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]

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.

[MMontoya]

Joe,

I had remembered a recent article this past year on the subject of oil that mentioned airplane storage. I will search again. Thanks.

[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'....

[DanChief]

Jerry -- some of the cowling openings are taped over in winter (usually the hole in front of the oil pan). There's still plenty of air coming in through the main eyeballs on either side of the prop at my insanely high speed flight of 70-80 MPH.



As you probably know, the O-145 is a cool running engine. In temps below 35 it rarely gets the oil warm enough to ensure all moisture is boiled off. (I also have limited baffling (anyone have drawings for the LA-65??))

Prop wash does not cool the engine much -- most of the air is moving outside the circumference of the engine. The Service manual for the O-145 recommends ground ops not exceed 2 minutes in warm temps (!)

Here's an extract from the Lycoming O-145 Operations Manual:

GROUND RUNNING AND WARM-UP-- the LYCOMING 0-145-B2 engine is an air pressure cooled engine that depends on the forward speed of the airplane to maintain proper cooling. Therefore, particular care is necessary when operating this engine on the ground. To prevent overheating, it is recommended that the following precautions be followed:
Head airplane into the wind
Avoid prolonged idling at low RPM as this practice may result in fouled spark plugs
Limit ground running to 4 minutes in cold weather and to 2 minutes at temperatures above 70 F.

Here's some info taken from the Lycoming Flyer:
B. ENGINE GROUND OPERATION
The engine ground operation greatly influences formation of lead salt deposits on spark plugs and exhaust valve stems. Proper operation of the engine on the ground (warm-up, landing, taxi and engine shut-down) can greatly reduce the deposition rate and deposit formation which cause spark plug fouling and exhaust valve sticking.
1. Proper adjustment of the idle speed (600 to 650 RPM) fuel mixture, and maintenance of the induction air system will ensure smooth engine operation and eliminate excessively rich fuel/air mixtures at idle speeds. This will minimize the separation of the nonvolatile components of the high-leaded aviation fuels greatly retarding the deposition rate.
2. The engine should be operated at engine speeds between 1000 and 1200 RPM after starting and during the initial warm-up period. Avoid prolonged closed-throttle idle engine speed operation (when possible). At engine speeds from 1000 to 1200 RPM, the spark plug core temperatures are hot enough to activate the lead scavenging agents contained in the fuel which retards the formation of the lead salt deposits on the spark plugs and exhaust valve stems. Avoid rapid engine speed changes after start-up, and use only the power settings required to taxi.
3. Rapid engine cooldown from low-power altitude changes, low-power landing approach and/or engine shut-down too soon after landing or ground runs should be avoided.
4. Prior to the engine shut-down, the engine speed should be maintained between 1000 and 1200 RPM until the operating temperatures have stabilized. At this time, the engine speed should be increased to approximately 1800 RPM for 15 to 20 seconds, then reduced to 1000 to 1200 RPM and shut down immediately using the mixture control.

Also:

Extended ground operation can cause excessive cylinder and oil temperatures.



More:

Preventing a buildup of contaminants is just as important as eliminating those that do form. Avoiding long periods of ground operation is a vital step since moisture can enter the breather, but will not vaporize when the oil is not heated to normal operating temperatures. Ground running also involves a slightly rich mixture which contributes to the formation of lead sludge in the oil. During flight, the deposit of lead sludge in the oil can be minimized by proper leaning.

[MMontoya]

Ron,

Thanks for the reply. In the past I have done an oil change, put the battery on a digital trickle charger, and left it at that. While I haven't experienced problems in the spring, I don't know what unseen harm I have done. The one thing I know, is that I turn into a popsicle long in about 5 minutes airborne, so flying in the winter is not an option. I will look into the desicant plugs. I haven't used them before. One last thing; does the fuel system need special consideration for storage of 4 or 5 months?

Thanks,

Mike