Preheating temp?

What temperature do you consider preheating the plane?

  • < 40 * F

    Votes: 28 57.1%

  • < 32 * F

    Votes: 16 32.7%

  • < 20 * F

    Votes: 5 10.2%

  • < 0 * F

    Votes: 0 0.0%
  • Total voters
    49
  • Poll closed .
Rob Schaffer

Rob Schaffer

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CLR2TKF
I'm interested to know what temperature you decide it is cold enough to preheat, or request preheat if you are a renter? AOPA Flight Training had an article about a school in the North that flies when it's way below zero!, which got me thinking about this.

If you rent, what procedures may be in place at your FBO regarding preheat of the aircraft?

Currently, I know my FBO pulls the airplane in if you are the first to rent in the morning and there is a chance of Frost. They clean the plane and prepare it for you, but I'm not sure if they preheat or start the plane in the morning before I pick up the keys. I'll have to check with them this week. With the winter setting in early here in PA, I'm interested to know your thoughts so I can adjust accordingly for my pickup times and planning.

Consider the temps constant overnight for 10-12 hrs or multiple days where it is cold.
 
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When the temp is in the 30s or below, I preheat the airplane. I find if makes for much easier starting. I pay careful attention to the control surfaces being free and correct too, as they can get stiff in the cold.
 
Oh Boy - this is like the high wing/low wing debate! Guess it's just personal preference, but I'll go with the <40F number. Seems as though starting is easier, less load on the battery and the oil temp comes up faster. Also a lot more comfortable pre-flighting a warm engine. That being said, I've started it up at considerable lower temps with no heat, without much issue.

Using a flexible hose to help melt the frost off the wings is a nice side benefit of having a flamethrower!

Gary
 
I consider it below 40F, strongly consider it below 32F, and don't fly without it below 20F.
 
From Lycoming's Service Instruction No. 1505


The use of pre-heat will facilitate starting during cold weather, and is required when the engine has been allowed to drop to temperatures below +10°F/-12°C (+20°F/-6°C for –76 series engine models).​
 
For some info from Lycoming on cold weather operations, go to page 14 of this PDF (48 of the scanned in document):

http://www.lycoming.com/support/tips-advice/key-reprints/pdfs/Key%20Operations.pdf

And the full content of Lycoming Service Instruction 1505 that Steve references:

http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1505.pdf

For the Mooney, we make a point of trying to get it plugged in for a preheat any time the temp is below 40F or so. This is for longevity purposes. Below 20F I'd say is where it becomes a requirement. We recently got a timer for the Tanis heaters, so that way we can set it to start heating at the appropriate time before our flight. Very convenient if your flight is first thing in the morning. :)
 
I won't pull the starter under 40 degrees F. My Engine was built in 1946 - majored in the 1990s - and I want to keep it "comfortable" as long as I can.

Here in northeastern Maryland we are getting an early taste of winter. However, the normal daytime temperature right now should be 50 - and in January, the average is actually 41F. So there may be a lot of days when I will not fly - there will also be a lot of days when it is comfortable to fly (not to mention the pre-flight :D).
 
What about gyros? At what temp (if any) do we start subjecting them to accelerated wear?


Trapper John
 
Since I own a preheater and my 140 starts waaaay better when preheated, I preheat
anytime below 40 deg F. It's not much an issue for me now that I'm in a heated
hangar. :)

The last FBO I rented from preheated the airplanes before the first scheduled
flight of the day. They are an expensive FBO but it was a good outfit.
 
Rob Schaffer said:
...Currently, I know my FBO pulls the airplane in if you are the first to rent in the morning and there is a chance of Frost. They clean the plane and prepare it for you, but I'm not sure if they preheat or start the plane in the morning before I pick up the keys. I'll have to check with them this week.
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Rob, Wings will preheat the rentals for you. Just ask the linecrew. They'll also spray deicer on they airplane if need be.

Lee
 
We will plug the RV in if temps are below 40*F and we know we'll be flying. We have no gyros, so no problem there. I try my best to wait for oil temps to get above 80*F or so before takeoff.

I'm not sure what the FBO does. I still do a medium power idle on the ground to warm up the oil if the engine feels cold, though. Usually, if I'm renting, I'm flying to a point that is much warmer than here, so I don't have to worry about pre-heat away from home. :)
 
Thanks guys. Lee, thanks for the info on Wings, I was going to call this week to double check. While I'm down at St. Michaels this weekend, temps are forcast still in the low 30's for the highs right now, so I may request preheat from the FBO there as we begin our drive back to the airport since the plane may be sitting on the ramp 5-6 hrs while we are in St. Michaels.
 
First, I ignore whatever C/L have to say about this. They're usually wrong.

Second, my friend in the automotive industry tells me that their tests have shown that anything below 70 degrees will damage cylinders to some extent. So, if I can't put the plane in a hangar, I'll just plug in both engines the day before. Takes one minute and an extension cord ;)
 
sba55 said:
Second, my friend in the automotive industry tells me that their tests have shown that anything below 70 degrees will damage cylinders to some extent. So, if I can't put the plane in a hangar, I'll just plug in both engines the day before. Takes one minute and an extension cord ;)
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Doesn't running the engine at all "damage cylinders to some extent?" That why there's a TBO on the engine. My personal observation, having owned/flown several different Lycoming and Continental HP engines for well over a thousand hours of time on them, that changing the oil often and flying it often is the best thing you can do for an engine. This thing about cold weather wear and metals expanding and contracting at different rates might have been true back in the day but with modern multi-viscosity oils and modern engines, it seems like an over-hyped topic. I preheat if that's what it takes to make it crank at all and then go flying regardless of the temp here in the continental US. The Continental 550 in my Columbia is at 600 hours with no sign of wear and original jugs. The Lycoming AEIO540 in the Pitts is at 300 hours. Never anything in the screen and the compressions are spot on to what they were when it settled in at 25 hours new.
 
PittsDriver said:
Doesn't running the engine at all "damage cylinders to some extent?" That why there's a TBO on the engine. My personal observation, having owned/flown several different Lycoming and Continental HP engines for well over a thousand hours of time on them, that changing the oil often and flying it often is the best thing you can do for an engine.
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You're absolutely right. I don't know why they picked 70 as the cutoff - probably because the additional wear caused by the temperature was small. In any case, like you said, the engine undergoes stresses during every start.

As for what TBO is for - personally, I consider that to be one of the most useless numbers in aviation. TBO means nothing, except that it's the lowest common denominator for the lifetime of a specific type of engine. Of course, those lifetime averages are affected by many, many factors - where the engine is usually operated, how it's operated, etc. I was TBO+500 on my old plane and the engine was doing really well. If I hadn't sold it, I'd probably be at TBO+700 now, with no intention of replacing it.

PittsDriver said:
This thing about cold weather wear and metals expanding and contracting at different rates might have been true back in the day but with modern multi-viscosity oils and modern engines, it seems like an over-hyped topic. I preheat if that's what it takes to make it crank at all and then go flying regardless of the temp here in the continental US. The Continental 550 in my Columbia is at 600 hours with no sign of wear and original jugs. The Lycoming AEIO540 in the Pitts is at 300 hours. Never anything in the screen and the compressions are spot on to what they were when it settled in at 25 hours new.
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It's still very much a problem. For most car engines, they guess that one start at 40 degrees is equivalent to one start at 80 degrees.

It's a small piece of the puzzle. There's other things that can severely limit the life of an engine. Cold starts are just one of them.

-Felix
 
Thsi is gonna be funny. The responses are going to be based on what you as a person consider a cold and and unusual day. Thus, Lance, Tony, Jesse, Scott and I look at single digits, and out on the left coast by Felix they think that 50 degrees F is thermal underwear time. :rolleyes:

Again. FifTY is not cold. FifTEEN is cold.
 
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mikea said:
Thsi is gonan be funny. The respnses are goign to be based on what you as a person considert cold and and unusual day. Thus, Lance, Tony, Jesse, Scott and I look at single digits, and out on the left coast by Felix they think that 50 degrees F is thermal underwear time. :rolleyes:

Again. FifTY is not cold. FifTEEN is cold.
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Remember, I live in an area that has desert like temps. Hot during the day, cold at night.

Anyways, I'm just pointing out that pre-heat isn't only beneficial at really low temps. 50 isn't cold, but pre-heat will still be better for the engine.

Felix
 
Around here the heaters come out the few days it drops below 70.
 
my fbo plugs em in once it gets below 40 or so. thats how i prefer it too. makes it really easy to get things running. plus, if Ted says to do it, i believe him.
 
tonycondon said:
plus, if Ted says to do it, i believe him.
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If Ted says to jump off the bridge, would you do it? (said in the voice of my mother) :rofl:

And my FBO mandates preheating below 20* and doesn't allow flying below 0*, IIRC.
 
IIRC our club rules are plugin below 40, preheat below 20, no T&G's below 0.
 
gprellwitz said:
If Ted says to jump off the bridge, would you do it? (said in the voice of my mother) :rofl:
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Ahh, but I wouldn't say to jump off a bridge! ;)
 
Our club requires it anytime it's been below 40 for the previous 8 hours.
Like others have said provides some comfort margin and longevity of the engine.
 
Hi,

The iMooney's Lycoming reference is excellent. There is a great deal of information not only on pre-heating but also on cold weather ops in general (fuel mixture, checking carb heat religiously).

I also agree with the multi-vis oil comments and longevity. I am a partner in a Mooney club but also fly some of our FBO's planes and they plug in (Tanis) or require a pre-heat if you are away, below 32 F and do not dispatch A/C below zero F (unless prior arrangements are made).

The Tanis website it quite good for info on how a good Tanis heating system works. http://www.tanisaircraft.com/whatisintanis.html

Our Mooney is plugged in any time after October (<40 F). (Wisconsin)

I am particulary careful on decents and try to carry some power, watch CHT and try not to sub-cool the jugs. I think it is a fact that this severely wears the cylinders but I am mostly trying to avoid an engine failure while up-above!

Keep the shiny side up!
 
Well, I was spoiled by the FBO that morning. They pulled all the planes that were flying first (8am) into the large HEATED maintenance hangar for the night. My wife and I were able to preflight completely in the hangar out of the cold morning air. The FBO said I should be fine for the day, since it was going to about 40* down at St. Michaels, just put the cowl plugs in right when I land.

If I owned a plane or was partnered' up in one, I'm sure I would have preheated that morning, as it was a cold, damp night. Thanks for the replies,... have a good New Year!

You can read about our flight and see photos HERE
 
I try to use the crankcase heater if it's below 40. We have a timer too, so we can have it in to turn on at 2 am before an early morning flight. Fairly convenient since we now live a mile from the hangar. ;)
 
Since I like engines (when they work), starting is not the only consideration for pre-heating.

Think about the viscosity of oil in freezing temps and consider how long before that glue liquifies and starts freely circulating and protecting all the metal-to-metal contacts.

Thus whenever it's under 40 (though not an absolute number -- if the a/c is in the hangar and the ambient temp in there is warmer than outside, the engine's been run recently, etc), I look for the preheater.

And the preheater stays on for at least 45 minutes (It doesn't matter how the cowling feels -- it's not starting) to fully warm the engine block.

When you or a few in your club are paying, things like premature engine wear really get your attention.
 
One friend of mine had an engine eat its tappets, which he attributed to a lack of engine pre-heating. The engine was not new, but needed to be replaced as a result. They are now very careful about making sure to pre-heat the engines. Not trying to scare anyone as that is the only person I personally know who has had that happen, but failure to properly pre-heat your engine can cause failures. Dan's absolutely right - it becomes really noticable if you're the one who is affected by it. Regardless of that, I can't bring myself to do stupidly damaging things to engines. Doubly so since I depend on them to not die on me.

A practice I saw that I found particularly interesting (and have since been told is not uncommon, but it was unknown to me so it might be unknown to others) I observed in Ames, when Tony tucked in the engines on the 421 with sleeping bags. It covered the nacelles and plugged the cowl holes, thus keeping all that nice expensive heat in. Seems like a good idea both to keep the engine warmer (especially in bitterly cold temperatures) and help heat it up faster. I like the idea enough that when I get a plane I'll do it myself. :)
 
Ted DuPuis said:
A practice I saw that I found particularly interesting (and have since been told is not uncommon, but it was unknown to me so it might be unknown to others) I observed in Ames, when Tony tucked in the engines on the 421 with sleeping bags. It covered the nacelles and plugged the cowl holes, thus keeping all that nice expensive heat in. Seems like a good idea both to keep the engine warmer (especially in bitterly cold temperatures) and help heat it up faster. I like the idea enough that when I get a plane I'll do it myself. :)
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I have cowl plugs but I also wrap the cowl with one of those moving blankets and it also covers those giant heat sinks known as propellers.

That helps hold in the heat from my cylinder heaters and oil pan heater which goes on whenever the temp drops below 40F thanks to a thermo cube that I have on the extension cord.
 
OK, so the hangar is unheated. But that still keeps frost and such off the metal. Each year (when I have a job) I try to do something to improve the airplane. 3 years ago it was a Reiff oil pan heater and a large sleeping bag over the cowl. 2 years ago I "inherited" a bunch of stuff from a friend who sold the 172 - that included prop covers and a cowl cover. Fit better on my cherokee than on the 172 that spent a number of years in Alaska!

When traveling, even just for lunch, if the weather's going to be cold, the cowl cover comes along stuffed in the back and thrown over the cowl when we park. Altho the heater wasn't plugged in last week (sunny, bright weather but temps at 5F) for the 2 hours of lunch, started right up.

A number of folks around the airport, quite impressed with the results of my oil pan heater, have also installed this this past summer. Makes winter/cold flying much easier.

I should also point out that when it's really cold (below 0F) forget the airplane, it's too cold for me to fly!
 
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Ted DuPuis said:
A practice I saw that I found particularly interesting (and have since been told is not uncommon, but it was unknown to me so it might be unknown to others) I observed in Ames, when Tony tucked in the engines on the 421 with sleeping bags. It covered the nacelles and plugged the cowl holes, thus keeping all that nice expensive heat in. Seems like a good idea both to keep the engine warmer (especially in bitterly cold temperatures) and help heat it up faster. I like the idea enough that when I get a plane I'll do it myself. :)
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1172848073161-1060509567.gif
 
MooneyRangerGuy said:
I am particulary careful on decents and try to carry some power, watch CHT and try not to sub-cool the jugs. I think it is a fact that this severely wears the cylinders but I am mostly trying to avoid an engine failure while up-above!
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It's not a fact, and it's also not true that you can effect CHT changes that are rapid enough to affect engine longevity with just power in cruise or descent for our engines.

You can, however, effect these rapid temperature changes by shoving the mixture full forward after having cooled the fuel at higher altitudes for a while. This is where this whole idea came from.

-Felix
 
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alaskaflyer said:
IMG_0472.jpg
IMG_0473.jpg


As far as when to preheat...

IMG_0470.jpg
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How the heck do you guys keep the engines warm enough when you are flying? My flight back from FL where I hit -20C temps really stressed the low end of the oil temp gauge. When I flew the Cessna we had little covers that went on the cowl to close up the openings. but the Piper has nothing like that. Do you guys just tape up the oil cooler and close the cowl inlets with something?
 
smigaldi said:
How the heck do you guys keep the engines warm enough when you are flying? My flight back from FL where I hit -20C temps really stressed the low end of the oil temp gauge. When I flew the Cessna we had little covers that went on the cowl to close up the openings. but the Piper has nothing like that. Do you guys just tape up the oil cooler and close the cowl inlets with something?
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Yep. 100 mile an hour tape :p completely covering the oil cooler and partially covering the cowl openings in a pattern that mimics the original Cessna OEM cold weather kit.

Problem is you need to understand the designed air flow in your pressure cowling before you start monkeying around with duct tape, otherwise you will have very uneven cylinder cooling.
 
I had an IR lesson flight tonight, and the 160hp Lycoming in a C-172R started right up, to my surprise. Here's the METAR at start-up:

KUES 300145Z 28015G25KT 10SM SKC M01/M09 A3010

I was impressed! It was flown in the early afternoon, but unused for 5-6 hours. The previous renters didn't plug it in, and didn't put the blanket on the cowling. Upon return tonight, though, we plugged it in and tucked it in.
 
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