LOP and ROP OPs

[INA201]

I know this will ultimately turn into a dispute on which is better but here goes.  I run LOP probably 70% of the time and ROP the other 30% or so.  I have a JPI 900 and have never really honed the craft of either option.  Generally I will run 80 degrees ROP at full throttle and 2500 RPM as long as CHTs are below 380.  On the LOP side is where I run until the last cylinder to peak is around 10 degrees LOP.  As an aside I can keep leaning during LOP ops way past peak without any real roughness.  What do you guys do? What ROP or LOP level do you prefer? Do you always run the same way or change it up here and there?  Any other input would be greatly appreciated.

 

I have attached this link to revive this thread as an outlet for those that will ultimately go into which is better mode.  

 

[PJClark]

And to pile on--How do you Turbo guys do this? I'm on my second round of GAMIs as of this Wednesday.  GAMI spread still about .7 gph, last to peak can only get to about -10 LOP before I start to get roughness...and TIT is a bit north of 1600, not comfortable that hot.

Hints??? how LOP does one need to get...and will the TIT ever hop over the hump and go LOP also?

[gsxrpilot]

35 minutes ago, PJClark said:

And to pile on--How do you Turbo guys do this? I'm on my second round of GAMIs as of this Wednesday.  GAMI spread still about .7 gph, last to peak can only get to about -10 LOP before I start to get roughness...and TIT is a bit north of 1600, not comfortable that hot.

Hints??? how LOP does one need to get...and will the TIT ever hop over the hump and go LOP also?

You don't just have a turbo, you have a Rocket! My 252 turbo runs very well LOP. My GAMI spread is about .4 and I can get to 20 or 30 degrees lean without any roughness. I hear the Rockets are more difficult to get to run well LOP. The one Rocket pilot that does LOP very well is Lacee @RocketAviator. He's not on this forum much anymore, but maybe the ping will get him to chime in.

I only do LOP at 65% power or less. That way I can actually run right AT peak and the power is low enough that I don't have to worry about harming the engine.

Oh, and my TIT does come down off the peak when I'm LOP. I'm running about 1530 or so TIT and my hot cylinder is usually below 330.

[EricJ]

I have a cylinder that tends to run about 30F colder than the rest, both in EGT and CHT.   When I run LOP the temps generally cool enough that the cold cylinder sometimes gets lead fouling on the bottom (fine wire) plug.   For this reason I don't run LOP as much as I used to and tend to just run ROP unless I have some reason not to, like a very long xc leg where I want to save fuel or something.   I don't get lead fouling when I run 80-100F ROP.

That said, I had similar experiences to you where I could run a long ways LOP and it'd still stay running smoothly, there's just not a lot of reasons to do that.   25-50F LOP gets the benefits of LOP operation, at least on my engine, without getting too crazy or the power dropping off too much.   Just keep an eye on CHTs that they stay high enough for everything to work right, i.e., keep the lead burned off.

[Niko182]

I run lop based on a fuel flow. When im just flying around for fun locally ill pull the power back to like 18 to 20 inches, prop back to 2400, and just lean to like 9 to 10 gph. If it starts running ruff, i just pull the power a bit back til its smooth usually like .3 to .4inches of MP. Climb is always rop. I just keep all the CHTs below 365, which is easy except one cylinder likes to get a little toastier than the rest, sometimes hitting that 365. In cruise, below 8000 ill fly LOP. Above 8000, i fly peak. CHTs have never been a problem with my aircraft so i have that option. Usually around 14 gallons per hour peak at like 10k.

[Rick Junkin]

I'm a bit of an outlier with my Bravo.My focus is on CHT when LOP, while minding that TIT stays below 1650. I run LOP above 10K' at 30/2200, which amounts to a bit less that 70% power at 15-25 LOP and 13.8-14.2 GPH depending on altitude and CHTs. I adjust mixture to get 380 CHT. GAMI spread is 0.4 GPH and took 3 iterations of GAMI injectors to get there across six cylinders. TIT sits at 1590-1600, and sometimes as high as 1625.

EDIT: My bad, I rechecked my power spreadsheet and I'm really at slightly less than 75%. 

 

Cheers,
Rick

[philiplane]

5 hours ago, PJClark said:

And to pile on--How do you Turbo guys do this? I'm on my second round of GAMIs as of this Wednesday.  GAMI spread still about .7 gph, last to peak can only get to about -10 LOP before I start to get roughness...and TIT is a bit north of 1600, not comfortable that hot.

Hints??? how LOP does one need to get...and will the TIT ever hop over the hump and go LOP also?

To run well LOP you need a well maintained ignition system (Bendix mags) with fine wire Tempest spark plugs. Don't bother trying to go further LOP if you have Slick mags and Champion plugs, (either fine wire or massive electrodes), without confirming the mags are perfect, and installing better spark plugs.

[Bob - S50]

At cruise I lean pretty much as INA201.  I lean until the last to peak (usually #1) is just barely LOP.  That's usually 5 - 10 LOP.  The rest will be around 20 - 30 LOP.

From what I've read, if you go much leaner than about 30 -50 LOP you actually start to increase brake specific fuel consumption (become less efficient).  So even if I could lean to 100 LOP I wouldn't do so unless I was fighting to keep my CHT's below 400.  If 30 LOP gave me more power than I wanted I'd probably just pull the throttle back until I had what I wanted.

If I'm level at my cruise altitude I'll usually lean by using the lean find function on our EDM730.  If I'm only leveling for a few minutes during a step climb I'll lean by watching the #1 EGT.  Once I see it peak and start down, that's good enough for me for the couple minutes I'll be at that altitude.

[gacoon]

1 hour ago, Bob - S50 said:

At cruise I lean pretty much as INA201.  I lean until the last to peak (usually #1) is just barely LOP.  That's usually 5 - 10 LOP.  The rest will be around 20 - 30 LOP.

From what I've read, if you go much leaner than about 30 -50 LOP you actually start to increase brake specific fuel consumption (become less efficient).  So even if I could lean to 100 LOP I wouldn't do so unless I was fighting to keep my CHT's below 400.  If 30 LOP gave me more power than I wanted I'd probably just pull the throttle back until I had what I wanted.

If I'm level at my cruise altitude I'll usually lean by using the lean find function on our EDM730.  If I'm only leveling for a few minutes during a step climb I'll lean by watching the #1 EGT.  Once I see it peak and start down, that's good enough for me for the couple minutes I'll be at that altitude.

Thats been my experience with both my current J and my previous one.

[carusoam]

Way to go INA!

It should be safe to go back in the water... discussing OPs... L v. R

Both are acceptable... they get used for different reasons... and different costs...

 

Learn as much as you can...

 

Just learn it is hard to write LOPs... without writing LOP ops....   that would be redundant... !

 

I enjoy using LOP in Cruise below 65%bhp... burns more efficiently, lower temps, cleaner oil...

I use ROP for the climb... leaning using the blue box method... adjusting mixture to stay in the box as I climb...

When leaning, I use primarily FF to get in the range... and complete the effort using the JPI... takes some data gathering at first...

As Bob mentioned there are times to lean roughly... the ships gauge can work here as well... the modern engine monitor shows all the EGTs at once... pick the one that goes past peak last...to watch...

 

Learn to download data, post on the savvy site, and we can discuss the details...

It’s a bit of a science if you like... or it can be pretty rough and still be effective...

Read up on GAMI spreads. Determine what yours is.
 

My Gami spread was a 0.1...

• at low altitudes, it was possible to lean to about 90°F LOP... (deep LOP)
• at higher altitudes, it was possible to lean to about 50°F LOP... (moderate LOP)
• Going LOP at altitudes above 8k’, bhp is <65%bhp, outside the red box, doesn’t gain very much...
• above 8k’, you can choose running right at peak, or slightly LOP, to ensure burning all the fuel to make power...
• Flying deep LOP compresses lots of air that doesn’t get used... if CHTs are in control, compressing excess air doesn’t do very much for your efficiency...

The previous owner of my plane probably spent a lot of dough getting this low Gami spread...   my first attempt to see the Gami spread.... I leaned and leaned waiting for roughness that never occurred.... I leaned slowly until the engine got quiet... then I leaned to have the power return... 

Put a plan together, execute the plan... write down questions... take notes... download data... upload data... share your data...

Start with...

• Verify the rate of data collection... 1 point every second is the best... 6 seconds is the worst...
• Learn about doing run-ups and data collecting at the same time...  
• Read up on balancing your fuel injectors... a quick test your mechanic can help you with... baby food jar test...
• Expect to see things that you didn’t know about your engine...

Not everybody has to go this deep into the technology of flying.... but it is really cool to learn more about how these things work.

This way you can personalize the experience to match your needs...

My desire was to save needing a top OH before TBO... LOP works pretty good for this economic discussion... 

For more fun...

• get everything balanced to a tight Gami spread...
• Collect your data until you are comfortable...
• Set your MP to WOT...
• Adjust mixture as desired, your choice... Flaming dragon mode, or LOP...
• Descend intelligently, keeping an eye on Vne and Vno (based on weight, and atmospheric conditions)
• You can be LOP from the TOC back to the TPA... then, GUMPs GUMPs....
• Remember... doing a GA while LOP because you didn’t use a check list... is bad... bad form, bad for the engine, or it may just quit... 

Are you sure you want to discuss LOP?

Lets talk best power... for T/O at higher altitudes...

same as the blue box technique in the climb....

Having an engine monitor is near magical for the plane owner...

PP thoughts only, not a ,enhancing or CFI...

Let me know if I missed anything, or got something backwards...

If this is TMI, remember... you started it,  

Turbo LOPs... that’s a more fun discussion... make sure to invite all the people that have shared their logic in the past... Turbo LOPs with a Bravo... even more challenging details... 

Best regards,

-a-

[PT20J]

Ross @Shadrach has done a lot of studying and thoughtful experimenting and I think his posts about how he operates a NA engine make a lot of sense and are based on a thorough understanding of the processes involved. Maybe he’d be willing to summarize here.

Skip

[bradp]

I use ROP and LOP as a go fast or go far mentality. 
 

A line of thunderstorms moving towards my destination. ROP.

Want to erk out range or save on my next top off - go far LOP.   

[ArtVandelay]

Other than breaking in the engine, I run LOP in cruise 100% of the time. LOP gives you a better idea of the health of your engine IMHO. There’s a reason why if you’re having engine problems you’re suppose to increase the mixture.

[gsxrpilot]

9 hours ago, bradp said:

I use ROP and LOP as a go fast or go far mentality. 
 

A line of thunderstorms moving towards my destination. ROP.

Want to erk out range or save on my next top off - go far LOP.   

I'm mostly in agreement with @bradp here. My ROP/LOP decision is almost always based on speed. If it's a short single tank trip, ROP is faster. But often LOP means it's a non-stop trip whereas ROP would require a fuel stop. So then it's always LOP.

[jlunseth]

I have a 231. It is a little different from most turbos in several ways.  It does not have a truly “automatic” wastegate controller, I have a Merlyn, but with the Merlyn it is not possible to set an MP, then change the RPM’s and the fuel flow and have the controller maintain the original MP, it doesn’t work that way.  Also, there is an interlink between MP and fuel flow so that changing one also changes the other.  This means there is some fiddling with the knobs to get to a desired degrees lean of peak, and even with a good engine monitor it is not a simple thing to know exactly how far LOP you are running the engine, or each cylinder. Finding peak essentially means, if I set the MP at x and the RPMs at y, and then I change the fuel flow, how far from the peak I have found is my engine running.  But when both MP and FF change then the original peak is no longer valid, you will get a reading on the monitor, but it is a reading of degrees LOP from a peak that no longer exists. 

Nevertheless, I found a way to measure degrees LOP with a fair amount of accuracy.  Over time it became easier just to develop some settings that were “known good,” and to manage the engine by watching the TIT and keeping it at or under 1600.  

LOP or ROP is a fuel/air ratio. It dawned on me that in a turbo engine we have two ways to manage the fuel/air ratio.  One is to lean or enrich the fuel, which an NA operator can do. The other is to add or subtract air, there are limits to that in NA engine operation but for all practical purposes not so with a turbo.  I can add all the air I want, which makes the mixture leaner for a given GPH fuel flow.

My standard setting is 34”, 2450 RPMs, 11.1 GPH.  I went to the Advance Pilot seminar (GAMI) several years ago in Ada, there we learned that, when LOP, percent HP is directly determined by fuel flow and MP is not relevant.  For my engine, percent HP is a constant, 13.7, times the fuel flow, divided by rated HP.  I watch the TIT. On hot days or at high altitudes where cooling is poor I may not be able to control TIT sufficiently, and if I want to maintain cruise power in the 70-75% range I may have to go to ROP ops.

I started doing this when the engine have about 1600 hours (TBO is 1800) thinking, what the heck, I am closing in on an OH anyway, if this does not work it is not a big deal.  But the results have been great, my engine is currently at about 1860 and no plans for an engine OH yet, compressions are really good, I use a quart or less of oil between oil changes.  If I change at 20-25 usually no oil needs to be added in between.  Engine is healthy and runs really well.  The turbo, which works hard with my method, has about 1200 hours on it since it was OHd in 2009.

Cruise speed depends on altitude.  At, say, 10,000, I get around 160-165 kts with these power settings.  

If LOP ops begin to falter, the engine gets a little rough when I lean over, the first thing to check is the spark.  Mags, wires, plugs. That and a good set of GAMI’s is the key to good LOP ops. 

If someone has a different engine type, well, your results may vary, but I would not hesitate to experiment with high MPs as a way of getting to a LOP fuel/air ratio.

[carusoam]

I’m glad JL stopped in...

When it comes to benefits and complexities of running LOP... 

TCs and TNs have more complexity to go with their more benefits...

Following JL’s writing over the years I always learn something.

Wish my memory could hold it all...

Best regards,

-a-

[Shadrach]

On 1/11/2020 at 11:20 AM, PT20J said:

Ross @Shadrach has done a lot of studying and thoughtful experimenting and I think his posts about how he operates a NA engine make a lot of sense and are based on a thorough understanding of the processes involved. Maybe he’d be willing to summarize here.

Skip

Many thanks for the kind words Skip.

This server is loaded with LOP comments from yours truly on how I operate my own engine but I’ll try and give a concise summary.

 I set mixture based on my power needs/wants. I do not have “cookbook numbers”. I think it’s better to understand that all other things being equal, CHT is a proxy for internal cylinder pressure (ICP) as well as detonation margin. The number doesn’t tell you much unless you know what’s behind it.  The <380° CHT that so many quote as their target is fine in July with an OAT of 60-90°F. I would find it concerning in February when the OAT is 10°-sub zero. Better to take into consideration what is driving the temp and what it means regarding ICP.

No matter the regime  I am always thinking about what the ideal CHT would be during that operation. My numbers for summer time are typically 335 to 375°. In the winter I’m leaning to keep CHT’s above  300° but below 345°. I use these ranges because I think they are conservative and give plenty of margin. I am not suggesting they are ideal for everyone.

I use peak EGT (richest cylinder) a lot in cruise when at altitude. It’s a great mixture setting that many don’t consider. It provides an excellent mix of economy and power combined with good detonation margins and clean combustion. In the case of my engine it’s a cooler setting than 100° ROP.  It burns less gas and the speed loss is barely noticeable.

I run ROP if I must fly into strong winds at cruise altitude or for those rare occasions when I’m operating above 12,500.

If I'm operating at a DA below 3000, I’m either full rich or far enough LOP to keep CHTs at a comfortable place with consideration to the OAT.  I live in Maryland and in the dead of winter my 701’ field often has DAs as low as -3000 feet. That puts a lot of gas through the engine at full rich. LOP at low DA is a better option in almost every way. Cooler, cleaner, more efficient and little speed loss.  I use the target EGT method to lean in climb (use mixture to maintain leanest take off EGT until curse altitude is attained).  For cruise I set mixture to yield a CHT that I deem appropriate to OAT..

My engine very much likes high power LOP at low altitude. 25LOP is typically plenty lean to keep CHTs comfortable at most MP settings. On the coldest, high pressure days I start at 40 LOP and fine tune to keep CHTs where I want them. If there are headwinds up high I am happy to fly between 2000-3000’ with the throttle wide open and ram air open at 2500rpm LOP. 

That’s my quick but not so organized summary of the way I run the NA Lyc IO360. Posted from iPhone so bare with me.

Edited January 14, 2020 by Shadrach

[jlunseth]

On 1/13/2020 at 3:28 AM, carusoam said:

 

Wish my memory could hold it all...

Best regards,

-a-

Me too.

[jlunseth]

On 1/10/2020 at 2:56 PM, PJClark said:

And to pile on--How do you Turbo guys do this? I'm on my second round of GAMIs as of this Wednesday.  GAMI spread still about .7 gph, last to peak can only get to about -10 LOP before I start to get roughness...and TIT is a bit north of 1600, not comfortable that hot.

Hints??? how LOP does one need to get...and will the TIT ever hop over the hump and go LOP also?

You should keep trying until you get the GAMI spread down below .5, but I would look into the mags and plugs, that may solve your roughness.  Think of it this way, the air/fuel mix has less available fuel to ignite when LOP than at peak or when ROP.  Rebuilding, or just cleaning and checking timing on the mags solves the problem a good part of the time.  Clean plugs help alot.  The connections need to be checked for any sign of corrosion or arcing and cleaned.  

The EGTs are hotter at a LOP setting than at an equivalent ROP setting, which means the TIT will be hotter.  It is just mathematical.  If we say, hypothetically, that peak EGT is 1500, settings of 25 degrees LOP and 125 degrees ROP might be equal at 70-some percent HP.  The EGT for the LOP setting will be about 100 dF hotter than the ROP just by the math.  I would not be concerned about TIT at or slightly over 1600 and in fact that is where mine is during the summer months.  When the TIT starts moving over 1600 I do something about it, "something" generally means leaning out a little further, in other words going further LOP.  The TIT does go "over the hump" and start coming down.  Since power is directly related to fuel flow, that means you will be making a little less power and will go a little slower.  If it becomes a situation where the TIT is just going over 1600 no matter what I do, then it is ROP time, and that happens in my engine at somewhere in the mid-teens in the summer.  I would check your POH on this, but I am pretty sure it will say that the TIT redline for continuous use is 1650 or higher.  You should be able to let it run at 1600, I have done that quite a bit with the turbo on my 231 and as I mentioned above, I am at 1200 since turbo overhaul.  I am going to have it overhauled again at annual time this year I think, but it is just a precaution, I am not having any issues with it.  It is more a matter of being curious about what they will see when they tear it down, in light of all the LOP OPS on it now.

Edited January 16, 2020 by jlunseth

[gsxrpilot]

On the whole, LOP opps in a turbo is easier than with a NA engine. With the turbo there is no leaning in the climb. 

When I attended the APS course at GAMI, they drew the whole procedure from takeoff at full rich, the climb, level off and set cruise, then go to LOP, and set for lean cruise. This was all for the NA guys. I put up my hand and asked, if they would do the same diagram for turbo engines. George said sure, and erased everything between the initial takeoff settings and the LOP cruise setting. "There is the turbo procedure."

1. Take off - everything full forward.
2. Level off at final cruise altitude - set power, set prop, pull mixture back to LOP setting based on fuel flow.

That's the whole procedure.

[PT20J]

I think LOP is a lot more useful in a turbo, certainly out west where the MEAs are high and the power output from a NA engine is already so low that LOP just makes it go slow especially with only 200 HP. It’s useful down low when not in a hurry. Or, if you have one of the BIG engine models, you can think of it as derating. You go slower, but you mpg goes up and it’s not a bad tradeoff.

Skip

[Shadrach]

14 hours ago, PT20J said:

I think LOP is a lot more useful in a turbo, certainly out west where the MEAs are high and the power output from a NA engine is already so low that LOP just makes it go slow especially with only 200 HP. It’s useful down low when not in a hurry. Or, if you have one of the BIG engine models, you can think of it as derating. You go slower, but you mpg goes up and it’s not a bad tradeoff.

Skip

My stock F will do 150kts or better at <2500ft DAs on the lean side of peak.  I have seen better than 150kts into a light headwind under certain conditions. Low alt LOP is a useful tool when westbound and the winds at altitude are strong. Do keep in mind a 200hp IO360 can easily and safely be operated at ~80%hp or more at low altitude in the winter months. Especially with ram air. I get 1-1.25” down low. Under those conditions, opening the ram air will yield a 30-50° EGT drop when on the lean side peak.

I’m happy to take any skeptics for a ride.

Edited January 17, 2020 by Shadrach

[CoffeeCan]

Guys, I'm very appreciative of all the info y'all are putting out, but I'm still pretty damn confused. 

Here's my deal. I fly a 1986 M20K with aftermarket intercooler and Merlyn wastegate and GAMIjectors. I also run a JPI 730 engine monitor. My engine has only about 320 hours since overhaul and it runs very consistently across all 6 cylinders according to my observations of my JPI. CHT's are typically within 20-25 dF at cruise, EGT's are also in about the same variability range. 

I started flying my aircraft using the basic settings my initial Mooney CFI (David McGee at All American) recommended: 30" M.P. 2500 RPM, and FF of about 12-13 GPH. Over the first 6 months of flying it I searched high and low for more precise engine power settings for given altitudes, eventually drew up a chart based on the M252 performance tables... which meant I was running about 40-50 dF ROP in cruise, which is where lots of folks say the TSIO-360-LB is happiest. Which is OK, except when I wanted to fly a long ways and fuel costs/range became more of a factor... so over the past while I've been playing with LOP ops. 

Now, the MAPAlog article at Mooneypilots.com says this:  "Here's what I tell MAPA members who have an intercooler installed on their 231 - find aT M20K 252 power chart and use it for your engine.  Takeoff and climb your intercooled  231 at 36" manifold pressure, 2700 RPM and 1400 degrees TIT.  Cruise that same airplane at the power setting we designed the 252 to be cruised at, which is  28" manifold pressure, 2500 RPM, Peak TIT plus 50 degrees rich.  Use these settings and your intercooled 231 will be a happy camper and a good performer."

... but most of what I have been reading and watching on YouTube tells me that running LOP has a lot of engine longevity benefits in addition to the fuel economy benefits. So I've been trying to apply a lot of what I've been reading to my own flights, and here's what I've figured out so far. I ain't an engineer, and my ego ain't involved here... I just want to fly my bird as sensibly and efficiently as I can to the next overhaul, hopefully after another 1800 hours. So if y'all have some good advice that I can understand, I'd appreciate it. 

1. The POH and the GAMI AFM Supplement both say I should use TIT for leaning procedures, not CHT, not EGT... so that's what I've been using. Maximum sustained operating temp is 1650, but I've rarely reached that, let alone exceeded it. I'm open to using CHT or EGT, though, if that's what seasoned pilots recommend doing... but tell me why, please, as I'm loath to disregard both the POH and the GAMI AFM

2. I've found my airplane likes thin air. I get better cruise speed and economy if I'm up in the teens, so if I'm flying farther than a hundred dollar hamburger run, and the winds aren't really unfavorable, I climb up into the 12,000' - 17,000' range for better KTAS and fuel flow. Running ROP, fuel flows at 75% (estimated) power are in the 11.5-13.5 GPH range. At 65% (estimated) power, running 30 degrees lean of peak TIT, I'm burning 8.8-9.5 GPH. Power drops somewhat, but a loss of 6-8 KTAS is more than made up for by the increased range. F'rinstance, if I fly at 75% power and 40 dF ROP, I have to stop in Arkansas to take on fuel on my way to Wisconsin to see the grandkids. If I run at 65% power and LOP, I can fly from Milwaukee to south Texas without a fuel stop and with a healthy fuel reserve on landing. (Note: FF's are read from my panel FF meter, my JPI does not have a FF readout.) (Also note: I say "estimated" power, as I'm using M252 power settings data due to the installation of aftermarket intercooler and wastegate.)

3. I've been reluctant to run LOP at any power settings above 65%, based on opinions I've read here and there... but now I'm wondering if this is nonsense, or prudence? I'd appreciate some input  on this. 

4. I have not explored downloading my JPI data into the app y'all seem to all know about... can someone enlighten me?

 

 

 

[gsxrpilot]

1 hour ago, CoffeeCan said:

Guys, I'm very appreciative of all the info y'all are putting out, but I'm still pretty damn confused. 

Here's my deal. I fly a 1986 M20K with aftermarket intercooler and Merlyn wastegate and GAMIjectors. I also run a JPI 730 engine monitor. My engine has only about 320 hours since overhaul and it runs very consistently across all 6 cylinders according to my observations of my JPI. CHT's are typically within 20-25 dF at cruise, EGT's are also in about the same variability range. 

I started flying my aircraft using the basic settings my initial Mooney CFI (David McGee at All American) recommended: 30" M.P. 2500 RPM, and FF of about 12-13 GPH. Over the first 6 months of flying it I searched high and low for more precise engine power settings for given altitudes, eventually drew up a chart based on the M252 performance tables... which meant I was running about 40-50 dF ROP in cruise, which is where lots of folks say the TSIO-360-LB is happiest. Which is OK, except when I wanted to fly a long ways and fuel costs/range became more of a factor... so over the past while I've been playing with LOP ops. 

Now, the MAPAlog article at Mooneypilots.com says this:  "Here's what I tell MAPA members who have an intercooler installed on their 231 - find aT M20K 252 power chart and use it for your engine.  Takeoff and climb your intercooled  231 at 36" manifold pressure, 2700 RPM and 1400 degrees TIT.  Cruise that same airplane at the power setting we designed the 252 to be cruised at, which is  28" manifold pressure, 2500 RPM, Peak TIT plus 50 degrees rich.  Use these settings and your intercooled 231 will be a happy camper and a good performer."

... but most of what I have been reading and watching on YouTube tells me that running LOP has a lot of engine longevity benefits in addition to the fuel economy benefits. So I've been trying to apply a lot of what I've been reading to my own flights, and here's what I've figured out so far. I ain't an engineer, and my ego ain't involved here... I just want to fly my bird as sensibly and efficiently as I can to the next overhaul, hopefully after another 1800 hours. So if y'all have some good advice that I can understand, I'd appreciate it. 

1. The POH and the GAMI AFM Supplement both say I should use TIT for leaning procedures, not CHT, not EGT... so that's what I've been using. Maximum sustained operating temp is 1650, but I've rarely reached that, let alone exceeded it. I'm open to using CHT or EGT, though, if that's what seasoned pilots recommend doing... but tell me why, please, as I'm loath to disregard both the POH and the GAMI AFM

2. I've found my airplane likes thin air. I get better cruise speed and economy if I'm up in the teens, so if I'm flying farther than a hundred dollar hamburger run, and the winds aren't really unfavorable, I climb up into the 12,000' - 17,000' range for better KTAS and fuel flow. Running ROP, fuel flows at 75% (estimated) power are in the 11.5-13.5 GPH range. At 65% (estimated) power, running 30 degrees lean of peak TIT, I'm burning 8.8-9.5 GPH. Power drops somewhat, but a loss of 6-8 KTAS is more than made up for by the increased range. F'rinstance, if I fly at 75% power and 40 dF ROP, I have to stop in Arkansas to take on fuel on my way to Wisconsin to see the grandkids. If I run at 65% power and LOP, I can fly from Milwaukee to south Texas without a fuel stop and with a healthy fuel reserve on landing. (Note: FF's are read from my panel FF meter, my JPI does not have a FF readout.) (Also note: I say "estimated" power, as I'm using M252 power settings data due to the installation of aftermarket intercooler and wastegate.)

3. I've been reluctant to run LOP at any power settings above 65%, based on opinions I've read here and there... but now I'm wondering if this is nonsense, or prudence? I'd appreciate some input  on this. 

4. I have not explored downloading my JPI data into the app y'all seem to all know about... can someone enlighten me?

 

 

 

Sending you a PM.

[Niko182]

1 hour ago, CoffeeCan said:

Guys, I'm very appreciative of all the info y'all are putting out, but I'm still pretty damn confused. 

Here's my deal. I fly a 1986 M20K with aftermarket intercooler and Merlyn wastegate and GAMIjectors. I also run a JPI 730 engine monitor. My engine has only about 320 hours since overhaul and it runs very consistently across all 6 cylinders according to my observations of my JPI. CHT's are typically within 20-25 dF at cruise, EGT's are also in about the same variability range. 

I started flying my aircraft using the basic settings my initial Mooney CFI (David McGee at All American) recommended: 30" M.P. 2500 RPM, and FF of about 12-13 GPH. Over the first 6 months of flying it I searched high and low for more precise engine power settings for given altitudes, eventually drew up a chart based on the M252 performance tables... which meant I was running about 40-50 dF ROP in cruise, which is where lots of folks say the TSIO-360-LB is happiest. Which is OK, except when I wanted to fly a long ways and fuel costs/range became more of a factor... so over the past while I've been playing with LOP ops. 

Now, the MAPAlog article at Mooneypilots.com says this:  "Here's what I tell MAPA members who have an intercooler installed on their 231 - find aT M20K 252 power chart and use it for your engine.  Takeoff and climb your intercooled  231 at 36" manifold pressure, 2700 RPM and 1400 degrees TIT.  Cruise that same airplane at the power setting we designed the 252 to be cruised at, which is  28" manifold pressure, 2500 RPM, Peak TIT plus 50 degrees rich.  Use these settings and your intercooled 231 will be a happy camper and a good performer."

... but most of what I have been reading and watching on YouTube tells me that running LOP has a lot of engine longevity benefits in addition to the fuel economy benefits. So I've been trying to apply a lot of what I've been reading to my own flights, and here's what I've figured out so far. I ain't an engineer, and my ego ain't involved here... I just want to fly my bird as sensibly and efficiently as I can to the next overhaul, hopefully after another 1800 hours. So if y'all have some good advice that I can understand, I'd appreciate it. 

1. The POH and the GAMI AFM Supplement both say I should use TIT for leaning procedures, not CHT, not EGT... so that's what I've been using. Maximum sustained operating temp is 1650, but I've rarely reached that, let alone exceeded it. I'm open to using CHT or EGT, though, if that's what seasoned pilots recommend doing... but tell me why, please, as I'm loath to disregard both the POH and the GAMI AFM

2. I've found my airplane likes thin air. I get better cruise speed and economy if I'm up in the teens, so if I'm flying farther than a hundred dollar hamburger run, and the winds aren't really unfavorable, I climb up into the 12,000' - 17,000' range for better KTAS and fuel flow. Running ROP, fuel flows at 75% (estimated) power are in the 11.5-13.5 GPH range. At 65% (estimated) power, running 30 degrees lean of peak TIT, I'm burning 8.8-9.5 GPH. Power drops somewhat, but a loss of 6-8 KTAS is more than made up for by the increased range. F'rinstance, if I fly at 75% power and 40 dF ROP, I have to stop in Arkansas to take on fuel on my way to Wisconsin to see the grandkids. If I run at 65% power and LOP, I can fly from Milwaukee to south Texas without a fuel stop and with a healthy fuel reserve on landing. (Note: FF's are read from my panel FF meter, my JPI does not have a FF readout.) (Also note: I say "estimated" power, as I'm using M252 power settings data due to the installation of aftermarket intercooler and wastegate.)

3. I've been reluctant to run LOP at any power settings above 65%, based on opinions I've read here and there... but now I'm wondering if this is nonsense, or prudence? I'd appreciate some input  on this. 

4. I have not explored downloading my JPI data into the app y'all seem to all know about... can someone enlighten me?

 

 

 

From what ive heard, 40 to 50 rop is the worst place for an engine to be.