engine heaters - leave them on all winter?

NoHeat

NoHeat

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I've heard two sides of the debate, for those of us who live where it's cold in winter:
  • leave engine heaters on all the time in winter
  • vs. turn them on only within 24 hours of flying

Our club follows the simple practice of plugging them in all winter, and throwing a sleeping bag over the cowl to keep the warmth in.

Continental differs. They say:
WARNING
Do not leave an engine-mounted pre-heater system on for more than twenty- four hours prior to flight. Continuous operation of engine-mounted pre- heater systems may result in aggressive corrosive attack internal to the engine.*​

I'm wondering exactly how Continental thinks corrosion will occur. It seems to me that it's the *cooling* of a warm engine that will cause a problem with water vapor condensing, and if your engine stays warm all the time until just before you start it, when exactly does the water get into the engine to cause "corrosive attack"?

* See p. 45 of this Continental booklet:
http://www.insightavionics.com/pdf files/Continental.pdf
 
I believe the reasoning is that, if in sub-freezing temps, the warm moist air inside the case will allow condensation to occur at the various cooler parts, with resultant moisture running down inside the engine, and further, the moisture in the air itself will attack exposed surfaces.

Just warm it up a reasonable time before flight.

Now, for a light school's fleet, flying very often, this is likely all not an issue, and leaving the engines heated all the time makes it less likely that someone will forget to warm and engine and do damage in that way.
 
Okay, so the idea is still that cooling is what's important, but cooling can happen because of air movement from a warm spot to a cold spot in the engine -- I think I can picture that. Thanks.
 
What Spike said... for a club plane flying several days per week, nothing wrong with leaving it plugged in all the time - and I agree there is more damage potential from a pilot not properly warming it up than from condensation.

Even if it sits for two days, and some condensation forms it will all get blown out on saturday when that thing is flying 4-5 hours
 
When I use the heater on my plane I open the oil filler so the warm moist air has an exit and is not trapped inside the engine.
 
I have mine set on an inexpensive timer so it turns on Friday evening and off Sunday night. I'd rather have it on a phone-activatable rig, but my electronics mojo is insufficient to the task of setting one up.
 
dillardrg said:
When I use the heater on my plane I open the oil filler so the warm moist air has an exit and is not trapped inside the engine.
Click to expand...

Very little statically breathes out through that cap. You're not really doing anything.
 
Corrosion rates depend on temperature - the higher the temperature the faster things corrode (don't believe me - look it up yourself).

What would be the advantage of leaving them on all the time?
 
BurtM said:
It looks like that box has what I call phone line connector jacks...

What would we do for our hangar that has power but no phone line available?
Click to expand...

http://www.dealextreme.com/p/gsm-ce...iversal-socket-ac-220v-3-flat-pin-plug-110202

Unlocked GSM sim card from whatever cell carrier does that these days and a text message or a phone call to it.

That one is just from a Google search and looks a little cheesy, but there's lots of models of those. GSM remote switch.

There's also ones with Ethernet ports if you can get a routable public IP address to it somehow. You can kinda go overboard with those.... Multiple switched ports and stuff...

http://www.digital-loggers.com/lpc.html
 
The water is already in your engine when you shut it down, How will it get out of the engine when you heat it? There is no circulation thru the engine while setting, speciality when it is wrapped with a blanket.
Water will be in the form of steam when running, or while the engine is hot. That water will condense in the coldest portion of the engine as the engine cools and will drain down to the sump as the engine sets. It will sink in the oil and won't cause corrosion while covered.

Heat the oil and the water will boil out and start the cycle again, over and over while the heater is on.

Things to remember :
Lycoming's oil filler tube is small and enters the cases at the oil sump, too low to allow the hot water vapors out, so the water condenses on the upper case and cam/lifters.
 
denverpilot said:
http://www.dealextreme.com/p/gsm-ce...iversal-socket-ac-220v-3-flat-pin-plug-110202

Unlocked GSM sim card from whatever cell carrier does that these days and a text message or a phone call to it.

That one is just from a Google search and looks a little cheesy, but there's lots of models of those. GSM remote switch.

There's also ones with Ethernet ports if you can get a routable public IP address to it somehow. You can kinda go overboard with those.... Multiple switched ports and stuff...

http://www.digital-loggers.com/lpc.html
Click to expand...

Thanks for the additional info. I grew up when we kept a dime in our loafers (behind the penny) to use the pay phone. And more often than not, the pay phones had a dial...

Anyway, to have an interface box that recognizes a GSM device, requires having a GSM device, which I'm guessing is an old cell phone, right?
 
BurtM said:
Thanks for the additional info. I grew up when we kept a dime in our loafers (behind the penny) to use the pay phone. And more often than not, the pay phones had a dial...

Anyway, to have an interface box that recognizes a GSM device, requires having a GSM device, which I'm guessing is an old cell phone, right?
Click to expand...

Nah, the "cell phone" guts are already in the device. You just need a SIM card (all GSM phones have one) tied to a cell carrier of your choice, and pay for adding that device to your account if you're already on a GSM carrier, or paying for a new cheap account (something pay-as-you-go if you can find it from a carrier seems appropriate here... A text message may cost you $.50 each time you send one to it or something like that), and pop that SIM into the device, if you're on a carrier that doesn't do GSM for your daily driver cell phone.

It won't be free and you'll have a monthly charge, but it does fit the bill if you really want to have the remote power switch accessible via a phone call or text message.

The phone number moves with the SIM so it can even start out in a cheap phone and be moved if the SIM is truly "unlocked", and you're all set. Then just keep paying the bill. Carriers may or may or charge extra for an unlocked SIM not tied to a true phone. You will have to shop that around a bit for appropriate carriers that have coverage at your hangar.

Some remote power devices I've seen will respond to just ringing the number without it actually answering as a way to avoid phone charges, but it would leave me wondering whether it had really turned on the power or not. I'd prefer to pay for the SMS/text message or the brief phone call to send it a command and have it respond in some meaningful way that confirmed it had switched on.

Plus ringing and not answering would also be the failure mode of the hangar had a power outage.

If we had power at our hangar I'd have something set up to do it. Not sure I'd remotely turn stuff on like building heat after seeing what happens when a Cessna bladder tank ruptures in a hangar though. That was one huge fire hazard with fuel all down the side of the aircraft.

I don't think a properly installed heater in the engine compartment is high-risk, but an electric space heater out in the hangar could be. Your call.

Another thing to watch is the current (amperage) rating of the switch. Make sure not to exceed the load rating. Electric heaters of any sort might pull a lot of current when activated. As I said, that one I linked to was just a quick example from Google and it said 10 Amps. Most U.S. 110V outlets are rated at 15A. If the heater needs 12A, you'd need a different model.

Personally I'd also like to know if the switching was solid-state or done with a relay. If a non-sealed relay, there's a tiny spark when the contacts close inside and fuel fumes plus oxygen plus spark... well, don't let fuel fumes build up in your hangar. But see comments above about bladder tank rupture... The hangar was quite smelly with spilled fuel, too.

Most of us don't have automatic fire suppression systems in our hangars. Keep that in mind.
 
Leaving constant heat on an engine that is started once a week, (or less) in an cold, damp hangar, is bad - pure and simple... I cannot think of a better way to guarantee needing a new cam...

The phone stuff for signalling has come a long ways in the past few years... Try here...
http://www.gsm-auto.com/
 
My Reiff draws enough current that all I have to do is turn it on 1-2 hours before flight and it's plenty warm enough to start the engine safely. Overnight and it's really toasty -- to the point where it can be like starting the engine warm.
 
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