freeman@decwrl.dec.com (Jay R. Freeman) (10/11/90)
From: argosy!freeman@decwrl.dec.com (Jay R. Freeman)
The "solid oil" problem crops up in more conventional aircraft in
wintry temperatures. Only a few people can afford heated hangers for
lightplanes, so pilots and the industry have come up with ingenious
alternatives. External oil-sump heaters are common -- it is said that
a light bulb on an extension cord works well, if you put it under the
sump after shutdown and leave it on all night.
Bush pilots are known to drain the sump into a large tin or drum,
and warm up the oil over a campfire when it is time to get going
again. They say that on particularly brisk days you just drain the
sump into the snow, and pick the oil up in one piece after it sets.
Tended airports in cold places have "preheat" devices, which can
be sent round to chilly airplanes to blast hot air into the cowl for a
while. These gadgets resemble the offspring from a long night of
passion between a flamethrower and an industrial vacuum cleaner.
I recall one amusing personal experience. In December 1971 I
ferried a Bellanca Decathlon from the factory in Wisconsin to the
Pacific Coast. (That's a 180-horsepower two-seat tandem aerobatic
aircraft, with high wing, tailwheel gear, and fabric-covered surfaces
(except for the cowl).) I stopped in Huron, South Dakota, where the
plane cold-soaked at nearly minus 30 Farenheit, all night long. In
the morning I asked for a preheat, but started my preflight inspection
while waiting for the cart to come around.
All went well till I checked the oil. The dipstick was attached
to the inside of the oil filler cap, which screwed on. It was
reluctant to turn. "Thermal contraction and congealed oil," I
thought, and twisted harder. Presently it unstuck, and I unscrewed it
a turn or two. But when I let go momentarily, to shift my grip to
keep turning, the cap screwed itself back up! The oil in the sump had
congealed around the half-inch-wide dipstick, and was applying enough
torque to turn the cap! I finally got it to where I could pull the
dipstick out, and when it broke loose it did so with a most unusual
"pthook" sound. The congealed oil sticking to the dipstick had about
the consistency of red "licorice ropes" or of pretty well-hardened
caramel. It looked delicious, but I had already had breakfast ...
-- Jay Freeman
<canonical disclaimer -- I speak only for myself>ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) (10/15/90)
From: ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) *> The "solid oil" problem crops up in more conventional aircraft in *>wintry temperatures. Only a few people can afford heated hangers for *>lightplanes, so pilots and the industry have come up with ingenious *>alternatives. External oil-sump heaters are common -- it is said that *>a light bulb on an extension cord works well, if you put it under the *>sump after shutdown and leave it on all night. In the book about german ace Erich Hartmann, a captured russian pilot showed the germans how to keep their air- planes startable in the frigid temperatures. The technique was to mix gasoline with the oil! Apparently, after the engine warmed up sufficiently, the gasoline boiled off or evaporated. Do they make multigrade oil for airplanes? Or can you use Mobil 1? ------------------------------------------------------------------------------- Iskandar Taib | The only thing worse than Peach ala Internet: NTAIB@AQUA.UCS.INDIANA.EDU | Frog is Frog ala Peach Bitnet: NTAIB@IUBACS !
geoffm@EBay.Sun.COM (Geoff Miller) (10/16/90)
From: geoffm@EBay.Sun.COM (Geoff Miller) In article <1990Oct15.034029.13416@cbnews.att.com> ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) writes: >In the book about german ace Erich Hartmann, a captured >russian pilot showed the germans how to keep their air- >planes startable in the frigid temperatures. The technique >was to mix gasoline with the oil! Apparently, after the >engine warmed up sufficiently, the gasoline boiled off >or evaporated. Do they make multigrade oil for airplanes? >Or can you use Mobil 1? I don't know how common it is, but apparently there are built-in systems in some reciprocating-engined aircraft that inject avgas into the oil for that purpose. I saw an old training film in the Coast Guard about preparing airplanes for cold-weather storage, and the P-2 in the film had this feature. As for Mobil 1, it's chemically identical to the synthetic oil that's used in U.S. military turboprop aircraft and helicopters, MIL-L-23699. One of our helicopters had a low-oil indication awhile back and made an emergency landing on a baseball diamond at a city park that happened to be next to a Mobil station. The crewman bought a couple of quarts, poured 'em in, and they flew home. (Nonetheless, since Mobil 1 isn't explicitly mentioned by name in the technical manuals as an approved alternate oil, the engine had to be pulled and sent to overhaul.) Geoff -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Geoff Miller + + + + + + + + Sun Microsystems geoffm@purplehaze.sun.com + + + + + + + + Milpitas, California -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
freeman@decwrl.dec.com (Jay R. Freeman) (10/16/90)
From: argosy!freeman@decwrl.dec.com (Jay R. Freeman) In article <1990Oct15.034029.13416@cbnews.att.com> ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) writes: >*> The "solid oil" problem crops up in more conventional aircraft in >*>wintry temperatures. >In the book about german ace Erich Hartmann, a captured >russian pilot showed the germans how to keep their air- >planes startable in the frigid temperatures. The technique >was to mix gasoline with the oil! Apparently, after the >engine warmed up sufficiently, the gasoline boiled off >or evaporated. Do they make multigrade oil for airplanes? >Or can you use Mobil 1? I have heard of the gas-in-oil trick, somewhere. I think possibly that special, built-in hardware for this purpose is called an "oil-dilution system", but I have an uneasy sense that I may be applying a correct name to the wrong apparatus. This flight involved a brand new engine in a brand new plane. The tendancy at such times is to run the beast on a simple grade of uncompounded mineral oil, with no fancy additives. I am not sure why. Many lightplanes are regularly run on very simple oils -- I think the idea is that many additives break down into things that gum up or damage the engine, and high-reliability in *the* engine is of course a paramount consideration. Light airplanes used for hire get an oil change at least every hundred hours of operation, in any case. Lightplane engines tend to run somewhat hotter than (say) automobile engines, and when they are run it is typically for several hours at a time, at a high percentage of peak power. One weight of oil is likely sufficient for normal operation at equilibrium engine temperature, without regard to ambient air temperature. And given the relatively widespread availability of (eg) preheaters, there seems to be no real need to seek out multi-weight oils just for starting. It has been twelve years since I have been active as a pilot; perhaps there have been some changes in the technology since then. -- Jay Freeman <canonical disclaimer -- I speak only for myself>
joefish (joefish) (10/19/90)
From: joefish (joefish) There has never been much of a problem with oil in reciprocating engines (as far as I know). In 1947 I did AT-6 maintenance at Randolph Field Texas and they were equipped with oil dilution valves that allowed holding a switch in the cockpit for so many seconds to pump gas into the sump just before shutting off the engine. As far as I can remember, the same setup was on every type plane that I preflighted (B25, B26, A26, B29, B17, P61, P51, etc) but I didn't need oil dilution with the weather at Keesler Field, Biloxi, Miss. Joe Fischer joefish@disk
ron@hpfcso.fc.hp.com (Ron Miller) (10/19/90)
From: ron@hpfcso.fc.hp.com (Ron Miller) Re; congealed oil > > In the book about german ace Erich Hartmann, a captured > russian pilot showed the germans how to keep their air- > planes startable in the frigid temperatures. The technique > was to mix gasoline with the oil! Apparently, after the > engine warmed up sufficiently, the gasoline boiled off > or evaporated. Do they make multigrade oil for airplanes? > Or can you use Mobil 1? > Iskandar Taib | The only thing worse than Peach ala I got a look at a NATOPS manual for a T-28 Trojan that my father was flying for proficiency hours while at a desk job in Washington. The airplane had an oil dilution system for cold starts of the monster radial engine. Seemed kind of wierd, and was undoubtedly a little hard on the equipment but apparently is a known solution to the problem. I presume that the gasoline evaporates and leaves the oil back at normal viscosity once the oil is up to temp. I also recall in Martin Caidin's book about the Ju-52 trimotor German airplane he owns that he talks about the equipment in the airplane that was installed for operations in the Russian winter on the Eastern Front. My opinion is that only a government funded military can afford the replacement and maintenance that comes with gasoline dilution. The rest of us use electric or kerosene block heaters. (I use an electric block heater on my jeep and I've used kerosene preheaters on light airplanes for starts at 0F.) Ron Miller
scw@ollie.SEAS.UCLA.EDU (Stephen C. Woods) (10/24/90)
From: "Stephen C. Woods" <scw@ollie.SEAS.UCLA.EDU> >From: argosy!freeman@decwrl.dec.com (Jay R. Freeman) [...] Mobil 1? > >I have heard of the gas-in-oil trick, somewhere. I think possibly >that special, built-in hardware for this purpose is called an >"oil-dilution system", but I have an uneasy sense that I may >be applying a correct name to the wrong apparatus. Some Cessna C-172 and C-182 modles have this option. It is specificly for cold weather operations. >This flight involved a brand new engine in a brand new plane. The >tendancy at such times is to run the beast on a simple grade of >uncompounded mineral oil, with no fancy additives. I am not sure why. Durring the engine break in period you run 'straight' mineral oil because it has the MOST friction, and LEAST lubricating ability. The idea is to get the rings to wear a bit so that they fit snugly. Typically you rin straight oil until the oil consumption (somewhere in the order of a quart every 3-4 hours of so) stabilizes. After the break-in you can (and usually do) run a multi-grade oil. >Many [...] airplanes used for hire get an oil >change at least every hundred hours of operation, in any case. Uhmmm isn't that every 50 hours (aproximates 3000 miles in a car)? It seems to me that both Lycoming and Continetal specify 50 hours between Oil changes unless (multiple qualifiers...). >Lightplane engines tend to run somewhat hotter than (say) automobile >engines, and when they are run it is typically for several hours at a >time, at a high percentage of peak power. oThis is why it is important to change the oil regularly, oil begins to break down fairly quickly at higher temperatures, also as oil is run through the engine, mechanical shearing breaks down the long chain polymiers that help oil hold its viscosity at higer temps. Shouldn't this discussion be in sci.aviation/rev.aviation? -- ----- Stephen C. Woods; UCLA SEASNET; 2567 BH;LA CA 90024; (213)-825-8614 UUCP: ...!{ibmsupt,hao!cepu}!ollie}!scw Internet:scw@SEAS.UCLA.EDU