on my last flight I noticed my oil temp was only 158F as I have not blocked my oil cooler. I attached the dehydrator an pulled the engine humidity down.
going on my second year this dehydrator material looks OK. I have a closed loop system and just let it run 24/7.
Steve, All the black beads are why I switched to a 5 min purge in advance of providing dry air though the bead bed. The purge gets the super water rich and oil vapors out of the crankcase fast. The purge uses a mattress inflator.
yeah, a 30 minute purge without the return line connected is now my plan. extend the life of the beads!
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Again, this is all empirical. No data to support dehydrators as being efficacious in establishing TBO, but I proceed because it's cheap, easy, and the doctrine of "can't hurt/might help".
This is data I collected with and without a closed loop dehydrator. The temperature and humidity sensors were inside the crankcase.
Good paper. Good read. Here in Humid AF Florida, lots of extra precautions are needed to protect your investment. The day/night temperature swings here help airframes and PPs to “breath” in moisture every day/night cycle. If ignored, it can make things ugly, quick.
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My assertion is that ambient humidity has no bearing on the crankcase humidity -in or out. Combustion chambers with open valves are another story, but not what we are addressing with the typical dehydrators.
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As I said, there’s no good data to demonstrate that using a dehydrator will make a difference in getting an engine to TBO. It seems reasonable to draw that conclusion, but inductive reasoning is all we have to support it. OTOH, I have about $30 in my dehydrator and after a flight I can hook it up in 60 seconds. The time and money that it costs me is negligible in the scheme of aircraft ownership, so…why not?I sure would like to see some test results to support this. While the engine mass could be a factor, we also have barometric issues and standing water in the engine. Mass transport process also may weight in.
My assertion is that ambient humidity has no bearing on the crankcase humidity -in or out. Combustion chambers with open valves are another story, but not what we are addressing with the typical dehydrators.
Lots of OWT so I ran a test. I took at juice bottle dryed it then added some water. The cap modified with 5/8" ID hose to represent the breather tube. I prepared for change. If there was breathing then there would be loss of mass. Short version. After 3 months in my garage the test was terminated as no change in mass could be measured. Lots of temperature change in there from normal changes and sudden due to opening and closing of the door. Everything a hangar would have but the stabilizing thermal effect of a crankcase.
Maybe I did not make the statement clear. My bad, I quibble that Florida humidity is worse for crankcase humidity than Phoenix. I assert is it bad in both cases and no beneficial difference, thus a crankcase dehydrator is beneficial to both.@ BillL
I respect your posts. You're one of the good guys who actually backs-up his statements with related theories and application versus anecdote; hence my respect.
My assertion is that ambient humidity has no bearing on the crankcase humidity -in or out
I'm surprised by this but maybe I'm not completely following all of your logic. Relative volumes, Delta T spreads (winter months with sunny days), alphas of the relevant materials especially relative to air, etc.
In my early experience, our early go-to test for this phenomena was actually a Ph test (coastal air) and followed by measuring air quality with data logging when needed. For mission critical systems, we wound up reclassifying enclosures, adding trickle purges, adding space heaters/keeping motor field windings juiced, etc.
Following your logic, an engine dehydrator would be of zero benefit. Unlike your other posts, I'm not in agreement.
Respectfully,
msf
I
Lots of OWT so I ran a test. I took at juice bottle dryed it then added some water. The cap modified with 5/8" ID hose to represent the breather tube. I prepared for change. If there was breathing then there would be loss of mass. Short version. After 3 months in my garage the test was terminated as no change in mass could be measured. Lots of temperature change in there from normal changes and sudden due to opening and closing of the door. Everything a hangar would have but the stabilizing thermal effect of a crankcase.
I was surprised as well.Surprised by that result. I would have expected some water loss. A more relevant test would be to measure the humidity level inside the bottle. Not sure we can assume that the lack of water mass elimination directly correlates to a constant high humidity of the air mass in that bottle. I would expect that that air inside the bottle matches the ambient humidity level.
Larry