X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from fed1rmmtao103.cox.net ([68.230.241.43] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1908111 for flyrotary@lancaironline.net; Wed, 07 Mar 2007 19:58:14 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.43; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao103.cox.net (InterMail vM.7.05.02.00 201-2174-114-20060621) with ESMTP id <20070308005727.UNNR3546.fed1rmmtao103.cox.net@fed1rmimpo01.cox.net> for ; Wed, 7 Mar 2007 19:57:27 -0500 Received: from BigAl ([72.192.132.90]) by fed1rmimpo01.cox.net with bizsmtp id Y0xT1W0041xAn3c0000000; Wed, 07 Mar 2007 19:57:27 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Fuel tank vent Date: Wed, 7 Mar 2007 16:57:33 -0800 Message-ID: <000001c7611c$c171aea0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C760D9.B350B890" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C760D9.B350B890 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable In a fuel injected engine such as the 13B you need enough for the engine plus the fuel that is returned to the tank. Also unless aggressively leaned the rotary will burn a bit more fuel for = the power delivered so that will also increase fuel flow requirements a = little. I assume we are talking about the fuel tank vent. No need for vent air = for fuel that is returned to the tank; only for net outflow. Anything much bigger than a pinhole will allow enough airflow to compensate for fuel = flow out since the viscosity of air is many times less than fuel. But it = doesn=92t hurt to have a bit more, and use a readily handy =BC=94 aluminum tube. = I have about 3=92 of =BC=94 aluminum vent line, and I know that it will allow = more than 30 GPH. That was tested with gravity feed of fuel through a 3/8=94 = line, and I=92m quite certain that the limiting factor was the fuel through the = 3/8=94 line. =20 FWIW, =20 Al G ------=_NextPart_000_0001_01C760D9.B350B890 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

In a fuel injected engine such as the 13B you = need enough for the engine plus the fuel

that is returned to the = tank.

Also unless aggressively leaned the rotary = will burn a bit more fuel for the power delivered so that will also increase fuel = flow requirements a little.

I assume we are talking about the = fuel tank vent.=A0 No need for vent air for fuel that is returned to the = tank; only for net outflow.=A0 Anything much bigger than a pinhole will allow = enough airflow to compensate for fuel flow out since the viscosity of air is many times = less than fuel.=A0 But it doesn’t hurt to have a bit more, and use a = readily handy =BC” aluminum tube.=A0 I have about 3’ of =BC” = aluminum vent line, and I know that it will allow more than 30 GPH.=A0 That was tested = with gravity feed of fuel through a 3/8” line, and I’m quite = certain that the limiting factor was the fuel through the 3/8” = line.

FWIW,

Al G

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