X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 09 May 2008 13:48:24 -0400 Message-ID: X-Original-Return-Path: Received: from mta16.adelphia.net ([68.168.78.211] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2914884 for lml@lancaironline.net; Fri, 09 May 2008 08:52:26 -0400 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.211; envelope-from=glcasey@adelphia.net Received: from [76.89.163.133] by mta16.adelphia.net (InterMail vM.6.01.05.04 201-2131-123-105-20051025) with ESMTP id <20080509125129.LDGR11947.mta16.adelphia.net@[76.89.163.133]> for ; Fri, 9 May 2008 08:51:29 -0400 Mime-Version: 1.0 (Apple Message framework v753) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-70-102068924 X-Original-Message-Id: <342120E2-5D1C-4DF2-A199-554B7A613AA1@adelphia.net> From: Gary Casey Subject: Re: Lancair 320 low fuel pressure X-Original-Date: Fri, 9 May 2008 05:51:42 -0700 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.753) --Apple-Mail-70-102068924 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed For years I flew a Cherokee 180 that had a similar problem. When going high, above 8,000 feet and especially when the outside temperature was warm, the fuel pressure would gradually drop to about 2 psi. At low altitude it would be in the high end of the green and at high altitude the low end of the green. I could never come up with an explanation and the condition didn't change with a new fuel pump. It would rise slightly when turning on the electric pump. I doubt that it is a tank vent problem, but I have no likely explanations. Never caused a problem, but always bothered me. I always wondered if it was something to do with the way the gage read the pressure, but that didn't make sense either. Gary Casey > > I normally have had around 4-6 psi flying around my airport, however, > yesterday, I flew on my first cross country. Cruising at 220mph, I > noticed my > fuel pressure slowly start to drop as I got faster and higher. It > went down > to 2 psi. I climbed higher in case I needed time to find a place to > land. > Luckily I didn't. > > I turned on my fuel pump with only a slight increase of 1 psi as a > result. > I switched tanks and same results. > > I learned my engine requires .5 psi minimum so I have remained > about that, > however I don't like it. I want 4-6 to keep my peace of mind. Top > psi limit > is 8. > > So, I asked around to a couple A&P's. They all think it could be my > vent on > the tanks is not providing enough positive pressure in the tanks. I > thought > of maybe increasing or decreasing the angle of the vent into the > relative wind > to increase the fuel positive pressure in my tanks, however I know > it is bad > to have too much pressure in the tanks as well. > > So, I am seeking input on this problem or if you guys think I > shouldn't even > worry about it. > > Interesting that when I reduced power and got into my pattern, the > psi went > up to 5 psi. > > Matt Reeves --Apple-Mail-70-102068924 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 For years I flew a Cherokee 180 that had a similar problem. =A0When = going high, above 8,000 feet and especially when the outside temperature = was warm, the fuel pressure would gradually drop to about 2 psi. =A0At = low altitude it would be in the high end of the green and at high = altitude the low end of the green. =A0I could never come up with an = explanation and the condition didn't change with a new fuel pump. =A0It = would rise slightly when turning on the electric pump. =A0I doubt that = it is a tank vent problem, but I have no likely explanations. =A0Never = caused a problem, but always bothered me. =A0I always wondered if it was = something to do with the way the gage read the pressure, but that didn't = make sense either.
Gary Casey

I normally have had around 4-6 psi flying = around my airport, however,
yesterday, I flew on my first cross = country. Cruising at 220mph, I noticed my
fuel pressure slowly start = to drop as I got faster and higher. It went down
to 2 psi. I = climbed higher in case I needed time to find a place to land.
= Luckily I didn't.

I turned on my fuel pump with only a = slight increase of 1 psi as a result.
I switched tanks and same = results.

I learned my engine requires .5 psi minimum so I = have remained about that,
however I don't like it. I want 4-6 to = keep my peace of mind. Top psi limit
is 8.

So, I asked = around to a couple A&P's. They all think it could be my vent on =
the tanks is not providing enough positive pressure in the tanks. = I thought
of maybe increasing or decreasing the angle of the vent = into the relative wind
to increase the fuel positive pressure in my = tanks, however I know it is bad
to have too much pressure in the = tanks as well.

So, I am seeking input on this problem or if = you guys think I shouldn't even
worry about it.

= Interesting that when I reduced power and got into my pattern, the psi = went
up to 5 psi.

Matt = Reeves

= --Apple-Mail-70-102068924--