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Posted

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There has been much debate about wether or not it is detrimental to leave a engine heater plugged in 24/7.

I left the engine heater plugged in for 2 weeks, during which time I didn't fly. Only had a blanket over the cowl and another over the prop. Engine heater is a rieff with 4- 50w cylinder bands and a 50w sump heater =250w.

I buy a plane so I can dispatch at almost any time and find it a waste to spend extra money on equipment and data service when electricity is only about 20-30 per month for the engine heater.

The oil analysis showed ZERO moisture content. Can we put this OWT to bed now???

Posted

You did consider the condensation of moisture issue...

Leaving the heat on helps evaporate moisture.

Where it goes to another part of the engine and condenses.

Letting the engine sit is bad...

Letting moisture stay in the engine is bad...

Warming the engine with moisture in it could be really bad...

Starting the engine with cold oil is bad...

Using a remote switch is good...

Leaving the oil cap open can vent some moisture...

Leaving the oil cap off while flying is bad...

Using an air dryer (properly) can help...

What can you do?

Go fly while thinking of an answer...

Do this about once each week...

The OWT won't effect you at all...

The lower fuel price goes, the easier this thought process becomes.

Best regards,

-a-

  • Like 2
Posted

I'd say that we need more data. And that silicon number is shit high, while the iron number is a third of my esteemed and expensive factory engine.

Posted

I was reading an Aviation Consumer article today about this OWT. Basically they concluded that a full system (cylinder's and sump) left on continuously would not have a condensation issue. They did NOT recommend leaving on 24/7 with just a sump heater.

Posted

I'd say that we need more data. And that silicon number is shit high, while the iron number is a third of my esteemed and expensive factory engine.

 

Are you still in break in? I would expect a brand new engine to make a lot of iron for a good while.

Posted

I sent off some oil samples in water bottles that still had a little bit of water in them and they came back with zero water in the readings

Posted

Ha I thought I'd get you guys going.

The silicon is high because it's a new motor, that "should" come down. Only had 30 hours on it at time of oil analysis.

Maybe the 2 old comfort blankets overtop of the engine and prop make the difference. When I open the oil door, warm air comes out. The cht and oil are around 100 and the air coming out has to be close to that.

Understand condensation might happen in other areas of the engine, but wouldn't it be very unlikely that none of the moisture made it back to the oil?

Any condensed water that did make it back to the oil would stay. ??

Posted

I sent off some oil samples in water bottles that still had a little bit of water in them and they came back with zero water in the readings

Well there's another variable, there test might not be accurate pertaining to water.... :(

Posted

How about this- leave the heater on 24/7, but then hook a shop vacuum to the filler tube and have it on a timer where it goes off and sucks the air out of the engine say, every other day for 15 minutes? Might that not take care of moisture concerns?

  • Like 1
Posted

For the Lyc, which I owned for half a decade I had an air recirculator which passed the air through a chamber filled with dessicant. Water(moisture) was the problem with inactivity, and also with those short flights which alot of folks seem to have time for more than not. I made a system whcih passed the dried air through the crankcase via the oil filler tube and out the crank case vent. When I used the system I never saw the water droplets on the oil cap and dipstick. Does the engine heater work? Maybe but the tiny aquarium pump is lots less electricity and accomplishes the objective. I have yet to make or buy a similar system for the Ovation however Rocketman made one for his TCM powered rocket and he also has seen the benefits of the dry air system. Engine heater an OWT ? I dont know but I do know what worked for me. These systems can also be purchased if you dont have the time to make your own.

http://home.comcast.net/~r123rs/Documents/Engine_Dryer_Sport_Avi.pdf

Posted

condensation occurs on the cooler side of temperature change. You know from your weather training that as air rises it cools and when the temp reaches the dew point it will condensate into clouds. 

Same principle in your engine. You need two things:

1. Moisture content

2. Temperature change.

 

If the moisture content is low, even moderate changes in temperature will not be enough to pull it out of the air. Heating the air expands it and reduces this content. See many clouds in Arizona? So rising hot air will not form condensation if there is not much moisture it in. Humidity levels below 55% are difficult to extract moisture from.

 

The key to preventing temperature change is covering the cowling with a good insulator. A sleeping bag or better yet a formed fitting cover is necessary. The goal is to eliminate the temperature difference between the inside of the engine and the outside of the engine. No temperature difference, no condensation.

 

So short side of a long story.

Keep the moisture content down by allowing an escape vent (Oil filler cap open)

Eliminate temperature difference between inside and outside of engine (cover the cowling to keep heat around the engine)

 

No more old wife's tales, just science.

  • Like 2
Posted

Engine oil is lighter than water, so when you drained the oil, maybe the oil water mix came out first? If you followed the oil sampling procedure, you would have sampled in the middle of the draining process, thus getting no water. The only way oil and water can be in suspension uniformly throughout will be via an emulsifying agent (not sure if there are emulsifiers in engine oil)

Posted

For the Lyc, which I owned for half a decade I had an air recirculator which passed the air through a chamber filled with dessicant. Water(moisture) was the problem with inactivity, and also with those short flights which alot of folks seem to have time for more than not.

http://home.comcast.net/~r123rs/Documents/Engine_Dryer_Sport_Avi.pdf

Question: how long must a flight be and at what power? I typically fly for an hour plus 10 minutes for taxi, takeoff, landing (55% to 65% power). My oil temps are sometimes 190 and sometimes 160 if it is very cold out. I have my oil cooler covered with 1.5 inch wide strip of hvac tape recommended by my A&P. I'll prolly have to add one more strip now that its getting to be brutally cold.

Posted

attachicon.gifImageUploadedByTapatalk1420417304.527558.jpg

There has been much debate about wether or not it is detrimental to leave a engine heater plugged in 24/7.

I left the engine heater plugged in for 2 weeks, during which time I didn't fly. Only had a blanket over the cowl and another over the prop. Engine heater is a rieff with 4- 50w cylinder bands and a 50w sump heater =250w.

I buy a plane so I can dispatch at almost any time and find it a waste to spend extra money on equipment and data service when electricity is only about 20-30 per month for the engine heater.

The oil analysis showed ZERO moisture content. Can we put this OWT to bed now???

 

 

I have left my Tanis on all winter, for 9 winters straight. There has been no coagulation, "sweating", water in the oil, rust on the dip stick or filler cap, etc. I began doing this with a factory new Lyc. At 800 hrs, we just did a bore scope and everything was perfect. The cam and lobes looked brand new. Oil analysis during this time has been nearly perfect. Personally, Tanis is the better system and I would avoid the Reiff. You really do get what you pay for.

  • Like 1
Posted

Aaron - do you have an engine analyzer? If so, what are the temps for the oil, CHT and EGTs?

For those interested in water solubility in motor oil: http://www.vaisala.com/Vaisala%20Documents/Vaisala%20News%20Articles/VN169/VN169_Factors_Affecting_Water_Solubility_in_Oils.pdf

All right around 100f, but I'm gonna check tomorrow as it will be -15f here in the AM.

  • Like 1
Posted

Question: how long must a flight be and at what power? I typically fly for an hour plus 10 minutes for taxi, takeoff, landing (55% to 65% power). My oil temps are sometimes 190 and sometimes 160 if it is very cold out. I have my oil cooler covered with 1.5 inch wide strip of hvac tape recommended by my A&P. I'll prolly have to add one more strip now that its getting to be brutally cold.

 

Your oil will take 4 degrees per minute to warm up. Minimum t/o for most engines is 100 degrees F, so on a freezing day, you would want to wait a little over 15 mins before you even think of running full power. Then, 30 mins thereafter for for complete lubrication at cruise power.

Posted

Personally, Tanis is the better system and I would avoid the Reiff. You really do get what you pay for.

I, too, assume the Tanis is the better system because it costs more and has been around longer. But "avoid the Reiff"? I've owned 4, on 4 different engines, and they've all worked great and cost significantly less than the Tanis.

Posted

Both warm the engine. Pretty simple. The Tanis has 2 down sides. 1st the heaters occupy the CHT probe spot so round compressed bayonet style sensors are used under the Tanis heat probe. This style sensor is not as accurate as the I the cylinder head probe.

2nd on the 4 cylinder models (not sure on 6 cylinder) only 3 of the 4 cylinders get heaters. Definitely a drawback, where Reiff's are on all 4.

No option for higher wattage. Reiff's comes with 50w cylinder bands or 100w and 50w or 100w sump heater.

The rieff also has a thermostat shut of switch if and when sump gets to a certain temp.

So after remembering the difference and that the reiff costs less. The reiff is defiantly better.

  • Like 1
Posted

I researched this last year (Reiff vs. Tanis) and I feel the Reiff is a better design. The heat source is more spread-out and closer to the center of the engine, so I feel there is a more even heating of the whole mass.

 

Attached is a graph of my system performance. This is with a quilt over the cowl and cowl plugs. I achieved a 110 degree max temp rise. My system is 100W bands on the cylinders, and 100W on the oil pan for a total of 500W. I achieved about 90% of my heat rise in 6 hours. Green line is engine, Blue line is ambient inside the hanger.

 

I don't have a graph, but without the cowl quilt and plugs I achieve a max rise of 45 degrees. Insulating the engine makes a huge difference.

 

The spike in the graph at noon Sunday is the cool-down after a flight.

 

Larry

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