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I hate it when this happens...

Piper J3

Well Known Member
I went out to the airplane yesterday to begin condition inspection. Weather was warm with rain in northern Ohio. I opened the hanger door and it looked like a rain forest. Airplane was soaking wet from condensation. I hate it when this happens and it seems to be more often with climate warming…

I can only imagine what is going on behind the scenes…. Inside of wings, fuselage, and stabilizes are most likely drenched with water. Engine I’m sure is soaked, but crankcase is closed to ventilation, so probably OK. What really bothers me the most is the instruments. Dual Dynon EFIS, transponder, comm radio, ADS-B transceiver, two iPads, intercom, ELT…. All soaking wet inside from condensation.

Then overnight, the temp dropped to freezing. I’m trying to put this episode out of my mind and will wait until spring to bring airplane back to life…
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Pretty normal for us southern states ... just about any early morning in the spring it's like this ... but I've never noticed condensation inside the cockpit or on the instruments :confused:

Typically it's just collecting on the outside surfaces, do you keep your cockpit closed or open?
 
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Maybe a heat blanket or other source of heat inside the cabin could minimize this? Especially for instrumentation. Or better yet an outside the cabin heat source with duct routed to the inside. That's a lot of condensation.
 
Keeping the air around the engine and in the cockpit above the dew point would seem to be a wise thing if such a thing happens a lot. I have the same thing happen in my boat's engine compartment and cockpit in the spring when we get those kind of temperature swings. The most prominent result in my case would be mold. Engine corrosion would be a secondary concern, although that seems like a more pressing problem in an airplane. I do keep my airplane hooked up to a circulating dehydrator 24/7/365 when in the hangar.

I solved that problem with my boats years ago by using a couple of cockpit fans during the winter and spring. There are a variety of models, and they're pretty cheap. They only run about 75-100 watts...it doesn't take much power to just keep the temps above the dew point. You could accomplish the same thing with a 100 watt light bulb on a drop cord, although I think the attached circulating fan makes those dedicated heaters a better device.

https://www.amazon.com/Caframo-Limi...-lpcontext&ref_=fplfs&smid=ATVPDKIKX0DER&th=1
 
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Canopy is closed when airplane is in hanger. I’m thinking about adding a small (150W 12V) space heater inside the cabin to be controlled with a humidity switch. Space heater and humidity switch would be located in closed cabin – both low voltage DC for safety.

Anybody doing this?
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Common down here. The airplane gets cold when winter air comes from the NW, then we get warm wet air off the Gulf. The fix is an ordinary box fan left running in the hangar. With air circulation, the surface temperature of the airplane remains close to the air temperature at any given moment....no condensation.
 
The weather in western PA has inspired a paint idea. Rat rod maybe?
 

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Remember, heating the air also increases its capacity to hold moisture, so when it gets a little colder...

A dehumidifier (larger one, which either needs to have a drain tube run outside, or needs to be emptied regularly) has helped in many cases. I have a similar hangar that would do the same thing at times.

And like Dan said, the box fan thing is for sure useful. That's what I do in my (current) hangar. Searching Amazon for something like "24 in. High Velocity Shop Fan" will bring up many options if you want to *really* move some air and have it be a (fairly) portable unit.
 
Any of you ever install a roof barn vent. I have a none heated equipment building that was doing the same thing. This building use to have an oil furnace thus the ss chimney to installed a barn vent( one that the wind turns). I leave a small opening on the opposite end of the building from the roof vent and I find a big difference with condensation. I think that as the outside temperatures change the roof vent brings the inside temperature quicker to the same as the outside temperature. Temperature equalizes and reduces condensation.
Worked for me.
 
The problem in the northern states is bit more difficult than in the south. The floor of an unheated hanger freezes up hard and the airplane sitting over that frozen concrete will lose radiant heat to the cold floor. Airframe temp can remain below air temp, and dew point, day after day after day. Circulating air through the room just results in more condensation. I've think that throwing a bit of heat into the airframe and engine compartment is the only solution, short of heating the entire hangar. I also throw some thin styrofoam sheets and rugs under the airplane to create a thermal break between the airframe and floor. Not sure if it helps much, but it can't hurt.
 
Great idea about the box fan. That's similar to what citrus farmers do with fans mixing the varying ambient air to protect their trees from frost. If you own your hangar you might investigate spraying the ceiling and walls with spray-in foam. We did 2" on the walls and bifold door and then 2.5" on the ceiling. You can feel the difference just walking in from the outside. Add an air circulation box fan like Dan mentioned and things ought to stay nice. With the insulation a small space heater or electric oil-filled radiator could be added. Another benefit with spray-in foam in a metal building is getting all the cracks sealed to keep wind-blown dust out in the Spring.
 
Maybe a heat blanket or other source of heat inside the cabin could minimize this? Especially for instrumentation. Or better yet an outside the cabin heat source with duct routed to the inside. That's a lot of condensation.

I use a pet bed heater.

A heated blanket (for human beds) would be nicer and cover more area but they all have switches that cannot be turned on by my SwitcheOn box. I've considered cutting the cord on a heated blanket and installing a plug so that I could use one of these but I wasn't certain if the switch contained some sort of regulator.

Example:
https://www.petco.com/shop/en/petcostore/product/kandh-pet-bed-heater
 
Keeping the air temp and the building temp close to the same temp. is the key to moisture build-up. I have concrete floor, no insulation and no problem with moisture. I have abundant air vents in the hanger ceiling. Just keep the air temp the same as the outside.
 
when i get this moisture and i happen to be at the hangar i set up a box fan and feed it from a timer that is set to go off in 12 hrs. at least that gets rid of it when i run into it. in the spring the floor sweats a lot as the frost is going out. again, the box fan helps warm the floor up to oat and evaporate the water.
 
I’m still looking at options to heat cabin interior to prevent condensation. I found a 12V 100W heater with a small fan that might do the job.

My PC680 battery is connected to an Odyssey OBC-6A battery charger 24/7 whenever the airplane is in the hanger. I can easily run this heater off the airplane battery and the charger will top off as necessary. A small 12V temperature controller can be set for 70F shutoff. The heater would be fused for safety…
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Keeping the air temp and the building temp close to the same temp. is the key to moisture build-up. I have concrete floor, no insulation and no problem with moisture. I have abundant air vents in the hanger ceiling. Just keep the air temp the same as the outside.

If I heat my hangar at all, I get ice on the roof melting, which runs off to the ground in front of my hangar, then freezes. Best case….a 6 foot strip of ice and ice ridge just outside the bifold making it difficult or impossible to get the plane out. Worst case…the door freezes to the ground and won’t open. I know this from experience with a couple of bullet heaters a couple of years ago while doing a winter avionics project.

If one doesn’t have an insulated and heated hangar, best/simplest solution in this climate is to manage condensation by decreasing humidity in the engine. Fortunately (or unfortunately) up here the dew point and ambient temps in the winter are generally far enough apart that condensation on the airplane and in the cockpit doesn’t happen.
 
I’m still working this problem and have decided to just monitor the situation before taking any action... I just ordered two recording temp/humidity sensors and will place one in the airplane cabin and leave one out in the hanger. By comparing the two stored temp/humidity readings I should be able to tell if the cabin is getting condensation. It’s a starting point…
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Metal building insulation is relatively cheap when installed during construction. They make products simply called “metal building insulation”, a roll of fiberglass faced with a vapor barrier. It’s rolled out before the sheet steal is screwed down. Unfortunately, many hangars are built just like the one shown on the opening page that is for rent. Nothing.
Insulation and venting avoids the condensation problem. Adding insulation to an existing metal building is doable but not easy or economical.

On the Coast, I heat with forced air to 60deg. F and have a commercial dehumidifier. Electricity is cheap here but it is still an expensive bill in the winter. I keep the hangar at 50% or better humidity. Nothing corrodes and I don’t need to preheat! Not an option for everyone especially those in cheaply built rental hangars.
 
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Air Dryr 1000

I too get condensation in the hangar sometimes (OR coast). I have one of these that I keep on the floor of my cockpit in the winter. No fan just some low heat. I honestly don't know if it does any good but I feel like it can't hurt. It does mean the seats aren't so hard when I first get in :)
 

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Jim,
You need to move to Phoenix. This part of the globe has already been warmed…no condensation issues.
Rich
 
Rich
Are there snakes there? I hate snakes.

Can you imagine a snake slithering up front from the baggage compartment? Bad enough I have to watch out for yellow jacket (read anaphylactic shock) in the cabin. I carry epipen, but don't know how that would work for snake bite. I'm giving myself the creeps.....
 
Years ago I had a hangar in rural AZ at Buckeye Airport (KBXK). One day while doing a preflight I noticed what looked like a dirty pile of rags off to the side. I got about 3 feet from it before I realized it was a rattler. Fortunately it was winter (what you easterners would call a brisk fall ). They are prettier lethargic at 50F. I left him alone and he left me alone!

My buddy is a retired USAF pilot who was an A-10 instructor at Davis Montha in Tucson. He told me preflight could be interesting because the rattlers liked to crawl into the shade under the wing and snooze by the tires in summer.

Yep, we got snakes!
 
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