Winterizing airplane

[MMontoya]

I fly an open cockpit AcroSport II in Colorado. I am at the end of my flying season, and am interested in thoughts on winterizing the airplane. Over the years, I have spoken to several mechanics, and airplane owners on what they do to store an airplane for about 5 months.

Some folks have recommended everything from draining fluids, to just putting the battery on a trickle charger, to running the airplane every couple of weeks or so. Colorado is a dry climate, which, I am sure, makes a difference in how one stores an airplane. As for running the airplane periodically, I have tried to fly when it is 40 F before, and I have only made it about I trip around the pattern before I had to land and thaw out, and the engine didn't get up to temperature. I am thinking that running the airplane on the ground periodically in the winter does more harm than good.

Thanks,

Mike

[FlyingRon]

Your option is to properly store the engine (which involves changing and putting fresh (dry) oil NOT draining it, fogging the cylinders and putting in desicant plugs) OR get out every few months and fly it.
Just starting it up and running it up on the ground is going to do more harm than good is correct.

[rosiejerryrosie]

I'm interested in why your both think running it on the ground will do more harm than good. If the engine is run until it is up to operating temperature, how does the engine know if it is three feet or three thousand feet above ground?

[DanChief]

Jerry -- these air-cooled engines are meant to have air flowing over them. When we sit and run them on the ground, the heat is concentrated on certain spots, causing uneven heating. Also, we don't run them at full power on the ground, so they never reach true operating temperature.

I try to be airborne within 10 minutes of startup. It's not always feasible (KTEB, for example), but is best for the engine.

For winter flight in the Chief I cover certain cowl openings with aluminum tape. The engine temps stay in the green and I actually get some cabin heat!

[Joe LaMantia]

I'm no expert, but from what I've read and been told the biggest problem with long term storage is rust. Ron's suggestions are in-line with several articles that recommend desicant plugs, short time run-ups only end up adding water to the engine oil and increasing the probability of rusting. I think you might do well to do a "search" of this subject for previous articles in "Sport Aviation", this problem has been with us for a long time.

Joe

[rosiejerryrosie]

Jerry -- these air-cooled engines are meant to have air flowing over them. When we sit and run them on the ground, the heat is concentrated on certain spots, causing uneven heating. Also, we don't run them at full power on the ground, so they never reach true operating temperature.

I try to be airborne within 10 minutes of startup. It's not always feasible (KTEB, for example), but is best for the engine.

For winter flight in the Chief I cover certain cowl openings with aluminum tape. The engine temps stay in the green and I actually get some cabin heat!

I'm confused, Dan. " these air-cooled engines are meant to have air flowing over them" but "For winter flight in the Chief I cover certain cowl openings with aluminum tape." Dosn't the tape stop some of the air?

I have, in the past, run the Continental on the ground, facing into the wind, until I reach operating temperature. In the winter, it usually takes some time to reach that point. It would seem that facing into the wind and the 'prop wash' provides a significant amount of cooling - to the extent that it takes much more than 10 minutes to reach operating temperature. Do we have a valid point here or is this a long standing 'aviation old wives tale'....

[rosiejerryrosie]

Joe, I agree that rust (moisture) is the real culpret, and desicant plugs and cylindar fogging are the best approach, but if I run my engine until it reaches operating temp, I have been led to believe that 'burns off' accumulated water (moisture) that would lead to rusting. How would increasing the temperature lead to more water? If it is thought that the cooling after a good runup to operating temp causes water to condense, how come it doesn't happen in the summer when we are running the engine more frequently? Or is it thought that the more frequent run ups burn off the moisture before it has a chance to induce rusting? If that it the case, more frequent runups in the winter should accomplish the same thing - but, with the cost of fuel these days, desicant plugs and fogging would be considerably less expensive.

[Dave Stadt]

Joe, I agree that rust (moisture) is the real culpret, and desicant plugs and cylindar fogging are the best approach, but if I run my engine until it reaches operating temp, I have been led to believe that 'burns off' accumulated water (moisture) that would lead to rusting. How would increasing the temperature lead to more water? If it is thought that the cooling after a good runup to operating temp causes water to condense, how come it doesn't happen in the summer when we are running the engine more frequently? Or is it thought that the more frequent run ups burn off the moisture before it has a chance to induce rusting? If that it the case, more frequent runups in the winter should accomplish the same thing - but, with the cost of fuel these days, desicant plugs and fogging would be considerably less expensive.

It takes a considerable amount of time once the engine is up to temp to get rid of all the moisture. Just getting up to temp will not do the job and just because the oil is up to temp doesn't mean the entire engine is at operating temp. Good rule is if you start the engine fly for at least an hour.

My Operation Manual says to avoid long ground runs. I figure they know what they are talking about. The rear cylinders certainly are not getting much cooling air if you are doing extended time, high power ground runs. I would think the rear CHTs would get quite high.

[Bill Greenwood]

Mike, as Ron says , fresh oil change, and you might run some Marvel Mystery Oil in the gas on one last
flight after the oil change, ,maybe spray some Marvel or engine or best yet preservative oil on the clyinders. May not need desicant plugs, can''t hurt.
DONT RUN UP ENGINE UNTIL YOU ARE READY TO FLY. Oil companies say it takes 15 min or so of inflight temps to get any water out of the oil.
I stored a acro biplane, Rose Parakeet , open cockpit , one winter in Crested Butte, did nothing to preserve it and had not problems in the spring, at least as far as I know.
I am in Aspen and Boulder, where are you?

[Joe LaMantia]

Good Topic!
Here's a bit more on my take regarding water. When you run your car or airplane engine it gets warmer then the outside air and yes it will get rid of water and fuel that has diluted the oil in the crankcase. When you shut it down, the moisture in the air, will condense and a bit will wind up back in the crankcase along with a bit raw fuel. There are at least 2 issues here, first the humidity available and second the amount of time the new dilution gets to sit before you run the engine again and burn it off. The humidity is generally lower in winter than sumer and certainly a lot less out west then the rest of the country so that issue may not be a big deal for a plane sitting in Colorado or Arizona. I just got back from a 3 week trip out there and saw humidity levels as low as 22%. Those of us from the Mid-West consider a "dry" day around 60%. My personal flying season runs from March to the first snow fall which is usually around Xmas. I think that is pretty typical of a Mid-West private pilot, so we're talking about a 3-month period of sitting. If I owned my own aircraft and didn't have a heated hanger I would do the oil change thing and maybe fogged the cylinders with WD-40, then use the plugs. I wouldn't bother with starting the engine and warming it up unless I was actually going to fly it on a regular basis. This is pretty much in-line with Bill's comment, I would use the desicant plugs maybe even go so far as to build a simple dry air pump. I saw an article in Sport AV on that subject not all that long ago, they even had a home-built little kit that was pretty good at keeping condensation low and engine rust away!

Joe