Return-Path: Received: from tomcat.al.noaa.gov ([140.172.240.2] verified) by logan.com (CommuniGate Pro SMTP 4.3c3) with ESMTP id 883966 for flyrotary@lancaironline.net; Tue, 19 Apr 2005 16:50:22 -0400 Received-SPF: none receiver=logan.com; client-ip=140.172.240.2; envelope-from=bdube@al.noaa.gov Received: from mungo.al.noaa.gov (mungo.al.noaa.gov [140.172.241.126]) by tomcat.al.noaa.gov (8.12.11/8.12.0) with ESMTP id j3JKncpa027031 for ; Tue, 19 Apr 2005 14:49:38 -0600 (MDT) Message-Id: <6.2.1.2.0.20050419144034.038513b8@mailsrvr.al.noaa.gov> X-Mailer: QUALCOMM Windows Eudora Version 6.2.1.2 Date: Tue, 19 Apr 2005 14:49:19 -0600 To: "Rotary motors in aircraft" From: Bill Dube Subject: Re: [FlyRotary] Re: Fuel return to tank In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/html; charset="us-ascii" Essentially the same height of fuel. Thus, essentially the same back pressure. Two feet of fuel would be less than 1 psi, regardless.

Traditionally, you dump the return at the top of the tank. You can see (and sometimes hear) the return working. It helps mix up the fuel. It also makes it is easier to work on the return line. A leak in the return line while the vehicle is parked is less of a catastrophe.

I can't think of any advantage of plumbing it to the bottom of the tank. I suppose when the tank is near empty the back pressure would be less for the bottom return, but the difference would be a fraction of a psi. Not enough to notice.

At 12:19 PM 4/19/2005, you wrote:

Rusty, I believe returning to the bottom will create slight back pressure on the pump and the possibilities of fuel siphoning out if there is a leak in the system?
Buly

I thought about that Buly, but since his tank is 2 foot tall, raising the fuel all the way to the top to return it will add some backpressure too. As for leaks, just depends on where it is. Since most of the fuel system is sitting in his lap, I'm guessing he'll catch most leaks right away :-0