Pre-heating time has arrived so I'm looking at options. Tanis and Reiff have been pretty toughly covered so no need to discuss that. What I'm wondering about is forced air, basically spaces heaters, that are designed to be placed directly in the engine compartment. I'm keen on this setup because there is no ducting and it heats the entire engine compartment. So as far as the battery and engine know it is still warm out. The condensation concern has also gone away since the entire engine compartment is warm. I never know when I'm going to fly so leaving it pulled in all the time would be great.

Here's a few options:

https://www.aircraftheaters.com/specifications

The Twin Hornet 22 looks pretty good but I wonder if it puts out enough heat. 200W isn't very much. They used to make a Quad Hornet which is what a local guy has and it looks great but the price seems a bit high.

Their Hornet 45 is attractive and rated to be in an engine compartment but the company told me that's not what it was meant for so it wouldn't work.

https://aerothermheaters.com/store

This one doesn't fit in the cowl, I don't like the ducting and it's silly expensive.

Those were the only airplane specific ones I could find but here are a few other options:

https://www.amazon.com/Zerostart-2600900-Interior-Electric-Portable/dp/B000NM73ZA

This one I found via sc.org. Seems like it's pretty popular in AK and Canada. It's not rated as ignition/explosion proof which makes me nervous but seems like plenty of guys are using it with success. Price is nice but maybe it is too cheap. I'm not sure I'd be any more comfortable with it than I would be with my current setup.

https://www.boatbilgeheaters.com/
This one is a boat engine room heater rated to be in an engine compartment. Obviously it is the same outfit as aircraftheaters.com but at boat prices rather than airplane prices. The Twin Hornet 45 would fit nicely in my cowl.

https://theboatsafe.com/products/boatsafe-minimax-600w-engine-heater
Another boat heater. Seems like it would work well, has great reviews and the company seems pretty cool. Looks like a few marine stores offer it for ~$300.

The problem with the boat heaters is they are preset to turn on at 40F and turn off at 55F. I suppose that is good enough since 40F is where I start preheating.

For being left on continuously I don’t see any advantage over light bulb(s). A thermal switch can be had for about $40 if you want more precise control than you get from adjusting bulb wattage.

Hammer wrote:For being left on continuously I don’t see any advantage over light bulb(s). A thermal switch can be had for about $40 if you want more precise control than you get from adjusting bulb wattage.

My hangar is cold and my blanket/nrs strap cover likely isn’t the best. A 150W bulb only got the CHTs to 35deg when left on over night and burned out after 3 uses. Maybe I should try those long lasting led blubs? [emoji16]

What about a heat lamp? I tried that last year but couldn’t sleep...

-0-

whee wrote:

Hammer wrote:For being left on continuously I don’t see any advantage over light bulb(s). A thermal switch can be had for about $40 if you want more precise control than you get from adjusting bulb wattage.

My hangar is cold and my blanket/nrs strap cover likely isn’t the best. A 150W bulb only got the CHTs to 35deg when left on over night and burned out after 3 uses. Maybe I should try those long lasting led blubs? [emoji16]

What about a heat lamp? I tried that last year but couldn’t sleep...

I'm surprised the bulb burned out so quickly...was it touching something? Personally I'd try two (or even three) 150W bulbs mounted in cans so the bulb can't touch anything and see where that got me. Not sure about a heat lamp...never really played around with them before. Might also go to the DI and get some more quilts for the cowling.

It just seems like there's less to go wrong with light bulbs than a forced-air system, especially if left on all the time.

Tanis makes a cabin heater, looks like you could stick it under the cowl.
DENNY

I'd go with dogpilot's recommendation, for continuous use. Actually, I'd recommend against continuous use, but that's another story.

I would NOT recommend any fan forced air heater for continuous use, nor would I recommend remotely starting one, for that matter. All it takes is for the fan to not start (cold can do that) and the overheat sensor to fail and you just burned your pride and joy down....and the hangar.

So, I'd recommend buying an Ez Heat thermostatically controlled pad, install it, and also buy one of those Zerostart fan forced air heaters.

Install the EzHeat pad, and plug it in. Now, when you get ready to go flying, plug in the Zerostart heater, put it in the engine compartment as well, to "top off" the heat. You'll take a half hour or so to get going, and that extra heat will help if it's colder than, say 0 F.

To make all this work in ANY case, order a custom fitted insulated engine cover. Two reasons for that: First, it'll hold the heat in waaaaay better than any blanket/sleeping bag, etc, that isn't fitted carefully to close up the engine compartment. Second, when you do go flying in the winter, carry that engine cover along and when you stop somewhere for lunch or skiing, etc, put the fitted engine cover on and when you come back in an hour or two, that engine will still be toasty.

The Zero Start heaters put out a lot of heat, and they are nearly bomb proof. Used to be called "Little Buddy" heaters. Same unit, different name. The only thing I'd be concerned with is keep them away from fuel lines/carburetor, etc, and BE THERE when it starts. In very cold temps, the fan may really struggle to get going. If the fan fails to start, there is a disconnect if the heater over heats, so should be safe. BUt, that's a lot of assumptions that I'd rather not make around my airplanes.

Finally, to illustrate how tough those little fan forced heaters are, I once plugged one into 240 Volt outlet......an A&P who thought he was an electrician wired a 110 V outlet onto 240 power.....and I plugged that little heater into it. I did this for a friend, at his request. A few days later, I ran into him, and he laughingly accused me of trying to burn his 170 down. He said that little heater had been running on 240 for two hours and it sounded like a J-58 jet engine. But, it still worked the next day..... amazing.

I carry a Little Buddy/Zerostart heater with me on the road in winter. If I get stuck somewhere I put on the engine cover, insert the heater, and plug it in a few hours prior to launch. When I first plug it in, I simply listen closely so that I hear the fan start. If that works, I know the heater is probably safe.

MTV

https://amzn.to/35eIONn

Cheap and easy. with a blanket it works fine.

Or these work with a piece of scat tubing attached. nice little stand to aim upward
https://www.harborfreight.com/1600-watt-heavy-duty-dual-temperature-heat-gun-10001100-69342.html

I do like the idea of the aerotherm heaters. I think being outside of the cowling adds a safety aspect rather then being inside of them. They also move a lot of air, and airflow helps. You could probably open your cabin heat and itd warm the cabin up right away as well. If I had multiple planes I'd definitely buy one rather then installing a tanis/reiff in every plane. I may still buy one as I often preheat customers planes for run ups before work. I've had good luck with ez heat pads, but that's not part of this topic. Light bulbs sketch me out a bit. Seen a couple to many trouble lights explode and I personally wouldn't want to stick one in my cowling unattended. The little buddy heaters work good as well. Just takes time, but with the cowl covered it will do the job.

whee wrote:.....My hangar is cold and my blanket/nrs strap cover likely isn’t the best. A 150W bulb only got the CHTs to 35deg when left on over night and burned out after 3 uses. Maybe I should try those long lasting led blubs? [emoji16] What about a heat lamp? I tried that last year but couldn’t sleep...

My last two planes, from about november to march or so,
I used a heat lamp bulb screwed into a trouble light hung under the oil pan with a blanket thrown over the cowl.
Engine was always warm to the touch. The trick is to use the right bulb--
most heat bulbs are 250W but they do make a 125W which is not so hot as to make me (too) nervous.

I'd still be doing the same thing all winter,
but the heat bulb doesn't fit up through the cowl flaps on my current airplane.
Exhaust etc is in the way also.

I've been using this 300 Watt heat lamp for a few years. It fits in the lower left area of my 180 because of the big cowl doors. I point it sideways toward the oil pan and with the ancient Kennon insulated engine cover, it gets things pretty warm. I don't fly if it's real cold and so far have been chicken to plug it in the night before but do leave it unattended for several hours at a time.

whee wrote:….
https://www.aircraftheaters.com/specifications
The Twin Hornet 22 looks pretty good but I wonder if it puts out enough heat. 200W isn't very much. They used to make a Quad Hornet which is what a local guy has and it looks great but the price seems a bit high.
Their Hornet 45 is attractive and rated to be in an engine compartment but the company told me that's not what it was meant for so it wouldn't work. …..

On a friend's recommendation, I bought a Quad Hornet a few years ago but wasn't satisfued with it.
Engine was never warm to the touch.
It might be good at keeping the engine at 30 degrees when it's 0 out,
but I was looking for more like keeping it at 50 when it's 20 to 30 out.

$15 blow dryer and scat tube. Has overheating and gfci protection built in. Regardless of what you use, get an engine blanket.

But really, a few hundred for Tanis/Reiff to really get your engine heat soaked safely is hard to beat.

I have the Twin Hornet 22. I am in a hangar and I have a very good and tight cowling blanket. Also, my engine and engine compartment are small (Rotax). With all that said, I am happy with my choice. I see oil and water temps of ~65* even on a cold morning (with the thermostat, that's about as hot as you will ever get). Like you, I didn't like condensation issues of a heating element on the engine block itself. Also, the element does not heat at a high temp; in fact with the unit on, you can put it up against your face with no harm or even discomfort. Also, the idea being that the unit is safe if their aren't any temps high enough to ignite anything. Plus all connections are potted so no arcs possible. The heat is moved around by the fan in the unit. IMO, this is a "leave it on" unit, not a "plug it in two hours before you plan to fly" unit. I like it and it serves me well but I would agree with those that have issues IF you are outdoors in wind or your cowl blanket is insufficient. If that is the case, I'd say it is near a waste of money. In a hangar, good blanket, on all night, it will work well.

Seems most aren’t keen on forced air heaters. IDK how they can be safe for $500,000 boats but not an airplanes. I still might give one a try.

Those Kats head pads don’t have any thermal protection and I’m chicken. But I did find some for like $80 that are thermally protected. Maybe a good option but not a solution I can leave on all the time.

I planned to install a Reiff but the price is now almost $700. Maybe worth it but not this year.

Last night I stuck a second 100w light in the cowl and wrapped it up better with a second blanket. Glad it work because I went for an unexpected flight this morning. The engine was 60deg when I got to the hangar but it wasn’t cold last night.

hotrod180 wrote:On a friend's recommendation, I bought a Quad Hornet a few years ago but wasn't satisfued with it.
Engine was never warm to the touch.
It might be good at keeping the engine at 30 degrees when it's 0 out,
but I was looking for more like keeping it at 50 when it's 20 to 30 out.

If your interested in selling the Quad send me a message. My friend that has one locally really likes his so I kinda want to try one.

Greg,

Too many moving parts in fan forced heaters, at least for 24/7 use.

Buy an EZ Heat and an engine cover. The EZ Heat has thermal protection and a thermostat. I think it’ll do everything you need. It’s relatively cheap and easy to install.

MTV

I sent a 0-470 to Western Skyways for an overhaul about 8 years ago and they said the engine was rusty from leaving my Tanis plugged in all winter. They even sent me back a bag of rusty lifters for an example. It was really kind of hard to believe since the plane flew pretty often even through the winter. They said that kind of rust in an engine was common for guys like me who left their heaters on all the time. There was quite a bit of rust, and to this day its still a bit hard to believe.
I've since switched to a good engine blanket and a 100 watt light bulb incased in one of those old fashioned steel caged drop lights. I reach up through the cowl flap and hang it on the side of the engine. Outside my hangar it can be in the teens and my engine compartment will still be above 40F.

Ron

So there seems to be a array of options; forces air, strap heater, dangling lightbulb and as many processes as well. If we accept that it's not us and our creature comfort but about what's best for the engine I'm left with this question. It's a question of process and how to best go about applying heat; continual, day of, clearly a common requirement is a well fitted engine cover. Does anyone heat the battery as well to maintain its efficiency. Winter has arrived with a vengeance in my corner of the globe so preheating season has arrived and I don't have my skis on yet, nuts.

Mapleflt wrote:So there seems to be a array of options; forces air, strap heater, dangling lightbulb and as many processes as well. If we accept that it's not us and our creature comfort but about what's best for the engine I'm left with this question. It's a question of process and how to best go about applying heat; continual, day of, clearly a common requirement is a well fitted engine cover. Does anyone heat the battery as well to maintain its efficiency. Winter has arrived with a vengeance in my corner of the globe so preheating season has arrived and I don't have my skis on yet, nuts.

As usual in these discussions, the simple answer is: It depends.

It depends on how cold the ambient temps get. It depends on whether the plane is parked inside an unsheathed hangar or out in the open air. It depends on how early you need to launch in the AM. It depends on whether you have access to electricity.
It depends whether you have phone or cell service to your parking spot.. It depends how big your engine is. It depends what the ambient relative humidity is. And probably ten other “depends” I haven’t noted.

The one constant I recommend is to get a GOOD insulated engine cover.

Maybe it’s time for me to write something up and send to Zane. Thirty years plus starting airplanes in very cold temps offers perspective, and I’ve tried just about everything.

Stand by.

MTV

Maybe it’s time for me to write something up and send to Zane. Thirty years plus starting airplanes in very cold temps offers perspective, and I’ve tried just about everything.

Stand by.

MTV[/quote]

Mike, please do! Your vast experience with this type of thing would be greatly appreciated!