X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-pg0-f48.google.com ([74.125.83.48] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9592083 for flyrotary@lancaironline.net; Tue, 21 Mar 2017 09:23:51 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.83.48; envelope-from=ceengland7@gmail.com Received: by mail-pg0-f48.google.com with SMTP id 21so60687953pgg.1 for ; Tue, 21 Mar 2017 06:23:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=DtL0HxweCVv4JGZQBQkHB2F4lWD1DEQDN4X5SbXMMS4=; b=mGRSuOy65zRK8Paa3Q/oeK2Ru+TZ2mrg28oJQ9Nb62Cfi16RrnQUJKRvX2q9izHz0i QaL8ZupKAu3k78yol3HB16xvHgE69q9uwUUOh1458PRoyY/D64lFPbt0b7UEpeIlFTHQ 8y6ZU9jys+tOTfAJJ5xmnQwJpjbNI2O8IbGSp5bgjx1J9bZdXCLBsNYS0kUArputP0Wj l7U9FWQGzKyEuHzQOW1BqTcUtzKsyQb5D58g34zTCggMFU5I2Xn7mZwnL5Xv9jreA1gk 7JoHEpkurYEpGBYrSS9WU7O96HLFdFM7iH5wckBoHImzBu9V/kNbD2iojVFfsy/Vr2ca 5V2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=DtL0HxweCVv4JGZQBQkHB2F4lWD1DEQDN4X5SbXMMS4=; b=Uq2WwSBjEHhOaOfRkiuobjiqQiivReDS3cBXIo+876NgPgCnEVUgjmoMm3bgayuS4f RSELa8QPAP/OLfT921p+CrtVhWIcxNDxEkKdp6HI2DwOUjb8WpDbI8DH40UboEboBM09 Ff0huJ3oEYZoDfRv1GVmOBFoNsrq2/149ozMXXy1eMm31xDQodXM/Lx9S/tp1tSc+gJz cyQyYey1IvBP9wr4fT4m3/zdSoyhBFP0lX7a3DxH3daaVDTodK6M2+rVYbwjURgcmh92 IaEyHtNRazkFLmpcyttgV+o3oUW+gUdunZHd0xk0tFV4IDBqP7Cnpg4zy3UgE05YkF0I 853w== X-Gm-Message-State: AFeK/H21bQOSGW+XS6zDeT2ocAAzmOFWkuB7u7QWRjfv3P1OZHOVQByACd19ogcirS2G9ydCR11XNe5nziAUiw== X-Received: by 10.99.173.6 with SMTP id g6mr36379213pgf.75.1490102612324; Tue, 21 Mar 2017 06:23:32 -0700 (PDT) MIME-Version: 1.0 Received: by 10.100.128.83 with HTTP; Tue, 21 Mar 2017 06:23:29 -0700 (PDT) In-Reply-To: References: Date: Tue, 21 Mar 2017 08:23:29 -0500 Message-ID: Subject: Re: [FlyRotary] Re: fuel system peer review To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=94eb2c1bef26e2f419054b3d8c2e --94eb2c1bef26e2f419054b3d8c2e Content-Type: text/plain; charset=UTF-8 Well, I already have the combination regulator return/transfer port in the tank, and the line is already in place in the plane. So modding the plane won't be an issue, though I am lucky enough that I can walk down the hill from my house to my (fairly well tooled up) hangar. Steve, if it's easy for you to test my proposed layout, that would be great, but don't spend time on it if you're busy. I'd do it myself before I fly the plane, anyway. Anyone see any issue with 'T'ing the transfer & regulator returns together? It's a -6 line, so flow shouldn't be an issue. I'm willing to live with the risk of a clogged vent. If a vent clogs, I'll be coming down faster from fuel starvation than from over pressurizing the tank. :-) Charlie On Tue, Mar 21, 2017 at 12:52 AM, Steven W. Boese < flyrotary@lancaironline.net> wrote: > Charlie, > > I also would encourage you to consider transferring fuel directly into the > main tank. It is unlikely that the high pressure pump used as a transfer > pump will be able to pump air against the ~40 psi head pressure in the rail > when an auxiliary tank runs dry. So you probably would not have the engine > stumble then. But to be able to transfer fuel by selecting another tank, > the air would need to be purged from the transfer pump to get it working > again. This could be done by shutting the normally running injection pump > off until the rail pressure dropped enough that the air in the transfer > pump could be purged through the injectors. This might require more than > just a stumble. The engine would need to be turning (probably windmilling > at cruise speeds) so the fuel injectors would be active. > > My fuel system has only the two wing tanks. It initially used a low > pressure Facet pump to transfer fuel. I didn't like the low flow rate of > that pump. So I replaced it with a third high pressure injection pump. > That worked well but the possibility of developing more than 40 psi in the > wing tank in case of a vent malfunction bothered me. The tank would most > likely fail at pressures much less than this. So I ended up with a duplex > valve and returning fuel to the selected tank. A homemade duplex valve was > used for several years while I saved up the $ for the Andair valve. This > was a solution for me since I just had the two tanks to deal with. > > I still have the extra injection pump and will set up a transfer system > like you propose on my test stand just out of curiosity since what makes > sense to me may not be how the actual system behaves. > > Steve Boese > > On Mar 20, 2017, at 10:12 PM, Todd Bartrim > wrote: > > If I was going to go with the transfer fuel plan I would just have a > separate inlet port into the main tank. That would eliminate any chance of > air getting into the system. > I once had a very complicated fuel system as I have 6 tanks (inboard > main, outboard auxiliary, wingtip aux-auxiliary) and I figured going to a > common header tank would simplify things. But it was prone to vapour lock. > But I had a solution for that which created another issue, which i had > another solution for, etc. Things got very complex. > Even when it was perfect on the ground I had several engine outs when in > flight during my test period due to vapor lock or air. > Managing 6 tanks is always going to be more complex, but I simplified it a > lot by going to a return-less system (deadheaded) like you are proposing. > It worked well and eliminated all issues. > During my current rebuild I modified this again, but mostly just to clean > it up as when I first modified it I was at the airport where I didn't have > the shop resources that I have now. > Most modern vehicles now use a returnless system for emissions > requirements so this is nothing new, so I think your plan to deliver fuel > from the main tank is simple and reliable. I would just change the transfer > line. Even if it seems like more work, it will be worth it because if you > don't do it now while you are at home in your shop, then if later you find > out you need to do it after you are at the airport you will be cussing. > Unless you are one of those lucky SOBs that have a fully equipped private > hangar! But still it is easier to do it while building. > If you are determined to try it with the transfer plumbed into the > delivery line, then at least install an inlet port with a cap in the main > tank so that it will be easy to change later. This is probably the best > course of action, as then you get to experiment which is what we're doing > here, but have an easy fallback to planB. > > On Mon, Mar 20, 2017, 11:06 PM Charlie England < > flyrotary@lancaironline.net> wrote: > >> Hi Andrew, >> >> I get you on the 'complicated system' issue. That's one reason I'm >> considering this idea. And if I had any way to set up a gravity fed sump >> for the aux tanks, I'd eliminate the aux tank selector valve. :-) >> >> Yeah, pumping air is the big vulnerability. If I go down this path, I'll >> definitely include a GEM optical sensor ahead of the transfer pump(s). I'll >> also do some 'pumping air' testing. One in-tank injection pump will be >> running during any transfer operation, so testing will determine whether >> air from the xfer pump will cause engine stoppage, or just a stumble. >> >> Thank you for the input. Anybody else? I'm not married to this, but I am >> giving it serious consideration. >> >> >> Charlie >> >> >> On 3/20/2017 8:51 PM, Andrew Martin wrote: >> >> Charlie, I think that would work. probably better to re-route the lines >> though, so fuel from Aux tanks naturally wants to go through the regulator >> rather than to the fuel rail. eventually you will leave a transfer pump on >> and suck air. >> In effect you've got 4 efi pumps, maybe just a little bit extreme, >> especially if someone turns them all on. >> >> Andrew >> (currently replacing entire fuel system from tanks to rail. previous just >> too complex and heavy. sump tank, 2 pumps & 4 valves are coming out) >> >> On Tue, Mar 21, 2017 at 5:26 AM, Charlie England < >> flyrotary@lancaironline.net> wrote: >> >> 1st, let me define my delivery architecture. I like Tracy's idea of >> feeding the engine from one tank, and transferring aux tanks to the main >> tank. I understand the downside of being unable to switch tanks, but many >> a/c (including turbines) supply from one tank, so that's my choice. It >> avoids the need for a duplex fuel selector, which I like. Effectively, I >> have 3 'aux' tanks, and I'm using the stock (3 inlet) Van's RV fuel >> selector to feed redundant transfer pumps in parallel. >> >> I know that most have a separate return port in their tank(s) for >> regulator return. With my need for aux transfer, my original plan was to >> 'T' the aux transfer line into the regulator return line, which I'm pretty >> sure has been done before. >> >> I'm currently working on installing both injection pumps in the fuel >> tank, conceptually similar to standard auto practice for the last couple of >> decades: no risk of vapor lock with the added bonus of a very clean >> installation. The regulator will be in the wingroot, just outside the tank, >> with the manifold pressure line running to that location for pressure >> control. (Deadheading fuel to the fuel rail has been done on both cars and >> a/c successfully; I believe it's an option on the new SDS system being >> marketed to Lyc drivers now.) >> >> The recent thread on fuel pressure changes while running both injection >> pumps got me thinking. If it's typical to see only a couple of PSI change >> when running both pumps, has anyone considered running the transfer line >> into the regulator? The reason I'm considering this is twofold. It provides >> a 'final option' for short term fuel delivery if both injection pumps are >> lost, and, because the regulator is in the wingroot, I would need to run >> only one fuel line to the supply tank. >> >> I'll be using gerotor style transfer pumps (positive displacement) and >> the aux selector has an 'off' position, so backflow won't be an issue. >> >> A quick & dirty sketch is attached, diagramming the idea. >> >> There would never be more than 2 pumps running at any time, since >> transfers would only happen in cruise flight. Can anyone poke holes in this >> arrangement? >> >> Charlie >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: http://mail.lancaironline. >> net:81/lists/flyrotary/List.html >> >> >> >> --94eb2c1bef26e2f419054b3d8c2e Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Well, I already have the combination regulator return/tran= sfer port in the tank, and the line is already in place in the plane. So mo= dding the plane won't be an issue, though I am lucky enough that I can = walk down the hill from my house to my (fairly well tooled up) hangar.=C2= =A0

Steve, if it's easy for you to test my proposed = layout, that would be great, but don't spend time on it if you're b= usy. I'd do it myself before I fly the plane, anyway.

Anyone see any issue with 'T'ing the transfer & regulat= or returns together? It's a -6 line, so flow shouldn't be an issue.= I'm willing to live with the risk of a clogged vent. If a vent clogs, = I'll be coming down faster from fuel starvation than from over pressuri= zing the tank. :-)

Charlie

On Tue, Mar 21, 2017 at 12:= 52 AM, Steven W. Boese <flyrotary@lancaironline.net> wrote:
Charlie,

I also would encourage= you to consider transferring fuel directly into the main tank.=C2=A0 It is= unlikely that the high pressure pump used as a transfer pump will be able = to pump air against the ~40 psi head pressure in the rail when an auxiliary tank runs dry.=C2=A0 So you probably would not have the engin= e stumble then.=C2=A0 But to be able to transfer fuel by selecting another = tank, the air would need to be purged from the transfer pump to get it work= ing again.=C2=A0 This could be done by shutting the normally running injection pump off until the rail pressure dropped en= ough that the air in the transfer pump could be purged through the injector= s.=C2=A0 This might require more than just a stumble.=C2=A0 The engine woul= d need to be turning (probably windmilling at cruise speeds) so the fuel injectors would be active.

My fuel system has onl= y the two wing tanks.=C2=A0 It initially used a low pressure Facet pump to = transfer fuel.=C2=A0 I didn't like the low flow rate of that pump.=C2= =A0 So I replaced it with a third high pressure injection pump.=C2=A0 That = worked well but the possibility of developing more than 40 psi in the wing tank i= n case of a vent malfunction bothered me.=C2=A0 The tank would most likely = fail at pressures much less than this.=C2=A0 So I ended up with a duplex va= lve and returning fuel to the selected tank. =C2=A0A homemade duplex valve was used for several years while I saved up = the $ for the Andair valve.=C2=A0 This was a solution for me since I just h= ad the two tanks to deal with.

I still have the extra= injection pump and will set up a transfer system like you propose on my te= st stand just out of curiosity since what makes sense to me may not be how = the actual system behaves.

Steve Boese

On Mar 20, 2017, at 10:12 PM, Todd Bartrim <flyrotary@lancaironline.net> wr= ote:

If I was going to go with the transfer fuel plan I would jus= t have a separate inlet port into the main tank. That would eliminate any c= hance of air getting into the system.
=C2=A0 I once had a very complicated fuel system as I have 6 tanks (inboard= main, outboard auxiliary, wingtip aux-auxiliary) and I figured going to a = common header tank would simplify things. But it was prone to vapour lock. = But I had a solution for that which created another issue, which i had another solution for, etc. Things got very comp= lex.
Even when it was perfect on the ground I had several engine outs when in fl= ight during my test period due to vapor lock or air.
Managing 6 tanks is always going to be more complex, but I simplified it a = lot by going to a return-less system (deadheaded) like you are proposing. I= t worked well and eliminated all issues.
During my current rebuild I modified this again, but mostly just to clean i= t up as when I first modified it I was at the airport where I didn't ha= ve the shop resources that I have now.
=C2=A0 Most modern vehicles now use a returnless system for emissions requi= rements so this is nothing new, so I think your plan to deliver fuel from t= he main tank is simple and reliable. I would just change the transfer line.= Even if it seems like more work, it will be worth it because if you don't do it now while you are at home = in your shop, then if later you find out you need to do it after you are at= the airport you will be cussing. Unless you are one of those lucky SOBs th= at have a fully equipped private hangar! But still it is easier to do it while building.
=C2=A0 If you are determined to try it with the transfer plumbed into the d= elivery line, then at least install an inlet port with a cap in the main ta= nk so that it will be easy to change later. This is probably the best cours= e of action, as then you get to experiment which is what we're doing here, but have an easy fallback to planB.

On Mon, Mar 20, 2017, 11:06 PM Charlie England <flyrotary@lancair= online.net> wrote:
Hi Andrew,

I get you on the 'complicated system' issue. That's one reason = I'm considering this idea. And if I had any way to set up a gravity fed= sump for the aux tanks, I'd eliminate the aux tank selector valve. :-)=

Yeah, pumping air is the big vulnerability. If I go down this path, I'l= l definitely include a GEM optical sensor ahead of the transfer pump(s). I&= #39;ll also do some 'pumping air' testing. One in-tank injection pu= mp will be running during any transfer operation, so testing will determine whether air from the xfer pump will cause engine= stoppage, or just a stumble.

Thank you for the input. Anybody else? I'm not married to this, but I a= m giving it serious consideration.


Charlie


On 3/20/2017 8:51 PM, Andrew Martin wrote:
Charlie, I think that would = work. probably better to re-route the lines though, so fuel from Aux tanks = naturally wants to go through the regulator rather than to the fuel rail. e= ventually you will leave a transfer pump on and suck air.
In effect you've got 4 efi pumps, maybe just a little bit extreme, espe= cially if someone turns them all on.

Andrew
(currently repla= cing entire fuel system from tanks to rail. previous just too complex and h= eavy. sump tank, 2 pumps & 4 valves are coming out)

On Tue, Mar 21, = 2017 at 5:26 AM, Charlie England <flyrotary@lancaironline.net> wrote:
1st, let me define my delive= ry architecture. I like Tracy's idea of feeding the engine from one tan= k, and transferring aux tanks to the main tank. I understand the downside o= f being unable to switch tanks, but many a/c (including turbines) supply from one tank, so that's my choice. It avoids the need for a du= plex fuel selector, which I like. Effectively, I have 3 'aux' tanks= , and I'm using the stock (3 inlet) Van's RV fuel selector to feed = redundant transfer pumps in parallel.=C2=A0

I know that most have a sepa= rate return port in their tank(s) for regulator return. With my need for au= x transfer, my original plan was to 'T' the aux transfer line into = the regulator return line, which I'm pretty sure has been done before.<= /div>

I'm currently working on= installing both injection pumps in the fuel tank, conceptually similar to = standard auto practice for the last couple of decades: no risk of vapor loc= k with the added bonus of a very clean installation. The regulator will be in the wingroot, just outside the tank, with the manifold pressure= line running to that location for pressure control. (Deadheading fuel to t= he fuel rail has been done on both cars and a/c successfully; I believe it&= #39;s an option on the new SDS system being marketed to Lyc drivers now.)

The recent thread on fuel pr= essure changes while running both injection pumps got me thinking. If it= 9;s typical to see only a couple of PSI change when running both pumps, has= anyone considered running the transfer line into the regulator? The reason I'm considering this is twofold. It provides a 'final o= ption' for short term fuel delivery if both injection pumps are lost, a= nd, because the regulator is in the wingroot, I would need to run only one = fuel line to the supply tank.

I'll be using gerotor st= yle transfer pumps (positive displacement) and the aux selector has an '= ;off' position, so backflow won't be an issue.

A quick & dirty sketch i= s attached, diagramming the idea.

There would never be more th= an 2 pumps running at any time, since transfers would only happen in cruise= flight. Can anyone poke holes in this arrangement?=C2=A0

Charlie

--
Homepage:=C2=A0 http://www.flyrotary.com/
Archive and UnSub:=C2=A0 =C2=A0http://mail.lancaironline.net:81/lists/= flyrotary/List.html




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