X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3.6) with ESMTP id 617884 for flyrotary@lancaironline.net; Thu, 28 Jul 2005 13:44:12 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-065-188-083-049.carolina.res.rr.com [65.188.83.49]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j6SHhOL5011206 for ; Thu, 28 Jul 2005 13:43:25 -0400 (EDT) Message-ID: <000701c5939b$dbaf4d40$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] fuel filter question Date: Thu, 28 Jul 2005 13:43:26 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C5937A.54588DF0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0004_01C5937A.54588DF0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Kevin, I suspect you are correct about the design flaw.=20 According to the data you provided - your fuel flow capacity with the = two 1/8" holes and the 1/4" common passage is way below what I have with = a standard 3/8" dia fuel line. Your two 1/8" parallel flow holes only provide a total of 0.024544 = square inches of flow area. The 1/4" common passage (tube??) only = provides 0.049087 square inches. Whereas the standard 3/8" dia fuel = line provides 0.110447 sq inch of flow are. So if i understand your system, it appears to me it may limit flow to = only from 22 - 44 % of what the standard 3/8" line gives you. Could be = I simply did not understand your descriptions correctly - but that's the = way it appears to me. If correct then that could explain why your system will not support full = throttle. Also may account for the lower than expected pressure for a = facet pump - mine puts out 6 psi. =20 So from your previous description of your troubles, I think you are able = to maintain 2200 rpm simply until your float bowl is sucked down to a = steady state condition (that supportable by the rate of fuel flow = through your simple - which appears to be restricted) then your engine = rpm drops until it reaches the rpm that the sustainable fuel flow = supports and NO MORE. My 0.02 worth Ed A ----- Original Message -----=20 From: kevin lane=20 To: Rotary motors in aircraft=20 Sent: Thursday, July 28, 2005 12:43 PM Subject: [FlyRotary] fuel filter question I suspect that my engine problems stem from a design flaw, rather than = a blockage. I normally never run my engine full power, full rich, but = have been while breaking in the new rings. even leaning the engine a = few notches prevents my problem, so it never arose in the past. my auto = fuel filters are on the "suck" side, between the tanks and the selector = valve. they are small, glass see-thru mesh filters. I realize now that = all the fuel passes thru a pair of like 1/8" holes from a common 1/4" = passage. I also see that the facet pump, despite pumping 15+ gals / hr = with no head pressure, will only produce 1.75 lbs pressure when attached = to the carb and bypassing the manual pump. my question - I was told not to use a fuel injection filter on a = low pressure system like mine. I would like to keep the filters where = they are rather than moving them to the engine compartment, since they = filter stuff ahead of my flow meter and pumps. I like how they fit = along the wing spar below my knees. I had problems with the replaceable = filters shedding fibers into the carb, which is why I changed to the = mesh filters. does anyone know what I should be using? I plan to do more testing this weekend if my wife will let me = drive her car("no, I'm not feeling sleepy :-)" to get to the airport. Kevin Lane Portland, OR e-mail-> n3773@comcast.net ------=_NextPart_000_0004_01C5937A.54588DF0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Kevin,
 
I suspect you are correct about the design=20 flaw. 
 
According to the data you provided - your fuel = flow=20 capacity with the two 1/8" holes and the 1/4" common passage is way = below what I=20 have with a standard 3/8" dia fuel line.
 
Your two 1/8" parallel flow holes only provide a = total=20 of   0.024544 square inches=20 of flow area.  The 1/4" common passage (tube??) only = provides  0.049087 square = inches. =20 Whereas the standard 3/8" dia fuel line provides  0.110447 sq inch of flow=20 are.
 
So if i understand your system, it appears to me = it may=20 limit flow to only from 22 - 44 % of what the standard 3/8" line gives=20 you.   Could be I simply did not understand your descriptions=20 correctly - but that's the way it appears to me.
 
If correct then that could explain why your = system will=20 not support full throttle.  Also may account for the lower than = expected=20 pressure for a facet pump - mine puts out 6 psi. 
 
So from your previous description of your = troubles, I=20 think you are able to maintain 2200 rpm simply until your float bowl is = sucked=20 down to a steady state condition (that supportable by the rate of fuel = flow=20 through your simple - which appears to be restricted) then your engine = rpm drops=20 until it reaches the rpm that the sustainable fuel flow supports and NO=20 MORE.
 
My 0.02 worth
 
Ed A
----- Original Message -----
From:=20 kevin = lane=20
Sent: Thursday, July 28, 2005 = 12:43=20 PM
Subject: [FlyRotary] fuel = filter=20 question

I suspect that my engine = problems stem=20 from a design flaw, rather than a blockage.  I normally never run = my=20 engine full power, full rich, but have been while breaking in the new=20 rings.  even leaning the engine a few notches prevents my = problem, so it=20 never arose in the past.  my auto fuel filters are on the "suck" = side,=20 between the tanks and the selector valve.  they are small, glass = see-thru=20 mesh filters.  I realize now that all the fuel passes thru a pair = of like=20 1/8" holes from a common 1/4" passage.  I also see that the facet = pump,=20 despite pumping 15+ gals / hr with no head pressure, will only produce = 1.75=20 lbs pressure when attached to the carb and bypassing the manual=20 pump.
    my = question - I was=20 told not to use a fuel injection filter on a low pressure system like=20 mine.  I would like to keep the filters where they are rather = than moving=20 them to the engine compartment, since they filter stuff ahead of my = flow meter=20 and pumps.  I like how they fit along the wing spar below my = knees. =20 I had problems with the replaceable filters shedding fibers into the = carb,=20 which is why I changed to the mesh filters.   does anyone = know what=20 I should be using?
    I plan = to do more=20 testing this weekend if my wife will let me drive her car("no, I'm not = feeling=20 sleepy :-)" to get to the airport.
Kevin Lane  Portland, OR
e-mail-> n3773@comcast.net
 
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