Winter Operation

[N201MKTurbo]

While you are doing all this preheating, don't forget the battery.

[N201MKTurbo]

4 hours ago, Marauder said:

 

If you are planning on flying to an airport, check to see if they have a heated hangar for you to keep the plane in for a period before your departure.

For those of us who live or lived in really cold areas, the issue about whether it will start or not is really not the primary concern. It is the lack of lubrication in those few minutes after you start a cold soak engine that creates the wear. Do it enough times and the issue you will see is not some catastrophic failure, rather you’ll wonder why you are doing an engine rebuild at 1,700 and not the 2,000 you expected to get out of the engine.

Another overlooked area is the gyros. I carry a small ceramic heater that I run for an hour before startup. Again, it won’t manifest itself as an immediate gyro failure, just adds wear that can shorten the life of the gyro.

For those of us living in cold climates, installing heaters and carrying the extra stuff with us makes sense. For those that occasionally visit cold areas, you can seek out a heated hangar while you are visiting.

I pre-heat anytime it gets below 40° (F).




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That's what a lot of people think, but is there any real data to support it? Every day that it is freezing cold out at the airport millions of people start their cars without preheating and it doesn't seem hurt them. I would think that a few weeks of disuse would cause a worse lubrication situation then starting a cold engine. Now a disused engine in the cold may be a bad situation, but back in the day the plane rarely went more than three days without being flown.

[N201MKTurbo]

Here is some good science to read:

http://www.sciencedirect.com/science/article/pii/S0196890414001939

It doesn't say much (didn't read it all) about accelerated wear, but it does support my contention that cold high viscosity oil makes it real hard to start.

Enjoy!

[Marauder]

4 minutes ago, N201MKTurbo said:

That's what a lot of people think, but is there any real data to support it? Every day that it is freezing cold out at the airport millions of people start their cars without preheating and it doesn't seem hurt them. I would think that a few weeks of disuse would cause a worse lubrication situation then starting a cold engine. Now a disused engine in the cold may be a bad situation, but back in the day the plane rarely went more than three days without being flown.

There has been a ton written on the pre-heating subject. For those of us who have lived in really cold climates it's more than just a way to make it start easier. Yves and Ned can probably tell you stories. My favorite was parking my plane in Jamestown, NY to eat at the restaurant. It was hovering around freezing and a cold front pushed through while we were eating. I came out to find my tires frozen to the tarmac in ice puddles.

https://www.avweb.com/news/maint/182846-1.html

https://generalaviationnews.com/2014/12/18/tips-for-cold-weather-engine-starting/

https://www.lycoming.com/content/operating-cold-weather

https://www.lycoming.com/sites/default/files/Cold Weather Starting.pdf

[N201MKTurbo]

12 minutes ago, Marauder said:

There has been a ton written on the pre-heating subject. For those of us who have lived in really cold climates it's more than just a way to make it start easier. Yves and Ned can probably tell you stories. My favorite was parking my plane in Jamestown, NY to eat at the restaurant. It was hovering around freezing and a cold front pushed through while we were eating. I came out to find my tires frozen to the tarmac in ice puddles.

I have a few thousand hours flying in below freezing weather. FWIW.

The best one was landing in Vernal Utah at sunset and taxiing in through slush. It all froze solid as a rock. Wheels wouldn't turn. I couldn't even tow it into a hangar. The airline I was working for offered the deicing truck to thaw it out. We tried for two hours and couldn't get the truck to start. It wasn't until the next morning that I found someone with a kerosene heater to melt the ice off of the landing gear.

[N201MKTurbo]

20 minutes ago, Marauder said:

There has been a ton written on the pre-heating subject. For those of us who have lived in really cold climates it's more than just a way to make it start easier. Yves and Ned can probably tell you stories. My favorite was parking my plane in Jamestown, NY to eat at the restaurant. It was hovering around freezing and a cold front pushed through while we were eating. I came out to find my tires frozen to the tarmac in ice puddles.

https://www.avweb.com/news/maint/182846-1.html

https://generalaviationnews.com/2014/12/18/tips-for-cold-weather-engine-starting/

https://www.lycoming.com/content/operating-cold-weather

https://www.lycoming.com/sites/default/files/Cold Weather Starting.pdf

FWIW,

This is all hear say and suggestions with no data. The only data offered is a reference to a study done by Tannis who has a vested interest in preheating.

[ArtVandelay]

Our engines require oil to be splashed around, I assume there is a point where the oil will no longer splash. For those with refrigerators in their hangar, maybe you can do a science experiment, put some oil in the freezer section and see if it’s viscous enough to be splashed.

[steingar]

Our engines have both aluminum and steel. They shrink in the cold at dissimilar rates. Starting aircraft engines in the cold can be disastrous. Your car engine doesn’t have this mixture and wasn’t designed in the Eisenhower administration.

My little heater guy has a long cord, and I xarry both it and an extension chord during the winter. Never been anywhere I couldn’t plug it in.

[gsxrpilot]

We've got a place in Durango and fly the Mooney up there summer and winter. It usually lives out on the ramp, but we're usually not there for more than a long weekend. If we get snowed on, we'll haul it into a hangar to clean the snow off and warm it up a bit but both of my Mooneys have always handled the cold really well.

The worst part of this is that the cover was soaking wet and very heavy when we finally departed. 

[carusoam]

Below 20°F, 100LL loathes evaporating...

Oil doesn't like to flow...

And you only get a few chances to start before the battery is dead.

Have a plan for these, and you are good.

Best regards,

-a-

[Hector]

The coldest I have flown my C ever was -30 C. Not again...Since then my limit is -20C. I do not block the oil cooler with anything.

I pre-heat with a propane forced air heater.

Yves

 

If it ever got that cold here in Florida we would not know what to do and we would just die. Winter in Florida is the best time to fly!!

 

 

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[yvesg]

1 minute ago, Hector said:

 

If it ever got that cold here in Florida we would not know what to do and we would just die. Winter in Florida is the best time to fly!!

 

 

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Right Hector. We are planning to go south or south west again this year but this time on the week before Christmas. Are you working  during that week?

Yves

[Hector]

Yvesg, I should be off that week. Definitely let me know if you are coming this way.


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[Hank]

1 minute ago, carusoam said:

Below 20°F, 100LL loathes evaporating...

Oil doesn't like to flow...

And you only get a few chances to start before the battery is dead.

Have a plan for these, and you are good.

Best regards,

-a-

You just reminded me of my cold weather start procedure. Sure, the oil pan, oil, cylinders, pistons, etc. are warm, but ice cold fuel will cool it off rapidly. 

Make the following two changes to my normal cranking procedure:

• Pump the accelerator 4-5 times instead of once or twice.
• Delay while waiting for the cold fue, to evaporate by:

1. Wind and set the clock in the yoke.
2. Position red hands to overlap white clock hands.
3. Put on and adjust headset.

Then crank away! Without the engine running, there's no heat . . . .

[drapo]

19 hours ago, Ned Gravel said:

I am with Yves on this issue.  My pre-heat is a bit different but it gives similar results.  I have a Reiff plug in set of heaters on the engine and the oil sump that take no more than one hour to get temps up to close to 60 deg.  

The biggest headache in winter flying is making sure the tie down spot is sufficiently clear to allow the airplane to get pulled out or pushed back.  That can take at least an hour.

I'm based not to far from Yves and Ned and I also use the Reiff system along with a small ceramic heater for the interior. I plug it in as I arrive, and by the time I've cleared the snow around the airplane, I'm pretty much ready to go!

[Oscar Avalle]

My hangar is unheated, so I use an electrical oil pan heater. I switch it on 18 hrs before I fly. 

Oscar

[steingar]

9 hours ago, carusoam said:

Below 20°F, 100LL loathes evaporating...

Oil doesn't like to flow...

And you only get a few chances to start before the battery is dead.

Have a plan for these, and you are good.

Best regards,

-a-

Were it not for subfreezing days I'd not fly in the winter.  Only time we get clear skies here.  Not fun spooling up, but the aircraft flies just fine.  Better than that, the airplane loves it.  Fast climbs, and I can fly low, get good views and not brill or get tossed around by thermals.  I love winter flying.  Then again, I love flying any time.

[N201MKTurbo]

Another helpful winter hint.

If parked outside, always park with one propeller blade down. If not snow can blow into your spinner, melt and refreeze into a solid block of ice. If you start the engine it will almost shake the engine off its mounts.

With one blade down the melt water will drain out.

[ShuRugal]

12 hours ago, steingar said:

Our engines have both aluminum and steel. They shrink in the cold at dissimilar rates. Starting aircraft engines in the cold can be disastrous. Your car engine doesn’t have this mixture and wasn’t designed in the Eisenhower administration.

My little heater guy has a long cord, and I xarry both it and an extension chord during the winter. Never been anywhere I couldn’t plug it in.

My Honda motorcycles from the 70's and 80's all have aluminum blocks with steel liners.  My father has a few from the 50's and 60's.  None of our bikes have ever exploded due to dissimilar thermal expansion rates in the winter.

[aviatoreb]

53 minutes ago, ShuRugal said:

My Honda motorcycles from the 70's and 80's all have aluminum blocks with steel liners.  My father has a few from the 50's and 60's.  None of our bikes have ever exploded due to dissimilar thermal expansion rates in the winter.

But it doesn't get that cold in Virginia.

Coldest I have seen around here is -40F, but I have seen -30F for a low at least once during most winters.

[Marauder]

13 minutes ago, aviatoreb said:

But it doesn't get that cold in Virginia.

Coldest I have seen around here is -40F, but I have seen -30F for a low at least once during most winters.

You should host a fly-in for a warm winter month and let them enjoy the balming -20F days.

[ShuRugal]

8 minutes ago, aviatoreb said:

But it doesn't get that cold in Virginia.

Coldest I have seen around here is -40F, but I have seen -30F for a low at least once during most winters.

That is true, but the math on the materials show that the concerns are still fairly insignificant...  certainly within manufactured tolerance.

one of the biggest concerns I saw listed in one of those "articles" was that the thermal shrinkage of the piston would cause excess slop... so let's calculate it.

I don't know the exact bore and piston diameters of our O-360s, so i'm using 3" (7.62 cm) as a general number. 

if we have an aluminum piston that is exactly 7.62 cm in diameter on a standard day, then on a day at -40, it is 7.6103 cm, a shrinkage of .97 mm (.038 in)

If we have a stainless steel cylinder that is 7.63 cm ID on a standard day, then at -40 it is 7.6237, a shrinkage of .067mm.

 

In this case, our gap between piston and cylinder liner has gone from 0.5mm to 0.65 mm, our tolerances changes by 5.9 thousandths of an inch.

 

thoroughly within the "springiness" of the piston rings.

[ArtVandelay]

1 hour ago, ShuRugal said:

My Honda motorcycles from the 70's and 80's all have aluminum blocks with steel liners.  My father has a few from the 50's and 60's.  None of our bikes have ever exploded due to dissimilar thermal expansion rates in the winter.

Agreed, the compressions won’t be good because the piston has shrunk, so you might have trouble starting if your compressions were already low.

[ShuRugal]

Just now, teejayevans said:

Agreed, the compressions won’t be good because the piston has shrunk, so you might have trouble starting if your compressions were already low.

see my post immediately prior to yours (ninja'd you, haha!), the gap changes by less than 6 thousandths of an inch on a -40 day vs a std day.

 

if your piston rings cant spring out enough to take up that extra 6 thou, you need new ones.

[ArtVandelay]

27 minutes ago, ShuRugal said:

see my post immediately prior to yours (ninja'd you, haha!), the gap changes by less than 6 thousandths of an inch on a -40 day vs a std day.

 

if your piston rings cant spring out enough to take up that extra 6 thou, you need new ones.

Your post had same time stamp, well done.

while you have calculator out, my google fu says it’s 4.625” diameter.  

Also, lets talk shock cooling, assume aluminum cylinder head is 200° cooler than the steel barrel, how much is the difference there, assuming 5” outter diameter of the barrel.