Oil Temp in a Climb

[Anticept]

My assumption has always been that, running, they interfere with the free flow of high speed air through the radiators, and that's why they get turned off in flight.

 

Maybe your location behind the radiators makes them less disruptive.

 

Don't really know.

 

They will be turned into generators when they get above rated speed, and try to push power back onto the bus.

[207WF]

It would be worth $2000 to me to solve the high oil temp issue. I looked at the big oil cooler from FD once - the one they use in Europe for towing - but I was told by FD it required a bigger cowling. I have thought about installing an aux cooler, which could be done cheaply, in an area on the firewall near the battery. It would be great to fix this by next summer! WF

[207WF]

Mocfly: I too would like to know more about your fan. Ed, Sandpiper and I all have about the same oil temperature problem and we, at least collectively, have tried everything even Roger can think of! Other designs don't have this problem. I even tried a fan once (actually two tries), but not attached to the back of the oil radiator. Mine was attached at the bottom of the cowl to try to increase air flow out. There was no measureable impact on the oil temps. WF

[WmInce]

Has anyone attempted to experiment with the 'angle' with which the cooler sits?

It seems to me that the more air volume which can pass through the coils would increase the efficiency of heat dissipated.

If the air impacts the cooler face and has to make, even the slightest turn, that would reduce the volume and effectiveness.

Just a thought.

[Roger Lee]

Yes and you need to loosen the fittings on all the cooler attachment points and pull the bottom of the cooler as far forward as it will go. Some seem to move more than others.

[Doug G.]

Loosely related question. Has anyone discovered an easy way to clean bugs from the radiator?

[Anticept]

Loosely related question. Has anyone discovered an easy way to clean bugs from the radiator?

 

Give her a big sloppy tongue-y kiss like you are trying to floss your wife's teeth.

 

 

 

Anyways, once you are done heaving at my statement, just use compressed shop air. You won't get all of the bug guts out, but they will work their own way out over time.

[Roger Lee]

Power washer gets all bugs, dirt and oily grime. Doesn't hurt a thing and you won't believe how much crud can get into our radiators. We has a wash rack at our field. If you don't have that I soak and squirt Oil Eater into the radiator and let it sit a few minutes then throw small containers of fresh water through the radiator from the inside out. It works fair, but nothing like the power washer.

[Anticept]

Power washer gets all bugs, dirt and oily grime. Doesn't hurt a thing and you won't believe how much crud can get into our radiators. We has a wash rack at our field. If you don't have that I soak and squirt Oil Eater into the radiator and let it sit a few minutes then throw small containers of fresh water through the radiator from the inside out. It works fair, but nothing like the power washer.

 

I assume you would be doing this from the back of the radiator, and not the front, right?

[Roger Lee]

Actually because of the placement of the radiator power washing forward and or backward doesn't hurt or get into anything it shouldn't on the engine. I have been surprised by how much stuff come out of some radiators. High oil temps can be caused by several factors. Prop pitch, take off style, coolant hose and oil hose issues, radiator angle, bad connection on a wire, ect... You may have any one of these, but my guess is some have 2-3 things adding up on the temp. Possibly even the temp probe itself and you can check that by swapping out the CHT probe for the oil temp probe. They are the same.

 

Wayne,

Maybe sometime you can come over to Tucson and we can just focus on cooling.

None of us here in one of the hottest states have any major cooling issues. You have to be suspicious of something when we live in such a hot climate and some of you in much cooler climates are having an issue.

[207WF]

We have moved mine around too, getting it square with respect to the hole in the front cowl and as close to the hole as we can. This might have helped a little bit. I am going to take you up on that some time, Roger. WF

[Jerry]

Here in ohio we're getting to 20F for our high temps. The question I have is that my CTSW takes about 15 - 20 minutes to warm up to the required 124F for run up and take off. Once all is warmed up, take off is fine but after flying for about 10 minutes, the oil temp drops and I have the engine warning light on with rpm warning. Is this normal? If not, what could the problem be?

Thanks in advance for your advice.

[FlyingMonkey]

Here in ohio we're getting to 20F for our high temps. The question I have is that my CTSW takes about 15 - 20 minutes to warm up to the required 124F for run up and take off. Once all is warmed up, take off is fine but after flying for about 10 minutes, the oil temp drops and I have the engine warning light on with rpm warning. Is this normal? If not, what could the problem be?

Thanks in advance for your advice.

 

Do you have metal tape over the top of the radiator? If not, you probably need a 2"-3" strip of foil tape on the top of the front of the radiator, across the full span of the radiator. Without tape most of us cannot achieve or maintain appropriate temps in cold weather.

[Doug G.]

My oil thermostat works well.

[Jerry]

^{Thanks for the tip Andy, I'll give it a try tomorrow during my next scheduled flight.}

[FastEddieB]

I have started the plane on 10f-20f mornings now and it starts right up, with a little goose of the throttle (there is no choke).

 

Is that with or without pre-heat?

 

What does ROTAX say about cold weather starts without heat?

 

Does the injected 912 have an accelerator pump? Trying to picture the effect of "goosing the throttle".

 

And, at the risk of sounding repetitious, I would tend to follow the manufacturer's recommendation as to boost pump use. They may just have reasons for specifying its use at certain times.

[Roger Lee]

Hi Eddie,

 

The IS engine after start needs to have the rpm bumped over 2750 (mfg's use 3000 rpm) momentarily to engage the charging system. Until that is done it is running on battery only. Then you get it right back to warm up idle rpm.

[mocfly]

Mocfly: I too would like to know more about your fan. Ed, Sandpiper and I all have about the same oil temperature problem and we, at least collectively, have tried everything even Roger can think of! Other designs don't have this problem. I even tried a fan once (actually two tries), but not attached to the back of the oil radiator. Mine was attached at the bottom of the cowl to try to increase air flow out. There was no measureable impact on the oil temps. WF

Has anyone attempted to experiment with the 'angle' with which the cooler sits?

It seems to me that the more air volume which can pass through the coils would increase the efficiency of heat dissipated.

If the air impacts the cooler face and has to make, even the slightest turn, that would reduce the volume and effectiveness.

Just a thought.

 

 

I installed the fan to test a theory that the amount of air that needed to be pulled thru the radiator/oil cooler sandwich at an increased rate in order to effectively cool the oil during hot weather/aggressive climb configurations. The data gathered gave me the result I was hoping for. The fan has been removed as I test other ways to change increase the pressure differential between the front and rear faces of the cooler assembly.

 

Wm

You're assertion that air flow is right on point. The heat exchange rate in most if not all radiators and oil coolers is calculated based on free air flow at a certain rate thru the fins. The trick cooling design in aircraft is to get as much air thru the cooler without adding additional drag.

I have experienced high oil temps since purchase of my aircraft also and while grounds, sensor error and other issues were initially found to be issues, these have all been eliminated as sources of the high reading. My test data shows air flow thru the cooling sandwich is the issue. I am working on a final solution that is fully documented so my application for an LOA will be accepted both individually and fleet wide for the others experiencing the same temperature issues.

 

 

[WmInce]

. . . " I am working on a final solution that is fully documented so my application for an LOA will be accepted both individually and fleet wide for the others experiencing the same temperature issues." . . .

 

Outstanding!

[mocfly]

Only if it works. Thank you.

[mocfly]

This is very tempting.....loose the oil cooler, simplify the system, reduce the weight and I would guess better overall temp control.

 

[Roger Lee]

A heat exchanger. I had someone take one out of another plane. It's worse than the cooler. It does a poor job and if one is hot then the coolant and oil are both hot. I needs really good air flow with a cool coolant.

[mocfly]

Roger,

How much of an effect does the float level have on the amount an engine either runs excessively rich or lean?

[Ed Cesnalis]

Ho Ed,

 

That tape adjustment won't help and may cause even higher temps.

 

FYI,

Rotax temps are higher in the mid 4000 rpm's and that's the way the system is set up. The 5000's should run cooler than the mid 4000's especially around 4700-4800.

 

I really believe you may have a hose that has a reduced radius bend. Not kinked. My bet is the oil line off the right side of the oil pump and the right side of the oil cooler or the the return line off the bottom of the engine back to the oil tank. These collapse sometimes when the oil heats them up. I would re-route the one on the bottom to come straight out the left side by cy. #2-#4 and then back to the oil tank. This is a big culprit. You may need a 90 degree oil tank fitting because the one on top of the tank is straight. The hose on the pump to the oil cooler may need to have the fire sleeve removed, re-install the hose and fire the engine up and let it get hot to see if that hose collapses.

 

If you have any reduced radius hose it will slow the oil flow and cause it to get hotter.

Are you using standard 50/50 mix anti-freeze?

Make sure you flush out both cooler fins through and through to make sure there is not dirt and oil to reduce air flow over the radiator fins.

 

Over time the rich mixture should help reduce all temps.

 

Roger,

 

I did not do the upgrade to my oil cooler.  Over the winter I thought about it and your theory that the hoses are prone to reduced radius when hot sounds correct.  The capacity of my oil cooler was fine for 1 1/2 years.  It is like new so its capacity should still be fine.

 

Since I'm on my 3rd set of hoses I was reluctant to think they are the problem but your explanation sounds right.

 

When my CT was new I used to do various mountain departures where I climbed steeply instead of going around.  I was amazed at how she climbed and hopefully with your advice above I will get that back.

 

Thanks,  I'll let you know how it goes.

[sandpiper]

First couple of hot days here and my oil temp is already up against the yellow range. IMHO a full throttle 90K climb from S.L. to 3500 MSL with OAT's in the low 80"s should not affect the oil temp. like that. Good thing I don't live in AZ!!