X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from outbound-mail02.dca.untd.com ([64.136.47.36] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with SMTP id 6295764 for flyrotary@lancaironline.net; Wed, 29 May 2013 10:01:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.136.47.36; envelope-from=alwick@juno.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=juno.com; s=alpha; t=1369836030; bh=47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=; l=0; h=Message-ID:From:To:Subject:Date:Content-Type; b=Qp0wT5PGOL4JYNykw7uwzFzjPf4IOT9a6u+XaBkFT2MtyfE68bQDPZVb3WpzHWDB8 51pwpSsL61H5yS8A4sEdUVDPQ3//825PIe/F+zsQucmUPTkB/dM3lwvXm9K75sG+cm dDRRe/BPaIUz2ork2DXxsLD1ed87gXTDg6DOb5ew= Received: from Penny (50-39-187-139.bvtn.or.frontiernet.net [50.39.187.139]) by smtpout03.dca.untd.com with SMTP id AABJ4NCQXA3DUAWJ for (sender ); Wed, 29 May 2013 06:59:49 -0700 (PDT) Message-ID: From: "Al Wick" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Intermittent fuel pressure loss Date: Wed, 29 May 2013 06:59:48 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_04BA_01CE5C3A.1B97B9F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18197 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18463 X-UNTD-BodySize: 9099 X-ContentStamp: 22:11:1756470090 X-MAIL-INFO:0d13beabbef7df5ef7abde97abda63db67cf37ef9a3eba9fefcf074b075e5bba7e07dbc717ae17aeee5fae6eee8e6eee7a7edeafda9a7a63abcbdadfca4f6a6a93c36bb702175bae0e1e176e5757a71e0f7bd7eb1b5f1b2fbfcb63a36eee2f57d77a4e8f0e2e8a7f678f0e2e4b83834edbe34ecfbe7aee8f2e87af077713e31397ce7e5a2a37cfbe1aababd35edfaf27deaacb X-UNTD-OriginStamp: L941HVjjYzDhN3itp//mkON7w/dNu3BkfcR9vZuZawUADV6S0oVUhA== X-UNTD-Peer-Info: 10.171.42.33|smtpout03.dca.untd.com|smtpout03.dca.untd.com|alwick@juno.com This is a multi-part message in MIME format. ------=_NextPart_000_04BA_01CE5C3A.1B97B9F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hey Bill. A whole bunch of tests you can do without flying. I'd sure = encourage that. Highly unlikely it's a fuel pump unless you routinely = operate them without fuel. As Jeff suggests, fuel is important pump = lubricant, should resist urge to run sys dry.=20 If you shared pics, it would help. Particularly gascolator, pump, = plumbing.=20 Since you get consistent good results from turning on second pump, that = points to flow restriction as likely cause. So a good test would be to = undo fitting at engine and pump fuel into bucket. Measure volume with = ruler and stopwatch. Pump 1, pump 2. This will also disprove pump = theory. You could repeat test by disconnecting fuel return line. This is = more severe test as now pump has to achieve 40 psi. Bad pump would not = flow much volume at 40 psi.=20 Methodically go thru sys looking for debris, kink. Not just gascolator, = but other areas too. It's possible to have gascolator leak air and lean = sys.=20 For that matter, you may have engine running lean due to intake leak = (other?), 2nd pump adds touch more fuel per injector pulse. Thus masking = true cause. So I'd do the propane test (or other) for intake leak. = Something loosen during flight and allow leak. Poke and push on = components. Review o2 sensor values. By chance do you record these = things during flight? Do you have other data that can prove it was or = was not lean? Verify each pump has independent grounds, power supply. Verify sys = voltage. Recalibrate fuel pressure sender.=20 We have natural tendency to say "aha, I bet that's it". Forgetting that = there are some simple tests to prove it. This is important time to be = conservative and methodical.=20 Good luck.=20 -al wick ----- Original Message -----=20 From: Bill Bradburry=20 To: Rotary motors in aircraft=20 Sent: Monday, May 27, 2013 7:09 AM Subject: [FlyRotary] Intermittent fuel pressure loss Has anyone had an instance of intermittent failure of the fuel pumps? = A couple of days ago the engine started to intermittently lose power and changed tanks. (both tanks were low, about 5 gal in right and 10 or so = in left) The problem stopped so I thought I had unported the right tank. Several minutes later it started again on the left tank and I turned = on the other fuel pump. That seemed to stop it again. I still suspected = that I had unported the tanks. A couple of days later, I took off with about 45 gal and after about a = 30 min flight, the engine lost power again twice. I turned the other = fuel pump on and the problem stopped. My fuel system goes thru a Gascolator then to the two pumps, then to a = fuel filter. I assume that the Gascolator or the fuel filter could be = getting clogged, but I don't think that the other pump would bring the = pressure back if that were the case. I only have about 70 flight hours on the pump = and maybe about 100 hours total including ground runs. Also on the flight back, I had both pumps on and showing 40 lbs of = pressure. I then turned the secondary pump off and the pressure held at 40 lbs. = This strikes me that it is an intermittent pump failure. I plan to clean = the Gascolator, replace the fuel filter, and replace the pump. Any thoughts, suggestions, experiences? =20 My wife was with me on the last incident and I don't think she is = interested in trying to join Ed's glider club! Bill B -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_04BA_01CE5C3A.1B97B9F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hey Bill. A whole bunch of tests you can do without flying. I'd = sure=20 encourage that. Highly unlikely it's a fuel pump unless you routinely = operate=20 them without fuel. As Jeff suggests, fuel is important pump lubricant, = should=20 resist urge to run sys dry.
 
If you shared pics, it would help. Particularly gascolator, pump, = plumbing.=20
 
Since you get consistent good results from turning on second pump, = that=20 points to flow restriction as likely cause. So a good test would be = to undo=20 fitting at engine and pump fuel into bucket. Measure volume with ruler = and=20 stopwatch. Pump 1, pump 2. This will also disprove pump theory. You = could repeat=20 test by disconnecting fuel return line. This is more severe test as now = pump has=20 to achieve 40 psi. Bad pump would not flow much volume at 40 psi.
 
Methodically go thru sys looking for debris, kink. Not just = gascolator, but=20 other areas too. It's possible to have gascolator leak air and lean sys. =
 
For that matter, you may have engine running lean due to intake = leak=20 (other?), 2nd pump adds touch more fuel per injector pulse. Thus masking = true=20 cause. So I'd do the propane test (or other) for intake leak. Something = loosen=20 during flight and allow leak. Poke and push on components. Review o2 = sensor=20 values. By chance do you record these things during flight? Do you have = other=20 data that can prove it was or was not lean?
 
Verify each pump has independent grounds, power supply. Verify sys = voltage.=20 Recalibrate fuel pressure sender.
 
We have natural tendency to say "aha, I bet that's it". Forgetting = that=20 there are some simple tests to prove it. This is important time to be=20 conservative and methodical.
 
Good luck.
 
-al wick
 
 
 
----- Original Message -----
From:=20 Bill=20 Bradburry
Sent: Monday, May 27, 2013 7:09 = AM
Subject: [FlyRotary] = Intermittent fuel=20 pressure loss

Has anyone had an instance of intermittent failure of = the fuel=20 pumps?  A
couple of days ago the engine started to = intermittently lose=20 power and
changed tanks. (both tanks were low, about 5 gal in right = and 10=20 or so in
left)  The problem stopped so I thought I had = unported the=20 right tank.
Several minutes later it started again on the left tank = and I=20 turned on the
other fuel pump.  That seemed to stop it = again.  I=20 still suspected that I
had unported the tanks.

A couple of = days=20 later, I took off with about 45 gal and after about a 30
min = flight, the=20 engine lost power again twice.  I turned the other fuel = pump
on and=20 the problem stopped.

My fuel system goes thru a Gascolator then = to the=20 two pumps, then to a fuel
filter.  I assume that the = Gascolator or the=20 fuel filter could be getting
clogged, but I don't think that the = other pump=20 would bring the pressure back
if that were the case.  I only = have=20 about 70 flight hours on the pump and
maybe about 100 hours total = including=20 ground runs.

Also on the flight back, I had both pumps on and = showing=20 40 lbs of pressure.
I then turned the secondary pump off and the = pressure=20 held at 40 lbs.  This
strikes me that it is an intermittent = pump=20 failure.  I plan to clean the
Gascolator, replace the fuel = filter, and=20 replace the pump.

Any thoughts, suggestions, experiences?  =

My wife was with me on the last incident and I don't think she = is=20 interested
in trying to join Ed's glider club!

Bill=20 B


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