Engine dryers

wrote in message
ups.com...

wrote:

One comment on humidty levels in hangers. In my hanger in the spring
(Michigan) the humidity gets so high that the floor is actually wet.
Also the writing on a white board runs! It seems that the moisture
comes up from the concrete floor.

Regards,
Jerry

I hear you about the moisture. I used to live in a much more humid
climate (Huntsville, Al) and we had a similar issue about humidity,
especially in Winter. When I first bought my plane, I had to wait for a
hangar and thus was left on the tarmac. When a hangar became
available, I began to notice that the plane seemed muggier than before,
when left outside. I began to notice that the radios, etc. began to act
up when I first started a flight. After a while things would clear up
and work fine. It finally dawned on me that inside the hangar in
winter, etc. I never got the warming effect of the Sun (greenhouse I
guess). Moisture was collecting inside the plane at a much higher
level. You could even smell it. I think in many ways staying outside is
better. I often use to pull my plane outside the hangar even when I
wasn't flying just to get that sunshine on the plane to warm it up and
drive the humidity out. On many a cold day, it was nice and warm
inside the plane once you got inside. Those big windows really let the
Sun in and warmed things up even on the coldest of days.

Regards,
Bud

I live North of Atlanta. Occasionally, we have a moist winter day where
you'll open the hangar door and find the entire airframe dripping, as if it
rained inside the hangar. The 100w bulb inside the cowling technique is
probably enough to raise the temperature inside the cowling high enough that
moisture won't condense on or inside the engine in all but the most extreme
circumstances.

KB

wrote:
The 100 watt bulb trick is to merely place a drop cord with a 100 watt
bulb inside the cowl while parked and leave it on 24x7. This was first
suggested as a cheap and easy way to preheat, especially if 2 100 watt
bulbs were used. Simply put plugs or rags or such in the cowl openings,
place a blanket or 2 over the cowl, and while not as good as a good
preheater, did keep the engine at a temp above the desired level.
Aviation Consumer did an article on this in the past. They used the
same trick when they were evaluating the dryers, and found that as with
the preheaters, this trick did not perform as well as the devices
designed for that purpose, but did keep moisture out of the crankcase.
They found that this trick kept the air temp inside the crankcase from
5 to 10 deg above the dew point, so no moisture collected on the engine
internals.

I have to wonder whether the moisture evaporated from the
above-dew-point crankcase distills out on the below-dew-point rocker
arms and valve mechanism.

If you are referring to the issue where some of the preheater systems,
when if left on constantly caused moisture evaporated from the hotter
parts of the engine to condense on the cooler parts (such as you
listed) and cause corrosion, well maybe that occurs. The dryers simply
blow dry air thru the crankcase eliminating (theoretically) moisture
from initiating corrosion. I think that many of the articles we read in
aviation publications take a very simplistic approach to research. I
don't think the charge that if you leave a preheater on 24x7 it will
cause corrosion has ever been proven or disproven adequately, as is
also true with many other things we read. For instance, we are
constantly told that water condenses in the oil in the crankcase and
that we need to fly alot to boil it off. Well, I have done my oil
changes for years (close to 40 oil changes by now) and I usually send a
sample off for analysis. I usually drain the oil overnight, and I don't
usually do it after flying but before, since I like to circulate the
fresh oil through the engine, so the oil is cold from sitting up for a
week or two and should have moisture in it according to common wisdom.
However the analysis reports I get back from Blackstone never show any
sign of moisture in the oil! WTH.
But you might be right. I don't know for sure.

Bud


Dave Butler wrote:
wrote:
The 100 watt bulb trick is to merely place a drop cord with a 100 watt
bulb inside the cowl while parked and leave it on 24x7. This was first
suggested as a cheap and easy way to preheat, especially if 2 100 watt
bulbs were used. Simply put plugs or rags or such in the cowl openings,
place a blanket or 2 over the cowl, and while not as good as a good
preheater, did keep the engine at a temp above the desired level.
Aviation Consumer did an article on this in the past. They used the
same trick when they were evaluating the dryers, and found that as with
the preheaters, this trick did not perform as well as the devices
designed for that purpose, but did keep moisture out of the crankcase.
They found that this trick kept the air temp inside the crankcase from
5 to 10 deg above the dew point, so no moisture collected on the engine
internals.

I have to wonder whether the moisture evaporated from the
above-dew-point crankcase distills out on the below-dew-point rocker
arms and valve mechanism.

"Dave Butler" wrote in message
...
wrote:
The 100 watt bulb trick is to merely place a drop cord with a 100 watt
bulb inside the cowl while parked and leave it on 24x7. This was first
suggested as a cheap and easy way to preheat, especially if 2 100 watt
bulbs were used. Simply put plugs or rags or such in the cowl openings,
place a blanket or 2 over the cowl, and while not as good as a good
preheater, did keep the engine at a temp above the desired level.
Aviation Consumer did an article on this in the past. They used the
same trick when they were evaluating the dryers, and found that as with
the preheaters, this trick did not perform as well as the devices
designed for that purpose, but did keep moisture out of the crankcase.
They found that this trick kept the air temp inside the crankcase from
5 to 10 deg above the dew point, so no moisture collected on the engine
internals.

I have to wonder whether the moisture evaporated from the above-dew-point
crankcase distills out on the below-dew-point rocker arms and valve
mechanism.

The point of the 100w bulb trick is to keep everything under the cowl
(including the crankcase) a few degrees warmer than the outside environment
to raise the under-cowl temp above the dewpoint.

I don't see any way this technique could hurt.

KB

Kyle Boatright wrote:


The point of the 100w bulb trick is to keep everything under the cowl
(including the crankcase) a few degrees warmer than the outside
environment to raise the under-cowl temp above the dewpoint.

I don't see any way this technique could hurt.

KB

The argument is that if the oil in the sump contains significant
moisture, it would be driven out by the heat and then condense on the
upper engine parts, which are cooler. Consider boiling water on your
stove in winter, you can get condensation on the stuff above your
stovetop, even though its warmer than the rest of the kitchen - and it
could be much colder outside the house.

Not sure I buy it, but that's the argumet.

--

wrote:
If you are referring to the issue where some of the preheater systems,
when if left on constantly caused moisture evaporated from the hotter
parts of the engine to condense on the cooler parts (such as you
listed) and cause corrosion, well maybe that occurs. The dryers simply
blow dry air thru the crankcase eliminating (theoretically) moisture
from initiating corrosion. I think that many of the articles we read in
aviation publications take a very simplistic approach to research. I
don't think the charge that if you leave a preheater on 24x7 it will
cause corrosion has ever been proven or disproven adequately, as is
also true with many other things we read.

I agree completely that much of what we read about engine care is based
on folklore and speculation. I used the word "wonder". ;-)

DGB

snip

Dave Butler wrote:

wrote:

The 100 watt bulb trick is to merely place a drop cord with a 100 watt
bulb inside the cowl while parked and leave it on 24x7. This was first
suggested as a cheap and easy way to preheat, especially if 2 100 watt
bulbs were used. Simply put plugs or rags or such in the cowl openings,
place a blanket or 2 over the cowl, and while not as good as a good
preheater, did keep the engine at a temp above the desired level.

snip

I have to wonder whether the moisture evaporated from the
above-dew-point crankcase distills out on the below-dew-point rocker
arms and valve mechanism.

A co-worker had an O-360 jug at his workstation that had pronounced
corrosion on the bottom of the bore, thought to be from excessive use
of a preheater.

Strictly my opinion - I don't buy the need to run engines often to
purge generated moisture. Engines don't produce moisture when they are
standing still, only when they run. The crankcase becomes filled with
blowby CO2 and water vapor during operation. As the crankcase cools,
the water vapor condenses out & combines with any available nitrogen
and sulfur oxides (and maybe lead etc compounds?) to form acids, which
initiate the corrosion. Higher temperatures from always-on preheaters
will accelerate the corrosion, doubling the corrosion rate every 18 deg
F.

What's needed is some way to get the crankcase purged of water vapor
immediately after shutdown. I've now started using a small fan hung on
the the oil dipstick spout to vent the crankcase out the breather pipe.
Unfortunately since I started doing this at 1700 Hrs & 31 years since
it was new, and don't expect to be overhauling the engine soon, I can't
tell you if this will do any good, but the gases that come out smell
really bad.

My unheated hangar in N WI stays dry and warmer since the roof is
fairly dark, so I never have trouble with external condensing moisture.


Clean oil, proper starting, operating, and shutdown procedures, and
storage conditions are important for engine life.

An aircraft stored outside has a completely different set of problems
though.

Robert M. Gary wrote:
Also, from my personal experience the moisture is much more damaging to
the avionics than anything else. If I don't fly on a regular bases in
the winter, my #2 comm display acts strange.

*** I keep two "Eva-Dry" dessicant pods in the airplane. These are
plastic-cased units. They have a color-change window that tells you
when they're full. And an internal heater so you can take them home
and dry them out. I have a spare set that I keep at home. During the
summer they last a month, in the rainy season more like a week.

Since I started using the dessicants, the cockpit is always dry, no
mustiness, no
haze behind instrument faces and no avionics woes.

- Jerry Kaidor

Robert M. Gary wrote:
Also, from my personal experience the moisture is much more damaging to
the avionics than anything else. If I don't fly on a regular bases in
the winter, my #2 comm display acts strange.

*** I keep two "Eva-Dry" dessicant pods in the airplane. These are
plastic-cased units. They have a color-change window that tells you
when they're full. And an internal heater so you can take them home
and dry them out. I have a spare set that I keep at home. During the
summer they last a month, in the rainy season more like a week.

Since I started using the dessicants, the cockpit is always dry, no
mustiness, no
haze behind instrument faces and no avionics woes.

- Jerry Kaidor