Fuel tank balance

Wade,

What is "LOP operations"?

Lean of Peak = LOP


I am confused now... Are you saying "running full rich" can cause
detonation? As this caused me to go look in my copy of Rod Machado's

No, I'm not. Ron Machado isn't god. He isn't even funny, mostly.

I recommend the engine management columns by John Deakin at www.avweb.com. He
explains it much better than I ever could.

--
Thomas Borchert (EDDH)

Thomas Borchert schrieb:

The only exception is the Thielert
diesel based on a modern car design, just coming to market with great
success.

Agreed, except that Thielert is not the only exception (e.g. Limbach
2400 DT1 being another example). But all those developments are pretty
recent and right now the installed base is a couple of hundred at most.

Stefan

"Thomas Borchert" wrote in message
...
Wade,

What is "LOP operations"?

Lean of Peak = LOP


I am confused now... Are you saying "running full rich" can cause
detonation? As this caused me to go look in my copy of Rod Machado's

No, I'm not. Ron Machado isn't god. He isn't even funny, mostly.

I recommend the engine management columns by John Deakin at www.avweb.com.
He
explains it much better than I ever could.

--
Thomas Borchert (EDDH)


Thanks for the Explanation of LOP... I appreciate it... I have been reading
the articles from the site that Mark pointed me to and found them a nice
resource, and something new to learn about.

If I made Rod out to be "god" that was not, that was not my intention... It
was just the book that I had available at the time, and felt it was a
sufficient reference... I just also looked in the Kershner book, and it says
pretty much the same thing as the Machado book. The Kershner book doesn't
mention anything about using EGT to lean.

As far as Rod being funny... That is purely personal taste. I enjoy his
humor, but I know others do not, and respect that, which is why when I put
the quotes from the book, I left the jokes out... :-)

But, I think Cessna is just as guilty of encouraging ROP operations as the
POH I have for a 1980 Cessna 172N says under "Cruise" procedure in Section
4, and POHs for the 172M that I fly says the same:

"To acheive the recommended lean mixture fuel consumption figures shown in
section 5, the mixture should be leaned until engine RPM peaks and drops
25-50 RPM. At lower powers it may be necessary to enrichen the mixture
slightly to obtain smooth operation."

"Should it be necessary to cruise at higher than 75% power, the mixture
should not be leaned more than is required to proved peak RPM."

Then under the subsection "Leaning with a Cessna Economy Mixture Indicator
(EGT):

"Exhaust gas temperature (EGT) as shown on the optional Cessna Economy
Mixture Indicator may be used as an aid for mixture leaning in crising
flight at 75% pwoer or less. To adjust the mixture using this indicator,
lean to establish the peak EGT as a reference point and then enrichen the
mixture by the desired increment based on figure 4-4."

Figure 4-4:
Mixture Description Exhaust Gas Temperature
Recommended Lean 50 degrees rich of Peak EGT
Best Economy Peak EGT

"Under some conditions, engine roughness may occur while operating at peak
EGT. In this case, operate at the Recommended Lean mixture. Any change in
altitude or thorttle position will require a recheck of EGT indication."

Before your post I had never heard of the term LOP operations, thus the
reason why I had asked what it was, as I had never heard of it. Most
everything that I have read, suggests ROP operation, with the exception of
Rod's book, which says when leaning via EGT it says to lean 25 - 50 degrees
LOP, which I admit I messed it up in my original post, as I probably had the
POH in my head, and since the plane I fly does not have an EGT (it was
optional 172s) I will admit that I don't do this on a regular basis.

So, I hope you can understand it was not my intent to discourage one
practice over another (I didn't really know about the one practice), I was
just giving the the information that I had at the time and the things that I
had learned from the books I have read.

Blue Skies,

Wade Hasbrouck

Mxsmanic,

You can jump without a parachute if the plane is on fire, too; the
results will be much the same, if you have no parachute training.

And again, you go on about something you are utterly clueless about.
You are wrong.


This is a key reason why parachutes are not present in civilian
aircraft. Most passengers don't have the training necessary to use
them.

No, it is not. Parachutes are not present, because they aren't needed.
In gliders, the risk of a mid-air is much higher, so they are often
issued - to untrained passengers as well. Training consists of "pull
here". It's all that's needed.

--
Thomas Borchert (EDDH)

On Mon, 25 Sep 2006 08:29:10 -0400, Ron Natalie
wrote:

Mxsmanic wrote:
Is there any reason to drain fuel tanks in any way other than
symmetrically in normal flight? I notice that most aircraft have
complex controls for fuel flow from the tanks, and I wonder if there
are things one is suppposed to do during normal flight, or if this is
just to provide for possible equipment failures or a need to shift the
center of gravity of the aircraft in an emergency.

Not all tanks can be used in all flight regimes. My tip tanks
can not be used for takeoff or landing (well I don't think they
will make a difference on landing, but you want to be able to
do a go-around don't you). Also, the injected fuel system
returns fuel back to the main tank alone in my system, so
you don't start using the aux tanks until you have sufficient
headroom in the mains.

On the Deb the tip tanks are...well...just tanks. You have to pump
the contents of the tip tanks into the mains before you can use that
gas. Of course the mains need to have enough room to take that 15
gallons each. Typically I don't bother with the tip tanks as it takes
a good 3 hour plus trip to make them useful.

When transferring fuel I run both transfer pumps at the same time to
keep things in balance. The engine burns 14 GPH. The tip tanks
carry 15 gallons each and the transfer pumps will move all 15 gallons
in 45 minutes. Running an hour on one main will make the plane
decidedly lopsided. 45 minutes is stretching the balance comfort
factor. You do not really want to burn off 15 gallons out of both
mains as there is 11 gallons considered unusable and they are 25
gallon tanks. Just to complicate matters when running off the aux
tanks (10 gallon on each side) they return to the left main only.
About 30 to 40% of the fuel ( 6 to 8 gallons) is returned to that left
main. Oh, and it feeds from both aux tanks at the same time.

As you can see, keeping in balance, keeping at least one main with
useable fuel and not over filling when transferring from the tip
tanks, or over filling the left main when running off the Aux tanks
can make keeping track of how long you are feeding from where, when
can be vital.

If I switch mains at 1/2 hour intervals, turn on the transfer pumps at
2 hours (one hour on each main) I will stay balanced and not over fill
either main. That will also leave the left main down far enough to
take the return fuel from the aux tanks without over filling OR
getting out of balance IF I continue to follow the proper sequence of
feeding.

I carry about 4 1/4 hours of useable fuel between the mains and aux
tanks. I carry about 2 hours and 10 minutes worth in the tips.

In an emergency I could use *all* of that fuel considered unusable but
I'd not want to have to do a go around or any steep climbs and all
turns would need to be right on the ball for coordination. IOW
depending on those 11 gallons would not be smart at all.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Wade,

Learning is what this is all about, so I'm glad we could point you to
something that "broadened the horizon".

. I enjoy his
humor, but I know others do not,


I used to enjoy it, but after a while, I just found it diluting the
density of information too much. But you're right: it's a matter of
taste.

--
Thomas Borchert (EDDH)

"Roger (K8RI)" wrote in message
...
In an emergency I could use *all* of that fuel considered unusable but
I'd not want to have to do a go around or any steep climbs and all
turns would need to be right on the ball for coordination. IOW
depending on those 11 gallons would not be smart at all.

So, you could basically use the 11 gallons to get you over the airport and
plan for a deadstick landing from that point... Interesting...

On Thu, 28 Sep 2006 19:03:14 GMT, "Grumman-581"
wrote:

"Roger (K8RI)" wrote in message
.. .
In an emergency I could use *all* of that fuel considered unusable but
I'd not want to have to do a go around or any steep climbs and all
turns would need to be right on the ball for coordination. IOW
depending on those 11 gallons would not be smart at all.

So, you could basically use the 11 gallons to get you over the airport and
plan for a deadstick landing from that point... Interesting...

I was thinking on having the engine quit on roll out, but one is just
a foolish as the other. :-)) The amount of adrenalin might be
different though.





Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Roger (K8RI) wrote:
I was thinking on having the engine quit on roll out, but one is just
a foolish as the other. :-)) The amount of adrenalin might be
different though.

One could argue that having the engine quit when you're 2000 ft over
the center of the runway is preferable to having it quit unexpectedly
while you're trying to fly a normal pattern and trying to get that last
drop of fuel out of the tank by making your turns "just right"... At
least you *know* what is about to happen and you don't have to consider
much in the way of alternatives...

On 28 Sep 2006 18:22:47 -0700, "Grumman-581"
wrote:

Roger (K8RI) wrote:
I was thinking on having the engine quit on roll out, but one is just
a foolish as the other. :-)) The amount of adrenalin might be
different though.

One could argue that having the engine quit when you're 2000 ft over
the center of the runway is preferable to having it quit unexpectedly

You could but I was climbing out at something like a 100 MPH and 30 to
50 feet above a 3800 foot runway.

while you're trying to fly a normal pattern and trying to get that last
drop of fuel out of the tank by making your turns "just right"... At
least you *know* what is about to happen and you don't have to consider
much in the way of alternatives...

If I ever do make such a mistake I can guarantee I'll not be flying a
normal pattern:-)) However being paranoid about fuel it's highly
unlikely I'll face such a situation unless a tank or fuel line breaks.

Oh! I forgot about the day it quit on a missed approach at roughly 400
feet. Before the instructor could holler, "Left tank Rog! LEFT TANK!"
I had already switched.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com