X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao105.cox.net ([68.230.241.41] verified) by logan.com (CommuniGate Pro SMTP 5.2.6) with ESMTP id 3068864 for flyrotary@lancaironline.net; Sat, 09 Aug 2008 14:32:12 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.41; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao105.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20080809183131.NHMF774.fed1rmmtao105.cox.net@fed1rmimpo03.cox.net> for ; Sat, 9 Aug 2008 14:31:31 -0400 Received: from BigAl ([72.192.137.74]) by fed1rmimpo03.cox.net with bizsmtp id 0JXX1a00A1cVYgg04JXXwh; Sat, 09 Aug 2008 14:31:31 -0400 From: "Al Gietzen" To: "Rotary motors in aircraft" Subject: Fuel pressure Date: Sat, 9 Aug 2008 11:32:38 -0800 Message-ID: <000001c8fa56$aebecb10$6401a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C8FA13.A09B8B10" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C8FA13.A09B8B10 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Somewhere during my trip a few weeks ago, I had noted that the engine = seemes to be running a bit rich from where I had set it. I then noted that the fuel pressure was reading high - like about 48 -49 psi; and I have the regulator set for 40 psi at WOT. Not know what else to try, I switched = from pump 1 to pump 2. After a bit the pressure was back to normal; and = worked fine after that. =20 My thought later was that switching the pumps should have nothing to do = with it. The two pumps are in parallel, then the filter, then the pressure sensor, then the fuel rail with the regulator on the end, bypassing back = to the tank. =20 Last week on a short flight I noted the fuel pressure bar on the EM2 at = the max and blinking. The readout was 50 psi. I watched for a short while nothing changed; then switched pumps. Nothing changed right away, but = the pressure slowly returned to normal. Then running pump1, both pumps, or = pump 2 didn't make any difference. =20 I discussed with the expert at TWM (the maker of the pressure regulator) = and after some discussion, he was completely at a loss as to what could = cause the pressure regulator to act in that fashion. It is a MAP referenced regulator, and the MAP readout was as it should be. =20 I'm baffled. =20 Al ------=_NextPart_000_0001_01C8FA13.A09B8B10 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Somewhere during my trip a few weeks ago, I had = noted that the engine seemes to be running a bit rich from where I had set = it. I then noted that the fuel pressure was reading high – like about 48 = -49 psi; and I have the regulator set for 40 psi at WOT. Not know what else to = try, I switched from pump 1 to pump 2. After a bit the pressure was back to = normal; and worked fine after that.

My thought later was that switching the pumps = should have nothing to do with it. The two pumps are in parallel, then the = filter, then the pressure sensor, then the fuel rail with the regulator on the = end, bypassing back to the tank.

Last week on a short flight I noted the fuel = pressure bar on the EM2 at the max and blinking. The readout was 50 psi. I watched = for a short while nothing changed; then switched pumps. Nothing changed = right away, but the pressure slowly returned to normal. Then running pump1, = both pumps, or pump 2 didn’t make any difference.

I discussed with the expert at TWM (the maker of = the pressure regulator) and after some discussion, he was completely at a = loss as to what could cause the pressure regulator to act in that fashion. = It is a MAP referenced regulator, and the MAP readout was as it should = be.

I’m baffled.

Al

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