How To Lean The Mixture
Vložit
- čas přidán 17. 03. 2013
- m0a.com I've been asked this question a lot lately... "How/Why do we lean the mixture?" In general aviation aircraft we fly it's crucial that we properly understand how to lean the mixture. After all your performance charts in your Cessna or Piper POH etc are all based on the engine being properly leaned.
I am a very rusty pilot...stopped flying in 1977....came back in 2013....got my bfr done....and learning as much as possible
from your clips and other clips...thanks
OMG thank you for saying specifically that LoP cannot be run in a carb engine! No one else makes that distinction, and for a VERY beginner pilot, those are the kinds of information gems I need, in addition to all the details of LoP and RoP! THANK YOU
Excellent video. As your shirt says "Because a good pilot is always learning."
On your video audio, get a lapel Mic, battery powered. It will cut out back ground noises. Great presentation. Keep up the great work.
What a relief!! I was so caught up trying to wrap my head around mixture procedures and how I am leaning for best performace. The way my CFI taught me, It just didn't make sense!! Following his instruction, I would LEAN AFTER TAXI during RUN UP, wait for a slight RPM drop, and THEN enrichen 3 full rotations... We fly without touching the mixture again, not even having mixture rich during maneuvers. Why would my CFI do this?!
I am a 20 y/o female student flying the coast of California in an old 152. My checkride is December 10th. I bought your program and it is helping me study and understand much more than just reading. I passed my written exam and now I listen to your checkride prep podcasts in the car on the way to work and school. Thanks for your stellar teaching Jason. I wish all CFI's were as awesome as you.
jamaica
+Jamaica Hines how experienced is your instructor!?? that is really wierd!
Maybe you already know the web page "ask a cfi dot com", I've found very useful information there, it's a great source of information even after getting the license/rating.
Jason, great session. Brought it all together for me.
It always helps to define the terms; “EGT” what…………. In your well done video you had a great opportunity to delve quickly into some systems education; what is the EGT gauge, how does it work and what is it telling me and how do I use it in “leaning the engine”. Take the time to explain and even better show the temperature probe inserted into the exhaust system and how it takes a general sample of exhaust gas temperatures and relays that information to the gauge. That would be different from a CHT (Cylinder Head Temperature gauge that monitors individual cylinders.
Often basic explanations are helpful. To get combustion you need two things, a fuel to burn and oxygen. Remove one or the other then the “fire” goes out (the fire in your home or inside the cylinder of your airplane’s engine). The carburetor provides a combustible fuel air mixture. As pilots we start our engine on the ramp. Then we take off and climb. As we climb what is happening to the density of the air as we climb up through the atmosphere? Most of us understand that the air is becoming becomes less dense as we climb, fewer molecules of oxygen (and other gasses) for a given volume. One cubic foot of air at sea level will have fewer oxygen molecules than one cubic foot of air sampled at 10,000’. Now let’s return to our climbing airplane; we are climbing and our carburetor is still mixing in the same amount of gas, we have the mixture knob still full rich, what is happening to the relative mixture of gas to air ratio? Same amount of gas mixed with air that is less dense means the mixture is getting richer. The percentage of gas to air the engine is burning in the cylinders is getting richer; more gas less air/oxygen. If we do nothing with the mixture knob, and keep climbing indefinitely, at some point the gas to air mixture would simply stop burning. As the mixture is getting richer, beyond the “ideal” ratio, the energy extracted out of the gas (engine performance) decreases because not all the gas is being burnt. The unburnt gas is getting passed along with the byproducts of combustion past the spark plug, where it leaves deposits that build up over time, out the exhaust valve into the exhaust system where it is eventually expelled into the atmosphere.
You touched on the difference between carbureted and fuel injected engine which I thought was brilliant. Carburetors produce a combustible fuel air mixture that is fed into an intake manifold verses fuel injected engines deliver the combustible fuel air mixture directly to the cylinder allowing for much more precision. It might have been helpful to highlight a sample Pilot Operating Handbook (POH) as an example of a manufactures recommendation on leaning as you presented your information.
(CFII, ATP, A&P)
This actually made my day! Finally some Accurate info!
I tearned off the auto fuel and air mixture on flight simulator X
to make it seem more real and thise video makes that concept
clearer.THX
please keep up the good work you are doing a great job.
thanks for the vid, helpful for us students, as this isnt a question that ever came UP in flight school. I found that max EGT answer on the net. You gave me a couple new pointers to remember (mix down for taxi, for one). Thanks from a wannabe pilot.
Good work on this subject! Thanks.
I swear to God, I read "A good pilot is always leaning." :)
You spoke mostly about tachometer regulation for rich of peak adjustment but I have a constant speed prop and an EGT on #6 cylinder. What's the best way to lean it?
During cruise LOP settings are much better for the engine than ROP. The CHT is lower, internal cylinder pressures are lower, brake specific fuel consumption is better and there is only a marginal drop in horsepower. Check the data on the Advanced Pilot Seminars and the narratives on sites such as the Pelicans Perch. In addition the engine runs cleaner as well as cooler. Leaning in cruise can be carried out at all altitudes, not just above 3000 ft.
Carbureted engines can also be run quite successfully LOP. i have done so for about 3000 hours with a Continental O-470R
The way I learned it is, ROP is for best power, LOP is for best economy.
No matter WHERE the mixture control is set, you can NOT start an engine fire. Also, not a good idea to max the RPM by leaning and then leave it there. You always enrich a bit for two reasons: 1) It helps keep the engine cool. 2) It reduces the chance of sudden loss of power due to being too lean. [you might consider a disclaimer at the beginning of your videos]
+Jake Jones That's true, thanks for sharing !
and yougot ZERO response!!!!!!!!!!!!! wow thought he would answer you back
Add 1:19 I almost died I swear I always thought the samething like why would I want to touch that lol
me too... lol
Thank you a lot, very professional video
I heard that leaning the mixture in a way you described is not the best idea. It increases the CHT and that's the thing we should avoid (for the sake of engine longevity)
I thought the engine quits only when the red knob is out all the way. This is the reason why I've never worried about shutting down the engine as I leaned the mixture. Never went all the way out, maybe about 75% out. It didn't make much difference. Perhaps a red line around the mixture's metal rod would be handy. Keep up the good work. Thank you.
You would need a moving red line that is tuned to the actual flight conditions, since density altitude will surely affect your mixture setting
@@unclejacksimulations9423 Thanks
Will try this tomorrow...thanks
I have a 172M '74 and have just installed a JPI 830 EDM. I am still trying to figure it out. As my a/c is not fuel injected, should I still attempt to Lean LOP or since I have an EDM, should I attempt LOP? I understand the concepts of leaning, but am a little confused over the difference and what is best for my a/c. thank you
I like how you used flight simulator to demonstrate this.
really helped. now about prob adjustment, you got a video on that?
Could you provide a bit more details on how you lean for taxi? Do you turn the engine on, get it to 1000 rpms, check oil pressure and directly lean? Do you wait a bit while you turn on avionics and then lean? Do you use a different rpm setting to lean, and then set it back to 1000 rpm? So many questions :) Thanks a lot!
I am in Jacksonville Florida and fly the local area and down to south florida...Would it be safe to say that you should lean til the highest RPM and then back off slightly to protect the valves..?
George Baylee That's exactly what he means when he says, "rich of peak". You're finding the peak of the RPM and then moving the mixture lever back towards the richer fuel flow.
CFI question for you...You're doing a run up and one mag check indicates you may have fouling. You go thru procedures and burn off fouling. You're intent that day is to stay in pattern with student. Is that a safe choice (closed traffic work) considering you'll be enriching when applying carb heat (C-172) and cutting power on final with a full rich mixture.
Of course if you leave pattern everything is a little bit different. You'll be leaning out for cruise. Would you be juggling the mixture control the same way when staying in pattern considering you just cleared fouling?
Should the mixture be full rich before turning on carb heat and why?
Jason your videos contain much good information for student and novice pilots. However, Lycoming do not recommend leaning for taxi and it is not because they want to have a debate. It is simply the facts are on their side. If you use the recommended 1000 - 1200 rpm, your mechanic has installed the correct plugs and set the idle mixture properly, it is not necessary to lean for taxi in order to avoid fouled plugs. That rpm band is high enough that temps inside the cylinder are not conducive to fouling. Nonetheless you should lean for smooth operation before a high density altitude take off. On the other hand if you do lean for taxi and then forget to set the mixture for take off you are guaranteed to put the engine into incipient detonation and quite likely outside its certified detonation envelope unless you are at a high DA. That is why Lycoming do not recommend leaning for taxi.
A more likely scenario for lead fouling is returning to the pattern at full rich, perhaps making a glide approach or spot 180, followed by a brief taxi and shutdown. There is no place in that routine where the lead will be scavenged. Hence Lycoming recommend running the engine for 20 seconds at 1800 before shutdown in order to scavenge the lead deposits.
Check out the Lycoming article “to lean or not to lean while you taxi”. And keep the videos coming.
I was taught to lean a knuckles width from the dash when taxiing, then go full rich on run-up and take-off.
If aircraft had 'constant depression' carbs, like the English S.U., or the Zenith-Strombergs, there would be no need for mixture management.The carbs leans themselves with altitude change.
Hey,
Ive always had mixed responses... on a Cessna 152 or 172. When should you lean the mixture? Let’s say taking off from sea level and cruise altitude of 7,000 feet.
Lean mixture as I climb through 3000/4000ft?
Or
Full mixture until cruise altitude, and then lean for cruise
What would you do/recommend?
my mans got the beanie baby on the desk, legend
Some answers: The 3 turn rule is to get the mixture nob 1/2 inch in. However, the proper setting on a carbeurated engine is find max EGT by leaning to max for smooth engine and monitor EGT 5 sec, Then increase mixture to drop temp 25 deg. for max performance [fuel economy], Or, 50 deg for max power. Check it during flight as temp and barometric pressure are always changing!! Also, an engine CAN QUIT from fowling being TOO RICH. Be Safe, and Happy Flying :)
Can you define "high altitude"? The airport I fly out of is at 3,449'. It often has a DA of 6,000' +. Would you consider one or both of those "high altitude"?
Concerning leaning the mixture at or above 3K' . I was always taught to lean until the engine "started" to lose RPM and then to bring richness back until it smoothed out. Is this a correct method or is the method you just showed by leaning until RPM climbed and just before it started to drop the best way? I know it sounds kind of dumb but this is important enough for me to understand that I don't mind sounding dumb. By the way, I really love the way you teach and explain all aspects of piloting. I live in So. Calif and I know you're on the east coast. I sure do wish you were out here. Your method of teaching and explaining is tops in my book, bar none. Thanks in advance for your help.
There is no such thing as stupid question, you state a good point here pal
The best way is to use your EGT if you have one!
The best way is with an engine monitor that has an EGT for each cylinder. They will track EGT and automatically tell you when the first or last cylinder peaks depending on your setting.
Do you have any suggestions for running lean of peak flying a turbo? I have been flying with a buddy of mine that fly's a Cessna 401/402 turbo charged fuel injected continental engines. The plane does not have an engine monitor. I have looked all over the web for fuel management techniques - no success. I would love to hear you thoughts on this issue.
Not much you can do if you have an auto-compensating fuel system and no instrumentation.
I did a mock checkride with an different instructor, a CFII. I have been leaning mix for taxing and got away with leaning right just after landing and flaps up then lean. Bad practice? When I did this the CFII said that was a FAIL! Was it because I was was still on the runway? He said I needed to stop before adjusting the mix. So get off runway over threshold then stop and lean mix?... I need and want the right answer
How about adjusting the mixture on an aircraft with a constant speed prop?
Hi, when you talk about leaning the mix during taxiing, A) do you mean an airfield over 3000 ft?
B) if it is below 3000 ft at what RPM regimen would the mixture have to
be regulated during the taxing?
In my 172N after oil temp gets about 180deg at 1000rpm I lean for peak. I found out by the time I reach run-up area I have no problems with mag drops. My airfield is well below 3000ft. If I stay in pattern I leave it that way.
Missed opportunity to temporarily change your motto to: "A Good Pilot is Always Leaning"
Ha! That would've been funny! Thanks for watching, Christi!
Ok the video makes a good point but what about vp prop aircraft will this method still work?
Set the pitch you want and then lean from there.
mikeallenbrown1 it's always about the money, and the fact that most GA aircraft that most people fly were built way back in the day.
Awesome
Figured out the solution for problematic C-172 with mag drop due to fouling if you stay in pattern.
Good question. There have been automatic mixtures on airplanes since 1930s or so. Also eaven the cheapest ultralight planes have automatic mixtures. Many modern GA planes have FADEC controls these days. Why americans still use technology from the 50s? Why new Piper Archer still has a carb engine? Maybe they are simple and reliable. I like old engines, but don't really understand how they can be legal to sell in new planes these days :D
Why when 3,000 feet leaning the mixture will increase the engine performance ? and also if your airport is on 4000 feet how much mixture you will consider to lean on taxiing ?
Answer to your first question: Because if you leave the mixture in full rich, you won't only be wasting unburned fuel out the exhaust pipe, you'll ALSO be wasting some of the heat energy of the fuel you DO burn by heating up the unburned fuel to the engine's temperature -- and THAT means less energy available to turn the prop!
my understanding was that I mix to maximize the EGT... is that too simplistic?
a good everyone are always learning:)
Basically how I was taught in our 150s and 172s was, half inch during taxi and above 3000 ft. Then for every 500+ feet after, it’s 2 twist
should you lean during a climb, say you cross 3K, but are climbing to 5,500? do you wait until the climb is over, or start at 3,000?
Just remember that your engine mixture is becoming richer with altitude. 3000' is a starting point and yes, you can lean the mixture as you climb through 3000' but you can wait until top of climb if you're only going to 5,500'. It takes practice and can be distracting so don't forget to fly first and scan for traffic as you practice leaning the mixture during climb. I personally start at 3,000'. It saves the plugs and fuel burn during climb.
Could you explain QNH vs Altimeter: why QNH is in Hectopascals and have numbers like 1008 vs Altimeter numbers like 30.14.
Hello! They are different forms of measurements. Just like 0 degrees Celsius is 32 degrees Fahrenheit. It is the same temperature, just measured differently. It is the same with the altimeter settings. Some countries use inches of Mercury and some use Hectopascals. I hope this helps! Thanks for watching!
@@MzeroAFlightTraining Actually, this really helped! Thank you.
Thanks. You always make things more easier then my instructor. Maybe I should pay your 250.00 hr?..LOL..Thanks
HiEven though I am a PPL, to lean mixture is always a problem even though I have been shown how to do it numerous times.By the way nice T-shirt. How do I get one?
brad well we don’t have that shirt available anymore, but our new ones are updated and just as awesome! m0a.com/store/product-category/gear/
Did this video help you understand leaning?
what should your mixture be at if you are climbing at full power from 8000 to 9000 feet
Reference your aircraft's POH, it will have measures for best fuel econ, best airspeed and at what conditions. With proper fuel leaning and prop pitch you can get those impressive fuel burn rates and airspeeds at those given altitudes or very close to it based again on atmospheric conditions.
FINALLY! Someone that actually AGREES Lean of Peak is BAD! All the old school pilots are POPPING engines left right and centre! My flight school was eating engines like a champ.... I argued that lean of peak is HORRIBLE for any engine unless you can monitor each cylinder. Now, from my understanding, after years and years and years, Cessna / Lycoming came out with a notice of how to properly lean their engines now.
Go Figure!
Chad
I get:
100% mixture at 2700 feet
74.9% mixture at 2750 feet
50.1% mixture at 8000 feet
44.3% mixture at 10000 feet
36.2% mixture at 13000 feet
33.7% mixture at 14000 feet
ask yourself this question. have you even looked at the POH? cause it tells you all of this in there and at what altitudes you need to adjust.
Why do planes STILL have mixture controls?? ... electronic fuel control would take care of this, wouldn't it?
Your concept of leaning on taxing may lead to an accident if the mixture is not full rich on applying takeoff power after run up checks are done. The PIC would have to very vigilant on his checklist before takeoff if he doesn't the engine will not develope full power and cause excessive EGT and high CHT"s as well.
Try taxing a big lycoming or continental, if you leave it rich it will foul the plugs in no time. POH recommend that
It is strongly recommended to lean during ground ops. It is also good to lean to max rpm during ignition pre flight. After the run up place the mixture full rich complete the checklist and take off.. Not brain surgery. It is incumbent on the pilot to be coherent enough to make sure all the knobs are in during takeoff.
If you're leaned out as far as possible for taxiing, there's no way to leave @ full power accidentally, the engine will shut down and not produce power that lean.. A final pre flight check at the hold short line is also a must checking (at least) mixture, controls and gauges before departure..
Rick Cahill j
McPilot g
I came here because of playing a game
Why to have full rich mixture at takeoff if it makes the airplane perform worse? And why 3000 ft?
Full rich at takeoff DOES NOT make the performance worse UNLESS you're above 3000 ft. density altitude on takeoff -- but if you are, then it DOES, and THAT is when you SHOULD NOT use full rich on takeoff but lean for best power!
So ... rich of peak once you leaning from rich to peak performance do you or do you not turn it back in 3 turns? Also if you do not have the option to turn and you have to push? Now what? Also when you say 3 turns does that mean full turns? Boy there are a lot of open questions. Rich of peak means what? You get to peak performance from a rich condition? Sorry but I never heard the term rich of peak.
Video start 1:39
i`m sorry to say, it looks like you just got out of bed!!! how can we trust.... hmmm. just kidding bro. GREAT VID. i even lean my Harley on long straight shots..(live in Nevada we got roads that go for 200 miles in a line) external mixture screws are the best, just wish i could re-jet it in motion...
Wait so you'll pay for it?
I just want to fly...
Good video... But sound...
Sorry but are you saying that has made all the way to Commercial and beyond WITHOUT knowing to lean the mixtrure. Better send your pal student to Aeroclub Canelones that we will teach them. I like to call o"ld school" as "primeval school". You have to learn how to care your engine from the first start up. Cheers.
This ain't the kinda lean video I came to watch, misleading title
don't people listen to their instructors
I stopped listening after engine fire possible while taxing full rich...BS
Basically decent videos. A bit repetitive. Get to the point.
Take what this guy is saying with a grain of salt. Not accurate for all engines.