Industrial Heated Blanket for Prehea

Discussion in 'Maintenance Bay' started by James Rivenbark, Jan 12, 2019.

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  1. James Rivenbark

    James Rivenbark Filing Flight Plan

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    Purchasing a 1962 PA-28-160, and will be on a tie down in Tennessee (due to lack of hangar availability and funds). 30SMOH, new cylinders (not sure if ECI or Lycoming), I want to avoid excessive wear. I'm looking into a 100°industrial heated blanket for preheat. Temps regularly get below 40°, sometimes below 30°, and every year we'll get a few days in the teens. Having spoken to the FBO, I have clearance to pull up and plug in the night before. Will be using a moving blanket around cowl with bungee, and cowl plugs. Don't care to insulate prop.
    Would something like this be acceptable for a one hour (not plugged in overnight) preheat in 20°-30° (they also offer a 150° blanket)? Or, should I stick with the 100W bulb overnight? FBO doesn't offer propane services or hangar one night prior.


    https://www.globalindustrial.com/p/...uty-flat-heating-blanket-md0304g-120v-5l-x-4w

    -JR
     
  2. kyleb

    kyleb En-Route PoA Supporter

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    For an overnight preheat, you'd be much better off with a Reiff sump pad or strip. Others make similar products. They don't require an A&P for installation, but you do need access to the airplane's sump.

    If you're looking for a 1 hour preheat, you could combine one of the sump pads to heat the oil with an electric cube heater ducted into the engine compartment. That would do a reasonably good job of heating the cylinders and case, although the crank might not see a lot of temperature rise. Even better, a propane preheater would push a lot more hot air through your cowl, but now you're talking a fair amount of support equipment (heater, propane tank, electricity).
     
  3. James331

    James331 Touchdown! Greaser!

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    This is for continental, but worth a read.

    http://www.continentalmotors.aero/xpublications/xservice bulletins/pdfs/sil03-1/
     
  4. kyleb

    kyleb En-Route PoA Supporter

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  5. James331

    James331 Touchdown! Greaser!

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  6. Cluemeister

    Cluemeister Line Up and Wait PoA Supporter

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    I have the twin hornet 22, works great in Tennessee.
     
  7. tawood

    tawood Pattern Altitude

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    I'd be willing to bet that an hour like this would only raise the temp of the engine a degree or two at best. If you really want to pre heat it, put an oil pan heater on it.
     
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  8. tawood

    tawood Pattern Altitude

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    BTW, for the cost of that pre heater and thermostat, you could easily have a mechanic put a heater on your oil pan, and still have some change...(I just priced aircraft pan heaters...its been awhile...you'd actual have a LOT of change left over)
     
  9. 455 Bravo Uniform

    455 Bravo Uniform Pattern Altitude PoA Supporter

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  10. James Rivenbark

    James Rivenbark Filing Flight Plan

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    If this link doesn’t work because I’m new around these parts, go look at a Ryobi 18v one+ hybrid forced air propane heater. I think I’ve decided, this plus a duct, and I’m good to go. Completely assembled and full, 10lbs. Good for 1.5 hrs. Would easily fit in baggage compartment. Self contained electricity and propane. Would make for great overnight trips, and great to keep in the trunk/friends hangar.
     
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  11. GRG55

    GRG55 Final Approach

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    My first plane was a '61 Cherokee 160. I used a quilted cowl blanket and an electric cube heater with a small fan placed on the bottom cowl so the air circulated up onto the oil pan and through the cylinders. Set it up on a timer to start 3 hours before I planned to arrive to go flying. I live in the Rockies and temps get pretty chilly here. This set up worked beautifully.
     
  12. Stewartb

    Stewartb Final Approach

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    An electric blanket will heat the cowl, not the engine. Very inefficient. If you have access to electricity a Zero Start Little Buddy heater is the best temporary heater I know of. Metal case, overtemp protection, and no tip switch. Electric heat is always better than propane. No water vapor.

    Using the proper oil for the temps is more important than the heater given the conditions you’re describing and the heaters you’re considering.

    https://www.amazon.com/Zerostart-2600900-Interior-Electric-Portable/dp/B000NM73ZA

    FYI- https://www.lycoming.com/sites/default/files/Cold Weather Starting.pdf
     
    Last edited: Jan 13, 2019
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  13. GRG55

    GRG55 Final Approach

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    Like @Stewartb, I am not a fan of blowing hydrocarbon combustion products across my engine. Exhaust gasses are corrosive.
     
  14. 3393RP

    3393RP Pattern Altitude

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    The combustion products of propane are significantly different from those of a gasoline powered internal combustion engine. Have you ever disassembled a properly tuned propane powered engine fitted with effective air and oil filters? The internals look new, even after thousands of hours of run time.

    I wouldn't have any problem with using the Ryobi heater.

    Complete combustion of propane results in the formation of carbon dioxide and water vapour. Carbon monoxide is a by-product of combustion when there is not enough oxygen to burn the propane completely.

    https://www.ccohs.ca/oshanswers/safety_haz/forklift/propane.html
     
  15. GRG55

    GRG55 Final Approach

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    Yes, I am very familiar. But you still won't catch me blowing hydrocarbon combustion byproducts over my expensive aircraft engines.

    I used to be the Managing Director for the Middle East & North Africa region for one of the largest global LPG trading companies. Propane is pretty clean, but it also isn't ever pure C3.
     
  16. Stewartb

    Stewartb Final Approach

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    Propane exhaust hitting cold metal makes water. Water inside the starter, alternator, etc. Water forms on the cowl... Warm air in general heats air cooled cylinders quite well but barely makes a rise in oil temp unless you use it for several hours. There are better choices available. Much better.
     
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  17. James Rivenbark

    James Rivenbark Filing Flight Plan

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    I should’ve specified, I would be placing the 100° or 150° blanket underneath the engine, either laying down on the cowl, or secured around the engine with a bungee strap effectively creating a warming wrap around the engine. I have the large cowl access panels, when open, there is more accesss than blocked space. Using Phillips 66 XC 20W-50 with ASL CamGuard. Additionally, If warm air creates condensation, I assume that air from a ceramic heater would produce the same condensation, but due to lower BTU’s, be around longer before the engine can burn it off because it will take longer to preheat. Thank you all for the quick and thoughtful responses
     
  18. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

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    Combustion of hydrocarbon fuels such as propane, gasoline, etc. produces water in the exhaust which can then condense as it cools. A ceramic heater does not produce water - it just heats the air.
     
  19. AKBill

    AKBill Pattern Altitude

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    That's reason I don't use my Red Dragon to much. EZ oil pan heater is a good start for your weather.
     
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  20. GRG55

    GRG55 Final Approach

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    As @Stewartb pointed out, the blanket will heat the cowl nicely. Unlikely you will warm the engine very efficiently. An aircraft engine is air cooled when operating. To heat it efficiently when it is cold you need to reverse the process. That means a combination of convention and conduction heat transfer.

    Your conclusion about the condensation is incorrect. Heating the air with an electric resistance heater lowers the relative humidity and discourages condensation. The forced draft from the heater fan improves the convective heat transfer to the engine cylinder fins, which conduct it to the internals.
     
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  21. flyingbrit

    flyingbrit Pre-takeoff checklist

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    Natural gas powered clothes dryers use a mixture of ambient air and combustion gases much like the Red Dragon and Ryobi. How bad can that be?
     
  22. tawood

    tawood Pattern Altitude

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    I don't understand...why use something expensive and not meant for planes, when there are much cheaper heater options that ARE meant for planes?
     
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  23. PaulMillner

    PaulMillner Pre-takeoff checklist

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    >> The combustion products of propane are significantly different from those of a gasoline powered internal combustion engine.


    Well, no, they're not... primarily CO2 and water. Combine those two, and you have weak carbonic acid, which does a nice job of eating metals.


    >> Propane is pretty clean, but it also isn't ever pure C3.


    I don't think propane impurities are an issue; what species are you supposing appears in propane exhaust that's so pernicious? The normal combustion products, water and CO2, are the worst actors, typically.


    >> Propane exhaust hitting cold metal makes water. Water inside the starter, alternator, etc. Water forms on the cowl... Warm air in general heats air cooled cylinders quite well but barely makes a rise in oil temp unless you use it for several hours.


    >> If warm air creates condensation, I assume that air from a ceramic heater would produce the same condensation


    Nope, that's not how it works. Warm air doesn't create moisture; combustion creates moisture.


    >> Natural gas powered clothes dryers use a mixture of ambient air and combustion gases much like the Red Dragon and Ryobi. How bad can that be?


    If your clothes are made out of metal, you may find out as they corrode away. But I prefer cotton.
     
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  24. James Rivenbark

    James Rivenbark Filing Flight Plan

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    Thanks to all that responded. After some serious thinking and trying out a ceramic space heater, electric forced air heater, propane heat exchange forced air preheater, and looking at oil pan preheaters on some flight school airplanes, we've decided to go with the EZ Heat Oil Pan Preheater 440. In the future, I would like to move up to cylinder heaters on a Reiff or Tanis alongside the oil heater, but for now, in the temps we'll be operating at, we think this will work well.
     
  25. murphey

    murphey Final Approach PoA Supporter

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    Remember to clean the oil pan with some sort of solvent to remove oil and crud, otherwise the adhesive is useless.
     
  26. iflyvfr

    iflyvfr Pattern Altitude

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    MEK will do the job on the oil pan. But I don't understand all this talk about eating your engine with a little pre-heat. You're going to get in the plane once it's warm and fly anyway. Caustic ignition byproducts are not being blown into the engine internals after all. I know some have big, expensive engines, but mine is so liberally coated with engine oil the worst these so-called engine eaters could do is degrease it, not consume it. Having used most of the recommended solutions I'd still go with a timer and a heater pad on the sump. I also like to bring a quart of warm oil and dump it in before I fly.
     
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  27. Clip4

    Clip4 En-Route

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    Drain the oil, take it home, keep it warm, put it back in.
     
  28. ahypnoz

    ahypnoz Pre-takeoff checklist

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    Better Yet,
    Buy a Presto 6 quart oil fryer and
    drain it using a quick release drain right into the fryer.

    Next day when u want to fly, heat it up (home or hanger) and add it to airplane before flight. Use a metal funnel.

    You can buy one for $34.95 at Bed Bath and Beyond or I can sell u an aviation one for $134.95. It come with an airplane sticker on the presto box.

    (Use oven mittons and protective eyewear and gear)
     
    Last edited: Jan 17, 2019
  29. Huckster79

    Huckster79 Line Up and Wait

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    Preheating is a deep subject, way more concern than oil alone. No, improper preheating will not pull you out of the sky but doing it right may stay off the overhaul job...

    Here is what I wrote on the Cessna 120/140 forum, one of the more knowledgable guys and mechanics said it was pretty spot on...

    Preheating is far more complex and in depth topic than i undedstood it to be! Its not really about having goey oil.. its bearing clearance in the bottom and keeping pistons from scoring up top and condensation issues...

    From what i can gather under 40 its time, but wouldn't hurt at any temp though in actuality, and its a mortal sin in the 20s and under to not preheat...

    So heating bottom end is vital as cold oil isn't as much an issue w multi viscosity aviation oil as the fact that the aluminum block and steel crank don't proportionately shrink with the temp, so the bearing clearances are squeezed below their factory designed minimums with the aluminum shrinking more than the steel to the point its so tight that their is no room for oil and metal is kissing metal... so gotta make sure bottom is warm. This can't be done with a 20 minute blast...

    Now up top our piston walls are not parrallel with each other at cold temps, instead there is a slight conical shape to our bore with the top being narrower. This is built in by design because air cooled cylders dont hold the same temp at bottom as they do the top under normal operting condition. So our cylinder walls lose their cone shape as they reach operating temp and their tops are hotter than their bottoms... so started cold, that piston is pushing up into a cylder too small at top for low wear operation. One engine "expert" i read said a single cold start can put as much wear on cylder walls as 500 hours of cruise flight...

    Now condensation... the ford vs chevy argument in preheat is: on all the time vs on just as long before you need it as neccesary..the issue is an engine that's toasty down bottom but freezing up top is somewhere in that engine is an area at dew point now... engines are humid inside, a byproduct of combustion and some blow by and such... so theres risk with a continually heated engine if theres a significant temp differential within it of creating condensation to sit on engine parts-not good. Thus some preheat just long enough to get to temp, length dependent on environment and equipment capabilities, minimizing the time that condesation is in there on parts that are daily loosing thier oil coating....

    I think the truth is in the middle, if you can heat your engine to an even amount and above dewpoint danger, preheat around the clock. If you can't, preheat when necessary just before flight but long enough to get her warm in and out. And if one does the "just long enough" method and cancels flight, better to try to get even temp on engine (covering it all up) and let preheat stay on till next flight however long that may be, as cooling it again brings it through dew point after being unused so not getting coated in oil again, so best to leave it on till next flight. I understand it may not always be possible- these are just theoretical ideals.

    I'm going to sew her a cowl cover custom to wrap cowl including the front, and make propeller covers as well, as the prop and spinner act as a huge aluminum heat sink for the engine. A heat sink is the metal cooling device used on electronics to passively cool them by radiating off heat, prop does same thing to our engine in preaheat... I don't think the prop covers are a necessity but I view the cowl cover or wrapping it with blanket is...

    So long and short of it: its never really too warm to preheat, when in doubt do it. A preheat thats truly effective will get top and bottom warm whatever method one chooses. Be conscous of condensation and find a way to best mitigate its danger. There's also a thread on engine dehydrators on here, thats not an entirely unreleated topic...

    Again this is off google research (though a lot of it) and triangulating forum arguments on method not first hand knowledge yet. Take it for what its worth...
     
    Last edited: Jan 17, 2019
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