High DA takeoffs

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TBalch

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TBalch
The POH for my T182T provides no guidance for leaning for takeoffs from high DA airports. If there’s been a discussion here on the subject, I’d appreciate being directed to it.

Thanks.
 
TBalch said:
The POH for my T182T provides no guidance for leaning for takeoffs from high DA airports. If there’s been a discussion here on the subject, I’d appreciate being directed to it.

Thanks.
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I own a 182 fixed gear turbo-normalized. Lean for the appropriate power setting for take-off or landing relative to the manifold pressure setting. Example if take-off is turbo-normalized at density altitude 8000', and MP is set to 28-29"; then the engine thinks it's at sea level. The mixture would be close to full rich.

Consider searching for Savvy Aviation on YouTube for the Mike Busch EAA seminars on leaning. He discusses this topic and might be helpful as a starting place for application to your situation.

Careful of the POH recommended leaning options, they are tough on your engine. The Busch seminar covers how to lean according to your engine monitor to stay out of the dreaded "red box". Turbo's are actually easier to lean at high density alts, as typically you lean taxi, and then go nearly full rich under boost for take-off.

-David
 
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....... Because, that engine is making sea level power at whatever
DA the airplane feels. I do not lean any engines at full power while it is at SL regardless of what the altimeters reads.
 
Eric Stoltz said:
....... Because, that engine is making sea level power at whatever
DA the airplane feels. I do not lean any engines at full power while it is at SL regardless of what the altimeters reads.
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Don't be so sure of that. It may be "making power", but that does not translate to airspeed. I took off once at sea level, full, ehegm, gross on a hot, humid low pressure day and I was preying I was going to make it over the trees after I rotated. It was the only time in my flying I have ever regretted taking off. 2-300ft a min climb, CHTs going through the roof, making that engine earn it's HP rating. It still makes me sick thinking about it. The reason I stopped was cheap fuel and got that sucker as full as I could plus a full load of pax and bags. I actually rejected the first roll because I was not making enough speed on the roll. I exited, full power run up. Looked good and tried again. Could have been the last time I did.....
 
Unit74 said:
Don't be so sure of that. It may be "making power", but that does not translate to airspeed. I took off once at sea level, full, ehegm, gross on a hot, humid low pressure day and I was preying I was going to make it over the trees after I rotated. It was the only time in my flying I have ever regretted taking off. 2-300ft a min climb, CHTs going through the roof, making that engine earn it's HP rating. It still makes me sick thinking about it. The reason I stopped was cheap fuel and got that sucker as full as I could plus a full load of pax and bags. I actually rejected the first roll because I was not making enough speed on the roll. I exited, full power run up. Looked good and tried again. Could have been the last time I did.....
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I am very sure of it. I was regarding engine power/use alone, and not relating anything to airspeed.
 
Cessna T182T POH 4-31 (Normal Operations) states to have full fuel flow 24-26 gph. I have always been instructed to have full MP/ full gph on take-off in the T182T regardless of DA.
 
Stacey Hudson said:
Cessna T182T POH 4-31 (Normal Operations) states to have full fuel flow 24-26 gph. I have always been instructed to have full MP/ full gph on take-off in the T182T regardless of DA.
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What does it say about an emergency takeoff? :D
 
Unit74 said:
Don't be so sure of that. It may be "making power", but that does not translate to airspeed. I took off once at sea level, full, ehegm, gross on a hot, humid low pressure day and I was preying I was going to make it over the trees after I rotated. It was the only time in my flying I have ever regretted taking off. 2-300ft a min climb, CHTs going through the roof, making that engine earn it's HP rating. It still makes me sick thinking about it. The reason I stopped was cheap fuel and got that sucker as full as I could plus a full load of pax and bags. I actually rejected the first roll because I was not making enough speed on the roll. I exited, full power run up. Looked good and tried again. Could have been the last time I did.....
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Power and thrust are very different things.
 
It’s not surprising that the POH for a T182T would not discuss leaning the mixture. The whole point of a turbo is to provide the same pressure as a lower altitude (sea level) and, hence, the same amount of air (oxygen) for combustion.

Said another way, a turbo engine allows you to use the same fuel/air mixture and get good combustion as if you were at sea level. No leaning necessary.
 
I always lean on takeoff in a high density altitude situation. I also fly a an old 182 with a carburetor.

In the 70's when I learned to fly in Montana off of a 4,700' airport we always leaned the mixture when the temps got high. The difference in engine performance was very noticeable.

Maybe I've been wrong all these years. Wouldn't be the first time!
 
MauleSkinner said:
Power and thrust are very different things.
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That's


what



she



said.

saddletramp said:
I always lean on takeoff in a high density altitude situation. I also fly a an old 182 with a carburetor.

In the 70's when I learned to fly in Montana off of a 4,700' airport we always leaned the mixture when the temps got high. The difference in engine performance was very noticeable.

Maybe I've been wrong all these years. Wouldn't be the first time!
Click to expand...

In a normally aspirated, that is what you want to do. Turbocharged changes things.
 
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