Warming up engines
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Warming up engines
How long do you AME's recommend warming up an engine prior to flight?
If I reference the C172 POH, it says, "If the engine accelerate smoothly, the airplane is ready for take-off." Later it says, "...long periods of idling may cause fouled spark plugs."
I understand that there is trade off between adequate lubrication and plug fouling.If the first sentence is correct, than only a minute or two is required, but this doesn't seem adequate at all. I have always waited until the oil pressure indicates a temperature.
If I reference the C172 POH, it says, "If the engine accelerate smoothly, the airplane is ready for take-off." Later it says, "...long periods of idling may cause fouled spark plugs."
I understand that there is trade off between adequate lubrication and plug fouling.If the first sentence is correct, than only a minute or two is required, but this doesn't seem adequate at all. I have always waited until the oil pressure indicates a temperature.
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Re: Warming up engines
With todays multi-grade oils, if it is room temp it will flow just fine, and therefore it is more of an issue of getting the cyl. temps up (1-3 min)
If the oil is cold, then I would suggest waiting till it shows on the gauge as you mentioned !
If the oil is cold, then I would suggest waiting till it shows on the gauge as you mentioned !
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Re: Warming up engines
I’ve always followed the practice of letting the engine warm up FULLY before I pour the coals to ‘er. Lean it out on the ground to prevent plug fouling, do a good run up if it’s cold out, and once the oil temp is in the green, give’er.
Re: Warming up engines
Depends.
I am assuming you are referring to typical horizontally opposed lycoming/continental type engines.
The radials require a different procedure.
Personally with the O engines, I like to see CHT and oil temp at the bottom of the green, and the oil pressure enough below red line to allow for it to remain bellow red line on the runup.
As an aside, some of the preheat systems are good enough that everything is in the green 30 secs after start.
I am assuming you are referring to typical horizontally opposed lycoming/continental type engines.
The radials require a different procedure.
Personally with the O engines, I like to see CHT and oil temp at the bottom of the green, and the oil pressure enough below red line to allow for it to remain bellow red line on the runup.
As an aside, some of the preheat systems are good enough that everything is in the green 30 secs after start.
Last edited by trey kule on Mon Oct 16, 2017 4:36 pm, edited 1 time in total.
Accident speculation:
Those that post don’t know. Those that know don’t post
Those that post don’t know. Those that know don’t post
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Re: Warming up engines
Radials LOVE long, slow caresses! They bitch and belch and complain and will not follow your lead UNTIL you have been patient with her idiosyncrasies Hmm, Am I talkin about engines or women?
Re: Warming up engines
If the pressure gauge is indicating temperature, it's probably wired up wrongly :-OBede wrote:I have always waited until the oil pressure indicates a temperature.
DId you hear the one about the jurisprudence fetishist? He got off on a technicality.
Re: Warming up engines
I follow the POH and don't wait for oil temperature indication before departing. If I operated in cold temperatures or wasn't sure that the oil was the proper grade for the temperature then that's a different story.
Having said that, one of the RV-10s I fly has an IO-540 that the owner blew the prop seal out after taking off with cold oil. He now will not takeoff with an oil temperature below 70°F. I downloaded the engine data from the event and the oil pressure was indeed way above redline. I would think this indicates a problem with the pressure relief valve but that's how the owner has decided to deal with it.
Having said that, one of the RV-10s I fly has an IO-540 that the owner blew the prop seal out after taking off with cold oil. He now will not takeoff with an oil temperature below 70°F. I downloaded the engine data from the event and the oil pressure was indeed way above redline. I would think this indicates a problem with the pressure relief valve but that's how the owner has decided to deal with it.
Re: Warming up engines
My personal SOP is to wait until I have at least one CHT at 200F (courtesy the Insight engine monitor) before I taxi. Pre-taxi preparations are usually enough for this, except on the very coldest days.
I look for the oil temperature to be in the green range (starting at 120F) before takeoff. Taxiing and runup will usually accomplish this, except, again, on the very coldest days.
...laura
I look for the oil temperature to be in the green range (starting at 120F) before takeoff. Taxiing and runup will usually accomplish this, except, again, on the very coldest days.
...laura
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Re: Warming up engines
20W50 oil in a cold engine will exceed the upper oil pressure limit when the engine RPMs get higher. That's even at 1200-1500 rpm if the engine is too cold. The injected Lycomings will accept a lot of throttle when they're still very cold.
Oil pressure should be running in the middle to lower end of the normal operating range in cruise. You just have to make sure the oil is warm enough that the pressure won't exceed the limits at take-off (or run-up or any rpm with a cold engine).
Back when I was routinely operating piston engine'd aircraft, there was one particular engine that I warmed up by oil pressure. After starting, I'd set about 700-800rpm and note the oil pressure. As the oil warmed and the pressure decreased from the red line, I would increase the rpm gradually, keeping the oil pressure slightly below redline, until around 1200 rpm or so. We leaned quite aggressively on the ground as it takes a while to warm up an engine from 5*c
Oil pressure should be running in the middle to lower end of the normal operating range in cruise. You just have to make sure the oil is warm enough that the pressure won't exceed the limits at take-off (or run-up or any rpm with a cold engine).
Back when I was routinely operating piston engine'd aircraft, there was one particular engine that I warmed up by oil pressure. After starting, I'd set about 700-800rpm and note the oil pressure. As the oil warmed and the pressure decreased from the red line, I would increase the rpm gradually, keeping the oil pressure slightly below redline, until around 1200 rpm or so. We leaned quite aggressively on the ground as it takes a while to warm up an engine from 5*c
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Re: Warming up engines
I found the best way to warm an engine in very cold temperatures was with engine covers and a herman nelson.
The hardest thing about flying is knowing when to say no
After over a half a century of flying no one ever died because of my decision not to fly.
After over a half a century of flying no one ever died because of my decision not to fly.
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Re: Warming up engines
Another one of those names that cannot be related to anything material, unless you burnt your pant leg off with one ! Might as well call it a Canadian Quickie or a spuzzmodit !!!herman nelson.
Re: Warming up engines
H.w. nelson co. inc. was the creator.crazyaviator wrote:Another one of those names that cannot be related to anything material, unless you burnt your pant leg off with one ! Might as well call it a Canadian Quickie or a spuzzmodit !!!herman nelson.
Re: Warming up engines
At the cost of fuel these days, I preheat as much as possible before firing up below 0!
"Carelessness and overconfidence are more dangerous than deliberately accepted risk." -Wilbur Wright
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Re: Warming up engines
...was told to always wait until temp shows 75F before taking off
..that was 20 years ago and stayed with it since...
Cheers
..that was 20 years ago and stayed with it since...
Cheers
Re: Warming up engines
I find the heated hangar works quite well!
Only downside, when you leave your heated hangar and stop for awhile in the winter somewhere and despite the engine blanket you come to find your old battery was only hanging on because of the warm hangar.
Only downside, when you leave your heated hangar and stop for awhile in the winter somewhere and despite the engine blanket you come to find your old battery was only hanging on because of the warm hangar.