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Safe oil temp for take off ? (O-360)
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David-aviator
Well Known Member
Piper says in the 180 "G" hand book regarding warm-up and ground check,
"Check both the oil temperature and pressure. The temperature may be low for some time if the engine is being run for the first time of the day, but as long as the pressure is within limits the engine is ready for take-off."
The Lycoming Operators Manual (O360) simply says,
"Engine is warm enough for take-off when the throttle can be opened without the engine faltering." No mention of OT at all.
I feel ok about taking off when the OT gage comes off the cold peg.
"Check both the oil temperature and pressure. The temperature may be low for some time if the engine is being run for the first time of the day, but as long as the pressure is within limits the engine is ready for take-off."
The Lycoming Operators Manual (O360) simply says,
"Engine is warm enough for take-off when the throttle can be opened without the engine faltering." No mention of OT at all.
I feel ok about taking off when the OT gage comes off the cold peg.
Brantel
Well Known Member
90° for run-up and 100° for takeoff for me. I have seen what that stuff looks like when it is cold and there is no way I would subject my engine to that torture.
Most of the time when it is cold around here I use the sump heater. Stays on most of the winter. I plug the inlets with a couple T shirts and cover the cowl up with a doubled over sleeping bag.
I can go to the hangar when it is 20° and pull the inlet plugs and the entire area inside the cowl is nice and toasty warm. Oil temp is usually 85-90° on startup.
I think the key to keeping condensation out of your engine when using a sump heater is to keep the "entire engine" warm all the time and to fly frequently. The blanket and inlet plugs allow me to do this in this climate.
Most of the time when it is cold around here I use the sump heater. Stays on most of the winter. I plug the inlets with a couple T shirts and cover the cowl up with a doubled over sleeping bag.
I can go to the hangar when it is 20° and pull the inlet plugs and the entire area inside the cowl is nice and toasty warm. Oil temp is usually 85-90° on startup.
I think the key to keeping condensation out of your engine when using a sump heater is to keep the "entire engine" warm all the time and to fly frequently. The blanket and inlet plugs allow me to do this in this climate.
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Oil, CHT, smooth
Following the guidance from superior and general literature, I expect:
75 degrees oil temp,
CHT of 150+ (some say 125),
oil pressure in the green,
and smooth acceleration to run up RPM.
In my cold weather experience, by the time I get 75 degree oil, the other items are satisfied.
Following the guidance from superior and general literature, I expect:
75 degrees oil temp,
CHT of 150+ (some say 125),
oil pressure in the green,
and smooth acceleration to run up RPM.
In my cold weather experience, by the time I get 75 degree oil, the other items are satisfied.
Lots of different opinions can be expressed, but I agree with David's study of the manufacturer's data. I am generally comfortable at 75 degrees, as I know that the gauge is well off the peg and I can trust that it hasn't just flipped a bit.
Paul
Paul
JonJay
Well Known Member
Lycoming recommends not idling below 1000 rpms on start up. In fact, they dont recommend continuous idling below 1000 rpms at anytime.
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JonJay
Well Known Member
I will follow David and Paul here. Keep in mind, Lycoming does not even consider using preheat until 10deg F or below so what does that tell you?
Common sense, oil flows better when warm, so one could assume less wear. However, they invented multigrade oils for a very good reason. That stuff flows really well cold.
Common sense, oil flows better when warm, so one could assume less wear. However, they invented multigrade oils for a very good reason. That stuff flows really well cold.
Oil Temp
Aerosport IO-360. I'll do run up at 90 degrees. Then wait until 95 to take the runway. Haven't done research or found any hard numbers, but it just seems reasonable. The plane is hangered at Inyokern in the Mojave desert so I'm not dealing with real cold starts.
Aerosport IO-360. I'll do run up at 90 degrees. Then wait until 95 to take the runway. Haven't done research or found any hard numbers, but it just seems reasonable. The plane is hangered at Inyokern in the Mojave desert so I'm not dealing with real cold starts.
BigglesRV7A
Well Known Member
Straight from the Guru....110 deg F recommended
See this link from Mahlon Russell Some worth while reading including min CHT's and oil temp prior to full power.
http://www.mattituck.com/topframe.html
Non turbo 110 degs F prior to full power.
Greg
See this link from Mahlon Russell Some worth while reading including min CHT's and oil temp prior to full power.
http://www.mattituck.com/topframe.html
Non turbo 110 degs F prior to full power.
Greg
db8
Well Known Member
Difference of opinion?
Looks like a difference of opinion here. Have reviewed the previous post link and here is what it says (concerning some earlier comments on taxi RPMs):
Keep RPM To A Minimum At Start Up
After engine start up we should run the engine at the slowest RPM that the engine will continue to run at. If it will stay running at 700 RPM then that is the RPM we should be running at not 1400 RPM. Allowing the engine to run at a high RPM right after start with out letting it warm up can cause premature wear to many internal engine surfaces that are splash lubricated. Some of these splash lubricated components, most notably the camshaft and tappets, are especially susceptible to damage right after start with cold oil and high RPM operation. Keeping the RPM to a minimum will limit the amount of interaction of these components before enough oil has splashed around inside the engine to provide sufficient splash lubrication.
I don't know whose right or whose wrong, nor do I want to highjack this slightly different topic (taxi rpm vs safe oil temp at takeoff), but I sure would like to know the answer to the RPM max, min or whatever taxi when cold. Anybody really know? I can kinda see both points of view.Thanks. Dave
Looks like a difference of opinion here. Have reviewed the previous post link and here is what it says (concerning some earlier comments on taxi RPMs):
Keep RPM To A Minimum At Start Up
After engine start up we should run the engine at the slowest RPM that the engine will continue to run at. If it will stay running at 700 RPM then that is the RPM we should be running at not 1400 RPM. Allowing the engine to run at a high RPM right after start with out letting it warm up can cause premature wear to many internal engine surfaces that are splash lubricated. Some of these splash lubricated components, most notably the camshaft and tappets, are especially susceptible to damage right after start with cold oil and high RPM operation. Keeping the RPM to a minimum will limit the amount of interaction of these components before enough oil has splashed around inside the engine to provide sufficient splash lubrication.
I don't know whose right or whose wrong, nor do I want to highjack this slightly different topic (taxi rpm vs safe oil temp at takeoff), but I sure would like to know the answer to the RPM max, min or whatever taxi when cold. Anybody really know? I can kinda see both points of view.Thanks. Dave
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LifeofReiley
Well Known Member
90+ before takeoff if you Love your engine....
lockeed
Well Known Member
Here's a couple pics of the air valve I just built today...
Now, sorry for the crapy Iphone pics... It also need some finishing touches on the metal and rivets, and some sanding and paint. Right now it's on primer only.
I indicated with a red line how the cable is gona operate the valve. Of course, there's some hardware involded which is not in the picture.
I choosed a ratchet type, friction lock cable from ACS which is gona do the job just fine. I also installed 2 half rings inside the valve, one on each side of the butterfly door - opposite from each other, so the door can close against them and form a tight seal.
I didn't used the flimsy aluminium 3 " tube used by some... I choosed a 3" galvinized exhaust pipe. It's rock solid and I know it's gona last as long as the plane without ever wearing out... It weight about a pound so, I just didn't see the point of trying to save weight on this.
That's pretty much it.
Now, sorry for the crapy Iphone pics... It also need some finishing touches on the metal and rivets, and some sanding and paint. Right now it's on primer only.
I indicated with a red line how the cable is gona operate the valve. Of course, there's some hardware involded which is not in the picture.
I choosed a ratchet type, friction lock cable from ACS which is gona do the job just fine. I also installed 2 half rings inside the valve, one on each side of the butterfly door - opposite from each other, so the door can close against them and form a tight seal.
I didn't used the flimsy aluminium 3 " tube used by some... I choosed a 3" galvinized exhaust pipe. It's rock solid and I know it's gona last as long as the plane without ever wearing out... It weight about a pound so, I just didn't see the point of trying to save weight on this.
That's pretty much it.
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David-aviator
Well Known Member
One problem I have had with all these numbers is winter flying without preheat. You wouldn't be flying much.
Even on a day with temps in the 30's, it would take an hour of ground ops to get OT up to 125F on the 7A with the air flow to the cooler shut off. Piper recommends a baffle plate over the cooler with temps below 30 and even at that, they have to say it is is ok to fly if pressure is normal.
I read one engine guru recommending 140F minimum for take off. I sat in a run up pad one cold day for 45 minutes just to prove the recommendation was BS.
No question, preheat is good for any engine and I use it. You taxi out with 100+ and that's a good feeling. But these engines are not at all wimpish. If preheat was not used and the gage is off the peg, the engine is ok for flight.
What a cold start does for engine life is another issue. Mike Bush at OSH made a pretty good case for preheat in that he calculated there is much engine wear when starting a cold cold weather without it. Waiting for a minimum temperature for take off is not going to undo the damage already done by starting that cold cold engine without preheat.
Ron Lee
Well Known Member
Install a sump heater. Currently I am using a Wolverine heater
http://shop.wolverineheater.com/USA-Products_c4.htm
http://shop.wolverineheater.com/USA-Products_c4.htm
jthocker
Well Known Member
Opinions and EXPERIENCE!!! Thanks David, I too follow the manufacturer's recommendations.
az_gila
Well Known Member
Under the Operating Conditions section in the Lycoming O-360 Operator's Manual there is a little note..
* - Engine oil temperature should not be below 140F (60C) during continous operation.
So, does "continous operation" include take-off?
lockeed
Well Known Member
For me, it make sense that for the first minute or so after starting the engine, you let it run at minimum idle. Then, you bring it up to 1K while leaning properly.
When an engine has been pre-heated, you'll see the temp gauge getting up right away.
I also use a pre-heating pad, at least an hour before flight, but usualy 3-4 hours... And I use a heater to warm up the engine by the exhaust vent under the lower cowling.
It always starts right up. But for some reason, if I need to go and put some fuel in before flight, when I want to restart it after its been shut down for 15 minute or so, it turns for 5-6 seconds before starting....??
When an engine has been pre-heated, you'll see the temp gauge getting up right away.
I also use a pre-heating pad, at least an hour before flight, but usualy 3-4 hours... And I use a heater to warm up the engine by the exhaust vent under the lower cowling.
It always starts right up. But for some reason, if I need to go and put some fuel in before flight, when I want to restart it after its been shut down for 15 minute or so, it turns for 5-6 seconds before starting....??
lockeed
Well Known Member
No this mean "cruise". At least to me.
David-aviator
Well Known Member
Dave,
I just went over my notes from his lecture and apparently there was no mention of rpm after start. What he said was a cold start below 32 was a "felony" and a start below 20 a "capital offense" so far as engine wear is concerned.
His reasoning is the aluminum pistons react to heat and expand quicker than do the steel cylinders which causes metal to metal contact and excessive wear on the cylinder walls. For sure the normal clearance tolerances within the combustion chamber are compromised during a cold start.
That all makes good sense, at least to me. RPM probably doesn't make much difference except less rpm might mean less damage until temperatures stabilize.
I'm with Dave D. above. The start is what kills and that has nothing to do with oil temp since it's just sitting in the sump. What remains on internal services is what's there when you start. Running to a higher temp doesn't ameliorate start wear.
So everyone must be concerned with circulation. Well, what of viscosity effects? That hasn't been mentioned. And just where are you measuring the oil temp? At what temperature you like is the temperature what it should be by some undefined standard.
Got pressure? Oil's o.k. Thinner helps circulation, sure, but I like seeing 200+ CHTs before full power, oil is what it is.
John Siebold
So everyone must be concerned with circulation. Well, what of viscosity effects? That hasn't been mentioned. And just where are you measuring the oil temp? At what temperature you like is the temperature what it should be by some undefined standard.
Got pressure? Oil's o.k. Thinner helps circulation, sure, but I like seeing 200+ CHTs before full power, oil is what it is.
John Siebold
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az_gila
Well Known Member
Lycoming Operator's Manual does define the oil temp. measuring point.
It's says "Oil Inlet Temperature" - right by the usual temp. probe location...
...and the viscosity is covered by SI 1014 which specifies reccommended oil grades for differing ambient air temperatures.
For those winter fliers, the grades change for below 30F and below 0F ambient.
Jerry Cochran
Well Known Member
I use one of those oil-filled electric radiators right under the cowling outlet, and adjust thermostat to keep FWF at 70f. Some seeps into cabin keeping panel warm also.Blanket over top cowl. Uses surprisingly little power, by the time doing preflight, taxi out, runup Oil temp on takeoff usually 120f.
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NickAir
Well Known Member
Oil Temp
Jerry,
I like your heater idea. A small electric heater was placed to blow into the engine compartment through the exhaust/cooling opening. This worked, although took time, over an hour if freezing out. Still have to wait.
Your idea, with the oil radiator, is always on. Is that correct?
Jerry,
I like your heater idea. A small electric heater was placed to blow into the engine compartment through the exhaust/cooling opening. This worked, although took time, over an hour if freezing out. Still have to wait.
Your idea, with the oil radiator, is always on. Is that correct?
