Destroyed the engine with excessive leaning?

There's also the notion of leaning for max power to get clear of obstacles, then more of a cruise climb to manage CHT's. Still want to be ROP, but also want to get off the ground first.
 
Hang 4 said:
There's also the notion of leaning for max power to get clear of obstacles, then more of a cruise climb to manage CHT's. Still want to be ROP, but also want to get off the ground first.
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Leaning for takeoff is mentioned only under the short-field takeoff performance table in our 1980 R182. There is also a misconception among some that leaning is for fuel economy rather than performance. I flew in the mountains for many years, where it was commonplace to ignore the POH and lean the mixture every time it called for "full rich". Why those checklists didn't bother to make a footnote about leaning prior to takeoff baffles me. Even the FAA resources on density altitude only focuses on leaning during cruise. Here is a classic video where the pilot shoves the mixture to full during a go-around from a 9000 ft elevation and barely makes it - but the video makes no mention of leaning. It only talks about loss of performance with altitude.
 
ateamer said:
I was taught right from the first lesson at a sea level airport to lean for best power on takeoff and landing. My CFI pointed out that even though at that field we pretty much always are at full rich, I will be flying to fields where it matters, and to get “full rich” out of my head and think “best power”.
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Unfortunately, too many people were taught best power is full rich.
 
Ed Haywood said:
Some aircraft are more prone than others. Usually 6 bangers. Hence the cowl flaps.
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Actually it’s really easy to design a 6 cylinder aircraft without cowl flaps that provide proper cooling in at low speeds, it’s keeping the engine at proper temperature in cruise flight without cowl flaps that is the issue.
 
MountainDude said:
Someone posted:
- Flying club member accidentally destroyed engine by running the temps too hot during their long flight.
- The A&P says the damage caused from long periods of excessive leaning and the flight data reflects dangerously high EGT's during that one members flight that would cause such damage.
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I saw that post, and I call BS - On the part of the A&P.

I've had a bunch of A&Ps tell me that I was gonna kill my engine running it LOP. I noticed that they were the same ones telling me I'd never make TBO in my IO-550 regardless of mixture setting.

I'm 500 hours over TBO now, and I don't listen to those guys any more.

I take off full rich unless I'm in the mountains. I lean in the climb (I have an EGT gauge with a helpful little green range marked "Climb" that's great for this), though that is still ROP. After leveling off and accelerating to cruise, I leave the throttle wide open (unless I'm on a low/short flight), pull the prop back to 2300, and lean until all 6 cylinders are LOP at a normal cruise altitude around 8-10K. If I'm higher, I'll lean closer to peak, if I'm in the oxygen altitudes I'll be rich of peak just to get more power.

MountainDude said:
Can someone explain to me what is excessive leaning?
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Well, if the engine quits, you have leaned excessively. ;)

MountainDude said:
Anything below 50-100 degrees LOP is going to stop detonating (my understanding), so you cannot lean any more.
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And in this case we're not talking about the bad "detonation" or "pre-ignition" or any of the damaging stuff, we're literally talking about making power at all. Yes, more than 100 LOP you're probably pretty close to the engine quitting if it hasn't already by then.

MountainDude said:
Also, how can a lean engine on a long flight overheat and be destroyed? I thought leaning was better for the engine.
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Starting from full rich, leaning is good, and then it's bad, and then it gets good again. Running at high internal cylinder pressures and high cylinder head temperatures is what's bad for the engine. That 50º ROP range that lots of people and documents recommend is about the worst place to be.

If you want to learn everything you need to know about running a piston engine, start here: https://avweb.com/features/john-deakins-engine-related-columns/

Ed Haywood said:
It mystifies me why we all quote Mike Busch as the authority and not Lycoming and Continental, who have serviced and warrantied far more engines than Busch will see in his lifetime.
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I was gonna type this all up but @Roger Wilco did it for me (quoted below). The guy who did the research is George Braly, and along with his friends John Deakin (author of the columns linked above) and Walter Atkinson they brought those findings to the rest of the community. Busch merely took that and ran with it. Braly is the only one of the original three who's still alive, so I'm glad someone (Busch) is still doing it.

Roger Wilco said:
I’m not a SavvyAviation customer, and everyone here should know by now that I have a low IQ.

Operating LOP is not a “Busch thing.” It’s a technique that has been researched and utilized at least as far back as WWII. A few decades back, George Braly developed a set of balanced fuel injector nozzles, tuned to each individual engine, so that LOP operation can be accomplished safely. Braly, at GAMI, built a test cell and has accumulated thousands of hours of data (not anecdotes). The Red Box (Busch calls it the “red fin”) was developed from that test data. Braly, along with Walt Atkinson and John Deakin, developed a roadshow they called Advanced Pilot Seminars that served as a training class to teach pilots how to operate LOP safely using GAMI injectors and an engine monitor, based on the data and lessons learned from testing and development. Busch seems merely to have adopted Braly’s research and operating principles. It’s worth noting that Busch’s SavvyAviators has collected and analyzed tens of thousands of hours (probably much more) of data downloads from customers’ engine management instrumentation*. My impression is that Savvy relies on that data when advising customers regarding engine issues.

If anything, GAMI and Savvy may be the most data-driven engine operation resources that GA has ever had. Now, tell me about the anecdotes you spoke of, and please dumb it down so that a low IQ person such as yours truly can grasp your point.

*Edit to add thousands of borescope images from customers’ engines.
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I should add, go read Deakin's columns and then we can talk. There's plenty of reasons not to like Busch, but he's not wrong, and Braly backs it up with real data.

kyleb said:
I agree. Busch is a maintenance guy. Anything he says WRT engine operating parameters is either anecdotal or second hand. I'm much more inclined to listen to Lycoming, Continental, and/or other researchers who do long term work with these engines on the dyno.
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Braly has done a lot of "long term work with these engines on the dyno."

Ed Haywood said:
My absolute favorite engine monitor feature is % HP.
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It's not that hard to determine even if you don't have it.

One way is that if you're normally aspirated, you can't be at more than 75% power above about 8,000 feet, and you can't be at more than 65% power above 11,500 feet. There's simply not enough air left at those altitudes to develop any more power than that.

If you're rich of peak, your power is limited by mass air flow; if you're lean of peak your power is limited by fuel flow. There's the old GPH * 14.9 = HP for lean of peak, so for my 280hp engine, 65% power is 182hp or 12.2 gph. For rich of peak, you can use (Actual MP/29.92)*(Actual RPM/Max RPM) to calculate the percentage of airflow compared to maximum. If you're at 25 squared on an engine with 2700 RPM max, (25/29.92)*(2500/2700) = 0.774 or 77.4% power.

This is how the engine monitors do the calculation, anyway... But neither formula is perfect. If you're way out at either extreme, you can affect the speed of the burn to the point where it's no longer as effective at being converted to mechanical power. For example, if you go to 100ºF LOP, you're probably borderline in terms of developing any power at all, and you'll certainly be less than 50%, but you'll still be pumping more fuel through the system than the formula would indicate.

Clip4 said:
Actually it’s really easy to design a 6 cylinder aircraft without cowl flaps that provide proper cooling in at low speeds, it’s keeping the engine at proper temperature in cruise flight without cowl flaps that is the issue.
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FWIW, my M20R Ovation is a 6 cylinder aircraft without cowl flaps that does quite well with cooling at most speeds. I do tend to climb with faster airspeeds most of the time, but that's just because I want to go fast and Vy to altitude isn't fast. My Vy is 105 KIAS, book cruise climb speed is 120 KIAS, and in lower altitudes I usually climb at "Vz" which is 138 KIAS in my plane and still do over 1000 fpm.
 
sarangan said:
I agree, this is a great resource. I read some of them a long time ago, but it looks like Avweb has taken down those articles. I hope they are hiding somewhere else.
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Ugh. Yeah, every time they update to a new CMS for their web site, all the links to the old stuff breaks, even from their own pages.

It is possible to Google the titles from there and find the articles still. For example, one of my favorites, "Manifold Pressure Sucks" is available here: https://avweb.com/features/pelicans-perch-15manifold-pressure-sucks/
 
flyingcheesehead said:
The guy who did the research is George Braly, and along with his friends John Deakin (author of the columns linked above) and Walter Atkinson they brought those findings to the rest of the community. Busch merely took that and ran with it. Braly is the only one of the original three who's still alive, so I'm glad someone (Busch) is still doing it.
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One name that doesn't get mentioned in that trio and absolutely should is Carl Goulet. A pretty great read.

 
flyingcheesehead said:
Ugh. Yeah, every time they update to a new CMS for their web site, all the links to the old stuff breaks, even from their own pages.

It is possible to Google the titles from there and find the articles still. For example, one of my favorites, "Manifold Pressure Sucks" is available here: https://avweb.com/features/pelicans-perch-15manifold-pressure-sucks/
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Manifold pressure sucks, Mixture magic, and those Marvelous props are 3 that should be required when transitioning to anything with a blue knob.
 
Palmpilot said:
Actually, AvSig was on the Internet, via Compuserve.
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Well.... yes and no. AVSIG did start on CompuServe, but back then it was on ARPNET. Then Jan. 1, 1983 ARPNET start being called the "Internet."

For those unaware of AVSIG, it was the first Aviation related "Bulletin Board" and was actually the first public Bulletin Board. Some will dispute the Board that the programmers (as they were called back then) used in setting up CompuServe was the first... But even some of those members would confirm that their Board (I forget what it was called) was not public (as were others being created by other endeavors). So AVSIG really does have the #1 spot as the first public forum.
 
M20K said:
Well.... yes and no. AVSIG did start on CompuServe, but back then it was on ARPNET. Then Jan. 1, 1983 ARPNET start being called the "Internet.
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Well, not quite.
First, it's the ARPANet (as in Advanced Research Projects Agency) who was responsible for the net. The ARPAnet migrated to the Internet protocols on January 1, 1983, but the Internet existed before that, and the ARPANet continued to exist as part of the Internet after that. It was never proper to refer to the terms interchangeably.

Compuserve was a completely different thing. Compuserve started as a dialup information service provider which is where AVSIG lived. They also provided other communications networking services, but didn't step into the Internet Protrocols until 1989. Even then it was a while before Compuserve's sigs and forums became accessible but the internet pretty much killed that aspect of Compuserve and a couple of screwed up aquisitions (notably finally AOL) pretty much killed it.

AVSIG moved from a Compuserve "bulletin board" service to an independent website Bulletin Board, before reformatting itself as an Aviation News Serivce.

It was the old Compuserve-Based AVSIG back in 1982 that I posted that I needed a ride to Oshkosh and got Paul Bertorelli to offer to take me.
 
flyingron said:
Compuserve was a completely different thing. Compuserve started as a dialup information service provider which is where AVSIG lived.
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How quickly we forget. :D I was thinking more about CompuServe's main business.

Sort of miss those old modem tones... NOT!
 
Palmpilot said:
Actually, AvSig was on the Internet, via Compuserve.
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Not originally... Ron's got it right. All of the old online services did eventually connect to the Internet in an unsuccessful effort to remain relevant, but none of them were on the Internet when they started except maybe eWorld.
 
Ed Haywood said:
I used to enjoy regaling my kids with stories of life before the Internet. Yellow pages, road maps, Sears catalog, encyclopedias. Seems a world ago.
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Thinking the same thing the other day. Remember that game show where for a million dollars you had to answer a question? You could call a friend and he or she could tell you in 30 seconds and give a percentage on how right they thought they were. Wouldn’t work today unless they quarantine them.

One question was what Letter is in front of all US registered aircraft tail numbers.
The guy called and got the correct answer.
“N”
 
Ed Haywood said:
I used to enjoy regaling my kids with stories of life before the Internet. Yellow pages, road maps, Sears catalog, encyclopedias. Seems a world ago.
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Pay phones, telex machines, water fountains. A young man came into the office for a job interview a decade ago and spotted an old IBM ball type typewriter and asked, "what's that?" In my case, pagers became the first real leash attached around the neck for near instant communication (like it or not).

Sometimes it seems all the new electronic devices we now need and use were designed many years ago and cycled into our world to maximize profits... planned obsolescence.
 
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