I had spent an adult lifetime, now approaching
4000 flying hours, in my own aircraft - beginning with
a Cessna 175 Doyn conversion, then a Bonanza 36, a Baron
BE-58P, followed by a Cessna Caravan and now a BE-55
Baron. Always interested in learning more, I trained
at FlightSafety for the initial couses in the P-Baron
and Caravan, have attended the BPPP clinics several
times, and work annually with private instructors on
recurrency, as well as reading widely. So I felt that
I was "up-to-date." Well, maybe not!
Comments by some of the "Beech-listers"
began to get me interested in their experiences - and
particularly those running on the lean side of the Exhaust
Gas Temperature (EGT) curve. Having had a full engine
monitor in the P-Baron, I was generally familiar with
operation and interpretation of those earlier instruments,
but was reluctant to install such a monitor and balanced
injectors on my B55 with its IO-470 engines aproaching
overhaul. The cost of the
was about $7500 installed and it made little sense to
add GAMIjectors when I was considering a Colemill upgrade
at overhaul time.
Nor did I have any particular interest in running on
the lean side. "You are not supposed to do that"
is what we all were taught back in the sixties. In addition,
I am pre-inclined to trust both Beechcraft and Teledyne
Continental Motors which does not encourage the LOP
(Lean-of-Peak EGT) technique in any of my aircraft POHs
and even less inclined to listen to a few people in
a small shop in Oklahoma who I had never heard of.
But I had been reading Braly's comments carefully and
became convinced that he knew his stuff. Deakin's articles
on AvWeb - on engine management - just reinforced my
confidence, and particularly as to the takeoff fuel
flow setups. So, my maintenance crew at Virginia Aviation
and I actually spent some considerable time learning
how important it was to have fuel pressures set up so
the engines are rich enough at takeoff to keep the cylinder
head temperatures down. Ultimately, I just came to believe
that a JPI-GAMIjector combination might make the engines
run smoother. I slowly decided to bite the bullet.
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.
The was available and it offered
new functionality well above and beyond my older-technology
P-Baron monitor. suggested that I install this monitor
first, getting to know how it worked while learning
how to interpret the data it produced. Then, he suggested,
we could add the GAMIjectors and try to smooth out the
engines which - with stock injectors - really would
not run smoothly at or near peak Exhaust Gas Tempartures
(EGT) as shown by the factory single-probe gauge.
The Twin was installed in June 2002 and this pilot began
a journey of discovery. The first thing to happen was
an engine failure on takeoff,
- caused by a blocked fuel line -but that's another
story, unrelated to this one, except that it was extremely
educational as to how the
trapped JPI data can be used in a "what happened?"
I found the data analysis interesting and -- with the
good help of ABS members Ed Livermore from San Antonio,
and Jim Shannon here in Virginia -- learned how to use
MSExcel to graph the massive data sets that were stored
by the JPI. The folks at JP Instruments were exceptionally
helpful, too -- particularly, Scott
Kelleher at JPI technical support, who patiently
answered a lot of my dumb questions. "How to download
to a Palm, sync to a Windows CPU, decompress and email
the file to my iMac and then analyze the data?"
A bit overwhelming at first and admittedly awkward,
with his help this is now a routine procedure.
Having learned how to interpret what the data was saying,
I then installed the GAMIjectors in my two engines that
were approaching recommended overhaul times. Sounds
crazy? Maybe, but I knew they were in really excellent
shape, on oil analysis, with no problems whatsoever
and we were clearly going to be able to run well beyond
TBO, as many IO-470s do routinely. In fact, I was planning
to take the engines and the plane to far north Canada
a few weeks later. (This travelogue was reported in
the Feb 2003 ABS NEWS and is
also available here ).
We installed the GAMIjectors and immediately began analyzing
data and swapping out injectors to make the peak Exhaust
Gas temperatures occur at the same time - smoothing
out the engines as we did so, while searching for the
minimum "GAMI lean spread". That initial learning
period was interesting because it created a lot of emails
and opportunities to learn more. But we immediately
had problems in the installation. The engines got better
but would just not smooth out.
After some discussion with the immensely helpful John-Paul
Townsend at GAMI technical support, George Braly
suggested that we had an induction leak on our engines.
Sure enough. Several of the intake manifold drain line
checkvalve balls were missing from their seats on each
engine. These are sucked closed by the vacuum within
the intake runners as the engines are operating (remember
that 15 " showing as manifold pressure is really
a partial vacuum to the extent of the difference between
the 15" on the gauge and the ambient pressure at
the aircraft's altitude). When we replaced the checkvalves,
the right engine went smooth as butter, but the left
That's why they put two engines on Barons; to drive
the owners nuts trying to get everything and every gauge
to match exactly!
Braly said we still had an intake leak on the left side.
I said we did not, because Randy
Tucker's really good crew at Virginia Aviation in
Lynchburg VA had becomeinterested in what we were doing
and had looked hard at the intake plumbing. They had
pressurized it and could find no leaks. I shrugged it
off and kept running the engines the way I always had,
at about 50F or so on the rich side of peak. The engines
were still much smoother than they had been...and we
headed to northern Labrador. I could not have been more
pleased with our progress, but the left engine still
would not run really smoothly on the lean side of peak
when I occasionally experimented, and being a picky
aircraft owner, I still wondered if I could improve
things. I kept changing the engine oil as the levels
went down to eight and put in new oil about every thirty
or forty hours. The whole time the engines were not
leaking, but they did blow oil out the breathers, making
a small mess aft of their mounts and along the flaps.
About this time in my process of discovery, we on the
Beech Owner's list began to hear from our three "Preachers"
-- Braly, Deakin, and Atkinson -- that they were going
to host an in Ada, Oklahoma at the GAMI facility
so as to be able to use the world's most advanced piston
aircraft engine test stand. On the test stand, a fully-instrumented
engine is configured with special pressure sensors within
each cylinder chamber and a beautiful display of what's
happening inside each. It is possible to see the internal
peak pressure pulses - the height, shape and duration
of which can signal the difference between normal operation
and detonation. For schedules, contact Walter Atkinson, (225) 925-2096
I signed up for the second class, and arranged to come
out early and let the GAMI shop figure out why the left
engine 2,4,6 cylinders were leaner than those on the
right side of the engine. I flew out in my Baron with
USMC Col. Ron Gatewood, the operator of Warrenton Flight
Center in Virginia, and owner of a Piper Chieftain which
has very complex turbocharged engines.
The day before the Seminar began, Ron and I watched
the GAMI crew pull off my left-side induction airbox,
and re-run all the previous tests, and ... as I suspected
... there were no leaks, which puzzled us all. Instead
of giving up, everyone at GAMI got more interested and
I must add that GAMI has the sharpest bunch of engineers
and aircraft mechanics I have ever met. After lots of
serious discussion and hair-pulling, GAMI's chief of
maintenance, David Landreth, noticed that the curved
inside throat of the airbox divider was shinier on the
left side than on the right side and suggested that
the cause was the extra flow of air after 5000 hours
on the airplane. But why? The intepretation was that
while the induction system was perfect as to leaks and
design, some tiny anomaly existed which offered less
resistance to the left side airflow (or more to the
right side) with the result that the 2,4,6 cylinders
were running leaner than the right side 1,3,5 were.
We discussed some different approaches to correcting
the problem and when I got home we reworked the airbox
and logrunners just slightly so the left engine began
to run just as smooth as the right engine. While we
were at it, we installed the GAMI "hole-in-the-wall"
baffling fix to keep the number six cylinder heads cooler.
That worked, too, by ~30dF. Now, we are getting somewhere!!
In the meantime, off we went to the . The comprised three of the most intellectually
stimulating days I have ever spent in aviation, since
I began flying in 1965. I think I know my Baron well,
but I'm sure I know more about safe and wise operation
of my engines today than I did before the seminar! running on the fully-instrumented test stand
just enhanced the experience. (The engine can, while
running, switch over to PRISM automatic spark timing
and/or use three types of fuel - including autogas).
The participants would ask the presenters about a situation,
and the engine could replicate the condition.
Ron Gatewood and I arrived at Ada to find the same engine
used in his Piper Chieftain -- the complex Lycoming
TIO-540 J2BD -- running on the GAMI test stand. On the
first engine run while using Piper's Chieftain POH settings,
we saw that engine running into near-detonation on every
got interested, real fast. In fact, before our seminar
was over, he called home from Ada and told his crews
to change their operating techniques immediately.
In my opinion, the folks at GAMI are going to change
the world of piston aviation for the better, and they
have the hard science to back up their ideas and claims.
The really clear and fabulous slide presentations, and
the "let's keep going" attitudes of John Deakin,
George Braly, and Walter Atkinson made the Seminar fast-paced
and really fun... even when our brains were nearly overwhelmed
with new information... a new way of thinking.. While
I had previously read most of the literature that was
discussed, the seminar put all the engine management
issues into context far, far better than my "home-study"
had done. The instructors emphasized that the principles
discussed applied to any piston engine: Harleys, Briggs
& Strattons, Continentals or Lycomings, GreyMarines,
Curtiss-Wrights, Pratts, etc.
Incidentally, I have heard some pilots (who have not
attended the seminar) say that all the Seminar teaches
is how to run on the lean side of peak EGT. Not at all
true. While there are lots of jokes about the "Church
of the Lean of Peak", there is a much greater emphasis
on how to understand the internal cylinder pressures
and resulting temperatures, than whether to run on the
rich or lean side. Where to operate is the pilot's choice.
It's obvious, though that pilots must either run far
richer that we were all taught, or get over on the lean
side, if the engine can do it smoothly. Here's where
the GAMIjectors and the state-of-the art engine monitors
come in. When the POH's were originally written this
equipment did not exist; now we have modern tools to
diagnose engines and accessories to make them run better.
Throughout the seminar, the "Preachers" made
it repeatedly clear how impressed they were with the
accuracy of the old TCM and Lycoming engine graphs.
Most of these were generated by hand calculators and
slide rules long ago, and are still precisely correct,
matching exactly with the far-better-instrumented engines
on the GAMI test stand. The respect that GAMI has for
these long-retired engineers is obvious, as the test
stand is named in honor of .
The bright and exceptionally knowledgable class participants
made the event a true graduate seminar instead of a
lecture series.. It was just great...the class was full
of very experienced pilots, all of whom contributed
real-life experiences and examples that we discussed.
My friend Ron Gatewood who came with me was a 30 year
career Marine aviator and he knows a little about airplanes...and
now flies several very sophisticated twins, in addition
to his personal Bonanza which he flew to Virginia from
his previous duty station inSouth Africa - and he teaches
multi-pilots and he was also extraordinarily impressed
with what he learned. Regardless of one's experience
a pilot is likely to benefit significantly.
I joked to one fellow student that the experienced,
high-time, and grey-haired pilots at that seminar reminded
me of the TV ad currently running for NEXIUM... wise
looking mature people saying "I didn't know"
"....didn't know"... "I didn't know"...
"I didn't..." "I didn't know" "I
didn't know".... Well, there was a helluva lot
that this pilot didn't know.
Colonel Gatewood and I had a great time playing with
my Baron on the 4:30 flight home, trying out everything
we could recall, and it all worked, too. We left Ada
and visited Glen Biggs' Chandler OK strip, but we did
not refuel... cruising thereafter at 11,000 MSL ...
so (with two takeoffs and two climbs) we made it nonstop
to Charlottesville VA. The JPI "LoFuel" alarm
went off on final... meaning that we then had one hour
left... IFR legal reserves. I would not have been able
to do that -- even from Biggs-dir-Charlottesville --
the way I set up my engines before the seminar...and
the temps stayed OK all the way...we got there only
a minute or two slower than we would have the old way.
So where is this story going and why the greatly reduced
oil consumpation? What's so different now? Two things:
this pilot knows more than he used to and his engines
now run so smooth that they can run very comfortably
lean of peak whenever he chooses, which is almost all
the time. Fuel burns are down, endurance is up, engine
cylinders run much cooler, engine EGTs are perfectly
normal, and the oil seems cleaner. There is - very strangely
- no more oil seeping out of the breathers and very
little showing up on the flaps aft of the engines. If
anyone tells you IO470s will not run smoothly lean of
peak, I'd suggest that you try to learn more. They can.
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.
We flew the Baron 280 hours in 2002 and it went in for
annual in Jan 2003. Fresh oil then, of course. No squawks
at annual, except for one slightly sticky valve so we
pulled that cylinder and replaced it. Since January
2003 we flew 95 hours. In May 2003 I was dipping the
oil and noticing that the levels were still 11 on the
right side and 10 on the left. (for some reason when
we put in 12, the dips read 13). Five months, 95 hours,
two to three quarts used? What's up, Doc?
Unbelievable. These engines are now ~200 hrs past TBO
and running like fine watches, but why the 2-3 quart
use in 95 hours? I had no idea.
I called George Braly. He laughed and said "Don't
you remember the test stand demonstration? When running
lean of peak, the peak power pulses within each cylinder
are significantly lower for the same power output than
on the rich side of the EGT curve. If the pulses are
lower, there is less blow-by past the rings. If there
is less blow-by, there will be less pressure in the
crankcase and less oil blown out the breather."
Well... I will be dipped... everything they said in
the Seminar suddenly makes even more sense. To run leaner
is to run cooler, run cheaper, run longer, even faster,
etc. They never said I'd be using oil at the rate I
am now. Both of my engines sound more like turbines
than piston engines, they just purr - there is no other
word for it. When I called Ron
Gatewood to tell him what I had observed, he responded
that the same thing happens when he runs his Chieftain
on the lean side: much less oil blown out of the crankcase,
and he had also wondered why that was.
I have wanted to put a set of on this Baron someday and several
pilots I respect greatly know that. Randy Tucker - who
maintains this Baron as my Virginia Aviation shop manager
and is a pilot himself - and Mark Hegg in Denver - another
very experienced Baron owner - after hearing this story,
both asked exactly the same thing: "You are not
going to take those engines off now, are you?"
Well, maybe not for a while, yet. As this is written,
it's February 2003 and I'll want to take engines I trust
to Alaska in July.
For me, this whole process has been a most interesting
journey of exploration and discovery. 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.
For the sequel.... Read here
what happened to the first pilot ever to read this article!!
Any questions? just give me a call, or
click on the e-mail