The previous article was selected for publication in the September 2003 ABS NEWS and as I was headed to Alaska with our group leader Dale Hemman of LetsFlyAlaska.com, the article was faxed for proofing to Quesnel BC. Dale is a very experienced bush pilot who owns a lovely and beautifully equipped Debonair with a TurboNormalized IO-550 Continental engine. He read the printer's proof and was quite interested. Several days later, he rode with me from Whitehorse to Fairbanks and asked "Please show me how you operate Lean of Peak"

I told him to close his eyes, and pull the mixtures back until the Baron just slightly deccelerated. He did, and then he asked "How did I do?"

The fuel flows were within 1/2 GPH of the correct setting.

"Try again" I said, and the second time he nailed them to within 1/4 GPH.

"Well. I'll be darned" he commented. With his eyes open, he then used the JPI to fine-tune the settings. and five minutes later the EGTs were at about 1450dF or so and the CHTs at 300dF or below. The 1800 hour engines purred quietly and the burns were at 11.4 each side.

"I have always been too scared to try it" says Dale. [Fred adds "...so was I until I went to the Advanced Pilot Seminars in Ada"]

After the flight, we were post-flighting the Baron and I showed Dale the oil on the dipsticks. At that point, we were at 35 hours or so since new oil. He said "It looks like you just changed all the oil" and seemed impressed that it was so clean, the reason for which is explained in the previous article.

Two weeks later, I was back home in Virginia and got the following email from Dale Hemman who was again back in Alaska leading a subsequent group of airtourists:

From: "Alaska Guide"
Date: Sun, 3 Aug 2003
To: "Fred W. Scott, Jr."

Fred,
I am in Homer AK at the moment and since it is Sunday I thought I would write and let you know that I have been to church both yesterday and today. Yes, I must say, I feel the POWER!

In case you haven't surmised, I'm talking about the Church of the Lean of Peak! I spent the past two days in the left seat with a fellow on the trip who has an F-33 Bonanza with an IO-550. He asked me if I would fly and let him sit in the back so he could take pictures out of the back. It was fine with me and his passenger didn't care who was flying the left seat so it worked out great. When I did the pre-flight yesterday, I noticed he had GAMIjectors so I jumped to the assumption that he had also "been to church". After all, why buy the alter and not accept the sermon? Anyway, as soon as we were at cruise altitude I set up for LOP just like "Preacher Fred" showed me, with my eyes closed. This was the first time I tried it and I am glad to say that ...

Yes brother, the blind can see!

The aircraft owner, Bill, noticed the fuel flow down at 9.6 GPH and about had a cow. He thought something was wrong with his gauge because the EGT was reading right where he normally sees it (1410dF) and his CHTs were a bit cooler than normal which he attributed to the cooler air. He asked me what I thought was going on. I told him everything was just as it should be from my perspective and he said that couldn't be because the fuel flow should be reading 15 to 16 GPH.

I told him that I had seen his GAMIs and just assumed that he operated on the lean side of peak. He said that he did not and I asked if he would like me to return to the rich side and he said "Yes".

I pushed in the mixture under his watchful eye and the EGTs went up and then came back down to 1410dF where we had started .... 50 degrees above peak, but on the rich side now. The fuel flow went from 9.6 to 15.5 and the CHTs went up from the 310 (average) to 360. Everything was back to where he normally operated.

I didn't want to try to convert the unwilling so I just apologized for assuming he operated LOP and not asking. I said that since I had seen his GAMIs I just assumed he bought them for the fuel savings and benefits you would expect from operating LOP such as potential extended engine life due to better cooling, less plug fouling, and less oil consumption. He just said that he operated ROP and we let it go at that.

Today he asked me to fly him again and I was happy to do so. Once we got airborne he asked me if I was going to fly LOP again and I told him I would just operate his airplane the way he wanted me to rather than the way I might operate mine. He told me he had been thinking about what I told him and that he wanted to know how to do it himself. Sensing that he was ready for the alter, I told him that all he had to do was shut his eyes and lean out until he could hear the sweet smooth sound of LOP [Editor: in other words, when the pilot feels the plane just slightly begin to deccelerate]. I then demonstrated for him and I know there is another convert out there.

Yes "Brother Fred", you have done well. You have gone forth and multiplied! You have spread the word to me and I have spread the word to Bill and I know it will continue. That's two converts down for the Preachers in Ada, Oklahoma and about 235,000 to go! We'll get there.

_____(o)_____
Happy Landings
Dale W. Hemman
LetsFlyAlaska
253-841-4134
Toll-Free 1-866-FLYTOAK (359-8625)

Two days later, I received another email from Dale at "Alaska Guide"

Fred,
We had an absolutely lovely two days here in Valdez. The sky has been cloudless and the seas and winds absolutely calm. It's been a wondrous time.

As miraculous as the weather has been, I'm writing about a different miracle. You recall the fellow with the IO-550 powered F-33 I told you about who I showed LOP to? Well, his non-pilot passenger today told me that enroute to Valdez yesterday he had been "fiddling with the mixture" and he said that Bill (the aircraft owner) suddenly said "Oh wow! That's the lean of peak Dale was talking about" He said Bill was excited the rest of the way and was explaining it to him like he had just discovered gold. I think we have another believer.

Now here's the kicker. Remember, on the phone I told you about the A-36 owner who wouldn't even consider LOP? He now wants to stop by Puyallup on his way back to Ohio just so I can ride with him and show him how to do it since Bill is so excited about it. His A-36 is probably about the nicest one I've seen and he needs to treat the engine the same way he treats the rest of it.

Another convert, Preacher Fred.

_____(o)_____
Happy Landings
Dale W. Hemman
LetsFlyAlaska
253-841-4134
Toll-Free 1-866-FLYTOAK (359-8625)

Fred adds: In spite of Dale's teasing about "Preacher Fred", please note that I'm not "selling" anything. I really do not care how you operate your engines. I post these comments simply to have a coherent way to explain a complex subject that I am capable of understanding, but I neither teach this subject nor do I encourage closed minds to open up. That's entirely up to you. Do you want help? I'd be happy to offer what I believe to be good science, or send you to smarter people, but always remember that to succeed, it takes four things: a team of committed mechanics to set the engines up correctly, a full engine monitor, a set of GAMIjectors, and a little knowledge of what do do with all of this old and time-tested, but recently rediscovered information.

Nor is it as complicated as many think ... if you believe in KISS (Keeping It Simple, Silly) principles, there is even a simpler way. You do need the JPI monitor to set the engines up exactly precisely, and it’s fascinating to learn more from that instrument... and to diagnose troubles later, but it is perfectly possible to operate quite safely LOP if you use a simpler procedure... even without the JPI monitors ... and, sometimes, even without the GAMIjectors. (Over-water ferry pilots have done it for decades).

For Seminar schedules, contact Walter Atkinson, Advanced Pilot Seminars (225) 925-2096

Incidentally, I have long wanted to put a set of Colemill IO550 engines on this Baron when these IO-470s got tired, and finally - at about 1900 hours - they said "enough". A few compressions were low as we changed the oil after this 100 hour Alaska trip (all the way to Prudhoe Bay, out over the ice, up in the mountains and down in the glaciers), so we headed for Nashville, Cornelia Fort Airpark in August 2003.. And do we run the new engines? ...the same way, of course.. It sure helps when Doug Colbert sets the engines up as rich as he does. I can always make them leaner, but there is no "More Rich" control available at Takeoff Power. That's where the good shops come in -- it's critical that they understand these mixture and timing issues. Takeoff Fuel Flow is a very important setting. Our Colemill Baron takeoff flows are set rich at the upper TCM flow limit, the cylinder heads run at ~330F max in a summertime climb, and much cooler in cruise, with flows as low as 10 GPH per side when we are loafing along at 180 KIAS. Or we can run at 12,000 MSL all day long at 12.5 GPH per side with True Airspeeds just above 200 knots. Life is good!

Do you prefer a video explanation? See this superb summary from Martin Pauly; it's so clear and so well done that it's added here 15 years after the original article was published. It's 25 minutes, but absolutely worth the time.

Any questions? just give me a call, or click on the e-mail link below.