Lots of subtopics within this thread.
We should break it out into a general engine corrosion discussion. Poor Whee just wants to preheat before flying.
Forced Air Engine Pre-heaters
Tue Nov 19, 2019 12:45 pm
Re: Forced Air Engine Pre-heaters
I'll post my $.02 Alaskan....
I think oil pan heater is a must, and temperature-controlled is really important to make sure you don't burn the oil on the bottom of your pan. Having warm engine oil makes the oil work much better (especially if you use straight weight), and you get oil pressure MUCH faster.
I think warming the engine itself is also important but less so to a point. If my engine was 30F and oil was 60F I wouldn't care, but as a rule, I don't hit the starter on anything that's below freezing, but I'm more worried about not getting oil quickly on top of that.
Because of this, I just use a hairdryer. On the lower setting it warms the engine up plenty enough in the amount of time the pan heater needs.
As MTV pointed out, all of this is pretty pointless if you don't have a cowl blanket that actually insulates the cowling well. Heat soaking something in cold temps requires insulation.
As for corrosion, you don't want water (condensation) inside of your engine. If you warm the air in the engine faster than the engine itself, you will have condensation, and if you have condensation you need to get the engine all the way to operating temp in order to evaporate it and push it out.
I think the best way to do this is to either have a very regulated setup (like a heated hangar), or only preheat when you are going to use the airplane and know that every time you preheat you need to get the engine to operating temp.
So for now, it's hairdryer, cowl blanket, and pan heater. I just built a cell based switchbox using a particle electron, but haven't used it much and as I'm not sure how much I trust the hairdryer. I'll probably switch to a floor-based heater with a duct into the cowl, then add some sort of RPM sensor to the heater.
I think oil pan heater is a must, and temperature-controlled is really important to make sure you don't burn the oil on the bottom of your pan. Having warm engine oil makes the oil work much better (especially if you use straight weight), and you get oil pressure MUCH faster.
I think warming the engine itself is also important but less so to a point. If my engine was 30F and oil was 60F I wouldn't care, but as a rule, I don't hit the starter on anything that's below freezing, but I'm more worried about not getting oil quickly on top of that.
Because of this, I just use a hairdryer. On the lower setting it warms the engine up plenty enough in the amount of time the pan heater needs.
As MTV pointed out, all of this is pretty pointless if you don't have a cowl blanket that actually insulates the cowling well. Heat soaking something in cold temps requires insulation.
As for corrosion, you don't want water (condensation) inside of your engine. If you warm the air in the engine faster than the engine itself, you will have condensation, and if you have condensation you need to get the engine all the way to operating temp in order to evaporate it and push it out.
I think the best way to do this is to either have a very regulated setup (like a heated hangar), or only preheat when you are going to use the airplane and know that every time you preheat you need to get the engine to operating temp.
So for now, it's hairdryer, cowl blanket, and pan heater. I just built a cell based switchbox using a particle electron, but haven't used it much and as I'm not sure how much I trust the hairdryer. I'll probably switch to a floor-based heater with a duct into the cowl, then add some sort of RPM sensor to the heater.
Tue Nov 19, 2019 1:29 pm
Re: Forced Air Engine Pre-heaters
Very interesting to see all the view points. Thanks for sharing guys.
I can't remember when I read this article from Mike Busch but it was a long time ago and made a lasting impression:
https://www.avweb.com/ownership/the-whys-and-hows-of-preheating/
Interestingly his point about the crank becoming an interference fit at very cold temps came to mind a few weeks back while watching 'Ice Pilots', enjoy the planes and ignore the drama. They were judging how cold the engines were based on how hard it was to turn the prop by hand, when the engine was "froze up" they couldn't move the prop at all.
Anyways, I've always thought heating then not flying is about the worst thing you can do so that is the main thing I'm trying to avoid while still having the plane ready when I want it. The lights seem to be working and I'm not so worried about them I can't sleep. Tonight it will be sorta cold and I might have an early morning departure so hopefully the lights keep working.
I can't remember when I read this article from Mike Busch but it was a long time ago and made a lasting impression:
https://www.avweb.com/ownership/the-whys-and-hows-of-preheating/
Interestingly his point about the crank becoming an interference fit at very cold temps came to mind a few weeks back while watching 'Ice Pilots', enjoy the planes and ignore the drama. They were judging how cold the engines were based on how hard it was to turn the prop by hand, when the engine was "froze up" they couldn't move the prop at all.
Anyways, I've always thought heating then not flying is about the worst thing you can do so that is the main thing I'm trying to avoid while still having the plane ready when I want it. The lights seem to be working and I'm not so worried about them I can't sleep. Tonight it will be sorta cold and I might have an early morning departure so hopefully the lights keep working.
Tue Nov 19, 2019 1:40 pm
Forced Air Engine Pre-heaters
Whee.....a friend Michael Schoder fly’s an immaculate PA12 with all the Alaska mods...he’s one of the guys who supports the Iditarod with his airplane. He uses a combination of Tannis and Reiff to heat his cold soaked airplane quickly in the middle of no-where using an 2kW inverter generator...personally my feeling is..an engine using either system with a good insulated cowl cover plugged in all the time is no more susceptible to corrosion than an aircraft stored in a warm hanger due to a consistent temperature.....on the plus side....the 
Tannis system has a permanent mount cabin heater... so even better for an airplane in a tin ice box....I haven’t mounted my cabin heater yet...
Sent from my iPad using Tapatalk Pro
Tannis system has a permanent mount cabin heater... so even better for an airplane in a tin ice box....I haven’t mounted my cabin heater yet...Sent from my iPad using Tapatalk Pro
Tue Nov 19, 2019 1:42 pm
Re: Forced Air Engine Pre-heaters
rw2 wrote: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.
Why isn't 35F enough? For example, Lycoming recommends pre-heating starting at 10F on most of their engines. They have a handful that they recommend 20F. I don't know of any that require pre-heating for temps any higher than that. So, wouldn't 35F be plenty?
It's just my personal preference. OIl pressure comes up too slow, the engine cranks slower, and the pistons/cylinder bore clearance could become an issue as the pistons heat quickly.
Continental says preheat is necessary if the engine has been exposed to air temps of 20F or colder for more than 2 hrs. CHTs and oil temps colder than 40F is when I start preheating. But, I plug in my pickup if the temps are 32F or below so I'm probably more conservative than most.
Tue Nov 19, 2019 1:59 pm
Re: Forced Air Engine Pre-heaters
Oh, also: I once witnessed my dad burn up a car with a lightbulb. Made quite an impression. I won't ever be using that solution.
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Thu Nov 21, 2019 4:27 am
Re: Forced Air Engine Pre-heaters
I'm just gonna leave this here. Been using them for years now. 150w infrared reptile heat lamps (one on both sides) and a 250w oil pan heater. Gets everything from 0 to 40F in 3 hours with a blanket on, 60F in 4 hours, maintains 80F plugged in overnight. I haven't tested it in severe cold yet. The bulbs are $28 at a pet store and advertised to last 20,000hrs.
*Edit* I get the temp data from my engine monitor. EGTs and CHTs are usually within a few degrees as the engine heats up. The bulbs are aimed at the collector on either side of the muffler.
*Edit* I get the temp data from my engine monitor. EGTs and CHTs are usually within a few degrees as the engine heats up. The bulbs are aimed at the collector on either side of the muffler.
-
- 150W infrared reptile lamps
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Thu Nov 21, 2019 8:57 am
Re: Forced Air Engine Pre-heaters
Reptile heaters, that's clever, but the zip ties on your engine mount are freaking me out. Especially the extension cord. That one is high risk to cut through and short some mains power right next to your engine mount.
Thu Nov 21, 2019 10:14 am
Re: Forced Air Engine Pre-heaters
akschu wrote:Reptile heaters, that's clever, but the zip ties on your engine mount are freaking me out. Especially the extension cord. That one is high risk to cut through and short some mains power right next to your engine mount.
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Thu Nov 21, 2019 12:35 pm
Re: Forced Air Engine Pre-heaters
akschu wrote:
Reptile heaters, that's clever, but the zip ties on your engine mount are freaking me out. Especially the extension cord. That one is high risk to cut through and short some mains power right next to your engine mount.
Hmm, I'll have a look at those the next time I've got the cowling off. The extension cord was installed as you see in the picture by an A&P and has been there for 15 years. My AIH drop lamp sockets don't have super heavy duty cords, but I also have them zip-tied in similar fashion. What's the best method?
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Thu Nov 21, 2019 1:02 pm
Re: Forced Air Engine Pre-heaters
born2flyak wrote:I'm just gonna leave this here. Been using them for years now. 150w infrared reptile heat lamps (one on both sides) and a 250w oil pan heater. Gets everything from 0 to 40F in 3 hours with a blanket on, 60F in 4 hours, maintains 80F plugged in overnight. I haven't tested it in severe cold yet. The bulbs are $28 at a pet store and advertised to last 20,000hrs.
*Edit* I get the temp data from my engine monitor. EGTs and CHTs are usually within a few degrees as the engine heats up. The bulbs are aimed at the collector on either side of the muffler.
Pretty cool solution. Thanks for sharing. Sounds like you’ve used down to 0F which is about as cold as I’d ever need.
Thu Nov 21, 2019 3:55 pm
Re: Forced Air Engine Pre-heaters
All of the following works well:
Slit some radiator/cooling hose and slip it over the mount and zip tie to that.
Wrap the engine mount with some UNI-WRAP Silicone Tape.
The double adel clamp
Velcro strap
Waxed kevlar lace
You could even use the doubled zip tie method to relieve the sharp part around the head. Like this:
The problem is that the zip tie in a high vibration environment could cut through that extension cord (or the mount itself for that matter) and then you could have an electrical fire under your cowl.
All that said, you might go 100 years and never have a problem, LOTS of people do, but when it comes to high voltage electrical wiring against critical high vibration stuff, I'd want a little more margin. Your call.
Slit some radiator/cooling hose and slip it over the mount and zip tie to that.
Wrap the engine mount with some UNI-WRAP Silicone Tape.
The double adel clamp
Velcro strap
Waxed kevlar lace
You could even use the doubled zip tie method to relieve the sharp part around the head. Like this:
- ziptie.jpg (92.48 KiB) Viewed 1438 times
The problem is that the zip tie in a high vibration environment could cut through that extension cord (or the mount itself for that matter) and then you could have an electrical fire under your cowl.
All that said, you might go 100 years and never have a problem, LOTS of people do, but when it comes to high voltage electrical wiring against critical high vibration stuff, I'd want a little more margin. Your call.
Thu Nov 21, 2019 10:45 pm
Re: Forced Air Engine Pre-heaters
akschu wrote:All of the following works well:
Slit some radiator/cooling hose and slip it over the mount and zip tie to that.
Wrap the engine mount with some UNI-WRAP Silicone Tape.
The double adel clamp
Velcro strap
Waxed kevlar lace
You could even use the doubled zip tie method to relieve the sharp part around the head. Like this:
The problem is that the zip tie in a high vibration environment could cut through that extension cord (or the mount itself for that matter) and then you could have an electrical fire under your cowl.
All that said, you might go 100 years and never have a problem, LOTS of people do, but when it comes to high voltage electrical wiring against critical high vibration stuff, I'd want a little more margin. Your call.
Good info. Thanks! I'll bring it up to code when it's in the hangar in a few weeks.
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Fri Nov 22, 2019 7:24 am
Re: Forced Air Engine Pre-heaters
Well, goes to show ya.....Rube Goldberg is alive and well. Spend a gazillion $$ on an airplane, and really work to find cheep ass heating solutions.....
MTV
MTV
Fri Nov 22, 2019 11:30 am
Re: Forced Air Engine Pre-heaters
Whee, I know this isn't what you want to hear, but after installing the Reiff Turbo XP system, all I can say is Wow! In addition to the high wattage, conducting heat to the engine seems to be a lot more efficient than convecting heat to it.
If you have the ability to turn it on via wi-fi or cellular, I think you could pretty easily forget about keeping the engine warm all winter and still be able to fly more or less on demand, if not on impulse.
And the savings in electricity might go a fair ways towards the purchase...
If you have the ability to turn it on via wi-fi or cellular, I think you could pretty easily forget about keeping the engine warm all winter and still be able to fly more or less on demand, if not on impulse.
And the savings in electricity might go a fair ways towards the purchase...
Fri Nov 22, 2019 1:25 pm
Re: Forced Air Engine Pre-heaters
Hammer wrote:Whee, I know this isn't what you want to hear, but after installing the Reiff Turbo XP system, all I can say is Wow! In addition to the high wattage, conducting heat to the engine seems to be a lot more efficient than convecting heat to it.
If you have the ability to turn it on via wi-fi or cellular, I think you could pretty easily forget about keeping the engine warm all winter and still be able to fly more or less on demand, if not on impulse.
And the savings in electricity might go a fair ways towards the purchase...
Cost of electricity is no factor. We pay a annual flat rate.
However, I think your right. A Turbo Reiff and a cell switch is probably the right answer. That’s not going to happen this year. We sewed up an engine blanket and with two 100W bulbs on overnight the CHTs and oil are in the 60s the next morning. We’ll get through the winter with what we’ve got.
Sat Nov 23, 2019 8:44 am
Re: Forced Air Engine Pre-heaters
whee wrote:….. We sewed up an engine blanket and with two 100W bulbs on overnight the CHTs and oil are in the 60s the next morning. We’ll get through the winter with what we’ve got.
It doesn't get much better than that.
Why again do you wanna change?
Sounds perfect for hangar use.
FWIW there's a very similar discussion right now on SC.org site.
Pretty much the same comments & opinions.
https://www.supercub.org/forum/showthre ... t=pre+heat
Last edited by hotrod180 on Sun Nov 24, 2019 9:08 am, edited 1 time in total.
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Sat Nov 23, 2019 5:47 pm
Re: Forced Air Engine Pre-heaters
If you have a daughter with horses borrow one of these blankets from her, she will never think to look in your hanger for it and remember to remove it before you open hanger door if you want to keep it. This horse blanket along with that milk house heater would get engine toasty warm in one hour on high in minus 20 weather.
Sat Nov 23, 2019 6:54 pm
Re: Forced Air Engine Pre-heaters
There are different ways to preheat.
Then there is the right way.
1) buy a good engine cover. Make sure it’s long enough to cover all your cowling openings. Including underneath. Nothing steals your heat like the wind.
2) install a Reiff or a Tanis. Ford/Chevy, Miller/Budweiser; everyone has there preference.
3) install a bootcowl plug-in with a dummy light. This keeps the extension cords away from the cover and let’s you know you have power to the plane.
4) install a pig tail cord into the cabin. Plug your thermostat controlled heater into it and care for your interior instruments, etc. I set mine on a cookie tray because it makes me feel better.
This is a recipe for success. We are hearting different types of metals, oil, air, etc. All of these things accept heat at different rates. Low and slow heat will warm to the core. The goal isn’t to cook an egg on your artificially hot cylinder surface but get heat deep down into the engine. Heat overnight or leave plugged in for longer and then fly your plane and achieve appropriate oil temperatures.
I have the unfortunate experience (15 years) of flying winter/spring in northwest Alaska without a hangar. Take care of your engine, because you want it to take care of you.
Then there is the right way.
1) buy a good engine cover. Make sure it’s long enough to cover all your cowling openings. Including underneath. Nothing steals your heat like the wind.
2) install a Reiff or a Tanis. Ford/Chevy, Miller/Budweiser; everyone has there preference.
3) install a bootcowl plug-in with a dummy light. This keeps the extension cords away from the cover and let’s you know you have power to the plane.
4) install a pig tail cord into the cabin. Plug your thermostat controlled heater into it and care for your interior instruments, etc. I set mine on a cookie tray because it makes me feel better.
This is a recipe for success. We are hearting different types of metals, oil, air, etc. All of these things accept heat at different rates. Low and slow heat will warm to the core. The goal isn’t to cook an egg on your artificially hot cylinder surface but get heat deep down into the engine. Heat overnight or leave plugged in for longer and then fly your plane and achieve appropriate oil temperatures.
I have the unfortunate experience (15 years) of flying winter/spring in northwest Alaska without a hangar. Take care of your engine, because you want it to take care of you.
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Sat Nov 23, 2019 7:27 pm
Re: Forced Air Engine Pre-heaters
...and I guess I'll add that although I really enjoy reading this site I rarely post anything. Mostly because in most circumstances there can be a lot of different ways to do things, and still be ok. But I have seen ALOT of dumb ass preheat scenarios that leave me shaking my head. So I though I'd add my 2 cents on this one.
Like I said, take care of your engine, because you want it to take care of you.
Like I said, take care of your engine, because you want it to take care of you.
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