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  #101  
Old 08-16-2011, 02:27 PM
Moura Moura is offline
 
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Originally Posted by grewerts View Post
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
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  #102  
Old 03-24-2012, 08:48 AM
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nomocom nomocom is offline
 
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Default 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/370455380294...#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.
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  #103  
Old 03-17-2015, 07:33 AM
Daveontheroad11 Daveontheroad11 is offline
 
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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.

Last edited by Daveontheroad11 : 03-17-2015 at 07:35 AM.
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  #104  
Old 03-17-2015, 10:40 PM
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donaziza donaziza is offline
 
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Question 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.
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  #105  
Old 03-18-2015, 01:42 AM
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F1Boss F1Boss is offline
 
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Default Sounds about right to me!

Quote:
Originally Posted by donaziza View Post
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
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  #106  
Old 03-18-2015, 04:38 AM
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DanH DanH is online now
 
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Quote:
Originally Posted by donaziza View Post
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.
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  #107  
Old 03-18-2015, 08:14 AM
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donaziza donaziza is offline
 
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Question 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??
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  #108  
Old 03-18-2015, 08:32 AM
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JonJay JonJay is offline
 
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Originally Posted by donaziza View Post
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??
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.
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  #109  
Old 03-18-2015, 08:50 AM
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donaziza donaziza is offline
 
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Originally Posted by JonJay View Post
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
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  #110  
Old 03-18-2015, 09:08 AM
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JonJay JonJay is offline
 
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Originally Posted by donaziza View Post
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.
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