bbrrrrrr-it's cold up here.

[witrakw]

winter has arrived in Duluth, MN. Already below 0 Fahr. Engine heater and cowling blanket work fine in conjunction with jerry rigged cockpit heater. The cockpit heater and engine heater are on a "beeper box" that activates the electrical circuit from afar by paging a belt type beeper attached to the beeper box.

question- cht's. I keep reading that one is supposed tokeep cht's above 300 and below 400. No problem in this weather keeping them below 400 even on climbout and I love this 2000 fps climb rate. CHTs usually don't even reach 370. The problem is on the other end of the temp scale. At cruise(75%) they are barely in the low 300's and then if you LOP they drop into the high 200's. Cowl flaps are closed and oil cooler is largely duct taped over. I hate to run it at 50 ROP or peak egt because of what Deakin says about the compression cycle(in short, avoid 50 ROP to considerably LOP).

High 200's bad for the engine? Short of a really"cold" engine I would think that engines would like to run cooler than hotter but is this "too cold"?

Sure am enjoying this plane and keep getting a lot of OOH's and AAH's.

[Todd Peterson]

If you're in a really cold part of the country keeping your engine temperatures up can be a problem. I don't really view CHT's in the high 200's or low 300's as a problem. The factory allows you to take off with CHT's as low as 200F so I don't see anything above that as much of a problem. On top of that there isn't a lot you can do about the coolest temps if the OAT's are in the 30's and up. When the OAT's drop into the 20's and below there is a winterization kit from Cessna that you can install. It reduces the size of the cowl air inlets to keep some of the cold air out. There is also a restrictor plate that goes over the air filter. When flying in the really cold temps I use this kit and it works very well. As the engine temps are higher the engine runs much smoother.

Winter flying also makes a good case for keeping the mixture lean on descent to stabilize the CHT's. Like you said it is also important to tape over part of the oil cooler. Keeping the oil temps up in the 180F range this time of year can be a problem. As the oil temp probe gives you the oils coolest temperature I usually try to keep the temp around 150F. Depending upon the temperatures this may involve taping over half to two thirds the oil cooler. Without keeping you oil temp up there in the normal range you're just not going to get all the condensation of of the engine.

[Mike Sullivan]

Man do I love sunny Southern Calif. where the sun spends the winter. It was 80 degrees here this afternoon and I was running around in a T-shirt. Perfect flying weather for as far as the eye could see.

Mike

[witrakw]

Hey, it's not all that bad flying up here in the north country. At least in the summer time my plane's payload increases because of all the bloodsucking, flying vermin up here that decreases the average pilot's/passenger's weight by at least 5 lbs each!

The other plus in the winter is that at -30F there is not a lot of taxiway traffic to contend with.

Thanks Todd for the info. My local mechanic also suggested that he insulate the oil breather line so it doesn't freeze and blow out the front engine seal. Since blowing out the front seal doesn't sound like a desirable event, it sounded like a good idea, and unless you think otherwise, I will have him do that( the other thing he said he could do would be just to put a smalll hole on top of the oil breather line as an escape like valve in case the line distally got frozen.

That air restrictor plate for the air intake---doesn't that decrease MP and secondarily HSP or does the increased density of the cold air compensate???

As a "never owned a plane before" guy, it is interesting to learn all about this stuff.

thanks bill