Preheating engines: Airplane engines versus auto engines

This time of year here in the Northeast US I always preheat my Bonanza's
IO520 engine with a Tanis heater and an insulated cowling/prop cover as it
sits in an unheated t-hangar. The result is that the oil temperature at
startup is around 105 degrees F, even if the outside air temperature is as
low as -15 degrees F.

Monday night I arrived at my t-hangar to discover that at some point during
the day the line person accidentally pulled out the plug connecting the Tanis
heater to the small extension cord I use to extend the plug to the outside of
the cowling cover, so the aircraft had not been preheating. Outside and
inside temperatures were both a cold 25 degrees F.

Given any other day, I would have plugged the aircraft back in and scrapped
the flight but in this case I had an Angel Flight patient waiting in another
city for my arrival and I was already late. Thus I made the painful decision
to start up the aircraft and allow it to low idle until the oil heated
thoroughly. A small consolation is that the engine had been recently filled
with fresh Exxon Elite oil. To my relief the aircraft started right up.

I know what I did has negative long term repercussions on my engine's health
and I have already derived a tool to lock the two cords and prevent this
accidental unplugging from happening again. However, this leads me to
question the differences between aircraft engines and auto engines:

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

--
Peter

In a previous article, "Peter R." said:
Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?



Aircraft engines are air cooled, auto engines are liquid cooled.

The following is what I was told when I was driving a Volkswagen Beetle,
and the experts were saying that you needed to let the beast idle for at
least 5 minutes in the winter:

Liquid cooled engines stay in a very narrow temperature range while
operating, so are built with very tight tolerances, but air cooled engines
have more slop because they get both hotter and colder than liquid cooled
engines. Also, they are cooled primarily by the engine oil. Because of
that, you need to preheat the engine enough that the oil is spread around
and everything has warmed enough that the pistons are making good contact
with the cylinder walls.


--
Paul Tomblin http://blog.xcski.com/
"The day Microsoft makes something that doesn't suck is probably the day they
start making vacuum cleaners" - Ernst Jan Plugge

"Peter R." wrote
...
...........................................
Outside and inside temperatures were both a cold 25 degrees F.

Given any other day, I would have plugged the aircraft back in and
scrapped
the flight but in this case I had an Angel Flight patient waiting in
another
city for my arrival and I was already late. Thus I made the painful
decision
to start up the aircraft and allow it to low idle until the oil heated
thoroughly. A small consolation is that the engine had been recently
filled
with fresh Exxon Elite oil. To my relief the aircraft started right up.

I know what I did has negative long term repercussions on my engine's
health
................................................. .....
Peter



This is joke post, right????
You're killing your engine because you started it at 25
deg???????????????????????????????????
ROTFLMAO
I'm sorry, I'll shut up now.

On Dec 19, 9:35 am, (Paul Tomblin) wrote:
In a previous article, "Peter R." said:

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

Aircraft engines are air cooled, auto engines are liquid cooled.

That may affect the time it takes for the oil to heat up but certainly
both engines start at the same temp. I think the question relates to
the lubrication ability of sluggish oil at start. In addition, I'm not
sure that an aircraft engine at idle really displaces much more heat
than a car engine with the thermostat closed in the cold. How much air
really moves over the cylinders of an idling aircraft engine?

-robert

Peter R. wrote:

--- clip clip --


Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

Here in the north of Europe We'll pre-heat our cars if
possible, if the temperature goes below +5 C (whatever
it is in F, around 40?).

You can force an engine to start even at -30 C, but it
means that the poor thing runs some time practically
dry of lubrication.

--

Tauno Voipio (CPL(A), flying OH-PYM, PA28RT-201T)
tauno voipio at iki fi

Peter R. wrote:

Given any other day, I would have plugged the aircraft back in and scrapped
the flight but in this case I had an Angel Flight patient waiting in another
city for my arrival and I was already late. Thus I made the painful decision
to start up the aircraft and allow it to low idle until the oil heated
thoroughly. A small consolation is that the engine had been recently filled
with fresh Exxon Elite oil. To my relief the aircraft started right up.

I think you made the right judgment call.

The engine life is more dependent on your long-
term level of care than for a single instance
of pressing the limits.

BTW, a simple overhand knot in the power cord
where the heater plug and the extension cord
mate will prevent someone from inadvertently
unplugging them.

I know what I did has negative long term repercussions on my engine's health
and I have already derived a tool to lock the two cords and prevent this
accidental unplugging from happening again. However, this leads me to
question the differences between aircraft engines and auto engines:

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

On 12/19/2007 1:09:15 PM, Jim Stewart wrote:

BTW, a simple overhand knot in the power cord
where the heater plug and the extension cord
mate will prevent someone from inadvertently
unplugging them.

Unfortunately no room for an overhand knot. There is no slack at all in the
Tanis heater-side plug, as it is secured right at the plug to the (IIRC)
support that also holds the fuel lines.

--
Peter

On 12/19/2007 12:39:10 PM, "gpaleo" wrote:

This is joke post, right????

Yes, it's a joke. You can go back to bed now.

--
Peter

On Dec 19, 12:21 pm, "Peter R." wrote:
This time of year here in the Northeast US I always preheat my Bonanza's
IO520 engine with a Tanis heater and an insulated cowling/prop cover as it
sits in an unheated t-hangar. The result is that the oil temperature at
startup is around 105 degrees F, even if the outside air temperature is as
low as -15 degrees F.

Monday night I arrived at my t-hangar to discover that at some point during
the day the line person accidentally pulled out the plug connecting the Tanis
heater to the small extension cord I use to extend the plug to the outside of
the cowling cover, so the aircraft had not been preheating. Outside and
inside temperatures were both a cold 25 degrees F.

Given any other day, I would have plugged the aircraft back in and scrapped
the flight but in this case I had an Angel Flight patient waiting in another
city for my arrival and I was already late. Thus I made the painful decision
to start up the aircraft and allow it to low idle until the oil heated
thoroughly. A small consolation is that the engine had been recently filled
with fresh Exxon Elite oil. To my relief the aircraft started right up.

I know what I did has negative long term repercussions on my engine's health
and I have already derived a tool to lock the two cords and prevent this
accidental unplugging from happening again. However, this leads me to
question the differences between aircraft engines and auto engines:

Why is it that here in the Northeast US seemingly no one preheats their
automobile engine before start-up in very cold temperatures? Is the long-term
damage the same for both autos and aircraft engines? If so, why do you
suppose auto owners don't typically do this? Is it because that most auto
owners do not keep their cars very long?

--
Peter

My understanding is that the _oil_ is different, not the engine. Most
piston aircraft engine oils gel at higher temperatures than do oils
for automotive engines. Or at least that is what I was told by my
instructor when I was training up in the high country.

Don't be relieved that the engine started. Be relieved that there
isn't anything ferrous in the oil screen next annual inspection.
Might ask your neighborhood FBO to use one of their portable heaters
next time around :-)

-Psy

On 12/19/2007 1:51:18 PM, " wrote:

Might ask your neighborhood FBO to use one of their portable heaters
next time around :-)

I have read in several different mags that those portable heaters only warm
the cylinders and not the bottom end (cam shaft) where the heated oil is most
important during the short time most FBOs run the units. Consequently it is
somewhat a waste of time and energy to use that type of heater.

--
Peter