engine warming

G

guzziduck

New member
How do you guys feel about preheating your engine? Last year I kept the engine warm all he time in the hanger by using a small electric space heater under the cowl and an old quilt drapped over the top, that way the plane was ready to go whenever I got the chance to fly, tried to get at it about once a week. Been hearing from some that this is not a good idea as it can cause condensation inside the engine and that warming should only be done about half a day before flight. That makes for an extra trip to the airport and with the weather this year I'm never sure when I can get out. The only way I can see that condensation could occur is if cold air comes on the intake or exhaust and contacts the warmer metal of the engine, would it help if these were plugged during warming or would it be advisable to make a shroud that cover the entire engine compartment, intake and tailpipes and all and have the heat source low enough that the warm air gets into those areas as well ? Getting above zero this week hope to do some flying. Thanks, Richard
 
Anyone with cold windows in their house or a nice cold one on the table knows that humidity in the air will preferentially condense on the coldest surface as visible water. With the addition of heat in the hangar there will be an equilibrium established with moisture evaporating from engine surfaces and on to other cold surfaces in the hangar environment. If the engine is the warmest area of the hangar than there will be a net decrease in water content in the engine area and a net increase in water content in other areas of the hangar. Your engine will be helped by being the warmest spot in the vicinity. Even though the air in the hangar and engine will all have water content, the relative humidity will be lowest in the warmer areas and low relative humidity means lower rust, etc. If air that is foggy at 15 degrees centigrade (100% humidity)is heated 10 degrees C to 25 it's humidity will fall to 50%
 
While we are on the subject, what is the opinion of putting an electric heat tape on the bottom of the oil pan? I have one on my ATV but it gets quite hot. It would keep the airplane oil warm/hot but the upper part of the engine probably wouldn't benefit much from it. :?:
Gary
 
I have an electric heat pad on the oil pan of my Franklin and the entire engine keeps warm. Even the cylinders stay warm to the touch.

Kevin
 
Places like chief aircraft and Aircraft Spruce, etc, all sell approved engine heaters. Usually a pad that RTV's to the bottom of the engine, but also heated rings for the base of the cylinder and even in the past I have seen heated dipsticks. There is always the ducted engine heaters like the red dragon for instant heat, but that gives a warm metal engine holding cold oil, so overnight heating methods are best. A droplight (plastic so no metal parts get overheated and damaged) thrown into the engine compartment bottom combine with an insulating cover that closes the cowl (an old blanket) is also reasonable depending on the temperatures involved. I have heard that hooking a hose up to a car exhause will make a poor mans red dragon, but I vote against that solution as the engine will be bathed in all kinds of water with various acids and chemicals from the burnt auto gas.
 
Some years ago I had a PA22 and kept a 100 watt light bulb under the oil pan. It worked fine except the bulb kept burning out. I say it worked fine because the plane would start but I never knew if the engine was warm or just the oil. The company that builds Tannis Engine Heaters is only fifteen miles from here but they are quite expensive. We do have it on our PA28 and it works great, but I think I'll add a heat tape or a heating pad to my Franklin before we "hook it up".
Gary
 
I heard stories that warm air holds more moisture than cold air that moisture mixes with the contaminants in oil causing corrosion. So I read the ops manual on the Tannis web site. The manual recommends 4-5 hours prior to flight that the heater be turned on. The manual says the heater can be left on up to a week if the airplane is flown.
 
Six or eight hours...or all winter on our Cherokee. :D We keep it heated all winter. If I want to go somewhere or just for a ride, I don't want to have to make two trips to the airport and wait six or eight hours.
Gary
 
Warm air holds more moisture than cold air. that is why heating the engine is good. The warm air in the crankcase will hold the moisture in the air rather than let it precipitate out on metal surfaces where it will cause more harm. A bulb will last about 1500 hours so 24/7 it will last about 60 days. Another thought would be to buy a heating pad and throw it in the engine compartment. Less chance of fire (a bulb gets quite hot in a small area-if a drop of flammable liquid were to drop on the bulb, and crack it, then that fluid would be subjected to a white hot filament and POOF! I haven't tried a heating pad, so someone else will have to report how well it works. Unless one has multiple places with electricity available, it doesn't make economic sense to permanantly attach a heater to the engine (though it might be more efficient)
 
E-Z Heat makes an affordable unit for the Franklin that is easy to install and can be plugged in all winter without carbonizing the oil, I have one on my Cruiseair and soon to be on my Cruisemaster.....Greg
 
Never had to deal with the cold much in N Calif but the previous owner of my Cruisemaster is from alaska and his prefered method was the light bulb and a quality cowling blanket. When he was traveling he could take it all with him but when in extreme conditions like below <0 and in the bush he would drain the oil when hot, put in on the fire with breakfast and pour it in hot write before engine start. Glad I don't have to do all that just to go Flying. Brian
 
Greg, I checked out E-Z heat which is out of Chetek, WI. A small town, but my sister lives there and I get over there several times a year. The heater is only $169.00.
Gary
 
I have a heat magnet on my oil pan, This is really a nice gizmo bought from NAPA for about 35 buck. I plug it the night before as the airport is on my way home from work so I stop by and plug it.
It keeps the oil warm, It really works well. Then the morning after, I get to the airport about an hour before departure and plug my little ceramic cube heater that is under the cowling, behind the engine on the left side, blowing at the accessory panel and under the cylinders.It,s important to warm up the oil cooler too as the oil could be like gelly in there and a hose could blow off or something. Not good.
After an hour and while I did my pre flight, and remove the nice tarp I have to keep it warm, I unplug everything, remove them (the cube and the magnet) and engine is nice and warm. 3 shots of prime, 4 to 6 blades by hand, just touching the starter button and the thing is puring like a big kitty. Never fail. I have my hours of winter flying here in Quebec. But I never go flying this bird below -7 or -8 centigrade (18 to 20 F). There is no winter kit on this thing and oil temp stay too low if colder than that. And with the heater we have in there, it's also my arss that gets too cold.
I have the mecanical gear with the crank...Are these gears stiff to raise in the cold or what!!! :shock:

Alain.
 
Many planes have baffles for the oil cooler that cover up about half the cooler, so oil exiting the cooler is not too cool and there is less danger of the oil becoming so viscous that there is no oil cooling and the engine overheats.
 
I had stated earlier that we keep our Cherokee plugged in all winter and we have a small ceranic heater that we stick in the cockpit a little while before starting the enging to warm the instruments as well as where I place my butt. We recently bought heated floor mats (Tannis) that will keep the cockpit warm all of the time. In the summer we just unplug them and put them up until cold weather comes back. I do plan to put a EZ Heat pad on my 1413 before the engine goes in.
Gary
 
Yes Peter, Seen all these winter kits for different birds, it's just a bit ackward to go and install one on the franklin the way it is set up in the Cruisair.
 
Alain,
What is the difficult part of putting a heater on a Franklin? I thought I could simply put the EZ heater on the oil pan and be done with it. I realize I may have to remove the oil cooler to accomplish this but what other problems may I face? The engine is hanging on the chain hoist so I thought it would be easy.
Gary
 
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