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Lean find mode
- Thread starter JUSTNUZZA
- Start date
jnmeade
Active Member
I'm going to follow this thread because after reading pages 5-4 and 5-5 of the user's manual, I don't understand what the OP is asking and I'm not sure I understand or agree with the response. Does it matter what engine is under discussion?
"To exit the Lean mode, press LEAN again; the EGT/CHT display then returns to its normal state." It seems to me that if in Lean mode, pressing Lean turns the mode off. Or is the answer that one uses EGT, fuel flow or some other indicator to get lean of peak and THEN presses LEAN? Sorry to be so dense. When I ran LOP it was with different instruments so I'm trying to adjust my sight picture here.
"To exit the Lean mode, press LEAN again; the EGT/CHT display then returns to its normal state." It seems to me that if in Lean mode, pressing Lean turns the mode off. Or is the answer that one uses EGT, fuel flow or some other indicator to get lean of peak and THEN presses LEAN? Sorry to be so dense. When I ran LOP it was with different instruments so I'm trying to adjust my sight picture here.
The idea I am trying is to aggressively lean the engine to L.O.P to get through the worst engine operating area around 50 R.O.P. Then you can richen back to peak egt then lean again to avoid that area for L.O.P or decide to operate R.O.P by richening quickly avoiding that area again.I'm going to follow this thread because after reading pages 5-4 and 5-5 of the user's manual, I don't understand what the OP is asking and I'm not sure I understand or agree with the response. Does it matter what engine is under discussion?
"To exit the Lean mode, press LEAN again; the EGT/CHT display then returns to its normal state." It seems to me that if in Lean mode, pressing Lean turns the mode off. Or is the answer that one uses EGT, fuel flow or some other indicator to get lean of peak and THEN presses LEAN? Sorry to be so dense. When I ran LOP it was with different instruments so I'm trying to adjust my sight picture here.
jnmeade
Active Member
Since peak is an undesirable state and one doesn't want to go through it slowly, why go through it quickly and then go back to it as a reference point before going LOP again?
It's been 10 years since I ran LOP in a Continental IO540, so my experience may be dated and i am not trying to advise, I'm only chatting/learning. When I did it, I had developed some experience of the EGTs I wanted to see by cylinder. I equated them with fuel flow. When I did the big pull, I went right to fuel flow and then checked that the EGT was where I expected/wanted it by cylinder. I never had to go to peak except on the pretty rapid "big pull".
Is this method no longer so good with the new avionics?
(Yes, I'd love to have an injected engine again so I could fly LOP.)
It's been 10 years since I ran LOP in a Continental IO540, so my experience may be dated and i am not trying to advise, I'm only chatting/learning. When I did it, I had developed some experience of the EGTs I wanted to see by cylinder. I equated them with fuel flow. When I did the big pull, I went right to fuel flow and then checked that the EGT was where I expected/wanted it by cylinder. I never had to go to peak except on the pretty rapid "big pull".
Is this method no longer so good with the new avionics?
(Yes, I'd love to have an injected engine again so I could fly LOP.)
DBRV10
Active Member
Peak is not that even, and even going slowly though the peak to 100 ROP is not that dangerous either. People get too scared over more OWT's.
The reason you should pull through quickly is the cylinders do not get a chance to heat up. You get a better result finding true peak EGT this way. It is also fast and efficient. Less time head down stuffing about. Big Mixture Pull once refined gets you where you want to be no matter what % power you are at.
And you can fly LOP in a carby engine. Who said you can't? They are wrong. Just get your carby engine set up right and it will.
The reason you should pull through quickly is the cylinders do not get a chance to heat up. You get a better result finding true peak EGT this way. It is also fast and efficient. Less time head down stuffing about. Big Mixture Pull once refined gets you where you want to be no matter what % power you are at.
And you can fly LOP in a carby engine. Who said you can't? They are wrong. Just get your carby engine set up right and it will.
jnmeade
Active Member
David, your comments lead me to do some more research and I ended up back at references and research at GAMI and with Mike Busch. Thanks for prodding me to refresh my memory. I'm satisfied that I know how and why I am going smoothly and quickly through peak EGT and I will no longer discuss it here.
" And you can fly LOP in a carby engine. Who said you can't? They are wrong. Just get your carby engine set up right and it will. " Of course this is true. It begs us to explore what it takes to get the engine set up right and that's a good challenge you've posted. In the case of my Rotax 912ULS that may be quite an adventure.
" And you can fly LOP in a carby engine. Who said you can't? They are wrong. Just get your carby engine set up right and it will. " Of course this is true. It begs us to explore what it takes to get the engine set up right and that's a good challenge you've posted. In the case of my Rotax 912ULS that may be quite an adventure.
DBRV10
Active Member
Ahhh a Rotax 912 is a ROP machine.....You cant change that.
As for research.....GAMI is a good reference. I am one of 5 APS teachers, GAMI's George Bayly being one of us. Mike Busch is a student of APS, he did the class 3 times. Not because he is dumb, just he wanted to be a student of the science. One of our partners John Deakin and George Bayly started conversing back 25 or so years ago.......that is where we got the modern LOP era from.
I am happy to answer your questions. The challenge you accepted however really requires a manual mixture control. Rotax do not give you that. The 912iS however does run LOP.....you have no control though.
If you ant good research go here..... https://www.avweb.com/features/avweb-classics/pelicans-perch/pelicans-perch-index/
Scroll through to the bottom (article one) and read all of them. Deakin is a legend of aviation and writing. By the way Avweb was started by Mike Busch and John Deakin was one of his "Rockstar" writers back 20 years ago. I am privileged to call him a friend and partner.
As for research.....GAMI is a good reference. I am one of 5 APS teachers, GAMI's George Bayly being one of us. Mike Busch is a student of APS, he did the class 3 times. Not because he is dumb, just he wanted to be a student of the science. One of our partners John Deakin and George Bayly started conversing back 25 or so years ago.......that is where we got the modern LOP era from.
I am happy to answer your questions. The challenge you accepted however really requires a manual mixture control. Rotax do not give you that. The 912iS however does run LOP.....you have no control though.
If you ant good research go here..... https://www.avweb.com/features/avweb-classics/pelicans-perch/pelicans-perch-index/
Scroll through to the bottom (article one) and read all of them. Deakin is a legend of aviation and writing. By the way Avweb was started by Mike Busch and John Deakin was one of his "Rockstar" writers back 20 years ago. I am privileged to call him a friend and partner.
jnmeade
Active Member
I'm sure you detected that I spoke of setting the Rotax 912ULS up to run LOP with tongue in cheek. I guess you can call the Rotax 912ULS an ROP engine. It uses Bing 64 carbs which are constant velocity carburetors and thus it internally adjusts fuel flow to match air velocity up until it runs out of adjustment. Brian Carpenter of Rainbow Aviation has some excellent articles and YouTube videos on the operation and design of the Bing 64. Old motorcycle mechanics know all about them.
I've long ago read Deakin's stuff and am a long time AvWeb subscriber from back when Busch was still active daily in it. I don't know Deakin but I know Busch to talk to. It's not a bad idea to refer to the articles from time to time.
As the FAA now calls us, we're all "learners" but this isn't my first rodeo.
I've long ago read Deakin's stuff and am a long time AvWeb subscriber from back when Busch was still active daily in it. I don't know Deakin but I know Busch to talk to. It's not a bad idea to refer to the articles from time to time.
As the FAA now calls us, we're all "learners" but this isn't my first rodeo.