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DIY Preheat using Oil Filled Heater??

Dan Langhout

Well Known Member
Has anybody explored (or built) an engine pre-heater using a portable oil filled electric heater? You know, the ones that look like old fashioned radiators?

Seems to me this might be a reasonably safe approach given the fairly low surface temperatures of the fins, no exposed glowing heating elements, etc. The thought experiment approach would be to fabricate a sheet metal enclosure on one side of the radiator with a pair of 4 inch round outlets on the top of the enclosure to attach scat tube or similar. Tubes would then feed cowl inlet openings via convection.

Any ideas, comments, experience?
 
Since warm air rises, it seems to me that if you depend on just convection, it's likely that the top of the cowl will be nice and toasty, but it isn't going to do much for the cylinders or the oil in the sump.

If you attached some sort of blower to force that warm air down through the cooling fins and out the bottom, then I can see that approach having potential.
 
Dan - I’ve seen at least one person who built a duct that went over the kind of heater you talked about, and mated up to the bottom/back cowl opening - and did a great job of heating the engine compartment!

Personally, I stick a shop light with a 150 watt incandescent bulb installed up that opening and hook it on an entering cable overnight, when I expect cold temps and an early morning fight. It also works great!

Paul
 
Buddy Interior Car heaters

I have seen and used these little heaters on a plethora of piston aircraft engines:

https://phillipsandtemro.com/solutions/specialty/cab-cargo-heaters/

When I flew Navajos, we'd put one in the engine cooling air intake aimed at the oil sump. It's an up-draft cooling system, so the cooling air intake was looking at the oil sump and bottom of the cylinders. Wrap the cowl in an engine blanket, and it seemed to work down to at least -30*c (-22*f). Much colder than that, and we left the planes in the hangar, too cold to fly. I've seen those heaters used on piston Beavers too, although not down that cold.
 
I didn't specifically use the oil-filled heater to pre-heat the engine, but did use it to help speed up some epoxy curing on the cowl. I put the heater under the cowl the night before and made a tent with moving blankets to keep the heat in.

The next day, the epoxy on the cowl was nicely cured. I checked my G3X temp readouts out of curiosity, and found all temps (CHT, EGT, Oil T) all about 74 F. Pretty effective pre-heat (OAT was probably in the low 50's in the hangar .. not really fighting too hard against Mother Nature here).

I've used the oil-filled heaters quite a bit to help my epoxy projects cure overnight ... big fan!
 
Hair Dryer

Cheapest way to preheat?

I use three portable hair dryers. Cost was $11 each.

Two go in inlet openings running on low 750watt setting, Spin prop to hold in place.

The third one is bungy corded into the bottom cowling opening where the exhaust pipes exit. This one is heating at the high 1500watt setting. Warming the oil, battery and everything else under the engine.

Mike
 
Thanks . . . . .

. . . . for the responses folks! I think I may do a little prototyping and collect some temperature data just to amuse myself. I'm looking to end up with something I would feel good about operating unattended in the hangar.
 
. . . . for the responses folks! I think I may do a little prototyping and collect some temperature data just to amuse myself. I'm looking to end up with something I would feel good about operating unattended in the hangar.

Similar to what Paul mentions above, I use 2 75W light bulbs in shop light cages face down inside bottom cowl at exhaust exit. Put a blanket over top of cowl and it Easily warms entire engine 40-50F over ambient. Can’t imagine anything safer to leave unattended short of the preheat systems you install on the engine.
 
150 watt stick on pad heater from Amazon is $30 bucks. Does not get much lighter, easier or safer than that.
 
Heat gun and scat...

Takes me 30 minutes to increase CHTs 30 degrees.

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I have used this setup on my last couple of airplanes. In 2-3 hours it has the entire engine compartment very warm. I usually see oil temperatures between 65-85 when I start the engine.

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I use a Kats 250 watt 120 VAC heater with the magnet removed and JB welded to the sump on my 0-320. Cover the top cowl with a packing blanket and plug the inlet openings. Keeps the oil at 75° all winter. Has built in thermostat. R and R when engine overhaul. Stolen from an RV-er with one on his 0360 with 1100 hours.
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Keith RV7
Donation 2021
 
Cheapest way to preheat?

I use three portable hair dryers. Cost was $11 each.

Two go in inlet openings running on low 750watt setting, Spin prop to hold in place.

The third one is bungy corded into the bottom cowling opening where the exhaust pipes exit. This one is heating at the high 1500watt setting. Warming the oil, battery and everything else under the engine.

Mike
I don’t have electricity in my hangar and looking for a quick and easy way to preheat. How long does the hair dryer trick take. I’ll be using a potable generator. Thanks in advance. Any other ideas welcome.

RV-8 - Just purchased
 
This is working well for me. With a foil faced thermal blanket I went from 20 degrees outside to 90 degrees carb and 71 degrees oil after being plugged in overnight.
 

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I don’t have electricity in my hangar and looking for a quick and easy way to preheat. How long does the hair dryer trick take. I’ll be using a potable generator. Thanks in advance. Any other ideas welcome.

RV-8 - Just purchased

I've used two blow driers and a sump heater in the past for quick preheats. 15 minutes really helps in the Georgia climate, but it would take longer in colder climates.

I'd definitely add the sump heater if I was you. You get direct heat on the sump/engine/oil. With blow driers poked through the inlets, you're primarily heating the cylinders.
 
You get direct heat on the sump/engine/oil. With blow driers poked through the inlets, you're primarily heating the cylinders.

Exactly. I have a plenum so maybe it works better for me but I am happy with how it works. So, why did I order a 3'x5' heated sidewalk pad to strap to the bottom of the cowl!!

I will let you know how that works.
 
What's the most efficient way to do it?

Some ideas sound like they would use lots of electricity (hair dryers).....
 
in the past i tried a light bulb in a coffee can to heat the water for birds.........anyway as i remember a 60 watt bulb would at the least char cardboard if it came in contact. just sayin' you should be aware of the potential of what you use.
 
Middle of nowhere

Has anyone found a good portable solution for preheating on a ramp when no electricity is available? A portable generator would likely solve the problem, but is hard to carry around in the baggage area. Is there anything battery powered that can generate enough heat? Perhaps the solution is a unicorn.
 
Has anyone found a good portable solution for preheating on a ramp when no electricity is available? A portable generator would likely solve the problem, but is hard to carry around in the baggage area. Is there anything battery powered that can generate enough heat? Perhaps the solution is a unicorn.

The things I recall people mentioning are:

  • Automobile with connection from exhaust pipe into cowl
  • Camping stove with hood that funnels heat into cowl
  • small, lightweight generator

I guess it depends on where you are and how often this is an issue. If I had to deal with no electricity and frequent need to preheat at my home base, I'd probably build a propane or other fuel powered heater with a long duct so that there's no chance of lighting up the fuel in the aircraft, or get a generator.

Even with the weight, I think a portable generator would be a good solution since it can be used with so many other things, and the electric heaters could also be used to heat the cabin, if needed. And it's safer - just make sure it's securely tied down when flying in case you land off field.
 
Has anyone found a good portable solution for preheating on a ramp when no electricity is available? A portable generator would likely solve the problem, but is hard to carry around in the baggage area. Is there anything battery powered that can generate enough heat? Perhaps the solution is a unicorn.

I have an old Coleman Survivalcat I use in my Comanche. No open flame so pretty safe. That and a moving blanket taped to the cowl.
 
Has anyone found a good portable solution for preheating on a ramp when no electricity is available? A portable generator would likely solve the problem, but is hard to carry around in the baggage area. Is there anything battery powered that can generate enough heat? Perhaps the solution is a unicorn.

My first line of defense is a good quality insulated cowl cover. If I put it on ASAP after parking and I've found it keeps my engine warm enough for my typical day trip with no additional heat added. (maybe 3 hours in 10-20f typically; if I'm going to be longer than that I'm looking for an outlet)

for longer trips I've yet to find an airport up here in cold country that I can't find electricity that a 100ft cord can't reach to plug the sump heater in. I'll recommend from experience to buy a lighted cord so you know you're not plugged into a dead outlet.
 
Good tip

Good idea on the cowl cover for shorter trips.

I've yet to find an outlet with 100ft of any of the parking spots at KXLL, one of my frequent destinations. They will put it in the heated hangar but that's like $50 a night and I'm a cheap *******. Also, you get massive windshield fogging when you roll outside in the morning. :)

My first line of defense is a good quality insulated cowl cover. If I put it on ASAP after parking and I've found it keeps my engine warm enough for my typical day trip with no additional heat added. (maybe 3 hours in 10-20f typically; if I'm going to be longer than that I'm looking for an outlet)

for longer trips I've yet to find an airport up here in cold country that I can't find electricity that a 100ft cord can't reach to plug the sump heater in. I'll recommend from experience to buy a lighted cord so you know you're not plugged into a dead outlet.
 
I've yet to find an outlet with 100ft of any of the parking spots at KXLL, one of my frequent destinations.

Have you asked them? In my experience the outlets usually aren't near the parking spots, but on the exterior of the FBO building and/or hangar; just nose up to the outlet and use chocks. With that said, XLL looks more urban with less ramp extra ramp space than the airports I typically visit up here in MN so maybe they won't like that.
 
Has anyone found a good portable solution for preheating on a ramp when no electricity is available? A portable generator would likely solve the problem, but is hard to carry around in the baggage area. Is there anything battery powered that can generate enough heat? Perhaps the solution is a unicorn.

I'm developing a product to solve this!

I had the same problem. I'm tied down on a ramp and the airport doesn't have a heater, so I built one. My basic requirements were:

  • Small enough to be transported in a car and/or plane
  • Had to run completely independent of power
  • Had to be light enough to be carried in the plane without major weight concerns
  • Had to be stable enough to be safe for transport

Below are some pics of my prototype. Forgive the Mooney it's heating. I'm still building my RV. :) I've shown it to a few people and everyone who has seen it seems to be impressed, so I'm working on it in my free time to make it a sellable product. It works well for me. I live in SC so it doesn't get too cold. It's crude and needs some further development for it to be viable in the open market. I'm working on developing it further and giving it more functionality/usability. Some of the current specs:

  • Oulet air temp is around 200F (measured at 55F ambient)
  • Size is approximately 12x12x22
  • Weight is approximately 24lbs
  • Provides about an hour of heat on a full tank/charge
  • Approximately 17,000btu
 

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For those of you who want hot air heating, a cheap chinese diesel air heater could be made to work.
 
My Solution

$19.99 Walmart heater, floor HVAC register cut to splay out front
foil HVAC tape, dryer exhaust hose. Cheap timer set to come on two hours before departure. I push it over left exhaust, and plug the cowl. Works in my hangar, in Georgia.
 

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I made this 4 yrs ago and still going strong. I brought it down from the loft today. a couple options for heat source.

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LOW risk reliable pre heat

For what the value of your Lycoming and cowling are worth, these heaters are limited to 75deg F. https://www.aircraftheaters.com/aircraftheaters

No blistered paint on your cowling, and no worries.

https://youtu.be/LeEs1OflYtc

Phillips and Temro also make self adhesive oil sump heaters in various wattages to match sump volume. I have used these on several aircraft and diesel gen set engines over the years and they work great for very low power draw.
 
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I'm developing a product to solve this!

I had the same problem. I'm tied down on a ramp and the airport doesn't have a heater, so I built one. My basic requirements were:

  • Small enough to be transported in a car and/or plane
  • Had to run completely independent of power
  • Had to be light enough to be carried in the plane without major weight concerns
  • Had to be stable enough to be safe for transport

Below are some pics of my prototype. Forgive the Mooney it's heating. I'm still building my RV. :) I've shown it to a few people and everyone who has seen it seems to be impressed, so I'm working on it in my free time to make it a sellable product. It works well for me. I live in SC so it doesn't get too cold. It's crude and needs some further development for it to be viable in the open market. I'm working on developing it further and giving it more functionality/usability. Some of the current specs:

  • Oulet air temp is around 200F (measured at 55F ambient)
  • Size is approximately 12x12x22
  • Weight is approximately 24lbs
  • Provides about an hour of heat on a full tank/charge
  • Approximately 17,000btu


Hey, I've built one just about like this! Even has the same controller - except mine is in a DeWalt toolbox. Its a china diesel heater, has a 1 gallon diesel tank in the toolbox and I ran jumper leads out to connect to an old car battery. Works really well....
 
Hey, I've built one just about like this! Even has the same controller - except mine is in a DeWalt toolbox. Its a china diesel heater, has a 1 gallon diesel tank in the toolbox and I ran jumper leads out to connect to an old car battery. Works really well....

Yep. That's it, except it has a battery built in so it's totally self contained. I've been working on a new controller that gives you better feedback on it's function.
 

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open cabin heat

when I open cabin heat to half I get some preheat air coming thru to the cabin. call your airplane a couple of hours ahead to get preheat going and it will be nicer when you arrive.

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My kids wanted a suggestion for my Christmas gift, I requested the following space heater from Amazon:

https://www.amazon.com/Comfort-Zone-CZ707-Personal-Settings/dp/B0007ULR14

The mini space heater has a thermostat, 3 speed settings and overtemp protection. My intent was to make a duct and cowling and pipe the heat into my engine compartment (RV-9A). But as I looked at it, then at the oil door on the cowling, they seem to be virtually identical sizes! Turns out, the legs and handle are in perfect positions to support the unit at the oil door entrance! I set the thermostat to about halfway, fan to max. On Monday, when the temperature in the hangar was 30 degrees, the entire engine compartment was toasty warm (had to use a rag over my fingers to check the oil...dipstick was too warm!) and it started on the first turn. Oil temp at startup was 120!

Highly recommended, here's my YouTube video:
https://www.youtube.com/watch?v=s-c_XGBy0ig

I run it from my smart plug at the hangar, so I can turn it on and off from home via my cell phone.
 
Heater

Guys, I have come up with the best way to pre-heat your engine! There is a device called a Din heater. DIN is a DIN Rail system used in electrical cabinets. There are many different devices that fit on a DIN Rai System but you can also buy heaters that are small, durable and many explosion proof. The wattage varies, some come with built in thermostat and some you add. The benefit of these units are they fit inside the cowling, oil door ect, and it circulates warn air, the hole engine gets warm,, every part, the engine thinks its 75 degrees, no hot spots!
I use a 400 watt unit with a therm a attach to the bottom, it is small enough to go though the oil door I made a bracket that slides down though the oil door low enough so it hits the lower part of the engine, I plug it in the night before, cover the cowl with a blanket and all is good!

I don't remember where i got it but if you type in DIN Heaters there many companies that sell them.
Paid 2022
 
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