Best way to lean mixture?

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josephades

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What is the best way to lean your mixture? I have an EGT but I never really understood how to use it. I was once told something about "50 degrees cooler" but I don't understand how to determine that, nor how to read the EGT.

I don't have a digital RPM gauge, so when I lean, I wait until there is roughness in the engine. Then I richen the mixture about a millimeter or two above the point where you no longer hear engine roughness or notice any RPM drops. Note that I do not reference the EGT.

Please enlighten me if I am doing anything wrong, and how to adjust my habit. I've been getting about 9.12 gallons per hour in a piper archer using this method.

I was also taught back in my training days about something called "best economy" to save even more on fuel, but every instructor gives me a different method on how to lean for best economy. My very first instructor taught me that you have the throttle advanced full forward, and then you use the mixture control to adjust for the RPM you want. Then reduce the throttle slightly if necessary. When I attempted this method - you feel "engine roughness" and I did not feel comfortable at all, and just ended up flying the way I am used to. Would definitely appreciate if someone can clarify this as well

Thanks


EDIT- found another thread with a very similar posting. I will monitor that thread instead. https://www.pilotsofamerica.com/community/threads/proper-leaning-technique-cherokee-140.98952/
 
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The telling factor is which type of fuel system you have. do you know?
I believe the Archer is a 0-360-?
which is a carburetor system, these have an un-even fuel distribution to each cylinder. when you pull to lean one cylinder will be the leanest, and go to a lean miss fire first on the Lean side of peak (the highest temp you see on the EGT) but the richest may still be on the rich side of peak and running much hotter than the rest of the cylinders. so when you pull to feel the vibrations then richen, to smooth you may have all the cylinders running in the best power range just rich of peak. this will short life the cylinders.

go to EAA page and search for the pelican's perch, and read it.

http://www.avweb.com/news/pelican/182146-1.html

http://www.avweb.com/news/pelican/182192-1.html
 
To lean according to EGT, you need even flow (fuel injection) and an EGT on each cyclinder. What you are doing is fine. Lean to RPM drop and enrichen slightly.
 
You'll get as many answers as polots.

I lean agressively, and haven't found gauges to help. In straight and level flight at cruise speed and altitude I slowly lean with a vernier mixture control until I get best RPM and then lean some more until the RPM drops a little bit more.
 
Not sure if you have a analyzer, but I lean for CHTs

Based on my DA, I lean to around the burn for my settings and fine tune for CHTs.

Without a analyzer, just go off ear and feel, lean to ruff, a few screws in to smooth, and another one or two.

Per the LOP vs ROP debate, whatever make a decision for yourself, but all the companies I've worked for wanted ROP, unless I'm need total max range (like crossing a ocean, or some huge desert, I'm running ROP. Don't really think one is that much better than the other engine health wise, ROP makes a little more power and is a little easier.
 
Lean to rough, rich to smooth. You are doing it right, unless you have multipoint EGT. -Skip
 
Unit74 said:
I don't lean. I fly a turbo.
Click to expand...

Yeah we've noticed....
Vatican03_3437322b.jpg

*Lower left: TIT overtemp. Turbo piston owner, as seen during LOP cruise attempt.
*Top center: Cringe face {not visible} by pilot watching his "GAMI $$$PREAD" on 10AMU "monitor" :D
 
And people wonder why leasebacks are a bad idea... ;)

Joseph, what does the POH say for the Archer you're flying? Let's start there. If it's in there, you should know it or be able to look that up.
 
There's not enough coal on that shovel. MUST be a TIO360 not a TIO540.



hindsight2020 said:
Yeah we've noticed....
Vatican03_3437322b.jpg

*Lower left: TIT overtemp. Turbo piston owner, as seen during LOP cruise attempt.
*Top center: Cringe face {not visible} by pilot watching his "GAMI $$$PREAD" on 10AMU "monitor" :D
Click to expand...
 
LOP only works on all cylinders when you have an fuel injection with calibrated fuel nozzles, and a EGT gauge on each cylinder. that is the only ay you can get even fuel flows to all cylinders.
The Experimental folks are going to the SDS system. http://sdsefi.com/specific.html
 
Amateur here...
I do what I was taught in my transition training (fuel injected Io520k w/o engine monitor). I lean to find peak EGT ( before it starts going back down - this happens before roughness for me). Then I enrich 50 degrees (2 notches in EGT) and leave it there.

Sent from my XT1080 using Tapatalk
 
denverpilot said:
And people wonder why leasebacks are a bad idea... ;)

Joseph, what does the POH say for the Archer you're flying? Let's start there. If it's in there, you should know it or be able to look that up.
Click to expand...

Leaseback piston turbos sound like an outstanding idea. They can probably be leaned just fine - fly it like you stole it... ;)
 
linuxjim said:
Amateur here...
I do what I was taught in my transition training (fuel injected Io520k w/o engine monitor). I lean to find peak EGT ( before it starts going back down - this happens before roughness for me). Then I enrich 50 degrees (2 notches in EGT) and leave it there.

Sent from my XT1080 using Tapatalk
Click to expand...
That's generally understood to be the worst place to run an engine, especially with higher power settings.
 
Cpt_Kirk said:
That's generally understood to be the worst place to run an engine, especially with higher power settings.
Click to expand...
Interesting... I'll go back and read the articles listed here. Always interested in learning and adjusting as needed. Guess I took for granted that my instructor had over 6k hours in type and knew what was best for the plane.

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linuxjim said:
Interesting... I'll go back and read the articles listed here. Always interested in learning and adjusting as needed. Guess I took for granted that my instructor had over 6k hours in type and knew what was best for the plane.

Sent from my XT1080 using Tapatalk
Click to expand...
That's just it. Keep reading; keep learning. The more you know, the better off you'll be.
 
Every airplane is different so you'll need to learn yours. For example in my Cherokee, after start I lean for taxi which is when the top of the lever is even with the "X" in mixture. Then at run up I'll lean until it stumbles then richen until it smoothes out plus a smidge more.


Incidentally, who knew that "smoothes" is not a word?
 
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Timbeck2 said:
Every airplane is different so you'll need to learn yours. For example in my Cherokee, after start I lean for taxi which is when the top of the lever is even with the "X" in mixture. Then at run up I'll lean until it stumbles then richen until it smoothes out plus a smidge more.


Incidentally, who knew that "smoothes" is not a word?
Click to expand...
Weird thing is, we are down to two manufactures in most of our aircraft.
 
For the carb crowd: I have an 02 sensor in my exhaust that connects to an indicator light on the panel. Theory is that when the mixture is too lean there will be unspent 02 in the exhaust so the light comes on. You pull the red knob back slowly, the light comes on, you push knob in until the light goes out.
 
linuxjim said:
Amateur here...
I do what I was taught in my transition training (fuel injected Io520k w/o engine monitor). I lean to find peak EGT ( before it starts going back down - this happens before roughness for me). Then I enrich 50 degrees (2 notches in EGT) and leave it there.

Sent from my XT1080 using Tapatalk
Click to expand...

That's a lot of engine to not be running a monitor.
 
rolivi said:
For the carb crowd: I have an 02 sensor in my exhaust that connects to an indicator light on the panel. Theory is that when the mixture is too lean there will be unspent 02 in the exhaust so the light comes on. You pull the red knob back slowly, the light comes on, you push knob in until the light goes out.
Click to expand...

What AFR does your light come on?
 
Air/Fuel Ratio? I don't know because it doesn't measure that, it measures the presence of 02 in the exhaust.

Or so goes the limited information I have on it.
 
Unit74 said:
It was a joke... I lean too, but with no intercooler, it's very dainty. Usually my CHTs peak before TIT.
Click to expand...
Intercooler and gami's, I can usually lean it down to 8 gph if I don't mind going that slow. Before installing the gami's it would only go down to 10 gph.
 
Just the kit is $12k plus install for my rig. Not gonna happen.

Monday I flew at 50%, 115kts and about 10 gph. I needed the time more than the speed.

75% I get about 165 and 24 gph best power. That more than a Seneca!
 
Unit74 said:
Just the kit is $12k plus install for my rig. Not gonna happen.

Monday I flew at 50%, 115kts and about 10 gph. I needed the time more than the speed.

75% I get about 165 and 24 gph best power. That more than a Seneca!
Click to expand...

So 24GPH at 75%, that's nearly 400HP.

Watcha flying?
 
Never mind, miss read, 50% at 10GPH gives you about a 250HP engine
 
mtuomi said:
Surely 24gph on an TIO540 is not 75% or best power?
Click to expand...


24GPH is his max takeoff power, makes sense.




Rule of thumb

HP / 2 = PPH of fuel at 100%

So a 250HP engine

250/2= 125
125lbs (20 gallons) per hour of fuel at full power

Cruise at 70% power
20*0.7

Cruise burns 14GPH
 
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mtuomi said:
Surely 24gph on an TIO540 is not 75% or best power?
Click to expand...

I haven't tried leaning at 75%. I'm not that ambitious yet. Scratch that, I don't run it at 75% cept to see what she will do for a brief moment. I have been cruising at 55-65% mostly. Still trying to work out my Best MP/RPM combos. Only have 20 hours on it.
 
I lean until rough and then enriched until smooth in my archer. I fly a lot of long distant trips at higher altitudes, and my engine will never run rough. I lean to the RPM that I desire. Prior to leaning up high, I take the throttle off of full throttle to get better fuel distribution-maybe only 1/8 of an inch.

Fuel flow at 75% varies on Hobbs hours, but it always seems to be 8.8 GPH tach time using this method.
 
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