Great stuff. I just want to make 2 suggestions: 1) Add a full rich run-up before your lean run-up. This tests the fuel system (pumps, carburetor/injectors) at max flow/duty-cycle. Your lean run-up should take care of any spark-plug fouling worries. 2) Even for PowerPoint, 240p is too lean of an upload resolution.
I cannot lie, I was afraid of leaning the mixture in my Arrow due to only having an EGT gauge. The POH also recommends that the mixture be left full rich below 5000 feet, which I’m seldom above unless I’m traveling. I’m glad I found this video, it goes against everything I was taught and almost everything the POH says - but I want what’s best for my engine
Sir, thank you for making such a comprehensive tutorial available to the general public. You have a wonderful teaching style that makes this data-heavy area (relatively) easy to understand.
Maybe if the guy actually started talking about leaning aircraft's engine vs 7 minutes to tell us Embrey Riddle didn't do things right. This is an instructional video not story time.
@@foxtrot789 I haven't seen such a high horse in a long time. Why don't you try getting off of it and just be thankful Mike is kind enough to share this knowledge with us, free of charge?!!
The best information I’ve got on adjusting mixtures. Everybody is afraid to run lean of peak where I am at. Mike getting 200% TBO tells me he knows what he’s talking about Just getting ready to break in my newly rebuilt I/o 470 I’m going to do everything I can to follow all the advice to the letter
I just stumbled upon these Savvy Aviation videos and am really enjoying them as a no longer current but always a pilot kind of a guy. Mike’s approach to redlines is spot on. Reminds me of comments of a Mississippi River towboat captain who said of the red and green buoys marking the river channel: Those buoys don’t mark the end of safety. They mark the start of danger. Stay the hell away!!
Great presentation and advice. One small correction: at 30:46 Bush says airspeed varies with the square root of power. Airspeed actually varies with the cube root of power, so 3% more power is only 1% faster, and 10% less power is only 3.5% slower. For an intuitive explanation why, consider an airplane flying a distance D. Drag varies with the square of speed, so at twice the airspeed, there is 4 times as much drag. To go twice the speed, the airplane engine must make 4x the thrust. That means it does 4x the work over distance D. But at twice the speed, it's covering that distance in half the time. 4x the work in 1/2 the time is 8x the power. That is: power varies with the cube of airspeed.
No, the speaker is correct. Power offsets drag in level flight, and form drag goes up quadratically with airspeed. The discussion there was the relation of power to airspeed. You are discussing the relation of power over distance, which is the integral of airspeed - hence the discrepancy in the carrying the quadratic into a multiple.
@@chronikentertainment7856 Thrust (not power) offsets drag, and power is thrust * speed. So thrust goes up with the square of airspeed, as does drag. But power goes up with the cube of airspeed. Simple example: consider an airplane that wants to fly twice as fast. Drag is 4 times higher, so the engine must produce 4 times the thrust. That is 4 times the work, over any given distance. But it covers that distance in half the time. Doing 4 times the work in half the time is 8 times the power. So doubling the speed requires 4 times the thrust and 8 times the power. Thrust increases with the square of speed, power increases with the cube of speed.
Thanks Mike. To date this has been the most informative lesson I've seen reference leaning. I've searched POH's, online sites and engine maintenance instructions and manuals. Really great stuff! Thanks.
@@savvyaviation Mike. I’ve flown by your words for decades. Love your books . Now. Loving Ask The Mechanics! One area where I am a little puzzled: 1. Stay out of the Red Fin (or box). 👍 2. Avoid high CHTs. 👍 Gotcha So, I can be right at peak EGT but the CHTs stay happy at 380 or less with cowell flaps open. Is it really ok to be at peak EGT as long as the CHTs stay cool?? Cessna 185F IO520 typically: 24hg/2400 RPM. Thanks 🙏
Amazing video. So much good knowledge on proper engine operation. I like many were trained in the super rich mindset on rentals but now as an owner of an ‘86 Mooney M20J with GAMI injectors, this has changed the way I operate. Luckily I am able to keep below 380c even in the climb and LOP at altitude the CHTs are in the low 300’s. Running great so far at around 150 ktas and around 8.5 gph.
Hey Mike - fantastic videos. On this one though: wouldn't you want to go full rich for landing...since it might be a go-round (takeoff equivalent)? Obviously adjusted for high density altitude cases...
I would love to run LOP butI have a normally aspirated PPonk 275hp engine in my 182. I also have an EDM830 gauge that show all the temps on each cylinder. Well the differential is 100deg or so on EGTs and 25deg on CHTs. I have tried the carb heat trick but still get 80 deg differential. If I lean so all the cylinders are happily cool the engine runs rough.
Great information, and a very understandable presentation style. I looked up Lycoming Service Instruction 1497A and it specifically addresses IO-360-L2A engines. I know you discuss how to lean for carburated engines, but has Lycoming ever released any service instructions or other documentation that addresses more current leaning procedures on other engines? In other words, is there Lycoming documentation to support these techniques on my 0-320-E2D?
I know it’s been a while since you all have asked your question, but Lycoming Service instruction 1094D covers leaning procedures for all Lycoming opposed series engines.
question about taking off in a simple plane. your basic checklist from 15:13 says lean in a climb above 3,000'. But before that you said full rich should only only be used for a maximum of a minute or two. Well, it will take a lot more than 2 minutes to climb to 3,000' from a sea level airport in a 172. Whatre your thoughts on that?
This is great videos! However I can only see it in 240 resulotion which makes the diagrams hard to read. Any chance they can be put out on the tube again witv 1080 resulotion 🙏🙏
The last time I flew a piston was like 30 years ago. My plane didn't have egt and cht guages and I'd lean only when I'd reach cruising alt by pulling back on the mixture till the engine runs rough then push it back a bit. Wondering if this is what LOP is. anyone? Thanks!
I’ve got a 1975 172M with a 180hp O360A4M. It does have a simple EGT but nothing else. I’m a little confused on what he means by engine complaining. While leaning I notice an rpm drop but still smooth operation during the leaning process. If I continue, I get noticeable roughness. Is the start of the RPM drop the complaint or is it the actual rough running?
1:04:15: 30" manifold pressure EGT is lower than 25" manifold pressure EGT because 30" is more efficient, more work gets done, more of the available chemical energy is consumed creating useful work resulting in lower waste energy thus lower EGT because EGT is a measure of waste energy as you said.
One small but very important correction: dropping a lit match into a bucket of fuel and having the match go out only works with Diesel or similar (low volatility, no vapor cloud forms.) If you try that with a bucket of gasoline as suggested in this video, you will get a very dramatic fireball (and maybe 3rd degree burns), as gasoline is a volatile fuel and it will form a vapor cloud. The match will ignite the vapor cloud, which may be big enough that it envelopes you, resulting in a big flareup, and igniting the liquid gas in the bucket. Other than that, good video.
No, this is not necessarily correct, sorry. The speaker is indeed right - take it from me as a once stupidly adventurous teenager. (please don't try this unless under controlled conditions). At higher temperatures where vapour clouds form, yes, a fuel surface may ignite. But at average room temperature a "bucket" of avgas will not ignite. Also, liquids in themselves will not burn (there is no molecular contact to sufficient oxygen) - once the vapour above a fuel surface has ignited, it will heat the surface to release more vapour, thus sustaining the fire. It's the same reason we need choke or prime to start our engines when cold - the fuel has condensed on the cylinder walls, so does not want to ignite as a liquid. We need to prime the system to force a higher fuel vapour / air mixture within the cylinder for the first ignition. After that, temperatures increase and fuel no longer condenses to the cylinder wall.
When I was a student pilot; it made me nervous messing with red knob in flight as it was a mental "kill engine" knob. Lol was afraid I would mess up and kill engine. 😁 My instructors never spent much time on leaning.
I think this is a common problem with flight instruction, especially at low altitude schools. Partly to simplify early lessons I'm sure. They would also rather clean fouled plugs than to replace holed pistons caused by incorrect leaning of noobs.
On descent, i notice you can go really lean without causing roughness to the engine (due to very little power being required since you're going "downhill"). Is that ok? I assume the biggest risk is not remembering to enrichen when you get into the pattern/final. Just seems like a no-brainer way to save more gas. Mr Busch, I'd love your thoughts on this. I fly a 180HP Lycoming o-360 in a 1965 Mooney M20C.
In the very beginning, it says lean to roughness then enrich. So if no CHT gauge, isnt possible to be in the red box? My Cherokee 6-260 doesnt have CHT. So if I lean to roughness, then enrich till 70-100 degrees ROP, isnt this what I was taught 30 years ago? So many questions..
There's no CHT gauge in the planes I fly also, and it's not easy to operate LOP on them without engine roughness. So the goal (in my mind) is to operate at a power level which is low enough that I'm not in danger of running in the red box. Just refer to your POH for power charts. If you run under 70% power it should be pretty much impossible to be in the red box. In any case, I think, at 70% power, stoichiometric (or slightly LOP) is better than 70-100 ROP, as you will save a lot of fuel, run cleaner, and sacrifice very little airspeed.
Most people have gotten the message about leaning while taxiing, if for no other reason than it prevents having to do the plug cleaning shuffle during runup. I'm always leery of leaning while climbing or anything involving full power. I can totally understand leaning when the DA is high but again, how much is safe vs what will hurt the engine.
Thanks Mike, great instructional video. Really pulls it all together in an easy to take in, digestible and comprehensive package. I learned a lot from this, very quickly. Is there anywhere we can get a nice clear printable copy of all the charts you use to explain it?
Love to hear your thoughts on an engine like a Rotax 915is. I fly a Sling Tsi and I have full FADEC. I can run Full Throttle forever, but that sucks gas. So I usually back of until it goes LOP, and have a choice of 5400 RPM at about 8.4 GPH or 5000 RPM at 7.3 GPH. I get about 18 mpg at the higher power and 21 mpg at the slower setting. Max FF is about 11 GPH. This video was very helpful in understanding the operating regions. I have an advantage with fluid cooled heads, so CHT is a non-issue (I think). Thanks for the detailed info.
As always, great explanation! I am reading your books and I am convinced you are one of the best experts out there. BTW: I own a Landrover Series II, built 1960. I know how to handle a choke :)
I was taught on o320 to lean to stumble and then 6 half turns in. Never really knew why and didn't notice much difference from say 2-3 turns in. So I've been running too rich I guess but not by much. I have leaned again at say ~10,000' after sea level departure and never only noticed say a 1-2 turn difference.
@@brentdavidson1maybe but most a&ps have no concept of the real world of flying. They are simply not taught anything close to a detailed explanation like Mike teaches. Totally depends on their background. If they are farm boys or grew up working on engines this is very basic and easy to understand. If they are city boys that never changed oil before a&p school, not so much. A&P license is just a certificate to learn sadly. I was shocked when I went through school. They prepare people more for the airlines than GA. Also, if you study Mike's material, the safe and easy way to truly get much more than tbo out of your engine, you need to have an engine monitor. Takes all the guesswork out of the equation. His advice is always about stock engines too. Even more important to have a monitor on modified engines.
Most people were trained on four cylinder engines with carburettors which are notorious for having unequal pressures in the cylinders. No seperate EGT and CHT temps per cylinder so very difficult to lean adequately.
I fly the Cessna 152, with the O-235 which also have a cht gauge installed. I find that at even the 50 degrees rich of peak (which is the the recommended POH leaning technique) the cht does not get above 340 even at 75% power. Is this just because it is lower power and only four cylinders? I don’t see an issue of leaning rich of peak because of this. Does anyone else use a different leaning technique for engines like the o-235?
But why would you want to run the engine at that mixture setting if it's neither best power neither best economy setting? To get something in between? But you're getting this compromise where it's most stressful to the engine. I would choose what I want (speed or economy) and set the mixture accordingly.
Most modern engines(like post ww2) automatically adjust ignition timing based on at least RPM or throttle position often both. The 20degrees the mechanic sets is the reference point at idle, if you keep the timing light on and rev the engine you can see the timing shift 10 or 15 degrees. I don't know if this applies to an L-320 L-360 type engine.
@@brettdavies-young7102 I suppose that is reasonable considering they operate most of the time in a moderately narrow RPM and load range and fixed anything is more reliable than adjustable. The trade off is reduced efficiency from idle to low-cruise manifold pressures[high altitude] with retarded timing, or reduced max takeoff power without knocking with more advanced timing.
@@mytech6779 What is even MORE "reasonable" is not adding a mechanical variable timing feature that would introduce another possible failure mode. That's not to say that I for one would turn my nose up at a _cockpit adjustable_ timing control, but most pilots probably wouldn't make the effort to master it's use.
@@craigwall9536 The rotax 915 burns 7 gph in cruise and is turbanormalized. One lever FADEC control for engine and constant speed prop, mixture auto runs lean of peak below 80% power. They have computer controlled direct injection and spark ignition controls.
Only holidayed for a few days in Florida from the UK. But the humidity there must produce very rich mixtures as Embry experienced. No wonder the engines were rough. Also if you have problems starting, usually pilots start over priming, get the mag switch checked out. Seen quite a few where cranking position was earthing both mags, no wonder the engine wouldn't start until the key was backed off slightly. If in doubt, just remove both mag wires of the key switch and see if it starts any easier.
What is LOP? Is that mean low oil pressure? On the subject of leaning, I noticed some engines like the ones in a Beachcraft bonanza allows you to run lean of peak. The. Warrior I fly states to run the engine wide open and adjust your RPM with leaning to provide cruise RPM. I noticed in the Cessna 172R POH says extensive running, lean of peak is prohibited, and that statement is done in bold face. It’s all confusing of who is correct and who is not.
Do you have a discussion about leaning engine (IO540-AB1a5) or similar with only basic single cylinder CHT gauge and basic EGT. Lycoming says its fine to operate at max EGT below 75%, but people tell me its not safe because I don't have a sensor on each cylinder. Lycoming also has recommendation for leaning without CHT or EGT by just leaning to leanest setting that results in smooth operation. What are your thoughts on that method?
Mike - when talking about turbocharged engines you say, "Controls full forward except the 182T... manual wastegate/etc." I fly a Pa-44-180T that has a manual wastegate as well. So, throttle to desired MP rather than full forward? (Great videos and great service to the community!)
Only problem with not doing full rich on landing is that if you're part of a club or school, the CFI is either going to force full rich because of their own primacy, or the school/club otherwise prohibits that method of landing for checkouts, proficiency checks, and refreshing. So unless you do this solo in the pattern for practice you probably won't get to wriggle out of full rich mode reflex. You own your own plane, probably not so much a problem. The CFI will "unlearn" the practice when you're with them, and you'll have to "re-learn" landing leaner solo. Also, I suggest turning off comments if you record a cockpit view and the peanut gallery sees the leaned mixture during landing.
Your PoH recommends that because they can't be sure you've got even mixture distribution and they don't want you to have one hot cylinder and not know it because the CHT probe is on the wrong cylinder. IOW's it's a "product liability" issue- read that as "lawyers" and "nanny state". The cure is to have at least CHT on every cylinder and run with the throttle wide open and significantly LOP.
I run mine at 570 degrees all day... My engines only last 400 hours before they need to be rebuilt and 2 of them have had catastrophic failure. You think this is why?
Wow! A lot of very useful information in all your presentations. Since there wasn't much time to address questions... When you look at the EGT gauge for the leaning, do you do it with the hottest cylinder, coldest, first to peak, last to peak, or doesn't matter? I'm guessing that not all cylinders will be peaking at the same mixture setting.
I am a little confused. I typically fly airplanes with just oil temp guage if I am lucky I have a functional egt. I Typically lean to roughness than richen till engine runs smooth. Would this likely be rich or lean of peak ? Is lean of peak beyond that initial engine roughness?
Another one of Mike’s videos regarding CHT’s he states that running a lycoming in normal cruise up to 420f is okay. I’m not sure why he is so hard over on the 380F in this video. Hopefully he can comment and rectify the discrepancy. Generally I find his videos extremely educational.
Great presentation, I’m a first time airplane owner and I’ve been slowly digesting all your webinars, books, articles. I do have one question, you mention leaning for max RPM, how does one do that without these charts? My aircraft (C120 w/O290) only has a single EGT/CHT gauge. I’d like to get an analyzer at some point, but for now what’s the best method? Thanks for the great content.
You stated that full rich should only be during startup and takeoff below density altitude 3000 and only briefly. What if you're doing closed traffic work in a pattern that has a density altitude below 3000? You'll definitely be there longer than a few minutes rich. Are you leaning on downwind and then enriching moments later per poh (C-172)? I agree it's best to lean when you're cruising and have altitude but in the pattern that slight engine roughness during leaning seems like you'd be asking for trouble. Curious on this because I've cleared fouling on runup only to have a problem on my 5th takeoff roll (closed traffic work). Admittedly I may not have done the foul clearing as long as I should have but still curious for an answer to my questions above....thanks in advance...
That's a very interesting point. Maybe it's a good idea to leave the traffic pattern for some time to "clean the plugs" after a few touch and gos. Personally, I would avoid this extra workload of setting the mixture for each pattern. At some point something will go wrong... right?
@@LeantoPeak Yes, leaving the pattern would have been better. My problem at the time was my radio stack was legacy 1978 172N with 1 mk-e replacing an RT-385. Leagacy transponder and tailbeacon was the only thing working.. I was reduced to handheld. I couldn't leave traffic pattern with that setup. I decided to fly plane in pattern just to keep oil circulating and tires from dry rotting in the hanger. I've been doing that for the past several months. In the interim I've discovered that getting oil up to temp at 1000rpm and leaning to peak rpm works. I asked my A&P if that is ok. He said lycomings preferred run-up procedure is different than the POH and close to what I was doing. Do you know anything about that? Btw...New stack delivered just waiting on install.
@@muhammadsteinberg gotcha. Enjoy the new stack! I wouldn't know, I'm just a noob pilot flying rentals, but what you mention makes a lot of sense to me and sounds healthier to the engine compared to traffic patterns. Or maybe you could remain in the pattern but maintain altitude (like simulating a go-around or simulating the runway was occupied). The only difference of running it up on the ground would be cooling, but if power is not excessive it should be fine. Hard to say for sure without CHT gauges though... cheers happy flying!!!
What happens if I don't get any engine roughness even when leaning aggressively? I'm going full throttle and then setting the mixture to get the power setting I want. Does that make sense? Cheers.
As Mike said, use rpm peaks or lean to acceptable roughness. I've found that adding carb heat in cruise helps smooth out many Cherokee engines. Works for the 320' 360, and also 540 in my Pawnee.
Some models of Lycomings have _rotten_ mixture distribution (it depends on the intake manifold and the position or angle of the throttle plate). If nothing else, get 6 CHT thermocouples and one gauge and a rotary switch so you can look at them all. And then actually pay attention to it!
I've heard it's neigh impossible to properly go Lean of Peak with a carbureted engine. Is that true? How much harder is it to properly go LOP carb vs injected?
In the planes I fly it's quite hard indeed. I feel as soon as EGT has peaked, if I try to go leaner immediately it runs rough. Maybe it means it didn't even reach stoichiometric and it's already running rough.
@@mytech6779 Not to mention weight and the now improper loads on the motor mount vibration isolators because of the added weight out at the very front of the engine.
Mike, I didn't understand one thing that's maybe answered in the subsequent classes. Are you ONLY using CHT's to lean, or are you starting with peak EGT (such as using a "lean find function" on the engine monitor) and then leaning from there using CHTs and fuel flow? Thanks for the great class!
Never mind Mike...watched your advanced class and read a couple of your articles and you definitely answer that thoroughly. Thanks for the great information you put out there.
20yr firefighter and safety guy here… The gasoline bucket thing is something you shouldn’t try lol. This would be true for kerosene… not for gasoline. Flashpoint is drastically different between those.
Going farther is a lot better if you’re an aircraft owner. If you’re an aircraft renter and you’re paying on the Hobbs meter then I would think you would want to go faster.
Pretty sure you’re also supposed to be full rich when operating over 75% power on most piston engines. That example around the 50 min mark should be full rich if it’s being used I would think. Then again I’ve mostly flown Lycomings so maybe Continental is different.
Dumb question...but I just don't get why they can't make airplanes lean like a modern car. Is it because a plane can gain elevation faster than a car on the steepest road? So... we don't make computers fast enough to handle this? I have 30 years programming computers and just learning to fly. These are the questions that my CFI hates.
The electronic solutions in your car don't have to be certified by the FAA. Probably much easier and cost effective to have the simple tried and true mechanical equipment certified.
Im not Saavy or a mechanic but ill try. In the run up you are running at a 1700-2000 rpm which should put most airplanes well below the "red box" + it helps get the engine warmer. Also, the hottest point is typically about 50 degrees rich (egt) of peak. Best power is 75-100 rich of peak egt. I believe what he is saying is that the engine is better off leaning the mixture tell just before its running rough than running 50 degrees rich of peak egt (which is what most engine monitors aim at).
@@BonanzaPilot Your analysis seems to be consistent with the chart at the 29:25 time mark. Best power on the chart is slightly rich of peak mixture. Even peak mixture is slightly rich of stoichiometric mixture, but best power is slight rich of that.
I watch this, especially the part about the timing of compression, ignition, expansion, crank angles, etc. and the coordination with the other cylinders, and I think, 25-50 years from now, people will look back and say, "OMG, those old IC plane engines were such a complicated mess, teetering on the edge of failure… our electric motors are so much simpler, lighter, more efficient, with fewer components, and easy to manage and maintain!!"
Every summer, the school's planes will hardly idle due to the fouling, drives me nuts. Takes 3 minutes of extra lean runup time just to clear it up. They all just point to the 40 year old manuals and claim legal liability. I shake my head.
Just remembered they had a plane that was running very hot, oil temperature, in cruise. And I was like "hey I want to try leaning it I have a hunch that might be the problem", but the instructor was all "no richness makes it run cooler and we are only at 2000 feet". To this day I think the issue was either extreme excess fuel washing the oil off the cylinders and causing less lubricity, or that the throttle was set too high for the airspeed to make up for the reduced power due to incorrect mixture.
15:03 The minimal leaning checklist There's one situation you didn't talk about (although you got close to it later), and that's the high-altitude go-around. How would you lean for this? You don't have the luxury of being able to lean for maximum RPM while you're descending and entering the pattern, so what do you do? All you know for certain is you don't want to go full rich. Could you, say, lean for pattern altitude (whatever that entails), then go half a turn, or a full turn, richer, or maybe just leave it set for pattern altitude?
During a high-altitude go-around with a normally-aspirated engine, the engine is only putting out cruise power (75% or less), so leaning is no different than what you'd do in cruise. If the engine is turbocharged, it "thinks" it's at sea level, so you'd go full-rich just as you would at takeoff. Hope this helps. -Mike
i was too afraid of leaning 😂once i was flying with old and bold instructor he saw me doing it very slowly and he pulled it all the way up and pushed it back .. since propeller was windmilling nothing actually happens u get back the engine . To stop windmilling ur speed should be somewhere near your stol speed in fixed pitch prop
What a boat load of information. I believe most general aviation pilots are oblivious to any of this detailed information. I once a stearman and the POH was even counter to Continental's start up procedure. I think all of this misinformation centered around the US Army Air Corps need to put pilots in aircraft before they grew long grey beards and fathered a dozen off spring. This level of mechanics back then was unheard of. We needed pilots converted from farm boys, not from physicists.
If your engine oil gets black quickly , after an oil change , you are running it too rich.........carbon goes out the exhaust as dark unburnt fuel and the piston rings are scraping carbon off the cylinder walls and loading up the lube oil with carbon.........diesel lube oil gets black quick for this reason because the carbon from combustion passes the piston rings and fills the oil up with carbon..
Oxygen sensors in the exhaust and positive mixture control as per all automobiles now would be the answer not having 1930s tractor carbs and constant spray fuel injection wasting fuel and demanding constant attention from pilots that do not know how to do it anyway.
Mike might be slightly misinformed about the constant LOP condition of modern cars. The system there only cares about the maximum life of the catalytic converter doing the emissions clean up of the exhaust gases. The mixture is constantly varied lean and then rich again to charge the converter with oxygen and then to consume that stored oxygen. Mileage takes a distant back seat to emissions at all cost and always. If the converter fails to show expected results of this constant flushing of rich and then lean mixtures, it sets a check engine light code for failed catalytic converter and in some states you can not then get your registration for the vehicle renewed again until the check engine light problem has been fixed. Further, under full throttle acceleration, the emissions rule book is thrown out the window and no use is made of the O2 sensors, the computer wings it with a set of known engine parameters as long as that foot feed is mashed to the floor. You'll need a vastly differently programmed system for airframe work to the one found in a modern car.
Your interpretation of the ragged curve at the ICP peak is mistaken- the "instability" you think you see there is NOT _primarily_ caused by "shock waves bouncing around", rather it is the result of piston ring sealing beginning to fail and the onset of "ring flutter" due to excessive ICP. This is most noticeable in the 30" versus 25" m.p. plot, where at 30" m.p. the rings have simply been overcome by pressure and there is a sudden pressure reduction due to leakage. If you happened to be monitoring cylinder blow-by coming out of the crankcase, you would have seen a jump in the volume at that setting. (It is not the "measured" pressure alone doing this; the detonation actually would push the pressure spike MUCH higher if the rings hadn't vented, so yes, the detonation or pre-ignition is causative in large part. But the raggedness in the pressure trace is due to the rings venting/sealing/venting/sealing as they go unstable in their grooves and lands.) How do I know this? I did an internal research project at Southwest Research Institute investigating this very phenomenon. Aside from the excessive heating, this ALSO blows the oil film out of the ring grooves and off the cylinder walls and leads to a large increase in cylinder wear rate. It also _breaks piston rings_ . Your interpretation of why the EGT goes *down* at the higher manifold pressure when pre-ignition or detonation is present is also _mistaken_ : it goes down because NOW some of the exhaust is blow-by going out through the crankcase breather and bypassing the EGT probe.
Very interesting, Craig. Please: what would your technique be for leaning a Continental IO-470C (at cruise) for most efficient operation (without an engine analyzer)? Thank you!
@@johnrltr Without _knowing_ at least the CHTs for EVERY cylinder, you're basically in a fist-fight with a poltergeist. Having EGTs for every cylinder is even better, but not strictly necessary. Maximum engine economy is at roughly 50 degrees lean of peak, but in fact "most efficient operation" is a little vague- for me, two things are important: like Mike says, lean to roughness _GIVEN KNOWN CYLINDER TEMPS_ (which can be known by a temporarily installed set of CHT probes) AND by having the throttle WIDE OPEN so you know that the throttle plate isn't messing up the mixture distribution and you've got minimum pumping losses. At that point, you can choose your level of roughness: if you've got a tailwind, leaning past "max engine economy mixture" is even better. If you're going upwind, that max econ mixture is the best choice. Now I'm giving you MY logic, but it's ALSO based on flying at the Carsten Speed (or Norris Point), which is the speed that is faster than max range speed; it's the max _speed/drag_ - 1.316 times max L/D IAS at ANY altitude- you've got a 21% speed increase for a 15% drag increase. Faster is less efficient; you ask about max engine efficiency but I'M giving you the conditions to optimize the engine _and_ the aerodynamics _simultaneously._ After that, every foot of altitude is giving you a TAS bump, and so going high and getting the fuel burn down where you can go non-stop is MY definition of "efficiency". And that may be significantly LEANER than "max fuel economy", since THAT refers only to ENGINE operation.
@@johnrltr I have no opinion at all on any brand or model of "analyzer"; my approach is to use a system that can be used on any aircraft with _no electrical system at all:_ I have four dual temp gauges- 2 are dual CHTs and 2 are dual EGTs, arranged so that each stack of 2 dual gauges have the needles pointing at each other, with the top two needles reporting the front two cylinders and bottom two the rear cylinders. (It's a cluster of four 2 1/8th" instruments.) This gives a visual layout that mimics the layout of the jugs in my C-85. A stack for the EGT and stack for the CHT...and all of it run straight from the thermocouples to the D'Arsonval meter movements. No other connections. You could do this in ANY aircraft. Let me tell you: it's VERY comforting to just glance over and see all those needles behaving themselves, everything leveled out and pointing straight across to each other. These are simple Westach gauges right out of the Wicks catalog. The Analyzers are wonderful because you can program them to alert you, select a particular cylinder to act as reference, etc.. But they cost 2 or 3 times what my setup did (actually less because I found second hand gauges and confirmed their operation myself) and they require an electrical system. I don't need the alert feature anyway because I glance over during my panel scans and as long as the needles are behaving and the CHT is below 400, we're good. You can do the same thing with single gauges and 4-position switches, but then you have to work at it. And most people will find the hottest cylinder and leave the switch there, but if something changed in a different cylinder you wouldn't know it. But it's worth repeating: EGT for all practical purposes means basically nothing- all that matters is CHT. EGT is useful if you need to know where peak mixture is, but if you simply lean aggressively to get past peak and richen from the LOP side, that's all you need and you can do that by ear /feel. Watch Mike's video on advanced leaning concepts and the Red Box concept. Finally...and you probably don't want to hear this... once you _know_ that the cylinders are running evenly, you don't need ANY temp gauges if you lean aggressively. You do, however, lose the monitoring function so that only works if nothing changes. I prefer to have them because sometimes baffling leaks open up or birds build nests back where you cant see them. (I've even swallowed toilet paper during a "cutting session" and the temp rises are immediate...) Edit: One other thing: If you do get an Analyzer, try to get one that automatically adds the "cold junction" correction. With my gauges I have to mentally add the cold junction temp to the indication to get the actual temp. That's only necessary for the CHT readings, but if the gauge says 350F and the cold junction is at 50F, the cylinder temp is 400F. I think most digital Analyzers perform that correction for you, but probably not all and you really need to know whether it does or not. With the EGT you don't care what the actual temp is; you just need to detect the peak and know which side you're on. Remember: everything gets better at W.O.T. That's going to be the condition with the least pumping losses AND the best mixture distribution..._usually._ Lycomings are sometimes lopsided no matter what you do. And if it's an injected engine, you may have to do some injector-matching to get things right. Above all else, do NOT tolerate leaking baffles!
A lot of people say that Mike Busch's stuff is bullsh!t and he wrote a book to make $$. My CFI says, that one should go 50* Fahrenheit ROP and keep an eye on the CHT temps, especially if it's a normally aspirated carburetor airplane and you just can't precisely apply LOP principle without an engine monitor. Also, your trip at the end of the day will cost higher compared to your fuel savings, because you're wasting your time between overhaul of the engine plus other parts that have limited resources, as well as your personal time (considering that people buy personal airplanes to go places faster). What do you say?___ I left a 'thumbs up' under the video.
Shouldn't throttle be adjusted to obtain equal airspeed to properly compare lean vs rich fuel flow? A 5% reduction in speed is about a 14% reduction in power needed, based on simple parasitic drag. (probably more like -10% once figuring in the increase in induced drag but of course induced is highly dependent on loading and wing design) The point is that you can't change speed and attribute the change in fuel flow to leaning, that is just bad science and engineering. To be sure the plane I fly is not designed to cruise at WOT at the altitudes common in my area.
So the plane was not designed to fly at the altitudes common in your area. Just kidding. Some people will argue that it makes more sense to leave throttle wide open, and adjust mixture to get the power (RPM) you want. So basically, let the engine get as much air as it can, just control how much fuel you're pouring into it. Makes sense to me, as long as it's not running too rough. Otherwise, I would agree with you.
@@LeantoPeak Yeah I worded it a bit odd. Basically all the VFR here is trapped at about 3000msl under a class B shelf unless we climb high enough to get over 8-9000ft to get above the mountains boxing in the area. Unlimited air and adjusting fuel to get power is how turbines operate and to a certain degree the Diesel cycle, but I was limiting my comments to Otto cycle engines. Just attempting to keep the results as apples to apples as practical. (Both gas turbines and Diesels naturally operate on the extreme lean side.)
@@mytech6779 yeah was just kidding. I think you could have a look at this webinar from Mike, he talks about some nice numbers like knot/gallon and such - th-cam.com/video/ZBr6kjvfzio/w-d-xo.html
When you ask the EGT question there is an assumption on the listeners part that you haven't changed anything else (such as ignition timing). So your question and provided answer are disingenuous.
!) The like button doesn't work. 2) I get over 1,100 miles out of a Cesna 182T by using this technique. ...albeit in FS2020! ;) Slow climb (500 FPM) to 15k lean of peak then cruise to near destination for a free ride back down. AoA between 1 and 0 is pretty good. Monitoring and adjusting EGT pretty much the whole way up. in the sim, the 182T is happy as a clam up to 20K. 22K is a bit too far. Real life? Sorry, I haven't a clue! LoL
@@daffidavit No, no- LEAVE it on, because that richens the mixture. As for "scary engine roughness", if the temps are even, the engine is happy even if you aren't. Rick wasn't kidding- I actually now control power in cruise with carb heat because it's the most convenient way to adjust mixture in cruise. Just "lean to acceptable roughness" and then smooth it out a little with carb heat if you want a bit of climb. I run with the throttle WIDE OPEN and control power with mixture- but don't even think about doing it that way UNLESS YOU'VE GOT TEMP PROBES ON EVERY CYLINDER. And BTW- you can get used to a bit of roughness once you figure out that every cylinder is experiencing the SAME degree of roughness, your CHTs are down below 400, and your fuel burn is WAY down. Notice that Rick said ADD carb heat, not PULL carb heat- meaning just add only what is needed to lower the air mass flow to richen slightly; you're not trying to clear ice.
@@craigwall9536 As told to me once by a manufacturing rep. of Continental engines, "there are only two positions for carb heat, on and off". Use of the carb heater for any other purpose other than to prevent or mitigate ice build-up is contrary to Continental and Lycoming's recommendations. Use of carb heat "bypasses" the air-filter and allows unfiltered air into the engine. It's not good for your engine to allow unfiltered air on a constant basis into your engine. That's why that put air filters in the system. Use Carb heat only as "recommended" by the engine manufacturer. Your use of carb heat is a self-made abuse of the system, and quite frankly, makes no sense. In over 50 years I've been flying reciprocating engines, I've neve heard of anyone recommending the use of carburetor heat the way you have just described. Engine manufacturers don't recommend the control power with carb- heat simply because it is "convenient". I certainly hope that no student pilot, or experienced pilot uses your recommendation for carburetor heat in airplanes. If a pilot needs to enrichen mixture, then use the mixture control. After all, it's not that inconvenient to screw in a few turns of the red knob. Please cite to any FAA handbook or any other authoritative source the recommendations for the use of carburetor heat in the way you have described. Rod Machado, if you are reading this, have you ever taught any of your students to keep the carb- heater on during cruise to "smoothen out the engine"?
@@daffidavitWhat using carb heat does is let you operate the engine at a higher density altitude than the airplane is experiencing. We aren't using full carb heat, but just a tiny amount. We don't use the carb heat down low in the smog, and people who use these techniques and have for years are seeing 2 and even 3 times the recommended TBOs...so unless you're using carb heat on dusty strips, there is PLENTY of evidence that is is NOT harmful. You can do the same "smoothing" with slight richening with the mixture control, but that adjustment is very sensitive and carb heat is far more convenient. You only need a little in any case. Furthermore, you're getting advice driven by Product Liability Lawyers. If you think it makes no sense, I'd advise you to look up the term "Dunning-Kruger" fallacy. You bought the party line and your smugness is obvious; now you need to actually find out what the people who have been doing this for years KNOW from experience. (If you haven't done it in all your 50 years, you have ZERO experience with the technique.) As I said: I'll go with the guys who use these techniques to cross oceans in single-engine airplanes and have been pleasantly surprised by the lack of fulfillment of such dire prophecies. Finally, as one who actually worked in a filtration lab at Southwest Research Institute, I can assure you that your air filter is very likely NOT performing as advertised anyway. So claiming that bypassing it at altitude is an "abuse" is just a sad bit of self-satisfying "gotcha" with no evidence to back it up. Id est, YOU are the one "not making sense". That "only two positions, on and off" as told by a manufacturing rep is good for satisfying people that want "easy answers", but frankly you should be ashamed of yourself. You just revealed yourself to be one not willing to actually _think._ I'm guessing you were trained by the military that didn't WANT pilots thinking for themselves with government equipment. A good parallel is how much resistance Lindbergh got when he told the P-38 pilots to run oversquare. Guys like you could never have gotten to Yamamoto. Thankfully they listened to what was regarded as heresy and found out they were wrong. It probably shortened the war and saved 10's of thousands of lives. And BTW- just because you've never heard of anyone doing it the way we do in 50 years of flying recips probably ALSO means you've been leaning incorrectly...just like they did for 50 years at Embry-Riddle. Turns out they were WRONG. _BIG TIME._ You might buy into the fallacy of an "Appeal to Authority", but the Emperor - and _you,_ have no Clothes on...
Would like to see the statistics on engine repairs/replacements, say, few years into this "new" procedure. Sounds like a fanciful perfect recipe for new and upcoming A&Ps looking for engine OH business ... as well as engine failure accidents. Green, young inexperienced pilots constantly jacking around with mixture controls?? Made to order burnt/blown valves, damaged cylinders/pistons. Flew many thousand hours behind Pratt 1340s. Only adjusted mixture during cruise at alititude. Only engine failure I ever had in a Queenaire, was a swallowed valve during climbout after I had but barely retarded mixture. Much of this ... based on last 75 years or so of recip aviation is information overload .... used to be, ONLY "leaning" of engines was after reaching cruise altitudes. So now .... all that flying, all those hours ... is WRONG??? Unless totally mishandled, very, very few engine problems due to mixture functions. If what you claim were true that and all that damaging to engines .... sure were a lot of airplanes that ran out TBOs with no problems!!
This FAA A&PIA, 2820549, Army Air Force 1952, Aircraft and And ENGINE school, Keesler Air Force Base, Mississippi. 43---7 ,1952 +. Moved to Japan, 52 ? Air crew WB-29 tail gun 32---7 weapons, Korean War, 2000hr,+ .Story: stationed Army AF in Japan, brown suits, Then in 1955, me in Japan The new created US Air Force Blue suits, with new B-29 -27 fuel injection engines replaced carb engines. Point me to the Aircraft, Gen , mil, it's in my diary. beat that Savvy ? 92, maintain my sons 172 at present. My whole story is boring. Thank you, for reading.
Great stuff. I just want to make 2 suggestions:
1) Add a full rich run-up before your lean run-up. This tests the fuel system (pumps, carburetor/injectors) at max flow/duty-cycle. Your lean run-up should take care of any spark-plug fouling worries.
2) Even for PowerPoint, 240p is too lean of an upload resolution.
This is the most useful pilot enlightenment channel on TH-cam
Thank you! We aim to please!
@@savvyaviation can you start the community where we will be changing ideas about aviation please, i am late to watch this video but its so usefull
Couldn't agree more...refreshing to hear this wisdom on max power...helped my 0300 feel much better all around 👍
Best leaning ROP/LOP instruction i have seen. Well done and should be mandatory watching for all pilots.
I cannot lie, I was afraid of leaning the mixture in my Arrow due to only having an EGT gauge. The POH also recommends that the mixture be left full rich below 5000 feet, which I’m seldom above unless I’m traveling. I’m glad I found this video, it goes against everything I was taught and almost everything the POH says - but I want what’s best for my engine
So have you been leaning the engine more. Do you notice any difference?
@@motogirlz101 I will find out in the annual next week when we pull the plugs. But so far so good
Sir, thank you for making such a comprehensive tutorial available to the general public. You have a wonderful teaching style that makes this data-heavy area (relatively) easy to understand.
Its a real shame this video only has 10k views
Maybe if the guy actually started talking about leaning aircraft's engine vs 7 minutes to tell us Embrey Riddle didn't do things right. This is an instructional video not story time.
@@foxtrot789 I haven't seen such a high horse in a long time. Why don't you try getting off of it and just be thankful Mike is kind enough to share this knowledge with us, free of charge?!!
The best information I’ve got on adjusting mixtures. Everybody is afraid to run lean of peak where I am at. Mike getting 200% TBO tells me he knows what he’s talking about Just getting ready to break in my newly rebuilt I/o 470 I’m going to do everything I can to follow all the advice to the letter
I just stumbled upon these Savvy Aviation videos and am really enjoying them as a no longer current but always a pilot kind of a guy. Mike’s approach to redlines is spot on. Reminds me of comments of a Mississippi River towboat captain who said of the red and green buoys marking the river channel: Those buoys don’t mark the end of safety. They mark the start of danger. Stay the hell away!!
Understanding Mike leaning method was great for my O320 Engine. It is clean, starts at the first attempt, with relative low fuel flow .
Wow. For me the best part was relating it to the Briggs and Stratton. I instantly thought of the old motorcycles I rode and got it
Great presentation and advice. One small correction: at 30:46 Bush says airspeed varies with the square root of power. Airspeed actually varies with the cube root of power, so 3% more power is only 1% faster, and 10% less power is only 3.5% slower.
For an intuitive explanation why, consider an airplane flying a distance D. Drag varies with the square of speed, so at twice the airspeed, there is 4 times as much drag. To go twice the speed, the airplane engine must make 4x the thrust. That means it does 4x the work over distance D. But at twice the speed, it's covering that distance in half the time. 4x the work in 1/2 the time is 8x the power. That is: power varies with the cube of airspeed.
No, the speaker is correct.
Power offsets drag in level flight, and form drag goes up quadratically with airspeed.
The discussion there was the relation of power to airspeed. You are discussing the relation of power over distance, which is the integral of airspeed - hence the discrepancy in the carrying the quadratic into a multiple.
@@chronikentertainment7856 Thrust (not power) offsets drag, and power is thrust * speed. So thrust goes up with the square of airspeed, as does drag. But power goes up with the cube of airspeed.
Simple example: consider an airplane that wants to fly twice as fast. Drag is 4 times higher, so the engine must produce 4 times the thrust. That is 4 times the work, over any given distance. But it covers that distance in half the time. Doing 4 times the work in half the time is 8 times the power.
So doubling the speed requires 4 times the thrust and 8 times the power. Thrust increases with the square of speed, power increases with the cube of speed.
@@michaelclements4664 Yes, you are correct, and clarified my error, thank you.
I’m learning in Colorado with home field at over 5,000 msl. Learned to lean day one.
The field I fly out of is 4,500 MSL and we have to climb to 7,500 or 8,500 to do maneuvers. I teach my students how to lean the first lesson.
Best aviation channel on TH-cam.
Thanks Mike. To date this has been the most informative lesson I've seen reference leaning. I've searched POH's, online sites and engine maintenance instructions and manuals. Really great stuff! Thanks.
Glad you found it useful~
@@savvyaviation Mike. I’ve flown by your words for decades. Love your books . Now. Loving Ask The Mechanics! One area where I am a little puzzled:
1. Stay out of the Red Fin (or box). 👍
2. Avoid high CHTs. 👍 Gotcha
So, I can be right at peak EGT but the CHTs stay happy at 380 or less with cowell flaps open.
Is it really ok to be at peak EGT as long as the CHTs stay cool??
Cessna 185F IO520 typically:
24hg/2400 RPM. Thanks 🙏
Amazing video. So much good knowledge on proper engine operation. I like many were trained in the super rich mindset on rentals but now as an owner of an ‘86 Mooney M20J with GAMI injectors, this has changed the way I operate. Luckily I am able to keep below 380c even in the climb and LOP at altitude the CHTs are in the low 300’s. Running great so far at around 150 ktas and around 8.5 gph.
Hey Mike - fantastic videos. On this one though: wouldn't you want to go full rich for landing...since it might be a go-round (takeoff equivalent)? Obviously adjusted for high density altitude cases...
1:18 go around is mentioned
I would love to run LOP butI have a normally aspirated PPonk 275hp engine in my 182. I also have an EDM830 gauge that show all the temps on each cylinder. Well the differential is 100deg or so on EGTs and 25deg on CHTs. I have tried the carb heat trick but still get 80 deg differential. If I lean so all the cylinders are happily cool the engine runs rough.
Great information, and a very understandable presentation style. I looked up Lycoming Service Instruction 1497A and it specifically addresses IO-360-L2A engines. I know you discuss how to lean for carburated engines, but has Lycoming ever released any service instructions or other documentation that addresses more current leaning procedures on other engines? In other words, is there Lycoming documentation to support these techniques on my 0-320-E2D?
I have the exact same question.
I know it’s been a while since you all have asked your question, but Lycoming Service instruction 1094D covers leaning procedures for all Lycoming opposed series engines.
question about taking off in a simple plane. your basic checklist from 15:13 says lean in a climb above 3,000'. But before that you said full rich should only only be used for a maximum of a minute or two. Well, it will take a lot more than 2 minutes to climb to 3,000' from a sea level airport in a 172. Whatre your thoughts on that?
This is great videos! However I can only see it in 240 resulotion which makes the diagrams hard to read. Any chance they can be put out on the tube again witv 1080 resulotion 🙏🙏
The last time I flew a piston was like 30 years ago. My plane didn't have egt and cht guages and I'd lean only when I'd reach cruising alt by pulling back on the mixture till the engine runs rough then push it back a bit. Wondering if this is what LOP is. anyone? Thanks!
I’ve got a 1975 172M with a 180hp O360A4M. It does have a simple EGT but nothing else. I’m a little confused on what he means by engine complaining. While leaning I notice an rpm drop but still smooth operation during the leaning process. If I continue, I get noticeable roughness. Is the start of the RPM drop the complaint or is it the actual rough running?
1:04:15: 30" manifold pressure EGT is lower than 25" manifold pressure EGT because 30" is more efficient, more work gets done, more of the available chemical energy is consumed creating useful work resulting in lower waste energy thus lower EGT because EGT is a measure of waste energy as you said.
Excellent information. Every pilot should watch this and learn.
One small but very important correction: dropping a lit match into a bucket of fuel and having the match go out only works with Diesel or similar (low volatility, no vapor cloud forms.) If you try that with a bucket of gasoline as suggested in this video, you will get a very dramatic fireball (and maybe 3rd degree burns), as gasoline is a volatile fuel and it will form a vapor cloud. The match will ignite the vapor cloud, which may be big enough that it envelopes you, resulting in a big flareup, and igniting the liquid gas in the bucket.
Other than that, good video.
No, this is not necessarily correct, sorry. The speaker is indeed right - take it from me as a once stupidly adventurous teenager. (please don't try this unless under controlled conditions).
At higher temperatures where vapour clouds form, yes, a fuel surface may ignite. But at average room temperature a "bucket" of avgas will not ignite. Also, liquids in themselves will not burn (there is no molecular contact to sufficient oxygen) - once the vapour above a fuel surface has ignited, it will heat the surface to release more vapour, thus sustaining the fire.
It's the same reason we need choke or prime to start our engines when cold - the fuel has condensed on the cylinder walls, so does not want to ignite as a liquid. We need to prime the system to force a higher fuel vapour / air mixture within the cylinder for the first ignition. After that, temperatures increase and fuel no longer condenses to the cylinder wall.
When I was a student pilot; it made me nervous messing with red knob in flight as it was a mental "kill engine" knob. Lol was afraid I would mess up and kill engine. 😁 My instructors never spent much time on leaning.
I think this is a common problem with flight instruction, especially at low altitude schools. Partly to simplify early lessons I'm sure. They would also rather clean fouled plugs than to replace holed pistons caused by incorrect leaning of noobs.
On descent, i notice you can go really lean without causing roughness to the engine (due to very little power being required since you're going "downhill"). Is that ok? I assume the biggest risk is not remembering to enrichen when you get into the pattern/final. Just seems like a no-brainer way to save more gas. Mr Busch, I'd love your thoughts on this. I fly a 180HP Lycoming o-360 in a 1965 Mooney M20C.
instaBlaster.
Outstanding video! You are doing the Lord’s work 😊
In the very beginning, it says lean to roughness then enrich. So if no CHT gauge, isnt possible to be in the red box? My Cherokee 6-260 doesnt have CHT. So if I lean to roughness, then enrich till 70-100 degrees ROP, isnt this what I was taught 30 years ago? So many questions..
There's no CHT gauge in the planes I fly also, and it's not easy to operate LOP on them without engine roughness. So the goal (in my mind) is to operate at a power level which is low enough that I'm not in danger of running in the red box. Just refer to your POH for power charts. If you run under 70% power it should be pretty much impossible to be in the red box. In any case, I think, at 70% power, stoichiometric (or slightly LOP) is better than 70-100 ROP, as you will save a lot of fuel, run cleaner, and sacrifice very little airspeed.
Most people have gotten the message about leaning while taxiing, if for no other reason than it prevents having to do the plug cleaning shuffle during runup. I'm always leery of leaning while climbing or anything involving full power. I can totally understand leaning when the DA is high but again, how much is safe vs what will hurt the engine.
My favorite leaning video
Thanks Mike, great instructional video. Really pulls it all together in an easy to take in, digestible and comprehensive package. I learned a lot from this, very quickly.
Is there anywhere we can get a nice clear printable copy of all the charts you use to explain it?
Love to hear your thoughts on an engine like a Rotax 915is. I fly a Sling Tsi and I have full FADEC. I can run Full Throttle forever, but that sucks gas. So I usually back of until it goes LOP, and have a choice of 5400 RPM at about 8.4 GPH or 5000 RPM at 7.3 GPH. I get about 18 mpg at the higher power and 21 mpg at the slower setting. Max FF is about 11 GPH. This video was very helpful in understanding the operating regions. I have an advantage with fluid cooled heads, so CHT is a non-issue (I think). Thanks for the detailed info.
Nobody teach these technic. Thank you very much
As always, great explanation! I am reading your books and I am convinced you are one of the best experts out there. BTW: I own a Landrover Series II, built 1960. I know how to handle a choke :)
I was taught on o320 to lean to stumble and then 6 half turns in. Never really knew why and didn't notice much difference from say 2-3 turns in. So I've been running too rich I guess but not by much. I have leaned again at say ~10,000' after sea level departure and never only noticed say a 1-2 turn difference.
update - a&p's have told me now that Mike's recommended basically as lean as possible is too lean for Lycomings and ends up a bit hot EGT
@@brentdavidson1maybe but most a&ps have no concept of the real world of flying. They are simply not taught anything close to a detailed explanation like Mike teaches. Totally depends on their background. If they are farm boys or grew up working on engines this is very basic and easy to understand. If they are city boys that never changed oil before a&p school, not so much. A&P license is just a certificate to learn sadly. I was shocked when I went through school. They prepare people more for the airlines than GA. Also, if you study Mike's material, the safe and easy way to truly get much more than tbo out of your engine, you need to have an engine monitor. Takes all the guesswork out of the equation. His advice is always about stock engines too. Even more important to have a monitor on modified engines.
Is this good for lycoming and Continental? Looking at a 172 with 0300
Excellent lecture. Thank you.
Most people were trained on four cylinder engines with carburettors which are notorious for having unequal pressures in the cylinders. No seperate EGT and CHT temps per cylinder so very difficult to lean adequately.
Hi Mike. My plane has a 285hp radial engine. I fly aerobatics mostly with high power settings. Is there any special considerations re leaning?
I fly the Cessna 152, with the O-235 which also have a cht gauge installed. I find that at even the 50 degrees rich of peak (which is the the recommended POH leaning technique) the cht does not get above 340 even at 75% power. Is this just because it is lower power and only four cylinders? I don’t see an issue of leaning rich of peak because of this. Does anyone else use a different leaning technique for engines like the o-235?
But why would you want to run the engine at that mixture setting if it's neither best power neither best economy setting? To get something in between? But you're getting this compromise where it's most stressful to the engine. I would choose what I want (speed or economy) and set the mixture accordingly.
Is LOP in a carbureted engine equivalent to leaning to minimum (non rough) fuel consumption in an aircraft with fuel flow gage?
Most modern engines(like post ww2) automatically adjust ignition timing based on at least RPM or throttle position often both. The 20degrees the mechanic sets is the reference point at idle, if you keep the timing light on and rev the engine you can see the timing shift 10 or 15 degrees. I don't know if this applies to an L-320 L-360 type engine.
@@brettdavies-young7102 I suppose that is reasonable considering they operate most of the time in a moderately narrow RPM and load range and fixed anything is more reliable than adjustable. The trade off is reduced efficiency from idle to low-cruise manifold pressures[high altitude] with retarded timing, or reduced max takeoff power without knocking with more advanced timing.
@@mytech6779 What is even MORE "reasonable" is not adding a mechanical variable timing feature that would introduce another possible failure mode. That's not to say that I for one would turn my nose up at a _cockpit adjustable_ timing control, but most pilots probably wouldn't make the effort to master it's use.
This doesn't happen on continental and Lycoming engines. These engines are built from the same sand cast lineage from 120 years ago
@@craigwall9536 The rotax 915 burns 7 gph in cruise and is turbanormalized. One lever FADEC control for engine and constant speed prop, mixture auto runs lean of peak below 80% power. They have computer controlled direct injection and spark ignition controls.
Are those older webinars on you tube
Only holidayed for a few days in Florida from the UK. But the humidity there must produce very rich mixtures as Embry experienced. No wonder the engines were rough. Also if you have problems starting, usually pilots start over priming, get the mag switch checked out. Seen quite a few where cranking position was earthing both mags, no wonder the engine wouldn't start until the key was backed off slightly. If in doubt, just remove both mag wires of the key switch and see if it starts any easier.
What is LOP? Is that mean low oil pressure? On the subject of leaning, I noticed some engines like the ones in a Beachcraft bonanza allows you to run lean of peak. The. Warrior I fly states to run the engine wide open and adjust your RPM with leaning to provide cruise RPM. I noticed in the Cessna 172R POH says extensive running, lean of peak is prohibited, and that statement is done in bold face. It’s all confusing of who is correct and who is not.
Excellent! If I had seen this video, I guess I wouldn't have needed to buy your book 😋
Do you have a discussion about leaning engine (IO540-AB1a5) or similar with only basic single cylinder CHT gauge and basic EGT. Lycoming says its fine to operate at max EGT below 75%, but people tell me its not safe because I don't have a sensor on each cylinder. Lycoming also has recommendation for leaning without CHT or EGT by just leaning to leanest setting that results in smooth operation. What are your thoughts on that method?
Mike - when talking about turbocharged engines you say, "Controls full forward except the 182T... manual wastegate/etc." I fly a Pa-44-180T that has a manual wastegate as well. So, throttle to desired MP rather than full forward? (Great videos and great service to the community!)
Only problem with not doing full rich on landing is that if you're part of a club or school, the CFI is either going to force full rich because of their own primacy, or the school/club otherwise prohibits that method of landing for checkouts, proficiency checks, and refreshing. So unless you do this solo in the pattern for practice you probably won't get to wriggle out of full rich mode reflex. You own your own plane, probably not so much a problem.
The CFI will "unlearn" the practice when you're with them, and you'll have to "re-learn" landing leaner solo.
Also, I suggest turning off comments if you record a cockpit view and the peanut gallery sees the leaned mixture during landing.
My C182 (2005) PoH recommends cruise at 50 ROP and that isn't an old aircraft, I don't understand why?
Depends on what you are trying to accomplish. Best power or best economy.
Your PoH recommends that because they can't be sure you've got even mixture distribution and they don't want you to have one hot cylinder and not know it because the CHT probe is on the wrong cylinder. IOW's it's a "product liability" issue- read that as "lawyers" and "nanny state". The cure is to have at least CHT on every cylinder and run with the throttle wide open and significantly LOP.
I run mine at 570 degrees all day... My engines only last 400 hours before they need to be rebuilt and 2 of them have had catastrophic failure. You think this is why?
I was just trolling a little bit lol
Wow! A lot of very useful information in all your presentations. Since there wasn't much time to address questions... When you look at the EGT gauge for the leaning, do you do it with the hottest cylinder, coldest, first to peak, last to peak, or doesn't matter? I'm guessing that not all cylinders will be peaking at the same mixture setting.
Hottest cylinder.
I am a little confused. I typically fly airplanes with just oil temp guage if I am lucky I have a functional egt. I Typically lean to roughness than richen till engine runs smooth. Would this likely be rich or lean of peak ? Is lean of peak beyond that initial engine roughness?
What happens if you reach engine roughness before peak egt temp on the older style egt guage?
Another one of Mike’s videos regarding CHT’s he states that running a lycoming in normal cruise up to 420f is okay. I’m not sure why he is so hard over on the 380F in this video. Hopefully he can comment and rectify the discrepancy. Generally I find his videos extremely educational.
Great video
Great presentation, I’m a first time airplane owner and I’ve been slowly digesting all your webinars, books, articles. I do have one question, you mention leaning for max RPM, how does one do that without these charts? My aircraft (C120 w/O290) only has a single EGT/CHT gauge. I’d like to get an analyzer at some point, but for now what’s the best method?
Thanks for the great content.
You set maximum RPM by looking at the tachometer.
You stated that full rich should only be during startup and takeoff below density altitude 3000 and only briefly. What if you're doing closed traffic work in a pattern that has a density altitude below 3000? You'll definitely be there longer than a few minutes rich. Are you leaning on downwind and then enriching moments later per poh (C-172)? I agree it's best to lean when you're cruising and have altitude but in the pattern that slight engine roughness during leaning seems like you'd be asking for trouble. Curious on this because I've cleared fouling on runup only to have a problem on my 5th takeoff roll (closed traffic work). Admittedly I may not have done the foul clearing as
long as I should have but still curious for an answer to my questions above....thanks in advance...
That's a very interesting point. Maybe it's a good idea to leave the traffic pattern for some time to "clean the plugs" after a few touch and gos. Personally, I would avoid this extra workload of setting the mixture for each pattern. At some point something will go wrong... right?
@@LeantoPeak Yes, leaving the pattern would have been better. My problem at the time was my radio stack was legacy 1978 172N with 1 mk-e replacing an RT-385. Leagacy transponder and tailbeacon was the only thing working.. I was reduced to handheld. I couldn't leave traffic pattern with that setup. I decided to fly plane in pattern just to keep oil circulating and tires from dry rotting in the hanger. I've been doing that for the past several months. In the interim I've discovered that getting oil up to temp at 1000rpm and leaning to peak rpm works. I asked my A&P if that is ok. He said lycomings preferred run-up procedure is different than the POH and close to what I was doing.
Do you know anything about that?
Btw...New stack delivered just waiting on install.
@@muhammadsteinberg gotcha. Enjoy the new stack! I wouldn't know, I'm just a noob pilot flying rentals, but what you mention makes a lot of sense to me and sounds healthier to the engine compared to traffic patterns. Or maybe you could remain in the pattern but maintain altitude (like simulating a go-around or simulating the runway was occupied). The only difference of running it up on the ground would be cooling, but if power is not excessive it should be fine. Hard to say for sure without CHT gauges though... cheers happy flying!!!
What happens if I don't get any engine roughness even when leaning aggressively? I'm going full throttle and then setting the mixture to get the power setting I want. Does that make sense? Cheers.
I used to use a clothes peg behind the knob to make it easy to set. Albeit on a simple aircraft with a c90.
Is it possible to operate safely LOP without a CHT gauge?
Yes, by operating at 70% power or less.
Should I change anything if I don’t have a CHT gauge in my aircraft? Running a lycoming 540 in a Cherokee 235
As Mike said, use rpm peaks or lean to acceptable roughness. I've found that adding carb heat in cruise helps smooth out many Cherokee engines. Works for the 320' 360, and also 540 in my Pawnee.
@@ricklafford8993 How long do you keep the carb heater on when you do this?
Some models of Lycomings have _rotten_ mixture distribution (it depends on the intake manifold and the position or angle of the throttle plate). If nothing else, get 6 CHT thermocouples and one gauge and a rotary switch so you can look at them all. And then actually pay attention to it!
Very Good thanks you Mike
I've heard it's neigh impossible to properly go Lean of Peak with a carbureted engine. Is that true? How much harder is it to properly go LOP carb vs injected?
In the planes I fly it's quite hard indeed. I feel as soon as EGT has peaked, if I try to go leaner immediately it runs rough. Maybe it means it didn't even reach stoichiometric and it's already running rough.
@@DylanClements98 so are we supposed to lean past the roughness to get to lean of peak or richen at the roughness till it runs smooth
Why not put a constant speed prop in a 172 R or S that already has an IO 360 in it? Many light twins have constant speed prop versions of this engine
expense up front and maintenance, and complex endorsement, and more stuff to fail.
@@mytech6779 Not to mention weight and the now improper loads on the motor mount vibration isolators because of the added weight out at the very front of the engine.
Mike, I didn't understand one thing that's maybe answered in the subsequent classes. Are you ONLY using CHT's to lean, or are you starting with peak EGT (such as using a "lean find function" on the engine monitor) and then leaning from there using CHTs and fuel flow? Thanks for the great class!
Never mind Mike...watched your advanced class and read a couple of your articles and you definitely answer that thoroughly. Thanks for the great information you put out there.
Thank you!
20yr firefighter and safety guy here… The gasoline bucket thing is something you shouldn’t try lol. This would be true for kerosene… not for gasoline. Flashpoint is drastically different between those.
Going farther is a lot better if you’re an aircraft owner. If you’re an aircraft renter and you’re paying on the Hobbs meter then I would think you would want to go faster.
Pretty sure you’re also supposed to be full rich when operating over 75% power on most piston engines. That example around the 50 min mark should be full rich if it’s being used I would think. Then again I’ve mostly flown Lycomings so maybe Continental is different.
At 10,000 ft can I just run at stoichionetric without harm to the engine
Refer to your POH for power charts. If you are under 70% power you should be fine to run stoichiometric.
Dumb question...but I just don't get why they can't make airplanes lean like a modern car. Is it because a plane can gain elevation faster than a car on the steepest road? So... we don't make computers fast enough to handle this?
I have 30 years programming computers and just learning to fly. These are the questions that my CFI hates.
The electronic solutions in your car don't have to be certified by the FAA. Probably much easier and cost effective to have the simple tried and true mechanical equipment certified.
Isn't leaning for Max rpm setting the hottest cylinder temps? I was told that's bad.
Im not Saavy or a mechanic but ill try. In the run up you are running at a 1700-2000 rpm which should put most airplanes well below the "red box" + it helps get the engine warmer. Also, the hottest point is typically about 50 degrees rich (egt) of peak. Best power is 75-100 rich of peak egt. I believe what he is saying is that the engine is better off leaning the mixture tell just before its running rough than running 50 degrees rich of peak egt (which is what most engine monitors aim at).
@@BonanzaPilot Your analysis seems to be consistent with the chart at the 29:25 time mark. Best power on the chart is slightly rich of peak mixture. Even peak mixture is slightly rich of stoichiometric mixture, but best power is slight rich of that.
I watch this, especially the part about the timing of compression, ignition, expansion, crank angles, etc. and the coordination with the other cylinders, and I think, 25-50 years from now, people will look back and say, "OMG, those old IC plane engines were such a complicated mess, teetering on the edge of failure… our electric motors are so much simpler, lighter, more efficient, with fewer components, and easy to manage and maintain!!"
The batteries or electricity generation will be the new failure points (bombs)
Every summer, the school's planes will hardly idle due to the fouling, drives me nuts. Takes 3 minutes of extra lean runup time just to clear it up. They all just point to the 40 year old manuals and claim legal liability. I shake my head.
Just remembered they had a plane that was running very hot, oil temperature, in cruise. And I was like "hey I want to try leaning it I have a hunch that might be the problem", but the instructor was all "no richness makes it run cooler and we are only at 2000 feet". To this day I think the issue was either extreme excess fuel washing the oil off the cylinders and causing less lubricity, or that the throttle was set too high for the airspeed to make up for the reduced power due to incorrect mixture.
3min to correct fouled plugs = 0.05 Hobbs = $$ for the school :-)
15:03 The minimal leaning checklist
There's one situation you didn't talk about (although you got close to it later), and that's the high-altitude go-around. How would you lean for this? You don't have the luxury of being able to lean for maximum RPM while you're descending and entering the pattern, so what do you do? All you know for certain is you don't want to go full rich. Could you, say, lean for pattern altitude (whatever that entails), then go half a turn, or a full turn, richer, or maybe just leave it set for pattern altitude?
During a high-altitude go-around with a normally-aspirated engine, the engine is only putting out cruise power (75% or less), so leaning is no different than what you'd do in cruise.
If the engine is turbocharged, it "thinks" it's at sea level, so you'd go full-rich just as you would at takeoff.
Hope this helps. -Mike
i was too afraid of leaning 😂once i was flying with old and bold instructor he saw me doing it very slowly and he pulled it all the way up and pushed it back .. since propeller was windmilling nothing actually happens u get back the engine . To stop windmilling ur speed should be somewhere near your stol speed in fixed pitch prop
What a boat load of information. I believe most general aviation pilots are oblivious to any of this detailed information. I once a stearman and the POH was even counter to Continental's start up procedure. I think all of this misinformation centered around the US Army Air Corps need to put pilots in aircraft before they grew long grey beards and fathered a dozen off spring. This level of mechanics back then was unheard of. We needed pilots converted from farm boys, not from physicists.
If your engine oil gets black quickly , after an oil change , you are running it too rich.........carbon goes out the exhaust as dark unburnt fuel and the piston rings are scraping carbon off the cylinder walls and loading up the lube oil with carbon.........diesel lube oil gets black quick for this reason because the carbon from combustion passes the piston rings and fills the oil up with carbon..
Also you can pull a plug and check the color. Black and dusty is not good - too rich.
@@ricklafford8993 Once you get your head around leaning properly WITH ADEQUATE TEMP INSTRUMENTATION, you'll leave all that carbon fouling behind.
I’ve unlearned a lot over the years
I thought that stoich. was 14.7 to 1,
Cessna 140 doesn’t have mixture control.
Oxygen sensors in the exhaust and positive mixture control as per all automobiles now would be the answer not having 1930s tractor carbs and constant spray fuel injection wasting fuel and demanding constant attention from pilots that do not know how to do it anyway.
Not as long as the FAA is run by former airline executives. They want the bicycles off the interstate.
Mike might be slightly misinformed about the constant LOP condition of modern cars. The system there only cares about the maximum life of the catalytic converter doing the emissions clean up of the exhaust gases. The mixture is constantly varied lean and then rich again to charge the converter with oxygen and then to consume that stored oxygen. Mileage takes a distant back seat to emissions at all cost and always. If the converter fails to show expected results of this constant flushing of rich and then lean mixtures, it sets a check engine light code for failed catalytic converter and in some states you can not then get your registration for the vehicle renewed again until the check engine light problem has been fixed. Further, under full throttle acceleration, the emissions rule book is thrown out the window and no use is made of the O2 sensors, the computer wings it with a set of known engine parameters as long as that foot feed is mashed to the floor. You'll need a vastly differently programmed system for airframe work to the one found in a modern car.
@@jjohnston94 Well bravo to them and their pilot shortage
Your interpretation of the ragged curve at the ICP peak is mistaken- the "instability" you think you see there is NOT _primarily_ caused by "shock waves bouncing around", rather it is the result of piston ring sealing beginning to fail and the onset of "ring flutter" due to excessive ICP. This is most noticeable in the 30" versus 25" m.p. plot, where at 30" m.p. the rings have simply been overcome by pressure and there is a sudden pressure reduction due to leakage. If you happened to be monitoring cylinder blow-by coming out of the crankcase, you would have seen a jump in the volume at that setting. (It is not the "measured" pressure alone doing this; the detonation actually would push the pressure spike MUCH higher if the rings hadn't vented, so yes, the detonation or pre-ignition is causative in large part. But the raggedness in the pressure trace is due to the rings venting/sealing/venting/sealing as they go unstable in their grooves and lands.)
How do I know this? I did an internal research project at Southwest Research Institute investigating this very phenomenon. Aside from the excessive heating, this ALSO blows the oil film out of the ring grooves and off the cylinder walls and leads to a large increase in cylinder wear rate. It also _breaks piston rings_ .
Your interpretation of why the EGT goes *down* at the higher manifold pressure when pre-ignition or detonation is present is also _mistaken_ : it goes down because NOW some of the exhaust is blow-by going out through the crankcase breather and bypassing the EGT probe.
Very interesting, Craig. Please: what would your technique be for leaning a Continental IO-470C (at cruise) for most efficient operation (without an engine analyzer)? Thank you!
@@johnrltr Without _knowing_ at least the CHTs for EVERY cylinder, you're basically in a fist-fight with a poltergeist. Having EGTs for every cylinder is even better, but not strictly necessary. Maximum engine economy is at roughly 50 degrees lean of peak, but in fact "most efficient operation" is a little vague- for me, two things are important: like Mike says, lean to roughness _GIVEN KNOWN CYLINDER TEMPS_ (which can be known by a temporarily installed set of CHT probes) AND by having the throttle WIDE OPEN so you know that the throttle plate isn't messing up the mixture distribution and you've got minimum pumping losses.
At that point, you can choose your level of roughness: if you've got a tailwind, leaning past "max engine economy mixture" is even better. If you're going upwind, that max econ mixture is the best choice.
Now I'm giving you MY logic, but it's ALSO based on flying at the Carsten Speed (or Norris Point), which is the speed that is faster than max range speed; it's the max _speed/drag_ - 1.316 times max L/D IAS at ANY altitude- you've got a 21% speed increase for a 15% drag increase. Faster is less efficient; you ask about max engine efficiency but I'M giving you the conditions to optimize the engine _and_ the aerodynamics _simultaneously._ After that, every foot of altitude is giving you a TAS bump, and so going high and getting the fuel burn down where you can go non-stop is MY definition of "efficiency". And that may be significantly LEANER than "max fuel economy", since THAT refers only to ENGINE operation.
@@craigwall9536 Thanks. I"m close to breaking the piggy bank for an analyzer; what's your opinion of the JPI EDM 700 for an entry level?
@@johnrltr I have no opinion at all on any brand or model of "analyzer"; my approach is to use a system that can be used on any aircraft with _no electrical system at all:_ I have four dual temp gauges- 2 are dual CHTs and 2 are dual EGTs, arranged so that each stack of 2 dual gauges have the needles pointing at each other, with the top two needles reporting the front two cylinders and bottom two the rear cylinders. (It's a cluster of four 2 1/8th" instruments.)
This gives a visual layout that mimics the layout of the jugs in my C-85. A stack for the EGT and stack for the CHT...and all of it run straight from the thermocouples to the D'Arsonval meter movements. No other connections. You could do this in ANY aircraft.
Let me tell you: it's VERY comforting to just glance over and see all those needles behaving themselves, everything leveled out and pointing straight across to each other. These are simple Westach gauges right out of the Wicks catalog.
The Analyzers are wonderful because you can program them to alert you, select a particular cylinder to act as reference, etc.. But they cost 2 or 3 times what my setup did (actually less because I found second hand gauges and confirmed their operation myself) and they require an electrical system. I don't need the alert feature anyway because I glance over during my panel scans and as long as the needles are behaving and the CHT is below 400, we're good.
You can do the same thing with single gauges and 4-position switches, but then you have to work at it. And most people will find the hottest cylinder and leave the switch there, but if something changed in a different cylinder you wouldn't know it.
But it's worth repeating: EGT for all practical purposes means basically nothing- all that matters is CHT. EGT is useful if you need to know where peak mixture is, but if you simply lean aggressively to get past peak and richen from the LOP side, that's all you need and you can do that by ear /feel. Watch Mike's video on advanced leaning concepts and the Red Box concept.
Finally...and you probably don't want to hear this... once you _know_ that the cylinders are running evenly, you don't need ANY temp gauges if you lean aggressively. You do, however, lose the monitoring function so that only works if nothing changes. I prefer to have them because sometimes baffling leaks open up or birds build nests back where you cant see them.
(I've even swallowed toilet paper during a "cutting session" and the temp rises are immediate...)
Edit: One other thing: If you do get an Analyzer, try to get one that automatically adds the "cold junction" correction. With my gauges I have to mentally add the cold junction temp to the indication to get the actual temp. That's only necessary for the CHT readings, but if the gauge says 350F and the cold junction is at 50F, the cylinder temp is 400F. I think most digital Analyzers perform that correction for you, but probably not all and you really need to know whether it does or not. With the EGT you don't care what the actual temp is; you just need to detect the peak and know which side you're on.
Remember: everything gets better at W.O.T. That's going to be the condition with the least pumping losses AND the best mixture distribution..._usually._ Lycomings are sometimes lopsided no matter what you do. And if it's an injected engine, you may have to do some injector-matching to get things right. Above all else, do NOT tolerate leaking baffles!
A lot of people say that Mike Busch's stuff is bullsh!t and he wrote a book to make $$. My CFI says, that one should go 50* Fahrenheit ROP and keep an eye on the CHT temps, especially if it's a normally aspirated carburetor airplane and you just can't precisely apply LOP principle without an engine monitor. Also, your trip at the end of the day will cost higher compared to your fuel savings, because you're wasting your time between overhaul of the engine plus other parts that have limited resources, as well as your personal time (considering that people buy personal airplanes to go places faster).
What do you say?___ I left a 'thumbs up' under the video.
Shouldn't throttle be adjusted to obtain equal airspeed to properly compare lean vs rich fuel flow?
A 5% reduction in speed is about a 14% reduction in power needed, based on simple parasitic drag. (probably more like -10% once figuring in the increase in induced drag but of course induced is highly dependent on loading and wing design)
The point is that you can't change speed and attribute the change in fuel flow to leaning, that is just bad science and engineering.
To be sure the plane I fly is not designed to cruise at WOT at the altitudes common in my area.
So the plane was not designed to fly at the altitudes common in your area. Just kidding. Some people will argue that it makes more sense to leave throttle wide open, and adjust mixture to get the power (RPM) you want. So basically, let the engine get as much air as it can, just control how much fuel you're pouring into it. Makes sense to me, as long as it's not running too rough. Otherwise, I would agree with you.
@@LeantoPeak Yeah I worded it a bit odd. Basically all the VFR here is trapped at about 3000msl under a class B shelf unless we climb high enough to get over 8-9000ft to get above the mountains boxing in the area.
Unlimited air and adjusting fuel to get power is how turbines operate and to a certain degree the Diesel cycle, but I was limiting my comments to Otto cycle engines. Just attempting to keep the results as apples to apples as practical. (Both gas turbines and Diesels naturally operate on the extreme lean side.)
@@mytech6779 yeah was just kidding. I think you could have a look at this webinar from Mike, he talks about some nice numbers like knot/gallon and such - th-cam.com/video/ZBr6kjvfzio/w-d-xo.html
When you ask the EGT question there is an assumption on the listeners part that you haven't changed anything else (such as ignition timing). So your question and provided answer are disingenuous.
Leaning made simple in only 91 short minutes.
The I'm an idiot with no attention span version in somewhere else on youtube
Brett Davies true, thanks and Tomias Thexder: lolol
!) The like button doesn't work.
2) I get over 1,100 miles out of a Cesna 182T by using this technique. ...albeit in FS2020! ;)
Slow climb (500 FPM) to 15k lean of peak then cruise to near destination for a free ride back down.
AoA between 1 and 0 is pretty good. Monitoring and adjusting EGT pretty much the whole way up.
in the sim, the 182T is happy as a clam up to 20K. 22K is a bit too far.
Real life? Sorry, I haven't a clue! LoL
Many of the c75,85,90 engines have no mixture control and spend their entire lives at full rich
pull it back till it runs rough,,, add a bit ,, saved ya 90 mins lol
E-225 = 26 BTDC...
Stoichiometric
Photosynthesis.
I'd only lean to RPM drop before setting for cruise. Engine roughness is scary.
Try adding carb heat.
@@ricklafford8993 For how much time?
@@daffidavit No, no- LEAVE it on, because that richens the mixture. As for "scary engine roughness", if the temps are even, the engine is happy even if you aren't. Rick wasn't kidding- I actually now control power in cruise with carb heat because it's the most convenient way to adjust mixture in cruise. Just "lean to acceptable roughness" and then smooth it out a little with carb heat if you want a bit of climb. I run with the throttle WIDE OPEN and control power with mixture- but don't even think about doing it that way UNLESS YOU'VE GOT TEMP PROBES ON EVERY CYLINDER. And BTW- you can get used to a bit of roughness once you figure out that every cylinder is experiencing the SAME degree of roughness, your CHTs are down below 400, and your fuel burn is WAY down. Notice that Rick said ADD carb heat, not PULL carb heat- meaning just add only what is needed to lower the air mass flow to richen slightly; you're not trying to clear ice.
@@craigwall9536 As told to me once by a manufacturing rep. of Continental engines, "there are only two positions for carb heat, on and off". Use of the carb heater for any other purpose other than to prevent or mitigate ice build-up is contrary to Continental and Lycoming's recommendations. Use of carb heat "bypasses" the air-filter and allows unfiltered air into the engine. It's not good for your engine to allow unfiltered air on a constant basis into your engine. That's why that put air filters in the system. Use Carb heat only as "recommended" by the engine manufacturer.
Your use of carb heat is a self-made abuse of the system, and quite frankly, makes no sense. In over 50 years I've been flying reciprocating engines, I've neve heard of anyone recommending the use of carburetor heat the way you have just described. Engine manufacturers don't recommend the control power with carb- heat simply because it is "convenient". I certainly hope that no student pilot, or experienced pilot uses your recommendation for carburetor heat in airplanes. If a pilot needs to enrichen mixture, then use the mixture control. After all, it's not that inconvenient to screw in a few turns of the red knob.
Please cite to any FAA handbook or any other authoritative source the recommendations for the use of carburetor heat in the way you have described. Rod Machado, if you are reading this, have you ever taught any of your students to keep the carb- heater on during cruise to "smoothen out the engine"?
@@daffidavitWhat using carb heat does is let you operate the engine at a higher density altitude than the airplane is experiencing. We aren't using full carb heat, but just a tiny amount. We don't use the carb heat down low in the smog, and people who use these techniques and have for years are seeing 2 and even 3 times the recommended TBOs...so unless you're using carb heat on dusty strips, there is PLENTY of evidence that is is NOT harmful.
You can do the same "smoothing" with slight richening with the mixture control, but that adjustment is very sensitive and carb heat is far more convenient. You only need a little in any case.
Furthermore, you're getting advice driven by Product Liability Lawyers. If you think it makes no sense, I'd advise you to look up the term "Dunning-Kruger" fallacy. You bought the party line and your smugness is obvious; now you need to actually find out what the people who have been doing this for years KNOW from experience. (If you haven't done it in all your 50 years, you have ZERO experience with the technique.) As I said: I'll go with the guys who use these techniques to cross oceans in single-engine airplanes and have been pleasantly surprised by the lack of fulfillment of such dire prophecies.
Finally, as one who actually worked in a filtration lab at Southwest Research Institute, I can assure you that your air filter is very likely NOT performing as advertised anyway. So claiming that bypassing it at altitude is an "abuse" is just a sad bit of self-satisfying "gotcha" with no evidence to back it up. Id est, YOU are the one "not making sense".
That "only two positions, on and off" as told by a manufacturing rep is good for satisfying people that want "easy answers", but frankly you should be ashamed of yourself. You just revealed yourself to be one not willing to actually _think._ I'm guessing you were trained by the military that didn't WANT pilots thinking for themselves with government equipment. A good parallel is how much resistance Lindbergh got when he told the P-38 pilots to run oversquare. Guys like you could never have gotten to Yamamoto. Thankfully they listened to what was regarded as heresy and found out they were wrong. It probably shortened the war and saved 10's of thousands of lives.
And BTW- just because you've never heard of anyone doing it the way we do in 50 years of flying recips probably ALSO means you've been leaning incorrectly...just like they did for 50 years at Embry-Riddle. Turns out they were WRONG. _BIG TIME._ You might buy into the fallacy of an "Appeal to Authority", but the Emperor - and _you,_ have no Clothes on...
Would like to see the statistics on engine repairs/replacements, say, few years into this "new" procedure. Sounds like a fanciful perfect recipe for new and upcoming A&Ps looking for engine OH business ... as well as engine failure accidents. Green, young inexperienced pilots constantly jacking around with mixture controls?? Made to order burnt/blown valves, damaged cylinders/pistons. Flew many thousand hours behind Pratt 1340s. Only adjusted mixture during cruise at alititude. Only engine failure I ever had in a Queenaire, was a swallowed valve during climbout after I had but barely retarded mixture. Much of this ... based on last 75 years or so of recip aviation is information overload .... used to be, ONLY "leaning" of engines was after reaching cruise altitudes. So now .... all that flying, all those hours ... is WRONG??? Unless totally mishandled, very, very few engine problems due to mixture functions. If what you claim were true that and all that damaging to engines .... sure were a lot of airplanes that ran out TBOs with no problems!!
Too bad all these graphs are so out of focus...
This FAA A&PIA, 2820549, Army Air Force 1952, Aircraft and And ENGINE school, Keesler Air Force Base, Mississippi. 43---7 ,1952 +. Moved to Japan, 52 ? Air crew WB-29 tail gun 32---7 weapons, Korean War, 2000hr,+ .Story: stationed Army AF in Japan, brown suits, Then in 1955, me in Japan The new created US Air Force Blue suits, with new B-29 -27 fuel injection engines replaced carb engines. Point me to the Aircraft, Gen , mil, it's in my diary. beat that Savvy ? 92, maintain my sons 172 at present. My whole story is boring. Thank you, for reading.
good content, but mediocre presentation