Martin, as a retired NASA astronaut, space shuttle captain, and SR-71 owner for 20 years, I have to say I'm impressed with your ability to explain how to lean a piston engine in only half an hour. Good job and THANK YOU for making such quality content!
@martinpauly I think this was said in humour....because of all the other people replying and quoting their resumes. Like any of that has anything to do your video....
Martin, as a military and professional airline pilot with over 27,000 hours, as well as Bonanza owner of fifteen years, I have to say I am impressed again with your ability to explain often confusing topics in simple terms. Nicely done and keep up the fine work!
Thanks, Bruce - I appreciate the kind feedback. There are a lot of misunderstandings and myths about mixture management when in reality it is not such a difficult topic. - Martin
Martin, as both an aerospace engineer and a retired USAF Navigator (responsible for both preflight fuel calculations as well as enroute fuel management), I wholeheartedly endorse your video! You not only nailed the issues solid, but you covered the exceptions in a clear and notable manner. EXCEPTIONALLY well-done!
Had Martin been my professor for thermodynamics I probably would have stayed in engineering 20 years ago. Thermodynamics is hard enough without it being explained in a broken chinese accent!
Martin, as a retired captain of starship enterprise ,a NASA astronaut, space shuttle captain, and SR-71 owner for 20 years, I have to say I'm impressed with your ability to explain how to lean a piston engine in only half an hour. Good job and THANK YOU for making such quality content!
Last time you posted almost this exact comment you were "Virtualmix". I am still curious how one becomes an SR-71 owner (other than being a taxpayer). But I appreciate the kind words on this video! - Martin
Here are some words from an old CFI who soloed in 1965: "Your video is stunningly brilliant!!" I wil make this mandatory for any future student and recommend others do the same. Thank you very much!!
I fly for 30 years and never understood this topic completely, it is often explained by experts with no didactic skills. I completely understand now. Thank you so much for your talent and skills to teach!
Wow! Despite having many people, including my mechanic trying to explain me Lean of peak, I never got to fully understand. But thanks to your video, now I can feel safe using lean of peak
Martin, hopefully, you don't get tired of praise. With 10 years flying fighters in the Marines, and 25 years as an airline pilot, I've had my share of flying "lessons"! This was the best, most concise, most helpful video ever. You have a gift, Sir! Thank you for taking the time to produce this! It should be part of every GA pilot's education!
Hey Martin, GREAT video. Probably the best video I have ever seen on the topic. I am going to bring up the topic in a video and refer my viewers to this video for a better explanation.
And Martin, I just watched the video since Baron Pilot suggested it, and it reinforces all I thought I knew about LOP operations, and added additional information. Very well done, very easy to understand, and very informative.
What a great lesson. Most folks can’t describe much less define how to lean an engine and why it matters. Your video makes it very clear why it matters.
Martin, as the undercover persona of BuzzLightyear, with over 257,000hrs of intergalactic missions, I am impressed by your explanations. Keep up the good work. To infinity and beyond!
Hi Martin, I was at an aviation maintenance conference today. My vendor booth was next to the Lycoming booth. A mechanic visiting the Lyc booth and asked the representative what he thought about lean of peak vs rich of peak. The rep was struggling for an answer. I had just watched this video earlier in the week so I interrupted them both and urged them to watch your video which I still had queued up on my iPhone. The mechanic was looking for the "one size fits all" answer and I explained to him that after watching your presentation he would understand there isn't one due to many inter-relating factors. Both were very impressed with your explanation and learned a lot. Especially the Lycoming rep. He later told me he had never seen it so clearly explained. Great job! I worked for an engine accessories manufacturer; fuel systems, turbochargers, wastegates, starters, etc. for years and it was the best I've seen too. Thank you!
Thank you for spreading the word on LOP, and on this video. It sounds like this topic is still a mystery to many. I'll be at Sun 'n Fun this year, and will give a couple of presentations on this topic. Best regards, Martin
@@martinpauly My company exhibits at Sun n Fun each year. Perhaps I'll be able to sit in on one of your presentations. Good luck with it. I'm sure it will be well received. Best--
Despite reading several articles on the subject, I never really understood the mechanics behind the decision process. Very good explanation that shows a superior depth of understanding - BRAVO!
Mr. Pauly knows how to breakdown complicated jargon into simple terms so most everyone can understand what is going on. That is a valuable skill set in any vocation. Impressed.
Excellent discussion and teacher. I am reminded of my automotive racing days with normally aspirated carbureted engines. I loved the challenge of setting up an engine with various fuel flows, jets, and cam angles for the best performance of the day. This was all before fuel injection. It was fun and I learned a lot. I had to set up my own gauges inside the car for manifold pressures, EGT, and CHT. The science was fascinating! Thanks, Martin!
I've been flying my Bonanza for a year, and this was the most informative and clear explanation I've seen regarding the financial and performance impacts of LOP vs. ROP. Highly recommended for any pilot, especially if you own the plane. I will now spend most of my life at LOP, with confidence.
Martin, thank you so much for this video. I have tried to understand LOP from several sources, leaving a lot of questions behind. You explained it so simple and now I finally know what´s going on and how to deal with the airplanes I am flying. Also I love the way you explain and show examples on the instruments and charts. Thank you !!
This is a terrific video Martin. I wish more people would make videos as comprehensive as you have. This is a true reference resource. I know how much work it is to make this happen, so many thanks to you! And, by the way, thanks for recently accepting my invitation on LinkedIn. All the best, Josh
Martin, As a space shuttle owner and developer of the first, abnormally aspirated piston aircopterjet, I too am impressed with the clean and clear instruction and demonstrations. I can’t learn anything until I understand the how and why. Thank you for making it more clear. New subscriber!
Thanks for sharing...... Im a pilot that flew a lot of turboprop and turbines ,and now I will start piston engines....... It is new for me and Im learning a lot from you.Congrats! 👍👍
Just Plane Silly Hey Bryan, I’m glad you were able to make it past the word “Bonanza” - I know, it’s hard to be a fan of an airplane in which pilots practice slow flight at the taxi speed of a Cirrus. :-) Thanks for chiming in; I love your videos!
HAHAHAHAHA!!!!!!! Thank you! I have already shared this video with a handful of people. Very well done and very well simplified. If you go to Osh this year, let me know. I will buy you a beer!
How could I turn down a beer - thank you! I don't know yet if I'll be in Oshkosh this year. If I go, it'll be at the end of the event, because it is the same week as RAGBRAI, a cycling event (which is really just an athletic euphemism for "weeklong party on bikes") here in Iowa - so I am torn, and RAGBRAI usually wins. At any rate, I do hope to run into you one of these days somewhere.
@@martinpauly I just hit the like button. Actually Bryan is a changed man 😂 He seems to be creating some sort of a promotional video for the Bonanza one of these days.
In all my years on UA-cam, this is the first time i've commented on a Video. Thankyou so very much for your clear, informative and demonstrated video. You cured my headache on LOP in the first 10 mins.
Well done, Martin. I've been an advocate of LOP for many years, and your explanation is better than I could have done. My Cessna 421B has used LOP for the 40 years I've owned her, and the big GITSO 520s always make it well beyond TBO. PS: Loved the outtakes.
This is by far the best tutorial on engine leaning i have come across. I've talked to several CFIs and flying friends, and watched several UA-cam videos. But this one video breaks everything down into small bites of common language explanations that is so easy to follow. Thank you!
Thanks for the kind feedback, Tuan. Mixture management is not really all that complicated, but collectively in the aviation world we don't seem to do a good job teaching it - so a lot of misunderstanding and myths exist. That's what I was hoping to help with through this video. Best regards, Martin
Thank you, David. Making videos is just a hobby, and very different from my day job. Maybe that's one reason I like it so much - a welcome change from the office chores.
I've been looking at this subject for several weeks now and have read most of John Deakins' articles on Pelican's Perch, but I have to say that his video was the most lucid and well laid-out distillation of this complicated subject that I've seen anywhere. Really excellent. Thank you very much.
Martin, this is a fantastic video. When I first got my Mooney Acclaim I took it to a renowned Mooney expert up in Minnesota to learn how to operate LOP, which I had never done before. He gave me pretty much this exact same presentation and I know it has saved me lots of $$$ and engine wear over the past 6 years. Bravo, and thank you!
With electronic ignition you can take even more advantage of LOP. The LOP robs the engine of power since the combustion charge burns more slowly and the piston has already started "down" from top dead center by the time you have full burn of the combustion charge. With electronic ignition you can change the ignition timing, advance the spark, and return to full combustion closer to top dead center on the piston. This gives you more power out of the fuel you are burning and even more economy.
@@martinpauly As electronics engineer I full agitate against unnecessary complication when goal may be achieved witch simpler solutions. Magnetos are highly reliable, cheap and easy to maintenance. Electronics improve efficiency but is more prone to malfunction. OK, as most of systems in aviation should be redundant as magneto is (two independent systems on cylinder). Next problem to solve is powering, magnetos works autonomously but electronic ignition depends on external electricity. More points to probable failure for electronic - from engine shaft sensor/actuator, by wiring, connections to spark module at end - less trustworthy system for pilot than simple magnetos, even with more fuel cost. Life is priceless.
Best on this topic I've seen so far. I'll just add that I have a set-up that operates on aircraft without electrical systems that does the same thing; I use dual EGT and CHT gauges stacked so that the needles are laid out like the engine- two dual EGT needles with the top set for the forward cylinders and the bottom set for the rear cylinders; same with the two dual CHT gauges. These are inexpensive Westachs. In cruise, Wide Open Throttle (at altitude), a glance tells you things are good when all the opposing needles point at each other. And initially the front right CHT was low; an additional baffle brought it up so now all the CHTs are matched. I can now lean confidently in an airplane with no electrical system, which is very satisfying.
@@martinpauly It's a real comfort in flight to see those needles behaving. You can also see those CHTs come down across the board as you continue to lean past peak EGT- I never trusted rotary switches to select probes (it doesn't take much noise in switching to throw those faint currents off), so having the baffling right and seeing even temps all through the leaning procedure is a real confidence builder. You don't have to do anything but manage mixture and power and just glance over to see what is going on. I typically take off full rich/full power and then when I turn crosswind I make a power reduction to the bottom of the green arc on the tach, then lean back up to the middle of the green. Then as I cruise climb I repeat that after a minute or two by leaning slightly out the bottom of the green and bringing it back by advancing the throttle. After 4 or 5 gentle iterations, I'm at Wide Open Throttle, at about 7000' of DENSITY altitude, and nicely stabilized at the Norris Point, or 1.316 times max ROC IAS. With a C-85 I'm burning less than 4 GPH. I do have a forbidden RPM band with a McCauley Klip-Tip prop, so dancing around that green arc on the tach is a low stress procedure (well away from the forbidden band) and especially because the temps are in friendly territory. These are 2" instruments clustered in not much more space than a single 3" instrument. I'm converting every airplane I own to this setup. And again- no electrical system required.
Clear and concisely explained. Thank you. I used to tune carbureted two stroke racing motors. Lean was bad due to the cooling factor of the fuel. Your 4 cycle tuning chart, backed up by actual demonstration makes all the sense in the world. The 1400F temperature still scares me with aluminum.
Great video -- thanks! I'd like to add a couple of extra points after 15+ years of flying LOP myself: 1. Flying LOP doesn't automatically result in a power/airspeed loss. You were flying at 9,000 ft with the throttle already wide open, but if you'd been flying lower, with the throttle slightly closed, you could have increased MP slightly to make up the difference--you'd still have been LOP, but with no airspeed loss. 2. In a simpler plane like my PA-28-161 (four cylinder, fixed-pitch prop), the LOP procedure is entirely different from what you showed, and does not require an engine monitor (though it's still nice to have). As recommended by Piper, you leave the throttle wide open, then simply pull back the mixture until you get your desired RPM for your density altitude/power setting. Example: I'm at 6,000 ft density altitude (temperature-corrected), and want to fly my Warrior II at 75% power. That means that I need to fly at 2,600 rpm. I can get that RPM with many different combinations of throttle and mixture, but the most-efficient one is leaving the throttle wide open and simply lsieaning the mixture until my tach reads 2,600. That gives me around 20% fuel savings with no airspeed loss at all (at that altitude), a cooler engine, and clean plugs. :) Fortunately, 4-cylinder carbureted engines are much-more likely to fly smoothly LOP than 6-cylinder ones, because all cylinders can be equidistant from the carb.
Thanks for those comments, David. You are correct, by increasing MP one can keep power constant and save approximately one GPH (in something like my IO-520) by going LOP vs. ROP. But then on any cross country flight I cruise with the throttle wide open, so increasing MP is not really an option I have available. Regards, Martin
@@martinpauly That makes a lot of sense when you have a constant-speed prop, where high MP/low RPM is more efficient. Maybe you need another video busting the "oversquare" myth. :)
Lot's of information presented very well in a short amount of time! Great job! I discovered flying lean of peak right after I bought my Mooney M20F in 2013 and also operate the engine lean of peak most of the time. Highly recommended!
This is a great summary and demonstration of what mike busch teaches in his rather lengthy webinars. Don't get me wrong, I love his advice, but your delivery of the information is so clear and succinct.
Martin, still the best explanation on the subject. Thanks for all you are doing in educating us general aviation pilots. As a thank you, I'll send you some red paint for your mixture control. ☺ Best,
Came across this video by chance, you are obviously a very experienced pilot but also a BRILLIANT teacher. If you are an instructor your students must be the best educated pilots by far.
VERY good and informative, clear, and precise video Martin! Do more like this one...excellent! I like all your videos, very informative and good info, especially for us new pilots! I actually took the Advanced Pilot Seminar online and you just about covered it all! Since I have taken that course I have run LOP with most cruise operations. I have a Cessna 182Q with the 0-470U carbureted engine but with a belt driven Supercharger. This supercharger allows me to fly higher with more power and a nice side effect of the supercharger is being able to easily run LOP. Depending on altitude and throttle settings, my GAMI scores are around .3 to .6 and I can get to about 50 LOP. I am assuming the supercharger warms the air up like carb heat would which helps even out the fuel distribution. There is a nice and easy formula that you can use calculate your horsepower when LOP. It's based on your compression ratio. Most engines have an 8.5:1 compression so you use a factor of 14.9 (Turbo engines have a 7.5:1 compression ration which is a factor of 13.7). All you have to do is multiply 14.9 X GPH = Horsepower. In my case, I run around 10.6 to 10.9 GPH. So, 14.9 X 10.9 = 162 HP. 162/230(max HP) = 71% HP and this is all running 25 to 30 LOP! Keep in mind this formula does not work ROP. Another side effect of running cooler and leaner is less chance of plug foul, less carbon building up in the engine, and probably longer time between TBO!
Thank you, Roger. I think you may be right about the supercharger (and the warmer induction air it produces) helping with LOP - glad it works with your engine. And you are right, there are other benefits of flying LOP that I didn't cover in this video.
I do not understand English very well, but with your explanation and your very simple graphics, I understood this very easily. I have read many articles online but finally with your video I understand how to manage an engine. Thank you!
If EAA sees this video you will be doing a lecture at Air Venture!!! I have struggled understanding LOP and have been flying my BO 50 ROP. I have the same JPI monitor so it’s like you were in my plane showing. Fantastic job Martin. Have you programmed your LPI to lean find LOP? I know it’s an option. I’ll be going up with my CFI and playing with mine soon.
Thank you, Thomas. Please don't fly your Bo 50 deg ROP - now you know why not, at least not at high power settings. The JPI monitor has a "lean find" function, but I never use it. Once you know which cylinder to watch, it's easier to just go by EGT.
Was lucky to watch a similar presentation in Oshkosh this year (2021), Thanks Bonanza Society, and thanks Martin! Any updates on where one may want their CHT, when running lean of peak? (I thought you had said to stay under 400, but around 350? Is that accurate in a 1968 Bonanza… Thanks
This is an incredible video. Most instructors will show the lean procedure but never explain what is happening or why you must have the mixture setting at a certain level. After years of flying, I now understand much more about leaning and will be able to lean from intelligently than mechanically. Thank you for sharing this information. Very well done.
You can achieve the same power reduction by either (A) leaning (pull the mixture back from ROP to LOP) or (B) reducing manifold pressure (pull the throttle back). Either way you are getting more efficient (in terms of gallons of fuel per nautical mile) than before the power reduction because the resulting airspeed is lower (i.e. lower drag). Doing (A) has additional fuel efficiency on top of (B) because the same power can be produced with less fuel flow LOP compared with ROP, plus (A) also results in a cooler engine (lower CHTs) - the two main benefits of running LOP. Regards, Martin
For those wondering why a rich mixture will run with cooler EGT, there's two reasons (that I know of): 1. The fuel absorbs thermal energy when warming up and evaporating in the carburetor. A rich mixture has more fuel, thus more cooling. 2. A rich mixture combusts slower than a stoichiometric mixture. The peak temperature will therefor be lower, but because it burns so slow, it cannot transfer all of its energy into work in the piston and part of it will be lost to the valves, cylinder head, cylinder wall and exhaust manifold.
I've seen a couple of your videos in the past and never subscribed, but this made me hit the button, thanks! 11,000 hour pilot who has probably has forgotten more than I know, and this was what I needed to get back in gear.
Been running my GAMIjector equipped IO-520 LOP since 2000. Approaching 1400 hours on original Continental cylinders with good oil analysis and good compression numbers. You are spot on in your description, so I’m going to use your video for instruction. There’s still a lot of unbelievers out there. WOTLOPSOP! BTW, replacing one mag with electronic ignition made another improvement...more speed and/or less fuel.
Sensationell Video! Thank you so much from an Austrian TR182 pilot, who just upgraded to a edm 830. Happy Landings Johannes Ps: obviosly you red THE book (MB on engines) like I did…
Hallo Johannes, herzliche Grüsse aus Iowa nach Österreich! Es freut mich, dass Dir das Video gefallen hat. Damit wird Dir die Interpretation des EDM830 hoffentlich leichter fallen. Bezüglich Mike Busch: mein Video ist älter als sein Buch 😁. Mike ist relativ spät auf den "Lean-of-Peak" Zug aufgesprungen; er hat von denselben Experten wie ich gelernt: den "three amigos" des Advanced Pilot Seminars, die seinerzeit in Ada (Oklahoma) einen ganz ausgezeichneten Wochenendkurs anboten. Leider lebt nur noch einer der drei: George Braly, den Du vielleicht vom unverbleiten G100UL Flugbenzin kennst. - Martin
Lieber Martin! Das freut mich aber sehr, das Du mir antwortest, und noch dazu so schnell. Nächste Woche kommt meine TR vom ARC mit upgrade auf edm 830. ich bin schon sehr gespannt, das von Dir Gelernte umzusetzen und darauf, ob der Motor LOP kann (ist ein Turbo Lyc aber mit Vergaser). Was machst Du so weit weg? Bist Du auch from Austria? Liebe Fliegergrüsse aus Wien (LOAV) sendet Johannes
@@jonilu3473 Ich bin in Deutschland aufgewachsen, lebe (und fliege) aber schon seit fast 25 Jahren in den USA. Ein Job der Avionikfirma Collins hat mich damals hier rüber gelockt. LOP mit einem Vergaser ist Glückssache - meist klappt es leider nicht gut. Aber vielleicht hast Du ja einen der wenigen Motoren, die auch LOP ruhig laufen. - Martin
In Brazil we can t fly lean of peak. Air temperature is too high, it s hard to get lean, instead I try to fly rich of peak because it easier to avoid red box here. Thanks for the video.
Ah, but if leaning makes the CHTs too hot, then you are not lean enough! On the lean side, extra fuel doesn’t cool the engine, it makes it hotter. One of the advantages of flying LOP is a very cool engine. - Martin
Great job, very well explained! One thing I would like to add. I flew behind an IO-550 which was very happy LOP. On cross country flights it was often possible to reduce speed a little more by reducing RPM. Many times this could eliminate a fuel stop and even with the slower airspeed I would arrive at destination earlier. Not only saves time but quieter cabin at lower RPM.
You are absolutely correct, Rick. Reducing speed usually increases range, and an RPM reduction is a good way to achieve that. And if that eliminates a fuel stop, it'll actually get you to your destination moire quickly, as you said. Regards, Martin
Exceptional video. Thanks. One suggestion for users who want to get more comfortable with LOP/ROP operation. If you have X-plane 11, consider picking up one of the Carenado Bonanzas and the REP (Reality Expansion Pack) add on. The REP airplane walks you through LOP / ROP operation, warns you when you are in the "Red Box", when you are exceeding MAP limits, etc. For me, flying those airplanes made a confusing topic extremely clear and easy to understand.
Owned a Bonanza from 1990-2000. This is exactly how I flew it back then based on teachings of Mike Busch (who later wrote articles for AOPA Pilot magazine) in a VHS videotape series called ABC'S Wide World Of Flying...nice that you're helping spread the word. Love all your vids.
Martin, thanks so much for this excellent explanation. I was “raised” on ROP operation, and have been hesitant to change due to perceived risks that I now understand are not entirely accurate. Your work here, as well as further information from the folks at Continental, gives me more confidence to explore this further. Thanks again, and please keep up the good work.
@@martinpauly one question. My Baron has an Insight Gemini 1200 engine monitor. You mention that when going LOP, I should reference the LAST cylinder to reach peak. From what I can tell, this monitor only provides a “blinking bar” indication for the FIRST cylinder to reach peak. Any suggestions?
Amazing and very informative. I remember leaning 172 to the point the engine almost starving,and then quickly turning the mixture two full turns, and now I understand that there was nothing I could do about further leaning because 172 wasn't fuel injection,it has carburator. Double trouble with the Seminole when I did my twin.
Passed this on to my two partners. We fly a Turbo Arrow so there might be some differences but the explanation is so thorough and understandable (finally) that I had to share it. Thanks for posting!
Glad to hear you found this useful, Tom. In a way, a turbo-charged airplane makes things easier, because you can always act is if you were at sea level. So if you want to fly LOP, make sure you are way on the lean side, to stay outside of the red box.
Absolutely outstanding video! I’m new to this business (building an RV-10) and was somewhat confused when I heard discussions on “LOP or ROP?” This clears it up. Thank you!
In short, you can cool with fuel or air, and which costs the most and the harmonious long life of your cylinders. I learned from one of the best, and I flew a Navajo to beyond TBO without loss of one cylinder or any actual damage. But some don't get the idea. Nice job of explaining the topic. Robert
Thank you, Martin, for this excellent explanation of fuel mixture and running LoP vs RoP. I'm just learning how to fly and appreciate you're ability to explain this subject matter so clearly!
Excellent explanation from every point of view. I realized how wrong I was flying my Bonanza A36 for not understanding the mechanical part of the process
Martin Pauly an interesting topic could be the pre-flight checklist, either the outside of the plane or the inside to understand which are the critical parts to take into account. What I see is that many people (including myself) have no idea what to look at, and what it is for. Thanks again, regards
since flightsim 2020 i learned so much about aviation thanks to people like you who make these really awesome and easy to understand tutorials and lessons. thank you so much!
Martin, I came across your tail wheel training with Doug Rozendaal as I was refreshing that skill. That was great. Then looking further I found your explanation of Lean of Peak operations here. You gave such clear instruction that you have expanded my understanding of the chatter I hear from my EAA friends that have CHT and EGT monitoring in their cockpits. This is new from my general aviation experience. Thanks
Great video Martin. I took the APS seminar 17 years ago when I bought my Baron and have used GAMI's and JPI 760 to fly LOP ever since. My goal was not only economy but trying to be "nice" to my engines to put off the expensive overhauls... Since then, I have also read John Eckalbar's book, "Flying High Performance Singles and Twins". He has some great analysis (with more math than most would like) about efficiency and range. Your video shows us the result of that with the mpg readout on the jpi. The combination of burning more air and less fuel combined with the slower IAS is a win win for range enhancement. As a real life experiment, I flew my Baron LOP at 13k ft maintaining aprox 140 kts IAS (very slow and extremely patient) all the way from WI to east central FL. Took a little more than 6 hours but had >2 hours of fuel left in the tanks. Could have continued to Key West! Way more than the POH tables from 1970 would have allowed even at best economy. That said, in the spirit of academic skepticism, the analysis you present about fuel savings to TBO might be unfair because we generally fly to destinations vs. for hours flown. If by flying LOP we take longer to fly there, we use more of our hours toward TBO and cannot claim the gallons per hour savings as real. However, if by flying LOP, we extend our TBO time (on condition), then it holds up fine. My experience has happily been that although I can't prove that 2500 hours at lower CHT is why I was able to do that. One comment that one of the APS guys made that has stuck in my mind is that if we still want to go fast (Bo's and Baron's like to do that), stay at a sweet altitude 7-9k, bring the rpm's up, sacrifice some fuel economy but stay LOP -keeps the cht's down, and brings the airspeed back up that 8-10 kts that you saw was lost on your flight. Have you tried that? Keep up the great videos! David
Thanks for the feedback, David. You are right in that the fuel savings analysis was very simplified and only looked at one at of many possible angles. Extending the life of the engine is a big factor, but how do you make generally valid assumptions over how many extra hours you get? In order to avoid getting overly subjective, I tried to keep this part of the video plain and simple - even knowing my analysis was not complete. Best regards, Martin
Hi Martin, Awesome explanation, thanks for taking the time. I'm also curious about the fuel savings "at the same HP output" as David implied above. this could be by either taking up the RPM to get back to speed, or by staying ROP and lowering MP to get to the LOP speed. I do fully understand the other benefits to LOP but I'm curious how close the fuel burn would be at the same output ROP. This question also helps those not running constant speed as they don't have the same level control over all the inputs to get the desired outcome.
Hi Steve, GAMI has determined that in their engine test stand. Refer to this image: www.gami.com/img/gamijectors/test_results/tritcm1.gif Looking at the center and the right portion, there are two power settings for the same engine (with GAMIjectors in both cases) producing the same HP output, 196 HP or 65%. The difference is the center image represents 23" of manifold pressure while 25 degrees ROP, while the right image represents 24" MP while 25 degrees LOP. So the higher MP while LOP offsets the power reduction from running lean of peak, to get back to the same horsepower. The savings here from LOP are one GPH (12.5 vs. 13.5), which is generally accepted as the portion of the savings coming from running LOP, as opposed to savings from flying slower. Best regards, Martin
Martin, thank you so much for the gracious reply... I realized the answer was in another comment I hadn't read yet. Sorry about that. Another question is regarding the red box size. Is this literally determined by the range of unacceptable CHT's? I'm asking in regards to any leaning with a turbo (usually at higher than 65% power)?
Steve, that (range of unacceptable CHT's) is not a bad way to think of it. One thing I should point out, unlike what the graphics in the video suggest, the red box doesn't have a sharp, clear boundary - more like shades of pink. With a turbocharged engine at higher power settings, you will have to be more lean when LOP (and more rich when ROP) compared with low power settings.
On my RV7 not only did I run the engine almost exclusively LOP (in cruise) I also ran autofuel. The problem of course with autofuel is potential vapour lock on a low wing airplane. For this reason my IO360 did not have a mechanical fuel pump, it dual redundant electrical fuel pumps instead. Never had any problems over 500 hours and the borescope showed a completely clean engine when I sold it.
Thank you for the kind words. Mixture management is not really a difficult subject, but one that gets little or no attention during primary training. Regards, Martin
I see your point; as a renter paying a wet hourly rate, you might as well go in fast mode (i.e. ROP). Having said that, if you can stretch your range so as to avoid a fuel stop on a cross country flight, flying LOP may still save you time and money. - Martin
Martin, really, really good video - thank you for making it. The one issue I see, and it is certainly not a fault with your theory or practice, is that most club aircraft have one single crappy EGT gauge that takes about 5 minutes to react to mixture changes. I on that basis have refrained from leaning out normally aspirated engines, because the feedback on how the engine is feeling in reaction to the mixture leaning just isn't quick enough to give me confidence that I am far enough LOP to be out of red box territory in a timely manner. I did however fly a TIO540 engined aircraft for a short while, and the aircraft was fitted with an EDM800. What a fantastic improvement this was. in VMC at least, it was the best instrument in the cockpit by far. The turbo aircraft do need much more careful management of mixture, and given the near-instantaneous per-cylinder information the EDM gives the pilot, correct mixture control was possible. I say possible, because unless you are an instructor with a few thousand hours on the specific aircraft, leaning mixtures based on the crappy EGT gauge most club/school hacks have in them is risky business, impossible even. I don't know why more flying syndicates don't fit EDMs in their a/c - OK its a couple of thousand dollars I think, but what price engine rebuild? If its a TIO540, about £50k...
Thanks for your comment, Edward. I agree the engine instrumentation of your typical flying club airplane leaves a lot to be desired. And from what I have seen, that probably matches the level of knowledge and understanding of engines management that most pilots have who fly these airplanes. 😁 And to be honest, for beginner pilots and the trainer aircraft they typically fly that's probably OK. There is so much to learn that an in-depth understanding of engine operation is probably too much to ask. But when pilots step up to high-performance aircraft with more powerful engines, that understanding and the instrumentation necessary to apply it become a lot more important. A TIO540 is a lot easier to damage from wrong operation than an O320. A modern digital engine monitor will pay for itself quickly in these airplanes. Kind regards, Martin
Unbelievable video. I fly a 1980 A36 (520) and have really been perplexed by running lean of peak the last couple years. Thank you for this! Exactly what was needed!
This is heresy I tell ya! Leaner Always means hotter...so they taught me... Its black magic. Great presentation and loved all your sensors verifying the conditions. This must be how Lindbergh taught the P-38 guys how to significantly increase range and the engines showed no damage from being lean. Thank you, great job.
Thank you. And you are right, LOP is not new, it was the normal way to play back in the day of piston engine airliners. It was how they got the range they needed.
I've never been involved with aviation in any way but my daughter is starting Parks college in the fall to become a commercial pilot, so I'm taking an interest in this stuff to be able to converse with her about her licensing and aviation path. It's interesting to see in the comments how few pilots understand engine theory. I've restored classic Chevys and built high performance Chevy engines for 40 years, and this theory is extremely basic and straight forward, yet seems to be black magic to many. This video should help clarify this theory. Well done.
Thank you. I agree, engines aren't rocket science. In the early days of aviation, when piston airlines traveled across oceans, these piston engines were better understood by many pilots than today, it seems. In fairness to pilots: there is A LOT to learn to earn a pilot certificate, and engines and engine management are only one of many, many topics. I would also say that the average trainer aircraft these days has a rather forgiving and robust engine, and it's hard to damage them through improper operation. But when pilots step up to high-performance piston airplanes, engine management becomes a lot more important, and I hope this video helps them become better prepared to treat their previous engines well. - Martin
Along with the many praises you've gotten here, I will say excellent job. Mike Busch has also done a very good job of describing the "big pull" I haven't yet watched a John Deakins presentation. I have had a JPI gauge for several years and now have a Garmin GI275. They say you need to lean slowly to watch the temperature rise come to a peak. This puts one in danger of dwelling in the Red Box for too long, and doesn't seem like good advice, but it's what you get when you buy the gauge. I'm glad you and Mike have provided clarification. I like your suggestion of determining peak EGT from the lean side after doing the big pull. Other advice has just said do the big pull and then settle on a desired fuel flow or EGT?? I don't know which, but I like the idea of knowing where peak sits and then being able to lean from that a desired amount of degrees. Now I have to go out and practice and find my last cylinder to peak. I mostly operate at 65% power so shouldn't have to worry about the red box, but sometimes want to operate at higher power. By the way, with the GI275 I have a power readout and that is an option in gauges from JPI and EI, so it's becoming much more common now to have a direct percent power readout. I do wonder hwo accurate it is?
Martin, I watched this video before but now it has proven more beneficial now that I just got a new Dynon HDX with the engine monitors. Thanks for sharing!
wow this is awesome! very very well made. it couldn't be more true that being able to teach someone about a certain topic means you have really mastered whatever that topic is.
Excellent video Martin ! "Baron Pilot" recommended this and he was right. I spent many years in a 58 Baron, with performance conversions on the engines. I understand the mixture, temp and power settings much better now, than then. Especially the "why" questions. You did a great job in simplifying this. Thank you for sharing this valuable information. Safe skies !
This helped me allot. Two new overhauls coming for my PA-30 this month. I added an EDM 760 and LOP has been recommended. Very nice resource for me to keep coming back to. Thank you!
I also have a PA30 with a EDM760! Haven’t tried flying lean of peak much yet, have just been following the POH power tables for flying at either peak or 50-100° rich depending on power. What kind of CHT temps are you seeing during LOP operation? Do you find the fuel economy to improve from the best economy (peak) recommendations in the POH?
Alex1911 I’ve only tested it thus far. Next flight will implement it. Expecting 7-7.5 gph. Smooth operation all the way down to 5.7, getting cooler as you lean. I’ll report longer runs with more valid ops data. I’m curious about the TAS
Frank Dorrin yeah that’s what I’m interested in since the POH says best economy is at peak. But I’m guessing they didn’t test LOP operations since the plane wasn’t originally equipped with an engine monitor. Let me know what you find in your experimentation! I’ll do some testing on Monday if the weather is good. I also take everything in the ICS POH with a grain of salt since it’s full of errors. Like the starting procedure which leaves the fuel pump on as if it were an O-320 vs an IO-320, not mentioning feather in the engine fire procedures, leaving the mixture cut off and fuel shut off in intentional single engine ops, and their backwards engine failure procedures that call for drag before power.
Lovely job, Martin! I operate my Lancair 360 LOP (lucky to be able to do it since it's not injected). The biggest challenge is to not fixate on ONE cylinder, but to identify which cylinder is last to come to the LOP party. In other words, it's quite possible to have 3 cylinders 25LOP while the last remaining cylinder is still ROP. This manifests itself with high CHTs on the last cylinder. I keep leaning until ALL the EGTs are coming down. Basically, once I see one EGT drop, I ignore that cylinder and keep watching the others. Eventually there's only one left, and that is what I use to gauge where I am on the curve from that point forward. Of course, by the time IT starts playing ball, the other 3 cylinders are further along the lean side, producing less power, and you can end up with some vibration. It's a tough balancing act, and is the reason that most carb engines can't run lean of peak. Balanced injectors make things a LOT easier once they're setup correctly, but thankfully, I've made it work with my Lancairs. ROP the CHT's will be 420+ for me. LOP they're around 350-360. TAS goes from 197KTAS ROP to around 190KTAS LOP with approx 20% fuel savings, just as you demonstrated.
Thanks for the feedback and comment, coma13794. Your description of your leaning process is spot on, and I am happy to hear LOP works as well as it does with your carbureted engine. Nice!
Martin, as a retired NASA astronaut, space shuttle captain, and SR-71 owner for 20 years, I have to say I'm impressed with your ability to explain how to lean a piston engine in only half an hour. Good job and THANK YOU for making such quality content!
I appreciate the kind words. I do have one question for you: how does one become an SR-71 owner? (Other than being a tax payer)
Best regards,
Martin
Hmmm...SR-71 "owner". NOT! Also, space shuttle "captain". NOT! Anyone familiar with Shuttle crew knows that the term is Commander...never Captain.
😆
woosh
@martinpauly I think this was said in humour....because of all the other people replying and quoting their resumes. Like any of that has anything to do your video....
Martin, as a military and professional airline pilot with over 27,000 hours, as well as Bonanza owner of fifteen years, I have to say I am impressed again with your ability to explain often confusing topics in simple terms. Nicely done and keep up the fine work!
Thanks, Bruce - I appreciate the kind feedback. There are a lot of misunderstandings and myths about mixture management when in reality it is not such a difficult topic.
- Martin
Martin, as both an aerospace engineer and a retired USAF Navigator (responsible for both preflight fuel calculations as well as enroute fuel management), I wholeheartedly endorse your video! You not only nailed the issues solid, but you covered the exceptions in a clear and notable manner. EXCEPTIONALLY well-done!
Thank you very much for the encouraging feedback, Justin. Much appreciated.
cok
I could not agree more...but I am far from a aerospace engineer! haha Great video Martin!
In my days, the copilot did all the fuel calculations and managed the inflight fuel management, not the Nav.
Had Martin been my professor for thermodynamics I probably would have stayed in engineering 20 years ago. Thermodynamics is hard enough without it being explained in a broken chinese accent!
Martin, as a retired captain of starship enterprise ,a NASA astronaut, space shuttle captain, and SR-71 owner for 20 years, I have to say I'm impressed with your ability to explain how to lean a piston engine in only half an hour. Good job and THANK YOU for making such quality content!
Last time you posted almost this exact comment you were "Virtualmix". I am still curious how one becomes an SR-71 owner (other than being a taxpayer). But I appreciate the kind words on this video!
- Martin
Here are some words from an old CFI who soloed in 1965: "Your video is stunningly brilliant!!" I wil make this mandatory for any future student and recommend others do the same. Thank you very much!!
Thank you for the encouraging feedback!
- Martin
I fly for 30 years and never understood this topic completely, it is often explained by experts with no didactic skills. I completely understand now. Thank you so much for your talent and skills to teach!
Glad I could help!
- Martin
Wow! Despite having many people, including my mechanic trying to explain me Lean of peak, I never got to fully understand.
But thanks to your video, now I can feel safe using lean of peak
It's really not that difficult a topic, is it?
Probably feels scarier than it is to most pilots.
- Martin
Martin, hopefully, you don't get tired of praise. With 10 years flying fighters in the Marines, and 25 years as an airline pilot, I've had my share of flying "lessons"! This was the best, most concise, most helpful video ever. You have a gift, Sir! Thank you for taking the time to produce this! It should be part of every GA pilot's education!
Thank you very much for the kind words, Logan. It means a lot coming from someone with your background.
Regards,
Martin
Hey Martin, GREAT video. Probably the best video I have ever seen on the topic. I am going to bring up the topic in a video and refer my viewers to this video for a better explanation.
Thank you, Baron Pilot - much appreciated!
And Martin, I just watched the video since Baron Pilot suggested it, and it reinforces all I thought I knew about LOP operations, and added additional information. Very well done, very easy to understand, and very informative.
Thank you for the feedback, Gary. I am glad you found it useful.
What a great lesson. Most folks can’t describe much less define how to lean an engine and why it matters. Your video makes it very clear why it matters.
Thank you for the kind words, Ed.
- Martin
You are a fantastic teacher! Pretty good video editor too. First rate educational material.
Thank you, John! It's been fun making and editing this video.
Martin, as the undercover persona of BuzzLightyear, with over 257,000hrs of intergalactic missions, I am impressed by your explanations. Keep up the good work. To infinity and beyond!
That's quite an endorsement coming from Buzz Lightyear! 🤣
Thanks,
Martin
I don't even fly and I found this presentation completely understandable. Very interesting and well done.
Thank you, Rob. Glad to hear you found it useful.
- Martin
Hi Martin, I was at an aviation maintenance conference today. My vendor booth was next to the Lycoming booth. A mechanic visiting the Lyc booth and asked the representative what he thought about lean of peak vs rich of peak. The rep was struggling for an answer. I had just watched this video earlier in the week so I interrupted them both and urged them to watch your video which I still had queued up on my iPhone. The mechanic was looking for the "one size fits all" answer and I explained to him that after watching your presentation he would understand there isn't one due to many inter-relating factors. Both were very impressed with your explanation and learned a lot. Especially the Lycoming rep. He later told me he had never seen it so clearly explained. Great job! I worked for an engine accessories manufacturer; fuel systems, turbochargers, wastegates, starters, etc. for years and it was the best I've seen too. Thank you!
Thank you for spreading the word on LOP, and on this video. It sounds like this topic is still a mystery to many.
I'll be at Sun 'n Fun this year, and will give a couple of presentations on this topic.
Best regards, Martin
@@martinpauly My company exhibits at Sun n Fun each year. Perhaps I'll be able to sit in on one of your presentations. Good luck with it. I'm sure it will be well received. Best--
Despite reading several articles on the subject, I never really understood the mechanics behind the decision process. Very good explanation that shows a superior depth of understanding - BRAVO!
Thank you very much, Dave. I'm glad you found it helpful.
Mr. Pauly knows how to breakdown complicated jargon into simple terms so most everyone can understand what is going on. That is a valuable skill set in any vocation. Impressed.
Thank you, Anthony - I appreciate the kind feedback!
- Martin
Absolutely on of the best videos summing up engine management! Great work!
This is by far the best technical and practical explanation of ROP/LOP that I have ever seen.
Thank you, glad to hear.
- Martin
Excellent discussion and teacher. I am reminded of my automotive racing days with normally aspirated carbureted engines. I loved the challenge of setting up an engine with various fuel flows, jets, and cam angles for the best performance of the day. This was all before fuel injection. It was fun and I learned a lot. I had to set up my own gauges inside the car for manifold pressures, EGT, and CHT. The science was fascinating! Thanks, Martin!
Thank you for the kind words, Rich. Yes, engines are fascinating, aren't they?
- Martin
I've been flying my Bonanza for a year, and this was the most informative and clear explanation I've seen regarding the financial and performance impacts of LOP vs. ROP. Highly recommended for any pilot, especially if you own the plane. I will now spend most of my life at LOP, with confidence.
Thank you, Clay. Happy to hear you found the explanation useful. Welcome to the lean side of peak! 👍
- Martin
@@martinpauly Thank you, Martin. I look forward to checking out your other videos.
Martin, thank you so much for this video. I have tried to understand LOP from several sources, leaving a lot of questions behind. You explained it so simple and now I finally know what´s going on and how to deal with the airplanes I am flying. Also I love the way you explain and show examples on the instruments and charts.
Thank you !!
You are very welcome - glad to hear it was helpful.
- Martin
Martin is an exceptional teacher an Areo Guru award is in order.
This is a terrific video Martin. I wish more people would make videos as comprehensive as you have. This is a true reference resource. I know how much work it is to make this happen, so many thanks to you! And, by the way, thanks for recently accepting my invitation on LinkedIn. All the best, Josh
Thank you for the kind words, Josh.
Regards, Martin
I'm not a pilot but I watch a lot of Aviation videos. I like that you're humble enough to include some out takes. I think it earns you more respect.
Thanks, Don. It takes a lot of trying until we get something polished. I thought the outtakes at the end would be entertaining.
Best, Martin
Great video! Thank you for putting this out there
Thanks for the feedback, TFP. Glad to hear you liked the video.
Martin,
As a space shuttle owner and developer of the first, abnormally aspirated piston aircopterjet, I too am impressed with the clean and clear instruction and demonstrations. I can’t learn anything until I understand the how and why. Thank you for making it more clear. New subscriber!
Great video explanation, Martin. I'm an instructor in a flying club and will be sharing this as required reading.
Thanks - glad to hear you think the video is helpful!
´ve been flying for 40 years , but has NEVER hed the problem adressed as neat and clear as you managed . Thanks and regards from Denmark !
Thank you for the kind feedback, Arne.
Greetings from Iowa!
- Martin
One of the most informational videos I have ever seen on UA-cam! Great job! Outtakes were classic.
Thank you, Robert - I'm happy to hear you found it useful.
- Martin
Thanks for sharing...... Im a pilot that flew a lot of turboprop and turbines ,and now I will start piston engines.......
It is new for me and Im learning a lot from you.Congrats! 👍👍
I almost quit watching at "Hello Bonanza Fans" It was hard to get past that part.
I pressed on however. Outstanding Info. Subscribed.
Just Plane Silly Hey Bryan, I’m glad you were able to make it past the word “Bonanza” - I know, it’s hard to be a fan of an airplane in which pilots practice slow flight at the taxi speed of a Cirrus. :-)
Thanks for chiming in; I love your videos!
HAHAHAHAHA!!!!!!! Thank you!
I have already shared this video with a handful of people.
Very well done and very well simplified.
If you go to Osh this year, let me know. I will buy you a beer!
How could I turn down a beer - thank you!
I don't know yet if I'll be in Oshkosh this year. If I go, it'll be at the end of the event, because it is the same week as RAGBRAI, a cycling event (which is really just an athletic euphemism for "weeklong party on bikes") here in Iowa - so I am torn, and RAGBRAI usually wins.
At any rate, I do hope to run into you one of these days somewhere.
Just not in the air.
@@martinpauly I just hit the like button. Actually Bryan is a changed man 😂 He seems to be creating some sort of a promotional video for the Bonanza one of these days.
I'm a private pilot and this is one of the best explanation on Lean of Peak
Excellent video... By far the best video on this topic.
Thank you, Steven.
In all my years on UA-cam, this is the first time i've commented on a Video. Thankyou so very much for your clear, informative and demonstrated video. You cured my headache on LOP in the first 10 mins.
Thank you for the feedback, Sir. Glad to hear this video has helped you make sense of LOP.
- Martin
Well done, Martin. I've been an advocate of LOP for many years, and your explanation is better than I could have done. My Cessna 421B has used LOP for the 40 years I've owned her, and the big GITSO 520s always make it well beyond TBO.
PS: Loved the outtakes.
Thank you, Raymond.
Regards, Martin
This is by far the best tutorial on engine leaning i have come across. I've talked to several CFIs and flying friends, and watched several UA-cam videos. But this one video breaks everything down into small bites of common language explanations that is so easy to follow. Thank you!
Thanks for the kind feedback, Tuan. Mixture management is not really all that complicated, but collectively in the aviation world we don't seem to do a good job teaching it - so a lot of misunderstanding and myths exist. That's what I was hoping to help with through this video.
Best regards, Martin
How do you have manage to do such a great job on these and still have a real job? All your videos are first class.
Thank you, David.
Making videos is just a hobby, and very different from my day job. Maybe that's one reason I like it so much - a welcome change from the office chores.
I've been looking at this subject for several weeks now and have read most of John Deakins' articles on Pelican's Perch, but I have to say that his video was the most lucid and well laid-out distillation of this complicated subject that I've seen anywhere. Really excellent. Thank you very much.
Thank you for the kind words.
- Martin
Hi Martin, this was by far the best from all other videos I have watched regarding the topic. Thank you.
Thank you, Abraham. Glad you liked it.
Martin, this is a fantastic video. When I first got my Mooney Acclaim I took it to a renowned Mooney expert up in Minnesota to learn how to operate LOP, which I had never done before. He gave me pretty much this exact same presentation and I know it has saved me lots of $$$ and engine wear over the past 6 years. Bravo, and thank you!
Thank you, First Last - glad you like the video.
With electronic ignition you can take even more advantage of LOP. The LOP robs the engine of power since the combustion charge burns more slowly and the piston has already started "down" from top dead center by the time you have full burn of the combustion charge. With electronic ignition you can change the ignition timing, advance the spark, and return to full combustion closer to top dead center on the piston. This gives you more power out of the fuel you are burning and even more economy.
That's correct. It's a shame we don't see electronic ignition being used more widely in piston GA airplanes.
Regards, Martin
@@martinpauly As electronics engineer I full agitate against unnecessary complication when goal may be achieved witch simpler solutions. Magnetos are highly reliable, cheap and easy to maintenance. Electronics improve efficiency but is more prone to malfunction. OK, as most of systems in aviation should be redundant as magneto is (two independent systems on cylinder). Next problem to solve is powering, magnetos works autonomously but electronic ignition depends on external electricity. More points to probable failure for electronic - from engine shaft sensor/actuator, by wiring, connections to spark module at end - less trustworthy system for pilot than simple magnetos, even with more fuel cost. Life is priceless.
Best on this topic I've seen so far. I'll just add that I have a set-up that operates on aircraft without electrical systems that does the same thing; I use dual EGT and CHT gauges stacked so that the needles are laid out like the engine- two dual EGT needles with the top set for the forward cylinders and the bottom set for the rear cylinders; same with the two dual CHT gauges. These are inexpensive Westachs. In cruise, Wide Open Throttle (at altitude), a glance tells you things are good when all the opposing needles point at each other. And initially the front right CHT was low; an additional baffle brought it up so now all the CHTs are matched. I can now lean confidently in an airplane with no electrical system, which is very satisfying.
That sounds like a good setup of gauges in your aircraft, Craig.
- Martin
@@martinpauly It's a real comfort in flight to see those needles behaving. You can also see those CHTs come down across the board as you continue to lean past peak EGT- I never trusted rotary switches to select probes (it doesn't take much noise in switching to throw those faint currents off), so having the baffling right and seeing even temps all through the leaning procedure is a real confidence builder. You don't have to do anything but manage mixture and power and just glance over to see what is going on.
I typically take off full rich/full power and then when I turn crosswind I make a power reduction to the bottom of the green arc on the tach, then lean back up to the middle of the green. Then as I cruise climb I repeat that after a minute or two by leaning slightly out the bottom of the green and bringing it back by advancing the throttle.
After 4 or 5 gentle iterations, I'm at Wide Open Throttle, at about 7000' of DENSITY altitude, and nicely stabilized at the Norris Point, or 1.316 times max ROC IAS. With a C-85 I'm burning less than 4 GPH. I do have a forbidden RPM band with a McCauley Klip-Tip prop, so dancing around that green arc on the tach is a low stress procedure (well away from the forbidden band) and especially because the temps are in friendly territory.
These are 2" instruments clustered in not much more space than a single 3" instrument. I'm converting every airplane I own to this setup. And again- no electrical system required.
The best video on Mixture Leaning I've ever seen. Thanks a lot !!!
Merci beaucoup!
- Martin
Clear and concisely explained. Thank you. I used to tune carbureted two stroke racing motors. Lean was bad due to the cooling factor of the fuel. Your 4 cycle tuning chart, backed up by actual demonstration makes all the sense in the world. The 1400F temperature still scares me with aluminum.
Absolutely the BEST video on running LOP!!! Congratulations Martin... und ja...vielen Dank !
Thank you very much!
- Martin
Great video -- thanks! I'd like to add a couple of extra points after 15+ years of flying LOP myself:
1. Flying LOP doesn't automatically result in a power/airspeed loss. You were flying at 9,000 ft with the throttle already wide open, but if you'd been flying lower, with the throttle slightly closed, you could have increased MP slightly to make up the difference--you'd still have been LOP, but with no airspeed loss.
2. In a simpler plane like my PA-28-161 (four cylinder, fixed-pitch prop), the LOP procedure is entirely different from what you showed, and does not require an engine monitor (though it's still nice to have). As recommended by Piper, you leave the throttle wide open, then simply pull back the mixture until you get your desired RPM for your density altitude/power setting.
Example: I'm at 6,000 ft density altitude (temperature-corrected), and want to fly my Warrior II at 75% power. That means that I need to fly at 2,600 rpm. I can get that RPM with many different combinations of throttle and mixture, but the most-efficient one is leaving the throttle wide open and simply lsieaning the mixture until my tach reads 2,600. That gives me around 20% fuel savings with no airspeed loss at all (at that altitude), a cooler engine, and clean plugs. :) Fortunately, 4-cylinder carbureted engines are much-more likely to fly smoothly LOP than 6-cylinder ones, because all cylinders can be equidistant from the carb.
Thanks for those comments, David. You are correct, by increasing MP one can keep power constant and save approximately one GPH (in something like my IO-520) by going LOP vs. ROP. But then on any cross country flight I cruise with the throttle wide open, so increasing MP is not really an option I have available.
Regards, Martin
@@martinpauly That makes a lot of sense when you have a constant-speed prop, where high MP/low RPM is more efficient. Maybe you need another video busting the "oversquare" myth. :)
Lot's of information presented very well in a short amount of time! Great job! I discovered flying lean of peak right after I bought my Mooney M20F in 2013 and also operate the engine lean of peak most of the time. Highly recommended!
Thanks, Bernd - or should I say "Danke"?
Whatever pleases you... - I'm current and Level 6 in both languages... ;-)
This is a great summary and demonstration of what mike busch teaches in his rather lengthy webinars. Don't get me wrong, I love his advice, but your delivery of the information is so clear and succinct.
Thank you - it must be "German efficiency" 😀
- Martin
Martin, still the best explanation on the subject. Thanks for all you are doing in educating us general aviation pilots. As a thank you, I'll send you some red paint for your mixture control. ☺ Best,
The red paint comment made me laugh! :-)
Thanks, Dennis.
- Martin
Came across this video by chance, you are obviously a very experienced pilot but also a BRILLIANT teacher. If you are an instructor your students must be the best educated pilots by far.
Thank you for your vote of confidence. Yes, I am a flight instructor, though I think your prediction goes a bit too far. 😁
Regards,
Martin
VERY good and informative, clear, and precise video Martin! Do more like this one...excellent! I like all your videos, very informative and good info, especially for us new pilots! I actually took the Advanced Pilot Seminar online and you just about covered it all! Since I have taken that course I have run LOP with most cruise operations. I have a Cessna 182Q with the 0-470U carbureted engine but with a belt driven Supercharger. This supercharger allows me to fly higher with more power and a nice side effect of the supercharger is being able to easily run LOP. Depending on altitude and throttle settings, my GAMI scores are around .3 to .6 and I can get to about 50 LOP. I am assuming the supercharger warms the air up like carb heat would which helps even out the fuel distribution. There is a nice and easy formula that you can use calculate your horsepower when LOP. It's based on your compression ratio. Most engines have an 8.5:1 compression so you use a factor of 14.9 (Turbo engines have a 7.5:1 compression ration which is a factor of 13.7). All you have to do is multiply 14.9 X GPH = Horsepower. In my case, I run around 10.6 to 10.9 GPH. So, 14.9 X 10.9 = 162 HP. 162/230(max HP) = 71% HP and this is all running 25 to 30 LOP! Keep in mind this formula does not work ROP. Another side effect of running cooler and leaner is less chance of plug foul, less carbon building up in the engine, and probably longer time between TBO!
Thank you, Roger. I think you may be right about the supercharger (and the warmer induction air it produces) helping with LOP - glad it works with your engine.
And you are right, there are other benefits of flying LOP that I didn't cover in this video.
I do not understand English very well, but with your explanation and your very simple graphics, I understood this very easily. I have read many articles online but finally with your video I understand how to manage an engine.
Thank you!
Glad I could help, Alessandro.
And from what you wrote, your English seems to be quite good!
Regards, Martin
If EAA sees this video you will be doing a lecture at Air Venture!!! I have struggled understanding LOP and have been flying my BO 50 ROP. I have the same JPI monitor so it’s like you were in my plane showing. Fantastic job Martin. Have you programmed your LPI to lean find LOP? I know it’s an option. I’ll be going up with my CFI and playing with mine soon.
Thank you, Thomas.
Please don't fly your Bo 50 deg ROP - now you know why not, at least not at high power settings.
The JPI monitor has a "lean find" function, but I never use it. Once you know which cylinder to watch, it's easier to just go by EGT.
Only fly that way at cruise, full rich for climb. I noticed you leaned at 2500 RPM, is that where you fly?
Yes, for cruise and descend - that seems to be a happy place for my engine. For take-off and climb, I run at 2,700 RPM.
Was lucky to watch a similar presentation in Oshkosh this year (2021), Thanks Bonanza Society, and thanks Martin! Any updates on where one may want their CHT, when running lean of peak? (I thought you had said to stay under 400, but around 350? Is that accurate in a 1968 Bonanza… Thanks
This is an incredible video. Most instructors will show the lean procedure but never explain what is happening or why you must have the mixture setting at a certain level. After years of flying, I now understand much more about leaning and will be able to lean from intelligently than mechanically. Thank you for sharing this information. Very well done.
How is the net result of leaning different than just reducing the manifold pressure or throttle?
You can achieve the same power reduction by either (A) leaning (pull the mixture back from ROP to LOP) or (B) reducing manifold pressure (pull the throttle back). Either way you are getting more efficient (in terms of gallons of fuel per nautical mile) than before the power reduction because the resulting airspeed is lower (i.e. lower drag). Doing (A) has additional fuel efficiency on top of (B) because the same power can be produced with less fuel flow LOP compared with ROP, plus (A) also results in a cooler engine (lower CHTs) - the two main benefits of running LOP.
Regards, Martin
For those wondering why a rich mixture will run with cooler EGT, there's two reasons (that I know of):
1. The fuel absorbs thermal energy when warming up and evaporating in the carburetor. A rich mixture has more fuel, thus more cooling.
2. A rich mixture combusts slower than a stoichiometric mixture. The peak temperature will therefor be lower, but because it burns so slow, it cannot transfer all of its energy into work in the piston and part of it will be lost to the valves, cylinder head, cylinder wall and exhaust manifold.
24:58 S.T.F.U. Made me laugh out loud!
Yup. Everybody likes outtakes. :-)
Martin, This perhaps the best basic explanation of LOP operations I have seen. Nicely done!
Thanks, Bruce. Glad to hear you found it useful.
Regards, Martin
My God... I've had 20,000 people try to explain this to me, and you finally made this completely understandable. Thank You!
Thanks, hawkdsl - glad to hear it was helpful for you.
This video training tutorial should be viewed by pilots, mechanics and everyone else in out business.
Thanks, Phillip.
- Martin
This is an excellent video that combines graphs and practical operations in how and why LOP works.
Well done!
Thank you! 😁
- Martin
I've seen a couple of your videos in the past and never subscribed, but this made me hit the button, thanks! 11,000 hour pilot who has probably has forgotten more than I know, and this was what I needed to get back in gear.
Been running my GAMIjector equipped IO-520 LOP since 2000. Approaching 1400 hours on original Continental cylinders with good oil analysis and good compression numbers. You are spot on in your description, so I’m going to use your video for instruction. There’s still a lot of unbelievers out there. WOTLOPSOP!
BTW, replacing one mag with electronic ignition made another improvement...more speed and/or less fuel.
Thanks, Manny.
WOTLOPSOP it is!
Regards, Martin
Sensationell Video! Thank you so much from an Austrian TR182 pilot, who just upgraded to a edm 830.
Happy Landings
Johannes
Ps: obviosly you red THE book (MB on engines) like I did…
Hallo Johannes, herzliche Grüsse aus Iowa nach Österreich!
Es freut mich, dass Dir das Video gefallen hat. Damit wird Dir die Interpretation des EDM830 hoffentlich leichter fallen.
Bezüglich Mike Busch: mein Video ist älter als sein Buch 😁. Mike ist relativ spät auf den "Lean-of-Peak" Zug aufgesprungen; er hat von denselben Experten wie ich gelernt: den "three amigos" des Advanced Pilot Seminars, die seinerzeit in Ada (Oklahoma) einen ganz ausgezeichneten Wochenendkurs anboten. Leider lebt nur noch einer der drei: George Braly, den Du vielleicht vom unverbleiten G100UL Flugbenzin kennst.
- Martin
Lieber Martin!
Das freut mich aber sehr, das Du mir antwortest, und noch dazu so schnell. Nächste Woche kommt meine TR vom ARC mit upgrade auf edm 830. ich bin schon sehr gespannt, das von Dir Gelernte umzusetzen und darauf, ob der Motor LOP kann (ist ein Turbo Lyc aber mit Vergaser).
Was machst Du so weit weg? Bist Du auch from Austria?
Liebe Fliegergrüsse aus
Wien (LOAV) sendet
Johannes
@@jonilu3473 Ich bin in Deutschland aufgewachsen, lebe (und fliege) aber schon seit fast 25 Jahren in den USA. Ein Job der Avionikfirma Collins hat mich damals hier rüber gelockt.
LOP mit einem Vergaser ist Glückssache - meist klappt es leider nicht gut. Aber vielleicht hast Du ja einen der wenigen Motoren, die auch LOP ruhig laufen.
- Martin
In Brazil we can t fly lean of peak. Air temperature is too high, it s hard to get lean, instead I try to fly rich of peak because it easier to avoid red box here. Thanks for the video.
Ah, but if leaning makes the CHTs too hot, then you are not lean enough! On the lean side, extra fuel doesn’t cool the engine, it makes it hotter. One of the advantages of flying LOP is a very cool engine.
- Martin
Do you not have the same atmosphere where there is the standard lapse rate?
Great job, very well explained! One thing I would like to add. I flew behind an IO-550 which was very happy LOP. On cross country flights it was often possible to reduce speed a little more by reducing RPM. Many times this could eliminate a fuel stop and even with the slower airspeed I would arrive at destination earlier. Not only saves time but quieter cabin at lower RPM.
You are absolutely correct, Rick. Reducing speed usually increases range, and an RPM reduction is a good way to achieve that. And if that eliminates a fuel stop, it'll actually get you to your destination moire quickly, as you said.
Regards,
Martin
After watching this Great video, my newly purchased 2016 Bonanza G36 will be flown a whole lot different from now on. Thanks Martin...
Ken, glad to hear you got something useful out of the video - and congrats on the G36!
- Martin
The BEST video ( I've seen so far ) explaining Lean of Peak vs Rich of Peak !!!! Very well done Sir !!
Thank you, Omar.
- Martin
Not a pilot here. But you've explained this in a way that I can understand. Thanks for your effort. Subscribed.
Happy to hear it was easy to digest this!
Best, Martin
Exceptional video. Thanks.
One suggestion for users who want to get more comfortable with LOP/ROP operation. If you have X-plane 11, consider picking up one of the Carenado Bonanzas and the REP (Reality Expansion Pack) add on. The REP airplane walks you through LOP / ROP operation, warns you when you are in the "Red Box", when you are exceeding MAP limits, etc. For me, flying those airplanes made a confusing topic extremely clear and easy to understand.
That's good to know - thank you for sharing!
- Martin
Owned a Bonanza from 1990-2000. This is exactly how I flew it back then based on teachings of Mike Busch (who later wrote articles for AOPA Pilot magazine) in a VHS videotape series called ABC'S Wide World Of Flying...nice that you're helping spread the word. Love all your vids.
Thank you very much!
Phenomenal presentation. I really enjoyed it. I’ve read about LOP operations many times but never saw it saw clearly. Thanks again.
Thanks, Evan. Happy to hear you found this helpful.
- Martin
Martin, thanks so much for this excellent explanation. I was “raised” on ROP operation, and have been hesitant to change due to perceived risks that I now understand are not entirely accurate. Your work here, as well as further information from the folks at Continental, gives me more confidence to explore this further. Thanks again, and please keep up the good work.
Thank you, William. Glad I could help clear things up a bit.
- Martin
@@martinpauly one question. My Baron has an Insight Gemini 1200 engine monitor. You mention that when going LOP, I should reference the LAST cylinder to reach peak. From what I can tell, this monitor only provides a “blinking bar” indication for the FIRST cylinder to reach peak. Any suggestions?
Amazing and very informative. I remember leaning 172 to the point the engine almost starving,and then quickly turning the mixture two full turns, and now I understand that there was nothing I could do about further leaning because 172 wasn't fuel injection,it has carburator.
Double trouble with the Seminole when I did my twin.
You got it!
Passed this on to my two partners. We fly a Turbo Arrow so there might be some differences but the explanation is so thorough and understandable (finally) that I had to share it. Thanks for posting!
Glad to hear you found this useful, Tom. In a way, a turbo-charged airplane makes things easier, because you can always act is if you were at sea level. So if you want to fly LOP, make sure you are way on the lean side, to stay outside of the red box.
All the engineers out there, including me, approved this video. Great job!
Absolutely outstanding video! I’m new to this business (building an RV-10) and was somewhat confused when I heard discussions on “LOP or ROP?” This clears it up. Thank you!
Thanks, Scott - and good luck for completing your RV-10, it's a great airplane!
- Martin
In short, you can cool with fuel or air, and which costs the most and the harmonious long life of your cylinders. I learned from one of the best, and I flew a Navajo to beyond TBO without loss of one cylinder or any actual damage. But some don't get the idea. Nice job of explaining the topic. Robert
Thank you, Robert.
Thank you, Martin, for this excellent explanation of fuel mixture and running LoP vs RoP. I'm just learning how to fly and appreciate you're ability to explain this subject matter so clearly!
Glad I could help you make sense of it, Alvaro.
Good luck for your flight training!
- Martin
Excellent explanation from every point of view. I realized how wrong I was flying my Bonanza A36 for not understanding the mechanical part of the process
Glad to hear I could help a little, Fernando.
Best regards, Martin
Martin Pauly an interesting topic could be the pre-flight checklist, either the outside of the plane or the inside to understand which are the critical parts to take into account. What I see is that many people (including myself) have no idea what to look at, and what it is for. Thanks again, regards
since flightsim 2020 i learned so much about aviation thanks to people like you who make these really awesome and easy to understand tutorials and lessons. thank you so much!
My pleasure!
- Martin
Martin, I came across your tail wheel training with Doug Rozendaal as I was refreshing that skill. That was great. Then looking further I found your explanation of Lean of Peak operations here. You gave such clear instruction that you have expanded my understanding of the chatter I hear from my EAA friends that have CHT and EGT monitoring in their cockpits. This is new from my general aviation experience. Thanks
Just the B E S T way to explain LOP/ROP operations... !!! EXCELENT!! Thank you...
Thank you very much!
- Martin
Great video Martin. I took the APS seminar 17 years ago when I bought my Baron and have used GAMI's and JPI 760 to fly LOP ever since. My goal was not only economy but trying to be "nice" to my engines to put off the expensive overhauls...
Since then, I have also read John Eckalbar's book, "Flying High Performance Singles and Twins". He has some great analysis (with more math than most would like) about efficiency and range. Your video shows us the result of that with the mpg readout on the jpi. The combination of burning more air and less fuel combined with the slower IAS is a win win for range enhancement. As a real life experiment, I flew my Baron LOP at 13k ft maintaining aprox 140 kts IAS (very slow and extremely patient) all the way from WI to east central FL. Took a little more than 6 hours but had >2 hours of fuel left in the tanks. Could have continued to Key West! Way more than the POH tables from 1970 would have allowed even at best economy.
That said, in the spirit of academic skepticism, the analysis you present about fuel savings to TBO might be unfair because we generally fly to destinations vs. for hours flown. If by flying LOP we take longer to fly there, we use more of our hours toward TBO and cannot claim the gallons per hour savings as real. However, if by flying LOP, we extend our TBO time (on condition), then it holds up fine. My experience has happily been that although I can't prove that 2500 hours at lower CHT is why I was able to do that.
One comment that one of the APS guys made that has stuck in my mind is that if we still want to go fast (Bo's and Baron's like to do that), stay at a sweet altitude 7-9k, bring the rpm's up, sacrifice some fuel economy but stay LOP -keeps the cht's down, and brings the airspeed back up that 8-10 kts that you saw was lost on your flight. Have you tried that?
Keep up the great videos!
David
Thanks for the feedback, David.
You are right in that the fuel savings analysis was very simplified and only looked at one at of many possible angles. Extending the life of the engine is a big factor, but how do you make generally valid assumptions over how many extra hours you get? In order to avoid getting overly subjective, I tried to keep this part of the video plain and simple - even knowing my analysis was not complete.
Best regards,
Martin
Hi Martin,
Awesome explanation, thanks for taking the time. I'm also curious about the fuel savings "at the same HP output" as David implied above. this could be by either taking up the RPM to get back to speed, or by staying ROP and lowering MP to get to the LOP speed. I do fully understand the other benefits to LOP but I'm curious how close the fuel burn would be at the same output ROP.
This question also helps those not running constant speed as they don't have the same level control over all the inputs to get the desired outcome.
Hi Steve,
GAMI has determined that in their engine test stand. Refer to this image:
www.gami.com/img/gamijectors/test_results/tritcm1.gif
Looking at the center and the right portion, there are two power settings for the same engine (with GAMIjectors in both cases) producing the same HP output, 196 HP or 65%. The difference is the center image represents 23" of manifold pressure while 25 degrees ROP, while the right image represents 24" MP while 25 degrees LOP. So the higher MP while LOP offsets the power reduction from running lean of peak, to get back to the same horsepower. The savings here from LOP are one GPH (12.5 vs. 13.5), which is generally accepted as the portion of the savings coming from running LOP, as opposed to savings from flying slower.
Best regards, Martin
Martin, thank you so much for the gracious reply... I realized the answer was in another comment I hadn't read yet. Sorry about that.
Another question is regarding the red box size. Is this literally determined by the range of unacceptable CHT's? I'm asking in regards to any leaning with a turbo (usually at higher than 65% power)?
Steve, that (range of unacceptable CHT's) is not a bad way to think of it. One thing I should point out, unlike what the graphics in the video suggest, the red box doesn't have a sharp, clear boundary - more like shades of pink.
With a turbocharged engine at higher power settings, you will have to be more lean when LOP (and more rich when ROP) compared with low power settings.
The best instruction I’ve seen on this subject. Many thanks for taking the time to do this.
Thank you, Arnie -- glad you liked how this turned out.
- Martin
On my RV7 not only did I run the engine almost exclusively LOP (in cruise) I also ran autofuel. The problem of course with autofuel is potential vapour lock on a low wing airplane. For this reason my IO360 did not have a mechanical fuel pump, it dual redundant electrical fuel pumps instead. Never had any problems over 500 hours and the borescope showed a completely clean engine when I sold it.
Glad to hear, Frank.
- Martin
Thank you. First time that someone is finally explaining this clearly and understandably! Well done.
Thank you, Maarten - glad you found it helpful.
- Martin
Great presentation.........unfortunately most instructors know nothing of these LOP operations.........outstanding video..
Thank you for the kind words.
Mixture management is not really a difficult subject, but one that gets little or no attention during primary training.
Regards, Martin
I imagine this is GREAT info for aircraft owners, not so much for wet renters like me. The explaining was superb
I see your point; as a renter paying a wet hourly rate, you might as well go in fast mode (i.e. ROP). Having said that, if you can stretch your range so as to avoid a fuel stop on a cross country flight, flying LOP may still save you time and money.
- Martin
Martin, really, really good video - thank you for making it. The one issue I see, and it is certainly not a fault with your theory or practice, is that most club aircraft have one single crappy EGT gauge that takes about 5 minutes to react to mixture changes. I on that basis have refrained from leaning out normally aspirated engines, because the feedback on how the engine is feeling in reaction to the mixture leaning just isn't quick enough to give me confidence that I am far enough LOP to be out of red box territory in a timely manner. I did however fly a TIO540 engined aircraft for a short while, and the aircraft was fitted with an EDM800. What a fantastic improvement this was. in VMC at least, it was the best instrument in the cockpit by far. The turbo aircraft do need much more careful management of mixture, and given the near-instantaneous per-cylinder information the EDM gives the pilot, correct mixture control was possible. I say possible, because unless you are an instructor with a few thousand hours on the specific aircraft, leaning mixtures based on the crappy EGT gauge most club/school hacks have in them is risky business, impossible even. I don't know why more flying syndicates don't fit EDMs in their a/c - OK its a couple of thousand dollars I think, but what price engine rebuild? If its a TIO540, about £50k...
Thanks for your comment, Edward. I agree the engine instrumentation of your typical flying club airplane leaves a lot to be desired. And from what I have seen, that probably matches the level of knowledge and understanding of engines management that most pilots have who fly these airplanes. 😁
And to be honest, for beginner pilots and the trainer aircraft they typically fly that's probably OK. There is so much to learn that an in-depth understanding of engine operation is probably too much to ask. But when pilots step up to high-performance aircraft with more powerful engines, that understanding and the instrumentation necessary to apply it become a lot more important. A TIO540 is a lot easier to damage from wrong operation than an O320. A modern digital engine monitor will pay for itself quickly in these airplanes.
Kind regards,
Martin
Unbelievable video. I fly a 1980 A36 (520) and have really been perplexed by running lean of peak the last couple years. Thank you for this! Exactly what was needed!
This is heresy I tell ya! Leaner Always means hotter...so they taught me... Its black magic. Great presentation and loved all your sensors verifying the conditions. This must be how Lindbergh taught the P-38 guys how to significantly increase range and the engines showed no damage from being lean. Thank you, great job.
Thank you. And you are right, LOP is not new, it was the normal way to play back in the day of piston engine airliners. It was how they got the range they needed.
I've never been involved with aviation in any way but my daughter is starting Parks college in the fall to become a commercial pilot, so I'm taking an interest in this stuff to be able to converse with her about her licensing and aviation path. It's interesting to see in the comments how few pilots understand engine theory. I've restored classic Chevys and built high performance Chevy engines for 40 years, and this theory is extremely basic and straight forward, yet seems to be black magic to many. This video should help clarify this theory. Well done.
Thank you. I agree, engines aren't rocket science. In the early days of aviation, when piston airlines traveled across oceans, these piston engines were better understood by many pilots than today, it seems. In fairness to pilots: there is A LOT to learn to earn a pilot certificate, and engines and engine management are only one of many, many topics. I would also say that the average trainer aircraft these days has a rather forgiving and robust engine, and it's hard to damage them through improper operation. But when pilots step up to high-performance piston airplanes, engine management becomes a lot more important, and I hope this video helps them become better prepared to treat their previous engines well.
- Martin
Along with the many praises you've gotten here, I will say excellent job. Mike Busch has also done a very good job of describing the "big pull" I haven't yet watched a John Deakins presentation.
I have had a JPI gauge for several years and now have a Garmin GI275. They say you need to lean slowly to watch the temperature rise come to a peak. This puts one in danger of dwelling in the Red Box for too long, and doesn't seem like good advice, but it's what you get when you buy the gauge. I'm glad you and Mike have provided clarification.
I like your suggestion of determining peak EGT from the lean side after doing the big pull. Other advice has just said do the big pull and then settle on a desired fuel flow or EGT?? I don't know which, but I like the idea of knowing where peak sits and then being able to lean from that a desired amount of degrees. Now I have to go out and practice and find my last cylinder to peak.
I mostly operate at 65% power so shouldn't have to worry about the red box, but sometimes want to operate at higher power. By the way, with the GI275 I have a power readout and that is an option in gauges from JPI and EI, so it's becoming much more common now to have a direct percent power readout. I do wonder hwo accurate it is?
Thanks for the video. I’m getting back into flying after 22 years. Your videos help.
Glad to hear - and all the best for getting back in the saddle!
Regards, Martin
Martin, I watched this video before but now it has proven more beneficial now that I just got a new Dynon HDX with the engine monitors. Thanks for sharing!
Glad it helped!
- Martin
@@martinpauly If you are ever in the Denver area, please look me up!
wow this is awesome! very very well made. it couldn't be more true that being able to teach someone about a certain topic means you have really mastered whatever that topic is.
Thank you, Jeff.
- Martin
Excellent video Martin ! "Baron Pilot" recommended this and he was right. I spent many years in a 58 Baron, with performance conversions on the engines. I understand the mixture, temp and power settings much better now, than then. Especially the "why" questions. You did a great job in simplifying this. Thank you for sharing this valuable information. Safe skies !
Thank you for the nice feedback, Randy. I'm glad you followed the link from Baron Pilot's and Lucy's latest video.
This helped me allot. Two new overhauls coming for my PA-30 this month. I added an EDM 760 and LOP has been recommended. Very nice resource for me to keep coming back to. Thank you!
You are welcome, Frank.
Enjoy the new engines on your Twin Comanche!
- Martin
I also have a PA30 with a EDM760! Haven’t tried flying lean of peak much yet, have just been following the POH power tables for flying at either peak or 50-100° rich depending on power.
What kind of CHT temps are you seeing during LOP operation? Do you find the fuel economy to improve from the best economy (peak) recommendations in the POH?
Alex1911 I’ve only tested it thus far. Next flight will implement it. Expecting 7-7.5 gph. Smooth operation all the way down to 5.7, getting cooler as you lean. I’ll report longer runs with more valid ops data. I’m curious about the TAS
Frank Dorrin yeah that’s what I’m interested in since the POH says best economy is at peak. But I’m guessing they didn’t test LOP operations since the plane wasn’t originally equipped with an engine monitor. Let me know what you find in your experimentation! I’ll do some testing on Monday if the weather is good.
I also take everything in the ICS POH with a grain of salt since it’s full of errors. Like the starting procedure which leaves the fuel pump on as if it were an O-320 vs an IO-320, not mentioning feather in the engine fire procedures, leaving the mixture cut off and fuel shut off in intentional single engine ops, and their backwards engine failure procedures that call for drag before power.
Lovely job, Martin! I operate my Lancair 360 LOP (lucky to be able to do it since it's not injected). The biggest challenge is to not fixate on ONE cylinder, but to identify which cylinder is last to come to the LOP party. In other words, it's quite possible to have 3 cylinders 25LOP while the last remaining cylinder is still ROP. This manifests itself with high CHTs on the last cylinder. I keep leaning until ALL the EGTs are coming down. Basically, once I see one EGT drop, I ignore that cylinder and keep watching the others. Eventually there's only one left, and that is what I use to gauge where I am on the curve from that point forward. Of course, by the time IT starts playing ball, the other 3 cylinders are further along the lean side, producing less power, and you can end up with some vibration. It's a tough balancing act, and is the reason that most carb engines can't run lean of peak. Balanced injectors make things a LOT easier once they're setup correctly, but thankfully, I've made it work with my Lancairs. ROP the CHT's will be 420+ for me. LOP they're around 350-360. TAS goes from 197KTAS ROP to around 190KTAS LOP with approx 20% fuel savings, just as you demonstrated.
Thanks for the feedback and comment, coma13794. Your description of your leaning process is spot on, and I am happy to hear LOP works as well as it does with your carbureted engine. Nice!