Mixture leaning strategies/thoughts

Tristar said:
Jesse,

I must have missunderstood your story. I thought you flew it down to the last 30 minutes of fuel. What were you flying to have 55 gallons "still" in the tanks?
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Two different stories. One was about landing with too much fuel. The other was a reason to always fly like the engine is going to quit--because it might. It was a Beech Sierra and the throttle failed. I glided back to the airport to land.

Tristar said:
Boy you really like to pick on me about my centerline take offs and landings. I'm short...I'm working on it!
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I wasn't picking on you about it. It's a problem for a lot of pilots. Most just ignore it and say it doesn't matter the runway is wide. It's something I always bring up. It's easy to fix and is the first step in flying with more precision. It's just a matter of noticing, and fixing all the little things.

Tristar said:
Here's a question for ya which I hope doesn't take us off topic. When ATC says "fly runway heading" does it mean to track runway heading or if the runway is runway 36 you fly straight north on the DG/compass? I always thought it was tracking runway heading so you don't over fly another airplane but a CFI once told me no that it was fly that runways magnetic heading despite the wind because other aircraft will also drift with the wind. I don't believe I believe this but during climb out, I didnt feel like arguing with an ATP instructor....although I found it slightly funny that a few seconds later ATC told us to scoot over which I would have been correct but arguably only when ATC instructed me to do so.
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The ATP instructor is correct. Fly the magnetic heading. I'm assuming you guys were flying IFR and had filed a flight plan. This was probably part of your takeoff clearance. There is no way in actual instrument conditions to follow the ground track off the runway. Fly runway heading would mean fly the magnetic heading of the runway. All other airplanes will drift with you.

I suspect it's possible a controller might say this sometimes and expect you to have a straight ground track off the runway and later tell you to correct when they notice you drifting.

If there was a situation where I noticed opposing traffic that would justify me to fly straight off the runway I would ask the controller for confirmation. For example if I was taking off at an airport with parallel runways I'd be paying a lot of attention to this and most likely ask for confirmation if the winds were going to carry me over the other one.
 
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Tristar said:
I don't believe I've ever heard of levers on an airplane for leaning. What types?
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Darn near everything except Cessna.

Actually, some very old Mooneys and Pipers also had knobs. But, for the most part, the planes I've flown have followed the Cessna=knobs and everyone else=levers rule. The Cub and Super Cub have a mixture knob though.

and two (which I'm hoping to understand) I'm afraid of leaning too much and the engine failing on take off/climbout. Is that just a paranoya or a justifiable concern?
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It's not completely clear if you meant leaning for takeoff or leaning for taxi. The trick to leaning for taxi is to lean it so much that if you were to forget to enrichen the mixture before takeoff the engine will fail as soon as you add power. If you want to lean for takeoff, do a full-power runup and do your leaning at full power standing still, then you shouldn't have any problems on takeoff.

I also put in full rich every time I land. I wonder if that would be a problem of actualy drowning the engine in some areas such as in the mountains.
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It could, but I'll let the experienced mountain guys chime in on this.
 
Tristar said:
Here's a question for ya which I hope doesn't take us off topic. When ATC says "fly runway heading" does it mean to track runway heading or if the runway is runway 36 you fly straight north on the DG/compass? I always thought it was tracking runway heading so you don't over fly another airplane but a CFI once told me no that it was fly that runways magnetic heading despite the wind because other aircraft will also drift with the wind. I don't believe I believe this but during climb out, I didnt feel like arguing with an ATP instructor....although I found it slightly funny that a few seconds later ATC told us to scoot over which I would have been correct but arguably only when ATC instructed me to do so.
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CFI's right. Think about it this way... When you take off into a 200-foot overcast and ATC says to "fly runway heading," What will you do? No choice, really. You keep the airplane pointed the way it was pointed on the runway. The key is the word "heading". If they wanted you to crab into the wind and maintain the extended centerline, I think they'd use a word like "course" or maybe "track." However, they don't do that anyway.
 
AirBaker said:
Isn't there a table for this in the Cessna POH??
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yea, I think they list a 172P as burning 7 or 7.5 gph in cruise. ive never been able to get less than 8.5 So I dont pay attention to the charts, and use my (and others) experience.
 
Jesse,

No offense but then why are you getting on to me about tracking centerline if I'm just following the magnetic heading? Is this a VFR/IFR difference? Because then I wouldn't be doing what ATC says because I would be compensating for the wind.

My CFI during private used to always tell me to look behind me and that I wasn't on centerline despite me still on my heading. So its hard to grasp knowing where the line is to do which; track or fly heading.
 
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flyingcheesehead said:
It could, but I'll let the experienced mountain guys chime in on this.
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A few miles out, momentarily go to full power... Set your target EGTs at 1250-1300. Don't touch the mixture after that. If you need to go around, you're already on target.



tonycondon said:
yea, I think they list a 172P as burning 7 or 7.5 gph in cruise. ive never been able to get less than 8.5 So I dont pay attention to the charts, and use my (and others) experience.
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I haven't flown a 172 in years now... but I remember the POH being within .4 gallon of our planned flight. SO I can't tell you what we did, I just remember it being close. :)
 
Tristar said:
Jesse,

No offense but then why are you getting on to me about tracking centerline if I'm just following the magnetic heading? Is this a VFR/IFR difference? Because then I wouldn't be doing what ATC says because I would be compensating for the wind.
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If you aren't on a IFR clearance and a controller did not tell you specifically to fly runway heading (very rare they do that) it is best to stay lined up with the runway until you turn on course. This keeps you in flow with the standard traffic pattern. It also makes you more aware of your airplane position over the ground and is another step in better airplane control. If you takeoff from an airport with paralleling runways you do not want to drift over to the other one. Stuff like this will become important for your commercial ride.

A little more right rudder and the problem would go away. When I've flown with you we always drifted to the left. Once you get used to staying coordinated during climb out and staying on the runway centerline it will feel very odd to you when you are not.
 
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Tristar said:
...constant turns in a certain direction can even starve the airplane...
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Don't be spreading old wives' tales! (unless you're an old wife ;))...your good rudder coordination means this won't happen.Fly safe! David
 
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I have 4 CHT and 4 EGT probes in my Cherokee. I lean as much as I can and still keep the CHT temps under 400. That's my upper limit. So if I am leaning at sea level and keeping it under 400, , then I'm leaning at sea level. Sometimes that's a shallowed out climb, sometimes it's a mixture increase, and sometimes it's both. If I am below 400 on the CHTs I'm under 1400 on the EGTs. When I get up into cruise I usually end up about 385 on the hottest cylinder, and about 1395 on the EGTs
 
Tristar said:
No offense but then why are you getting on to me about tracking centerline if I'm just following the magnetic heading? Is this a VFR/IFR difference? Because then I wouldn't be doing what ATC says because I would be compensating for the wind.

My CFI during private used to always tell me to look behind me and that I wasn't on centerline despite me still on my heading. So its hard to grasp knowing where the line is to do which; track or fly heading.
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Tris,

I think Jesse is talking pattern work at uncontrolled fields. If the tower tells you to fly runway heading, they mean runway heading and not centerline.

When you're flying patterns at an uncontrolled field and thus nobody is telling you to fly runway heading, go ahead and crab it. That makes it easier for other folks to see you at a glance. I'm guessing your primary CFI was having you do that as a way to practice ground reference as well.

So, when you fly a pattern, you're looking for a rectangular ground track, not four headings. When the tower tells you to fly runway heading, you just point that way and let the wind do what it will to you.
 
Tristar said:
I'll show you the guage this weekend and we can correct it. I thought it was fuel flow.
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Actually in many fuel injected airplanes the "fuel flow" gauge is a pressure gauge connected to the fuel distributor and reading the pressure in the injector lines. The theory is that since the flow/pressure relationship of the injectors is consistent, the scale on the pressure gauge can be marked with flow rates and be reasonably accurate. One downside of this is that if an injector becomes fouled the flow to that injector's cylinders will be reduced from what it would normally be for the same indication on the gauge.

Tristan, the "religion" of leaning has about as many variations as Christianity. And like the church, most of them are based on faith rather than actual scientific priniciple or emperical testing. Part of the reason for that is that most engines are pretty robust WRT mixture settings when operating at typical cruise power settings so almost any method will produce useable (but not necessarily optimal) results. At takeoff power OTOH, mixture mismanagement can cause serious damage to almost any aircraft engine, with the severity potential generally increasing with engine size and even worse with turbocharging. You can literally destroy a big bore highly turbocharged engine in seconds running at full power (and these engines will make full power at pretty high altitudes) with improper leaning, but I think you'd be hard pressed to have much if any impact on an O-320 running any mixture when flying above about 5000 ft DA and probably even lower.

John Deakin has written some pretty good articles on mixture management and engine operation in general. I highly recommend giving them a thorough read.


Where Should I Run My Engine? - Part I
Where Should I Run My Engine? (Climb)
Where Should I Run My Engine? (Cruise)
Where Should I Run My Engine? (Descent)
http://www.warmkessel.com/jr/flying/td/jd/66.jsp
 
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jesse said:
Two different stories. One was about landing with too much fuel. The other was a reason to always fly like the engine is going to quit--because it might. It was a Beech Sierra and the throttle failed. I glided back to the airport to land.


I wasn't picking on you about it. It's a problem for a lot of pilots. Most just ignore it and say it doesn't matter the runway is wide. It's something I always bring up. It's easy to fix and is the first step in flying with more precision. It's just a matter of noticing, and fixing all the little things.



The ATP instructor is correct. Fly the magnetic heading. I'm assuming you guys were flying IFR and had filed a flight plan. This was probably part of your takeoff clearance. There is no way in actual instrument conditions to follow the ground track off the runway. Fly runway heading would mean fly the magnetic heading of the runway. All other airplanes will drift with you.

I suspect it's possible a controller might say this sometimes and expect you to have a straight ground track off the runway and later tell you to correct when they notice you drifting.

If there was a situation where I noticed opposing traffic that would justify me to fly straight off the runway I would ask the controller for confirmation. For example if I was taking off at an airport with parallel runways I'd be paying a lot of attention to this and most likely ask for confirmation if the winds were going to carry me over the other one.
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This is one of the (many) situations that defy a logical analysis. AFaIK, taking off under VFR you are supposed to maintain the extended centerline, and this is pretty important when operating from parallel runways. But under IFR you are supposed to fly the runway heading, letting the wind drift you off the centerline. While this might seem logical at first, I think it's nonsense under most circumstances. First, consider a takeoff from a single runway airport in IMC. Separation is provided by radar vectors, altitude assignments, and time. I could be wrong, but I don't think you'll ever be cleared for takeoff from a class D airport under IFR in IMC when there is traffic departing a parallel runway so there shouldn't be any conflict there.

I believe the real reason for the difference betewen normal IFR and VFR departure paths is related to the fact that in IMC there was usually no way to maintain the runway centerline, certainly not visually so the mantra was to maintain heading.
 
lancefisher said:
This is one of the (many) situations that defy a logical analysis. AFaIK, taking off under VFR you are supposed to maintain the extended centerline, and this is pretty important when operating from parallel runways. But under IFR you are supposed to fly the runway heading, letting the wind drift you off the centerline. While this might seem logical at first, I think it's nonsense under most circumstances. First, consider a takeoff from a single runway airport in IMC. Separation is provided by radar vectors, altitude assignments, and time. I could be wrong, but I don't think you'll ever be cleared for takeoff from a class D airport under IFR in IMC when there is traffic departing a parallel runway so there shouldn't be any conflict there.

I believe the real reason for the difference betewen normal IFR and VFR departure paths is related to the fact that in IMC there was usually no way to maintain the runway centerline, certainly not visually so the mantra was to maintain heading.
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Yeah. When I was writing that I was trying to think of what I'd do. In VFR I always maintain the extended centerline. I also can think of very few times, if any, that I have been told "fly runway heading" VFR. Every takeoff I can think of has been turn on course after takeoff. It's possible that they might want to you to fly the runway for traffic and I'm sure they'd want you to maintain the centerline versus the heading.

So it kind of comes down to "it depends".

As far as the mixture thing--that is well said.
 
flyingcheesehead said:
Actually, some very old Mooneys and Pipers also had knobs.
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Mooneys have had both. They had knobs, then the original 201's had quadrants, then they went back to knobs (our '78 has knobs). I don't know about the newest ones, but I'd bet they have knobs. More passenger space.
 
Tristar said:
So after all of my learning up to this point is said and done, I was curious if you would share your thoughts and processes as to your leaning procedures.
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I right now fly three airplanes, two fixed prop 4 bangers (172 and Archer III), and a big six 182 (2001 model with derated IO-540).

172 and Archer:
  • AGRESSIVE ground leaning, engine won't turn much more than 1200-1300rpm before it starves.
  • If DA <3000, full rich for mag check and takeoff provided mag check is clean.
  • At 3000msl, if oil temp well in the green, lean for best power. Easy to do in a fixed prop, just lean for peak RPM. Maintain this mixture for balance of climb, maintain watch on temps.
  • Once at level cruise, set intended power setting, then use the "feet on floor" lean until rough, enrichen until smooth. Never had an issue, and get good speed and fuel burn.
  • Maintain cruise mixture during decent, go full rich passing thru 3000 on the way down.
182:
  • AGRESSIVE ground leaning, engine won't turn much more than 1200-1300rpm before it starves.
  • If DA <3000, full rich for mag check and takeoff provided mag check is clean.
  • At 1500-2000agl, pull throttle back to the top of the green arc (23").
  • At 3000msl, if CHT and oil temp well in the green, lean to 15g/h and maintain watch on temps.
  • At 4000msl, if CHT and oil temp well in the green, trail cowl flaps half closed and maintain watch on temps.
  • Maintain 23" by bumping throttle in as necessary, maintain 15g/h, and watch temps.
  • Once the throttle is full in (6-7k), start leaning a little as MP starts to fall off.
  • Level in cruise, usually full throttle at 9-10kmsl, prop back to what you want, then lean peak and back off 50. Suprisingly, lean until rough and rich to smooth gets you to about the same place, but I get nervious with that big six, and do it on the EGT. Cowl flaps closed.
I'm sure this will get picked apart. :yes:
 
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I dont see anything too scary in there Bill.


Get your Mooney yet?
 
tonycondon said:
Get your Mooney yet?
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Latest guestimate, week of March 19-24. If it happends, I then have to pound out 10 dual in a week if I want to get to the glide-a-thon.
 
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Bill Jennings said:
Latest guestimate, week of March 19-24. If it happends, I then have to pound out 10 dual in a week if I want to get to the glide-a-thon.
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well heck that'll be easy. if you cant pull it off though, bring your CFI, he'll have fun too!
 
jesse said:
You can't stop people from being idiots. He is probably leaning way out until he gets best power and rolling with it. I lean until I hit best power and enrichen generously from there. I also watch what the EGT is telling me. Of course it's only one cylinder but it's better than nothing. Sometimes it's almost no difference but on real hot days it matters a LOT.
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Unless you have a four probe CHT/EGT engine monitor, this is very dangerous. You are not operating the engine properly and as others have said this could cause severe damage.
 
lancefisher said:
This is one of the (many) situations that defy a logical analysis. AFaIK, taking off under VFR you are supposed to maintain the extended centerline, and this is pretty important when operating from parallel runways.
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Lance,

So you're saying that at a towered airport, I should still try to track the centerline?

So, I'm sitting on runway 32 at MSN. Cleared for takeoff, fly runway heading. I'm IFR, so I point the DG at 320 (or whatever the actual heading is) and go.

Now, same situation but I'm VFR. Does the same tower controller telling me the same thing now mean something different?

OK, same situation only the weather is going down. 4 miles vis, 1500' ceiling. I'm VFR, staying in the pattern but everyone else around me is IFR. Same controller, telling me to maintain runway heading... Should I be doing something different than everyone else?

What I'm saying is, I think at a tower-controlled field, runway heading is just that... *heading*. Not ground track. If they don't tell you to fly runway heading and you're staying in the pattern, sure you can do the ground track. Or, if they don't assign runway heading. But, I'm almost positive they're expecting ground track.

Time to interview a tower controller. :yes:
 
Bill Jennings said:
  • Level in cruise, usually full throttle at 9-10kmsl, prop back to what you want, then lean peak and back off 50. Suprisingly, lean until rough and rich to smooth gets you to about the same place, but I get nervious with that big six, and do it on the EGT. Cowl flaps closed.
I'm sure this will get picked apart. :yes:
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It is a non turbo right? I'm not picking it apart. :)

Above 9-10k you can pretty much park that mixture just about anywhere and not hurt it. The engine wont be making enough power to cause any serious harm.
 
AirBaker said:
It is a non turbo right? I'm not picking it apart. :)

Above 9-10k you can pretty much park that mixture just about anywhere and not hurt it. The engine wont be making enough power to cause any serious harm.
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Non-turbo, and yeah, once it's firewalled and the MP starts dropping, you should be ok.
 
Tristar said:
Anthony,

Could you explain please?
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Leaning below 5,000 ft DA is not recommended by Lycoming which is the type of engine I have in my Grumman Tiger. If you can monitor CHT's in climb and keep them below 400F, then I can see leaning sometimes below 5,000 ft DA if you need maximum performance. I've done it, but I have an engine monitor that lets me see all 4 CHT's (cylinder head temps). These are more important than EGT's (exhaust gas temp) because CHT's above 400F can damage the cylinder. In the summer at high DA's like when I lived in Colorado, you can get very high CHT's in the climbout. Once I was approaching 400F CHT's on my hottest cylinder, I'd always go full rich in the climb, then lean out in cruise when there was better airflow over the cylinders. My point to all this is that you can damage your engine by leaning below 5,000 Ft DA if you don't watch the CHT's and if you only have a single cylinder engine probe, the other cylinders can be cooking even if that one cylinder is not.
 
tonycondon said:
Ill see Rick, our buddy from DSM, on Saturday at the Soaring Banquet. Ill ask him if he wants to be on a Pilotcast. Im sure the answer will be yes.
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Already asked and answered... Problem is, he's TRACON, not tower. I have an idea, though... :D
 
oh i figured that the guys there could work all positions.
 
Anthony said:
Leaning below 5,000 ft DA is not recommended by Lycoming which is the type of engine I have in my Grumman Tiger. If you can monitor CHT's in climb and keep them below 400F, then I can see leaning sometimes below 5,000 ft DA if you need maximum performance. I've done it, but I have an engine monitor that lets me see all 4 CHT's (cylinder head temps). These are more important than EGT's (exhaust gas temp) because CHT's above 400F can damage the cylinder. In the summer at high DA's like when I lived in Colorado, you can get very high CHT's in the climbout. Once I was approaching 400F CHT's on my hottest cylinder, I'd always go full rich in the climb, then lean out in cruise when there was better airflow over the cylinders. My point to all this is that you can damage your engine by leaning below 5,000 Ft DA if you don't watch the CHT's and if you only have a single cylinder engine probe, the other cylinders can be cooking even if that one cylinder is not.
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Like I said. It takes a little common sense. The leaning is part of my runup IT MUST BE DONE AT FULL POWER. If you leaned at runup RPM or anything less than full power you could cause major problems. I also said that it is quite often little to nothing whereas sometimes with high density it becomes important. I have flown planes with probes on every cylinder and there was no threat. This time of year it is nothing. In the summer when it gets hot it might be a little. Get to a higher elevation airport with a less than ideal runway and it is hot and it becomes a fair amount. The idea is for it to be procedure for me so I don't forget. With high density you will not be developing full power no matter what you do.

Obviously Lycoming is not going to tell people to do it--because they are not going to want to be responsible for those that have no common sense crank the mixture back to best power and takeoff without a thought every time.
 
I'm sure he'll tell you the same thing the tower/tracon personnnel here told me. "Heading" means heading. Whether it's explicit when given in specific degrees, or implicit when given in runway heading, ATC expects you to hold assigned heading. Heading as displayed on your DG/HSI. It's very unprofessional to create a new definition for standard phraseology and could compromise safety if you do something a controller doesn't expect you to do. If you maintained runway centerline on departure in any kind of wind condition your heading would change as you climbed, as winds change with altitude in most instances. That would raise some eyebrows in the dark room with the green screen, regardless of meteorological conditions.

One should refer to the ATC handbook

http://www.faa.gov/airports_airtraffic/air_traffic/publications/atpubs/ATC/index.htm

and the Pilot/Controller Glossary

http://www.faa.gov/airports_airtraffic/air_traffic/publications/atpubs/pcg/

if they have doubts about standard phraseology.

RUNWAY HEADING- The magnetic direction that corresponds with the runway centerline extended, not the painted runway number. When cleared to "fly or maintain runway heading," pilots are expected to fly or maintain the heading that corresponds with the extended centerline of the departure runway. Drift correction shall not be applied; e.g., Runway 4, actual magnetic heading of the runway centerline 044, fly 044.

[emphasis mine]

Maybe up north they fly differently....B)

flyingcheesehead said:
...



Time to interview a tower controller. :yes:
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Steve said:
Maybe up north they fly differently....B)
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My view is.. If they tell you fly a heading, fly that heading. But I can think of very few times VFR that a controller has told me to fly runway heading. If they don't say that I'm going to hold runway centerline. Both airports I fly out of up here have paralleling runways and they get a little unhappy if you drift into another airplane.
 
You're discounting the fact that the other airplane is in the same airmass as you. ATC recognizes that little fact and directs accordingly. Best to negotiate any other desired outcomes.

Here the two main airports have 3 parallel runways, albeit one is 7 miles from the other two. It is rare clearance delivery or the tower doesn't include the phrase "maintain runway heading" in departure instructions. And if you're getting flight following often they want you to maintain it until handed off to Departure, despite your route of flight, particularly if there are other aircraft in the local airspace. I've been "the other aircraft" frequently and they'll direct me around the approach and departure paths to remain clear of arrivals and departures while enroute to/from my home base.

jesse said:
My view is.. If they tell you fly a heading, fly that heading. But I can think of very few times VFR that a controller has told me to fly runway heading. If they don't say that I'm going to hold runway centerline. Both airports I fly out of up here have paralleling runways and they get a little unhappy if you drift into another airplane.
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Steve said:
You're discounting the fact that the other airplane is in the same airmass as you. ATC recognizes that little fact and directs accordingly. Best to negotiate any other desired outcomes.
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No I'm not. I don't recall I've ever had a controller tell me fly runway heading while VFR. I'm trying to recall their exact instructions but usually if there is conflicting traffic on the parallel runway they will warn you and make it very clear not to drift over. Lance would probably know their exact warning better then me.

If I am departing VFR and they do not tell me to fly a heading or if I am flying a pattern I will maintain runway centerline. Departing isn't as big of a deal as a pattern. If you don't maintain the runway centerline doing patterns it's no good. If you don't maintain centerline doing patterns at an airport with a parallel you are asking for trouble.

I already said above. If the controller specifically tells you to fly a heading I would do that. If they do not tell me to fly a heading I will maintain centerline until I turn on course. If I felt there would be a traffic conflict I would say so to the controller.
 
I wanted to amplify some on Lance's remarks, but the links he provided don't work for me. Here's another set of links to Deakin's articles. Pretty much everything that's know about leaning, both rich and lean of peak, is in here. Something for everybody:

Where Should I Run My Engine? - Part I
Where Should I Run My Engine? (Climb)
Where Should I Run My Engine? (Cruise)
Where Should I Run My Engine? (Descent)

Tristan,

At any power setting 65% or below I'll lean to 80°F rich of peak EGT. That's where the engine makes the most power for the throttle setting. If I'm at 65% I'm usually up high so I want all the horses I can muster. Down lower I'm usually in what Deakin describes as "Go Fast" mode - high power settings LOP. That's probably not where you want to start, but you did ask what our practices were.

Jesse,

Check out what Deakin has to say about the "Target EGT" technique in #1 & #2. Once you learn what your EGT is supposed to be on takeoff you can set it during the roll and do away with those full-power runups (hard on the prop). You don't need a fancy monitor to do this, a single EGT gauge works fine. The technique works everywhere - I've used it for takeoffs at density altitudes from sea level to 9,000'.

Regards,
Joe
 
Joe B said:
Jesse,

Check out what Deakin has to say about the "Target EGT" technique in #1 & #2. Once you learn what your EGT is supposed to be on takeoff you can set it during the roll and do away with those full-power runups (hard on the prop). You don't need a fancy monitor to do this, a single EGT gauge works fine. The technique works everywhere - I've used it for takeoffs at density altitudes from sea level to 9,000'.

Regards,
Joe
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I often do it on takeoff but I'll take a look at what he has to say. Doing it with the EGT would be much easier.
 
johndeakin said:
With all aircraft engines, use full available rated takeoff horsepower for all takeoffs. I cannot think of a single exception. You are usually not being kind to your engine when you use less, and you may very well be mistreating it when you do so. I see warbird operators using a lot less power all the time, and I think they're wrong. You can tell 'em, but you can't tell 'em much. If the engine manufacturer has published data for an alternate power setting for takeoff, that's fine, too. Otherwise, stick to the full rated power. That means full throttle (for normally aspirated engines), full redline RPM, and mixture full rich at sea level, or leaned appropriately for altitude.

While I'm grumbling, get your tachometer checked, too, many are not accurate. You want full redline RPM for takeoff, no more, and no less. It's important.

Somewhere in pilot training, lip service may be paid to higher elevation takeoffs, and leaning for those takeoffs may be mentioned casually by a newbie CFI who has never been to anything but a sea level airport. It usually takes attendance at a mountain-flying course to get the training for that, unless the pilot just happens to take his training at a high elevation in the first place. I learned to fly in Florida, so my first high-elevation takeoff was a harsh lesson.

Somewhere above about 3,000 to 5,000 feet, leaning for takeoff starts to take on significant importance, and even more so with shorter runways, hot days, deep canyons, poor runways, long grass, and other performance-inhibiting conditions. Above those altitudes, the full-rich mixture setting is much too rich, and will cause a major loss of available power. Since the altitude has already reduced your power (less air), you're not making as much heat, and you don't need the excess fuel for cooling.

The books are full of various techniques for this, but I find the simplest and most effective is just add full throttle, full RPM, then grab the mixture knob and move it aggressively from full rich to whatever feels like "more power" on the takeoff roll. You can't hurt the engine with momentary mixture settings like this on normally aspirated engines! Saw that mixture knob back and forth, and feel the power change in the seat of your pants! At some point as you pull the mixture out from full rich, you'll feel the power first increase, then for a large part of the movement you'll feel no power change at all, because the "best power" mixture setting is very flat in that area. (In other words, "best power" occurs over a fairly wide range of rich settings, but not at full rich.) Go ahead, pull it a bit too far, and you'll feel the power drop off from being not rich enough. Push it back in to the point where you first felt the best power, and forget it. It's quick, simple, and very effective, and pinpoint accuracy is not necessary.
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Like I said. It takes a little common sense.
 
AirBaker said:
Don't forget the Mixture FULL rich @ sea level. :)
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Don't forget the:
or leaned appropriately for altitude.

Unless it's standard temperature at sea level. You're not at sea level.
 
AirBaker said:
You're at what... 1000' MSL out there? Don't bother.
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So the best reason you can come up with now is "don't bother". I like to establish procedure. Forget something at the wrong time someday and it's game over.

Set it for what you need. Sealevel at Standard Temp is most likely full rich IF your mechanic has your airplane setup properly. Most airplanes probably aren't. Use your head.
 
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