X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 19 Jun 2011 19:56:11 -0400 Message-ID: X-Original-Return-Path: Received: from nm19.bullet.mail.bf1.yahoo.com ([98.139.212.178] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with SMTP id 5025398 for lml@lancaironline.net; Sun, 19 Jun 2011 17:40:44 -0400 Received-SPF: none receiver=logan.com; client-ip=98.139.212.178; envelope-from=mcmess1919@yahoo.com Received: from [98.139.212.153] by nm19.bullet.mail.bf1.yahoo.com with NNFMP; 19 Jun 2011 21:40:10 -0000 Received: from [98.139.211.194] by tm10.bullet.mail.bf1.yahoo.com with NNFMP; 19 Jun 2011 21:40:10 -0000 Received: from [127.0.0.1] by smtp203.mail.bf1.yahoo.com with NNFMP; 19 Jun 2011 21:40:10 -0000 X-Yahoo-Newman-Id: 348964.42614.bm@smtp203.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 2hVk8R8VM1nhQMqVVeDEdY3_PpyFrC_MgGGWYYXXqigVrpM wH00_cQOtrLyyWmB0mpIV7xjIj3U4OHSRxOEeVfv03YuJ.9WZIymoBiISPuA omXdEwxX3ttbfe20ZNc7rB_mzrO1EcBJbZhvdPTV3Jtt7Ig.VrS_2KWgwjid _aeoiEQsQF_nlLpNan81DwXy.38vTSZNJOsxtmfIC.ILPrBCZfmkyQAW9dRA LhgEUrYEpNqP0zHnMTeLSmEOrDW9I1JSlCTGk16WG5.cGxWpEYgBIgoMtzow 4C7VZrzb2LKfIR7JrKhnZf8fsNfvUCszZGVrXHX7m0XdfUjuexstQAm5vvXs oWd15mbQTCrFg7h6EO25FAN9dTNqvqT3RhQU- X-Yahoo-SMTP: rK4i7HqswBC7mDE8.sOiWQeO4CeReXc- Received: from StevePC (mcmess1919@67.187.173.57 with login) by smtp203.mail.bf1.yahoo.com with SMTP; 19 Jun 2011 14:40:09 -0700 PDT From: "Steve Colwell" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: fuel pressure and fuel flow X-Original-Date: Sun, 19 Jun 2011 14:40:13 -0700 X-Original-Message-ID: <00a101cc2ec9$795d65d0$6c183170$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00A2_01CC2E8E.CCFE8DD0" X-Mailer: Microsoft Office Outlook 12.0 Content-Language: en-us Thread-Index: AcwulauMRPHlZ5HxQW6FGNlUkImObAAMEGBg This is a multi-part message in MIME format. ------=_NextPart_000_00A2_01CC2E8E.CCFE8DD0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Berni, =20 My experience with an Aircoupe was enlightening. I found the source of = the problem to be a loop (imagine an inverted U) that trapped air, not = fuel vapor, in a section of fuel line. When the fuel valve was closed = and the lines between the valve and carburetor were drained, an air = bubble would trap in the high section of the loop when the valve was = reopened. On takeoff the high fuel flow would push some of the air to = the Gascolator where it trapped at the screen. Engines were quitting on = takeoff and many times the bubble would get enough agitation on the hard = landing to work though leaving no evidence in the glass bowl. It was a = faulty design later addressed by Service Letter. A temporary fix was to = force a high flow of fuel through the line to move the air bubble past = the high part of the loop. =20 =20 Could something like this be happening on our planes? Since we are = running out of things to check, I am going to take a close look the next = time I have the cowl off. =20 Steve Legacy IO-550 =20 Your comment regarding the air is interesting. I don't believe we have = any=20 air in any of the fuel lines but maybe I should look harder at this=20 possibility. =20 Thanks for your input. =20 Sent from my iPad Berni Breen Bbreen@cableone.net ------=_NextPart_000_00A2_01CC2E8E.CCFE8DD0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Berni,

 

My experience with an Aircoupe was enlightening.=C2=A0 I found the = source of the problem to be a loop (imagine an inverted U) that trapped = air, not fuel vapor, in a section of fuel line.=C2=A0 When the fuel = valve was closed and the lines between the valve and carburetor were = drained, an air bubble would trap in the high section of the loop when = the valve was reopened.=C2=A0 On takeoff the high fuel flow would push = some of the air to the Gascolator where it trapped at the screen.=C2=A0 = Engines were quitting on takeoff and many times the bubble would get = enough agitation on the hard landing to work though leaving no evidence = in the glass bowl.=C2=A0 It was a faulty design later addressed by = Service Letter.=C2=A0 A temporary fix was to force a high flow of fuel = through the line to move the air bubble past the high part of the = loop.=C2=A0

 

Could something like this be happening on our planes?=C2=A0 Since we = are running out of things to check, I am going to take a close look the = next time I have the cowl off.

 

Steve=C2=A0=C2=A0 Legacy=C2=A0 IO-550
  Your comment regarding the air is interesting.  I don't = believe we have any
air in any of the fuel lines but maybe I should = look harder at this
possibility.
 
 Thanks for your = input.
 
 Sent from my iPad
 Berni = Breen
 Bbreen@cableone.net


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