The International Cessna^® 170 Association

George,

Forum: 1. the public square or market place of an ancient Roman city or town, where legal and political business was conducted. 2. a law court; tribunal. 3. an assembly for the discussion of public matters or current questions.

Pontificate: 1. to officiate as a pontiff 2. to behave in the manner of a pontiff; be dogmatic

I stand by my previous post. Smiley face or no.

George, what you suggest as widely accepted means to pre-heat aren't as effective in the Arctic as they may be in Texas. The method you describe is not widely accepted, nor is it necessarily good operating practice, nor will it actually work in truly "cold" temperatures. Could you please offer the reference which suggests that this is good operating practice, please? I for one, have spent a lot of time perusing annals of arctic operations, and I've never actually seen mention of what you describe. Reference, please?

The problem with putting a heater outside the cowling is that heaters are simply designed to elevate the temperature of incoming air, and to eject warmer air. If the outside air temp is really cold, your method may not adequately heat the engine, because the heater will be drawing in really cold air and turning it into merely cool air, not actually warm enough to adequately heat the engine.

To properly heat an engine with a fan forced heater in cold, as opposed to cool, temperatures, you need to put the heater inside the cowling. This permits the air to recirculate within the cowling, and be heated and re-heated repeatedly. Do that with a fan forced heater, and you risk fire. That is a fact, though it doesn't happen bery often.

And, of course, it requires an engine blanket of some kind as well, which you noted.

If what you are doing is trying to take an engine from an ambient temperature of +20 degrees (or +15, or ???) to +50, your technique will work fine, and may in fact be a great way to pre-heat. But, what if you take the airplane on the road? You have to now carry not only the heater, the engine cover, an extension cord, and the cobbled up stovepipe, all inside the airplane.

See http://www.tanisaircraft.com for a pretty good discussion of pre-heating, which, by the way, doesn't particularly agree with your assertions either, regarding cylinder heat. Apparently, I'm not the only one.

And, it gets cold where they live, too, by the way. I'd commend anyone thinking of pre-heating to go there and read their comments. Now, understand that they sell engine heaters, so their assertions against the competition may be slanted a bit, but this is a great general discussion of pre-heating engines.

Both the Tanis and the Reiff heat systems have some engineering and testing behind them, they have no moving parts, and the likelihood of lighting your airplane on fire with one is really, really low. And, I would point out that they have tested their oil sump heat pads on engine oil pans in warm tempertures as well. Minnessota can get pretty warm in the summer. In fact, as a side note, I've flown up here in +103 degree temperatures, on floats (as in it doesn't get much worse than that), with no oil temperature problems at all, WITH an oil pan heater installed. Imagine that.

George, your original comments regarding the Tanis system are incorrect. Tanis uses a much more comprehensive approach than you let on in your post. It is a good system, and so is the Reiff system. Again, see the Tanis web site for a full description of their product. It is truly a "system".

If you live, fly and work in cold country, as I do, your method won't work. A lot of folks use fan forced heaters up here, and have good luck with them, but they put them inside the cowling, with a tightly closed cowl cover installed. Personally, I don't like the fire risk associated with these little furnaces, but they work for many many hours without trouble, and a lot of people use them, but not the way you advocate.

I prefer the installed systems, and I have a plug built into the side of my airplane (I know: MY HEAVENS!!! Stressed skin!!!). When I get somewhere with power, all I have to do is put on the engine cover, plug my extension cord into power, and into the side of the cowling of the airplane. The plug on the cowling is also equipped with a small red lamp on the outside of the cowl, so I can drive or walk by in the night and verify that the electricity is on, and the engine is getting heat. That is a comforting feeling when you are parked on the ramp in Fort Yukon for a week at a time, working in -20 or colder temperatures, or worse. I have used a Tanis pre-heat system at least once when the ambient temperature was -58. After having been plugged in all night, the engine compartment (as in all parts of it, including the firewall) was warm to the touch, and ready to go (I don't advocate flying in those temps, but that was a medevac flight, and going to warmer temps).

I have no problem with your methodology at all, for the conditions that you face, and if the only place you ever pre-heat is at home.

Now, if you have to pre-heat where there is no electricity, follow Mit Greb's suggestions in an earlier post.


Forum: 3. an assembly for the discussion of public matters or current questions.


So, for what its worth, which may not be much, especially if you live in south Florida.

Fairbanks is forecasted to hit -50 tonight, currently -36 F. No flying tomorrow.

Mike Vivion

I'm beginning to see what you mean by pontificate.

As for:

mvivion wrote:Could you please offer the reference which suggests that this is good operating practice, please? I for one, have spent a lot of time perusing annals of arctic operations, and I've never actually seen mention of what you describe. Reference, please?

Perhaps you could let the Air Force, Air Lines, and most FBO's up north have the benefit of your insight that their Herman Nelson type forced-air heaters are unknown, ineffective, and anyway, that forced air heat did not really do what they saw for the last 50 years.
(Not to mention our own members here who've already posted their hot-air systems such as Northern Companion, Red Dragon, both offered by Kennon's Aircraft Covers, by the way.) http://www.nationalguild.com/KennonAirc ... tions.html
http://www.ultimategear.com/airpreh.html

George,

Ah, so sorry: I thought your first post suggested you were referring to a small fan forced air heater, as in electric type.

Now you're talking about combustion heat, not electric heat. That is a very different subject than what I was discussing, and I would point out that a Herman Nelson won't fit in the back of some of the pickup trucks around, let alone be carried around, or procured for use a few times a year.

As I noted reference Tim Berg's post, there are several types of combustion heaters available for use in remote areas. Every single one of them (with the possible exception of the Herman), unless monitored carefully and constantly, has the very real potential of lighting your pride and joy on fire. I don't use combustion heaters IF electricity is available, for that reason. Some folks do, and that's fine, but they'd best be paying close attention during the heating process.

Oh, yeah: I've also seen the paint melted off the cowling of at least two airplanes with combustion heat applied a bit too enthusiastically by an inattentive pilot (otherwise known as someone who was trying to find a warm spot while waiting for the preheat to complete).

Also, all combustion heaters, except Herman, put a LOT of moisture into the engine compartment. That can be problematic, particularly if you end up not running the engine for some reason, which happens occasionally.

So, if you like combustion heat, go for it, but understand the fire risks, even if you separate the combustion source a good distance from the engine compartment, and keep a fire extinguisher handy.

One of the advantages of the Tanis and Reiff systems is that they are safe, they require little if any monitoring, they weigh practically nothing and they stay with the airplanes.

If you want to haul a Herman around, more power to ya. If you have a hangar, or tiedown with electricity nearby, combustion heat makes no sense at all to me.

But I've never been to Greenland. Flew over there once, though.

Mike

gahorn wrote:It may seem so...but I don't appreciate someone that doesn't know me or my background try to imply that because I don't live in Fairbanks that advice based on well-founded and widely accepted methods on preheat is "pontificating"..

George:

Living in Fairbanks means that a person has likely experienced brain freeze. They are generally really nice people but sometimes during the winter they begin to exhibit signs of Arctic madness. They mean well and will usually recover in early March.

I don't have electricity so I have to go the old fashioned route to preheat., i.e., gas burning stove and a good, tight insulated engine cover. I have graduated from a Coleman stove and stovepipe contraption to an Arctic Companion heater. Its definitely not as safe or convenient but it requires no electricity, only weighs about 5-10 lbs, and when packed up, its only about 24" long and 8" in diameter. It goes with me all winter as a bit of survival gear.

If the world really goes to hell, I can use it as a camp stove to cook with the top of the lid and burn avgas while waiting for rescue.

mvivion: "Now you're talking about combustion heat, not electric heat. That is a very different subject than what I was discussing "

Actually, in every instance, I was discussing and usually stated "forced air heat". Whether it's derived from combustion or electrons doesn't matter. Hot air (run thru an aircraft cowl) will heat an engine and ALL it's accessories (pumps, mags, carb/fuel system, and battery in many aircraft=especially important in true cold if you want to see an easy start) better than any permanently attached system with locallized heating elements. The engine will start more reliably and reach operating temperature more quickly and more evenly than any other method, and no alteration/modification of the aircraft is necessary. (The system also stays with you when you sell.)
Humidity (from a combustion heater) due to an aborted flight (rare) will be evaporated by the next warm-up period. That's an imagined problem, in my view.

Without going thru it all again, if one will simply re-visit this thread one will see that one's own special situation will lead to a good solution. There's lots of ways to skin the cat. My preference is to heat the entire engine compartment as opposed to heating only locallized areas of an engine (which always requires electricity to be handy, Mike, in which case an electric forced air heater will be just as useful as combustion types, and is still superior for the same reasons. Heck, you won't even have to worry about your condensation when you decide it's a no flying day.)

[quote="gahorn"] I bought a WalMart "Milk-House" 1500 watt heater for less than $20. I obtained some metal ducting from the local hardware/bldg-supply normally used to exhaust furnaces from a bldg., and pop-rivetted it onto the heater. I then bought six-feet of aluminum flexible ducting (8" diameter, similar to clothes-dryer hose but made of soft, flexible aluminum) and slip it onto the metal duct on the heater, route it up the cowling exhaust just below the firewall. This keeps the electric heater away from the area just below the airplane. (I don't like electric items sitting below gascolators.)
quote]

George, note above that the specific discussion was reference electric fan forced heaters. My point was that a 1500 watt electric fan forced heater will not warm the air passing through it enough to heat the engine at cold temperatures. try it sometime, in -10 degree weather.

Further, my comment was that both the Tanis and Reiff pre-heat systems FULLY pre heat an engine, including all accessories, and, if you have a rear mounted battery (as in a 180, etc) you can add a battery plate and warm the battery as well, so the thing will actually start the next day, and the next. Batteries in the 170 are on the firewall, so heating the engine compt works, but not true for all aircraft.

Again, my point was, and Tanis' web site suggests, that the installed systems DO in fact heat the entire engine, from within, ie: they heat the engine itself, which then radiates heat to the rest of the engine compartment, and warms it. I have often gone flying at temperatures well below zero, with one of these plugged in overnight, and EVERYTHING forward of the firewall is toasty warm.

Now, stuff the hose from a Northern Companion or a Red Dragon (I own and use both) in your cowling at -35 and you are not going to warm up the main bearings for a LONG, LONG time, cause those things don't generate a lot of heat, like a Herman does. And, since you are applying heat to the engine compartment, as opposed to the engine itself, it will take longer for that heat (inless its hotter than I want in my cowl) to reach the very core of your engine: the crankshaft, which is what you REALLY want heated.

In fact, at around -35 or -40, propane doesn't gasify any more, meaning that you have to apply some heat to the propane tank to get the gas to gas, so you can burn it in your Red Dragon.

I agree with you fully, that IF there is no electricity around, a forced air combustion heater is the way to go. The alternative is carrying a small generator around with you, and plugging in your Tanis system for a couple hours before flying. Problem with that is, the small generators won't start when they're cold, so they have to be pre-heated.

But, the original piece of equipment that you described is a 1500 watt electric fan forced heater, not a Herman Nelson. That was the focus of my comments, not large combustion heaters, and that should have been obvious.

Hey, heat em however you like but understand all the risks, and that, as you said up front, and I've agreed with in every post: MAKE DARN CERTAIN YOU HEAT THE WHOLE ENGINE, especially the core.

How's that?

Brain freeze? At a mere -38??? Nah, that takes at least -50. Or February,

Mike

Actually what I said originally was:

"I don't have the difficult wx conditions in Texas others have, so my solution may not be as elegant or effective as theirs especially in Arctic conditions, but....
I bought a WalMart "Milk-House" 1500 watt heater..."

That should have told you, Mike, that I make allowances for how much wattage for how much time is necessary in various conditions. That orginal msg post was merely a report on how a simple system will do the job in temperate climates such as the majority of folks have down here in the lower 48. It was not instructions that everyone must follow, it was an attempt to share info about a simple inexpensive solution that might be suitable for most people who visit these forums.
The rest of this thread revolved around basic theories of preheat, and I don't think anywhere else did I insist on a "WalMart Milk-House" heater being the cure-all. (Although 1500 watts, in conjunction with time and a blanket will heat up just about anything not sitting out in a blizzard.) What I thought was clear, but apparently not to you, was the significant difference between forced-air or hot-air systems as opposed to installed, electric, local-element type systems. Ok, you disagree. It's not necessary to take/make it personal.
How 'bout we quit this "he said-she said'? We can all read.

Where did all of the plumbers fire pots go up in Alaska?

Mike, I'm with George on this one. I use one of those milkhouse heaters too. However, I've extensively modified mine. It is now 480V/3 phase, & is now rated at about 20K watts. I've installed a bigger fan so it blows about 2,000 cfm thru a 24" round flex duct. Only a couple problems:
1) the 20 foot long welding cable I use as an extension cord weighs about 40 pounds.
2) the higher airflow of the pre-heater has bulged out the cowl on the airplane. In a way, that's good--if I decide to hang an O-360 on there, I won't need any cowl blisters.
3)it's kinda loud now-- the people that live near my airport have filed a restraining order against my using the preheater except between 7am & 9pm, this really reduces it's utility.
4) when I plug it in, it dims all the runway & taxiway lights. Also slows the airport beacon down to about half speed.
Other than that, it works great!
Now,George, you're being a bit prickley on this thread-- way too quick to take offense. In the past you've made some comments yourself that sometimes seem as though they're casting aspersions about others' qualifications, intelligence, or truthfulness. So chill out! If you dish it out, you gotta be able to take it.

Eric

No milk house heaters in neu Joyzee, we got walmarts, but no bovine isle

Eric,

A story, related to yours:

A friend saw me downtown several years ago, on a weekend, and asked if I was headed to the airport. I said I was. He asked if I could plug in his airplane, which was parked at an unnamed FBO. Said there was a brand new outlet right next to his plane. He asked that I make certain that the little fan forced heater inside his cowling actually started (sometimes when they sit overnight, cold soaked, the fan is frozen up, and they overheat, cause they have no fan), by listening for the fan to start.

I did all this. A few days later, I saw the same guy, and he accused me (with a big grin) of trying to burn his airplane down. Said he came out a couple hours after I plugged in his plane, and the fan on that heater was turning at what seemed like 20,000 rpm, and the engine was hotter than the hinges. The 110 volt heater was actually plugged into a 220 circuit.

I pleaded innocence, since 220 plugs are different than 110. Seems the owner of the FBO decided to rewire the outlets out front himself, rather than hire an electrician, and heaven knows, he didn't actually own a voltmeter.

I was impressed with the heater. It had run for at least two hours at double rated voltage without lighting anything on fire, and was still running like crazy. My friend retired that heater right away, though.

Engine pre-heat probably has more opinions than Carter has pills.

Use common sense, and watch whatever you use carefully.

Mike

Eric! You're a HOOT!!!
(and probably right. Hey, Mike, you got some of that arctic air up there you could fed-ex down here to give me a chill-pill?)
Speaking of electricians,...I paid my way thru the first year of college by working as an electrician's apprentice at a refinery. (Got the job thru my electrician-Dad's IBEW local.) Did it teach me to read? No. Only this year I decided to replace the cooling fan on my Miller Thunderbolt AC-DC welder. Coudn't find the correct part from Miller, so I adapted a large, 6"-square electronics cooling fan. It looks like a cooling fan for a huge computer,...I bought it from a surplus electronics store.... same place that sells new Ohmite rheostats for $1.
I bolted it inside the welder's outer case in the same location as the small fan it replaced, hooked it up, and plugged the welder in. Everything started spinnin' and hummin' and....smokin'!!! Fan sounded like a siren! Quickly unplugged the welder and examined things. Discovered that itty-bitty original fan was indirectly wired to 240 volts! (Assumptions can be wrong, eh?) Re-connected the computer fan to only one side of the phase circuit so it'd get only 120 volts and ....Voila! Hard to believe that little fan survived, but it did!) Things work fine now. All's well that ends well. From one pontificator to another: Sorry Mike if I was too hard on you.

Time to start preheating in Fairbanks!

Wind Calm (direction variable)
Visibility 1/2 mile(s)
Sky conditions obscured
Weather Freezing fog
Temperature -43 F (-42 C)
Pressure (altimeter) 30.61 in. Hg (1036 hPa)
ob PAFA 131553Z 00000KT 1/2SM R01L/3000V4500FT FZFG VV005 M42/ A3061 RMK AO2 SLP394 T1422

--------------------------------------------------------------------------------

Maximum and Minimum Temperatures
Maximum
Temperature
F (C) Minimum
Temperature
F (C)
-41.1 (-40.6) -45.0 (-42. In the 6 hours preceding Jan 13, 2005 - 06:53 AM EST / 2005.01.13 1153 UTC
-40.0 (-40.0) -47.0 (-43.9) In the 24 hours preceding Jan 13, 2005 - 03:53 AM EST / 2005.01.13 0853 UTC

--------------------------------------------------------------------------------

24 Hour Summary
Time
EST (UTC) Temperature
F (C) Dew Point
F (C) Pressure
Inches (hPa) Wind
MPH Weather
Latest 11 AM (16) Jan 13 -43 (-42) 30.61 (1036) Calm freezing fog
10 AM (15) Jan 13 -43 (-42) 30.61 (1036) Calm freezing fog
9 AM (14) Jan 13 -41 (-41) 30.63 (1037) Calm freezing fog
8 AM (13) Jan 13 -43 (-42) 30.63 (1037) Calm freezing fog
7 AM (12) Jan 13 -43 (-42) 30.63 (1037) Calm freezing fog
6 AM (11) Jan 13 -41 (-41) 30.63 (1037) NW 5 freezing fog
5 AM (10) Jan 13 -43 (-42) 30.63 (1037) Calm freezing fog
4 AM (9) Jan 13 -43 (-42) 30.63 (1037) Calm freezing fog
3 AM (8) Jan 13 -41 (-41) 30.62 (1036) Calm freezing fog
2 AM (7) Jan 13 -41 (-41) 30.62 (1036) Calm freezing fog
1 AM (6) Jan 13 -41 (-41) 30.61 (1036) WNW 5 freezing fog
Midnight (5) Jan 13 -43 (-42) 30.6 (1036) Calm freezing fog
11 PM (4) Jan 12 -43 (-42) 30.6 (1036) Calm freezing fog
10 PM (3) Jan 12 -43 (-42) 30.6 (1036) E 3 freezing fog
9 PM (2) Jan 12 -40 (-40) 30.6 (1036) Calm freezing fog
8 PM (1) Jan 12 -40 (-40) 30.6 (1036) NNW 3 freezing fog
7 PM (0) Jan 12 -40 (-40) 30.6 (1036) Calm freezing fog
6 PM (23) Jan 12 -40 (-40) 30.59 (1035) NNW 3 freezing fog
5 PM (22) Jan 12 -41 (-41) 30.59 (1035) Calm freezing fog
4 PM (21) Jan 12 -43 (-42) 30.57 (1035) Calm freezing fog
3 PM (20) Jan 12 -45 (-43) 30.57 (1035) WSW 3 freezing fog
2 PM (19) Jan 12 -45 (-43) 30.56 (1034) Calm freezing fog
1 PM (18) Jan 12 -47 (-44) 30.54 (1034) E 5 freezing fog
Oldest Noon (17) Jan 12 -43 (-42) 30.55 (1034) N 3 freezing fog

At -40F and below carbon steel becomes very brittle, broke a bunch of track pads on a cat near Big Delta one day while doing some loging. At -65F the diesel jelled and we quit. -59F in Northway this morning, plus 7F here this morning in the banna belt, guess winter is here.

Roesbery wrote:At -40F and below carbon steel becomes very brittle, broke a bunch of track pads on a cat near Big Delta one day while doing some loging. At -65F the diesel jelled and we quit. -59F in Northway this morning, plus 7F here this morning in the banna belt, guess winter is here.

Do you follow the High School BB games down there? My HS is there this weekend.