Went flying this weekend and had some fuel management issues that
I still don't totally understand, so thought I would share with
the group, as it might affect you one day, too.
Usually in the winter, I transition from mogas to avgas, and was
last flying with one tank avgas and using up the last of the
mogas in the other. Anyway, I didn't get it quite empty on my
previous flight, so decided to drain the last of it (only 2 gal
left) through my gascolator, so I could fill up that tank, too,
with pure avgas.
While draining the mogas tank, I, of course, closed the other
avgas tank fuel valve. When finished, I closed the empty tank
valve and opened the other avgas tank again, and started the
engine to go fuel up my empty tank at the pumps. The engine
started fine, and I began my taxi. Well, I barely got going when
the engine quit. And I could not start it, no matter what. It
fired up a couple of times, but would not continue running. I
then opened up the closed empty tank, and after a short wait
(maybe 20 seconds) I then started and was able to continue on to
the fuel pump without further interruption.
This has actually happened to me before, while still on the
ground, with similar circumstances after draining a tank, but
wasn't exactly sure if it was a fluke or what. The fact that it
happened again, makes me very leery of ever running one tank dry
in the air. The tank that I switched to had exactly 15 US g, so
it wasn't anywhere near empty. What was interesting is that I
couldn't get the engine started until I opened the other empty
tank. So my theory is, it allowed the air to escape up there, and
then the fuel was able to flow freely from the full tank. My
tanks are plumbed so that the shut off valves are up top at the
tank outlets, and the lines are not tee'd together until just
before the gascolator on the firewall. I also have a fuel flow
sender that is on the output of the gascolator, that I believe
costs at most 0.5 PSI to operate. No fuel pumps, just gravity
feed.
Anyway, I think I have heard Bob P say, and maybe others that
they have run one tank dry in the air, and no problem. So my
question is, how exactly did you do that and exactly how low was
the fuel in the new tank? As I said, mine was 15 g, and it still
didn't start. When you opened the good tank, did you first close
the empty tank, or was it still open? I am just wondering what is
the better procedure. From my ground experience, it would seem
that it is better to leave the empty tank open until the engine
is running fine on the new tank.
I often fly with one tank, and switch tanks in flight, but have
never run one dry. When I do get low in one tank, as I did in my
previous flight (only 2 gal left) I switch to both before
landing, or when I am not over water. So I would like to
understand this better before I try running one tank completely
dry.
OK, that was one fuel issue. On the same day, when I took off,
after fuelling, I had another, that may or may not be related.
Here is what happened. I did my run-up, with both tanks now open,
and proceeded to the runway, but had to hold about 5 minutes
while other planes landed, and another ahead of me waited his
turn also. It's not normally that busy here, but it was a rare
nice day, and of course everybody decided to go flying. Anyway,
right after take-off, I noticed my rpm fluctuate and drop to low
2400's and even into the 2300's for a couple of seconds. I didn't
notice that it ran rough, just not full power. I climbed to about
300 feet and then abandoned our noise abatement path and started
a left turn so I could catch the crosswind grass runway if I had
to. It continued to climb though, and then resumed its usual
climb rpm of 2550, and ran just fine after that. The rest of my
flying that day was uneventful, but needless to say, I wasn't
happy with what happened.
I have a couple of theories on this last issue. One is that I
still may have had some air in my lines after bringing the second
tank online after fuelling. My run-ups are only at 1800 rpm
because of my amphib brakes. The other is that I may have got
some carb ice after sitting at idle so long waiting for my turn
to take off. OAT on the ground at that time was about 5 C (40F).
Or maybe my plugs fouled up a bit with lead with the long idle.
Any thoughts? I don't like mysteries of this kind.
Walter
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Rebel Fuel Management
-
Wayne G. O'Shea
Rebel Fuel Management
Walter...Yes you filled your fuel line and gascolator with air..as you took
all the fuel out! When you tried to start on the filled tank it started on
the fuel in the carb and then there was nothing but air left in the system.
Turning on the empty tank let the fuel refill that line back up to the tank
and pushed that air out...probably leaving the gascolator slightly air
filled. A combination of bubbles making it both ways..back to tank and into
carb would have happened after you got it running successfully. I would
suspect that when you were under full power taking off the last of the air
bubbles went forward thanks to the high fuel flow and nose up attitude.
Next time you do this ritual...feed the engine slowly by using the
primer.... to suck the last of the air off the top of the gascolator.
I never run a tank dry..if one tank is almost empty I shut that side off if
I need to balance and use the greater filled tank up until it is close to
the other...then switch to both..say a prayer and hope I have enough fumes
to make destination!
)
Wayne
----- Original Message -----
From: "Walter Klatt" <Walter.Klatt@shaw.ca>
To: "Rebel-Builders" <rebel-builders@dcsol.com>
Sent: Monday, December 13, 2004 8:22 PM
Subject: Rebel Fuel Management
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all the fuel out! When you tried to start on the filled tank it started on
the fuel in the carb and then there was nothing but air left in the system.
Turning on the empty tank let the fuel refill that line back up to the tank
and pushed that air out...probably leaving the gascolator slightly air
filled. A combination of bubbles making it both ways..back to tank and into
carb would have happened after you got it running successfully. I would
suspect that when you were under full power taking off the last of the air
bubbles went forward thanks to the high fuel flow and nose up attitude.
Next time you do this ritual...feed the engine slowly by using the
primer.... to suck the last of the air off the top of the gascolator.
I never run a tank dry..if one tank is almost empty I shut that side off if
I need to balance and use the greater filled tank up until it is close to
the other...then switch to both..say a prayer and hope I have enough fumes
to make destination!
)Wayne
----- Original Message -----
From: "Walter Klatt" <Walter.Klatt@shaw.ca>
To: "Rebel-Builders" <rebel-builders@dcsol.com>
Sent: Monday, December 13, 2004 8:22 PM
Subject: Rebel Fuel Management
Went flying this weekend and had some fuel management issues that
I still don't totally understand, so thought I would share with
the group, as it might affect you one day, too.
Usually in the winter, I transition from mogas to avgas, and was
last flying with one tank avgas and using up the last of the
mogas in the other. Anyway, I didn't get it quite empty on my
previous flight, so decided to drain the last of it (only 2 gal
left) through my gascolator, so I could fill up that tank, too,
with pure avgas.
While draining the mogas tank, I, of course, closed the other
avgas tank fuel valve. When finished, I closed the empty tank
valve and opened the other avgas tank again, and started the
engine to go fuel up my empty tank at the pumps. The engine
started fine, and I began my taxi. Well, I barely got going when
the engine quit. And I could not start it, no matter what. It
fired up a couple of times, but would not continue running. I
then opened up the closed empty tank, and after a short wait
(maybe 20 seconds) I then started and was able to continue on to
the fuel pump without further interruption.
This has actually happened to me before, while still on the
ground, with similar circumstances after draining a tank, but
wasn't exactly sure if it was a fluke or what. The fact that it
happened again, makes me very leery of ever running one tank dry
in the air. The tank that I switched to had exactly 15 US g, so
it wasn't anywhere near empty. What was interesting is that I
couldn't get the engine started until I opened the other empty
tank. So my theory is, it allowed the air to escape up there, and
then the fuel was able to flow freely from the full tank. My
tanks are plumbed so that the shut off valves are up top at the
tank outlets, and the lines are not tee'd together until just
before the gascolator on the firewall. I also have a fuel flow
sender that is on the output of the gascolator, that I believe
costs at most 0.5 PSI to operate. No fuel pumps, just gravity
feed.
Anyway, I think I have heard Bob P say, and maybe others that
they have run one tank dry in the air, and no problem. So my
question is, how exactly did you do that and exactly how low was
the fuel in the new tank? As I said, mine was 15 g, and it still
didn't start. When you opened the good tank, did you first close
the empty tank, or was it still open? I am just wondering what is
the better procedure. From my ground experience, it would seem
that it is better to leave the empty tank open until the engine
is running fine on the new tank.
I often fly with one tank, and switch tanks in flight, but have
never run one dry. When I do get low in one tank, as I did in my
previous flight (only 2 gal left) I switch to both before
landing, or when I am not over water. So I would like to
understand this better before I try running one tank completely
dry.
OK, that was one fuel issue. On the same day, when I took off,
after fuelling, I had another, that may or may not be related.
Here is what happened. I did my run-up, with both tanks now open,
and proceeded to the runway, but had to hold about 5 minutes
while other planes landed, and another ahead of me waited his
turn also. It's not normally that busy here, but it was a rare
nice day, and of course everybody decided to go flying. Anyway,
right after take-off, I noticed my rpm fluctuate and drop to low
2400's and even into the 2300's for a couple of seconds. I didn't
notice that it ran rough, just not full power. I climbed to about
300 feet and then abandoned our noise abatement path and started
a left turn so I could catch the crosswind grass runway if I had
to. It continued to climb though, and then resumed its usual
climb rpm of 2550, and ran just fine after that. The rest of my
flying that day was uneventful, but needless to say, I wasn't
happy with what happened.
I have a couple of theories on this last issue. One is that I
still may have had some air in my lines after bringing the second
tank online after fuelling. My run-ups are only at 1800 rpm
because of my amphib brakes. The other is that I may have got
some carb ice after sitting at idle so long waiting for my turn
to take off. OAT on the ground at that time was about 5 C (40F).
Or maybe my plugs fouled up a bit with lead with the long idle.
Any thoughts? I don't like mysteries of this kind.
Walter
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-
Ted I Weitz
Rebel Fuel Management
Hi,
I kind of like the air in the lines theory for both issues. I thought of
some closed vent possibility but that doesn't seem likely if you have run
this tank open while the other is close before.
As for the Gravity Theory, always doubted it.
I like the electric fuel pump theory better, as I learned in boot camp:
What doesn't go with force, goes with more force... :)
Ted
----- Original Message -----
From: "Walter Klatt" <Walter.Klatt@shaw.ca>
To: "Rebel-Builders" <rebel-builders@dcsol.com>
Sent: Monday, December 13, 2004 8:22 PM
Subject: Rebel Fuel Management
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-----------------------------------------------------------------
I kind of like the air in the lines theory for both issues. I thought of
some closed vent possibility but that doesn't seem likely if you have run
this tank open while the other is close before.
As for the Gravity Theory, always doubted it.
I like the electric fuel pump theory better, as I learned in boot camp:
What doesn't go with force, goes with more force... :)
Ted
----- Original Message -----
From: "Walter Klatt" <Walter.Klatt@shaw.ca>
To: "Rebel-Builders" <rebel-builders@dcsol.com>
Sent: Monday, December 13, 2004 8:22 PM
Subject: Rebel Fuel Management
Went flying this weekend and had some fuel management issues that
I still don't totally understand, so thought I would share with
the group, as it might affect you one day, too.
Usually in the winter, I transition from mogas to avgas, and was
last flying with one tank avgas and using up the last of the
mogas in the other. Anyway, I didn't get it quite empty on my
previous flight, so decided to drain the last of it (only 2 gal
left) through my gascolator, so I could fill up that tank, too,
with pure avgas.
While draining the mogas tank, I, of course, closed the other
avgas tank fuel valve. When finished, I closed the empty tank
valve and opened the other avgas tank again, and started the
engine to go fuel up my empty tank at the pumps. The engine
started fine, and I began my taxi. Well, I barely got going when
the engine quit. And I could not start it, no matter what. It
fired up a couple of times, but would not continue running. I
then opened up the closed empty tank, and after a short wait
(maybe 20 seconds) I then started and was able to continue on to
the fuel pump without further interruption.
This has actually happened to me before, while still on the
ground, with similar circumstances after draining a tank, but
wasn't exactly sure if it was a fluke or what. The fact that it
happened again, makes me very leery of ever running one tank dry
in the air. The tank that I switched to had exactly 15 US g, so
it wasn't anywhere near empty. What was interesting is that I
couldn't get the engine started until I opened the other empty
tank. So my theory is, it allowed the air to escape up there, and
then the fuel was able to flow freely from the full tank. My
tanks are plumbed so that the shut off valves are up top at the
tank outlets, and the lines are not tee'd together until just
before the gascolator on the firewall. I also have a fuel flow
sender that is on the output of the gascolator, that I believe
costs at most 0.5 PSI to operate. No fuel pumps, just gravity
feed.
Anyway, I think I have heard Bob P say, and maybe others that
they have run one tank dry in the air, and no problem. So my
question is, how exactly did you do that and exactly how low was
the fuel in the new tank? As I said, mine was 15 g, and it still
didn't start. When you opened the good tank, did you first close
the empty tank, or was it still open? I am just wondering what is
the better procedure. From my ground experience, it would seem
that it is better to leave the empty tank open until the engine
is running fine on the new tank.
I often fly with one tank, and switch tanks in flight, but have
never run one dry. When I do get low in one tank, as I did in my
previous flight (only 2 gal left) I switch to both before
landing, or when I am not over water. So I would like to
understand this better before I try running one tank completely
dry.
OK, that was one fuel issue. On the same day, when I took off,
after fuelling, I had another, that may or may not be related.
Here is what happened. I did my run-up, with both tanks now open,
and proceeded to the runway, but had to hold about 5 minutes
while other planes landed, and another ahead of me waited his
turn also. It's not normally that busy here, but it was a rare
nice day, and of course everybody decided to go flying. Anyway,
right after take-off, I noticed my rpm fluctuate and drop to low
2400's and even into the 2300's for a couple of seconds. I didn't
notice that it ran rough, just not full power. I climbed to about
300 feet and then abandoned our noise abatement path and started
a left turn so I could catch the crosswind grass runway if I had
to. It continued to climb though, and then resumed its usual
climb rpm of 2550, and ran just fine after that. The rest of my
flying that day was uneventful, but needless to say, I wasn't
happy with what happened.
I have a couple of theories on this last issue. One is that I
still may have had some air in my lines after bringing the second
tank online after fuelling. My run-ups are only at 1800 rpm
because of my amphib brakes. The other is that I may have got
some carb ice after sitting at idle so long waiting for my turn
to take off. OAT on the ground at that time was about 5 C (40F).
Or maybe my plugs fouled up a bit with lead with the long idle.
Any thoughts? I don't like mysteries of this kind.
Walter
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-
Wayne G. O'Shea
Rebel Fuel Management
What'a ya mean Ted...if the engine quits the gravity theory definitely takes
over !)
----- Original Message -----
From: "Ted I Weitz" <me@tedweitz.com>
To: <rebel-builders@dcsol.com>
Sent: Monday, December 13, 2004 8:56 PM
Subject: Re: Rebel Fuel Management
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over !
)----- Original Message -----
From: "Ted I Weitz" <me@tedweitz.com>
To: <rebel-builders@dcsol.com>
Sent: Monday, December 13, 2004 8:56 PM
Subject: Re: Rebel Fuel Management
Hi,
I kind of like the air in the lines theory for both issues. I thought of
some closed vent possibility but that doesn't seem likely if you have run
this tank open while the other is close before.
As for the Gravity Theory, always doubted it.
I like the electric fuel pump theory better, as I learned in boot camp:
What doesn't go with force, goes with more force... :)
Ted
----- Original Message -----
From: "Walter Klatt" <Walter.Klatt@shaw.ca>
To: "Rebel-Builders" <rebel-builders@dcsol.com>
Sent: Monday, December 13, 2004 8:22 PM
Subject: Rebel Fuel Management
Went flying this weekend and had some fuel management issues that
I still don't totally understand, so thought I would share with
the group, as it might affect you one day, too.
Usually in the winter, I transition from mogas to avgas, and was
last flying with one tank avgas and using up the last of the
mogas in the other. Anyway, I didn't get it quite empty on my
previous flight, so decided to drain the last of it (only 2 gal
left) through my gascolator, so I could fill up that tank, too,
with pure avgas.
While draining the mogas tank, I, of course, closed the other
avgas tank fuel valve. When finished, I closed the empty tank
valve and opened the other avgas tank again, and started the
engine to go fuel up my empty tank at the pumps. The engine
started fine, and I began my taxi. Well, I barely got going when
the engine quit. And I could not start it, no matter what. It
fired up a couple of times, but would not continue running. I
then opened up the closed empty tank, and after a short wait
(maybe 20 seconds) I then started and was able to continue on to
the fuel pump without further interruption.
This has actually happened to me before, while still on the
ground, with similar circumstances after draining a tank, but
wasn't exactly sure if it was a fluke or what. The fact that it
happened again, makes me very leery of ever running one tank dry
in the air. The tank that I switched to had exactly 15 US g, so
it wasn't anywhere near empty. What was interesting is that I
couldn't get the engine started until I opened the other empty
tank. So my theory is, it allowed the air to escape up there, and
then the fuel was able to flow freely from the full tank. My
tanks are plumbed so that the shut off valves are up top at the
tank outlets, and the lines are not tee'd together until just
before the gascolator on the firewall. I also have a fuel flow
sender that is on the output of the gascolator, that I believe
costs at most 0.5 PSI to operate. No fuel pumps, just gravity
feed.
Anyway, I think I have heard Bob P say, and maybe others that
they have run one tank dry in the air, and no problem. So my
question is, how exactly did you do that and exactly how low was
the fuel in the new tank? As I said, mine was 15 g, and it still
didn't start. When you opened the good tank, did you first close
the empty tank, or was it still open? I am just wondering what is
the better procedure. From my ground experience, it would seem
that it is better to leave the empty tank open until the engine
is running fine on the new tank.
I often fly with one tank, and switch tanks in flight, but have
never run one dry. When I do get low in one tank, as I did in my
previous flight (only 2 gal left) I switch to both before
landing, or when I am not over water. So I would like to
understand this better before I try running one tank completely
dry.
OK, that was one fuel issue. On the same day, when I took off,
after fuelling, I had another, that may or may not be related.
Here is what happened. I did my run-up, with both tanks now open,
and proceeded to the runway, but had to hold about 5 minutes
while other planes landed, and another ahead of me waited his
turn also. It's not normally that busy here, but it was a rare
nice day, and of course everybody decided to go flying. Anyway,
right after take-off, I noticed my rpm fluctuate and drop to low
2400's and even into the 2300's for a couple of seconds. I didn't
notice that it ran rough, just not full power. I climbed to about
300 feet and then abandoned our noise abatement path and started
a left turn so I could catch the crosswind grass runway if I had
to. It continued to climb though, and then resumed its usual
climb rpm of 2550, and ran just fine after that. The rest of my
flying that day was uneventful, but needless to say, I wasn't
happy with what happened.
I have a couple of theories on this last issue. One is that I
still may have had some air in my lines after bringing the second
tank online after fuelling. My run-ups are only at 1800 rpm
because of my amphib brakes. The other is that I may have got
some carb ice after sitting at idle so long waiting for my turn
to take off. OAT on the ground at that time was about 5 C (40F).
Or maybe my plugs fouled up a bit with lead with the long idle.
Any thoughts? I don't like mysteries of this kind.
Walter
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-
Legeorgen
Rebel Fuel Management
Hi Walter,
How is the avgas tank vented? Maybe it was plugged. Or, Like you said, there
may have been some air trapped between the avgas flowing in and the carb. An
electric fuel pump would have been nice to use if you have one.
It would make sense to open the full tank right before the low tank is run
dry, so you don't trap air, if that is what's happening.
Do you lean when you,re idling to prevent lead fouling?
I would check the gascolator screen, maybe it is dirty from running the one
tank dry.
Bruce
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How is the avgas tank vented? Maybe it was plugged. Or, Like you said, there
may have been some air trapped between the avgas flowing in and the carb. An
electric fuel pump would have been nice to use if you have one.
It would make sense to open the full tank right before the low tank is run
dry, so you don't trap air, if that is what's happening.
Do you lean when you,re idling to prevent lead fouling?
I would check the gascolator screen, maybe it is dirty from running the one
tank dry.
Bruce
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-
Walter Klatt
Rebel Fuel Management
Both caps have forward facing tube vents, and the tanks are
connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
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connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
-----Original Message-----
From: mike.davis@dcsol.com
[mailto:mike.davis@dcsol.com]On Behalf Of
Legeorgen@aol.com
Sent: Monday, December 13, 2004 8:08 PM
To: rebel-builders@dcsol.com
Subject: Re: Rebel Fuel Management
Hi Walter,
How is the avgas tank vented? Maybe it was plugged.
Or, Like you said, there
may have been some air trapped between the avgas
flowing in and the carb. An
electric fuel pump would have been nice to use if you
have one.
It would make sense to open the full tank right before
the low tank is run
dry, so you don't trap air, if that is what's happening.
Do you lean when you,re idling to prevent lead fouling?
I would check the gascolator screen, maybe it is dirty
from running the one
tank dry.
Bruce
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sedanman88
Rebel Fuel Management
Walter
Just some food for thought on the possibility of carb
ice ref. your second problem.
http://www.experimental-aviation.com/carb_ice.html
Just some food for thought on the possibility of carb
ice ref. your second problem.
http://www.experimental-aviation.com/carb_ice.html
-
Drew Dalgleish
Rebel Fuel Management
At 08:41 PM 12/13/2004 -0800, you wrote:
countries when I'm getting near maximun range for the fuel carried. I feel
better having all my remaining fuel in one tank rather than split between 2
just because I've also had the problem of unporting the intake pipe with
low fuel when cranking and banking close to the ground. My vent is at the
wing root on the pilots side and that tank seems to feed a little faster
than the other one. so it's easier to manage just one tank at a time.
Drew
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Hi Walter I've run one tank dry in flight a few times on long crossBoth caps have forward facing tube vents, and the tanks are
connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
countries when I'm getting near maximun range for the fuel carried. I feel
better having all my remaining fuel in one tank rather than split between 2
just because I've also had the problem of unporting the intake pipe with
low fuel when cranking and banking close to the ground. My vent is at the
wing root on the pilots side and that tank seems to feed a little faster
than the other one. so it's easier to manage just one tank at a time.
Drew
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Reed Britt Civ OO-ALC/MAD
Rebel Fuel Management
Check out this article on AVWeb - Suggests to run the tanks dry so you know
where you stand - Not that I have ever done it but it seems reasonable -
What if it happens accidentally? Will it restart?
http://www.avweb.com/news/columns/182044-1.html
Britt - SR194
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Drew
Dalgleish
Sent: Tuesday, December 14, 2004 8:27 AM
To: rebel-builders@dcsol.com
Subject: RE: Rebel Fuel Management
At 08:41 PM 12/13/2004 -0800, you wrote:
countries when I'm getting near maximun range for the fuel carried. I feel
better having all my remaining fuel in one tank rather than split between 2
just because I've also had the problem of unporting the intake pipe with
low fuel when cranking and banking close to the ground. My vent is at the
wing root on the pilots side and that tank seems to feed a little faster
than the other one. so it's easier to manage just one tank at a time.
Drew
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where you stand - Not that I have ever done it but it seems reasonable -
What if it happens accidentally? Will it restart?
http://www.avweb.com/news/columns/182044-1.html
Britt - SR194
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Drew
Dalgleish
Sent: Tuesday, December 14, 2004 8:27 AM
To: rebel-builders@dcsol.com
Subject: RE: Rebel Fuel Management
At 08:41 PM 12/13/2004 -0800, you wrote:
Hi Walter I've run one tank dry in flight a few times on long crossBoth caps have forward facing tube vents, and the tanks are
connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
countries when I'm getting near maximun range for the fuel carried. I feel
better having all my remaining fuel in one tank rather than split between 2
just because I've also had the problem of unporting the intake pipe with
low fuel when cranking and banking close to the ground. My vent is at the
wing root on the pilots side and that tank seems to feed a little faster
than the other one. so it's easier to manage just one tank at a time.
Drew
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WALTER KLATT
Rebel Fuel Management
Drew, can you give me a couple more specifics about your fuel system. Do you have the standard MAM shut-off valves up top at the tank outlets? Where are the lines tee'd together?
And when you run a tank dry, exactly what order do you open and close the valves? Do you first close the empty tank and then open the full one? Or do you open the full one first, and close the empty one after the engine starts up again?
Walter
----- Original Message -----
From: Drew Dalgleish <drewjan@cabletv.on.ca>
Date: Tuesday, December 14, 2004 7:26 am
Subject: RE: Rebel Fuel Management
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And when you run a tank dry, exactly what order do you open and close the valves? Do you first close the empty tank and then open the full one? Or do you open the full one first, and close the empty one after the engine starts up again?
Walter
----- Original Message -----
From: Drew Dalgleish <drewjan@cabletv.on.ca>
Date: Tuesday, December 14, 2004 7:26 am
Subject: RE: Rebel Fuel Management
At 08:41 PM 12/13/2004 -0800, you wrote:Hi Walter I've run one tank dry in flight a few times on long crossBoth caps have forward facing tube vents, and the tanks are
connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
countries when I'm getting near maximun range for the fuel
carried. I feel
better having all my remaining fuel in one tank rather than split
between 2
just because I've also had the problem of unporting the intake
pipe with
low fuel when cranking and banking close to the ground. My vent is
at the
wing root on the pilots side and that tank seems to feed a little
fasterthan the other one. so it's easier to manage just one tank
at a time.
Drew
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WALTER KLATT
Rebel Fuel Management
I agree with the article, but in my case I don't see the point of trying it in the air when I know it doesn't work on the ground. I am just puzzled how others get away with it. I have some theories, but would like to gather a few more facts from Drew and others who have successfully done it.
Walter
----- Original Message -----
From: Reed Britt Civ OO-ALC/MADE <Britt.REED@HILL.af.mil>
Date: Tuesday, December 14, 2004 7:41 am
Subject: RE: Rebel Fuel Management
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Walter
----- Original Message -----
From: Reed Britt Civ OO-ALC/MADE <Britt.REED@HILL.af.mil>
Date: Tuesday, December 14, 2004 7:41 am
Subject: RE: Rebel Fuel Management
Check out this article on AVWeb - Suggests to run the tanks dry so
you know
where you stand - Not that I have ever done it but it seems
reasonable -
What if it happens accidentally? Will it restart?
http://www.avweb.com/news/columns/182044-1.html
Britt - SR194
-----Original Message-----
From: mike.davis@dcsol.com [mike.davis@dcsol.com] On Behalf Of Drew
Dalgleish
Sent: Tuesday, December 14, 2004 8:27 AM
To: rebel-builders@dcsol.com
Subject: RE: Rebel Fuel Management
At 08:41 PM 12/13/2004 -0800, you wrote:Hi Walter I've run one tank dry in flight a few times on long crossBoth caps have forward facing tube vents, and the tanks are
connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
countries when I'm getting near maximun range for the fuel
carried. I feel
better having all my remaining fuel in one tank rather than split
between 2
just because I've also had the problem of unporting the intake
pipe with
low fuel when cranking and banking close to the ground. My vent is
at the
wing root on the pilots side and that tank seems to feed a little
fasterthan the other one. so it's easier to manage just one tank
at a time.
Drew
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George Coy
Rebel Fuel Management
In the good OLD days we were taught the same thing, Run one tank dry and you
know how much is in the other.
That worked for carburetor engines with a float bowl that gave some warning
before it quit stone cold. With injected engines (M14P is an injected
engine) the process may not be so safe. If you get a slug of air in the
line, the pump may cavitate for a bit before it picks up again (if it does
at all). It is not good for your heart health!
Injected engines will quit just like you turned off the mag switch. If your
fuel system has a vapor return system, then things are a little better, as
the fuel pump has a place to put the air in the line besides through the
injector system. That is why I advocate a vapor return system with the M14P
engines (IO540 as well).
George Coy
President
Gesoco Industries Inc.
629 Airport Rd.
Swanton, VT 05488
TEL 802-868-5633
FAX 802-868-4465
Web Site www.gesoco.com
e-mail George@gesoco.com
Franklin County Airport (KFSO)
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
WALTER KLATT
Sent: Tuesday, December 14, 2004 11:50 AM
To: rebel-builders@dcsol.com
Subject: Re: RE: Rebel Fuel Management
I agree with the article, but in my case I don't see the point of trying it
in the air when I know it doesn't work on the ground. I am just puzzled how
others get away with it. I have some theories, but would like to gather a
few more facts from Drew and others who have successfully done it.
Walter
----- Original Message -----
From: Reed Britt Civ OO-ALC/MADE <Britt.REED@HILL.af.mil>
Date: Tuesday, December 14, 2004 7:41 am
Subject: RE: Rebel Fuel Management
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know how much is in the other.
That worked for carburetor engines with a float bowl that gave some warning
before it quit stone cold. With injected engines (M14P is an injected
engine) the process may not be so safe. If you get a slug of air in the
line, the pump may cavitate for a bit before it picks up again (if it does
at all). It is not good for your heart health!
Injected engines will quit just like you turned off the mag switch. If your
fuel system has a vapor return system, then things are a little better, as
the fuel pump has a place to put the air in the line besides through the
injector system. That is why I advocate a vapor return system with the M14P
engines (IO540 as well).
George Coy
President
Gesoco Industries Inc.
629 Airport Rd.
Swanton, VT 05488
TEL 802-868-5633
FAX 802-868-4465
Web Site www.gesoco.com
e-mail George@gesoco.com
Franklin County Airport (KFSO)
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
WALTER KLATT
Sent: Tuesday, December 14, 2004 11:50 AM
To: rebel-builders@dcsol.com
Subject: Re: RE: Rebel Fuel Management
I agree with the article, but in my case I don't see the point of trying it
in the air when I know it doesn't work on the ground. I am just puzzled how
others get away with it. I have some theories, but would like to gather a
few more facts from Drew and others who have successfully done it.
Walter
----- Original Message -----
From: Reed Britt Civ OO-ALC/MADE <Britt.REED@HILL.af.mil>
Date: Tuesday, December 14, 2004 7:41 am
Subject: RE: Rebel Fuel Management
Check out this article on AVWeb - Suggests to run the tanks dry so
you know
where you stand - Not that I have ever done it but it seems
reasonable -
What if it happens accidentally? Will it restart?
http://www.avweb.com/news/columns/182044-1.html
Britt - SR194
-----Original Message-----
From: mike.davis@dcsol.com [mike.davis@dcsol.com] On Behalf Of Drew
Dalgleish
Sent: Tuesday, December 14, 2004 8:27 AM
To: rebel-builders@dcsol.com
Subject: RE: Rebel Fuel Management
At 08:41 PM 12/13/2004 -0800, you wrote:Hi Walter I've run one tank dry in flight a few times on long crossBoth caps have forward facing tube vents, and the tanks are
connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
countries when I'm getting near maximun range for the fuel
carried. I feel
better having all my remaining fuel in one tank rather than split
between 2
just because I've also had the problem of unporting the intake
pipe with
low fuel when cranking and banking close to the ground. My vent is
at the
wing root on the pilots side and that tank seems to feed a little
fasterthan the other one. so it's easier to manage just one tank
at a time.
Drew
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bosdes
Rebel Fuel Management
I took the Champ up one fine day in Winter a couple of years ago. I landed at Hampton (grass field) and when I left about a half hour later, I had to wait awhile before the runway was clear for takeoff. There was a lot of ice in the taxi area, so while I waited I ran around 1200 RPM, and because of the ice I didn't do a runup. I barely cleared the trees (lucky for me the air was cold), and as I limped around the pattern tried carb heat to no avail. But it was carb ice. Ten minutes on the ground and the radiant heat from the engine melted the ice. I taxied with carb heat to takeoff, and had no problems that time.
-------------- Original message from Walter Klatt <Walter.Klatt@shaw.ca>: --------------
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-------------- Original message from Walter Klatt <Walter.Klatt@shaw.ca>: --------------
Went flying this weekend and had some fuel management issues that
I still don't totally understand, so thought I would share with
the group, as it might affect you one day, too.
Usually in the winter, I transition from mogas to avgas, and was
last flying with one tank avgas and using up the last of the
mogas in the other. Anyway, I didn't get it quite empty on my
previous flight, so decided to drain the last of it (only 2 gal
left) through my gascolator, so I could fill up that tank, too,
with pure avgas.
While draining the mogas tank, I, of course, closed the other
avgas tank fuel valve. When finished, I closed the empty tank
valve and opened the other avgas tank again, and started the
engine to go fuel up my empty tank at the pumps. The engine
started fine, and I began my taxi. Well, I barely got going when
the engine quit. And I could not start it, no matter what. It
fired up a couple of times, but would not continue running. I
then opened up the closed empty tank, and after a short wait
(maybe 20 seconds) I then started and was able to continue on to
the fuel pump without further interruption.
This has actually happened to me before, while still on the
ground, with similar circumstances after draining a tank, but
wasn't exactly sure if it was a fluke or what. The fact that it
happened again, makes me very leery of ever running one tank dry
in the air. The tank that I switched to had exactly 15 US g, so
it wasn't anywhere near empty. What was interesting is that I
couldn't get the engine started until I opened the other empty
tank. So my theory is, it allowed the air to escape up there, and
then the fuel was able to flow freely from the full tank. My
tanks are plumbed so that the shut off valves are up top at the
tank outlets, and the lines are not tee'd together until just
before the gascolator on the firewall. I also have a fuel flow
sender that is on the output of the gascolator, that I believe
costs at most 0.5 PSI to operate. No fuel pumps, just gravity
feed.
Anyway, I think I have heard Bob P say, and maybe others that
they have run one tank dry in the air, and no problem. So my
question is, how exactly did you do that and exactly how low was
the fuel in the new tank? As I said, mine was 15 g, and it still
didn't start. When you opened the good tank, did you first close
the empty tank, or was it still open? I am just wondering what is
the better procedure. From my ground experience, it would seem
that it is better to leave the empty tank open until the engine
is running fine on the new tank.
I often fly with one tank, and switch tanks in flight, but have
never run one dry. When I do get low in one tank, as I did in my
previous flight (only 2 gal left) I switch to both before
landing, or when I am not over water. So I would like to
understand this better before I try running one tank completely
dry.
OK, that was one fuel issue. On the same day, when I took off,
after fuelling, I had another, that may or may not be related.
Here is what happened. I did my run-up, with both tanks now open,
and proceeded to the runway, but had to hold about 5 minutes
while other planes landed, and another ahead of me waited his
turn also. It's not normally that busy here, but it was a rare
nice day, and of course everybody decided to go flying. Anyway,
right after take-off, I noticed my rpm fluctuate and drop to low
2400's and even into the 2300's for a couple of seconds. I didn't
notice that it ran rough, just not full power. I climbed to about
300 feet and then abandoned our noise abatement path and started
a left turn so I could catch the crosswind grass runway if I had
to. It continued to climb though, and then resumed its usual
climb rpm of 2550, and ran just fine after that. The rest of my
flying that day was uneventful, but needless to say, I wasn't
happy with what happened.
I have a couple of theories on this last issue. One is that I
still may have had some air in my lines after bringing the second
tank online after fuelling. My run-ups are only at 1800 rpm
because of my amphib brakes. The other is that I may have got
some carb ice after sitting at idle so long waiting for my turn
to take off. OAT on the ground at that time was about 5 C (40F).
Or maybe my plugs fouled up a bit with lead with the long idle.
Any thoughts? I don't like mysteries of this kind.
Walter
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WALTER KLATT
Rebel Fuel Management
Yeah, I guess that might be possible in your case if your carb heat muffs weren't warm enough yet to provide enough heat to melt the carb ice. Can't imagine that with mine, though, as even idling at 1200 soon after start up, if I pull carb heat, my engine rpms drop indicating hot air into the carb.
On the other hand, you might have had some frozen moisture blocking fuel flow somewhere (even in your carb bowl) which melted and passed through after you got back on the ground. I have had carb ice at least a couple times now in cruise and each time it cleared up in a few seconds after applying carb heat. I would have expected that if the plane is making enough power to fly, it should have enough heat from the muffs to melt carb ice. Also, as I understand it, carb ice is less likely in real cold weather, ie well below freezing. When I had mine, it was actually in summer, when I least expected it, too, although conditions were obviously humid and I was at higher altitudes.
Walter
----- Original Message -----
From: bosdes@att.net (Ted Hauri)
Date: Tuesday, December 14, 2004 2:39 pm
Subject: Re: Rebel Fuel Management
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On the other hand, you might have had some frozen moisture blocking fuel flow somewhere (even in your carb bowl) which melted and passed through after you got back on the ground. I have had carb ice at least a couple times now in cruise and each time it cleared up in a few seconds after applying carb heat. I would have expected that if the plane is making enough power to fly, it should have enough heat from the muffs to melt carb ice. Also, as I understand it, carb ice is less likely in real cold weather, ie well below freezing. When I had mine, it was actually in summer, when I least expected it, too, although conditions were obviously humid and I was at higher altitudes.
Walter
----- Original Message -----
From: bosdes@att.net (Ted Hauri)
Date: Tuesday, December 14, 2004 2:39 pm
Subject: Re: Rebel Fuel Management
I took the Champ up one fine day in Winter a couple of years ago.
I landed at Hampton (grass field) and when I left about a half
hour later, I had to wait awhile before the runway was clear for
takeoff. There was a lot of ice in the taxi area, so while I
waited I ran around 1200 RPM, and because of the ice I didn't do a
runup. I barely cleared the trees (lucky for me the air was cold),
and as I limped around the pattern tried carb heat to no avail.
But it was carb ice. Ten minutes on the ground and the radiant
heat from the engine melted the ice. I taxied with carb heat to
takeoff, and had no problems that time.
-------------- Original message from Walter Klatt
<Walter.Klatt@shaw.ca>: --------------
thatWent flying this weekend and had some fuel management issuesandI still don't totally understand, so thought I would share with
the group, as it might affect you one day, too.
Usually in the winter, I transition from mogas to avgas, and was
last flying with one tank avgas and using up the last of the
mogas in the other. Anyway, I didn't get it quite empty on my
previous flight, so decided to drain the last of it (only 2 gal
left) through my gascolator, so I could fill up that tank, too,
with pure avgas.
While draining the mogas tank, I, of course, closed the other
avgas tank fuel valve. When finished, I closed the empty tank
valve and opened the other avgas tank again, and started the
engine to go fuel up my empty tank at the pumps. The engine
started fine, and I began my taxi. Well, I barely got going when
the engine quit. And I could not start it, no matter what. It
fired up a couple of times, but would not continue running. I
then opened up the closed empty tank, and after a short wait
(maybe 20 seconds) I then started and was able to continue on to
the fuel pump without further interruption.
This has actually happened to me before, while still on the
ground, with similar circumstances after draining a tank, but
wasn't exactly sure if it was a fluke or what. The fact that it
happened again, makes me very leery of ever running one tank dry
in the air. The tank that I switched to had exactly 15 US g, so
it wasn't anywhere near empty. What was interesting is that I
couldn't get the engine started until I opened the other empty
tank. So my theory is, it allowed the air to escape up there,isthen the fuel was able to flow freely from the full tank. My
tanks are plumbed so that the shut off valves are up top at the
tank outlets, and the lines are not tee'd together until just
before the gascolator on the firewall. I also have a fuel flow
sender that is on the output of the gascolator, that I believe
costs at most 0.5 PSI to operate. No fuel pumps, just gravity
feed.
Anyway, I think I have heard Bob P say, and maybe others that
they have run one tank dry in the air, and no problem. So my
question is, how exactly did you do that and exactly how low was
the fuel in the new tank? As I said, mine was 15 g, and it still
didn't start. When you opened the good tank, did you first close
the empty tank, or was it still open? I am just wondering whatopen,the better procedure. From my ground experience, it would seem
that it is better to leave the empty tank open until the engine
is running fine on the new tank.
I often fly with one tank, and switch tanks in flight, but have
never run one dry. When I do get low in one tank, as I did in my
previous flight (only 2 gal left) I switch to both before
landing, or when I am not over water. So I would like to
understand this better before I try running one tank completely
dry.
OK, that was one fuel issue. On the same day, when I took off,
after fuelling, I had another, that may or may not be related.
Here is what happened. I did my run-up, with both tanks nowdidn'tand proceeded to the runway, but had to hold about 5 minutes
while other planes landed, and another ahead of me waited his
turn also. It's not normally that busy here, but it was a rare
nice day, and of course everybody decided to go flying. Anyway,
right after take-off, I noticed my rpm fluctuate and drop to low
2400's and even into the 2300's for a couple of seconds. Iaboutnotice that it ran rough, just not full power. I climbed tosecond300 feet and then abandoned our noise abatement path and started
a left turn so I could catch the crosswind grass runway if I had
to. It continued to climb though, and then resumed its usual
climb rpm of 2550, and ran just fine after that. The rest of my
flying that day was uneventful, but needless to say, I wasn't
happy with what happened.
I have a couple of theories on this last issue. One is that I
still may have had some air in my lines after bringing thetank online after fuelling. My run-ups are only at 1800 rpm
because of my amphib brakes. The other is that I may have got
some carb ice after sitting at idle so long waiting for my turn
to take off. OAT on the ground at that time was about 5 C (40F).
Or maybe my plugs fouled up a bit with lead with the long idle.
Any thoughts? I don't like mysteries of this kind.
Walter
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Angus McKenzie
Rebel Fuel Management
Hi Walter
I too run my first tank dry.I always run my right tank first then at the
first engine sputter reach over my head and open the left valve then reach
across and shut off the other side. Usually get 2.5 hrs per side,depending
on how rough the air is.............Angus
----- Original Message -----
From: "WALTER KLATT" <Walter.Klatt@shaw.ca>
To: <rebel-builders@dcsol.com>
Sent: Tuesday, December 14, 2004 11:42 AM
Subject: Re: RE: Rebel Fuel Management
are the lines tee'd together?
you open the full one first, and close the empty one after the engine starts
up again?
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I too run my first tank dry.I always run my right tank first then at the
first engine sputter reach over my head and open the left valve then reach
across and shut off the other side. Usually get 2.5 hrs per side,depending
on how rough the air is.............Angus
----- Original Message -----
From: "WALTER KLATT" <Walter.Klatt@shaw.ca>
To: <rebel-builders@dcsol.com>
Sent: Tuesday, December 14, 2004 11:42 AM
Subject: Re: RE: Rebel Fuel Management
you have the standard MAM shut-off valves up top at the tank outlets? WhereDrew, can you give me a couple more specifics about your fuel system. Do
are the lines tee'd together?
valves? Do you first close the empty tank and then open the full one? Or doAnd when you run a tank dry, exactly what order do you open and close the
you open the full one first, and close the empty one after the engine starts
up again?
Walter
----- Original Message -----
From: Drew Dalgleish <drewjan@cabletv.on.ca>
Date: Tuesday, December 14, 2004 7:26 am
Subject: RE: Rebel Fuel Management
At 08:41 PM 12/13/2004 -0800, you wrote:Hi Walter I've run one tank dry in flight a few times on long crossBoth caps have forward facing tube vents, and the tanks are
connected with a vent tube through the cabin. I do not lean when
idling, which is why I thought, too, that it might have been lead
fouling. I drained the tank dry through my gascolator, so if
there was any crap, it would have shown up then. I also did a
final fuel sampling from all my drains and gascolator after
fuelling, and again no water or crap.
I'm sure my first issue was because of air trapped in the lines
as Wayne described. And that was cleared up by opening the empty
tank valve. But that just raised my question of how some people
(Bob P or others?) have done it in flight without any problems.
So far now, I will continue my current practice of not ever
running one tank dry in flight. And again just as Wayne
described, when low on fuel, I may shut one down to get them
balanced, but use both when really low, or flying over hostile
terrain.
I will also remember Wayne's suggestion of using the primer to
relieve air, if I ever encounter that situation again.
Walter
countries when I'm getting near maximun range for the fuel
carried. I feel
better having all my remaining fuel in one tank rather than split
between 2
just because I've also had the problem of unporting the intake
pipe with
low fuel when cranking and banking close to the ground. My vent is
at the
wing root on the pilots side and that tank seems to feed a little
fasterthan the other one. so it's easier to manage just one tank
at a time.
Drew
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