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  #1  
Old 02-19-2021, 08:35 AM
Dan Langhout's Avatar
Dan Langhout Dan Langhout is offline
 
Join Date: Mar 2008
Location: Huntsville, AL USA
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Default DIY Preheat using Oil Filled Heater??

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?
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  #2  
Old 02-19-2021, 09:08 AM
Desert Rat Desert Rat is offline
 
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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.
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  #3  
Old 02-19-2021, 04:36 PM
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Ironflight Ironflight is offline
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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
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  #4  
Old 02-19-2021, 06:10 PM
RV10Man RV10Man is offline
 
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Default

Here's my solution. I have it on a timer. About 3 hours and the engine compartment is nice and toasty. I also drape a couple of twin sized mattress pads/covers over the cowl.

https://www.facebook.com/photo/?fbid...335871&__cft__[0]=AZWu8cj5FTReFh6DAEsQl5LkoyCbeYdW6Eg3vO6I98gipaD4R CHPrDLNM935Tl1SL2B4U8Fc2xTBppLiV8PBjo1947xX_it7M6Q xKj50y-6HckVwluKrFMbmR5AX1UPD6G4&__tn__=*bH-R
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  #5  
Old 02-19-2021, 07:17 PM
David Z David Z is offline
 
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Location: Thunder Bay Ontario
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Default Buddy Interior Car heaters

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

https://phillipsandtemro.com/solutio...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.
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  #6  
Old 02-19-2021, 08:22 PM
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wjb wjb is offline
 
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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!
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  #7  
Old 02-20-2021, 06:31 PM
mbauer mbauer is offline
 
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Location: Nikiski, AK
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Default 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
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  #8  
Old 02-20-2021, 07:12 PM
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Dan Langhout Dan Langhout is offline
 
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Default 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.
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  #9  
Old 02-20-2021, 08:59 PM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
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Quote:
Originally Posted by Dan Langhout View Post
. . . . 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.
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  #10  
Old 02-20-2021, 09:23 PM
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Toobuilder Toobuilder is offline
 
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150 watt stick on pad heater from Amazon is $30 bucks. Does not get much lighter, easier or safer than that.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

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