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Cordless Preheater - Test In Progress

avrojockey

Well Known Member
Patron
Normally I have oil sump heater plugged in to smart outlet at the hanger. However there are times when I need a preheat away from home and the FBO charges $90 to plug it in.

I played around with the MSR camping stove and that worked OK but setting up with proper ducting was lees than ideal.

I stumbled across another bush-pilot thread that used a diesel heater common in the boat/camper van world. Original US design was expensive, but the patent ran out and China has taken over. You get these for about $150 at the usually online suspects.

I'm still working out the ducting options but I can tell you that these put out considerable heat...like a little Herman Nelson, but it's clean and dry air as it's has a separate exhaust, so you can duct to the cabin for heat as well.

It runs on 12V so I plug it into an SAE plug I have hooked up to battery for charging/power supply. It pulls about 3 amps. I testing it on a health PC680 for 1 hour and though a little slower, started engine just fine. Heated oil from low 30s to 70 and CHTs to 55-65 in said hour

I'll post some picture when I finalize my ducting.
 

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Diesel heater

Keep us posted. I know several off roaders who use that in the 4x4. They say it will roast!
 
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It runs on 12V so I plug it into an SAE plug I have hooked up to battery for charging/power supply. It pulls about 3 amps. ...

This looks like a great solution, but kind of curious where the 3 amps are going - most 12v DC muffin fans are less than 1 amp.

https://www.mcmaster.com/muffin-fans/voltage~12v-dc/bearing-type~ball/

There are a few youtube videos discussing these heaters, and they seem to be quite positive. Can't say I'm too excited about having any kind of open flame just under my fuel tanks, but I guess if you watch it closely...
 
If you read some of the other airplane forums, it seems there has been a cottage industry pop up for these heaters.

They have a smaller version (5kw) that people are stuffing into a plastic toolbox, sort of like those toolbox vacuums you see people have. With or without the battery as part of the unit.

I'd be afraid to use my airplane battery to drive it on a regular basis, and people have reported that motorcycle/ATV batteries run it just fine (obviously you need to recharge that battery). The main power draw is when the glow plug is running on initial startup, then the amps drop down to about 1.5 (on the 5kw version).

It's not really an open flame per se, any more than any radiator heater is. The flame is completely contained within the unit, and the exhaust is separate, much more like the (propane) heaters they have used for eternity on travel trailers etc.

It's only a matter of time before someone makes a nice complete package of these with custom cowl inserts or whatever for each model plane and charges double for those that don't like to get their hands dirty :D
 
From what I gather from YouTube the one I have (8kw) is drawing just under 3 amps. The fan motor is quite a bit more robust...like the size of a cordless drill motor, so makes sense. It drives two fans...one for the heat exchanger and one for combustion air. It does draw about 9 amps during start up with the glow plug on...this lasts about 2 minutes. None of this I've measured...just what I've seen others measure on YouTube. Still testing the use of ship's power. May be better off with it's own battery pack I can charge in flight. Though I probably don't need to run it for a full hour like I did in this test. If I can get the oil up to 50-55 and CHTs at over 40 I'll be happy.

The combustion process is completely internal...extremely safe with some build-in protections. However the exhaust pipe gets very hot. I'm actually thinking about routing this exhaust for engine preheat only. It burns clean enough that my CO detector doesn't register any PPM when I hold it up to exhaust.
 
why not buy a stick on heater or 2? and a nice little generator. you could the generator in the off season a lot more than the heater?
 
I have one of these heaters I got last year for the same purpose. After some fiddling and fixing mine works ok at the lowest manual setting as it runs too rich at higher settings and will smoke. There are some variations to the controllers and the one I have with blue digits for the temp display do not allow changing the calibration settings for the pump as do other variations. Thought about getting another but an Amazon $20 500W heater plugged in has been working extremely well and would work well with a small generator.
 
also, isn't that outfit ''red dragon'' still in business? i think they still make the propane unit for less than $150. had one once and it worked perfect.
i have a knock off now of the red dragon. after i got rid of mine i bought one on craigs list, i think $50.
 
why not buy a stick on heater or 2? and a nice little generator. you could the generator in the off season a lot more than the heater?

I considered that option but finishing a work trip I don’t care to wait a couple hours before I can start…I’d like to have it preheated in 30 minutes. The diesel heater can do this. There’s also the possibility to turn it on remotely…have it all set up, when I land crank it up from my cell…by the time I get from the terminal to the FBO pay my bill, it’s ready to go. these units are designed to run unattended, or while your sleeping, for heat in your camper.
 
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also, isn't that outfit ''red dragon'' still in business? i think they still make the propane unit for less than $150. had one once and it worked perfect.
i have a knock off now of the red dragon. after i got rid of mine i bought one on craigs list, i think $50.

Goal is to remain as self-sufficient as possible when away from home. Propane is much more expensive per kWH than diesel, and maintaining a propane tank away from home doesn't seem the least bit practical. I'm not sure I like the idea of carrying a propane tank with me.

These units are highly portable, will burn diesel, jet or kerosene, and are marginally good at burning petrol if needed in a pinch. So, you can transport empty and fill with a little fuel at destination. I don't really see a better solution that doesn't require AC power.
 
although the red dragon won't run on a 1 pound bottle i am sure it would on an 11pounder. i had the model that runs on 12vdc.
 
More test results...this is 30 minutes preheating with close to the final configuration, and without a blanket...OAT was about 36F, and ambient temp in hanger was low-mid 40s...

  • Routed exhaust to the engine preheat air which is ducted under cowling, directed at oil sump
  • Air to cabin/cylinders is still clean dry air (no exhaust)
  • Scat tube seems to handle heat ok...gets hot enough you cant hold your hand on it more than a second
  • Clean dry air ducted to heater box exhaust through oil door adapter. This is normally plugged in the winter to insure max flow to cabin. Routing preheat air allows you to send heat to cabin or top of cylinders.

Results: If you look at the oil temp it came up about 40 degrees in 30 minutes. Kinda strange how the CHT temps reacted...not sure why they read this as they were not cold to the touch. Everything was pretty warm but an amazing amount heat was coming out around the spinner. Need to find out how to seal that off.
 

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Do you think the entire oil in the sump came up 40F in that short time or was it the oil sensor itself? I wonder what would happen to the oil temp if you started the engine and let the sump oil circulate past the probe.
 
Lithium inverter?

Aren’t we getting darn close to being able to buy a portable battery pack that would work with our plug-in heater elements? Use it, then just charge it back up later.
 
some foam strips 2'' wide and cut to the right thickness will seal all that between the spinner and the cowl
 
Do you think the entire oil in the sump came up 40F in that short time or was it the oil sensor itself? I wonder what would happen to the oil temp if you started the engine and let the sump oil circulate past the probe.

I have the ducting far into the cowling...right under the sump. When I did the first test I ran the engine to see just that. The oil temp dropped only 2 degrees right after start and started warming past the pre-start indication within 10 seconds. So, it appears all the sump oil is heating as hoped.
 
Aren’t we getting darn close to being able to buy a portable battery pack that would work with our plug-in heater elements? Use it, then just charge it back up later.

It's getting close...Jackery, Anker, and Bluetti make some nice units that produce the watt/hrs to power sump heaters for a couple hours, but they're a bit more expensive. Certainly more utility though.
 
These diesel heaters are great! They put out a ton of heat, and pretty reliable. There are a ton of videos on YouTube with different installations. I recently installed one in my JetExec helicopter.
 
I used this type of heater on a Tomahawk that I had and it melted the carb heat cable jacket. I won't use a hot air heater on a plane agin.
 
Portable energy systems (aka batteries)

Aren’t we getting darn close to being able to buy a portable battery pack that would work with our plug-in heater elements? Use it, then just charge it back up later.

We have three GOALZERO batteries that are recharged either by plugging them into the house current or solar panels, which is how we usually recharge them. We use them at OSH to recharge our phones and laptops but also to run fans in our tents when the nights get hot and sticky. Fans in our tents at OSH??? OH, yeah! We are very popular in our tent community for charging phones!

We have the small 100, larger 150 and 500 units, the larger said to be able to power a refrigerator for 8 hours, but we haven't tried that. I'm sure they would power a heater unit where electricity is not available. Other sizes are available as well, as well as the solar charging panels (free energy!). Mine are out being recharged as you read this. Great for camping as well.

In the Denver and Cheyenne areas you can find them at locally-owned JAX Mercantile (at 8 locations) as well as nearly anything else you need!
 
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