Use a Tanis heater for engine dehumidification?

[Jim_R]

I live in Texas, and rarely have to worry about the cold (it's 70 outside today, for instance). However, my plane spent some time up north and had a Tanis heater installed. At the same time, a 120V outlet was installed in the cabin for a space heater to keep the gyros warm, too. Since bringing the plane south, I haven't considered plugging in the heater or using the internal outlet for anything.

But now I'm having humidity problems inside the cabin. To get on top of the problem, I've currently got an extension cord run through the door, with two 75W bulbs in the cabin and Damp-Rid bags hanging fore and aft.

When I was considering how to power the bulbs, I was looking at the outlet inside the cabin, and thought it sure would be nice and easy to just use that. I didn't, though, because it would mean running the engine heater, and I wasn't sure that was such a good thing.

It got me thinking, though...I know there are engine dehumidification systems out there. What about the Tanis heater I've already got? Could it be beneficial to plug that heater in even in warm weather, if I know the plane will sit for a while without flying...maybe on a timer?

Aside from wasted electricity, would there be other drawbacks to doing that?

 

[bbchien]

Use a typical household plug in heater for the cabin, turn it on a hour prior to use and leave the baggage door open to exhaust (or put the heater in there, pointed inwards.

Use the 750 W (LOW power) setting, please. Nothing like warmth and ventilation to get rid of condensation.

 

[Badger]

I know many people use a GoldenRod dehumidifier in their gun safes, maybe it will also work in your situation? ( cabin humidity issue)
http://www.goldenroddehumidifiers.com/aircraft.htm

 

[dmccormack]

Can't get condensation if you don't go below the dew point....

 

[Jim_R]

My current cabin humidity issues are a separate problem, and are the result of the plane leaking during torrential rainstorms for a week while I was away from home and thus not in a hangar.

Back to the original question...would it cause problems if I ran the Tanis heater when it's not cold outside? Would there be any particular benefit to doing so?

 

[Capt. Geoffrey Thorpe]

Can't get condensation if you don't go below the dew point....

It's hard to get above the dew point INSIDE the engine since there is so much water in the blow-by. Unless you have a way to move air in / out of the crankcase, the water that is in there is going to stay in there.

Also, corrosion rates increase with temperature.

 

[dmccormack]

It's hard to get above the dew point INSIDE the engine since there is so much water in the blow-by. Unless you have a way to move air in / out of the crankcase, the water that is in there is going to stay in there.

Also, corrosion rates increase with temperature.

Pulling the dipstick out after shutdown while the engine is still warm should vent the vapor.

 

[Geico266]

Pulling the dipstick out after shutdown while the engine is still warm should vent the vapor.

After every flight.

It is amazing to me that one gallon of fuel burned produces 1+ gallons of water. Blow by is an issue along with not getting oil temps in the 200 F range at least once a flight to boil the water out.

Not a fan of plugging in a Tanis heater for a long period of time. I have seen where it cooked the oil inside of the oil pan. May not have been properly installed or it failed. Reguadless the oil was cooked.

 

[dmccormack]

After every flight.

It is amazing that one gallon of fuel burned produces 1+ gallons of water. Blow by is an issue along with not getting oil temps in the 200 F range at least once a flight to boil the water out.

Not a fan of plugging in a Tanis heater for a long period of time. I have seen where it cooked the oil inside of the oil pan. May not have been properly installed or it failed. Reguadless the oil was cooked.

My little Lycoming is cold running. So I block the oil pan air blast hole with aluminum tape in winter and never fly less than an hour (in winter).

I try to remember to remove the dipstick, but sometimes forget (it's cold in the morning!). But the dipstick never has that scum I've seen on some other dipsticks. I also change the oil between 12-15 hours.

 

[Geico266]

My little Lycoming is cold running. So I block the oil pan air blast hole with aluminum tape in winter and never fly less than an hour (in winter).

I try to remember to remove the dipstick, but sometimes forget (it's cold in the morning!). But the dipstick never has that scum I've seen on some other dipsticks. I also change the oil between 12-15 hours.

Oil temps are important. Too many pilots, IMHO try and keep oil temps in the 180 range ( lower in the winter) , 230F oil temps are not a problem for the oil or the engine. Boiling moisture out of the oil is a good thing.

I have a Vans oil cooler shutter over my oil cooler to allow oil temps to hit 200-220F every flight then I open the shutter and keep it around 200F. It is in flight adjustable.

http://www.vansaircraft.com/cgi-bin...42-108-558&browse=engines&product=oil_shutter

That "white junk" on the dip stick is oil and water mixing. It is corrosive and shows the engine is not getting hot enough.

Tape works great, but let me tell you a story. One Sat I loaded up 3 buddies to go to a breakfast. I had blocked off the oil ccooler with tape and the temps outside were in the 20's. I climbed out to 5,000 agl for the 1/2 hour flight when I noticed oil temps going though the roof! I did everything I could to lower the temps but they kept climbing. I declared an emergency at our destination airport and landed down wind. The FBO, hearing all the commotion on the radio stroles out to the airplane as I parked and said " Put tape on the oil cooler huh?" I said; "How did you know that"? "Third plane today that had high oil temps, the air temps aloft are 70f. The tempurature inversion lesson of the day.

 

[gismo]

I live in Texas, and rarely have to worry about the cold (it's 70 outside today, for instance). However, my plane spent some time up north and had a Tanis heater installed. At the same time, a 120V outlet was installed in the cabin for a space heater to keep the gyros warm, too. Since bringing the plane south, I haven't considered plugging in the heater or using the internal outlet for anything.

But now I'm having humidity problems inside the cabin. To get on top of the problem, I've currently got an extension cord run through the door, with two 75W bulbs in the cabin and Damp-Rid bags hanging fore and aft.

When I was considering how to power the bulbs, I was looking at the outlet inside the cabin, and thought it sure would be nice and easy to just use that. I didn't, though, because it would mean running the engine heater, and I wasn't sure that was such a good thing.

It got me thinking, though...I know there are engine dehumidification systems out there. What about the Tanis heater I've already got? Could it be beneficial to plug that heater in even in warm weather, if I know the plane will sit for a while without flying...maybe on a timer?

Aside from wasted electricity, would there be other drawbacks to doing that?

There are two schools of thought on this and no clear evidence either way. But I suspect that running the engine heater on a timer so it cycles on and off each day would be the worst as far as moisture issues go. I do think it's generally accepted that as long as all parts of the engine are brought to a temp above the dewpoint (which should be the same inside the engine as outside once it's been sitting for a long time) there shouldn't be any condensation going on. That said, corrosion is a chemical reaction and the rate of any chemical reaction increases with temperature so heating up the engine might just cause it to turn to rust more quickly.

In any case I'd be reluctant to waste the electricity. Either plug the cabin dehumidifier in separately or install a switch that shuts the engine heat off when you don't need it.

 

[Jim_R]

Either plug the cabin dehumidifier in separately or install a switch that shuts the engine heat off when you don't need it.

Thanks much for the useful reply. What little info I was able to find via Google matches your answer. I'll stick with the cord-through-the-door trick for now, and maybe consider installing a switch at next annual.

 

[dmccormack]

Tape works great, but let me tell you a story. One Sat I loaded up 3 buddies to go to a breakfast. I had blocked off the oil ccooler with tape and the temps outside were in the 20's. I climbed out to 5,000 agl for the 1/2 hour flight when I noticed oil temps going though the roof! I did everything I could to lower the temps but they kept climbing. I declared an emergency at our destination airport and landed down wind. The FBO, hearing all the commotion on the radio stroles out to the airplane as I parked and said " Put tape on the oil cooler huh?" I said; "How did you know that"? "Third plane today that had high oil temps, the air temps aloft are 70f. The tempurature inversion lesson of the day.

That's some inversion! Fortunately I rarely climb above 2,000'

 

[Capt. Geoffrey Thorpe]

There are two schools of thought on this and no clear evidence either way. But I suspect that running the engine heater on a timer so it cycles on and off each day would be the worst as far as moisture issues go. I do think it's generally accepted that as long as all parts of the engine are brought to a temp above the dewpoint (which should be the same inside the engine as outside once it's been sitting for a long time) there shouldn't be any condensation going on. That said, corrosion is a chemical reaction and the rate of any chemical reaction increases with temperature so heating up the engine might just cause it to turn to rust more quickly.

In any case I'd be reluctant to waste the electricity. Either plug the cabin dehumidifier in separately or install a switch that shuts the engine heat off when you don't need it.

With the dipstick plugged in and the only connection to the outside via a long, skinny, tube, it may take quite a while for the moisture levels to equilibrate (I have no data on how long it may be). If I were to plug something in while the engine is parked, I would use an aquarium pump in either the dipstick or breather. But that won't work for my Rotax which has a sealed crankcase (it relies on blowby to push the oil back to the tank).