Pre-Heat

[Seth]

If you have a plug in pre-heater system, how many hours before you crank your engine do you plug it in and begin pre-heating?  Do you simply leave it it plugged in all winter, even when you're not flying?  Do you have a blanket on the cowl to keep the heat in?  Cowl plugs?  I ordered a pair of cowl plugs for the missile and intend to plug it inside the hanger.  When pre-heating, I plan to keep it plugged to keep the heat in.  I do not have a blanket at this time, but may figure something out soon if it is suggested.

I have heard some people say plug it in about 6 hours before the flight, with others saying leave it plugged in all the time.  I make sure to fly at least every two weeks, many times multiple times in one week, so sitting with a hot engine not turned on for over a month is not going to occur.

I've been told by keeping the pre-heater plugged in that the heated engine block over time will cause condensation toward the top of the case where the oil no longer is completely coating (gravity) and corrosion internally due to that condensation of water can begin.  If flown often though, the water will be boiled off and it won't matter.  Also, that way the engine metal parts won't slowly shrink and grow with the freezing temparatures.

Looking for what you do and your opinions.

Thanks!

-Seth

[John Pleisse]

Quote: Seth

If you have a plug in pre-heater system, how many hours before you crank your engine do you plug it in and begin pre-heating?  Do you simply leave it it plugged in all winter, even when you're not flying?  Do you have a blanket on the cowl to keep the heat in?  Cowl plugs?  I ordered a pair of cowl plugs for the missile and intend to plug it inside the hanger.  When pre-heating, I plan to keep it plugged to keep the heat in.  I do not have a blanket at this time, but may figure something out soon if it is suggested.

I have heard some people say plug it in about 6 hours before the flight, with others saying leave it plugged in all the time.  I make sure to fly at least every two weeks, many times multiple times in one week, so sitting with a hot engine not turned on for over a month is not going to occur.

I've been told by keeping the pre-heater plugged in that the heated engine block over time will cause condensation toward the top of the case where the oil no longer is completely coating (gravity) and corrosion internally due to that condensation of water can begin.  If flown often though, the water will be boiled off and it won't matter.  Also, that way the engine metal parts won't slowly shrink and grow with the freezing temparatures.

Looking for what you do and your opinions.

Thanks!

-Seth

[Shadrach]

Quote: Seth

I've been told by keeping the pre-heater plugged in that the heated engine block over time will cause condensation toward the top of the case where the oil no longer is completely coating (gravity) and corrosion internally due to that condensation of water can begin.  If flown often though, the water will be boiled off and it won't matter.  Also, that way the engine metal parts won't slowly shrink and grow with the freezing temparatures.

Looking for what you do and your opinions.

Thanks!

-Seth

[xftrplt]

 

Ross is correct. AC ran a test, reported in the Mar 07 issue.  They started at 40df and 60% rel. humidity and ran the heaters continuously for six days, graphing the temp., rel. humidity, and dew point.    The temps within the engine quickly stabilized at 120df, and the r/h dropped to <15%, while the temp - dew point spread widened to > 75df.  Hence, no condensation.

They recommended running a pre-heater continuously. 

 

[rocketman]

What I do is to burchase a little ceramic heater from Wal-Mart and put it on a stand below the cowl flaps. Put a good blanket over the engine and leave this little warmer run. Only costs a little in energy, and keeps the entire engine compartment warm. No fluctuations in temperature and maybe even better than evening coolings with day time warnings you get in the fall and spring.

[Seth]

I actually have a small heater simlar to what you have that I used on my old F Model to warm up the engine on cold days.  I would leave the cowl plugs in, and I had a dryer vent hose attached to the front of the heater that went directly into the cowl flaps.  I'd let it blow for a good half hour during my preflight, and then I'd crank.   I never did get a blanked, but I plan to now for the Missile.

I'll probably use that to warm up the cabin on really cold days now or blow under the instrument panel to try to warm up the electonics before I turn on the master.

I read some of the article from avaition consumer on leaving the block heater plugged in, and then went online to Reiff's website where some quotes from the article existed.  i didn't even check the Tannis website.  It looks like I'll leave it plugged in during the winter.  My Missile cowl plugs arrived today, so I'll swing by the airport tonight and see how they fit.  They look like they are correct, with the winking eye third plug as well.

Blanket wise, are most people just using and old sleeping bag and covering or removing the zipper?  A flannel blanket?  Old coforter/duvet cover?  I haven't looked into it, but is there a special material I should use or stay away from? 

I DO NOT want to attract mice to a nice hot warm insulated home during the winter.  Does anyone have a problem with Mice in the hanger near warm heated planes?

-Seth

 

 

[John Pleisse]

From Tanis:

Good Rules to Follow:

? Preheat the engine 4-5 hours before flight or overnight.

? The system can be left on continuously if the aircraft is flown

regularly (once a week or so).

? Use an insulated engine and prop cover to increase efficiency

of the preheat system.

Again...regardless, run your engine in flat out cruise for 2 hours at least once a week and there aren't any issues. That AC info is great news...think I'll leave mine plugged in all winter.

[Seth]

Thanks for the Tanis suggestions.

And I do fly often enough to keep the system on continuously.  Heck, about 25 hours on the Missile since pickup in early October.

I'll make some sort of cowl blanket, but probably not a propeller cover, even though the prop does act as a big heat drain - being inside the hanger however, with no wind, should make it less of an issue.

-Seth

[rocketman]

Hey Seth - Where did you get your cowl flaps for your Missle. I just bought my Rocket and need cowl flaps for it.

 

Ron

[Seth]

Cowl flaps were on the F model - the Missile has no cowl flaps. 

My missile has a plug in heater, so I'll use the electric one I had created for the F model to heat the cabin or have the fan duct under the footwells in order to warm up the avionics (I may never do that, but it's the plan).

Take care,

-Seth

[aviatoreb]

I think a lot depends on your climate - on how cold it gets at night and how warm it gets during the day - to each of your questions.  I have a full on real mcoy heating system since I live way north.  Look at KPTD on the map and you will see.  IN Georgia I would use a home made system. 

-Reiff has a nice chart describing how much of a rise in temp the oil and the cylinders will get based on each of their systems as a function of time plugged in.  I have their middle system which is oil heat and medium cylinder heat - the standard system as they call.  SO I can read right off the chart how much time it takes to rise the temp a certain number of degrees above ambiant.  So if I want my engine cylinders and oil say 50F for a safe start (or 40 or whatever), and the OAT is 10F then read off the chart how much time it takes with my system.   

-I am a big believer in plug in all the time in the winter.  First it makes sense to me that heat chases away moisture just like a heater in a gun case system.  Also the avconsumer agrees with data as some of you have cited.  It is important that the heater can raise the temps everywhere in your engine where there could possibly be water to well above freezing besides raising it well above ambiant.  You do not want any thaw refreeze cycles going on.  

-I live at the same latitude as Burlington VT in the Adirondacks.  In the coldest nights it has gone as low as -40F.  On Reiff's site they say the standard system as I have raises oil and cylinders about 80F above ambiant.  So above freezing still on the coldest nights.  In a hangar without wind mind you.  And with a cover to retain that heat.  The turbo xp system will raise it by 128F.  Well, I doubt the engine actually gets down to even 40F since while on the very coldest nights it may hit -40F I bet the heat inertia prevents it from getting down to 40F before the oat is already bringing it back up - the averaging effect of a mass with lots of thermal inertia.  On a more typical Jan night, it may go down to -15 or -5F at worst with maybe 5F by the morning time I would venture out.  So it is still nice and toasty inside my engine. I doubt my engine will ever go below 50F all winter.

-The poor human pilot (me) never bothers to drag the airplane out of the hangar if it is below say -10F.  My ears and fingers and toes get cold in the few minutes it takes to pull it out and preflight on such a day.  Airports always seem nippier and windier on such a day.  Not to mention the possibility of an off field landing is not so appealing on a day like that. Really colder days than that are not so common but they do happen.  BTW, I carry a sleeping bag and survival kit in the winter.  Even an evening in 20F could be unpleasant without.

-I use a proper tanis cover.  But wrong size....my last airplane was a Diamond DA40 and I have not sold that cover yet and gotten a new fitted one.  So my old tanis cover still fits but only on 2/3rds the nose.  It is nice as it wraps all the way around top and bottom and over the nose behind the prop.  I also have a cheap walmart sleeping back I drape over the cowl behind the tanis and it covers up a bit along the windshield.  I feel this keeps a tad of heat in the cabin by the instrument area.

- I use a tiny ceramic heater inside the cabin since your gyro instruments can also be damaged I have read by a frigid cold start.  Also to make it comfy.

-Preheating is very important as they say it causes major damage to do a frigid cold start w/o good heating.

-There is a thimble full of water in your crank case following shutdown that comes just from the fuel burning process chemistry from combining H from the hydrocarbons with O2.  It burns off if your oil is above 180F but in the final minute(s) say short final of flight and in taxi, I believe your oil cools significantly and it is making water. Isn't that right?  This is just what I believe.  I have on occasion checked my oil at shutdown and found a tiny bit of water at the top of the dip stick screw area.

-So on recommendation of Reiff and several other sources, I leave my dip stick unscrewed ever so slightly when I have continuous heat applied.  If I return to the engine even a few hours later it is completely dry.

-I believe on physics arguments grounds, but have no data for, that since heat rises and it is much hotter in my engine than outside, that it will draw air from below and pull it up through the top including through the now open topped crankcase and pull through dried air.  Like a tabaco smoke house.  This is my wives tail I operate under and I believe it will chase moisture and corrosion.  YES, YES I know this a point of debate.  I LOP too.  {:-)

-So heating has two benefits.   Safe cold day starts. and continuous heating I believe chases corrosion.  

-My engine is 45k to overhaul so not investing in a preheater appropriate to the climate I live would be penny wise dolar foolish.  Again I would have a different standard in Georgia.

-I also use camguard and also I fly roughly at least once a week in the winter often two, but every winter there seems to be at least one, maybe two spells of a two or three weeks where all the days I am not working are always taken by mother nature's surprise blizzards.

-Despite all my trouble and theories for preventing corosion etc....well my airplane did sit for 2 years several years before I purchased it, when it had 450 hours, then the next owner flew it between hours 450 and 750 in two years.  So I am probably already screwed.  It has 850 hours now since I got it in April.  Seems to be fine for now and what else can I do but baby it rolling forward.

[xftrplt]

Thankfully, the following defies my imagination:

Quote Aviatoreb:  

This is my wives tail I operate under

[aviatoreb]

Quote: xftrplt

Thankfully, the following defies my imagination:

Quote Aviatoreb: