How far do you lean while on the ground before takeoff

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woxof

Pre-takeoff checklist
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woxof
Just reading an article about leaning the engine during ground ops and the pilot suggests leaning as much as is reasonably possible. His reason is that eventually, there will be a time that you will forget to go to the proper mixture setting for takeoff. When this eventually happens, instead of there being a serious takeoff issue, the engine will simply falter almost immediately upon full power application with no harm done at which point full rich(or as required) can be selected and the takeoff continued normally.
 
woxof said:
Just reading an article about leaning the engine during ground ops and the pilot suggests leaning as much as is reasonably possible. His reason is that eventually, there will be a time that you will forget to go to the proper mixture setting for takeoff. When this eventually happens, instead of there being a serious takeoff issue, the engine will simply falter almost immediately upon full power application with no harm done at which point full rich(or as required) can be selected and the takeoff continued normally.
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I'll usually lean a bit on a hot day. If I have an engine monitor I'll get precise otherwise a couple turns for me.
 
This is John Deakin's philosophy. It makes sense to me, and what I do.
 
I pull about 2” in the 182 for taxi. If you get the habit of putting your hand across the throttle, prop and mixture as soon as you go full power You will never takeoff lean
 
Very aggressively, I do have engine monitor though. My engine have tumbled once or twice when I went overzealous with taxi speed.


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At our altitude I ascribe to that train of thought, too. Otherwise plugs get fouled.

If it’s so lean it’ll die when I add power, that means I totally screwed up a checklist somewhere. A double check basically.

This is with my carbed O-470 too of course. And it makes it obvious when it’s too rich on the ground. It’ll sound more like a Harley than an airplane. :)

Other engines and fuel-air systems may not like this. And I always do what the owner wants within the bounds of safety.

And then there’s the joke about “Denver rich” when the checklist calls for full rich. That’s about an inch and a half back in my airplane for safe operation and maximum power at takeoff with no worries about detonation at all.
 
Once the engine is running smoothly at 1000rpm after startup, I give the mixture a big pull, almost all the way to idle cutoff, as Mooneys are notorious for being very rich near idle. Sometimes when I'm back taxiing uphill on 21 (our runway is higher at the ends than the middle - V-shaped) I sometimes have to give a few turns richer or it won't rev past 1200rpm or so.

Collegedale-Airport.jpg

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As much as I can. I'm not sure you can do any damage to an engine running at idle.
 
When properly setup a TSIO-360 will give a 25 to 50 rpm rise when leaned at idle. Go much further and it dies when cold. So leaning is simple, just pull until you get into the rpm rise. If you forget to go full rich for departure you are on the way to a rapid, spontaneous and somewhat spectacular engine disassembly.
 
woxof said:
How far do you lean while on the ground before takeoff
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As far as the seat back will let me. I like to lean back heavily, like certain thug drivers. It makes me look very cool during taxi. ;)

But all seriousness aside: the answers here are all good. Lean as far as the engine will let you, your plugs will thank you.
And when you do your run-up, lean for best power and you'll be good for take-off with another turn clockwise on the knob (or 1/4" push on a lever).
 
Another carb'd 182, those plugs are getting soaked in gas during idle and taxi if you don't pull the mixture way out. And you'll notice it at the pump too if you're doing lots of taxi backs and waiting to takeoff.

After we learned how much to lean after startup and good oil pressure we also noticed the mag checks are much more consistent.

I have stalled the engine on taxi once because I leaned too much and later gave it some power to get moving...if that gives an idea of how aggressively lean it is.

An easy one to forget is to lean right after landing too when taxing to put it away.
 
Slightly in North Carolina. Much more on the plains in Colorado. Almost to engine starvation in Leadville. Most guestimated.

almost 30 years flying. 20 years in Colorado, Never failed to set the mixture to the proper setting for takeoff. Not even once.
 
Once the engine is started, I pull the mixture as far back as I can until the engine stumbles. If the engine then stumbles when you go to advance the throttle than you’ve done your job.

This is especially important if you have a relatively long taxi. You’re not going to hurt the engine by hard leaning on the ground.
 
I don't have an engine monitor so as soon as the engine smooths out I set the RPM at 1000 and then lean until the RPM maxes out and then starts to fall. Then I pull the throttle back to 1000. I have first hand knowledge that full power entering the R/W will cause the engine to falter if it is leaned this way.
 
And since no one else has said it, I lean a little to the right but not to far that I fall over.
 
How far do you lean while on the ground before takeoff.

Hmm, well, really just once I guess to check the engine fuel sump on Cessnas so one there, reckon 3 times on a Piper....;):)
 
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I'm at mostly at sea level. For my continental O-470-R, set idle to 1000 rpm and lean until ~1200 rpm and reset idle to ~900 rpm.

Fully agree with the earlier post about soaking the plugs before take-off shows lack of understanding of systems. Each annual, my IA is impressed with the condition of the plugs and says something about proof of effective use of the mixture control. Yeah for me. :7)
 
Aggressively for taxi to avoid fouling... and, if you're using your checklist, as you should be, (the written one, not the one in your bony head) you won't ever forget to set to best power for takeoff... by the way, @Tantalum how'd you get that picture of my interior?
 
The rental I fly consistently will shake horribly on the R mag check if I don't lean it pretty aggressively for a couple minutes at taxi/runup.
Apparently no one else ever leans it.
I take it out, all the way to stutter, then 3 turns in.
Seems to work, but I'm not sure if that's too aggressive.
 
Skyrys62 said:
Apparently no one else ever leans it
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I think it was an undertaught part of training, I wasn't taught about proper leaning technique until I got my instrument rating, and I think that was primarily because the instructor was also the owner of the plane. Now I lean like everyone else on this thread has mentioned, pretty much until the engine is sputtering, then just a touch rich so I can taxi
 
I lean for taxi, but I don't do the leaning until stumble. The reason is, I have a taildragger and sometimes need close to full power when taxiing to overcome the effects of tailwinds and otherwinds, trees and ditches etc.
 
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A couple of times I leaned for ground ops then had it die when I nudged the throttle for taxi.
 
I have no choice the fadec system ,does all that stuff automatically.
 
I fouled plugs twice early on in my training when I wasn't leaning at all. Now I lean on the ground pretty much the same way I lean in the air. Pull it til it starts to cut out then back in just enough for smooth operation. I takeoff and climb at full rich and cruise at 65% and lean as described.
 
I lean it until the engine coughs and then push it back in a little so it's running smooth. I don't know "how much" that is.
 
I pull the mixture abiut 2/3 - 3/4 towards cutoff. If taxiing uphill (3-4°), I often have to push it towards rich.

This applies whenever the engine is running on the ground and I'm not either doing a runup or taking off. Repositioning on the airport? Taxiing for fuel? Heading towards the runway? Just landed and headed for ramp, hangar or parking? Yes to all.

Can't lean a 172 as much as I do my Mooney or the engine dies, which is embarrassing . . . . .
 
I let the engine warm up about a minute while I grab ATIS and run thru my pretaxi list. Then I lean until RPM drop and richen up a half turn.

I too was never taught to lean by my first instructor. On my first solo, I was in a conga line of other trainees. By the time I did my run up, the mag drop was bad. Taxied back and instructor couldn’t clear it up. Next day instructor showed me how to lean and how to clear it up (higher RPM than run up and aggressive leaning, and for about 1-2 minutes).

I have taken off once with it leaned. I was behind an ILS hold line that was a long distance from the RWY threshold at a non towered field. Did my run up. I go full rich for that, and it’s on my checklist. Ready to go. Cross the ILS line and a Lear Jet announces 2 mile base (never said anything before). Cirrus was in the pattern but let’s him in, then it’s the Cirrus’ turn to land. I should have not done this, but I leaned cuz I was sitting there so long; It was a halfazz lean just for the short duration and taxi. I even left my hand on the knob, but forgot about it after the 2nd plane was landing. When I went to enter the runway, I did not go back full rich.

I was not lean enough to stumble on takeoff. At about 1000 ft AGL, I realized the lean condition due to my flow & checklist.

I do have a before takeoff checklist that calls for rich at run up and a second rich check before crossing the hold line. I had already crossed the ILS hold and had no more checklist crutch.

I need to get my pretakeoff flow on. I like the hand on 3 knobs on takeoff. Gonna use that from now on.

The above is typical accident chain stuff. Something changed:
- Long ILS hold short
- Unannounced plane entering the pattern
- A certain amount of distraction for a Lear approaching (VFR day, but am I obstructing the ILS?)
- Delay in takeoff after crossing hold short
- Halfhearted re-lean
- No flow pilot conditioning pre takeoff
- Checklist done/put away after crossing hold short line
 
swingwing said:
I pull about 2” in the 182 for taxi. If you get the habit of putting your hand across the throttle, prop and mixture as soon as you go full power You will never takeoff lean
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???? Which model? At least some 182s call for leaning for takeoff power - I seem to remember a CAP 182 I flew quite a but had that in the POH? I think/think I leaned for a certain fuel flow if I recall.
 
Back till it stutters, than forward enough to smooth out, at the taxi power settings you're at for taxi you can't hurt anything leaning too much.


Sundancer said:
???? Which model? At least some 182s call for leaning for takeoff power - I seem to remember a CAP 182 I flew quite a but had that in the POH? I think/think I leaned for a certain fuel flow if I recall.
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That.

You're going to need to lean for takeoff in high DA conditions for most any piston plane.
 
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