Return-Path: Received: from [199.185.220.240] (HELO priv-edtnes46.telusplanet.net) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 726991 for flyrotary@lancaironline.net; Sun, 13 Feb 2005 05:49:52 -0500 Received-SPF: pass receiver=logan.com; client-ip=199.185.220.240; envelope-from=haywire@telus.net Received: from Endurance ([207.81.25.155]) by priv-edtnes46.telusplanet.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with SMTP id <20050213104906.QIKE289.priv-edtnes46.telusplanet.net@Endurance> for ; Sun, 13 Feb 2005 03:49:06 -0700 From: "Todd Bartrim" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Vapor lock in sump/header tank. Date: Sun, 13 Feb 2005 02:48:30 -0800 Message-ID: <000f01c511b9$8f447f20$0201a8c0@Endurance> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0010_01C51176.81213F20" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook CWS, Build 9.0.2416 (9.0.2910.0) Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0010_01C51176.81213F20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hi Paul; I was going to ask you to draw a detailed sketch of your system to ensure that we are all on the same page while trying to diagnose your problems, but your latest description along with the photo makes it pretty clear. However it wouldn't hurt to have a good drawing. I'm very happy without a header tank but I feel that you could make a sump tank work for you by simply adding the vents. I'd use a 3/8" line from the top of your sump going to a "T" then on to the very top of both wing tanks. Do not just tie this into your existing main tank vent lines. Any flow up this line would flow to the tank in use as it would be drawing fuel out. I would expect that fuel would fill this line to equalize the level in the main tank as what you would have created would be a "U" tube manometer, however any vapour that appeared in the sump tank should flow up the vent line to the mains. I'd use a 3/8" line rather than a 1/4" line for the vent as there is a chance that there could be enough surface tension of fuel inside a smaller vent line to impede flow. Since you still have the Facet pump in the feed line from the mains to the sump you can always turn that on at critical flight phase to ensure circulation, forcing any possible vapours back to the main tanks. This should be all that is needed to make your sump tank work. However it may be less work to just get rid of the sump tank. I don't know how hard it will be for you to add return lines to your mains? Either way it should be done, whether you are using them to return fuel or to vent your sump tank. Since you only use 2 tanks you can buy a duplex valve that switches feed and return flows ($$$$), that would help to manage this. I didn't go with this route since I have 6 tanks to manage. Tracy method is also another possibility and several others are using it. I didn't go this route just because I didn't really like the idea of only having one source and having to keep transferring fuel on a regular basis. But there really is nothing wrong with it and it definitely is less workload than the fuel management that I did when I had the header system. My system isn't a true returnless system as found in late model cars, as that is designed to have only one main tank however it is as close as I could make it. Rather than adding unnecessarily to the archives I'll just add the link to the original post and drawing. http://lancaironline.net/lists/flyrotary/Message/10078.html?Language= It has been working great for me, but my needs were a little different as I am managing 6 tanks. With only two tanks to manage I would seriously consider using a conventional fuel return system with a duplex valve and no sump tank. You will also be shaving off a few more precious pounds by ridding yourself of it. Todd (I might as well only have one tank for all the flying I have time for lately) ------=_NextPart_000_0010_01C51176.81213F20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi=20 Paul;
    I was going to ask you to draw a detailed = sketch of your=20 system to ensure that we are all on the same page while trying to = diagnose your=20 problems, but your latest description along with the photo makes it = pretty=20 clear. However it wouldn't hurt to have a good = drawing.
    I'm very happy without a header tank but I feel = that you=20 could make a sump tank work for you by simply adding the vents. I'd use = a 3/8"=20 line from the top of your sump going to a "T" then on to the very top of = both=20 wing tanks. Do not just tie this into your existing main tank vent = lines. Any=20 flow up this line would flow to the tank in use as it would be drawing = fuel out.=20 I would expect that fuel would fill this line to equalize the level in = the main=20 tank as what you would have created would be a "U" tube manometer, = however any=20 vapour that appeared in the sump tank should flow up the vent line to = the mains.=20 I'd use a 3/8" line rather than a 1/4" line for the vent as there is a = chance=20 that there could be enough surface tension of fuel inside a smaller vent = line to=20 impede flow. Since you still have the Facet pump in the feed line from = the mains=20 to the sump you can always turn that on at critical flight phase to = ensure=20 circulation, forcing any possible vapours back to the main tanks. This = should be=20 all that is needed to make your sump tank work.
    However it may be less work to just get rid of = the sump=20 tank. I don't know how hard it will be for you to add return lines to = your=20 mains? Either way it should be done, whether you are using them to = return fuel=20 or to vent your sump tank. Since you only use 2 tanks you can buy a = duplex valve=20 that switches feed and return flows ($$$$), that would help to manage = this. I=20 didn't go with this route since I have 6 tanks to manage. Tracy method = is also=20 another possibility and several others are using it. I didn't go this = route just=20 because I didn't really like the idea of only having one source and = having to=20 keep transferring fuel on a regular basis. But there really is nothing = wrong=20 with it and it definitely is less workload than the fuel management that = I did=20 when I had the header system.
    My system isn't a true returnless system as = found in late=20 model cars, as that is designed to have only one main tank however it is = as=20 close as I could make it. Rather than adding unnecessarily to the = archives I'll=20 just add the link to the original post and = drawing.
 =20 http://lancaironline.net/lists/flyrotary/Message/10078.html?Language= =3D  =20
It has=20 been working great for me, but my needs were a little different as I am = managing=20 6 tanks. With only two tanks to manage I would seriously consider = using a=20 conventional fuel return system with a duplex valve and no sump tank. = You will=20 also be shaving off a few more precious pounds by ridding yourself of=20 it.
 
Todd    (I might as well only have one tank for = all the=20 flying I have time for lately)
 
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