Should you lean slightly when taxiing?

D

DMD3.

Pre-takeoff checklist
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DMD3.
In the Skyhawk I learned to fly in, one of the instructions in the taxi checklist was to lean the mixture one knuckles widtch away from the dash when taxiing (then enrich it fully upon the engine runnup).

Other instructors at different FBOs say it's not necessary to do this.

The purpose was to keep the mags from getting carbon build-up, as it was a trainer aircraft and did lots of touch-and-go's.

Is this a good idea for any aircraft?
 
DMD3. said:
In the Skyhawk I learned to fly in, one of the instructions in the taxi checklist was to lean the mixture one knuckles widtch away from the dash when taxiing (then enrich it fully upon the engine runnup).

Other instructors at different FBOs say it's not necessary to do this.

The purpose was to keep the mags from getting carbon build-up, as it was a trainer aircraft and did lots of touch-and-go's.

Is this a good idea for any aircraft?
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Elevation of the airport you fly out of..:dunno::dunno::dunno:
 
I don't know about "any aircraft" but I've aggressively leaned all aircraft I've flown while on the ground. If it doesn't die when the throttle is advanced, then it's not leaned enough. "Leaned slightly" is not enough.
 
I lean immediately (well maybe 5 to 10 seconds) after starting and making sure we have oil pressure and it is running smoothly. It should be lean enough that throttling to over about 1500 rpm will kill the engine.
 
DMD3. said:
The purpose was to keep the mags from getting carbon build-up,

Is this a good idea for any aircraft?
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Leaning has no effect on the magnetos.......none.


And, yes you should lean the engine on the ground to keep from fouling the spark plugs.
 
Lean it as much as you can, you're going to help your plugs and you can't hurt anything at taxi power settings.
 
If I am running Massive Plugs and I don't lean aggressively, they will foul (Lycoming O-360 in a cardinal, which runs overly rich at idle). It isn't so much of a problem with Fine Wire Plugs but I lean nonetheless. The mags don't care. It's the plugs that'll foul with too much of a rich mixture.

DMD3. said:
The purpose was to keep the mags from getting carbon build-up...
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timwinters said:
I don't know about "any aircraft" but I've aggressively leaned all aircraft I've flown while on the ground. If it doesn't die when the throttle is advanced, then it's not leaned enough. "Leaned slightly" is not enough.
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That's what I do, and you will never forget to richen the mixture during your run-up or take off.
 
Slightly? No. Aggressively? Yes.
 
We have to on the Archer, fouls very quickly otherwise and before shutdown, take it up to 1800rpm for approx 20 seconds then kill it with the mixture.
 
After startup, I lean so that the engine will not run above about 1100 rpm while taxiing. My plugs stay so much cleaner that way.
 
I lean aggressively in my mooney (O-360 lycoming). Once it starts, I pull back quite a bit. I give it just enough mixture to keep it from stumbling.
 
Do you lean as aggressively after landing and while taxiing back to the tie-down?
 
Every thing written here so far is an opinion. where will you find the proper operating procedures for your engine?

If you are giving advice, shouldn't you give a reference?

Or is it "my CFI told me"
 
DMD3. said:
The purpose was to keep the mags from getting carbon build-up, as it was a trainer aircraft and did lots of touch-and-go's.
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Who taught you that, and what reference did they use?

I want to know how carbon caused by burning fuel get's in the mag?
 
Tom-D said:
nope not even.
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Curious as to why. I still lean on the ground, but mostly due to habit and often I'll fill up with 100ll when traveling. Good to be consistent. (Leaning in the air is a given.)
 
Tom's binge positing again!

Or is it binge drinking again! :rolleyes2:

Or just Tom being Tom again?

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I'm sure Ted will be along to give us the technical side of this issue. In the the world of big bore continentals leaning for taxi has to do with plugs exhaust valves and cylinder wall damage. The way I understand it is that the fuel injection system is setup overly rich to help with starting. So, there is more fuel in the cylinders than can be fully burned at idle.

For me, its as the engine starts to warmup I lean until the engine sputters then enrichen. It stays that way until takeoff. When landing I never go full rich unless there's a go around. I stay with the lean setting through approach, landing and taxi. Stays lean until shut down. YMMV
 
This place can sometime suck in terms of getting some solid advice.

Manufacturer's guidelines should generally be followed, except where leaning is concerned whether in flight or on the ground. Leaning in flight is a relatively complex issue, emphasis on 'relatively'. Forget that for now.

Leaning on the ground, for any and every piston engine, is a good thing. Doing it 'aggressively' removes the one risk. Aggressively means leaning so much that the engine stumbles and quits if power is applied. What do I mean by 'power'? More power than required for normal taxi operations.

What's the risk is leaning on the ground? The risk is taking off with the engine leaned too much which could result in detonation which could ruin your engine. By doing it aggressively you make it impossible to apply full power and take off. Instead, if you forget to enrich the mixture for takeoff, the engine will stumble and quit which will either 1) force you to push the mixture control to continue the takeoff run or 2) force you to abort the takeoff. All will be well if you remember to enrich the mixture properly before takeoff. A good place to do that is during your run-up.

Leaning is good for everything on the ground before takeoff or after landing. Some CFIs advise differently because it's not their airplane and/or they don't know better. Leaning aggressively removes the risk of high power ops with the engine too lean.

All this can be picked apart as desired but it's a real and good answer for your flying. As an owner, you'll do it for your pocket book.
 
Lean when taxiing -- yes: Lean left when turning left and lean right when turning right. You have to lean more than slightly, though, in order to be able to take the turns faster. :D

The mags won't suffer carbon buildup as long as you change the magneto fluid regularly and/or recharge them with premium wheel gas. :smilewinkgrin:

But seriously, those guys telling you not to lean on the ground are fruit-loops, in my opinion. You cannot harm the engine by leaning it on the ground and you will save a few drops of fuel and help prevent the plugs from fouling.

If you forget to enrichen the mixture because you weren't using the checklist for runup or for takeoff, then you've got other problems that won't be fixed by not leaning.
 
In 15 years of flying behind low-powered Continentals, I lean in all phases except TO, and I've never had even the slightest hint of a stuck valve. Never had more than a fouled plug that didn't clean up with a full power run up & lean.

On the other hand I've met several O-200 drivers who have suffered stuck valves and invariably their answer about leaning is...vague. They are the ones who have the rope trick done to allow them to continue to their ultimate destination. It's enough empirical evidence to convince me that leaning is a good thing for engines that drink leaded fuel.
 
I lean forward.

On many planes if you DON'T lean to the point of the engine almost stumbling you are doing almost NOTHING. The mixture control doesn't affect idle power settings (which is why full out is called idle cut off).
 
Yes. Lean on the ground aggressively at all times. Aggressively enough that if you advance the throttle without enrichening, it will die.

At home I even lean for start. Not as aggressively but it'll start easier when it is halfway out at 6000 MSL. Mechanic showed us that trick years ago. Works very well. It's too rich at full rich to run well, makes sense it'll start easier at something sane also.
 
I lean forward to go faster.:D Seriously though, I lean so hard, that if I advance the throttle the engine will stumble.
 
My 0-235 will foul plugs like no tomorrow unless leaned on the ground. I yank the mixture out probably 3/4 of the way while farting around on the ground, no fouling issues since... I got some before pics of my plugs that are fouled, I'll see if I can find and post them later. Be amazed at how much lead accumulates in a plug! :eek:
 
I lean very aggressive on the ground to keep my plugs clean. So much if you tried to take off the engine would die.
 
GlennAB1 said:
Follow the manual. Fuel actually helps cool the cylinder/head, and at low RPM leaning can be bad.
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right...............................................................................
 
Taiser said:
My 0-235 will foul plugs like no tomorrow unless leaned on the ground. I yank the mixture out probably 3/4 of the way while farting around on the ground, no fouling issues since... I got some before pics of my plugs that are fouled, I'll see if I can find and post them later. Be amazed at how much lead accumulates in a plug! :eek:
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I wish I'd taken pics a couple weeks ago after my friend's 152 was running a skosh rough. When we pulled a certain lower plug, the lead was overflowing. None of us had ever seen such a crudded up plug; it had been cleaned at annual 6 months prior. I honestly don't know whether he leans or not on the ground. I'd like to see if yours compare!
 
Lean Forward, that is the only answer
 
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