pilot "Sees the Light"
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
"I have always been too scared to try it"
says Dale. [Fred adds "...so was I until I went
to the 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
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:
Date: Sun, 3 Aug 2003
To: "Fred W. Scott, Jr."
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 and about 235,000 to
go! We'll get there.
Dale W. Hemman
Toll-Free 1-866-FLYTOAK (359-8625)
We forwarded that nice and funny email
on to George Braly - one of the developers of the
John Deakin; Walter Atkinson and they said that it
made their day!
Two days later, I received another email
from Dale at "Alaska
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
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
Another convert, Preacher Fred.
Dale W. Hemman
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 , a set of ,
and a little
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 its 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, (225) 925-2096
Incidentally, I have long wanted to put a set of 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.
While you are here, have a look at our horse
teams, and carriages, or take
a tour of our farm in central Virginia.