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Quick leaning opinion - NOT LOP vs. ROP


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I know there are many posts about leaning but I did not want to hijack any of the other conversations with my specific questions. Plus this is not about LOP vs. ROP.

In the few years I have been flying my Mooney, and after trying to find the proper leaning techniques, I have been following one of the recommendation on this forum to work best for my engine (360-A1A with a JPI830):

8.5GPH LOP

12.5GPH ROP

NEVER 10GPH

And yes, I have been watching the videos about the red box or envelope, whatever you want to call it.

I also have found that my engine likes best the 12.5 setting. All temps, power < 70%, sound, etc. feels nice and smooth.

When OAT is high (about >90F) if I go LOP (8.5GPH) my oil temp goes to 200F or above although my CHTs are always great (350/360). So, I stick with 12.5GPH.

During the last few flights I have been trying to fine tune my leaning technique again. So I do the usual mixture pulling until rough and then add some, to end up at around 10GPH! Even using the JPI procedure. Because 10GPH should be a no-no I push back to 12.5GPH.

Is it ok? Also, how do I go to LOP if, according to the JPI procedure, I should keep leaning after engine rough?

Am I doing anything wrong?

Thanks!

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I roll with RoP for the speed benefits and I still get under 10GPH. O-360 NA. As little as I’m able to fly the fuel savings for LoP isn’t notable plus it’s hard for a carb’d bird to get to LoP.

 

BTW I typically run with 2500 and about 1” under WOT; I’m surprised your fuel burn is greater than mine? I have to do pencil and paper calculations as I don’t have a calibrated fuel flow monitor.

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15 hours ago, FastTex said:

I know there are many posts about leaning but I did not want to hijack any of the other conversations with my specific questions. Plus this is not about LOP vs. ROP.

In the few years I have been flying my Mooney, and after trying to find the proper leaning techniques, I have been following one of the recommendation on this forum to work best for my engine (360-A1A with a JPI830):

8.5GPH LOP

12.5GPH ROP

NEVER 10GPH

And yes, I have been watching the videos about the red box or envelope, whatever you want to call it.

I also have found that my engine likes best the 12.5 setting. All temps, power < 70%, sound, etc. feels nice and smooth.

When OAT is high (about >90F) if I go LOP (8.5GPH) my oil temp goes to 200F or above although my CHTs are always great (350/360). So, I stick with 12.5GPH.

During the last few flights I have been trying to fine tune my leaning technique again. So I do the usual mixture pulling until rough and then add some, to end up at around 10GPH! Even using the JPI procedure. Because 10GPH should be a no-no I push back to 12.5GPH.

Is it ok? Also, how do I go to LOP if, according to the JPI procedure, I should keep leaning after engine rough?

Am I doing anything wrong?

Thanks!

I think what you’re doing wrong is trying to run an NA engine like it’s a turbo. Setting by FF alone is not really optimal. 

I would also say the followIng:

 your engine runs hotter than the one in my F.

Normally CHTs and oil temp track together.

200° is a healthy oil temperature in the summertime.

10gph is a fine mixture setting at certain altitude’s and RPMs.
most IO360s will run 30° LOP smoothly with stock injectors at altitudes where the engine needs to be that lean. How smoothly and how far an engine will run LOP will vary with altitude. I think that most guys who find their engines run rough are over leaning. This is to say that 30° LOP is a fine mixture setting at say 4500 feet but probably not a good choice at 8500 feet. My IO 360 will run beautifully to ~100 LOP at a density altitude of 1000 feet. It will run like absolute shit (if at all) at at that setting at 12,000ft. I don’t care though because that would be a stupid mixture setting for 12,000 feet. Another way of putting this is the more power you can produce, the deeper LOP your engine will run smoothly. If you’re not taking this into consideration it could be causing a problem.

There is no fuel flow ROP or LOP that is optimal at all altitudes and RPMs for a normal aspirated engine.

8.5gph is about 65% anywhere on the lean side of peak. 8.5gph is about 55% power at 100ROP and a smidge more at 50ROP. 

in the summertime it’s fine to lean by CHT. Find the setting on the rich and lean side that yield healthy CHT‘s. Those settings will work in the winter time as well albeit with much colder CHT’s. 
Whether one wants to fly ROP or LOP it’s prudent to focus on engine temps and take whatever fuel flow that yields. 

 

Edited by Shadrach
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9 minutes ago, Shadrach said:

I think what your doing wrong is trying to run an NA engine like it’s a turbo. Setting by FF alone is not really optimal. 

I would also say the followIng:

 your engine runs hotter than the one in my F.

Normally CHTs and oil temp track together.

200° is a healthy oil temperature in the summertime.

10gph is a fine mixture setting at certain altitude’s in RPMs.
most IO360s will run 30° LOP smoothly with stock injectors at altitudes where the engine needs to be that lean. How smoothly and how far an engine will run LOP will vary with altitude. I think that most guys who find their engines run rough are over leaning. This is to say that 30° LOP is a fine mixture setting at say 4500 feet but probably not a good choice at 8500 feet. My IO 360 will run beautifully to ~100 LOP at a density altitude of 1000 feet. It will run like absolute shit (if at all) at at that setting at 12,000ft. I don’t care though because that’s a stupid mixture setting for 12,000 feet. Another way of putting this is the more power you can produce a deeper LOP your engine will run smoothly. If you’re not taking this into consideration could be causing a problem.

There is no fuel flow ROP or LOP that is optimal at all altitudes and RPMs for a normal aspirated engine.

8.5gph is about 65% anywhere on the lean side of peak. 8.5gph is about 55% power at 100ROP and a smidge more at 50ROP. 

in the summertime it’s fine to lean by CHT. Find the setting on the rich and lean side that yield healthy CHT‘s. Those settings will work in the winter time as well albeit with much colder CHT’s. 
Whether one wants to fly ROP or LOP it’s prudent to focus on engine temps and take whatever fuel flow that yields. 

 

Do you mind sharing the mechanics of your leaning for LOP and ROP? 

Thanks!

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2 minutes ago, Shadrach said:

I’m not sure what you’re asking? Are you asking the hows and why’s of my SOP?

I'm asking...how do you lean? Just RPM to 2500, pull mixture, wait for rough engine then richen 50F for ROP or keep leaning for LOP? Or?

I have seen people doing it differently and since we have pretty much the same aircraft... 

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10 minutes ago, FastTex said:

I'm asking...how do you lean? Just RPM to 2500, pull mixture, wait for rough engine then richen 50F for ROP or keep leaning for LOP? Or?

I have seen people doing it differently and since we have pretty much the same aircraft... 

I’ll give you the abbreviated version after I wrap up my morning calls.

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Running greater than 65% LOP requires a bit more work and knowledge do safely..   i just run 100rop between 67-75% and full rich over 75%.  If I feel compelled to run at higher power setting then I’m in go fast mode anyway.

65% and below, lean richest cylinder to peakEGT  

On my io-360-a1a, this is usually means around 22” 2400rpm (46 key number) and 7.8-8.3gph depending on DA   This keeps temps very low   Perhaps too low in the winter

 

 

 

Edited by Browncbr1
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If you want to be able to quickly lean without spending a bunch of time looking at the engine monitor, here are a couple ways to do that:

First, spend some time leaning while using the engine monitor at some of your favorite power settings.  For me that's 2600 RPM and 22" when below about 6500'.  If I'm going higher than that I'm probably going a long way and I'll be up at 8500' or 9500' in which case I'll be 2600 RPM and WOT.  I cruise LOP at all those settings.  For each of those favorite power settings, find out what fuel flow you get.  Do that several times to ensure you are getting consistent numbers.  For me, down low it's about 9.2 to 9.4 GPH.  Up higher it's somewhere between 8.7 to 9.2 GPH.  Once you know what the fuel flow is you can use that knowledge for future flights.  Level off, set the RPM and MP, then pull the mixture to the desired FF.

Second way would be to pull the mixture until you feel a loss of power (not necessarily roughness), then increase the mixture until you feel the power come back.

Personally, if I'm doing a step climb and I'm only going to be level for a few minutes, I'll lean by watching my #1 EGT until it peaks because that is almost always my richest cylinder.  If I'm leveling at my cruise altitude, I'll use the lean find function on my engine monitor.

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@FastTex have you run the Savvy flight test profile to see how well you are able to run lean? It may show one or more of your injectors are not playing nicely with the others.

Here is how I lean my J to get LOP when flying.

After I get to altitude, I let the plane settle into a smooth flight and pull RPM back to my cruise setting (let's say 2,400), pull mixture back to ~11.0 gph and let oil temp and everything settle. Checking I am ~65% or less, I do a quick pull back to about 9.5 gph and set my JPI to Lean Find. After that, it is just dialing out the mixture fairly slowly until the JPI says I am done. I know what combination of MAP/RPM/FF I should get at each altitude, but I like going through the process so I can see if anything is changing with the setting I use. Cues me in to pay closer attention if I see unexpected large changes.

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The quickest and easiest way to set power for a conforming, NA injected engine (that means well balanced F/A ratios) in the summer time, at any altitude, regardless of RPM, is to pull the mixture until slight roughness is encountered then enrichen slightly. Verify the CHT trend,  CHTs should they dropping on all cylinders if transitioning from climb. Enrichen until CHTs begin to rise. Set mixture in the upper end of your CHT comfort zone (I like that hottest at about 335 in the summer).  That will put you somewhere between peak and the lean side of peak and in the ideal mix of cool CHTs, speed and BFSC. In the winter I use 300 as a target on the coldest CHT.  It can be tough to keep it there as my bird will run close to mid 200s on 1 and 4 at mild power settings.

Something to think about. Best BSFC (power per unit of fuel) occurs between Peak (a fine setting depending on altitude) and 50LOP.  The closer to peak the more power you are making.  I lean as close to peak as CHT will allow. 

I do run 100ROP but normally reserve that setting for operations at DAs >10,000'.

That's the short and sweet version.

This post assumes you know your richest and leanest cylinder.  Richest cylinder is used for LOP settings. Leanest Cylinder is used for ROP settings.  

Caveat. While I use CHTs a proxy for engine happiness, I still use EGTs as a measure of the actual power setting.  Hottest cylinder may not be the one you are using for leaning. On my bird #3 is hottest on either side of the mixture spectrum.  This is do to airflow and cowl design, not fuel flow or power.

 

Edited by Shadrach
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1 minute ago, Browncbr1 said:

Running greater than 65% LOP requires a bit more work and knowledge do safely..   i just run 100rop between 67-75% and full rich over 75%.  If I feel compelled to run at higher power setting then I’m in go fast mode anyway.

65% and below, lean richest cylinder to peakEGT  

On my io-360-a1a, this is usually means around 22” 2400rpm (46 key number) and 7.8-8.3gph depending on DA   

 

 

 

If you’re like me and you stay low to stay out of the winds when westbound The fuel savings is significant. Wintertime DAs in my neck of the woods can be as much as 3000 feet below the aircrafts MSL altitude. Winds and complicated airspace in my local often mean 2000-2500 ft is a reasonable choice for trips<150nm 

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M20F, IO360-A1A, JPI930 W/GAMI Injectors.

From the Lycoming manual leaning to EGT ROP (first cylinder to peak), below 75% BHP, run at peak EGT.  See page 3-7 and page 3-8 in attached manual 1.  LEANING TO EXHAUST GAS TEMPERATURE GAGE

A typical cruise for me is 8000 ft with ram air in clear skies, 23" MP, 2350 RPM, 9.1GPH, 150 Kts TAS.

LYCOMING OPERATORS MANUAL O-HO-IO-AIO-HIO-TIO-360.pdf

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Thanks all for the feedback. I even talked on the phone with @airtim (LOL sorry @Shadrach!) for great and valuable info.

One question: when the JPI830 manual says "pre-lean" before pushing the button to activate the lean procedure, does it basically mean to lean the old way (pull to roughness and enrich) and then push the lean finder button?

 

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55 minutes ago, FastTex said:

One question: when the JPI830 manual says "pre-lean" before pushing the button to activate the lean procedure, does it basically mean to lean the old way (pull to roughness and enrich) and then push the lean finder button?

I don't believe so. I think they mean just to not start your Lean Find, from full rich. Rather lean back to a reasonable ROP setting, let everything settle down, then start the Lean Find and let it help you find a good LOP setting.

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39 minutes ago, FastTex said:

when the JPI830 manual says "pre-lean" before pushing the button to activate the lean procedure, does it basically mean to lean the old way (pull to roughness and enrich) and then push the lean finder button?

I think "old way" does the job or use some higher richer FF/lower EGT as first guess, with "pre-lean" & LF the end result is the same as with LF only: just how one can quickly get to peak EGT using LF without crossing it (if EGT = 1000F you have a long way to go with LF only :D if you had 2000ft cruise climb you can just press LF only ;))

There is a disadvantage of using engine roughness for initial guess is when operating at high power (I don't think 1 second of that will kill your engine, it is continuous LOP operation at high power that is problematic) but if you are at low power where you can lean, it should just work for "pre-lean"

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1 hour ago, FastTex said:

One question: when the JPI830 manual says "pre-lean" before pushing the button to activate the lean procedure, does it basically mean to lean the old way (pull to roughness and enrich) and then push the lean finder button?

On 4/21/2020 at 9:02 AM, Oldguy said:

After I get to altitude, I let the plane settle into a smooth flight and pull RPM back to my cruise setting (let's say 2,400), pull mixture back to ~11.0 gph and let oil temp and everything settle.

The pre-lean is what I was describing in my earlier post. Attempting to go LOP immediately after reaching cruise altitude won't get you what you want. Let the plane settle into cruise and get everything to stable operating temperatures with a leaner fuel flow and then start your leaning.

 

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2 hours ago, FastTex said:

Thanks all for the feedback. I even talked on the phone with @Shadrach for great and valuable info.

One question: when the JPI830 manual says "pre-lean" before pushing the button to activate the lean procedure, does it basically mean to lean the old way (pull to roughness and enrich) and then push the lean finder button?

 

I think some wires are crossed here.  I had a nice conversation yesterday with a gentleman in Wisconsin about rebuilding a flap actuator , but no discussions with any one regarding power management.  Happy to talk some time though.

Edited by Shadrach
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1 hour ago, FastTex said:

Thanks all for the feedback. I even talked on the phone with @Shadrach for great and valuable info.

One question: when the JPI830 manual says "pre-lean" before pushing the button to activate the lean procedure, does it basically mean to lean the old way (pull to roughness and enrich) and then push the lean finder button?

 

You'll end up finding a typical fuel flow that is LOP for the power settings you use.  For me that's usually about 9 - 9.4 GPH.  So if I'm going to use the lean find feature, I'll pull the mixture back to about 10.5 GPH and start from there.

You can also use the LF feature starting from the LOP side which is what some people advocate.  To do that, I'd pull the mixture to about 8.5 GPH and then press the button.  I'd then enrichen until I saw the first (not the last) cylinder switch over.  That's because it's actually showing I've gone ROP on that cylinder while all the others are still LOP.  I'd then start leaning again and watch that cylinder go back fewer and fewer degrees below peak.  At some point continuing to lean would start to increase the number of degrees below peak.  I'm now LOP on that cylinder again and I'm done leaning.  To say that another way to hope to reduce confusion, on my engine I might see the #1 cylinder go from 0 to -10 to -15 while I'm enriching.  I'd then lean the mixture and watch it go from -15 to -8 to -2 to -5 to -8 while leaning.  I've now gone from ROP to LOP.

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On 4/21/2020 at 1:32 AM, FastTex said:

 

During the last few flights I have been trying to fine tune my leaning technique again. So I do the usual mixture pulling until rough and then add some, to end up at around 10GPH! Even using the JPI procedure. Because 10GPH should be a no-no I push back to 12.5GPH.

 

What?  Why?  This is something I've never heard.

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1 hour ago, ragedracer1977 said:

What?  Why?  This is something I've never heard.

I do not have the time to research but I'm pretty positive I read it somewhere in here (forum). Nevertheless, glad I brought it up because I'm learning a lot and this week end I will start testing/measuring things paying more attention to temps, etc.

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1 hour ago, Shadrach said:

I think some wires are crossed here.  I had a nice conversation yesterday with a gentleman in Wisconsin about rebuilding a flap actuator , but no discussions with any one regarding power management.  Happy to talk some time though.

Sorry, I corrected it. Wrong copy and paste! ;-)

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Tex,

You have a few details mixed up through the thread from start to finish...

Some things you have glossed over, some you have omitted...

Lots of the details in leaning depend on altitude, and throttle position... and the blue knob too...

Nail down a few variables first, then discuss the finer details of leaning...

Think of it this way for a moment...

Setting the mixture for an IO360...

Where fuel flow can be a range from about 18 to 8 gph... or even less...

Much of this range comes by large motions of the throttle and mixture knob...

But when dialing in the mixture to be 10°F LOP or something like that...

That requires precision... which needs slow rotations of the mixture knob...

So...

1) No... we are not leaning the old style way of going rough, and coming back... (typical method used for a carb)

2) This may not even work for some Mooneys... like a plane with a balanced intake and fuel injectors...

3) doing this... leads to lean until the engine turns off smoothly... :)

4) they probably meant... lean to get into the right neighborhood... or you will be there for hours twisting the mixture knob slowly...

5) if spinning the knob... spinning it quickly gets it in the neighborhood...  call that pre-leaning... 

6) while looking for peak, recognize the lag that occurs when you spin the knob... this is both a function of the system... and the thermocouples themselves... some thermocouples are fast acting... others last forever...

7) When finding peak the right way... it is in one place..

8)  if you go past it, you just come back... by turning the knob slowly the other direction...

9) If it doesn’t make sense... you probably are going too fast with the knob for the system you have...

10) experiment with the MP at 20” or less... this will allow a huge buffer from the red box... while you experiment on the fast way to find peak... altitude or throttle both work..

10.1) having the throttle at WOT... is best for airflow purposes... improves the Gami spread...

11) probably somewhere near 10gph... depending on all the usual variables...

12) Try it with the analog gauge first... it doesn’t get any easier than that...

13) Don’t expect to lean any too much... until you have a good feel for how good your GAMI spread is...

14) How deep you lean, really controls the power and FF...

15) Start with accurately finding peak first... at a set MP, and RPM 

16) Then when you get good at that... take notes...

17) note the first cylinder to peak... and FF it happens at...

18) note the next cylinder... and FF... 

19) repeat for the rest...

20) magically the FF of first - FF of last... is your Gami spread!

Next thing to realize... this setting is only good until you change the MP, or rpm... then a reset is needed...

know this becomes second nature after a while... very easy to do... very repeatable...

PP thoughts only, not a CFI...

Best regards,

-a-

 

 

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