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How to preheat my engine when away from home?

Guy Prevost

Guy Prevost

Well Known Member
Since I only have about 20 hours on the Barrett engine rebuild I'm extra sensitive about preheating right now. It's no problem at home, but traveling seems to be a different story.

A few weeks ago, we flew into Telluride. The FBO happily preheated me for a fee. As I was preflighting I noticed outlets on the ramp--it turns out I could have plugged in there for free--it didn't even occur to me to ask.

This weekend I'm headed to Denver Centennial (KAPA). The lady on the phone at Jet Center didn't think they could preheat a piston airplane. That seems surprising to me, but it's not supposed to be that cold on Sunday afternoon so no big deal.

What do you guys do?
 
Guy Prevost said:
Since I only have about 20 hours on the Barrett engine rebuild I'm extra sensitive about preheating right now. It's no problem at home, but traveling seems to be a different story.

A few weeks ago, we flew into Telluride. The FBO happily preheated me for a fee. As I was preflighting I noticed outlets on the ramp--it turns out I could have plugged in there for free--it didn't even occur to me to ask.

This weekend I'm headed to Denver Centennial (KAPA). The lady on the phone at Jet Center didn't think they could preheat a piston airplane. That seems surprising to me, but it's not supposed to be that cold on Sunday afternoon so no big deal.

What do you guys do?
Click to expand...

I always carry an extension cord with me. I have a Reiff system installed. You can usually find a plug if you look hard enough.
 
How remote ?

If you are really out there( On a frozen lake) build a wood fire a good safe distance from your RV. After you have an ember bed with no flames, pull the RV ahead and let the hot air rise through the cowl exit. A large blanket helps.

Not recommended at an FBO

Or if you want to spend some money, there are large foldable solar panel units like a large blanket(s) you can lay out on your wings, with enough watts to power a ceramic 12V "HORNET" heater. Aircraft Spruce used to sell a wide array of Hornet Heaters in various voltage and outputs. They have a safe high temp limit.
 
Wait....is this the same theory that you can throw a lit cigarette into a bowl of gasoline and it will not ignite?.......most of the time? :eek:
 
I have a 120V oil pan heater on my plane and would carry a 100' extension cord with me if I were flying somewhere cold. I've seen people use an electric hair dryer, too.
 
I just installed a sump heater for cold mornings in south Georgia. Most days, it is not needed but when I travel to visit family in PA, it will be plugged in a couple hours ahead of my crank-up time.

< $32, at the moment.

When at home base, it will be turned on remotely via this power strip that can be controlled with a phone app over the internet. Each outlet is individually controllable.
 
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rleffler said:
I always carry an extension cord with me. I have a Reiff system installed. You can usually find a plug if you look hard enough.
Click to expand...

+1. 100' extension cord worked at FBOs in Lawrence, KS and Angel Fire, NM. My only cold weather experience to date.
 
Raymo said:
I just installed a sump heater for cold mornings in south Georgia.
Click to expand...
Those things are great but, be aware that different sumps require different heaters. Mine has a cutout so as to miss the sump drain. I glued it on with J-B Weld.

4wcG7I.jpg
 
Raymo said:
I just installed a sump heater for cold mornings in south Georgia. Most days, it is not needed but when I travel to visit family in PA, it will be plugged in a couple hours ahead of my crank-up time.

< $32, at the moment.

When at home base, it will be turned on remotely via this power strip that can be controlled with a phone app over the internet. Each outlet is individually controllable.
Click to expand...

I have a Reiff sump heater and a remote device at home. Power on the road is the issue. I've even considered one of the goal zero power packs, but don't want to spend $1000 on it.
 
There are ~$120 2 stroke generators that would be sufficient to run a Reiff system for a while on a tank of gas. You could carry one of those and only put enough fuel in the tank to run it for the length of time you want.
 
Guy Prevost said:
I have a Reiff sump heater and a remote device at home. Power on the road is the issue. I've even considered one of the goal zero power packs, but don't want to spend $1000 on it.
Click to expand...

That really is the issue:

If I fly to Syracuse to visit my mother and stay for 2-3 days, I either have to go out to the airport a few hours before flying home to plug in the Reiff system...or leave it plugged in for a few days.
 
There are lots of options available. While the ember bed idea sounds crazy, it's not really all that crazy - I've used it lots of times on cars and tractors - just put the embers in a steel shovel and slide the shovel under the oil pan.

When it comes to airplanes I'm not ready to take that level of risk. A hangar neighbor uses a pair of piezo-igniting propane torches and a small battery-powered 12V fan. The fan sits at the bottom of a galvanized steel "chimney" made from home heating duct. The torches are cut into the sides of that chimney. A flexible aluminum duct comes off the top of the chimney and can be directed under the engine cowl, thus eliminating the possibility of ignition of aircraft combustibles through direct contact with the torch flame. He uses a small rechargeable battery pack to power the little computer fan that circulates the heat into the engine bay. Works a charm for truly off-airport pre-heating. (Although one does have to be comfortable with carrying propane cylinders in the airplane.)

As for me, it's a Reiff preheat system. If I really need to go off-airport I'll be carting along a tiny 2-stroke generator to make the necessary electricity. Something tells me my wife won't be wanting to go off-airport camping in temperatures where that kind of serious pre-heating will be required... ;-)
 
Extension cord and hair dryers. Use 3-hair dryers for preheat at my tie-down. Total cost was $33 at Walmart. Two in the inlet over the cylinders and one down below aimed at the oil pan.

If not possible with electric, I use a small dual fuel, singe burner camp stove.

To direct heat into cowling at the exhaust opening, use a 6" x4" HVAC duct reducer into a 4" dryer hose. A short piece of 6" duct around the stove clears the height of the stove and then the reducer necks down to the 4" hose. The hose is aluminum and expandable. Small light weight and portable. Holes drilled in bottom section for air flow.
Stove_Pre_heat1.jpg


Stove_Pre_Heat2.jpg


A small primus fuel bottle and I have enough fuel for 3-hour warm up.

I would use caution if using propane, have had the moisture, from the burned propane, freeze the throttle cable in the past. (0 deg F and below).

Best regards,
Mike Bauer
 
there are a lot of stick on pad dimensions and wattage. on my jab 3300 i have 300watts stuck on the oil pan and 50 watts on the top of the block. 3 hrs is always enough in the temp i will fly in [15 f. ] .oil is always around 100 deg and heads are 70 deg. if you were to leave it on constantly temps will reach a max when engine gives off heat as fast as it absorbed. i think mine is around 70 deg above ambient. the only reason i have 4 stick ons is because i was experimenting with my preheating.i plug the intake vents and drape an insulated pad over the cowl.safety i think is much greater with these pads compared to a milkhouse heater that gets red hot and has a motor that can jam/fail etc.
i have used these stick ons in many auto applications and never had one fail. my last car still had a working pad on it with 300,000 miles. and that was on a curved oil pan.
350 watts is peanuts for an extension cord and a light one [16 ga] is fine for quite a distance.
 
I had a Tanis heater on my 7A. I think they are the best way to go. Heats pan and cylinder heads.

Roberta
 
Wolverine Sump heater pad - the Orange ones, about £80 on UK ebay. (But DONT trim them or it will destroy it .... ask me how I know !)

Then I have a "Cellphone" Mains socket adapter, you send an SMS to the cell number and it switches on for an hour. At 40f ambient I usually see about 70f oil temp at startup after it's been on for an hour.

There's also Wifi sockets which are even cheaper (£20) but of course need a wifi connection. I've not mentioned what types as I'm in the UK and our outlets are different here.
 
snopercod said:
I don't see how that could possibly hurt anything. That's what I would do.
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Yep, I had one of those Amazon special stick on pads and it was great. I'd plug it in the night before with a blanket over the cowl and by morning the engine was warm all the way to the head fins. Obviously, 300 watts can't overwhelm the cooling capacity of the engine, so leaving it on indefinately is not going to increase temps beyond about 80 degrees.
 
Plummit said:
It's not a theory, it's a fact. :D

-Marc
Click to expand...

Well.......if....the lower explosive limit LEL of 1.2 and the upper explosive limit UEL of 7.1 of gasoline ever present themselves with the other two elements to support BOOM! stuff we have a problem. Fuel tank vent....air containing oxygen......and a heat source......:eek:
 
Canadian_JOY said:
There are lots of options available. While the ember bed idea sounds crazy, it's not really all that crazy - I've used it lots of times on cars and tractors - just put the embers in a steel shovel and slide the shovel under the oil pan.
Click to expand...

Done the same thing for trucks and equipment. Normally used a small bag of charcoal. Lite the bag on fire and as soon as the paper burns off, slide the charcoal under the engine. That or the old pull the air filter out and use a weed burner to blow hot air directly into the air intake trick. I?ve started diesels like that in conditions that were not fit for a polar bear.

But I don?t think I would try either on my plane. Normally just a 100? cord and a call to the fbo to ask if there is a place I can plug my plane in. When it?s really cold, I also don?t mind paying $30-40 to park my plane in a heated hanger overnight.
 
Lots of interesting ideas here. I've over constrained myself somewhat in that I'm unwilling to have my wife and two toddlers mill around for a few hours while I wait at the airport for many of these methods to work. I don't think I'll be starting a fire on the ramp of most of the places I visit either. I now know that KTEX (Telluride) has free outlets on the ramp. KAPA is still an issue. The country's busiest GA airport doesn't really know what to do with piston singles in this case. I didn't press too hard, there's a good chance a more knowledgeable person on the phone would have given a different answer.

Given time to wait, I like the camp stove and duct idea in post #14. I even have that exact stove.

It turns out that Vic mentioned an elegant and less expensive method to what I was thinking of when I mentioned a Goal Zero battery pack in a post here: http://www.vansairforce.com/community/showpost.php?p=1230176&postcount=3

Basically, carry a spare battery and inverter to power my Reiff sump heater. I can even carry my cell phone activated switch if necessary.
 
I can raise temps about 10-15F in less than 30 minutes with a hair dryer, extension cord, and cowl blanket (old thin sleeping bag that doubles as survival gear). Just need to be able to find an outlet. That seems to be faster than a stick on pad/band system, it heats the whole engine, and is thus my current strategy while away.
 
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I'm all about the lightest possible aircraft, so permanent pre-heaters are out for me.
If operating at a Civilized Airport, I would use a 'Heat Gun' (looks like an industrial hair drier) and an extension cord. Direct it up into the bottom, set it on a stool...anything that comes to hand. It's the lightest thing, you could carry it in your flight bag.
In my hangar, I use a 120 volt plug in heater and flex aluminum clothes drier hose to bring the heat up to the exhaust outlet under the cowl. I cover the cowl with an old sleeping bag / blanket / tarp.
It fits *All* aircraft.
I have a Coleman stove, and plan to try Mike Baur's (post #15) camp stove and drier hose system. This is a mini system of every WWII combatant's winter pre-heater. This I would watch while using, but the supplied heat is plenty and the pre-heat time would be fairly short.
I know some think it's unsafe, put bear in mind that this is the same area that your exhaust pipes expel raw flame when flying. The camp stove flame is much farther away and lower. Position it a bit to the side and keep an eye on it, you'll be fine. (standard disclaimers of responsibility liability etc) Just be careful.
 
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If one does a comparison of weights I believe you'll find the stick-on pads to weigh considerably less than a hair dryer or heat gun.

The real difference is the speed of heating.

Watts in are what count for speed. A 1500W heat gun is going to be much faster than 300-600W of stick-on heating pad.

Yesterday I was in a bit of a hurry so used a 1000W heater in addition to the 650 total installed watts of the Reiff Turbo XP system. Then again, the ambient temperature was -22c in the hangar when I started... :)
 
Preheating with battery and inverter

Guy - what kind of battery life/heating capability are you getting? I've got a spare Odyssey PC925 and an inverter that I can devote to powering my Reiff (sump and piston rings). But I'm wondering if this system has enough oomph to get the job done. I hooked it up the other day and the inverter started beeping about a weak battery after only 10 minutes or so.

Guy Prevost said:
Lots of interesting ideas here. I've over constrained myself somewhat in that I'm unwilling to have my wife and two toddlers mill around for a few hours while I wait at the airport for many of these methods to work. I don't think I'll be starting a fire on the ramp of most of the places I visit either. I now know that KTEX (Telluride) has free outlets on the ramp. KAPA is still an issue. The country's busiest GA airport doesn't really know what to do with piston singles in this case. I didn't press too hard, there's a good chance a more knowledgeable person on the phone would have given a different answer.

Given time to wait, I like the camp stove and duct idea in post #14. I even have that exact stove.

It turns out that Vic mentioned an elegant and less expensive method to what I was thinking of when I mentioned a Goal Zero battery pack in a post here: http://www.vansairforce.com/community/showpost.php?p=1230176&postcount=3

Basically, carry a spare battery and inverter to power my Reiff sump heater. I can even carry my cell phone activated switch if necessary.
Click to expand...
 
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i would be hesitant to use a ''heat gun''. they get literally red hot.
a hair dryer has safer temps. also hair dryers can be had up to 1850 watts. that's a lot for an elec. heat source.
had my experience with a heat gun. trying to preheat a skidsteer. gun never left my hand and before it was over i melted a fuel line anyway.
 
Dugaru said:
Guy - what kind of battery life/heating capability are you getting? I've got a spare Odyssey PC925 and an inverter that I can devote to powering my Reiff (sump and piston rings). But I'm wondering if this system has enough oomph to get the job done. I hooked it up the other day and the inverter started beeping about a weak battery after only 10 minutes or so.
Click to expand...

a 150 watt heating element will draw approximately 12 amps at 12.5 volts. The inverter will likely have a 70% efficiency rating, ultimately requiring around 17 amps at 12.5 volts. Compare this to the AH rating on your battery. Be advised that AH ratings are typically given for low current levels (a 20 hour rating). You want the 1 hour AH rating for this application. These are quite a bit lower than the 20 hour rating, which is why they aren't adevertised.

Larry
 
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bobnoffs said:
i would be hesitant to use a ''heat gun''. they get literally red hot.
a hair dryer has safer temps. also hair dryers can be had up to 1850 watts. that's a lot for an elec. heat source.
had my experience with a heat gun. trying to preheat a skidsteer. gun never left my hand and before it was over i melted a fuel line anyway.
Click to expand...

Even a hair dryer or light bulb can and will blister the paint on a your nice fiberglass cowl very quickly if not used with care and attention. Heat guns are much hotter than that.

The stick on low wattage oil sump heaters and purpose made ceramic self regulated temp limit hot air heaters are much safer and gentler to your aircraft

YMMV
 
This is super useful info, many thanks.

So I've got a Reiff standard system - four 50-watt band heaters and a 100-watt HotStrip. If I'm reading the Odyssey specs correctly, the 1-hour AH rating for the 925 is 20 amps:

http://www.odysseybatteries.com/pc925_series.htm

So I'm guessing the system is giving the 925 about all it can handle, maybe a bit more, which makes my inverter beep. On the other hand, perhaps I'm getting pretty decent heating anyway. Time to test it out for a few hours.

lr172 said:
a 150 watt heating element will draw approximately 12 amps at 12.5 volts. The inverter will likely have a 70% efficiency rating, ultimately requiring around 17 amps at 12.5 volts. Compare this to the AH rating on your battery. Be advised that AH ratings are typically given for low current levels (a 20 hour rating). You want the 1 hour AH rating for this application. These are quite a bit lower than the 20 hour rating, which is why they aren't adevertised.

Larry
Click to expand...
 
alpinelakespilot2000 said:
I can raise temps about 10-15F in less than 30 minutes with a hair dryer, extension cord, and cowl blanket (old thin sleeping bag that doubles as survival gear). Just need to be able to find an outlet. That seems to be faster than a stick on pad/band system, it heats the whole engine, and is thus my current strategy while away.
Click to expand...

But has the crankshaft been warmed up in 30 minutes? That is one big hunk of steel buried deep in the engine with a huge heatsink bolted to the end of it hanging in cold air. Those crank journals are the biggest concerns during a cold start.
 
Sam Buchanan said:
But has the crankshaft been warmed up in 30 minutes? That is one big hunk of steel buried deep in the engine with a huge heatsink bolted to the end of it hanging in cold air. Those crank journals are the biggest concerns during a cold start.
Click to expand...

Good question, Sam. My CHT's show similar temperature rises, so I know the heat is soaking into the cylinders at least but I don't know what the internal temperature of the engine would be.

I agree that longer is probably always better but, rationalizing out loud, when one has an FBO do a preheat using a blower is it generally on long enough to heat the crankshaft? My suspicion is that unless heated for a long time, a lot of aircraft get heated up a bit unevenly.
 
Dugaru said:
This is super useful info, many thanks.

So I've got a Reiff standard system - four 50-watt band heaters and a 100-watt HotStrip. If I'm reading the Odyssey specs correctly, the 1-hour AH rating for the 925 is 20 amps:

http://www.odysseybatteries.com/pc925_series.htm

So I'm guessing the system is giving the 925 about all it can handle, maybe a bit more, which makes my inverter beep. On the other hand, perhaps I'm getting pretty decent heating anyway. Time to test it out for a few hours.
Click to expand...

Your pulling around 30 amps from that battery, which is a lot for it's size. It's no surprise that the voltage is dropping quite a bit and that is triggering your inverter to complain. You'll need to watch the low voltage cutoff on the invertor, as it might be high and would prevent you from drawing to the rated capacity of the battery.

Larry
 
Sam Buchanan said:
But has the crankshaft been warmed up in 30 minutes? That is one big hunk of steel buried deep in the engine with a huge heatsink bolted to the end of it hanging in cold air. Those crank journals are the biggest concerns during a cold start.
Click to expand...

Wear to the crank (it's usually the bearings that wear, not the journals) during cold starts is due to oil starvation and is unrelated to the temp of the crank itself; it's all about the oil temp. Cold oil gets thick and is much harder for the system to pump through the small galleries. This creates a delay in getting oil to the crank interface after start. As you may know, the crank rides on an .002" thick film of oil and that film layer cannot be maintained without positive oil pressure. Any engine rotation with power pulses without that layer will create wear to the bearing. The longer it runs before the oil film arrives, the greater the wear. The residual oil from last run slows down the wear for a bit, which is why you don't see much wear even with all of the starting.

Larry
 
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lr172 said:
Wear to the crank (it's usually the bearings that wear, not the journals) during cold starts is due to oil starvation and is unrelated to the temp of the crank itself; it's all about the oil temp. Cold oil gets thick and is much harder for the system to pump through the small galleries. This creates a delay in getting oil to the crank interface after start. As you may know, the crank rides on an .002" thick film of oil and that film layer cannot be maintained without positive oil pressure. Any engine rotation with power pulses without that layer will create wear to the bearing. The longer it runs before the oil film arrives, the greater the wear. The residual oil from last run slows down the wear for a bit, which is why you don't see much wear even with all of the starting.

Larry
Click to expand...

I don't have any interest in arguing the point, but here is a link to a Mike Busch article about how crank and cam bearing clearance is the biggest problem with a cold start:

https://www.avweb.com/news/maint/182846-1.html

This is a good read for anyone who needs to start a cold engine and wants more info on preheating. I suspect that many times the engine has not been heat saturated sufficiently after a brief session with a heater.
 
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