REFLECTOR:Fuel filters
John Dibble
reflector@tvbf.org
Tue, 17 Feb 2004 12:45:16 -0600
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That's a nice setup. When I bought my Velocity it had 205 hours and no
filter, so I doubt that a little unfiltered fuel is going to be a big
problem. I did have an occasional slow fuel leak at the carbureator (I
could "fix" it by shutting off the fuel and running the engine until the
bowl was empty - on the ground of course.) My guess is that the float
valve was dirty and not sealing well. I just replaced the float valve
and seat so soon I will know it that was the problem. The bowl and
valve were very clean with no sediment.
John
Brian Michalk wrote:
> I'm sure something like that exists, but would you want unfiltered
> fuel plugging up your system?
> There are commercial filters that have a sensor that tells you when
> the filter is plugged, but you could roll one yourself by putting a
> pressure sensor on each side of the filter. As the filter becomes
> clogged, the pressure across the filter increases, showing up as a
> delta voltage on your sensors.
>
> I've gone perhaps a little overboard instrumenting my airplane ... I
> do instrumentation for a living. I've got sensors at each fuel pump
> output ... I'll draw a picture. It's easier.
>
>
> EFP-->PS1-->CV-->FILT
> \
> TEE-->PS3-->flow1-->FPR-->flow2-->PS4-->engine
> /
> MFP-->PS2-->CV-->FILT
>
> EFP-electric driven fuel pump
> MFP-mechanical driven fuel pump
> PS1-pressure from electric fuel pump
> PS2-pressure from mechanical fuel pump
> FILT-fuel filters
> CV-check valve
> PS3-pressure at input of fuel pressure regulator
> flow1-total fuel flow from pumps
> FPR-fuel pressure regulator, dumps excess back to sump
> flow2-fuel flow going to engine
> PS4-fuel pressure at engine injectors
>
> So a delta pressure between PS1:PS3 and PS2:PS3 will indicate a
> blocked fuel filter.
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of John Dibble
> Sent: Tuesday, February 17, 2004 9:58 AM
> To: reflector@tvbf.org
> Subject: Re: REFLECTOR:Fuel filters
>
> I have a cheap in-line filter and also worry about fuel
> restriction. I checked it after 10 hours and it seemed to flow as
> well as a new filter. So I feel comfortable it will last 100
> hours anyway. I guess the one good thing about fuel restriction
> is that it should happen at the beginning of the takeoff roll
> where there is room to abort. Do they make filters that allow the
> flow to bypass if the filter becomes plugged? Or a separate
> "pressure relief" valve that can be installed in parallel with the
> filter?
>
> John
>
> Gilles Gratton wrote:
>
>> Is anyone out there using the K & N Billet Aluminum Fuel filter?
>> If so, do you recommend it? I plan to use it on my Franklin
>> engine to replace that small miniature glass filter which I have
>> been using so far , successfully but with constant fear and
>> apprehension that it will restrict fuel flow and starve my engine
>> in a moment of high fuel demand.
>> Gilles Gratton
>
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That's a nice setup. When I bought my Velocity it had 205 hours and no
filter, so I doubt that a little unfiltered fuel is going to be a big
problem. I did have an occasional slow fuel leak at the carbureator (I
could "fix" it by shutting off the fuel and running the engine until
the bowl was empty - on the ground of course.) My guess is that the
float valve was dirty and not sealing well. I just replaced the float
valve and seat so soon I will know it that was the problem. The bowl
and valve were very clean with no sediment.<br>
<br>
John<br>
<br>
Brian Michalk wrote:<br>
<blockquote type="cite"
cite="midNGBBLKIBLMDNILPAICAJIEDJFIAA.michalk@awpi.com">
<title></title>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<meta content="MSHTML 5.00.2614.3500" name="GENERATOR">
<div><font color="#0000ff" face="Fixedsys" size="2"><span
class="440115815-17022004">I'm sure something like that exists, but
would you want unfiltered fuel plugging up your system?</span></font></div>
<div><font color="#0000ff" face="Fixedsys" size="2"><span
class="440115815-17022004">There are commercial filters that have a
sensor that tells you when the filter is plugged, but you could roll
one yourself by putting a pressure sensor on each side of the filter.
As the filter becomes clogged, the pressure across the filter
increases, showing up as a delta voltage on your sensors.</span></font></div>
<div> </div>
<div><font color="#0000ff" face="Fixedsys" size="2"><span
class="440115815-17022004">I've gone perhaps a little overboard
instrumenting my airplane ... I do instrumentation for a living. I've
got sensors at each fuel pump output ... I'll draw a picture. It's
easier.</span></font></div>
<div> </div>
<div> </div>
<div><strong><font color="#0000ff" face="Fixedsys" size="2"><span
class="440115815-17022004">EFP-->PS1-->CV-->FILT</span></font></strong></div>
<div><strong><font color="#0000ff" face="Fixedsys" size="2"><span
class="440115815-17022004"> \</span></font></strong></div>
<div><strong><font color="#0000ff" face="Fixedsys" size="2"><span
class="440115815-17022004">
TEE-->PS3-->flow1-->FPR-->flow2-->PS4-->engine</span></font></strong></div>
<div><strong><font color="#0000ff" face="Fixedsys" size="2"><span
class="440115815-17022004"> /</span></font></strong></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong>MFP-->PS<span
class="440115815-17022004">2</span>-->CV<span
class="440115815-17022004">-->FILT</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong></strong></font></font></font> </div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">EFP-electric driven fuel pump</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">MFP-mechanical driven fuel pump</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">PS1-pressure from electric fuel pump</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">PS2-pressure from mechanical fuel pump</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">FILT-fuel filters</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">CV-check valve</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">PS3-pressure at input of fuel pressure
regulator</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">flow1-total fuel flow from pumps</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">FPR-fuel pressure regulator, dumps excess
back to sump</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">flow2-fuel flow going to engine</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">PS4-fuel pressure at engine injectors</span></strong></font></font></font></div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong></strong></font></font></font> </div>
<div><font size="2"><font color="#0000ff"><font face="Fixedsys"><strong><span
class="440115815-17022004">So a delta pressure between PS1:PS3 and
PS2:PS3 will indicate a blocked fuel filter.</span></strong></font></font></font></div>
<blockquote
style="border-left: 2px solid rgb(0, 0, 255); margin-left: 5px; margin-right: 0px; padding-left: 5px;">
<div align="left" class="OutlookMessageHeader" dir="ltr"><font
face="Tahoma" size="2">-----Original Message-----<br>
<b>From:</b> <a class="moz-txt-link-abbreviated" href="mailto:reflector-admin@tvbf.org">reflector-admin@tvbf.org</a>
[<a class="moz-txt-link-freetext" href="mailto:reflector-admin@tvbf.org">mailto:reflector-admin@tvbf.org</a>]<b>On Behalf Of </b>John Dibble<br>
<b>Sent:</b> Tuesday, February 17, 2004 9:58 AM<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:reflector@tvbf.org">reflector@tvbf.org</a><br>
<b>Subject:</b> Re: REFLECTOR:Fuel filters<br>
<br>
</font></div>
I have a cheap in-line filter and also worry about fuel restriction. I
checked it after 10 hours and it seemed to flow as well as a new
filter. So I feel comfortable it will last 100 hours anyway. I guess
the one good thing about fuel restriction is that it should happen at
the beginning of the takeoff roll where there is room to abort. Do
they make filters that allow the flow to bypass if the filter becomes
plugged? Or a separate "pressure relief" valve that can be installed
in parallel with the filter?<br>
<br>
John<br>
<br>
Gilles Gratton wrote:<br>
<blockquote cite="midDAEDKOMCBHINGJEIJCOJIEHGCJAA.gratton@magma.ca"
type="cite">
<meta content="MSHTML 6.00.2800.1400" name="GENERATOR">
<div><font face="Arial" size="2"><span class="810285815-15022004">Is
anyone out there using the K & N Billet Aluminum Fuel filter? If
so, do you recommend it? I plan to use it on my Franklin engine to
replace that small miniature glass filter which I have been using so
far , successfully but with constant fear and apprehension that it will
restrict fuel flow and starve my engine in a moment of high fuel
demand. </span></font></div>
<div><font face="Arial" size="2"><span class="810285815-15022004">Gilles
Gratton</span></font></div>
</blockquote>
</blockquote>
</blockquote>
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