Return-Path: Received: from imf18aec.mail.bellsouth.net ([205.152.59.66] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 726406 for flyrotary@lancaironline.net; Sat, 12 Feb 2005 14:11:37 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.66; envelope-from=sqpilot@bellsouth.net Received: from [209.214.45.129] by imf18aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050212191049.XIZT2060.imf18aec.mail.bellsouth.net@[209.214.45.129]> for ; Sat, 12 Feb 2005 14:10:49 -0500 Received: from 127.0.0.1 (AVG SMTP 7.0.300 [265.8.7]); Sat, 12 Feb 2005 13:10:38 -0600 Message-ID: <005c01c51136$88e91510$812dd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Header Tanks, Venting & Pressure Reg Position was Re: [FlyRotary] Re: Vapor lock Date: Sat, 12 Feb 2005 13:10:37 -0600 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original Hi, Leon....thank you again for going into such great detail regarding our fuel systems. Fortunately, it sounds like I did about 90% of the installation correct....My two main tanks are higher than the sump tank, and the two fuel pumps are lower than the sump tank, and they both have one-way valves in them. It looks like the primary item I missed is running a vent from the sump tank to one of the main tanks. Not too difficult....I think I can slip into the back seat and weld a 1/4npt bung onto the aluminum header tank if I keep it full of fuel. (I am only kidding about welding the tank full of fuel, you can come back off the ceiling now). On a serious note, it would not be all that difficult to remove the sump tank and bring it to our local welder who will fill it with nitrogen or water or ??? and weld on a 1/4NPT bung on top. I can then run a piece of 1/4" aluminum tubing back up to one of the main tanks. I also will be installing fire sleeve over the fuel line that goes from the EFI fuel pump, over the top of the engine and into the fuel rail. Can't hurt. Thanks again for taking the time to assist me, Leon and so many others. What a great forum we have here....people helping people. Thanks again. A very appreciative Paul Conner ----- Original Message ----- From: "Leon" To: "Rotary motors in aircraft" Sent: Saturday, February 12, 2005 8:48 AM Subject: [FlyRotary] Header Tanks, Venting & Pressure Reg Position was Re: [FlyRotary] Re: Vapor lock > Hi Guys, > > PRESSURE REG POSITION > > Paul's installation is correct. The regulator MUST be on the RETURN side > of > the fuel rail. Otherwise, it can't regulate the pressure!! The > regulator > has to be able to dump excess pressure overboard to the fuel return, and > the absolutely critical thing is that it must be able to keep the pressure > drop across the injectors constant > as the MAP (Manifold Absolute Pressure) varies. (otherwise you can't meter > the fuel accurately) > > HIGH PRESSURE PUMP POSITION > > Ideally, the pressure pump(s) should be below the header/surge tank > level. > They do not like sucking fuel up hill, especially when an aircraft is > climbing at a steep angle - you are just asking for trouble. In drag > cars, > the pump is always positioned BEHIND the surge tank because the gravity > vector is rearward, just like a climbing aircraft (which is when you need > the most fuel!!). > > A word of warning. With a header tank at the front in a steep climb, I > can > see a situation where a gravity fed header/surge tank could cease to be > filled. Auxillary lift/boost pumps then become necessary. Think about > that > one ... > > ONE WAY VALVES > > If you are running two high pressure pumps, and normally only use one for > cruise (but both for take-off), they should have one way valves in front > of > them. Otherwise, you won't get full pressure to the rail and the > regulator. The fuel will just reflux around back through the T piece to > the > stationary pump and back into the header/surge tank. Some pumps do have > one > way valves in them as standard - easy to check before fitting - just blow > through the outlet. > > Additionally, the idea of continually circulating fuel from the fuel rail > via the return line is to prevent vapour > lock from heat soak in the fuel rail. All this is settled technology, > and > has been around and working perfectly well, in millions and millions of > EFI > cars, for over 20 > years. I continue to be flummoxed as to why Experimental aircraft people > are always trying to re-invent the wheel un-necessarily and cause > themselves > grief? Just copy what is known to work ... > > RETURN LINES AND VENTING > > Finally, with the use of a header/surge/auxillary tank, it MUST be > vented. > The correct way to do it is to have the return line from the pressure reg > return to the side of the header/surge tank near the top. Another line is > then returned from the very TOP of the header/surge tank to the main tank > (the idea is to be able to purge any air/vapour). This way, the > header/surge tank is vented via the main fuel tank(s), and the header > tank > always remains full. > > The only caveat on this is obviously if you have multiple main tanks (one > or > more in each wing), the return lines to the tanks must be switchable. > Otherwise as you pump fuel out of either (any of the) tank(s), and IF it > always goes back to the one tank, it will overflow pretty quickly. The > return line must therefore go back to the tank that is being used as the > supply tank. CRITICAL if a lift/boost pump is being used to feed the > header/surge tank. > > Yeah, ... Yeah, ... I know, ... I know, ... some of you will say that you > do it differently and it works for you. Jolly good! I'm really happy for > you. However, all of the above has all been figured out in long > distance/endurance rally/off road racing cars with multiple tanks many > years > ago. So please guys, don't go and try to re-invent settled technology - > you > will only cause yourelves heartache, and it's all liable to end in tears. > > Cheers, > > Leon > > > > > ----- Original Message ----- > From: "Paul" > To: "Rotary motors in aircraft" > Sent: Saturday, February 12, 2005 6:39 AM > Subject: [FlyRotary] Re: Vapor lock > > >> >> ----- Original Message ----- >> From: "Ernest Christley" >> To: "Rotary motors in aircraft" >> Sent: Friday, February 11, 2005 12:24 PM >> Subject: [FlyRotary] Vapor lock >> >> >> > I'm not sure that I understand vapor lock completely. Is the problem >> > that the fuel gets hot, or that the fuel boils and then the pumps no >> > longer work? >> > >> > I have a plan for a stone cold simple fuel system. With only one tank >> > positioned high, I plan to put both fuel pumps directly under the tank >> > which is located behind the cabin (tractor configuration). Position >> > the >> > fuel regulator beside the pump, and I will only having a single line >> > running out to the engine compartment. Think of it as one LONG header. >> > The issue will be that the fuel will not 'circulate'. What goes out to >> > the header at the engine will stay there till it gets used. >> > >> > Is this a prescription for 'vapor lock', or will any boiling fuel >> > simply >> > get blown through the injectors? >> > >> Hi, Ernest....I might have it wrong, but I seem to recall that I was told > to >> put the fuel pressure regulator just AFTER the injectors/fuel rail. >> That's >> what I did...maybe that's part of my problem? Paul Conner >> >> >> -------------------------------------------------------------------------- > ------ >> >> >> >> >> >> >> -------------------------------------------------------------------------- > ------ >> >> >> >>> Homepage: http://www.flyrotary.com/ >> >>> Archive: http://lancaironline.net/lists/flyrotary/List.html >> > >> >> >> -------------------------------------------------------------------------- > ------ >> >> >> No virus found in this incoming message. >> Checked by AVG Anti-Virus. >> Version: 7.0.300 / Virus Database: 265.8.7 - Release Date: 2/10/2005 >> >> >> >> >> -- >> No virus found in this outgoing message. >> Checked by AVG Anti-Virus. >> Version: 7.0.300 / Virus Database: 265.8.7 - Release Date: 2/10/2005 >> >> >> >> Homepage: http://www.flyrotary.com/ >> >> Archive: http://lancaironline.net/lists/flyrotary/List.html >> > > >>> Homepage: http://www.flyrotary.com/ >>> Archive: http://lancaironline.net/lists/flyrotary/List.html > > > -- > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.300 / Virus Database: 265.8.7 - Release Date: 2/10/2005 > > -- No virus found in this outgoing message. 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