X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-pg0-f42.google.com ([74.125.83.42] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9596041 for flyrotary@lancaironline.net; Wed, 22 Mar 2017 08:35:42 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.83.42; envelope-from=ceengland7@gmail.com Received: by mail-pg0-f42.google.com with SMTP id w20so5550532pgc.0 for ; Wed, 22 Mar 2017 05:35:42 -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=WpMZnMJsxdPLg5bCNlaQ/Zl+E/xJqr3Kg80eLulRkL0=; b=vKF+hnLJKQZeRKevLnTply4dNuEwhx/UeF9nui5VgzPWdQAqxGbnzsAKXAJC3vQ50e 8fPNF7esTV60MRD+BoRKftszG35B5F+lyEWilIpcVNdeZxkbT7SIWWdm809pBhn+ucVT /9WOuejJG5YpJ7/By2NbPaKRpk8R38Tc1pZGWsK4KSwSlZPLFdmnhS4SBdwHz9QE1Evo Qkk6/0Q7b46vI8+YH7q2Ff9RLik5jeTnFe4H+EeSTUVMLxaTazab6d01SnW4N5gO2fA9 LWSJbA8COL0BEMxgAZEGhnV3FnX16UY6NpDmqqBStNr0bxSMmJfwEaAv3rUXiaXx6NEh pw3g== 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=WpMZnMJsxdPLg5bCNlaQ/Zl+E/xJqr3Kg80eLulRkL0=; b=LtXzLMtxaxU/wH8Xt77bCdV9/Bvc4r9i838k5d3z6M8FI3Zt7REy312khZP4705d42 MNBNERD2J8sTuDVnWWROzhGfM4snnSi8QP+4Kd6AVsAfQD4BM4ZogbqFQDkzB2qj4XgE NJsi4SdIE3ZP2zyD9KoddVpU+IzBbMjHEKqQ6ZRRGnn/HPa3IVDnEs2f+rOjRXqnUwkK 7CJOvK0jQ27P50n4aDmqzOILrq8ghjX8Jxylj+uUYb3BSRMp5Fui3Bq3Fl99XHpP4u0a WxBMa8PsqTpJWA3q5iaEkL/EBxa/OmuMjLYCiRhibB3FJnCY3x0yeG9YPaSfsApaZyNF IoWg== X-Gm-Message-State: AFeK/H2/br9m/kGTZcrsrt3TqQdhmyzh04417+KIUA0crGo+opaBhgMGbRlFZA5iTBQVRFLur96KnJFI+pkuWg== X-Received: by 10.98.13.16 with SMTP id v16mr45852770pfi.38.1490186124992; Wed, 22 Mar 2017 05:35:24 -0700 (PDT) MIME-Version: 1.0 Received: by 10.100.128.83 with HTTP; Wed, 22 Mar 2017 05:35:24 -0700 (PDT) In-Reply-To: References: Date: Wed, 22 Mar 2017 07:35:24 -0500 Message-ID: Subject: Re: [FlyRotary] Re: fuel system peer review To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=001a11467c72a126aa054b50fe55 --001a11467c72a126aa054b50fe55 Content-Type: text/plain; charset=UTF-8 That is very interesting! I'd have thought there would at least be some stumbling while the xfer pump was pumping air, or running very rich while rail pressure was 8psi above normal. In your test setup, was the regulator at the fuel rail ('looped' from rail back to tank), or near the supply tank, with a 'dead head' run to the fuel rail? Many thanks for running the test; I'd almost decided to go back to 'conventional' plumbing. Now I'm back in analysis paralysis... BTW, are you flying the Renesis yet? Charlie On Tue, Mar 21, 2017 at 5:56 PM, Steven W. Boese < flyrotary@lancaironline.net> wrote: > Charlie, > > > I forgot to mention that the engine never missed a beat the entire time > that the transfer pump test was made. > > > Steve > ------------------------------ > *From:* Rotary motors in aircraft on behalf > of Steven W. Boese > *Sent:* Tuesday, March 21, 2017 4:52:53 PM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: fuel system peer review > > > Charlie, > > > I installed a system similar to your proposed diagram on my test stand > today. I used one gerotor fuel injection pump taking fuel from a separate > source and tee'd it into the line between the fuel pressure regulator and > the dead-ended fuel rail. When this pump was turned on, the fuel pressure > in the rail increased by about 8 psi (that setup uses 5/16 OD steel tubing > so the pressure increase with -6 tubing would most likely be less). When > the inlet to that transfer pump was unported, the fuel pressure returned to > normal at which time I turned the transfer pump off. With the transfer > pump turned off, there was a dribble of fuel coming out of the that pump's > inlet. Apparently, that pump does not completely stop the reverse flow of > fuel through it when there is pressure in the fuel rail. As a result, when > the inlet to the transfer pump was placed back below the level in the > auxiliary source and the pump was turned back on, it immediately began > pumping fuel into the pressurized line. Any air drawn into the pump had > been purged back out the pump's inlet. > > > If your transfer pump has the same imperfect check valve action, your > proposed system appears to work fine in spite of my air lock reservations. > Your selector valve with the "off" position would prevent long term reverse > flow of fuel through the transfer pump when it is shut off. > > > FWIW > > > Steve Boese > ------------------------------ > *From:* Rotary motors in aircraft on behalf > of Charlie England > *Sent:* Tuesday, March 21, 2017 2:55:54 PM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: fuel system peer review > > I did consider it, but that would mean 3 xfer pumps instead of 1+backup. > I'd still need a pair of injection pumps. In the same vein, I considered > the little turbine style in-tank pumps for that purpose, but then I'd need > a positive shutoff valve for the aux tanks. I also considered them for > injection pumps (lighter, smaller, lower power consumption) but they're > actually harder to mount with any configuration flexibility and I'd again > need a separate positive cutoff (gerotor pumps are positive cutoff when not > running). > > Thanks, > > Charlie > > On 3/21/2017 10:33 AM, Ernest Christley wrote: > > At the point you're at, what would be the downside to simply putting a > pump in each tank, and using a rotary switch to select? Having the main > tank with the return wired in with the ignition, so that it is always > running to avoid the return overfilling the tank. > > On Mar 20, 2017 5:26 PM, Charlie England > 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 > > > --001a11467c72a126aa054b50fe55 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
That is very interesting! I'd have thought there would= at least be some stumbling while the xfer pump was pumping air, or running= very rich while rail pressure was 8psi above normal.=C2=A0

<= div>In your test setup, was the regulator at the fuel rail ('looped'= ; from rail back to tank), or near the supply tank, with a 'dead head&#= 39; run to the fuel rail?=C2=A0

Many thanks for ru= nning the test; I'd almost decided to go back to 'conventional'= plumbing. Now I'm back in analysis paralysis...

BTW, are you flying the Renesis yet?

Ch= arlie

On Tue, = Mar 21, 2017 at 5:56 PM, Steven W. Boese <flyrotary@lancaironlin= e.net> wrote:

Charlie,


I forgot to mention that the engine never missed a beat the entire time = that the transfer pump test was made.


Steve

From: Rotary motors in aircraft <flyrotary@lancaironline.net<= /a>> on behalf of Steven W. Boese <flyrotary@lancaironline.net>
Sent: Tuesday, March 21, 2017 4:52:53 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: fuel system peer review
=C2=A0

Charlie,


I installed a system similar to your proposed diagram on my test stand t= oday.=C2=A0 I used one gerotor fuel injection pump taking fuel=C2=A0from a = separate source and tee'd it into the line between the fuel pressure re= gulator and the dead-ended fuel rail.=C2=A0 When this pump was turned on, the fuel pressure in the rail increased by about 8 psi= (that setup uses 5/16 OD steel tubing so the pressure increase with -6 tub= ing would most likely be less).=C2=A0 When the inlet to that transfer pump = was unported, the fuel pressure returned to normal at which time I turned the transfer pump off.=C2=A0 With the tra= nsfer pump turned off, there was a dribble of fuel coming out of the that p= ump's inlet.=C2=A0 Apparently, that pump does not completely stop the r= everse flow of fuel through it when there is pressure in the fuel rail.=C2=A0 As a result, when the inlet to the transfer pump w= as placed back below the level in the auxiliary source and the pump was tur= ned back on,=C2=A0it immediately began pumping fuel into the pressurized li= ne.=C2=A0=C2=A0Any air drawn into the pump had been purged=C2=A0back out the pump's inlet.


If your transfer pump has the same imperfect check valve action, your pr= oposed system appears to work fine in spite of my air lock reservations.=C2= =A0 Your selector valve with the "off" position would=C2=A0preven= t long term reverse flow of fuel through the transfer pump when it is shut off.=C2=A0=C2=A0


FWIW


Steve Boese=C2=A0=C2=A0

From: Rotary motors in aircraft <flyrotary@lancaironline.net<= /a>> on behalf of Charlie England <flyrotary@lancaironline.net>
Sent: Tuesday, March 21, 2017 2:55:54 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: fuel system peer review
=C2=A0
I did consider it, but that would mean 3 xfer pumps instead of 1+backup= . I'd still need a pair of injection pumps. In the same vein, I conside= red the little turbine style in-tank pumps for that purpose, but then I'= ;d need a positive shutoff valve for the aux tanks. I also considered them for injection pump= s (lighter, smaller, lower power consumption) but they're actually hard= er to mount with any configuration flexibility and I'd again need a sep= arate positive cutoff (gerotor pumps are positive cutoff when not running).

Thanks,

Charlie

On 3/21/2017 10:33 AM, Ernest Christley wrote:
At the point you're at, what would be the downside to= simply putting a pump in each tank, and using a rotary switch to select?= =C2=A0 Having the main tank with the return wired in with the ignition, so = that it is always running to avoid the return overfilling the tank.

On Mar 20, 2017 5:26 PM, Charlie England <flyrotary@lancaironline.net> wrote:
1st, let me define my delivery architecture. I like Tracy's idea o= f 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 se= lector, 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 tr= ansfer pumps in parallel.=C2=A0

I know that most have a separate return port in their tank(s) for regu= lator 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 p= retty sure has been done before.

I'm currently working on installing both injection pumps in the fu= el 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 ins= tallation. The regulator will be in the wingroot, just outside the tank, with the manifold pressure line runni= ng to that location for pressure control. (Deadheading fuel to the fuel rai= l has been done on both cars and a/c successfully; I believe it's an op= tion on the new SDS system being marketed to Lyc drivers now.)

The recent thread on fuel pressure changes while running both injectio= n pumps got me thinking. If it's typical to see only a couple of PSI ch= ange when running both pumps, has anyone considered running the transfer li= ne into the regulator? The reason I'm considering this is twofold. It provides a 'final option' for shor= t term fuel delivery if both injection pumps are lost, and, because the reg= ulator is in the wingroot, I would need to run only one fuel line to the su= pply 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 tran= sfers would only happen in cruise flight. Can anyone poke holes in this arr= angement?=C2=A0

Charlie

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


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