Fuel tank balance

"Mark Hansen" wrote in message
...
On 09/24/06 11:13, Wade Hasbrouck wrote:
"B A R R Y" wrote in message
...
On Sun, 24 Sep 2006 10:18:34 -0700, "Wade Hasbrouck"
wrote:

Service Ceiling I believe is defined as "where Vx equals Vy", which
where
they meet will result in a minimal to non-existent climb rate. Vx
increases
as altitude increases, Vy decreases as altitude increases

I always thought it was where the plane was no longer capable of
climbing at a rate greater than 100 ft/min.


You are correct... I should look at Wikipedia before typing... :-)

"From Wikipedia, the free encyclopedia

In aeronautics, the service ceiling is the density altitude where the
flying
in a clean configuration, at the best rate of climb airspeed for that
altitude, and with all engines operating and producing maximum continuous
power will produce a 100 feet per minute climb. Margin to stall at
service
ceiling is 1.5g."

Will have to go back to the reference book that talked about the point
where
Vx and Vy are equal and see what they called that... :-)


It the airplane's absolute ceiling.


I was going to say that... But figured I would go look it up before "opening
my mouth" again... :-)


--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

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

however running an
engine too lean can, because if you lean too much the cylinder head
temperatures will be higher than normal and can cause detonation.

..

No... Higher EGT indicates leaner mixture. Excess fuel in the cylinder
has
a cooling effect.

Sorry, but you're wrong. Running not lean enough can cause detonation. Or,
more exactly: Putting the mixture in the wrong place can. Cylinder
pressures
are highest at about 50 to 75 rich of peak. Higher EGT does indicate
closeness
to peak EGT, but not a leaner mixture. The leaner the mixture, the cooler
the
EGT - once you're beyond peak.

The misconceptions behind your statements lead to people not liking to
contemplate LOP operations, which is why I point them out.


--
Thomas Borchert (EDDH)


What is "LOP operations"?

I realize I got the leaning procedure for EGT wrong... As yes, you lean
until it peaks and then goes down by 25 - 50 (or what ever the POH says).
Plane I currently fly does not have an EGT and was going by what I have
read... Was taught "Lean to max RPM then richen slightly..."

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
Private Pilot Handbook to see what the causes of detonation are and he lists
the following as "several know causes of detonation"

1. Using a lower grade of fule than what is recommended by the
manufacturer. Higher octoane fuels have additives which help prevent
detonation.

2. Using time-expired fuel.

3. Over-leaning. Excessive leaning can raise cylinder head temperatures
increasing the likelihood of fuel exploding insteadd of burning within the
cylinders.

4. Overheating and engine by climbing too steeply on hotdays, as waell as
using excessive engine power (some engines have restriction on the time
maximum power can be used).

5. An abrupt opening of the throttle.

In the section "Too Rich and Too Lean" he talks about what happens if it is
too rich or too lean. The following are quotes from that section.

"Aside from inefficient fuel combustion, mixtures that are too rich or too
lean cause difficulties with engine operation. A mixture that is too rich
causes engine roughness. Spark plugs are easily fouled when unburned fuel
residue builds up between the plug gap..... "

"It's interesting to note that a fouled spark plug in flight can be detected
by an increase in EGT. Why? With only one flame source operating with the
cylinder, it takes longer to reach the maximum combustion temperature of the
cylinder's fuel-charge (it simply burns slower). As a result, the mixture
is hotter as it exits the exhaust valve, resulting in a higher EGT."

"Aside from a rough running engine, an excessively rich mixture contributes
to high fuel consumption...."

"A mixture that 's too lean produces other problems. First, too lean a
mixture means liss power is produced...."

"The biggest danger with an excessively lean mixture is that it burns hot.
It does so because it burns slower. This exposes the cylinder, postion and
valves to higher temperatures and high temperature is the worst enemy of
metal, causes reduced cylinder life and other problems..."

"High cylinder tempreatures also lead to something know as detonation.
Instead of a smoth even expansion of the fuel-air charge within the
cylinder, the mixture detonates (explodes), causing damage to the
engine...."

And there is even a question on the private pilot knowledge exam that asks
what to do if you have an overheating engine or detonation... and I believe
the the answer is "richen the mixture."

On 09/24/06 11:39, Wade Hasbrouck wrote:
"Mark Hansen" wrote in message
...
On 09/24/06 11:13, Wade Hasbrouck wrote:
"B A R R Y" wrote in message
...
On Sun, 24 Sep 2006 10:18:34 -0700, "Wade Hasbrouck"
wrote:

Service Ceiling I believe is defined as "where Vx equals Vy", which
where
they meet will result in a minimal to non-existent climb rate. Vx
increases
as altitude increases, Vy decreases as altitude increases

I always thought it was where the plane was no longer capable of
climbing at a rate greater than 100 ft/min.


You are correct... I should look at Wikipedia before typing... :-)

"From Wikipedia, the free encyclopedia

In aeronautics, the service ceiling is the density altitude where the
flying
in a clean configuration, at the best rate of climb airspeed for that
altitude, and with all engines operating and producing maximum continuous
power will produce a 100 feet per minute climb. Margin to stall at
service
ceiling is 1.5g."

Will have to go back to the reference book that talked about the point
where
Vx and Vy are equal and see what they called that... :-)


It the airplane's absolute ceiling.


I was going to say that... But figured I would go look it up before "opening
my mouth" again... :-)

Hey ... this is Usenet! ;-)

--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

Mxsmanic wrote in
:

Marty Shapiro writes:

Not too noticeable until about 8,000'. Then it gets noticeable. Above
11,000' it gets very, very noticeable. Go to Pike's Peak and see what
happens!

Yesterday I tried flying a Piper J-3 and a Cessna 172 over the top of
(I think) Mount Rainier (the tall mountain near KSEA), and they both
seemed to struggle as we approached the altitude of the peak. I
turned around and went back when it became obvious that I wasn't going
to make it. Not sure if it was engine power that lacked, or just air
density that was too low, or what. I was flying for fun and did not
check the altimeter.

Does MSFS let you set whether you have oxygen in the plane?

On 09/24/06 12:07, Wade Hasbrouck wrote:
"Thomas Borchert" wrote in message
...
Wade,

however running an
engine too lean can, because if you lean too much the cylinder head
temperatures will be higher than normal and can cause detonation.

..

No... Higher EGT indicates leaner mixture. Excess fuel in the cylinder
has
a cooling effect.

Sorry, but you're wrong. Running not lean enough can cause detonation. Or,
more exactly: Putting the mixture in the wrong place can. Cylinder
pressures
are highest at about 50 to 75 rich of peak. Higher EGT does indicate
closeness
to peak EGT, but not a leaner mixture. The leaner the mixture, the cooler
the
EGT - once you're beyond peak.

The misconceptions behind your statements lead to people not liking to
contemplate LOP operations, which is why I point them out.


--
Thomas Borchert (EDDH)


What is "LOP operations"?

Let me give you a pointer to a great deal of engine operational information.
John Deakin has written a series of articles for AVWeb. The series is
called Pelican's Perch. You can see the index of his engine-related articles
he

http://www.avweb.com/news/pelican/182544-1.html

They make a very good read. You need to be a member, but the membership
is free. If you're not familiar with AVWeb, there are lots of great
resources there, including lots of other regular columns like John's.



I realize I got the leaning procedure for EGT wrong... As yes, you lean
until it peaks and then goes down by 25 - 50 (or what ever the POH says).
Plane I currently fly does not have an EGT and was going by what I have
read... Was taught "Lean to max RPM then richen slightly..."

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
Private Pilot Handbook to see what the causes of detonation are and he lists
the following as "several know causes of detonation"

1. Using a lower grade of fule than what is recommended by the
manufacturer. Higher octoane fuels have additives which help prevent
detonation.

2. Using time-expired fuel.

3. Over-leaning. Excessive leaning can raise cylinder head temperatures
increasing the likelihood of fuel exploding insteadd of burning within the
cylinders.

4. Overheating and engine by climbing too steeply on hotdays, as waell as
using excessive engine power (some engines have restriction on the time
maximum power can be used).

5. An abrupt opening of the throttle.

In the section "Too Rich and Too Lean" he talks about what happens if it is
too rich or too lean. The following are quotes from that section.

"Aside from inefficient fuel combustion, mixtures that are too rich or too
lean cause difficulties with engine operation. A mixture that is too rich
causes engine roughness. Spark plugs are easily fouled when unburned fuel
residue builds up between the plug gap..... "

"It's interesting to note that a fouled spark plug in flight can be detected
by an increase in EGT. Why? With only one flame source operating with the
cylinder, it takes longer to reach the maximum combustion temperature of the
cylinder's fuel-charge (it simply burns slower). As a result, the mixture
is hotter as it exits the exhaust valve, resulting in a higher EGT."

"Aside from a rough running engine, an excessively rich mixture contributes
to high fuel consumption...."

"A mixture that 's too lean produces other problems. First, too lean a
mixture means liss power is produced...."

"The biggest danger with an excessively lean mixture is that it burns hot.
It does so because it burns slower. This exposes the cylinder, postion and
valves to higher temperatures and high temperature is the worst enemy of
metal, causes reduced cylinder life and other problems..."

"High cylinder tempreatures also lead to something know as detonation.
Instead of a smoth even expansion of the fuel-air charge within the
cylinder, the mixture detonates (explodes), causing damage to the
engine...."

And there is even a question on the private pilot knowledge exam that asks
what to do if you have an overheating engine or detonation... and I believe
the the answer is "richen the mixture."




--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

Mxsmanic wrote:
You'd think that the engine would be
able to measure the static air pressure and adjust the mixture for
itself. Cars have complex engine computers, so why not aircraft
engines?


There are aircraft engines that do (piston).. Look up FADEC.

But if the non FADEC engine can give similar performance with a skilled
operator, then what do you want to spend your pennies on.. a new fangled
electronically controlled engine? or keep using the old one with a few
extra knobs and dials.

Mxsmanic wrote:
new_CFI writes:


its a fule to air ratio. x:y... so as you climb and air density
decreases the amount of fule require to keep the ratio constant,
changes. So, the amout of fuel you send to the engine needs to be less.
Thats where the mixture controll comes in. If you don't have the Pilots
Handbook of Aeronautical Knowledge, there is a good explanation of
it....if you don't have it; you can download it from the faa website.
If you need the link Ill post it, but I have to run….


I have the handbook. I pretty much understand the explanation, I just
wonder why the pilot adjusts it. You'd think that the engine would be
able to measure the static air pressure and adjust the mixture for
itself. Cars have complex engine computers, so why not aircraft
engines? Of course, if aircraft engines had the same unreliable
software that they put in cars, they'd drop out of the sky, so it
would have to be verified a lot more, and the engine would have to be
able to run without it.

Some do, but most don't. My last engine had a pressure carb on it and
the only thing we used the mixture for was to shut down. The new engine
does not have a pressure carb and it took a bit for me to remember to I
have to lean now!

Margy

What is "LOP operations"?

Let me give you a pointer to a great deal of engine operational
information.
John Deakin has written a series of articles for AVWeb. The series is
called Pelican's Perch. You can see the index of his engine-related
articles
he

http://www.avweb.com/news/pelican/182544-1.html

They make a very good read. You need to be a member, but the membership
is free. If you're not familiar with AVWeb, there are lots of great
resources there, including lots of other regular columns like John's.



Thanks for the pointer to the site, I took a glance at the site... Looks
quite good. I appreciate this.



--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

Marty Shapiro wrote:

Mxsmanic wrote in
:

new_CFI writes:

the more complex adjusting of the fuel comes from the mixture control.

I don't understand the mixture control, either. Fortunately I can
have MSFS worry about that.

I'm surprised at all the fiddling that pilots are expected to do with
their propulsion units, as compared to other types of vehicles. Bad
enough that one must know how to fly, but apparently one must be a
qualified engine mechanic as well.


Have you ever driven a non-turbocharged car from a low lying city up into
the mountains, like above 5,000' MSL? If you did, you would understand why
the pilot has to manipulate the mixture.

Yes, except I've gone far higher than 5,000' MSL. Take a morning drive from
any (sea level) beach in Maui, for example to the summit of Mt Haleakala
(10,000+ ft). And the 'pilot' of the car doesn't have to do a damn thing for
the mixture, the injector pulse width (aka the mixture) is adjusted by the
computer automatically for max performance of power/emissions. Pretty basic
stuff for any car today, too bad so many aircraft are still using 1930s era
design engines.

Marty Shapiro wrote:

Mxsmanic wrote in
:

new_CFI writes:

the more complex adjusting of the fuel comes from the mixture control.

I don't understand the mixture control, either. Fortunately I can
have MSFS worry about that.

I'm surprised at all the fiddling that pilots are expected to do with
their propulsion units, as compared to other types of vehicles. Bad
enough that one must know how to fly, but apparently one must be a
qualified engine mechanic as well.


Have you ever driven a non-turbocharged car from a low lying city up into
the mountains, like above 5,000' MSL? If you did, you would understand why
the pilot has to manipulate the mixture.

Also, the design of the aircraft engine is such that once it is started,
the engine driven magnetos provide the spark to keep it running.

Yes, doens't that remind you of a basic lawn mower engine?

You can
have total electrical failure and the engine will keep on running.

They may not be connected to the battery or alternator, but those magnetos are
an "electrical system" all of their own, and the engine will not keep running
if they have an electrical failure.

How do you stop the engine after you land?

Disconnecting the magnetos (or actually just grounding their output) stops the
engine pretty well. No need for a mixture control. (Of course if you want to
restart that engine without blowing away the exhaust......)