Mixture leaning strategies/thoughts

My best? Was this a contest?? :) Go ahead and adjust the mixture if you feel that's going to help.
 
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.
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Right on, Jesse... But I think you're confusing some people. The question was what to do when tower tells you to maintain runway heading. You may not get it VFR much, but I get it VFR a lot (along with turns to other headings).

So, IF tower tells you runway heading... Keep that DG stuck and don't bother looking over your shoulder at the runway.
 
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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I assume that you are talking about leaning during a climb. There's nothing wrong with leaning most engines at any altitude when running 65% or less as is typical of cruise power settings.
 
I could swear that the links were correct when I posted them and I have no clue where the bogus ones came from. I replaced the broken links with a copy of the ones you posted.

Joe B said:
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.
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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.

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.
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Departing VFR at my towered home base I also rarely hear anything about a heading, and as I said, in that case I believe the correct action is to maintain the centerline and to definitely avoid getting near the centerline of the parallel runway. But if one is given a heading be it "fly runway heading" or "fly heading 170" the correct action is to do what your told (fly heading not the centerline) although you shouldn't normally make any turns until reaching 400 AGL.
 
lancefisher said:
I assume that you are talking about leaning during a climb. There's nothing wrong with leaning most engines at any altitude when running 65% or less as is typical of cruise power settings.
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The R182 I fly fouls very easily so any time at idle, its backed out considerably. But, at take off its full rich. As I climb past about a 1000 AGL, I'll back down to 23" and start to back out mixture to a ballpark range on the EGT. Upon returning to land, it's back to full rich.

I'd never lean for takeoff unless DA was above 3000. The book doesn't call for it and since I'd be judged by the book...

I figure I can lean upon departure and be just fine. That falls within the book. I had been getting the impression many are always leaning prior to takeoff even at sea level.
 
KennyFlys said:
The book doesn't call for it and since I'd be judged by the book...

I figure I can lean upon departure and be just fine. That falls within the book. I had been getting the impression many are always leaning prior to takeoff even at sea level.
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You wont be judged by the book. You will be judged by the trees at the end of the runway. When you cant clear them the book will probably make it through the accident just fine. What Jesse and John Deakin are saying is "why not get the best performance you can out of every takeoff?"
 
lancefisher said:
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.
http://www.avweb.com/news/pelican/183094-1.html
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IMG_1133.jpg


Is the fuel flow gauge in the 172 she flys. The scale on it is kind of weird which makes me suspect that it's actually a fuel pressure gauge like you indicate above. I believe the 172R checklist calls for 3 to 5 gallons per hour after startup. There is no way a 172 at idle is burning 3 to 5 gallons per hour. Would you agree that it's actually fuel pressure and just guesstimating at flow?
 
jesse said:
IMG_1133.jpg


Is the fuel flow gauge in the 172 she flys. The scale on it is kind of weird which makes me suspect that it's actually a fuel pressure gauge like you indicate above. I believe the 172R checklist calls for 3 to 5 gallons per hour after startup. There is no way a 172 at idle is burning 3 to 5 gallons per hour. Would you agree that it's actually fuel pressure and just guesstimating at flow?
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IIRC, the 3-5 gph number comes from the priming sequence.

Also not there is no '3' gallon/hour mark. That needle is going to be somewhere between 0-5 gallons.

Even if it is calibrated correctly. It is an analog gauge, so its as accurate as you can interpret it. My digital FF readout will be within .1 - .2 gallons of total fuel used over full tanks used. (~65-70gallons worth)
 
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So it is actualy a true gallons per hour and not really pressure or what? I took that picture yesterday btw and yes it is on our before starting checklist. Its actualy what we're supposed to read when we turn the fuel pump on before start up.
 
jesse said:
(this) Is the fuel flow gauge in the 172 she flys. The scale on it is kind of weird which makes me suspect that it's actually a fuel pressure gauge like you indicate above. I believe the 172R checklist calls for 3 to 5 gallons per hour after startup. There is no way a 172 at idle is burning 3 to 5 gallons per hour. Would you agree that it's actually fuel pressure and just guesstimating at flow?
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It's hard to tell from the gauge. I think the POH would say whether or not it's a pressure gauge but maybe not. One way to tell for sure would be to check the shop manual. If there's a line running from the gauge to the fuel distributor it's a pressure gauge, if there are wires running from the gauge to a flow transducer in the line that feeds the distributor it's an electric flowmeter. Another idea would be to shut the master switch off while the engine is running and see if the meter still registers flow rate changes (electric flowmeter wouldn't).
 
There's even an easier way to tell what type of metering system it is, and to get information regarding its accuracy...
Ask your MECHANIC! If he/she has any working knowledge of your aircraft, they will be able to tell you exactly what the system is and how it works!

So many pilots who rent aircraft at a pilot center/ FBO seem afraid or unwilling to talk to the mechanics. But in reality, the more you do talk to them, the greater understanding you will have of the systems on board your aircraft and the better you will treat that aircraft. That in turn makes mechanics VERY HAPPY, and they will be even more helpful in the future. A WIN-WIN deal! :)
 
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