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Understanding LOP Operations - A Summary of John Deakin's Knowledge

I'm still learning about leaning. So one of my questions were what happens if all the clyinders are not at the same tempature. Do you lean on ROP to the hotest cylinder and use it's EGT to set the whole engine. And then what do you use on the LOP side do you still use the hotest cylinder? So if your engine has a spead of CHT's what do you use because if you use the wrong CHT then you could have the other cylinder running in the red zone I think.

Reading your EGTs, on the rich side you lean based on the cylinder that peaks first whereas on the lean side, you use as reference the cylinder that peaks last.

Moura
 
WWII ERA FUEL/AIR RATIO INSTRUMENT

An aviation WWII era fuel/air ratio instrument? I haven't seen anything like this in an airplane but if you had that number, you'd have a tool to do LOP.

A key source for modern LOP operations and the Advanced Pilot Seminars is Rice's 1957 "Basic theory of operation of the turbo compound engine". Rice reports on how they used the torque meter indicating torque drop to get the engines into the target zone (as mixture was leaned, torque dropped). These days we use well balanced cylinders and EGT drop as a measure of LOP operations.

This looks like something else entirely. Doesn't look like a torque meter or anything to do with EGT. I'd think we are looking at the display and signal processing unit. Was this system looking at mass flow for each or was it only estimating fuel air ratio by some indirect method?

http://www.ebay.com/itm/37045538029...AX:IT&_trksid=p3984.m1423.l2649#ht_5121wt_935

I'm aware of the ebay ban in the classifieds. I trust moderators can see this is LOP related. I don't know the seller, just ran across it looking for something else. I've asked them the same question.
 
At less than 75% power, the engine can not be harmed by leaning, it might quit if you're too aggressive but you can not harm it. :)

This is what I have always been told/used. I've been flying small Lycomings since 1986 using that. This is why many rental places and flight schools ask people NOT to lean below 5000 MSL. Above 5000 MSL, MP will be < 25" (almost always) and therefore the engine is <75% power and cannot be damaged by bad leaning.

Mike Busch on EAA videos and webinars has great info that goes far beyond "don't lean below 5000, do whatever you want above it". I will try flying around LOP for awhile.

However, on "dumb" planes like mine that are carbureted and have only 1 EGT probe I don't how Mike Busch and Deakins' advice can really be followed, not enough info to the pilot. For me, leaning to rough and then a bit richer works.

That said, I am all for advancing knowledge, technique and skill. If you can run LOP try it, I will. I am confident that at <75% it is very hard to damage an O-360.

One other thing: The most important thing to do while flying VFR is look outside for terrain and traffic. What we need is something fast/simple to do with the engine. I really like the idea of "parking" the engine. I have not heard this phrase before but it is correct, b/c you really don't want to be heads down in the air.
 
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LOP

I have an ECI IO360 with 9 to 1 compression ratios. In the summer, I have a problem with the CHT's going up to 425* or so. (And the oil gets too hot also) So I became an advocate of Mike Busch's LOP operations. I don't have a heck of a lot of piston time, so here's my question. If you're going to operate at umpty ump degrees above peak, say 125 ROP, or umpty ump degrees LOP, how do you do this without first putting your engine right at peak, ie right in the worst position inside the red box? I've just been doing Busch's "big mixture pull", and then pulling til slight engine roughness, then enriching til smooth operation. This takes care of my CHT's. They then run below 380*. My Dynon D180 always shows 63% LOP after I do this, but I have no idea how accurate that is or isn't.

Sure appreciate any help from you guys who know this stuff.
 
Sounds about right to me!

I have an ECI IO360 with 9 to 1 compression ratios. In the summer, I have a problem with the CHT's going up to 425* or so. (And the oil gets too hot also) So I became an advocate of Mike Busch's LOP operations. I don't have a heck of a lot of piston time, so here's my question. If you're going to operate at umpty ump degrees above peak, say 125 ROP, or umpty ump degrees LOP, how do you do this without first putting your engine right at peak, ie right in the worst position inside the red box? I've just been doing Busch's "big mixture pull", and then pulling til slight engine roughness, then enriching til smooth operation. This takes care of my CHT's. They then run below 380*. My Dynon D180 always shows 63% LOP after I do this, but I have no idea how accurate that is or isn't.

Sure appreciate any help from you guys who know this stuff.

Sounds like you are doing it right. But -- you might have a look at your cooling system - the 425F CHTs you mention are a bit high. DanH has a great thread on the -8 cooling system.

Dynon: I think it uses a formula to 'estimate' you power percentage. When I get my engine just so, the Dynon also says ~63% and LOP. For my purposes, that is about 22"/2200 and 11GPH.

Carry on!
Mark
 
If you're going to operate at umpty ump degrees above peak, say 125 ROP, or umpty ump degrees LOP, how do you do this without first putting your engine right at peak, ie right in the worst position inside the red box? I've just been doing Busch's "big mixture pull", and then pulling til slight engine roughness, then enriching til smooth operation. This takes care of my CHT's. They then run below 380*.

Peak is not the worst position. Roughly 50 ROP is worst, and it's not a horror story at lower power settings. So, don't linger at high power settings in the area around 50 ROP. Put another way, don't lean slowly through that range at high power settings, in particular when running oversquare.

How to avoid it? Just do what you're already doing. The Big Pull is taking you directly to somewhere LOP. If you wish to determine exactly how far LOP you are, find peak by creeping up on it from the backside, i.e. from the LOP side.
 
More LOP---ROP

Thanks F1Boss and Dan H. That's exactly the help I was looking for. One more thing if I may. Today I'm going out formation flying for the first time with an RV 4. When your flying wing, one is jocking the throttle all over the place to hold position. LOP goes out the window. I'm planning to run 2500 RPM and either full rich or or leaned just enough to give 1350 EGT (which is the EGT I get on takeoff-full power. )

Does this sound good to you guys??:confused:
 
Thanks F1Boss and Dan H. That's exactly the help I was looking for. One more thing if I may. Today I'm going out formation flying for the first time with an RV 4. When your flying wing, one is jocking the throttle all over the place to hold position. LOP goes out the window. I'm planning to run 2500 RPM and either full rich or or leaned just enough to give 1350 EGT (which is the EGT I get on takeoff-full power. )

Does this sound good to you guys??:confused:

It depends on what you are doing. Mixture is typically set when you get kicked out enroute for your first ops check.

I would hope you have had your ride along and have been cleared by an experienced safety pilot for two ship solo operations. This is where you learn these types of things.
 
It depends on what you are doing. Mixture is typically set when you get kicked out enroute for your first ops check.

I would hope you have had your ride along and have been cleared by an experienced safety pilot for two ship solo operations. This is where you learn these types of things.

John Jay,-----flew formation in the military, but thanks for your input
 
John Jay,-----flew formation in the military, but thanks for your input

Thank you for your service.
There are some great resources from Formation Flying Inc. who runs the program specific to formation flying with RV's. Even our most experienced military formation pilots are required to start at ground zero in the program to insure consistency in training and operations. It is a stepped program that benefits all who are interested in flying RV's in formation.

In most formation flying configurations, I like to be significantly rich, especially when you first start out. As you know, your eyes can not leave lead to look into the cockpit. After time, you can fine tune your mixture settings to be a bit less conservative.

Hope that helps.
 
25" MP

I'm flying with a fixed pitch prop (Catto) and a Dynon EMS 120. Is it an "absolute" that anytime you are below 25" MP you are below 75% power?

I think the Dynon uses some calculation using MP and RPM, and I assume fuel flow to give a % power reading. My Catto will turn more than 2600 at 5000 DA and I think that messes up my power readings. Therefore I've used the rule of 48's I think it is.

It would be simpler to know that if I'm below 25" of MP then I can lean as I wish.
 
I'm flying with a fixed pitch prop (Catto) and a Dynon EMS 120. Is it an "absolute" that anytime you are below 25" MP you are below 75% power?

I think the Dynon uses some calculation using MP and RPM, and I assume fuel flow to give a % power reading. My Catto will turn more than 2600 at 5000 DA and I think that messes up my power readings. Therefore I've used the rule of 48's I think it is.

It would be simpler to know that if I'm below 25" of MP then I can lean as I wish.
Not quite sure what you are referring to concerning "rule of 48's". Whatever that is about, I think using % HP is a WAG regardless of which EFIS manufacturer being used in reference to how the % HP read out is calculated. If you are adamant about using a 75% number then be aware that even the best of calculations are an estimate. Which is still OK. Your engine will not instantly blow up if it actually is 76% or something. However, I think it perhaps may be wiser to take what Mike Busch discusses and think more in terms of CHT rather than % HP to determine when or if one runs LOP. We are concerned with detonation and pre-ignition and all that stuff anyway, are we not? Those are functions of heat after all, so, why not utilize information that deals with heat? Keeping the CHT for each cylinder south of 400 deg F will do better than trying to rely on some theoretical calculation of % HP that may or may not be correct. As long as the CHT is not above 400 deg F there is little chance of "blowing up" something regardless of what engine setting you are running, what altitude you are flying, the temp outside, the phase of the moon, or whether your engine slept in a Holiday Inn last night. :)
 
I'm flying with a fixed pitch prop (Catto) and a Dynon EMS 120. Is it an "absolute" that anytime you are below 25" MP you are below 75% power?

I think the answer is NO. I looked at the Lycoming I/O 360 Operator's Manual and I believe 75% is ~ 24" 2400 RPM. That gives 150 HP for IO-360 and something comparable for O-360 (something like 135 or 140 HP). Many climb at 25/25, and it is definitely >75%. Interestingly, the Extra 200 POH says to TO WOT (of course) and then pull RPM to 2500 as soon as practicable, which is very subjective (800 AGL?). They recommend WOT in the climb. I believe Mike Busch does this too, and recommends it in his EAA video on leaning.

http://bcove.me/xcda4t0b

Watched it, again, last night. Very informative. Most info is for Turbocharged airplanes. Leaning for I/O-360s is very simple. First 10 minutes of the video covers normally aspirated.
 
John Deakin - Gone West at 81

It is with enormous sadness I bring the news of one of natures greatest gentlemen has departed the living, and may he rest in peace.

Just over a year ago I lost a great mate, Walter. This year, another year of all this Covid madness, means once more I have not been able to be with and visit some of the most important people in my life.

Leisa and I were blessed to Face Time with JD a few days ago. He struggled through a few minutes, came out of the blocks hard and smiled like never before when I suggested his local Waypoint Cafe malted chocolate milkshake would fix him up.

I am so blessed to have had John Deakin in my life. I will be bold enough to say everyone on BT will no doubt share the same feelings.

To Tamiko and the boys, our condolences. JD, we love you to bits mate.

You were and forever will be ..... a legend.
 
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