Makeshift engine heater?

flyingcheesehead

flyingcheesehead

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iMooniac
It's gettin' cold here in Wisconsin, and while I'd love to just put a Reiff preheater on the Mooney, it seems a somewhat foolish thing to do since the plane could be sold any day to someone in a warm climate that'd have no use for the preheater (it was *this close* to going to Florida already).

Cost for a preheat at the home 'drome is $40 + tax, so that Reiff would probably be paid for by the end of winter.

I'm just wondering if there's a reasonable way to take a decent space heater and build a duct for it out of some flexible material, put it underneath the plane and have it blow warm air into the engine compartment via the cooling air exits underneath the plane.

Has anyone done such a thing? What materials would be best for the ducting? What's the best type of space heater, and what types should be avoided if any? Is this a safe thing to do in a hangar? Are there any other solutions?

Thanks!

Kent
 
Not meant for unattended use, but our preheater is one of those construction torpedo heaters with dryer vent duct. The stuff that goes from the back of the dryer to the wall.

Works fine, just don't be dumb and grab the duct without a glove on to remove it. ;)
 
In the days before I had a heated hangar, I would drape a blanket over the cowl of the Comanche I then owned and put a small "milkhouse" heater on the floor just behind the nose gear facing aft. It was not touching nor near anything that would burn, and kept the area inside the blanket around 45-50 degrees when the outside temp was in the teens. The heater had a tip over and overheat switch. Never had any issue.
 
Before I had the oil pan heater installed, I used a shop light w/ 100w bulb located inside the bottom cowl with an insulated cowl cover (inherited from the person who previously had the hanger and sold their C172) Before the cowl cover, I used an old sleeping bag.
 
flyingcheesehead said:
It's gettin' cold here in Wisconsin, and while I'd love to just put a Reiff preheater on the Mooney, it seems a somewhat foolish thing to do since the plane could be sold any day to someone in a warm climate that'd have no use for the preheater (it was *this close* to going to Florida already).

Cost for a preheat at the home 'drome is $40 + tax, so that Reiff would probably be paid for by the end of winter.

I'm just wondering if there's a reasonable way to take a decent space heater and build a duct for it out of some flexible material, put it underneath the plane and have it blow warm air into the engine compartment via the cooling air exits underneath the plane.

Has anyone done such a thing? What materials would be best for the ducting? What's the best type of space heater, and what types should be avoided if any? Is this a safe thing to do in a hangar? Are there any other solutions?

Thanks!

Kent
Click to expand...

If you have electricity in your hangar then your options are limitless...

I use this. http://archeat.com/mm5/merchant.mvc...A&Product_Code=AO-455FGT&Category_Code=FAAAIR

Along with a old comforter off the bed to hold in the heat..

In your case, three preheats will pay for the pad.. YMMV.
 
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I just snuggle in close with mine, in the spoon position. Sometimes I'll rest my hand on her fuselage, other times cupped around the cowling.

MAKG is right though about unattended space heaters.
 
denverpilot said:
Not meant for unattended use, but our preheater is one of those construction torpedo heaters with dryer vent duct. The stuff that goes from the back of the dryer to the wall.

Works fine, just don't be dumb and grab the duct without a glove on to remove it. ;)
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He's allegedly trying to sell this plane. That means, when the duct curls or blackens the cowl paint, he can't sell the plane.

Oh wait! maybe that's operative here....:wink2:
 
No need to conjure something up when the real thing is almost free. Go to your local TSC or farm&fleet store, buy a silicon pad heater for $15 and stick it on the bottom of your oil pan.
 
JHW said:
No need to conjure something up when the real thing is almost free. Go to your local TSC or farm&fleet store, buy a silicon pad heater for $15 and stick it on the bottom of your oil pan.
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+1 get a katz heater with the 3M aluminum sticky backing..best $20 you ever spend. I woud stick with the 100W one for 4-7 quarts
Thermocube wall plug in will automatically turn off the heater above 45 and turn it on below 35
 
JHW said:
No need to conjure something up when the real thing is almost free. Go to your local TSC or farm&fleet store, buy a silicon pad heater for $15 and stick it on the bottom of your oil pan.
Click to expand...

Jeff,

I hate to start this thread down the wrong direction, but this needs the a few additional comments.

If only an oil pan heater is used, is is almost certain that it will not heat the entire engine above the dew point. This turns the cold portions into a terrarium as the water vapor released from the oil condenses in those cooler places.

Not necessarily a huge problem if one turns on the heater for a few hours and flies the plane, but turning on a stick-on oil heater and leaving it on out of convenience is not something I would do to my engine in a northern or damp climate. Particularly in a Lycoming 4 banger with the cam parked way up in the top of the terrarium tent.


My half baked compromise in the Mooney is a pair of 100 watt mechanics drop lights, one tucked up in each cowl flap. An insulated blanket on top of the cowl, cowl plugs in, and a hooded sleeping bag zipped over the prop (another big heat sink attached to the crankshaft).

Makes it look like a homeless bum, but I want the entire case, cam, and crankshaft warm and above the dew point.

I also make every attempt to fly it after I turn on the heat, which I can do remotely.
 
Are you sure that's a problem? Aluminum is a very good heat conductor.

Somewhat weak evidence would be condensation on the oil dipstick.

The dewpoint is below outside ambient temperature, or else the temperature would be higher (and it would be foggy).

You can make your engine into a still if you overdo the heat and start to boil water out of the oil (there is always some).
 
My half baked compromise in the Mooney is a pair of 100 watt mechanics drop lights said:
This is exactly the way I keep my entire engine at 50+ all winter long, but with one 100 watt bulb. I will pay for it away from home if needed.
Click to expand...
 
MAKG1 said:
Are you sure that's a problem? Aluminum is a very good heat conductor.
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Depends. Aluminum conducts heat very well both ways. If the top half of the engine is well ventilated the cowl is poorly insulated, there are a whole range of ambient temperatures that will keep upper half of the engine cool.

What is that engine is engineered to do??? Radiate as much heat as possible off of all those fins and cool the top half down!

MAKG1 said:
Somewhat weak evidence would be condensation on the oil dipstick.

The dewpoint is below outside ambient temperature, or else the temperature would be higher (and it would be foggy).
Click to expand...

Think about what is going on inside the engine. It is a nearly closed space with a moisture generating source at the bottom (the oil). The dew point inside is independent of what is going on outside. If I raise the oil temperature to, say, 75 degrees, I can have a nice, balmy, and humid environment just above the surface of the oil with an entirely different dew point than what is going on outside. That warm, humid air is going to rise. Again, there are a whole range of ambient temperatures that are going put that cam below the localized dew point.

Think of it this way... if I pour an inch of warm coffee into a Starbucks cup with a flimsy plastic lid and take it outside on a cold day, it will be warm and steamy inside the cup.

If it is cold enough outside and the lid gets cool, I can make it rain off the inside of the lid, regardless of the outside air dewpoint.

MAKG1 said:
You can make your engine into a still if you overdo the heat and start to boil water out of the oil (there is always some).
Click to expand...

Yup. The higher the temperature, the faster things corrode, too.

The biggest thing I want are even temperatures. Not warm spots and cold spots.
 
Capt. Geoffrey Thorpe said:
What is the dew point INSIDE the crankcase (where it is filled with blow-by and not ambient air)?
Click to expand...

Again, that depends on a lot of variables.

Water is a significant byproduct of combustion. It frequently runs out the exhaust on my '64 chevy after a cold start when the combustion byproduct is warm and the exhaust system is still below the localized dewpoint (sound familiar?)

Engine oil will have water content.

How warm are you heating the oil?
How warm does the air above the oil get?
Are how humid does the crankcase get as that warm air gains moisture content?
Are there cold spots somewhere on that engine?
 
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Thanks for the ideas so far!

Heated hangar isn't a viable option - If there are any available, they're double the price of mine and would pay for the Reiff heater in 2 months.

I don't think the light bulb thing will work - The Ovation doesn't have cowl flaps, and there's no way a light bulb is going to fit past the exhaust to get into the lower part of the engine compartment. I don't think it'd even be particularly effective to put two bulbs in through the front of the cowling, as those openings are extended right back to the first cylinder, and I'm afraid I'd be heating the paint in there moreso than the engine itself, plus having them in the top means that the oil in the sump will get very little heat except by conduction, not likely enough to make a significant difference.

JHW said:
No need to conjure something up when the real thing is almost free. Go to your local TSC or farm&fleet store, buy a silicon pad heater for $15 and stick it on the bottom of your oil pan.
Click to expand...

In a certified airplane? :dunno: Even if it is legal, it'd probably ruin any impression a potential buyer had that it's a well-maintained airplane.

Also, if I'm gonna get a heater, I'm gonna do it right and get one that heats the whole engine to prevent any condensation issues. Hence, the $695 Reiff with the cylinder bands *and* sump heater rather than a sub-$200 sump heater.

Threefingeredjack said:
In the days before I had a heated hangar, I would drape a blanket over the cowl of the Comanche I then owned and put a small "milkhouse" heater on the floor just behind the nose gear facing aft. It was not touching nor near anything that would burn, and kept the area inside the blanket around 45-50 degrees when the outside temp was in the teens. The heater had a tip over and overheat switch. Never had any issue.
Click to expand...

That's the kind of solution I'm looking for - I have at least one old blanket and one old sleeping bag to donate to the cause, so I think I could make a three-sided "tent" under the nose of the airplane.

I know space heaters of the past had many safety issues, but is a modern space heater really that much of a risk? I have two that have thermostats and no exposed heating elements. As long as it's properly positioned away from the blankets and away from where they'd be if they fell, what's the risk?

Thanks!
 
Threefingeredjack said:
In the days before I had a heated hangar, I would drape a blanket over the cowl of the Comanche I then owned and put a small "milkhouse" heater on the floor just behind the nose gear facing aft. It was not touching nor near anything that would burn, and kept the area inside the blanket around 45-50 degrees when the outside temp was in the teens. The heater had a tip over and overheat switch. Never had any issue.
Click to expand...

Bingo.
 
N801BH said:
After that huge fire on the East coast that took out a row of hangars and alot of planes the FBO here, who owns the hangars banned portable heaters of any kind....
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So... What kind of heater caused the fire? :dunno:

It seems like at least a couple of people have had good results with this... ThreeFingeredJack and Geico, what kind of heaters did you use, and what was your assessment of the fire risk?
 
Having a good pre-heater in will increase the appeal of the plane. I'd just put one in. It makes someone believe the engine was pre-heated properly.
 
flyingcheesehead said:
So... What kind of heater caused the fire? :dunno:

It seems like at least a couple of people have had good results with this... ThreeFingeredJack and Geico, what kind of heaters did you use, and what was your assessment of the fire risk?
Click to expand...

I've used milk house heaters for 15 years, 24/7 during the winter. I have the thermostat set at 50f. Never had a problem.
 
denverpilot said:
All it would take is a small fuel leak... just sayin'.
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Nope, I've had fuel leaks, fuel spills, no issues. The amount of fuel is so small it evaporates. The fan inside the milk house heater moves the air away from he spill. It takes a spark and the right mixture for a fire.

Obviously, there needs to be some common sense, but 50 f is not hard to get and hold if you use your brain.
 
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Geico266 said:
Nope, I've had fuel leaks, fuel spills, no issues. The amount of fuel is so small it evaporates. The fan inside the milk house heater moves the air away from he spill. It takes a spark and the right mixture for a fire.
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Who says the leak must be small? I can drain out 64 gallons on the floor if the right component leaks and I'm not there for a few days.

That milk house heater wouldn't happen to have a bimetal strip thermostat with a contact set in it, would it???

If so, you've had the spark every time it cycles but just haven't had the right mixture yet.


I don't like sparky things down on the floor where the fumes might be.


177966_lg.jpg

bimetallic-thermostat-179.jpg
 
denverpilot said:
All it would take is a small fuel leak... just sayin'.
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Every once in a while I have a "Duhh!" moment. I rigged up an electrical heater with some dryer ducting that fed into the cowling (which was covered by a nice quilted comforter). I would turn it on in the morning (living in Indiana) and let it run all day while I was at work or doing errands and the engine would be nice and evenly warmed when I returned. No problem with getting over heated and burning the cowling since it was electric, though you didn't want to touch the funnel or tubing right next to the heater. This approach wouldn't do ANYTHING on the tarmac and didn't have any impact in an hour or two, but would really work well in a closed hanger, with an insulated cowling and 3-5 hours.

I set the heater back about 4-5 feet from the plane so it was sitting entirely by itself. I always thought, what can catch fire ... even if the heater itself would burn and smoke, there is nothing to catch.

Read this post and thought, oh Duhh, didn't think of a fuel leak ... now THAT would be a problem. I've never hard a fuel leak, so that failure mode just never dawned on me. Seems like a very low risk. That said, I don't fly night over the mountains single engine and the risk of that is predominantly just to me personally, not all the other poor slebs sharing my hanger.

A simple electrical heater really worked well for me, but there clearly are some low probability / high impact risks to consider.
 
We had a wing bladder tank fail in the hangar while no one was there... If there had been an ignition source sitting anywhere under/near the wing root...
 
A friend of mine lost his twin cessna to a fire from the guy next door heating his mooney's engine with shop lights. If you want a heater, get a heater. As for condensation, I know a little about that having formerly managed an engine cold test facility. All heaters are bad for your engine if you leave them on and worse if you let them cycle on-off.

ElPaso Pilot said:
Jeff,

I hate to start this thread down the wrong direction, but this needs the a few additional comments.

If only an oil pan heater is used, is is almost certain that it will not heat the entire engine above the dew point. This turns the cold portions into a terrarium as the water vapor released from the oil condenses in those cooler places.

Not necessarily a huge problem if one turns on the heater for a few hours and flies the plane, but turning on a stick-on oil heater and leaving it on out of convenience is not something I would do to my engine in a northern or damp climate. Particularly in a Lycoming 4 banger with the cam parked way up in the top of the terrarium tent.


My half baked compromise in the Mooney is a pair of 100 watt mechanics drop lights, one tucked up in each cowl flap. An insulated blanket on top of the cowl, cowl plugs in, and a hooded sleeping bag zipped over the prop (another big heat sink attached to the crankshaft).

Makes it look like a homeless bum, but I want the entire case, cam, and crankshaft warm and above the dew point.

I also make every attempt to fly it after I turn on the heat, which I can do remotely.
Click to expand...
 
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denverpilot said:
We had a wing bladder tank fail in the hangar while no one was there... If there had been an ignition source sitting anywhere under/near the wing root...
Click to expand...
If the hangar is closed up fairly tightly, a small fuel leak could produce a combustible mixture over a large area near the floor. If I were going to leave an electric space heater operating unattended near an airplane I'd put it up on something that kept it at least a few feet off the ground and run flex ducting to the engine bay.

Personally, I'd go for the Reiff system. It will come in handy if you ever have to park somewhere else overnight in the winter.
 
We bought small heaters, screwed round HVAC ducting to them and stick those in the intakes. Works fantastic.
 
Ted DuPuis said:
Having a good pre-heater in will increase the appeal of the plane. I'd just put one in. It makes someone believe the engine was pre-heated properly.
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Well, it'll certainly increase the appeal of the plane to those of us who live in areas where it's needed.

However, the plane has lived its entire life up until this point in mild climates where the temps never get low enough to require heat, which is why it's never had one installed.

I've been thinking all along I'd just install one if the plane hadn't sold by the time it got cold, but after coming *this close* to a deal with a guy who couldn't have cared less about an engine heater, I've been second-guessing that.
 
depends on the cowl,

I've wrapped my engine in a heated blanket, then wrapped those cheap silver space blankets around that, PITA, but worked great.
 
JHW said:
........All heaters are bad for your engine if you leave them on and worse if you let them cycle on-off.
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I respectfully disagree....


The engine in my plane stays heated to 140f on the oil side and 120 or so on the water side 24 /7.... Been doing that for 8 years and not a bit of problems.. Electricity is cheap out here and it costs less then one cent an hour to run both of my heaters.

For reference.......... back in an earlier life I built NASCAR motors and for the premier events like the Daytona 500 and a few others, all motors were run on the dyno and they stays plugged into the heaters until they went in the car, and even then a generator would be positioned next to the car to run the heaters till the start of the race.. 99% of the crew chiefs back then thought I was crazy.... Now EVERY car does that procedure. :yes:

YMMV.
 
flyingcheesehead said:
Well, it'll certainly increase the appeal of the plane to those of us who live in areas where it's needed.

However, the plane has lived its entire life up until this point in mild climates where the temps never get low enough to require heat, which is why it's never had one installed.

I've been thinking all along I'd just install one if the plane hadn't sold by the time it got cold, but after coming *this close* to a deal with a guy who couldn't have cared less about an engine heater, I've been second-guessing that.
Click to expand...

But clearly that guy didn't care enough to pull the trigger, either.
 
N801BH said:
I respectfully disagree....


The engine in my plane stays heated to 140f on the oil side and 120 or so on the water side 24 /7.... Been doing that for 8 years and not a bit of problems.. Electricity is cheap out here and it costs less then one cent an hour to run both of my heaters.

For reference.......... back in an earlier life I built NASCAR motors and for the premier events like the Daytona 500 and a few others, all motors were run on the dyno and they stays plugged into the heaters until they went in the car, and even then a generator would be positioned next to the car to run the heaters till the start of the race.. 99% of the crew chiefs back then thought I was crazy.... Now EVERY car does that procedure. :yes:

YMMV.
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That's nice. My lycoming's haven't been apart in 25 years. how long to nascar engines go ?
 
Hello All,

New to the community and thought I would share my heater setup. I thought about the Reiff or Tannis route but my mechanics hate them because so many people leave them on and the condensation issues become real. At their suggestion I set up a kerosene torpedo heater and ducting arrangement. I DO NOT leave this on if I am not there in the hanger. When I arrive the first thing I do is set it up and plug the heater in then go about my preflight inspection, call for fuel and so on. I in the 30 minutes or so it takes me to get all that done my engine is pretty toasty even at temps around 20 degrees. I use the gap between the heater and the ducting to control the temperature and have checked the temps with an infrared gun. At 20 degrees I can get the cylinders up to about 75 or 80 in 20 to 25 minutes. I always shut the unit down while sumping the tanks or taking on fuel. I would post pictures but I don't think I can to that yet.
 
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The issue with a torpedo heater (or the red dragon) is that you'll get the heat to support combustion in the cylinders, but the Tanis setups, left on longer, will actually get the cranks and such up to temperature where the clearances need to expand. It's really far from optimal.

When I've seen condensation on Tanis/Reiff heaters, it's been the people who let the things cycle on and off. There are other factors, too - which oil you use, humidity, how often you fly, etc.
 
"If it is cold enough outside and the lid gets cool, I can make it rain off the inside of the lid, regardless of the outside air dewpoint. "

I've had it rain in my hangar and even inside my airplane. Now I always leave a door open on the plane and the oil cap off the engine. I use a small ceramic heater that operates at 900w which sits on the muffler with a blanket over the cowel set to start 3 or 4 hours before etd. I don't see how a UL approved heater certified to use in a house is a fire hazard located in an area where there are exhaust pipes heated with 1500* exhaust. If you ran ductwork from a heater to the front of the cowl, you could keep it 18" above the floor just like a water heater in a garage.
 
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