Th crankcase and sump and made of aluminium, and I wonder if there is a product based on a heating element which could be attached to one of the (many) screws which are all over the place. Such a heater would be left permanently attached, and would be wired to a connector somewhere. A small device could easily dump 100-200 watts into the engine in this way.
Tanis Air Craft : Lycoming 6 cyl premium system: IO-540, TIO-540, LTIO-540 - $1,080.00
Oil Sump Elements : Tanis Air Craft
Cylinder Elements : Tanis Air Craft
Battery Heaters : Tanis Air Craft
Covers - Single : Tanis Air Craft
Various other systems are in common use, including systems that ring each cylinder to heat the engine prior to start. Used with a blanket or cover, these are effective means of heating the engine. Some use a portable generator, some use a propane or other fuel fired heater to inject hot air into the cowl.
Lycoming SI 1505 addresses preheat on Lycoming engines. While I realize that waves, carburetor heat, atmospherics, mixture settings, and of course preheat requirements are different within the geopolitical borders of the UK than the rest of the world, as told to us by genuine UK private pilots, what would happen if we looked to Lycoming for answers regarding Lycoming engines? Is it possible that Lycoming might have some input on the matter, even if it's within the borders of the UK (where physics and of course manufacturer input are artificially suspended)? Let's look:
http://www.tanisaircraft.com/UserFil...20Wx%20Ops.pdf
The use of pre-heat will facilitate starting during cold weather, and is required when the engine has been allowed to drop to temperatures below +10°F/-12°C (+20°F/-6°C for –76 series engine models).
Interesting, that word, "
required." If someone has a dictionary, look it up. See if it still means what it used to mean, will you?
I recall mentioning that a heated dipstick can damage the oil, but let's see what Lycoming has to say:
The use of a heated dipstick is not approved because heat is not distributed throughout the engine, and concentrated heat may damage non-metal engine parts. Proper pre-heat requires a thorough decongealing of all oil.
Interesting. Imagine that. What does Continental have to say on the matter? SIL 03-1 addresses the subject:
http://www.tanisaircraft.com/UserFil...20Wx%20Ops.pdf
Preheating is required whenever the engine has been exposed to temperatures at or below 20° Fahrenheit / -7 degrees Centigrade (wind chill factor) for a period of two hours or more.
There's that word, "
required," again. As we already looked it up, we needn't review it once more.
Continental is a little more direct and forceful with their comments regarding preheating, particularly with their opening warning (
bearing in mind, of course, that aircraft registered in the UK, and the pilots operating them, are exempt from these conditions, and the laws and principles of engine operation, metallurgy, and physics from which these warnings are derived):
Failure to properly preheat a cold-soaked engine may result in oil congealing within the engine, oil hoses, and oil cooler with subsequent loss of oil flow, possible internal damage to the engine, and subsequent engine failure.
Superficial application of preheat to a cold soaked engine can cause damage to the engine. An inadequate application of preheat may warm the engine enough to permit starting but will not de-congeal oil in the sump, lines, cooler, filter, etc. Congealed oil in these areas will require considerable preheat. The engine may start and appear to run satisfactorily, but can be damaged from lack of lubrication due to the congealed oil blocking proper oil flow through the engine. The amount of damage will vary and may not become evident for many hours. However, the engine may be severely damaged and may fail shortly following application of high power. Proper procedures require thorough application of preheat to all parts of the engine. Hot air must be applied directly to the oil sump and external oil lines as well as the cylinders, air intake and oil cooler. Because excessively hot air can damage non-metallic components such as seals, hoses, and drives belts, do not attempt to hasten the preheat process.
Scary stuff, but fortunately, UK residents are exempt, right? These things don't happen in the UK, right?
Standby for more scary stuff (disregard if you're beyond the principles of mechanical motion, because this may not apply to you):
Attempting to start your engine with a partially discharged aircraft battery may result in damage to the starter relay, possible engine kick-back resulting in a broken starter adapter clutch spring.
Engine starting during extreme cold weather is generally more difficult. Cold soaking causes the oil to become thicker (more viscous), making it difficult for the starter to crank the engine. This results in slow
cranking speeds and an abnormal drain on the battery capacity. At low temperatures, aviation gasoline does not vaporize readily, further complicating the starting procedure. Always use an external power source when attempting to start your aircraft engine in cold weather.
"
Always" sounds a lot like that "
required" we read about a couple of times, earlier. Dictionary still available?
More warnings. Be forewarned that the second one is really, really scary. Harry Potter scary. Death, injury, all that. (Don't look those up. You don't want to know).
Do not operate the engine at speeds above 1700 RPM unless oil temperature is 75° Fahrenheit or higher and oil pressure is within specified limits of 30-60 PSI.
Operation of the engine above 1700 RPM before reaching minimum oil temperature may result in engine malfunction, engine failure, injury or death.
I added the last quote there, because I've read posters here telling us before that the engine will never reach operating temperature, and doesn't need to be, before takeoff. If we wait for the temperatures to get up there, we're sometimes told, we'll wait all day, and we can't do that when we're renting. it's too expensive. (Far more expensive than being fit for a casket, for example). Disregard if this doesn't apply to you.
Now, if you're using a combustion heater, Continental will (and does) tell you:
Proper procedures require thorough application of preheat to all parts of the engine. Apply preheated air directly to the oil sump, oil filter, external oil lines, oil cooler, coolant radiator and cylinder assemblies. Continue to apply heat for a minimum of 30 minutes.
If you're using an engine-mounted heater, Continental will (and does) tell you:
Engine mounted preheating systems should include individual cylinder head heater thermocouples, oil sump heater pad and crankcase heater pad. The use of a nacelle blanket will increase the effectiveness of engine preheating.
In other words, heat the whole engine. Go figure. Not just the oil, but the whole engine. If you own a Volkswagen vehicle, you're exempt, because you know better than Continental, and of course if you live in the UK, none of this applies to you, anyway.
Begin preheating of the engine at least 5 hours prior to expected departure. However, do not leave the engine preheating system in operation for more than 24 hours.
Five hours? What? You can't simply show up, jump in, and go? It requires some preparation? Some forethought? Not if you live in the UK, of course, but everywhere else, one may actually have to start preparing for this operation a little early.
Now...there's always the redneck engine heater, using the mechanic's trouble light with the lightbulb, sitting on top of the cylinders around the clock...doesn't actually warm the engine through, but it's cheap, in common use, and in many cases gets left on all the time. Setting aside the fire hazard issue, Continental does have something to say about leaving heaters on all the time. The redneck lightbulb method qualifies as "engine mounted" as it's sitting in the nacelle all the time while in use:
Do not leave an engine-mounted pre-heater system on for more than twenty- four hours prior to flight. Continuous operation of engine-mounted preheater systems may result in aggressive corrosive attack internal to the engine.
The rationale behind this may not seem intuitive to some. Corrosion in oil is largely promulgated by the washing of acids of crankcase walls, chiefly from condensation. Acids settle in the oil and attack bearing surfaces and other areas in the engine, leading to pitting and other corrosion. Additionally, the circulation of the oil around the engine circulates the acidified oil to all parts of the engine, where it can go to work on the components of the engine and propeller when the engine is at rest. Each time condensation forms, the water washes more acid into the oil, and the water itself suborns corrosion as well.
Depending on the nature of the heater in use, heating part of the engine can result in a continual supply of condensation to various parts of the engine. Additionally, continual heating in one part of the engine using electronic means can overheat oil locally, causing chemical changes in the oil in the same way that dipstick heaters tend to do. Another, obvious problem with leaving the heating system in use all the time is the fire hazard.
Regardless of the method of preheating, save for those in the UK who are exempt, we can see that both Lycoming and Continental strongly recommend and even require it: it is not a "
fossil recommendation."