With throttle wide open and mixture between full rich and peak EGT.

 

Close enough for, flight sims... :D

Close enough for, flight sims... :D

LOL. It's pretty surreal posting this sort of stuff when I've never even touched the real deal.

I would never lean on Takeoff. This is stipulated in the Pilots Operating Manual for the C-172.

 

I have looked at a number of models for the C172 (C172L, C172M, C172N, C172P, C172R, C172S, C172SP) and in the POH of every one of them it specifically states something like:

• "Prior to takeoff above 3000 feet pressure altitude, the mixture should be leaned for maximum RPM at full throttle with the airplane not moving"... and there's the caveat about operations around gravel...
  

Even in my 1980 C152 POH I have says the same thing.

 

My PA-28-161 (Piper Warrior) has a bit more nebulous recommendation ("minimum amount of leaning for smooth operation at high altitude"). Some time spent with the Lycoming SI on leaning would be a good thing.

 

Larry's post is most correct -- the voice of experience (I used to lean for taxi too Larry... pulled it way back and this was at about 1000' MSL).

 

With modern tuned injection engines there is really no benefit to running RoP unless you absolutely need 100% of a given power percentage.

 

If you read Lycoming SI 1094D... on page 6 that very same chart is used.

 

The last Note states the following:

 

"TEXTRON LYCOMING DOES NOT RECOMMEND OPERATING ON THE LEAN SIDE OF PEAK EGT."

 

fwiw btw.

 

=================

 

The bottom line folks:

 

Read & Heed the WHOLE POH (actually the AFM for the specific aircraft you are flying). In absence of an AFM, do what the Engine Manufacturer says to do (e.g. more than once I have posted a link to Lycoming's Service Instruction on Leaning Procedures).

Just because the POH is the authority, that doesn't make it right. Looking through a number of them, their recommendations haven't changed in 30+ years, ignoring advances in engine technology. At the time they were first printed you'd be crazy to run lean of peak due to single probe EGT/CHT readouts and injectors that hadn't been tuned. Now with GAMIjectors and multi-cylinder engine monitors, LoP is a viable way to fly that both saves fuel and runs the engine cooler. I can't see a downside to that.

 

John Deakin, pretty much the go to guy for LoP, basically says to ignore the POH rules for throttle/prop/mix, except when getting certified. After that, run it the way science has shown to be best, LoP.

 

Some more reference material: The Great Leaning War

I suspect that many "recommendations" are based as much on potential liability fears as on empirical data, perhaps even from simple lack of evidence supporting the alternatives. I run into that a lot (in all aspects of life).

 

It's safe and easy to operate correctly RoP. They know you shouldn't get any trouble doing that, so they suggest you do so. Running LoP, however, requires more caution. A pilot has more ways to run into trouble doing that.

 

From what I've been reading, on some newer planes, the builder actually specifies that LoP is not only approved but is recommended, with RoP operations to be avoided in a cruise setting.

I suspect that many "recommendations" are based as much on potential liability fears

 

A choice quote from the artice I linked above:

Lycoming objected-and still objects-to lean-of-peak operation, claiming that it of itself is not harmful, but owners lack the instrumentation to do it correctly. Somehow the multi-probe engine monitor and, lately, MFD engine analytical pages the size of a small television, escaped them.

Just because the POH is the authority, that doesn't make it right.

 

I can tell you this... it makes it safe... which is what I am most concerned about.

 

ignoring advances in engine technology.

 

I have followed the aircraft industry for a number of decades.... one can see that there are very little "advances" in engine technology.

 

Now with GAMIjectors and multi-cylinder engine monitors

 

I used to install the Insight GEM and tuned injectors have been around for a while... but very few of the GA fleet has these types of things installed.

 

I can't see a downside to that.

 

Cost (product & install as this isn't a "do-it-urself"). Is an STC available for the particular aircraft... etc.

 

After that, run it the way science has shown to be best,

 

Could be in terms of nmpg.. but that is not the only factor involved.

 

John Deakin, pretty much the go to guy for LoP, basically says to ignore the POH rules for throttle/prop/mix,

 

If his recommendations line up with the Engine Manufacturer... sure ok... if not... no thank you.

I'll stick with Deakin, thanks. I prefer science over tradition.

Nothing wrong with putting safety first, but as a former aviation-safety professional, even I won't say safety can be the only consideration. "Safety-only" means never leaving the ground.

 

There's more than one right answer to the "leaning" question... which is why you find so many different opinions. The wrong answers are the ones that lead to the engine quitting.

I'm surprised no one has brought this up before.

 

Be very cautious when dealing with someone who made his name advocating the opposite of accepted practice. What happens is, if you take some element of accepted practice, postuate the exact opposite is true, then work back to something that makes sense, and you can get this published, people will remember who you are.

 

I saw a guy get a full double page spread in a newspaper by saying there was never a better time to lease a car when everyone else said leasing was a Very Bad Thing. He ran a leasing agency. That's the kind of promotion that money can't buy.

 

A good example of someone who does this, and not aviation related so it shouldn't step on as many toes here, is Evelyn Woodhouse, the animal "expert." Read anything she wrote. If you know a lot about animals, you'll see what I mean.

 

I have problems reading Deakin for this reason. Watch how he defends something. Notice that he doesn't explain some things very well, which is a good indicator that he doesn't understand them well himself. Lots of red flags.

 

I'm not saying he's wrong. I'm saying "be on your toes." Not all of his advice may be good.

 

Sorry guys. I'm just a little bit cynical.

 

Hook

I'll stick with Deakin, thanks. I prefer science over tradition.

 

I prefer to stick to the recommendation of a company that has been building engines for over 80 years... and has not hundreds, or thousands, but tens (if not hundreds) of millions of hours on their engines.

 

...than one person who has a few hundred hours of anecdotal evidence.

 

I'm no pilot either, but all the real world things I've read line up rather well with what's in game.

 

Absolutely amazing.

 

Now... I have seen some good posts from you. But... you say you are not a pilot, zinfinion... yet you would take the word of one man because it makes some "scientific sense" to you.

 

Not a pilot... and haven't operated aircraft engines?

 

Ok... let me tell you a bit about me...

 

I have operated aircraft engines... a wide variety of them. I have torn them completely down and put them back to (working) order. I have a Commercial Pilot's license. I hold an FAA Instructor's License (CFI - for two decades) with multiple ratings (CFI for Single & Multi-Engine Airplanes and Instrument Instructor for Single & Multi-Engine Airplanes). I hold an FAA Aircraft Mechanics License with Airframe and Powerplant Ratings... I have also worked as an A&P on GA aircraft (up to King Air). I hold a Bachelor of Science degree (graduating "With Distinction") in Aeronautical Engineering Technology and a Minor (A.S.) in Flight from a very distinguished University (same one Amelia Earhart was faculty... and who funded her flight in which she disappeared). Am now working on my Masters degree in Aviation. All told I have spent well over $100,000 U.S. on my Aviation Education (with very little monetary return btw when gaining work experience).

 

So I am not some rube when it comes to things Aviation. Just your "Advanced Student" so to speak.

 

And you are going to suggest I listen to "Deakins" (whoever that is btw) because it lines up with a game or sounds scientific? You are going to have to do better than that.

 

 

"Safety-only" means never leaving the ground.

 

Maybe to you Ray... maybe that is your definition... not mine. If I cannot conduct a flight "safely" I don't fly (wow what happened to your safety first, second, third?). But that was typically not the case. Nothing out there says I have to have an accident.

 

But then... maybe there is... if I start disregarding the POH... the Eng. Manf. for some webz writer.

 

There's more than one right answer to the "leaning" question...

 

Sure is... based on make and model of the engine. Do it your own way or what some (careless) instructor teaches and you are begging for trouble.

 

Sorry guys. I'm just a little bit cynical.

 

Excellent post Hook.

 

A good example of someone who does this, and not aviation related

 

Here's a good Aviation example. Mobil AV-1 (full synthetic). Only oil I know of that was STC'd for 200 hour changes (normal oil changes are at usually 25 or 50hrs).

 

Very popular oil in the early 90s from (at the time) a very popular oil company. STC has since been pulled by the FAA and the oil is no longer on the market. Very interesting story this one. Good to look up and read about.

 

Sorry guys. I'm just a little bit cynical.

 

And rightly so... you should question... you should question me or anyone else when you think you are not getting the straight scoop. I'll do my best so that we learn together and increase our knowledge of all things Aviation... but I will be the first to tell you "I could use an extra set of eyes"... i.e. I have brain farts and make mistakes from time to time, but you will never find me trying to b.s. my way thru something.

 

You should be cynical... because Aviation (piloting an aircraft) is "terribly unforgiving" and you have a right to be told what is "right" or "safe" or in keeping with good practices since this is part of your "pursuit of life, liberty... and happiness" (to paraphrase)... yes, there is much joy and freedom in flying a plane... but to a greater extent, much responsibility on our part to fulfill what it offers.

I just realized... I believe that Mr. Deakins makes the Gami-jectors. If that's the case, then all bets are off concerning anything he says. It's ALL marketing and promotion. You can't get his results without using his injectors. He's going for mindshare. I'm going to trust the engine manufacturer over this guy in any case.

 

It reminds me of the Saitek yoke with the metal rod. You'd think the metal would be much better than the plastic, but it turns out not to be the case: metal is "stickier" than plastic, more friction, so the action isn't as smooth. The plastic rod won't break in the CH yoke. Another insane example is the Kirby vacuum cleaner. The current version is made of titanium, for chrissake. Steel is too heavy, aluminum would be just as good. Titanium does give them some bragging rights and allows them to jack up the price. But the vacuum cleaners are awful anyway... for 5 to 10% the price you can get a good Wunderplastik Hoover that's lightweight and a marvel of ergonomics. Kirby was designed in the 30s and looks it.

 

A good friend of mine had a Honda Civic. After the break-in period, he ran nothing but Mobil 1 in it. Mechanics had strict instructions not to change the oil or mess with it in any way. I think he said he had some crazy high mileage on it when it took it in for a checkup once, like 80,000 miles. When he went back to pick up the car, the mechanics said it would be ready shortly, they were putting the cylinder heads back on. "Huh??" Turns out they'd never seen an engine that clean and wanted to see what it was like inside. Apparently little to no wear. Seems like good stuff. Was there anything else going on that I should know about?

 

Hook

Looks like everybody's getting too deep into all of this LOP stuff. I'm active on the "experimental" forums. The majority of engines used are Lycomings. Those of us that are familiar with what's going on these days..............know what Lycomings position has been. They were not in favor of LOP, and that's mostly because it was easy to damage the engine if operated incorrectly. And that mostly had to do with lack of instrumentation. But.............Lycoming has come around to the idea. These days, with precision CHT & EGT for each cylinder, and injectors sized to maintain a more consistant temperature with each cylinder.......with fuel injection, it's becoming the norm to run LOP, and Lycoming isn't complaining.

 

As to flight simming, I'm quite sure that precision engine management isn't in the cards as far as ROP & LOP operations go. I just lean until rough, and richen it up a bit. I know that FSX starts getting critical for leaning around 6000'. I don't know what Flight does, as I'm not really using it. I also know that FSX requires a longer takeoff distance at higher altitude airports, and that is good.

 

L.Adamson

Anyone I am about to fly with starts talking about how they disagree with what is stated in the Pilots Operating handbook, is quickly told by me......." I just decided, I don't feel like flying today.... Have a nice flight, I'll walk back to the FBO..........

Was there anything else going on that I should know about?

 

Were you asking why ok for autos and not aircraft engines? Briefly... engine tolerances much tighter in autos... the lead in AVGAS...

 

Here's an article by Kas Thomas in TBO Advisor about Mobil AV-1 and the 'why the class-action lawsuit' that had been filed against Mobil: http://kas.e.thomas....s.com/Mobil.pdf

 

 

Thread on GAMIs @ SOAPA: http://www.337skymas...hp?threadid=582

 

Post #2 by Ernie Martin pretty much sums up the matter.

 

As to flight simming

 

With all the gazillion hours I have in FSX (how I wish were RW hours!) I have always used the automixture checkbox. I have experimented somewhat being an RTWR'er hoping to eek a few extra knots by leaning... seemed to make absolutely ZERO difference in airspeed in what few tests I ran.

 

Anyone I am about to fly with starts talking about how they disagree with what is stated in the Pilots Operating handbook, is quickly told by me.......

 

I can remember just saying, "you're clear I am PIC?" :lol: or I would walk... unless the person could demonstrate otherwise... e.g. from something like an AD or SB (Airworthiness Directive - Service Bulletin).