Warm up question?

[Buckaroo]

I’m in Montana and it’s damn cold. Today with temps in the low teens all I could get for temps at run up was 105 degrees. 122 degrees was a long way away. I’ve got most my cooler aluminum taped with a tiny bit still exposed. 

Question? Should I be concerned taking off with temps in the 105 area? 

Thanks everyone! 

[Ed Cesnalis]

how much tape do you have on the radiator?   Mornings have been cold here down to -22F.   I do use a little more RPM sometimes.

[Mike Koerner]

Hi Buckaroo,

I don't think you should fly if you can't get the oil temperature up. My handbook lists 120 F as the minimum oil temperature.

I think running the engine at high rpm at lower oil temperatures will cause the oil filter bypass to open, which means you're not filtering the oil anymore. That's going to increase wear on the engine. Also, the plugs are more likely to foul when the engine is cold.

I'm very surprised that you are not getting higher oil temperatures with the radiator blocked. Is this at 2500 rpm? My handbook says to keep the rpm below 2000 for the first 2 minutes but after that I can run it up to 2500 rpm until it gets to 124 F,  at which point I can go to full throttle.

As Ed suggests, you might try pushing the rpm a bit higher as you get close to 124 F. It makes sense that progressively higher rpms might be acceptable as the oil viscosity is getting progressively lower.

I took off from Ohio last week with the plane left out overnight and the OAT below 0F at takeoff. The battery was a problem to be sure, but with 3 vertical strips of 2" wide tape down the radiator I was able to get the oil temp up into the 140F range. With a negative 2000-foot density altitude the aircraft performance was wonderful, but I did have to be careful to maintain power during descents.

Mike Koerner

[Buckaroo]

Thanks for the response guys! I’ve got so much tape on there I’m kinda concerned it will get hot away from a field. I do notice that a little higher rpm’s seem to cool her more. I always sit away from the wind while waiting. I’m thinking seriously about blocking the grill totally until warm shutting her down pulling the blockage and proceeding. 

[Ed Cesnalis]

I have experience with this.  If you have too much tape you will be overheating before you reach pattern.  You can simply fly the pattern, land and take a portion off.  You don't have to sweat it creeping up on you because it happens right now.

[DocRon]

When I lived in northern Minnesota I found an easy way to regulate the temperature and not fool around with tape.  Get some two inch thick flexible foam rubber and cut two pieces each being the approximate shape of your air inlet but slightly larger and only one third as wide as the inlet.  From 30 degrees to about 5 degrees place one piece of the foam rubber in the center of the inlet.  Below five degrees place two pieces of the foam rubber on either side of the inlet opening, leaving the center portion free for air to come in.  This worked very well and I was able to get the temperature up while flying at -20 (only once, way too cold to do a second time.)  Good luck!

[Buckaroo]

Good idea and great tip! Thanks! Today we’re finally getting into the 30’s so the worse is over thank god!