Return-Path: Received: from [65.33.165.140] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 4.3c1) with HTTP id 726513 for flyrotary@lancaironline.net; Sat, 12 Feb 2005 15:17:14 -0500 From: "Marvin Kaye" Subject: Re: [FlyRotary] Re: Vapor lock To: "Rotary motors in aircraft" X-Mailer: CommuniGate Pro WebUser Interface v.4.3c1 Date: Sat, 12 Feb 2005 15:17:14 -0500 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Lots of approaches have been taken to keep fuel from backing up the vent lines. Some folks with low wing aircraft have taken the approach of running the vents from the outboard end of the wing tank back into the fuselage, looped up over the cockpit ceiling and then down to the belly. The vent pipe sticking out of the belly is either tilted slightly forward into the windstream or perfectly vertical with the end cut at a 45* angle facing into the slipstream to add a modicum of pressure to the tank to improve feeding. The cross-back routine works really well at keeping the vents from dumping fuel when the airplane is parked on an incline that raises one wingtip above the other, as the vent line is never able to dump fuel. Another approach for airplanes with winglets is to run the vent line up into the winglet and terminate it in a mini-NACA duct on the high pressure side of the winglet... this would be a great method for you canard guys, and I'd be surprised if that wasn't the currently accepted method. Venting hi-wing aircraft introduces the limitation of not being able to get the vent line any higher than the highest point the upper wing skin reaches dues to dihedral. For my way of thinking, venting a low wing fuel system offers lots more possibilities for success. Again, just some observations. "Paul" : """ Hi, Al....my concern was this....what if fuel is (for some reason?) forced back up through the vent line? I would rather it went back into one of the tanks than along the top of the fuselage towards my exhaust. Please don't ask me why fuel might be forced back up through the vent line....I don't have a good enough understanding of the system, only reports from others that they had fuel come out of their vent line. Paul Conner """