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POSTING RULES

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View Poll Results: When do you Lean?
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I start thinking about leaning before I leave the house
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94 |
62.25% |
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I lean above 3K feet or in a cruise altitude
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53 |
35.10% |
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I only lean above 3K feet
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4 |
2.65% |
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I'm rich in every sense of the word, I never lean!
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0 |
0% |

10-09-2012, 11:09 AM
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Join Date: Dec 2008
Location: na
Posts: 1,457
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Quote:
Originally Posted by RV10inOz
Yet another poorly written document from Lycoming.
In an attempt to create a one size fits all "cookbook" they have once again failed.
Interesting to not however they have finally addressed the issues of agressive leaning on the ground. About time!
No that is not what it says however what it does say is a bit of a shambles.
It talks about <3000' to leave it full rich, well I would counter that with why cruise below 3000 at full rich when a proper assesment of the power setting required would determine what is appropriate, but at 1000' and full bore, I use about 80LOP, and this is the most appropriate, unless I want the extra 4 knots, in which case 200-250ROP ( Full Rich) is the go but geez the fuel burn is horrendous.
Now what REALLY concerns me is this garbage.
So lets do that mental flight again....remember all altitudes. Now assuming the engine is not like mine, and many VAF'ers who have tuned their injectors, the point at which the roughness goes away may well be 60-80F LOP, however a factory C172 with a stock Lycoming may not be that good, most likley not, so where do you think this bit of leaning advice is going to get you? Maybe 20F LOP, 50F ROP? Who knows?????
Now of course the average C172 student may well pull the throttle back to 2300 RPM and in doing so the MP and RPM are such that the max possible power is around 65-70% anyway, but it does not specify anything, so full bore down the beach at 500' is possible!

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Are all C-172's equiped with approapriate engine instruments for precise LOP operations? If not, the Lycoming Service Instruction applicable to type certified C-172's and FAA (DER) Approved answers the need as intended.
I suppose the Lycoming engineers should take an AFS course since they don't seem to know anything about the engines they have been designing, manufactering and selling for a long, long, time.
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10-09-2012, 12:31 PM
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Join Date: Mar 2007
Location: Sonoma County
Posts: 3,821
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Quote:
Originally Posted by LettersFromFlyoverCountry
Yep, and it makes sense why we were taught that. As Mike Busch said, the CFI didn't want to give us too much to think about.
I've been working very hard to get into the leaning game the last few months and I loved the video. As I mentioned on my night flight the other night, I was at 3,000 MSL and could easily lean it out to 5.6-6 GPH (IO-360) which would be about 90-100 LOP and I'm still motoring along at 140 knots. But I'm just not sure how lean is too lean. Mike says just above engine roughness. Dare I? Just not sure. More experimenting needed. And haven't flown enough long cross country -- yet -- to do a lot of experimenting.
However, as I might've indicated on the original LFFC post (I can't recall, I might've only mentioned it on Facebook), I'm confused about WOT and leaning.
Busch said the ONLY time he pulls the throttle back is on landing; that he uses mixture to set power from takeoff all the way down. I'm just a fixed pitch grunt, and I'm not at all sure how that would work.
Also, I thought it was really interesting that he does not go full rich on landing. That, he says, is only in case you have to go-around and he says if you're confident enough in your ability to quickly do what you have to do in the event of a go-around, keep it lean.
I'm still thinking about whether I want to do that. 
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Busch was commenting on his C/S application. With your F/P prop, you would still use the throttle to control power...... rpm/mp.
With your FP prop, you needed to reduce power (rpm) as you approached and descended to pattern altitude. If you didn't make a mixture adjustment, and continued to reduce power, the motor would continue to run fine at low power settings. But if you gave it full throttle, the engine would stumble from a lean mixture.
Look at the mixture position leaned at 2000' agl and full throttle. You could do a go around with the mixture just a little richer than that.
During a go around, it's power and then flaps when you were training. I am sure by now we can handle.... mixture, throttle and then flaps with no problem. The motor will always tell you if it's too lean. But it has a harder time telling you that it is too rich. Just a loss of power that you may not notice depending on the situation.
__________________
VAF #897 Warren Moretti
2019 =VAF= Dues PAID
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10-09-2012, 01:50 PM
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Join Date: Jul 2011
Location: Dallas, TX
Posts: 321
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Quote:
Originally Posted by Subwaybob
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Quote:
Originally Posted by RV10inOz
No that is not what it says however what it does say is a bit of a shambles.
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That is EXACTLY what it says.
Quote:
2. Cruise
Make the fuel mixture Lean to maximum RPM (all altitudes).
Leaning Technique
a. Slowly make the fuel mixture Lean until the RPM decreases.
b. Make the fuel mixture Rich until the engine operates smoothly.
c. Make the fuel mixture Rich by turning the mixture knob an additional 1/2 turn
(approximately 180 degrees rotation).
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This document and the video states specifically that unless in climb or landing operation flying an IO-360-L2A to use these procedures "At All Altitudes". I translate that to most IO-360's from Lycoming and probably the IO-320's as well. Now I am not an engine scientist but these people are and I am fairly certain they would not put a document out that they can get sued for. Also keep in mind that the original service instruction that was superseded was 1497. With all that said my opinion is just that, an opinion. But since we have Gary flying with 5500 hours on his engine doing just what the document says to do I have to say I think I will go with it. (After the break in period of course!  )
__________________
Bob
RV-10 QB Here 8-25-19
RV-7
My brain shows a remarkable capacity to not willingly accept information that it considered useless.
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10-09-2012, 03:06 PM
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Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
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Quote:
Originally Posted by Subwaybob
That is EXACTLY what it says.
This document and the video states specifically that unless in climb or landing operation flying an IO-360-L2A to use these procedures "At All Altitudes". I translate that to most IO-360's from Lycoming and probably the IO-320's as well. Now I am not an engine scientist but these people are and I am fairly certain they would not put a document out that they can get sued for. Also keep in mind that the original service instruction that was superseded was 1497. With all that said my opinion is just that, an opinion. But since we have Gary flying with 5500 hours on his engine doing just what the document says to do I have to say I think I will go with it. (After the break in period of course!  )
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I'll have to go up and play with this but it sounds like this would put it about 20 or so degrees rich of peak. And everything I've been reading has said this is the last place you want to be.
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10-09-2012, 03:25 PM
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Join Date: Jul 2011
Location: Dallas, TX
Posts: 321
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Quote:
Originally Posted by LettersFromFlyoverCountry
I'll have to go up and play with this but it sounds like this would put it about 20 or so degrees rich of peak. And everything I've been reading has said this is the last place you want to be.
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I'm with you. Heat is bad. Excessive lead is bad too. I guess its a mesh of the two. I used to have a girlfriends dad that owned a crop dusting company with a few planes and was also an IA/A&P. He absolutely refused to use 100LL and only used pump gas. Said he had the cleanest engines ever! He also landed on the roads next to the crop to refill his tanks, so who knows, maybe he was just nuts! (No thread drift intended, just speaking about excessive lead...)
__________________
Bob
RV-10 QB Here 8-25-19
RV-7
My brain shows a remarkable capacity to not willingly accept information that it considered useless.
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10-09-2012, 03:52 PM
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Join Date: May 2005
Location: Brisbane Australia
Posts: 568
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I just put my vote in, I then viewed the poll, "I start thinking about leaning before I leave the house" seems to be what most of us do anyway. I guess that RED knob does something after all.
__________________
Jamie lee
Brisbane, Australia
RV7A - Now Flying.
0-360,carb,catto 3 blade.
VH-XJL
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10-09-2012, 06:19 PM
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Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
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Quote:
Originally Posted by Jamie Aust
I just put my vote in, I then viewed the poll, "I start thinking about leaning before I leave the house" seems to be what most of us do anyway. I guess that RED knob does something after all.
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The label under mine will soon say, "Pull for lower credit card bills."
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10-09-2012, 06:25 PM
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Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
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Subwaybob,
My apologies, I thought you meant literally, because just prior to that it said not below 3000' and it definately does not say anything about 1000'. But your point is correct, as I agreed, it implies at ALL levels lean for best RPM. I should say again, this would most likley result in a MP and RPM that is around 65-70% anyway, but that is an assumption.
My previous statement that this is yet another poor document from Lycoming stands.
RV8R999
Quote:
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answers the need as intended.
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you are kidding me right?? Subwaybob would not have started this thread if this document answered the need. It is a very poor document.
It is like teaching fying by saying, "keep the wings level and use the rudder to skid the plane in the direction you want". So what about everything else????
There is no cookbook answer to this, and the more Lycoming and the airframe manufacturers keep doing this stuff, the worse it gets.
Quote:
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I suppose the Lycoming engineers should take an AFS course since they don't seem to know anything about the engines they have been designing, manufactering and selling for a long, long, time.
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Not sure why the Lycoming engineers need to study an EFIS system built in the NW USA, but I am sure they would enjoy it.
The ENGINEERS at Lycoming know and should still know exactly what they are doing. They build a better engine than most, and they have a very good history of research, and understanding. Heck, they even developed and sold engines that were fitted to Piper's that were expressly to be run LOP, the manuals etc said so. The problem was too many OWT believers thought that they should run them a fraction richer than the book says, because a bit richer has to be better! And guess what, those folk had problems! So the evidence suggests give pilots the right info and they screw it up. It is no wonder the myths keep living.
Now lets be more realistic here, the documents coming out of TCM and Lyc for decades, have not been written by the engineers who know their stuff. Some of them are horrified with what has been published, and publicly admit it usually in retirement unfortunately. And often while attending an APS seminar.
I know where your { name calling removed} slant was heading, but if you understood, the course is not for the smart engineers at Lycoming or CMI, it is for pilots, those same ones who by virtue of 50 years of bad publications need all the training they can get. FACT!
gasman
Quote:
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I am sure by now we can handle.... mixture, throttle and then flaps with no problem.
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It is not hard is it 
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David Brown
DYNON Authorised Dealer and Installer
The two best investments you can make, by any financial test, an EMS and APS!
Last edited by Ironflight : 10-09-2012 at 10:07 PM.
Reason: It is not civil to call people names!
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10-09-2012, 06:42 PM
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Join Date: Jan 2010
Location: Hampshire, IL
Posts: 276
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For the past 17 years flying my Mooney 0360 A1A I've lean during ground operations and any altitude, I also lean during climb making any needed adjustments. Since I'm carbureted I do run 25-50 ROP, it works for me. 
__________________
Ed Martin
Bluskydtl
RV7
DKB
Donations 1/19 & 6/19
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10-09-2012, 07:53 PM
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Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
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This will come as a suprise to some people, but the rest of us get nothing from any point that uses name-calling to support it. But up until now it was an informative thread.
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