Extra fuel vent vs another pump


Peter Harris <peterjfharris@...>
 

Jim if your vent is located down into the return pipe it will fill with fuel when fuel surges up the return pipe. When the main is full then during turbulence it has nowhere else to go but up the return pipe, and into the vent.And with the filler setup you have then the return pipe will in fact be filled to begin.
Not good for supply to the carb.
Peter
< the 3/16"? vent tube located about 1/2"
down into the 5/8" return tube to the main. The advantage of filling
from the top (mine is different than stock, 5 gallon header tank is
on pax side only) into the header allows me to fill the main and
header at the same time, stopping when both are level with the 2 1/2"
fill tube to the main which is about 1 1/2" from top of fuselage(can
fill plane very quickly). This keeps the vent clear at all times.>

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Peter Harris <peterjfharris@...>
 

Jim fuel rushes back up the fuel return line (and into the vent) if the main is full and during turbulence or even rotation. There is nowhere else for that fuel to go but up the return line and into the vent.
I accept that there have been no problems noticed by the Q200 even although fuel flow to the carbs is being affected. But it is not the vent for me as I do not want to compromise supply to the carb.and it should definitely not be used without a fuel bowl as I know from experience.
Cheers ,
Peter

----- Original Message -----
From: Jim Patillo
To: Q-LIST@...
Sent: Friday, June 03, 2005 8:36 AM
Subject: [Q-LIST] Re: Extra fuel vent vs another pump


Peter,

As previously stated, my 5/8" return line is at the very top of the
header with the 3/16"? vent tube bent into the top of it. The fuel
in header is consistantly 1-1/2" below that level when full. The
only time that was not the case was when I mistakenly added fuel
from the aux tank into two already full tanks. That was complete
stupidity and lack of fuel management on my part. But I got
distracted and it happened to me. It can happen to others with
similar setups. Other than that *&%$UP, I have not experienced a
problem with it in 600 hours that I am aware of. Will make some
pictures available in a little while.

Regards,

Jim P. N46JP Q200 Heading for Golden West EAA Fly In tomorrow after
I pick up Sam Kittle in Calaveras County, CA.

--- In Q-LIST@..., "Peter Harris" <peterjfharris@b...>
wrote:
> Jim if your vent is located down into the return pipe it will fill
with fuel when fuel surges up the return pipe. When the main is full
then during turbulence it has nowhere else to go but up the return
pipe, and into the vent.And with the filler setup you have then the
return pipe will in fact be filled to begin.
> Not good for supply to the carb.
> Peter
> < the 3/16"? vent tube located about 1/2"
> down into the 5/8" return tube to the main. The advantage of
filling
> from the top (mine is different than stock, 5 gallon header tank
is
> on pax side only) into the header allows me to fill the main and
> header at the same time, stopping when both are level with the 2
1/2"
> fill tube to the main which is about 1 1/2" from top of fuselage
(can
> fill plane very quickly). This keeps the vent clear at all times.>
>
> Quickie Builders Association WEB site
> http://www.quickiebuilders.org
>
>
>
>
>
>
> -------------------------------------------------------------------
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> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
> http://groups.yahoo.com/group/Q-LIST/
>
> b.. To unsubscribe from this group, send an email to:
> Q-LIST-unsubscribe@...
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of Service.
>
>
>
>





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Jim Patillo
 

Fellas,

Actually after thinking about it further, the stock fuel vent setup I
have works perfectly with the 3/16"? vent tube located about 1/2"
down into the 5/8" return tube to the main. The advantage of filling
from the top (mine is different than stock, 5 gallon header tank is
on pax side only) into the header allows me to fill the main and
header at the same time, stopping when both are level with the 2 1/2"
fill tube to the main which is about 1 1/2" from top of fuselage(can
fill plane very quickly). This keeps the vent clear at all times.
After taxi out, fuel is even lower.

The problem that caused my engine failure was due to pumping from the
aux into an already full main and header. Like overfilling a bucket
it had to go somewhere and the path of least resistance was through
the vent.
The answer for me is DO NOT TURN ON THE AUX SWITCH PRIOR TO FLIGHT.
Just like, do not turn off the master/ignition prior to flight. It is
on my check list now!

I'll keep what I have. But if you are newly building or rebuilding
with a stock header take heed!

Regards,
Jim Patillo


Jerry Marstall <jnmarstall@...>
 

Another option for all of you to critically evaluate: use a separate vent for the aux tank. Putting a check valve in the fuel line would prevent loss of pressurization if a leak developed in the aux tank. Also, if the aux tank is turned on prematurely, as in Jim's situation, the main header tank vent could become full and overflow but the fuel system would remain pressurized from the vent for the aux tank.
Jerry

Jim Patillo wrote:

Fellas,

Actually after thinking about it further, the stock fuel vent setup I have works perfectly with the 3/16"? vent tube located about 1/2" down into the 5/8" return tube to the main. The advantage of filling from the top (mine is different than stock, 5 gallon header tank is on pax side only) into the header allows me to fill the main and header at the same time, stopping when both are level with the 2 1/2" fill tube to the main which is about 1 1/2" from top of fuselage(can fill plane very quickly). This keeps the vent clear at all times. After taxi out, fuel is even lower.

The problem that caused my engine failure was due to pumping from the aux into an already full main and header. Like overfilling a bucket it had to go somewhere and the path of least resistance was through the vent.
The answer for me is DO NOT TURN ON THE AUX SWITCH PRIOR TO FLIGHT. Just like, do not turn off the master/ignition prior to flight. It is on my check list now!

I'll keep what I have. But if you are newly building or rebuilding with a stock header take heed!

Regards,
Jim Patillo




Quickie Builders Association WEB site
http://www.quickiebuilders.org

Yahoo! Groups Links







Jim Patillo
 

Peter,

As previously stated, my 5/8" return line is at the very top of the
header with the 3/16"? vent tube bent into the top of it. The fuel
in header is consistantly 1-1/2" below that level when full. The
only time that was not the case was when I mistakenly added fuel
from the aux tank into two already full tanks. That was complete
stupidity and lack of fuel management on my part. But I got
distracted and it happened to me. It can happen to others with
similar setups. Other than that *&%$UP, I have not experienced a
problem with it in 600 hours that I am aware of. Will make some
pictures available in a little while.

Regards,

Jim P. N46JP Q200 Heading for Golden West EAA Fly In tomorrow after
I pick up Sam Kittle in Calaveras County, CA.

--- In Q-LIST@..., "Peter Harris" <peterjfharris@b...>
wrote:
Jim if your vent is located down into the return pipe it will fill
with fuel when fuel surges up the return pipe. When the main is full
then during turbulence it has nowhere else to go but up the return
pipe, and into the vent.And with the filler setup you have then the
return pipe will in fact be filled to begin.
Not good for supply to the carb.
Peter
< the 3/16"? vent tube located about 1/2"
down into the 5/8" return tube to the main. The advantage of
filling
from the top (mine is different than stock, 5 gallon header tank
is
on pax side only) into the header allows me to fill the main and
header at the same time, stopping when both are level with the 2
1/2"
fill tube to the main which is about 1 1/2" from top of fuselage
(can
fill plane very quickly). This keeps the vent clear at all times.>

Quickie Builders Association WEB site
http://www.quickiebuilders.org






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Bob Farnam <bfarnam@...>
 

How do we know that turbulence will drive fuel up the return pipe and fill
the vent? Has this been measured or observed or is it conjecture? It seems
to me that only prolonged negative "G" could possibly cause that. I
certainly isn't intended to be an inverted fuel system.
Bob F.
N200QK
EAA Flight Advisor

-----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...]On Behalf Of
Peter Harris
Sent: Wednesday, June 01, 2005 2:40 PM
To: Q-LIST@...
Subject: Re: [Q-LIST] Extra fuel vent vs another pump


Jim if your vent is located down into the return pipe it will fill with
fuel when fuel surges up the return pipe. When the main is full then during
turbulence it has nowhere else to go but up the return pipe, and into the
vent.And with the filler setup you have then the return pipe will in fact be
filled to begin.
Not good for supply to the carb.
Peter
< the 3/16"? vent tube located about 1/2"
down into the 5/8" return tube to the main. The advantage of filling
from the top (mine is different than stock, 5 gallon header tank is
on pax side only) into the header allows me to fill the main and
header at the same time, stopping when both are level with the 2 1/2"
fill tube to the main which is about 1 1/2" from top of fuselage(can
fill plane very quickly). This keeps the vent clear at all times.>

Quickie Builders Association WEB site
http://www.quickiebuilders.org






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Peter Harris <peterjfharris@...>
 

Bob it has been observed when the main is full, that fuel is forced up the return vent when you step on the seat which acts like a bellows. It can also be observed if you have a transparent return hose. Now that I have sealed the plans vent and operate only with an up-vent which is inserted into the return line I get the occasional bubble which could only come from the return pipe. My Revmaster/Posa stopped with the plans vent which was also inserted into the return line.
Peter

----- Original Message -----
From: Bob Farnam
To: Q-LIST@...
Sent: Tuesday, June 07, 2005 2:53 AM
Subject: RE: [Q-LIST] Extra fuel vent vs another pump


How do we know that turbulence will drive fuel up the return pipe and fill
the vent? Has this been measured or observed or is it conjecture? It seems
to me that only prolonged negative "G" could possibly cause that. I
certainly isn't intended to be an inverted fuel system.
Bob F.
N200QK
EAA Flight Advisor

-----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...]On Behalf Of
Peter Harris
Sent: Wednesday, June 01, 2005 2:40 PM
To: Q-LIST@...
Subject: Re: [Q-LIST] Extra fuel vent vs another pump


Jim if your vent is located down into the return pipe it will fill with
fuel when fuel surges up the return pipe. When the main is full then during
turbulence it has nowhere else to go but up the return pipe, and into the
vent.And with the filler setup you have then the return pipe will in fact be
filled to begin.
Not good for supply to the carb.
Peter
< the 3/16"? vent tube located about 1/2"
down into the 5/8" return tube to the main. The advantage of filling
from the top (mine is different than stock, 5 gallon header tank is
on pax side only) into the header allows me to fill the main and
header at the same time, stopping when both are level with the 2 1/2"
fill tube to the main which is about 1 1/2" from top of fuselage(can
fill plane very quickly). This keeps the vent clear at all times.>

Quickie Builders Association WEB site
http://www.quickiebuilders.org






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Service.







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