intake of this channel is nestled out of the direct main flow of the right cowling opening.

Basically I figure this behavior is normal.

This view is from the prop hub pointing to the right side of the back of the cowling opening, revealing this oil cooler intake (the dark area indicated by the arrow):

Oil Cooler Intake.jpg

If you look straight on at this cowling opening the oil air intake is almost entirely hidden from view and fuel flow was normal as well (15 ish GPH)
Thanks Rich. He said the airspeed was about 10 knots lower than normal (cruise climb at 100 knots and 500 FPM). Basically, things seemed mostly fine, not noticed with passenger and ATC distractions, until the oil temp went amber. My bad on the oil cooler air routing. Recalled incorrectly from memory. Thanks for sharing your experience.
N597RA 40.444
‘04 DA40-180
ATP, CFI
5M9, Marion, KY
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