Oil temperature during cold months

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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Nomore767
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Re: Oil temperature during cold months

Postby Nomore767 » Wed Dec 27, 2017 12:30 pm

MrMorden wrote:Using tape is a fine art. I often find I use too little or too much, and then I end up with my temps too high when I climb or too cool in cruise. Yesterday with 32°F OAT was a "too cool" day. Oil temps around 180°F most of the time so I went into a steep WOT climb to 6500ft to get the temps up. That worked well and got me to 220°F. But now I had another problem, I had to get back down! Even on a very shallow descent, the oil temp went down as low as 140°F before I got back down to ~2500ft. At least I got the oil temp up for a bit, but I can't imagine big temp swings like that are ultimately good for the engine.


Agree that it IS a fine art. In the 40's F i'll use a strip of 3" wide metal tape. If the day is closer to freezing as a high I'll add another half width.
I don't press the tape on too hard I just smooth it on and it follows the contours of the surface.

On my RV-12 this provides oil temps on the upper end of the green arc whilst getting the coolant temps into the green for (ahem) the 'heating system". This does provide some warmth on cold days as well as defogging the canopy.

I usually tape a note on the panel during winter to remind me about the metal strip. This is because here in SC the coldest days are less frequent and often followed by a series of days back in the 60'sF in which case the tape would cause the oil temp to go into the upper free/caution range. The other point is that if you're flying early in the day, with frost, use the tape. Later on if ambient temps have warmed, you may need to remove it. If you fly from cold temps to warm, you may need to forgo the tape or use a narrow strip.

Hence the 'fine art' point!

It would be easier to have the shutter with a control from the cockpit. The Remos I flew had a little 'lollipop' thing that would work as a shutter for oil temps. Some of the ELSA guys flying the RV-12 have devised shutters etc but not approved for my SLSA. Besides, the metal tape works fine, lasts a long time. I usually carefully remove it/add it depending on the ambient temp.

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dstclair
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Re: Oil temperature during cold months

Postby dstclair » Wed Dec 27, 2017 12:37 pm

The S4 has a 180F oil thermostat.
dave

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drseti
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Re: Oil temperature during cold months

Postby drseti » Wed Dec 27, 2017 12:54 pm

Nomore767 wrote:here in SC the coldest days are less frequent and often followed by a series of days back in the 60'sF


You're breaking my heart. :evil:
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MrMorden
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Re: Oil temperature during cold months

Postby MrMorden » Wed Dec 27, 2017 2:00 pm

akroguy wrote:For less than arctic conditions, just a drop light with 60 to 100Watt bulb tucked into the cowling with a blanket thrown over works fine.


Do you leave that running overnight? I'm always reluctant to leave electrical items running, lest I return to an airplane burnt to ash (which would be my luck).
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA

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MrMorden
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Re: Oil temperature during cold months

Postby MrMorden » Wed Dec 27, 2017 2:07 pm

Nomore767 wrote:
MrMorden wrote:Using tape is a fine art. I often find I use too little or too much, and then I end up with my temps too high when I climb or too cool in cruise. Yesterday with 32°F OAT was a "too cool" day. Oil temps around 180°F most of the time so I went into a steep WOT climb to 6500ft to get the temps up. That worked well and got me to 220°F. But now I had another problem, I had to get back down! Even on a very shallow descent, the oil temp went down as low as 140°F before I got back down to ~2500ft. At least I got the oil temp up for a bit, but I can't imagine big temp swings like that are ultimately good for the engine.


Agree that it IS a fine art. In the 40's F i'll use a strip of 3" wide metal tape. If the day is closer to freezing as a high I'll add another half width.
I don't press the tape on too hard I just smooth it on and it follows the contours of the surface.

On my RV-12 this provides oil temps on the upper end of the green arc whilst getting the coolant temps into the green for (ahem) the 'heating system". This does provide some warmth on cold days as well as defogging the canopy.

I usually tape a note on the panel during winter to remind me about the metal strip. This is because here in SC the coldest days are less frequent and often followed by a series of days back in the 60'sF in which case the tape would cause the oil temp to go into the upper free/caution range. The other point is that if you're flying early in the day, with frost, use the tape. Later on if ambient temps have warmed, you may need to remove it. If you fly from cold temps to warm, you may need to forgo the tape or use a narrow strip.

Hence the 'fine art' point!

It would be easier to have the shutter with a control from the cockpit. The Remos I flew had a little 'lollipop' thing that would work as a shutter for oil temps. Some of the ELSA guys flying the RV-12 have devised shutters etc but not approved for my SLSA. Besides, the metal tape works fine, lasts a long time. I usually carefully remove it/add it depending on the ambient temp.


In Georgia I have the same issue. Swings between highs of 20-30°F day-to-day are not uncommon. Since I'm ELSA I keep thinking I want to rig a cockpit controlled slider or shutter, but the tape is so easy and I'd always rather fly than spend time tinkering.

The CT has a very wide radiator compared to the RV-12, and the oil cooler is behind it. It seems like the oil cooler is always breathing "preheated" air in that config, but it works. I usually need about half the radiator width in take when it gets into the 40s, full width in the 30s. I try to go with less tape that more, since I've had times where I had to land and some yank tape off to keep things cool if I overdo it.
Andy Walker
Athens, GA
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2007 Flight Design CTSW E-LSA

Warmi
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Re: Oil temperature during cold months

Postby Warmi » Wed Dec 27, 2017 3:57 pm

Yes, indeed, my S4 does have 180F thermostat already installed - confirmed that today with my mechanic.

Well, today it was -4 F ,pretty darn cold, even for Chicago ... so it was an ultimate test. I put one strip ( 2 inches ) and went flying - oil was keeping up around 170-175 in the cruise and went down to 160 during power-on descents.

The thermostat just can't keep up with such extreme cold - will have to tape it a bit more ... or stop flying in such an ugly weather :-)
Flying Sting S4 ( N184WA ) out of Illinois

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David
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Re: Oil temperature during cold months

Postby David » Wed Dec 27, 2017 6:47 pm

I installed the shutter from Van's and modified it for the RV12 when I lived in PA and now live in Maine and fly well below zero most of the winter. I can keep my temps up.

Slight mod to make it larger to fit over the oil cooler.

Image
Image

Fully adjustable in the cabin in flight with outside temps -10 to -20 and oil temps managed up to 220 deg

I bought an Alien Heater for keep it 50 deg all the time and turn it up to 70 deg once I get to the hanger. Turn on the heater in the hanger and 15 min later after the preflight good to to :D

Image
https://aerothermheaters.com/
David
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Re: Oil temperature during cold months

Postby Warmi » Wed Dec 27, 2017 6:57 pm

My hangar is heated so the engine never goes below 50 degrees, and I also rigged a simple heater , similar to what Drseti proposed but the in-flight temperatures is what worries me. Since my plane is a LSA I can’t install random stuff so will just tape the he’ll out of it :D
Flying Sting S4 ( N184WA ) out of Illinois

Nomore767
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Re: Oil temperature during cold months

Postby Nomore767 » Wed Dec 27, 2017 10:43 pm

drseti wrote:
Nomore767 wrote:here in SC the coldest days are less frequent and often followed by a series of days back in the 60'sF


You're breaking my heart. :evil:

Hence the move from PA!

Nomore767
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Re: Oil temperature during cold months

Postby Nomore767 » Thu Dec 28, 2017 2:59 am

David wrote:I installed the shutter from Van's and modified it for the RV12 when I lived in PA and now live in Maine and fly well below zero most of the winter. I can keep my temps up.

Slight mod to make it larger to fit over the oil cooler.

Image
Image

Fully adjustable in the cabin in flight with outside temps -10 to -20 and oil temps managed up to 220 deg

I bought an Alien Heater for keep it 50 deg all the time and turn it up to 70 deg once I get to the hanger. Turn on the heater in the hanger and 15 min later after the preflight good to to :D

Image
https://aerothermheaters.com/


I'll have to find out from Vans whether its approved for installation on my SLSA. Although...never as cold in SC as it gets in Maine.

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FastEddieB
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Re: Oil temperature during cold months

Postby FastEddieB » Thu Dec 28, 2017 7:56 am

I think I’ve posted before that the manufacturer of the Sky Arrow was nice enough to include a flight-adjustable baffle arrangement:

Image

(Mine was not delivered with the “Removable Radiator Shutters”. Maybe I should ask about those.)

Anyway, my baffle is just a flat plate that rotates up and blocks the flow of air from behind the oil cooler and radiator.

That said, on really cold days temps can stay very low, even with the baffle closed. But at least it does speed warmup to some extent.
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roger lee
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Re: Oil temperature during cold months

Postby roger lee » Thu Dec 28, 2017 9:28 am

The occasional low oil temp isn't an issue like when you descend even if it is for a whole flight. What you don't want is this to be a habit. The oil needs to get to at least 200F+ to help cook off contaminates. So anywhere from 200F - 225F is fine. My one issue with shutters is even when open they have areas that are blocked off that reduce air flow and while not an issue in the winter it is enough in warmer climates to cause high oil temps in many aircraft, but not all..
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Jim Hardin
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Re: Oil temperature during cold months

Postby Jim Hardin » Thu Dec 28, 2017 9:58 am

drseti wrote:Directly at the engine block. But with the blanket thrown over the cowling, the whole engine bay ends up reasonably warm. You can use a non contact IR thermometer to see hot spots and cold spots.


Thanks for the update.

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Re: Oil temperature during cold months

Postby akroguy » Sun Dec 31, 2017 12:29 am

MrMorden wrote:
akroguy wrote:For less than arctic conditions, just a drop light with 60 to 100Watt bulb tucked into the cowling with a blanket thrown over works fine.


Do you leave that running overnight? I'm always reluctant to leave electrical items running, lest I return to an airplane burnt to ash (which would be my luck).


Oh yeah, have done it many times over the years with a couple different planes. It never gets really hot with just a blanket thrown over the cowling, just takes the edge off the chill. Probably helps the battery the most. I have a small electric heater with a length of dryer duct that is much hotter, but pulls a lot more current.

Since I live with the airplane right outside my kitchen door (airpark home), I should eventually hear a smoke detector by the time only half the airplane becomes an ash pile. :P :lol:

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dstclair
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Re: Oil temperature during cold months

Postby dstclair » Fri Jan 12, 2018 5:14 pm

Here in Dallas it really doesn't get cold but lately it's been cold enough that a preheater of some sort would be a good idea. I was thinking of doing going the light route with something like: Https://www.amazon.com/Bayco-Trouble-Light-25-Foot-SL-425/dp/B000256R14/ref=pd_sbs_60_2?_encoding=UTF8&pd_rd_i=B000256R14&pd_rd_r=94KXAJ5CKX1B0EG6733F&pd_rd_w=72B3L&pd_rd_wg=HjE3D&psc=1&refRID=94KXAJ5CKX1B0EG6733F
and use a thermostatic plug that automatic kicks on at below 35F then turns off at 45F: http://www.thermocube.com/

Anyone use a thermostatic plug before?
dave


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