REFLECTOR:Low fuel light
KeithHallsten
reflector@tvbf.org
Wed, 23 Jul 2003 20:20:45 -0700
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Re: REFLECTOR:Low fuel lightYes! Everything you say "SHOULD" be true. =
Unfortunately, we continue to get these reports from the flying =
population regarding odd behavior of the fuel/vent system! =20
I think that at times the vent system supplies air to the sump tank just =
a TINY bit more easily than the longer path through the strakes supplies =
fuel to the sump tank. It's probably a transient event, just persisting =
long enough to actuate the "low fuel" warning and scare the bejesus out =
of the pilot. I see little risk in shutting the vent line to the sump =
tank, thereby assuring that the flow into the sump tank must come from =
the strake tanks.
=20
----- Original Message -----=20
From: Ronnie Brown=20
To: reflector@tvbf.org=20
Sent: Wednesday, July 23, 2003 6:55 PM
Subject: Re: REFLECTOR:Low fuel light
If the vent lines slope upward to the manifold from the three tanks, =
there shouldn't be any problems trapping air or fuel. The fuel should =
go down and the vent air goes up. And the fuel in the sump tank vent =
should seek the same level as in the fuel in the main tanks, thereby =
keeping the sump tank full and the alarm off.
Ronnie
----- Original Message -----=20
From: KeithHallsten=20
To: reflector@tvbf.org=20
Sent: Wednesday, July 23, 2003 8:51 PM
Subject: Re: REFLECTOR:Low fuel light
Rene',
I'm not flying yet, so my comments can be discounted accordingly. I =
plan to install a manual vent shut-off valve between the sump tank and =
the vent manifold. The result will be that the vent system can allow =
the main strake tanks to drain, but can't introduce air into the sump =
tank. I have a theory that the vent line to the sump tank causes more =
problems than it solves, once the initial "burp" of air is allowed to =
escape from the sump tank (before engine start).
Keith Hallsten
=20
----- Original Message -----=20
From: Rene Dugas=20
To: reflector@tvbf.org=20
Sent: Wednesday, July 23, 2003 4:00 PM
Subject: RE: REFLECTOR:Low fuel light
Thanks Jack,
I felt that maybe the boundary layer was causing a vacuum allowing =
air to enter the sump but not the tanks. I don not want to over =
pressure my tanks and rupture them at high pressures. I can splice a =
gage into the line but wanted to glean info from the informed (flying) =
few. Since all three tanks are connected to the manifold I remain =
perplexed. Thanks for the info on the Vision. Two engine builders told =
me significant fluctuations with the engine pump are common but no =
pressure numbers were available. I talked to Lycoming. He air might be =
in the line but I don't see how. Thanks=20
Rene'
-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org] =
On Behalf Of Jack Sheehan
Sent: Wednesday, July 23, 2003 4:35 PM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:Low fuel light
Rene'
I can not say much about the low fuel light except that I have not =
had that on my XL-RG and I am not extending the vent. Mine is as you =
described in the plumbing except the vent line under the belly is cut =
off almost flush with the fuselage. I have tested my sump warning light =
durin the test flight period by getting pretty low on fuel and then =
pushing the nose over and maintain a dive for enough time for the sump =
light to start to flicker The low pressure warning from the VM1000 is a =
common indication. I have spoken with Vision micro about it and the good =
news is the VM1000 is working fine and the bad news is the lack of =
pressure is real. it is the way the lycoming pump works and if you have =
an analog system with low sensitivity you never see it. They have sent =
me a snubber to install in the sensor line which will in theory reduce =
thesensitivity. ther is a similar snubber device in the manifold =
pressure system. I will let you know when I get some free time to =
install it.
Jack
N55XL
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<BODY lang=3DEN-US vLink=3Dpurple link=3Dblue bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Yes! Everything you say "SHOULD" =
be=20
true. Unfortunately, we continue to get these reports from the =
flying=20
population regarding odd behavior of the fuel/vent system! =
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I think that at times the vent system =
supplies air=20
to the sump tank just a TINY bit more easily than the longer path =
through the=20
strakes supplies fuel to the sump tank. It's probably a transient =
event,=20
just persisting long enough to actuate the "low fuel" warning and scare =
the=20
bejesus out of the pilot. I see little risk in shutting the vent =
line to=20
the sump tank, thereby assuring that the flow into the sump tank must =
come from=20
the strake tanks.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2> </FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dromott@adelphia.net =
href=3D"mailto:romott@adelphia.net">Ronnie=20
Brown</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Wednesday, July 23, 2003 =
6:55=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: REFLECTOR:Low fuel =
light</DIV>
<DIV><BR></DIV>
<DIV><FONT size=3D2>If the vent lines slope upward to the manifold =
from the=20
three tanks, there shouldn't be any problems trapping air or =
fuel. The=20
fuel should go down and the vent air goes up. And the fuel in =
the sump=20
tank vent should seek the same level as in the fuel in the main tanks, =
thereby=20
keeping the sump tank full and the alarm off.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Ronnie</FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3DKeithHallsten@quiknet.com=20
href=3D"mailto:KeithHallsten@quiknet.com">KeithHallsten</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Wednesday, July 23, =
2003 8:51=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: REFLECTOR:Low =
fuel=20
light</DIV>
<DIV><BR></DIV>
<DIV><FONT face=3DArial size=3D2>Rene',</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I'm not flying yet, so my comments =
can be=20
discounted accordingly. I plan to install a manual vent =
shut-off valve=20
between the sump tank and the vent manifold. The result will =
be that=20
the vent system can allow the main strake tanks to drain, but can't=20
introduce air into the sump tank. I have a theory that the =
vent line=20
to the sump tank causes more problems than it solves, once the =
initial=20
"burp" of air is allowed to escape from the sump tank (before engine =
start).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Keith Hallsten</FONT></DIV>
<DIV><FONT face=3DArial size=3D2> </FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- =
</DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Drdugas@bayou.com href=3D"mailto:rdugas@bayou.com">Rene =
Dugas</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Wednesday, July 23, =
2003 4:00=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> RE: REFLECTOR:Low =
fuel=20
light</DIV>
<DIV><FONT face=3DArial size=3D2></FONT><BR></DIV>
<DIV class=3DSection1>
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy =
size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Thanks=20
Jack,</SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy =
size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I felt =
that maybe=20
the boundary layer was causing a vacuum allowing air to enter the =
sump but=20
not the tanks. I don not want to over pressure my tanks and =
rupture=20
them at high pressures. I can splice a gage into the line =
but wanted=20
to glean info from the informed (flying) few. Since all =
three tanks=20
are connected to the manifold I remain perplexed. Thanks for =
the=20
info on the Vision. Two engine builders told me significant=20
fluctuations with the engine pump are common but no pressure =
numbers were=20
available. I talked to Lycoming. He air might be in =
the line=20
but I don=92t see how. Thanks </SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy =
size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial">Rene=92</SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy =
size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"></SPAN></FONT> </P>
<P class=3DMsoNormal style=3D"MARGIN-LEFT: 0.5in"><FONT =
face=3DTahoma=20
size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">-----Original=20
Message-----<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">From:</SPAN></B>=20
reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org] =
<B><SPAN=20
style=3D"FONT-WEIGHT: bold">On Behalf Of </SPAN></B>Jack =
Sheehan<BR><B><SPAN=20
style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Wednesday, July 23, =
2003 4:35=20
PM<BR><B><SPAN style=3D"FONT-WEIGHT: bold">To:</SPAN></B>=20
reflector@tvbf.org<BR><B><SPAN=20
style=3D"FONT-WEIGHT: bold">Subject:</SPAN></B> Re: REFLECTOR:Low =
fuel=20
light</SPAN></FONT></P>
<P class=3DMsoNormal style=3D"MARGIN-LEFT: 0.5in"><FONT =
face=3DArial=20
size=3D2><SPAN style=3D"FONT-SIZE: 12pt"></SPAN></FONT> </P>
<DIV>
<P class=3DMsoNormal style=3D"MARGIN-LEFT: 0.5in"><FONT =
face=3D"Trebuchet MS"=20
color=3D#663333 size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt; COLOR: #663333; FONT-FAMILY: 'Trebuchet =
MS'">Rene'</SPAN></FONT></P></DIV>
<DIV>
<P class=3DMsoNormal style=3D"MARGIN-LEFT: 0.5in"><FONT =
face=3D"Trebuchet MS"=20
color=3D#663333 size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt; COLOR: #663333; FONT-FAMILY: 'Trebuchet =
MS'">I can=20
not say much about the low fuel light except that I have not had =
that on=20
my XL-RG and I am not extending the vent. Mine is as you described =
in the=20
plumbing except the vent line under the belly is cut off almost =
flush with=20
the fuselage. I have tested my sump warning light durin the test =
flight=20
period by getting pretty low on fuel and then pushing the nose =
over and=20
maintain a dive for enough time for the sump light to start to =
flicker The=20
low pressure warning from the VM1000 is a common indication. I =
have spoken=20
with Vision micro about it and the good news is the VM1000 is =
working fine=20
and the bad news is the lack of pressure is real. it is the way =
the=20
lycoming pump works and if you have an analog system with low =
sensitivity=20
you never see it. They have sent me a snubber to install in the =
sensor=20
line which will in theory reduce thesensitivity. ther is a similar =
snubber=20
device in the manifold pressure system. I will let you know when I =
get=20
some free time to install it.</SPAN></FONT></P></DIV>
<DIV>
<P class=3DMsoNormal style=3D"MARGIN-LEFT: 0.5in"><FONT =
face=3D"Trebuchet MS"=20
color=3D#663333 size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt; COLOR: #663333; FONT-FAMILY: 'Trebuchet =
MS'">Jack</SPAN></FONT></P></DIV>
<DIV>
<P class=3DMsoNormal style=3D"MARGIN-LEFT: 0.5in"><FONT =
face=3D"Trebuchet MS"=20
color=3D#663333 size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt; COLOR: #663333; FONT-FAMILY: 'Trebuchet =
MS'">N55XL</SPAN></FONT></P></DIV></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCK=
QUOTE></BODY></HTML>
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