1. When I lean the A36 I have to bring the mixture control back to about 40% to get to peak EGT. Isn't that a lot...? 2. Do you have to lean every now and then? If so, how often? I found out that a short while after leaning the mixture things had changed, because when I did it again, I got completely different results. Or didn't I do it well the first time...?Here's how I do it (with the EDM 700). When in cruise (throttle and prop in good settings) I press the LeanFind button and start leaning the mixture. As soon as the bars reach the top and the numbers don't go up anymore, I take a note of the number, press the LeanFind again (turning the LeanFind off), and bring the mixture lever back up until the number is 20 lower. So if the highest number is 1580 I put it on 1560. That's it. Right...?Another question... Lowering this number is called RICH of peak EGT (you move the mixture control up so you add to the mixture, making it richer). But... how do you set it LEAN of peak EGT...? Most charts included with the A36 say you have to LEAN the mixture... But when I reach the highest number I cannot go higher anymore... So I cannot make it LEAN... Or am I mistaken about something here...? I must be... ;)

Mixture varies for density altitude (air density as determined by altitude and temperature) because the oxygen content varies according to it. Mixture must be varied as you change altitude and if the OAT changes significantly such as flying through a front.Peak EGT means the engine is running at the highest combustion efficiency, but generally you stay slightly on the rich side side to avoid "hot spots" in the engine.If you are taking off on a hot day especially at a high altitude airport, when you run up the engine for the take-off roll, you lean for maximum power or you may not have enough to lift off properly for runway length and obstacle clearance. As you climb you adjust the mixture about every thousand feet or so keeping an eye on throttle adjustment to control the manifold pressure (power adjustment) according to your performance charts as it will also be affected by altitude.If you have a turbo-charged (not turbo-prop) aircraft, there is less of a requirement to adjust mixture since air is compressed and regulated to make up for the loss of oxygen as density altitude increases.In the reverse operation of descending, you richen the mixture accordingly.If your are past the peak of the power curve and leaning too much, the engine will starve for fuel, EGT and power will drop, and since there is no "window" for such power loss it is not a good place to be.I many years ago flew a real A36 and was encouraged to adjust just on the rich side of peal EGT. Performance parameters may have changed since then.

Hello:You can take a look at this tutorial if you would like.hope it helps:)http://stoenworks.com/Tutorials/Throttles,...ures%20and.htmlcheersTrapper

The leaning portion of the program in FS is certainly flawed. There's not a lot of similarity between FS and the RW in leaning. So, it could be possible that you pull the mixture out 40% in FS. I've seen this topic over in the Dreamfleet forum. I believe they also said this was a problem with the simulator and not the a/c. I tend to believe them as I haven't found the fs modeling of leaning to be worth messing with. But, to each his own.IRL I lean quite a bit during climb and descent (above 3000). With gas prices and the cost of overhaul, I like to make sure that I'm maximizing value. IRL, as you demonstrated, you would use whichever technique you preferred. I usually run rich of peak because I prefer to have a little longer time with my engines before they have to be overhauled in exchange for greater fuel consumption. But a lot of my friends run lean of peak and they have good arguments as well. Well, that may not have been any help at all, but thanks for reading anyway.best

>Here's how I do it (with the EDM 700). When in cruise>(throttle and prop in good settings) I press the LeanFind>button and start leaning the mixture. As soon as the bars>reach the top and the numbers don't go up anymore, I take a>note of the number, press the LeanFind again (turning the>LeanFind off), and bring the mixture lever back up until the>number is 20 lower. So if the highest number is 1580 I put it>on 1560. That's it. Right...?As the programmer for the EDM700 in question, I might just have some insight into this question... ;)You are missing something in your procedure:The entire purpose of the LeanFind is to - well - find the highest EGT on a specific cylinder. After engaging LeanFind, you will lean the mixture until, as you've noted above, the digital display "locks" at the peak EGT for the "hottest cylinder" (which, because of FS limitations, will always be #5). This "limitation" isn't all that unrealistic though, since #5 will nearly always be the hottest cylinder because of its location within the normal airflow around the engine cowling.After finding the "Peak EGT," disengage the LeanFind, then either push the mixture knob back in - richer - or continue pulling it out further - leaner.The digital display will allow you to either enrichen or lean the engine, and provide the exact temperature for you.As an example, suppose LeanFind tells you that the Peak EGT is 1580

Thanks for the great link! forgive my ignorance about mixture... but this only applies to a prop aircraft? What about a jet such as the PMDG 737? Does that do everything by itself?

It only applies to normally carburated, reciprocating engines.Fuel-injected and turbine engines don't have a 'mixture control,' at least not in the same way as used on the above mentioned engines.Computers meter the fuel/air mix automatically for fuel-injected and turbine engines.

Hi Bill;"(Note that different engines require a different delta value for ROP or LOP mixture.thats why consulting the POH is critical.)"Well said.!"Know the Aircraft"cheers Trapper

>It only applies to normally carburated, reciprocating>engines.>>Fuel-injected and turbine engines don't have a 'mixture>control,' at least not in the same way as used on the above>mentioned engines.>>Computers meter the fuel/air mix automatically for>fuel-injected and turbine engines.The majority of fuel injected airplane engines such as Lycomings and Continental's still have that "red" mixture lever, even though some are going with computer controls now. Examples are the newer Cessna 172's (R & SP) & Piper Arrow. Fuel injected but with mixture knobs. I have a carbed Lycoming, but will have to see how the mixture actually works with a fuel injected throttle body, etc...................as now I'm wondering.L.Adamson

>The leaning portion of the program in FS is certainly flawed.> There's not a lot of similarity between FS and the RW in>leaning. So, it could be possible that you pull the mixture>out 40% in FS. I've seen this topic over in the Dreamfleet>forum. I believe they also said this was a problem with the>simulator and not the a/c. I tend to believe them as I>haven't found the fs modeling of leaning to be worth messing>with. But, to each his own.>Leaning in FS usually matters with altitude steps such as 6000, 8000, and up. Not exactly real, but it's a decent representation of loss of engine power if you don't lean. Since I fly at a 4600'msl airport to start with, I always lean the FS airplane right after startup. Actually , the sim plane is already leaned, as it's already started with a saved flight. 6000' is the first real critical altitude modeled in FS. The engine starts on it's downward power drain at that point, if you don't simulate leaning.FWIW--- With the Piper Archer I used to fly. The mixture knob could easily be pulled halfway back on the throttle quadrant for takeoff. Was probably a 6000+ density altitude day, for a 4600' airport. My simulated airplanes are usually at around 70% for duplicating these airports.L.AdamsonL.Adamson

>As the programmer for the EDM700 in question, I might just>have some insight into this question... ;) Wow! Well, I couldn't wish for a better man to answer my post! :) Thanks for the excellent and extensive explanation! It's all clear now! But er... you said I was missing something in my procedure, but as I see it, I did exactly what I was supposed to do (to lean rich). Right...? Maybe I didn't understand what I was doing yet, but I did the right things... if I'm not mistaken...

>But er... you said I was missing something in my procedure,>but as I see it, I did exactly what I was supposed to do (to>lean rich). Right...? Maybe I didn't understand what I was>doing yet, but I did the right things... if I'm not>mistaken...You are most welcome!Specifically, you had written:"Another question... Lowering this number is called RICH of peak EGT (you move the mixture control up so you add to the mixture, making it richer).""Lowering this number" can be, as I explained in my reply, either ROP or LOP.The reasons for the temperature drop are different, but how could you not have a temperature drop on either side of the "peak?" :( Isn't that the precise reason it's called a "peak?" *:-* However, you have been "doing it right" whether you understood what was happening or not, as you said! ;) Hopefully, this thread will help someone else who may have been confused or uncertain, and too shy to ask.Thanks for the question!

Ah, yes, okay, indeed, at first I thought that ROP would lower the temp and LOP would raise it even further, which of course didn't happen, hence one of my questions. Luckily I'm never shy enough to ask 'stupid' questions, although of course usually stupid questions only become stupid after you've read the answer: I'd never ask a stupid question if I KNEW it was a stupid question! :)It was indeed a ridicilous thought because, as you said, you cannot get higher than a peak! I don't know how I got that idea but somehow it seemed logic: I just didn't now know the temp would drop at both sides of the peak for different reasons. I did see that happen of course, when I lowered the mixture control more and more, but somehow I though that was wrong... Well, how wrong was I... ;)Well, it's certainly all clear to me now! Thanks again!