Leaning Best Practice for newbie

[Jesse23]

Probably my 1st post.  Started flying 1980 M20J and know the topic has been well discussed here.  I am looking at this broadly, just to get on the right side as I gain experience in these beautiful birds.  2 flights as co-pilot to get a feel and get familiar with cockpit.  At cruise 2400/24 MP @ 8.4/8.6 GPH, which I think is pretty good for 200 HP IO360-A2B6D according to the JPI.  I was looking at the POH and Lycoming.  At 75% or less POH states 14C/57F ROP, std temp.  Lycoming states to use peak EGT for same power settings.  Being a former machinist, those are not close enough for me.

I'd like to be more precise, but getting stared, can I just use the JPI and keep CHT @350-375 with GPH numbers for leaning and use economy cruise at 75%?  I am not a speed demon yet.  I have 3-4 landings and the sight picture is much better for me coming from a high wing.  And Don Kaye's video was a big help as was my CFI coaching me on speed coming in.

I have seen a wealth of valuable information here.

[201er]

How the heck did you come up with 2400/24?

Just go WOT anywhere above 3000ft, 2500RPM, and bring the mixture back to 8-8.5GPH and you'll be golden. If you want more power, then you'll have to learn a thing or two about engine management, detonation, and leaning.

[Oldguy]

Welcome aboard, Jesse! Fill out your avatar so we can get to know you better.

Do a search for "red box" or "red fin" (areas to avoid) for some additional information. Also, you can look for Savvy Aviation and Mike Busch to get even more information on running your engine. If you can download the information from your JPI, Savvy has a free service where you can upload it to their web site and see graphically how your engine is performing. It would be at www.savvyanalysis.com. 

Several discussions on here concerning the POH numbers being somewhat off for engine longevity, depending on best power or economy cruise choice.

 

[Jesse23]

Thanks for the responses.  I forgot to mention the 2400/24 MP was @ 2,000'.  I did read some earlier posts about the POH not so correct on this topic.

[gsxrpilot]

As @Oldguy suggested, add some in formation to your profile so we can help you better. If you'll list your location, either city or airport, I can add you to the MooneySpace Map. You might find you live close to one of the experienced members on this forum who could show you how we fine tune these special airplanes for max speed, max range, and max hours from our engines. 

[Jesse23]

Thanks gsxrpilot.  I have read many of your posts.  Go easy on me, I'm a rookie. I updated my profile.  X39 is Tampa North, just SE of KBKV Brooksville.

[Shadrach]

2 hours ago, Jesse23 said:

Probably my 1st post.  Started flying 1980 M20J and know the topic has been well discussed here.  I am looking at this broadly, just to get on the right side as I gain experience in these beautiful birds.  2 flights as co-pilot to get a feel and get familiar with cockpit.  At cruise 2400/24 MP @ 8.4/8.6 GPH, which I think is pretty good for 200 HP IO360-A2B6D according to the JPI.  I was looking at the POH and Lycoming.  At 75% or less POH states 14C/57F ROP, std temp.  Lycoming states to use peak EGT for same power settings.  Being a former machinist, those are not close enough for me.

I'd like to be more precise, but getting stared, can I just use the JPI and keep CHT @350-375 with GPH numbers for leaning and use economy cruise at 75%?  I am not a speed demon yet.  I have 3-4 landings and the sight picture is much better for me coming from a high wing.  And Don Kaye's video was a big help as was my CFI coaching me on speed coming in.

I have seen a wealth of valuable information here.

Welcome Jesse,

Congratulations on your new to you M20J. If you're looking for precision, I would say the POH is not a great reference.  Especially for the year and model of your machine.  Does your POH look like the attached table? Who sets their engine at 23.2inHg or 25.8inHg?  In addition to being ridiculous, it's likely inaccurate and not repeatable in practice.  If you want precision, you'll need to develop your own data.  The truth is we never really know the actual power being made. The POH charts are needlessly complicated and require looking at a separate table to determine book speed which is likely inaccurate anyway.  Short of a dyno run, power is an estimate (even with a fancy $5000 engine monitor) that probably get's close +/- a few percent.  It is easier to calculate power on the lean side of peak, but it's still an estimate.

 It would be a more useful exercise to familiarize yourself with how these engines run, their shortcomings, what settings are most gentle, what settings are most aggressive and the pros and cons of of settings across the spectrum. The goal is to know the how speed, fuel burn and engine temps are related and how to set the engine to get closest to the desired goal. The POH charts are needlessly complicated and require looking at a separate table to determine book speed per which is likely inaccurate any way.

I tell everyone to start with these columns written by John Deakin.  John is a continental guy, but the concepts are applicable to any fixed timing, air-cooled aeroengine.  Most of the folks on this forum have read them. These columns have likely been one of the greatest influence on the current thinking regarding recip engine management.

Pelican's Perch #63:Where Should I Run My Engine? (Part 1)

Pelican's Perch #64:Where Should I Run My Engine? (Part 2 -- The Climb)

Pelican's Perch #65:Where Should I Run My Engine? (Part 3 -- Cruise)

Pelican's Perch #66:Where Should I Run My Engine? (Part 4 -- Descent)

 

 

[Bob - S50]

Another good source (I learned the most from it) is John Deakin and his Pelican's Perch.  Go to this page:

Pelican's Perch

A good start would be to look at articles 18, 19, 43, and 63-66.  Keep in mind that his articles are geared around a 6 cylinder Continental engine in his Bonanza so some of his suggestions are slightly different (like hot starts) than they will be for your engine.

 

[FastTex]

1 hour ago, gsxrpilot said:

As @Oldguy suggested, add some in formation to your profile so we can help you better. If you'll list your location, either city or airport, I can add you to the MooneySpace Map. You might find you live close to one of the experienced members on this forum who could show you how we fine tune these special airplanes for max speed, max range, and max hours from our engines. 

Anyone near KAND (Anderson SC)? I think I need that kind of help. 2400/24 is what I was told in cruise (I believe the POH also mentions that) and 26/2600 during climb. I have listened the red fin stuff, LOP vs, ROP but I’m still kind of afraid to pull the mixture too much when I fly with the Mooney.

[Jesse23]

Great info Shadrach and Bob.  Yep. that's what my POH looks like.  I think I get the hint.  2400/24 is @ %65 power at 2K' with 10/C correction. +.4 MP.  I have some homework and flying to do.

[1964-M20E]

LOP vs ROP is a argument we have had many times here.  However, above 3000 feet use WOT, 2500 to 2600 RPM and lean to your desired temp ROP or LOP.  Unless you are just boring holes in the sky then you can throttle back to your desired power setting.

Climb using WOT, 2700RPM and begin leaning as you get above 3000 feet watch the EGTs and CHTs keeping the CHTs below 400F.

 

You won't necessarily kill and engine running it in the red box but for long term you may cause certain parts to have shorter useful lives.

[gsxrpilot]

Welcome aboard and check your PM's for a link to the map.

With a N/A engine... there is a pretty simple way to learn. Just go high enough. Obviously you've noticed that as you climb, with the throttle wide open, your MP decreases. Just climb until you reach a point where your MP + RPM = 65% power or less. Now that you're there, leave the throttle alone, set your RPM to your liking (2500 is fine), and then play around with the mixture until you get comfortable with it. You can't hurt your engine no matter what you do with the mixture at that power setting. So pull it back, see how low you can get the fuel flow without it feeling like it's running on two cylinders. Watch your CHT's to keep them below 400 or 380 even better. But you should notice that the more you reduce the mixture, the cooler they get.

Once you figure out the fuel flow, you'll know where to put the mixture all the time. You also might discover that your Mooney will go a lot longer in the air than your bladder can. Queue @Piloto 

[Shadrach]

16 minutes ago, Jesse23 said:

Great info Shadrach and Bob.  Yep. that's what my POH looks like.  I think I get the hint.  2400/24 is @ %65 power at 2K' with 10/C correction. +.4 MP.  I have some homework and flying to do.

The altitude listed in the POH is not part of the computation. 2400/24 at 59df is 65% regardless of the altitude that those numbers are attained. The engine does not care about DA when it's throttled back to 24' because the throttle is limiting MP not the DA.

24' is 24' is 24' all other things being equal.

Edited October 24, 2018 by Shadrach

[Marauder]

Great info Shadrach and Bob.  Yep. that's what my POH looks like.  I think I get the hint.  2400/24 is @ %65 power at 2K' with 10/C correction. +.4 MP.  I have some homework and flying to do.

I would also check the accuracy of your fuel flow on your JPI. The transducer adjustment procedure is in the manual. Pretty straightforward, fill up, fly, check usage against reported usage provided by the JPI, adjust if needed.


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[jaylw314]

If your still getting familiar, I'd suggest:

Climb -- full rich

Cruise -- up to 2500/25", lean to just before the onset of roughness.  You're below 70% power and Lycoming says you can lean to anything below that.  It's simple, you don't have to look at the gauges, and you can focus on doing other stuff while you're learning the plane.  Later on, you can muck about with experimenting with finding peak EGT and other stuff

[Oldguy]

46 minutes ago, Jesse23 said:

Thanks gsxrpilot.  I have read many of your posts.  Go easy on me, I'm a rookie. I updated my profile.  X39 is Tampa North, just SE of KBKV Brooksville.

One thing you might consider is attending the Mooney Safety Foundation Pilot Proficiency Program (PPP) in Lakeland Feb. 1-3, 2019. You will get a lot of flying knowledge about your new-to-you Mooney as well as tons of education on systems, speeds and feeds, and configuration management specific to your model Mooney. Not to mention it will likely attract many Mooney pilots, as it always does.

[Shadrach]

Since we're making recommendations, I'll mention that the angle valve intake is tuned to distribute air as evenly as possible at wide open throttle (WOT). cocking the throttle butterfly likely negates some of that tunning.  Air is free so why not use as much as you can?  My engine remains at WOT from take off until I start planning pattern entry at my destination.  I use mixture and RPM to effect changes to FF, CHT and NVH.

Edited October 25, 2018 by Shadrach

[201er]

34 minutes ago, Shadrach said:

The altitude listed in the POH is not part of the computation. 2400/24 at 59df is 65% regardless of the altitude that those numbers are attained. The engine does not care about DA when it's throttled back to 24' because the throttle is limiting MP not the DA.

24' is 24' is 24' all other things being equal.

Not with varying humidity

[Shadrach]

1 hour ago, 201er said:

Not with varying humidity

Let me just restate a sentence from my post in a more obvious way.    ALL OTHER THINGS BEING EQUAL.  

Heres the latin if that helps... Ceteris paribus 

What's the humidity on a standard day?

Edited October 24, 2018 by Shadrach

[DualRatedFlyer]

1 hour ago, gsxrpilot said:

Welcome aboard and check your PM's for a link to the map.

With a N/A engine... there is a pretty simple way to learn. Just go high enough. Obviously you've noticed that as you climb, with the throttle wide open, your MP decreases. Just climb until you reach a point where your MP + RPM = 65% power or less. Now that you're there, leave the throttle alone, set your RPM to your liking (2500 is fine), and then play around with the mixture until you get comfortable with it. You can't hurt your engine no matter what you do with the mixture at that power setting. So pull it back, see how low you can get the fuel flow without it feeling like it's running on two cylinders. Watch your CHT's to keep them below 400 or 380 even better. But you should notice that the more you reduce the mixture, the cooler they get.

Once you figure out the fuel flow, you'll know where to put the mixture all the time. You also might discover that your Mooney will go a lot longer in the air than your bladder can. Queue @Piloto 

why 65%?

[Andy95W]

5 minutes ago, DualRatedFlyer said:

why 65%?

That's the %HP that experts like John Deakin, Mike Busch, and the folks at GAMI say that excessive leaning won't cause detonation, knocking, or engine damage.

[Hank]

5 minutes ago, DualRatedFlyer said:

why 65%?

Because it's low enough power to avoid the Red Box, but still enough to make good speed. Search and find the chart . . . Should be in one or more of the referenced Pelican articles.

DO NOT search MooneySpace for LOP, unless you have hours to kill!!

SECOND on the MAPA PPP. The sooner you go, the less bad habits you will have to unlearn. They will teach you how to manage your engine properly, what speeds to use when. My first was a mere 5 weeks after I finished my insurance dual, and I'm still flying like they taught and applying the lessons learned. See www.mooneypilots.com for details.

[Shadrach]

4 minutes ago, DualRatedFlyer said:

why 65%?

Because that is the theoretical power level at which the engine becomes immune to aggressive mixture settings.  If you've heard or read the term "Red Box" it refers to an area on the mixture spectrum that generates the highest peak cylinder pressures. That "Red Box" expands and contracts at different manifold pressures. As you climb MP drops and the "Red Box" narrows. At an altitude with a DA that will not allow more than 65%, the "Red Box" disappears and you can set the mixture anywhere on the spectrum.

[Shadrach]

Well now that that's been covered...

[jaylw314]

50 minutes ago, DualRatedFlyer said:

why 65%?

I'd also point out that's where Continental says you can lean to your heart's content, whereas Lycoming says you can do so below 70%.  I think I remember that from one of Deakin's articles