What's the truth about ground running?

[Shadrach]

On December 24, 2015 at 5:19 PM, Mooneymite said:

From the above link:

http://thenewfirewallforward.com/linked/centri_lube_info.pdf

>>> Buldoc, the engine rebuilder, also strongly recommends not leaving any engine preheater on for lengthy periods, i.e. days or weeks. Clearly warm air holds more moisture than cold air. <<<

 

I think that makes little sense. What's the difference between keeping the engine bay at a constant 70df or keeping the whole plane in a heated hangar at 70df?

Edited December 27, 2015 by Shadrach

[Shadrach]

On December 24, 2015 at 0:10 PM, M20F said:

Good article on corrosion in particular how humidity plays a role in corrosion.  A hanger doesn't change the humidity content of air.

http://www.aviationpros.com/article/10387461/corrosion-how-does-it-affect-the-internal-engine

No, but having standing water in a sealed hanger will make for a more humid environment.

Edited December 27, 2015 by Shadrach

[M20JFlyer]

I have drank the cool aide from cont. and lycom for soo long ..soo many years that ... During my 53 years  flying AIR cooled ICE aluminum engines I am told that "WEIGHT " is considered such an enemy of designing with metallurgy conducive to enduring what an ICE engine spu's ..but what a 1940's Chevy six can endure ---IT's just my ignorance . That Chevy engine does not have to perform in cold, hot , high elevation high RPM ,thinner atmosphere, turning an approx 50 to 70 inch flywheel...ever seen video of pikes peak hill climb

for fear of being labeled an idiot " Trumpster" I should cave in and say NO lyc or Connie engineers have ever exceeded the function of a 1940's designed Chevy six cylinder with a60lbs clutch plate in the last 60 years -

- I call Bullshit--that an engine costing north of 60K for a 4 cylinder -- to plus 90K for basic 6 banger ..Really !! Has no inherent rust protection no designed option or thought of some fog oriface(s) to lube my fragile cam or cylinder walls with an aerosol loaded with "metal surface" preserving lube ( similar to corrosion X or ??) dispersed at 20-40 microns in the cavity of the engine .. knowing the vast majority of SE ENGINES suffer lapses of usage detrimental to safe longevity ... Really, a fogging option would have no merit considering rust is the alternative

I will concede that I get a high "every time" I depart my local Airport looking down on roof tops .. And that for the first 40 to 120 seconds those roof tops will interfere with a successful day flying if I am not marginally lucky ...or put another way I would really miss the opportunity to microscopically inspect my oil filter each 25-50 hours of operation ..as an inhibiting method to raise my relative numerical odds..that one system of my tough little engine ( the camshaft ) will not kill  it's promise - to not fail me now.  

that to be safe & successfull today the leading GA mfg... of single engine AIRPLANE adds a ballistic chute special seating, enhanced cabin supports to remain successful in the single engine GA fray. Those parts that system are an affordable weight that would never be allowed in the power plant design of a modern airplane

Or just saying ..my grand kids ask...Gpa .. How come we wear bike helmets, and put this flame thingy on when we take off ..other people we talk to don't need it? Yes I understand NO flying activity is more prone to interruption than full power departure and more headlines read shortly after leaving the airport.

YES I KEEP FLYING understanding flying is not "more full of risk " today than 60 years ago , that statistically I am safer in the air than on horseback , and the enjoyment of flying far exceeds any other adventure I choose to enjoy

pls let the game begin yeah I know this rant was all the result of flying LOP

And ..what are the odds flying mag will ask for permission to include this tantrum in an upcoming issue

[MyNameIsNobody]

I FIND GRUMPY OLD OBSESSIVE WORRIERS AMUSING...

[Hector]

On December 24, 2015 at 0:10 PM, M20F said: Good article on corrosion in particular how humidity plays a role in corrosion.  A hanger doesn't change the humidity content of air.

http://www.aviationpros.com/article/10387461/corrosion-how-does-it-affect-the-internal-engine

No, but having standing water in a sealed hanger will make for a more humid environment.

Exactly. Go to my airport early in the morning and all planes parked outside are dripping water from everywhere. My airplane sitting inside even a crappy hangar that is not well sealed is nice and dry. I have no doubt that the humidity inside my hanger may be high quite often but at least I'm not exposing my plane to the equivalent of a rain shower every night.

[M20F]

2 hours ago, Hector said:

Exactly. Go to my airport early in the morning and all planes parked outside are dripping water from everywhere. My airplane sitting inside even a crappy hangar that is not well sealed is nice and dry. I have no doubt that the humidity inside my hanger may be high quite often but at least I'm not exposing my plane to the equivalent of a rain shower every night.

It doesn't really make much of a difference.  The inside of your engine, the spar, etc. doesn't get rained on anymore sitting outside then it does sitting in a hanger.  A hanger can help some with surface corrosion but that is more from shielding the plane from acids and other chemicals in the rain as opposed to the actual water itself.  Surface corrosion is a non-event and easy to fix, spar/engine corrosion not so much.

Humidity is the issue and it isn't blocked by hanger doors (short of hermetically sealed ones).

[Hector]

2 hours ago, Hector said: Exactly. Go to my airport early in the morning and all planes parked outside are dripping water from everywhere. My airplane sitting inside even a crappy hangar that is not well sealed is nice and dry. I have no doubt that the humidity inside my hanger may be high quite often but at least I'm not exposing my plane to the equivalent of a rain shower every night.

It doesn't really make much of a difference.  The inside of your engine, the spar, etc. doesn't get rained on anymore sitting outside then it does sitting in a hanger.  A hanger can help some with surface corrosion but that is more from shielding the plane from acids and other chemicals in the rain as opposed to the actual water itself.  Surface corrosion is a non-event and easy to fix, spar/engine corrosion not so much.

Humidity is the issue and it isn't blocked by hanger doors (short of hermetically sealed ones).

I was referring to airframe corrosion, and no, humidity inside a hanger and having your airplane exposed to the elements outside is NOT the same. The degree to which the airframe is exposed and the likelihood that running water will find its way through lap joints, loose rivets, access doors, windows, etc. is much greater when an airplane sits outside.

[ryoder]

On 12/23/2015 at 0:03 AM, Piloto said:

Never seen this in my hangar. This could be caused by a sudden high temp drop at night and poor sealing of the hangar doors. Mine has rubber seals all around. Overnight temps drop here in Florida are not as high as in Texas.

José  

When my Mooney was in a shade hangar at KCLW it had so much dew on it in the morning it was useful as part of my preflight washing procedure.  I just sopped the water off and I had a sparkly clean airplane.

Now that I am in a hangar in KZPH I don't see that dew anymore.  The prop does get some crystals on it after over a week of sitting so there is some humidity but not enough to coat the airplane.  

Maybe the hangar just moderates the temperature swings so condensation doesn't have a chance to form.

[pinerunner]

One more thought occurred to me with respect to this ground running business (mainly for planes that have set a spell). I remember reading and have observed that if you fill the oil up to the max it tends to use up the the first couple of quarts faster. I don't think  oiling through the normal oil channels could cause this. That leaves me assuming that the crankshaft actually dips into the oil in the sump and flings in around, making a LOT more oil in the oily fog which then goes out the vent pushed by blow-by gases (you can't have zero blow-by). 

I'm thinking I want it at 6 quarts if I have been flying it (to not use oil so fast and not dirty up my belly and need to clean it so much) a lot but if it's been sitting I'll top it off and be glad to have to wash the belly. The hope is that the camshaft would be getting hit with more oil sooner,  minimizing the time its getting less than ideal lubrication.

[pinerunner]

On 12/22/2015 at 11:07 AM, DXB said:

I have a  condensation problem in my hangar.  Crappy asphalt floor that's wet after rain, then evaporates into trapped air in the hangar during warmth of the day, condenses onto the plane with cooling at night.  No venting mechanism at all. Cheap steel tools on my shelves rust rapidly.   Do you vent the fan to the outside?  Seems like you've gotta get the moist air out somehow during the day so air in hangar is no wetter than ambient humidity outside.   

The condensation thing is just a little more complicated than what's been implied so far. The notion that's been missing is this. Condensation forms faster on colder surfaces when you get down near the dew point. You don't want your plane to be the coolest thing in the hangar and the metal plane tends to radiate heat away faster and have a lower heat capacity (so it cools more for the same heat loss)  than the concrete or asphalt floor. Just a little extra heat may be all takes to make your Mooney stop being a condensation magnet, even in an unheated, non air-conditioned hangar.

Lucky me. I've got an electric outlet next to my M20E and they don't even charge me for the electric bill (though they might think about it if they knew everything I was thinking of doing with it).

[cnoe]

One more thought occurred to me with respect to this ground running business (mainly for planes that have set a spell). I remember reading and have observed that if you fill the oil up to the max it tends to use up the the first couple of quarts faster. I don't think  oiling through the normal oil channels could cause this. That leaves me assuming that the crankshaft actually dips into the oil in the sump and flings in around, making a LOT more oil in the oily fog which then goes out the vent pushed by blow-by gases (you can't have zero blow-by). 

I'm thinking I want it at 6 quarts if I have been flying it (to not use oil so fast and not dirty up my belly and need to clean it so much) a lot but if it's been sitting I'll top it off and be glad to have to wash the belly. The hope is that the camshaft would be getting hit with more oil sooner,  minimizing the time its getting less than ideal lubrication.

Even with 8 qts the cam sits high and (eventually) dry once the engine's shut down. After a period of time (insert your best guess here) the oil drains into the pan further exposing internal surfaces. I'm just regurgitating what I've read and been told.

But note that Lycoming says that 2 qts is all it takes to lubricate the engine. So 6 qts seems like enough to me for most of my flights, even if it's sitting for 3-4 weeks. Anything longer than a month and I'm going to pickle it (in my humid area anyway).

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[N601RX]

2 hours ago, pinerunner said:

One more thought occurred to me with respect to this ground running business (mainly for planes that have set a spell). I remember reading and have observed that if you fill the oil up to the max it tends to use up the the first couple of quarts faster. I don't think  oiling through the normal oil channels could cause this. That leaves me assuming that the crankshaft actually dips into the oil in the sump and flings in around, making a LOT more oil in the oily fog which then goes out the vent pushed by blow-by gases (you can't have zero blow-by). 

I'm thinking I want it at 6 quarts if I have been flying it (to not use oil so fast and not dirty up my belly and need to clean it so much) a lot but if it's been sitting I'll top it off and be glad to have to wash the belly. The hope is that the camshaft would be getting hit with more oil sooner,  minimizing the time its getting less than ideal lubrication.

The crank doesn't get anywhere near the oil in the sump. The 3 slots in the center is where the oil drains back into the sump.  The round hole in the upper right is the oil fill tube opening.  Unless you have a cam oiling mod the only oil the cam gets is what comes from around the rod and main bearings and is slung off the crank as well as what is splattered around from the pistons via the piston oilers.

[bonal]

Very nice of you to pull your engine to show us how it works.

[N601RX]

1 minute ago, bonal said:

Very nice of you to pull your engine to show us how it works.

This was from a few years ago when we overhauled it.  I regret not making more pictures, but never seemed to think about it until the end of the day.