LOP Video

Popcorn

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As someone who has tuned turbocharged cars making a good deal of power, I like this video.
 
As someone who flies an airplane with carburetors and without an engine monitor, I've no dog in this hunt.
 
Well done video explaining LOP/ROP for normally aspirated fuel injected engines. He sums up everything I’ve come to learn about the basics. Even though he flies a less than superior plane ;)
 
Its a good video and has good information. He made a mistake in his calculations at the end though. He didn't account for the fact that running LOP will cause him to fly for longer time. He assumed he would fly the same amount of time both ROP and LOP. Well, dont forget, when you go LOP, you are reducing power. Yes you are getting better mpg. But you should compare it to the mpg you get running ROP at the same airspeed. Still, you do save fuel and money running LOP. More than you would running ROP at the same airspeed. But thats not how he calculated it.
 
#ilikepie and i like pie bookmarking
 
Radar Contact said:
Well done video explaining LOP/ROP for normally aspirated fuel injected engines. He sums up everything I’ve come to learn about the basics. Even though he flies a less than superior plane ;)
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You must have watched the wrong video.
 
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coloradobluesky said:
Its a good video and has good information. He made a mistake in his calculations at the end though. He didn't account for the fact that running LOP will cause him to fly for longer time. He assumed he would fly the same amount of time both ROP and LOP. Well, dont forget, when you go LOP, you are reducing power. Yes you are getting better mpg. But you should compare it to the mpg you get running ROP at the same airspeed. Still, you do save fuel and money running LOP. More than you would running ROP at the same airspeed. But thats not how he calculated it.
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....but he did base his cost saving on time of "life of engine" 2000hr TBO - so the savings were true for the TIME he used. Granted, he would've flown more distance in that time at higher KIAS. He could have done a calculation based on his MPG figures (which I guess you/I could if so inclined - in which I don't care to invest the time)
 
so, like I've been saying, BO!


any video that has the outtakes in it is ok in my book!
 
When you're flying a Bo, saving a little fuel should be pretty low on the list of priorities. The whole idea of having a faster plane is to use its speed to get to a destination more quickly! :D

My simplified version of leaning (this is with an injected engine and fixed-pitch prop)...maintain my takeoff EGT as I climb for safe ROP operation, typically around 1250 degrees. This, for a typical 50-mile breakfast run, say, at 5500 feet and 2350-2400 rpm. No need to press the speed on shorter flights...I actually want them to last longer just for the enjoyment of being airborne. :)

For a longer trip, I'm always above 8000' DA, where the engine is making 75 percent power or less and I can't hurt the engine no matter what I do with the mixture knob. Here, I just set speed by leaning to a particular fuel flow: 7.0 gph economy cruise (almost never) or 8.0 gph performance cruise (yeah, that's the ticket!). Don't really care where the rpm lands, as long as it's under 2750.

At performance cruise I shoot for 400 degrees CHT max on the hottest cylinder; if it inches up to 401, I lean the mixture just a tiny bit until I see the CHT drop.

I can't stand LOP operation where the engine runs rough!
 
How do you TN guys go LOP?
Isn't the red box usually huge unless you go way up?
 
My A65's Stromberg carb has "auto lean." lol

I may invest in some analog CHT gauges one of these days, just for kicks. I'd go digital, but, you know, no electrical system. :eek:

I did enjoy the video, however. Might be useful information if ever I get into a "complex" airplane (i.e. one with a mixture knob).
 
With my altitudes and mission I don't often go LOP, but that was a very good video.
 
My question about his technique, is which cylinder does he pick to determine when "peak" is achieved. If he chooses the leanest cylinder, it will reach peak before the other cylinders and only some of his cylinders will be LOP. (disclaimer, I didn't watch till the end).
 
JOhnH said:
My question about his technique, is which cylinder does he pick to determine when "peak" is achieved. If he chooses the leanest cylinder, it will reach peak before the other cylinders and only some of his cylinders will be LOP. (disclaimer, I didn't watch till the end).
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Watch til the end.
 
Also to note with the JPI you can use the lean find mode to dial in your ROP/LOP temps exactly. In that mode it will automatically identify the first cylinder to peak. It will store that value you and you can adjust rich or lean from there and it will tell you how many degrees from peak you are.
 
JOhnH said:
My question about his technique, is which cylinder does he pick to determine when "peak" is achieved. If he chooses the leanest cylinder, it will reach peak before the other cylinders and only some of his cylinders will be LOP. (disclaimer, I didn't watch till the end).
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He's shortcutting.

The JPI EDM he is equipped with has a Lean Find-LOP function which will identify the leanest cylinder as you lean and the richest once you are on the LOP side. One of Martin's points is, once you identify the "proper" cylinder in your airplane, it doesn't change. So, basically, he bypasses the Lean Find function, Steps to his known leaning cylinder, and leans the system based on it.
 
JOhnH said:
ok. But I really prefer written articles to videos. I can skim an article to find what I i am looking for.
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It's also easier to miss things by skimming past an important point you didn't think was important.
 
One thing he didn’t say is one of the reasons that one of the times when it makes sense to run ROP is during the climb: If you forget to touch the mixture knob while increasing altitude, the mixture will enrichen on its own due to the air thinning out. If you are ROP, it will stay ROP. If you are LOP, it will edge richer right into the red box, which is large because you are probably climbing at more than 65% power.

But this was a nicely done video on the topic. I’m thankful for people like that who take the time to make a quality video about flying or anything else I want to learn about. Maybe someday I’ll find a good informative video that teaches how to make good informative videos so I can give back a little with the things I know how to do. (Like making parodies of everyday situations and bad puns.)
 
midlifeflyer said:
He's shortcutting.

The JPI EDM he is equipped with has a Lean Find-LOP function which will identify the leanest cylinder as you lean and the richest once you are on the LOP side. One of Martin's points is, once you identify the "proper" cylinder in your airplane, it doesn't change. So, basically, he bypasses the Lean Find function, Steps to his known leaning cylinder, and leans the system based on it.
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Yep. Some models (mine, for instance, an EDM-700) can only lean-find from the ROP side so it's not as useful for LOP. I don't think I've used lean-find in years on mine.

@JOhnH , he does say to base your settings on the last cylinder to peak when approaching peak from the ROP side - i.e., the richest cylinder. That's the way to go.

As an aside, he may be correct that GAMIs can "usually" even out the cylinders enough to let you run LOP comfortably, but this isn't always true. I'm a GAMI customer who has never been able to get full satisfaction, and all GAMIs have done for me is to let me run a little leaner without roughness at 65% and below than I otherwise could. Typically two of my cylinders are 50-75 LOP and two are right around peak or only slightly LOP at the point where roughness starts. This isn't GAMI's fault, there is clearly something not quite right with my engine or fuel injection system (GAMI replaces only the nozzles), but it's been looked at by no fewer than 3 mechanics and no one has been able to figure out the reason.

I admit that my engine is an unusual case though, and most people with FI engines should be able to run LOP even at high power with GAMIs.
 
iamtheari said:
One thing he didn’t say is one of the reasons that one of the times when it makes sense to run ROP is during the climb: If you forget to touch the mixture knob while increasing altitude, the mixture will enrichen on its own due to the air thinning out. If you are ROP, it will stay ROP. If you are LOP, it will edge richer right into the red box, which is large because you are probably climbing at more than 65% power.
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Actually, he did mention that ROP during takeoff and climb is a good idea - basically anytime you want maximum power - unless required because of density altitude.
 
azure said:
Actually, he did mention that ROP during takeoff and climb is a good idea - basically anytime you want maximum power - unless required because of density altitude.
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Yeah, I worded my comment to point out that what he left out was this specific reason for flying ROP during the climb. You are right that he did say that the climb is a good time to fly ROP.
 
azure said:
Yep. Some models (mine, for instance, an EDM-700) can only lean-find from the ROP side so it's not as useful for LOP. I don't think I've used lean-find in years on mine.

@JOhnH , he does say to base your settings on the last cylinder to peak when approaching peak from the ROP side - i.e., the richest cylinder. That's the way to go.

As an aside, he may be correct that GAMIs can "usually" even out the cylinders enough to let you run LOP comfortably, but this isn't always true. I'm a GAMI customer who has never been able to get full satisfaction, and all GAMIs have done for me is to let me run a little leaner without roughness at 65% and below than I otherwise could. Typically two of my cylinders are 50-75 LOP and two are right around peak or only slightly LOP at the point where roughness starts. This isn't GAMI's fault, there is clearly something not quite right with my engine or fuel injection system (GAMI replaces only the nozzles), but it's been looked at by no fewer than 3 mechanics and no one has been able to figure out the reason.

I admit that my engine is an unusual case though, and most people with FI engines should be able to run LOP even at high power with GAMIs.
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What kind of engine? I was told by GAMI reps that it does not work well or makes difference if you have Lycoming engines. I actually wanted GAMI when I OHed the engine but thats what they told me.
 
blueskyMD said:
What kind of engine? I was told by GAMI reps that it does not work well or makes difference if you have Lycoming engines. I actually wanted GAMI when I OHed the engine but thats what they told me.
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I assume you tried to swap the lean injectors with the richer ones to see if it makes a difference?
 
blueskyMD said:
What kind of engine? I was told by GAMI reps that it does not work well or makes difference if you have Lycoming engines. I actually wanted GAMI when I OHed the engine but thats what they told me.
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Interesting, how long ago was that? Yes mine is a Lyc, 200hp IO-360-A1B6. But the GAMI guys told me nothing of the sort and actually their chief tech person (John Paul I think his name was) was quite baffled and recommended I have the cam looked at. This was back around 2013.
 
No What I meant was that installing GAMI in IO 540 will not make a huge difference compared to stock injectors according to them. If I remember correctly I was told that 300 HP continental benefit much more than 300 HP Lycoming. I am not sure if they even have STC for my engine. Then one guy at my airport suggested to tell engine shop to " match the injectors to fuel flow " Not sure what that means but I told them and they say they will do that. And despite of having no GAMIs I am able to fly lean of peak without running engine rough. The only problem is speed penalty is quite steep when I do it so now I adjust the power with mixture . Throttle wide open at any altitude , RPM set to 2300 and work the mixture back and forth with need for power.
 
Great video. Thanks for sharing.
I'd say no matter what the savings were exactly, a good engine monitor pays for itself pretty quickly in fuel alone...aside from helping out the engine.
 
SoCal RV Flyer said:
When you're flying a Bo, saving a little fuel should be pretty low on the list of priorities. The whole idea of having a faster plane is to use its speed to get to a destination more quickly! :D

My simplified version of leaning (this is with an injected engine and fixed-pitch prop)...maintain my takeoff EGT as I climb for safe ROP operation, typically around 1250 degrees. This, for a typical 50-mile breakfast run, say, at 5500 feet and 2350-2400 rpm. No need to press the speed on shorter flights...I actually want them to last longer just for the enjoyment of being airborne. :)

For a longer trip, I'm always above 8000' DA, where the engine is making 75 percent power or less and I can't hurt the engine no matter what I do with the mixture knob. Here, I just set speed by leaning to a particular fuel flow: 7.0 gph economy cruise (almost never) or 8.0 gph performance cruise (yeah, that's the ticket!). Don't really care where the rpm lands, as long as it's under 2750.

At performance cruise I shoot for 400 degrees CHT max on the hottest cylinder; if it inches up to 401, I lean the mixture just a tiny bit until I see the CHT drop.

I can't stand LOP operation where the engine runs rough!
Click to expand...

Personally I never let my CHT's above 380 and I run LOP. With all due respect if your engine runs rough LOP you are not doing it correctly IMO. I run LOP and she purrs like a kitten. But your engine - your rules - run her hot and rich if you prefer.
 
EminiTrader said:
Personally I never let my CHT's above 380 and I run LOP. With all due respect if your engine runs rough LOP you are not doing it correctly IMO. I run LOP and she purrs like a kitten. But your engine - your rules - run her hot and rich if you prefer.
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Well, in MY opinion, YOUR opinion is either wrong, or stated incorrectly. If my engine runs rough LOP, there is nothing I can do other than have an A&P (IA) find out what is wrong with my engine/ignition/fuel system.
 
iamtheari said:
One thing he didn’t say is one of the reasons that one of the times when it makes sense to run ROP is during the climb: If you forget to touch the mixture knob while increasing altitude, the mixture will enrichen on its own due to the air thinning out. If you are ROP, it will stay ROP. If you are LOP, it will edge richer right into the red box, which is large because you are probably climbing at more than 65% power.
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He did cover that in the video.
 
Glen R said:
He did cover that in the video.
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I didn't hear him say that the mixture richens as you climb and can richen into the red box if you started out LOP. Maybe I zoned out for a few seconds. It's been known to happen. :)
 
blueskyMD said:
No What I meant was that installing GAMI in IO 540 will not make a huge difference compared to stock injectors according to them. If I remember correctly I was told that 300 HP continental benefit much more than 300 HP Lycoming. I am not sure if they even have STC for my engine. Then one guy at my airport suggested to tell engine shop to " match the injectors to fuel flow " Not sure what that means but I told them and they say they will do that. And despite of having no GAMIs I am able to fly lean of peak without running engine rough. The only problem is speed penalty is quite steep when I do it so now I adjust the power with mixture . Throttle wide open at any altitude , RPM set to 2300 and work the mixture back and forth with need for power.
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Well I've definitely heard that many FI Lycomings are able to fly LOP with stock factory nozzles. I've never heard that it would make little difference for the others, but I can't speak to the IO-540 as I've never flown with one. How much speed penalty is steep? I lose 5-10 kts typically. It's noticeable enough that I usually avoid LOP when flying against a strong headwind, and sometimes dial in a little fuel when flying through areas with downdrafts.
 
iamtheari said:
I didn't hear him say that the mixture richens as you climb and can richen into the red box if you started out LOP. Maybe I zoned out for a few seconds. It's been known to happen. :)
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No, I didn't hear him explain that point either, and it's a good one. But he did mention the climb specifically as one of the times you probably want to be ROP.
 
EminiTrader said:
Personally I never let my CHT's above 380 and I run LOP. With all due respect if your engine runs rough LOP you are not doing it correctly IMO. I run LOP and she purrs like a kitten. But your engine - your rules - run her hot and rich if you prefer.
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RVs are more tightly cowled than most, so CHTs tend to run hotter. Ambient temps are a little warmer here in SoCal than many other parts of the country, so there's that too.

Not all engines run smoothly LOP, contrary to your belief. Yours does? Then consider yourself lucky.
 
Carbureted engine cylinders seldom peak at the same time. Some might. The effect of this is the leanest cylinder is so lean it is missing and the richest cylinder isn't lean enough to get it out of the "red zone". The pilot can try carb heat and see if it helps.

There isn't anything that can be done to fix this. There is no adjustment for the flow of fuel air to the cylinders with carb engines. That is fixed by the geometry of the intake system and there is no adjustment. There is no way to adjust the fuel/air mixture to any one cylinder. You just lean or richen the carb with the mixture knob, and take what you get.

If you are running at more than 65% power, the pilot should run rich of peak.
If the pilot runs at 65% power or less and just lean the engine until it runs rough and richen a little so it runs smooth. The richest cylinder may be in the red zone, but because you are running below 65% power it wont hurt anything. Essentially what you do is "lean to peak rpm". Dont really need an EGT gauge to do this, just look at the tachometer and listen to the engine.
 
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azure said:
Yep. Some models (mine, for instance, an EDM-700) can only lean-find from the ROP side so it's not as useful for LOP. I don't think I've used lean-find in years on mine..
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azure - You are missing out with your EDM-700! It can indeed do lean-find for LOP operation. You simply hold the STEP and LF buttons down simultaneously for a couple of seconds and the display will read "LEAN-L" instead of "LEAN-R". Now, it is in lean-find LOP mode. As you know, in LEAN-R mode (ROP mode) it finds the first cylinder to peak, and then you enrichen from there. But in LEAN-L mode, it finds the last cylinder to peak, and then you keep leaning as it shows you how many degrees lean of that cylinder you are.

By the way, my Lycoming IO-360-C1C was factory overhauled in 2007. I got the roller tappets, and the cool thing is that Lycoming now makes a serious effort to balance the injectors, so that GAMIs really aren't needed. My GAMI spread was so low that GAMIs were not necessary. I forget but I want to say the GAMI spread was .2 GPH, but it might have been .5 GPH. It was tight.
 
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