Winter: Preheating before flight.

[allen]

Well winter is officially here and this is my first winter as an owner. I know several pilots like to ground their birds in the winter and use that time to perform upgrades. My plane lives on the ramp at the moment and I would really like to keep flying. Virginia winters are usually mild and this winter is forcast to be warmer than usual.   All that said it still gets cold! This morning it was 26F according to my outside digital thermometer.

My question: at what temperature do I need to start preheating the motor? Also, how do I do that since I’m on the ramp? What temperature do I need the motor to be at before I can safely turn it over?

[mikeydidit98]

I have an old torpedo heater that I converted for this use.  I attach a large dia. tin air duct pipe with a 45 joint at mid span (approx 8ft total span).  I put one end at the heater and the other at the air inlet under the belly and let her go for 15 min or so.

Make sure you are not at too high temp at the exhaust end of the duct pipe, or you will melt your baby.

[Joe Person]

See Lycoming Service Instruction SI-1505 as a start.  

FWIW, both Lycoming and Continental have several of the more popular Service Bulletins, Service Letters/Service Instructions on their respective websites.  All operators of these engines should spend some time reviewing and researching such data so as to understand more about their engines, as well as to determine maintenance or repair practices that could be beneficial.

[allen]

Thanks for the redirect. I have Lycoming’s website saved and I spend a good deal of time on it these days. That said I cannot find anything that is black and white about temperatures.

At what temperature do I want to consider pre-heating the motor before a flight?

Too what temperature do I want to pre-heat?

Also, what damage really occurs from not pre-heating? We all drive cars that do not get preheated and they seem to do fine. They also have multiple metals in them as well and seem to weather the abuse just fine. This morning the Jeep’s 5.9l fired no problem in the 37 degree morning air.

 (When I lived in Alberta as a kid this was not the case. Everything had electric preheaters on them, but it was also 40 below regularly.)

[Joe Person]

From SI-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)."

If you run Multi-Vis oil, you are better off w/r/t cold weather starting.

Lycoming SI-1014, Rev M, gives recommended oils.

With my O-200 VariEze, I run straight weight oil, and I preheat as the engine temperature (when cold) gets below around 40 Deg. F.  I use the carb temperature gauge to make the engine temperature determination.

I'd talk to Ken Miller for excellent information on engine operations - Ken is an engine Guru, and deals with cold weather ops (he's based on the East end of Long Island, NY).

[Snappy]

I use the 50 degree rule.  Under 50 gets heat.  I also have used an "EZ Heat" pad attached to the oil sump on my Lyc Long Ez for several years now with good results and a heavy duty lamp type timer to turn on the heater 3 hours prior to start up.  My oil is just under 100F even in single digit temps which helps in starting and getting warm oil into the cylinders.  After startup, warm up time is reduced considerably.  I won't take off until the oil temp reaches 110F and cylinder heads are 250+.  I think a lot of prop seals have been blown taking off with a cold engine.

I have used an extension cord on the ramp during freezing temps with good success.

my 2 cents.....

[Drew]

To add to Snappy's comments....  The prop seal is the seal that goes around the shaft at the back of the engine (side where the prop is).  Many engines don't have a retainer to hold this seal in place---for the most part, only glue and friction hold it in place.  There have been several articles either in CSA or the CPs that tell how to build a retainer.  However, the point is----if you blow out the prop seal, you will lose lots of your oil.

Go to this page to look at some EZ heating that you can do:

http://www.berkut13.com/berkut50.htm#Heating

[allen]

After digging around Lycoming website I found a technical FAQ that said 20 degrees was the magic number so I suspect I’ll set a personal limit a bit higher.

Yesterday I flew to Tazewell to visit the in-laws. At Roanoke the temp was close to 60 degree for takeoff so all was well. These planes love the cooler temps that’s for sure. I was at pattern altitude before I reached the end of the runway.

The flight home was done at night. I had flight following for a little safety margin and the entire trip was only .6 hours. However, I have to admit that I do not like flying these things at night. Don’t get me wrong, I have faith in the plane, but like Snappy wrote in the other thread, some things cannot be planned for.

Prior to takeoff the temp had fallen to 39 degrees. She started after 2 blades and ran strong. I sat for a bit to warm everything up. The CHT’s came up quickly and the oil took a bit. After the E.I. said the oil was up around 100 or so I back taxied and did my run-up.

After reading what you had to say Drew I think I’m going to call LC’s and see if I can pull her in the hanger and pull the cowling off. Now I’m worried.
 :?