Aero-Tips!
A good pilot is always learning -- how many times have you heard
this old standard throughout your flying career? There is no truer
statement in all of flying (well, with the possible exception of
"there are no old, bold pilots.")
Aero-News has called upon the expertise of Thomas P. Turner,
master CFI and all-around-good-guy, to bring our readers -- and us
-- daily tips to improve our skills as aviators. Some of them, you
may have heard before... but for each of us, there will also be
something we might never have considered before, or something that
didn't "stick" the way it should have the first time we memorized
it for the practical test.
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Aero-Tips 12.05.06
A while back there was a series of advertisements for engine oil
that used the tag line, "starting is the worst thing you can do for
your engine." The idea was that most internal engine wear happens
in the moments after start when oil pressure has not come up, and
internal engine parts are rubbing directly against each other.
If your airplane's engine is very cold, oil pressure may take
quite a bit of time to come up enough to distribute oil over
internal engine parts. In extreme cases the oil may b so thick and
gummy that it actually inhibits the smooth motion of engine parts.
This is a prime reason we preheat engines in very cold weather --
anything below about 40 degrees F, according to most
manufacturers.
Preheat the oil
Most preheaters include a flexible hose. Fire up a (potable)
gas-fired heater and shove the hoses into the engine inlets, goes
the standard practice. Run the preheat for five or ten minutes, or
until the lineboy gets too cold and decides the engine is warm
enough. Unplug the preheater, start engines and go.
Trouble is, this process warms only the top part of the engine,
away from the oil pan, and if the preheater is only run a few
minutes it does even less to warm the engine's oil. By far the best
idea is to tow the airplane into a heated hangar to preheat the
engine. Barring that, preheaters work, but the standard practice
described above won't cut it.
To preheat the oil, which is really the objective, put the
preheater hoses not into the engine inlets, but up through the
bottom of the cowling near the oil pan. Run the preheater at least
30 minutes; most preheat instructions recommend longer than that.
If your engine(s) have electric heaters installed plug them in well
before a flight, for most recommend preheating the engine up to
four hours to get a true effect-reduced start-up wear.
Aero-tip of the day: Preheat a cold engine...
and preheat it right.