From: "Andrew Martin" <flyrotary@lancaironline.net>
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Date: Tue, 21 Mar 2017 09:51:50 +0800
Message-ID: <CAJxaVD0MSBB1QWSfHxM_Optqw4tr=WfrQqnufsQ3mSCGcnH8sw@mail.gmail.com>
Subject: Re: [FlyRotary] fuel system peer review
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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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
>
>

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<div dir=3D"ltr"><div><div>Charlie, I think that would work. probably bette=
r to re-route the lines though, so fuel from Aux tanks naturally wants to g=
o through the regulator rather than to the fuel rail. eventually you will l=
eave a transfer pump on and suck air.<br></div>In effect you&#39;ve got 4 e=
fi pumps, maybe just a little bit extreme, especially if someone turns them=
 all on.<br><br></div>Andrew<br><div><div><div class=3D"gmail_extra">(curre=
ntly replacing entire fuel system from tanks to rail. previous just too com=
plex and heavy. sump tank, 2 pumps &amp; 4 valves are coming out) <br></div=
><div class=3D"gmail_extra">
<br><div class=3D"gmail_quote">On Tue, Mar 21, 2017 at 5:26 AM, Charlie Eng=
land <span dir=3D"ltr">&lt;<a href=3D"mailto:flyrotary@lancaironline.net" t=
arget=3D"_blank">flyrotary@lancaironline.net</a>&gt;</span> wrote:<br><bloc=
kquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #cc=
c solid;padding-left:1ex"><div dir=3D"ltr"><div>1st, let me define my deliv=
ery architecture. I like Tracy&#39;s idea of feeding the engine from one ta=
nk, 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 f=
rom one tank, so that&#39;s my choice. It avoids the need for a duplex fuel=
 selector, which I like. Effectively, I have 3 &#39;aux&#39; tanks, and I&#=
39;m using the stock (3 inlet) Van&#39;s RV fuel selector to feed redundant=
 transfer pumps in parallel.=C2=A0</div><div><br></div><div>I know that mos=
t have a separate return port in their tank(s) for regulator return. With m=
y need for aux transfer, my original plan was to &#39;T&#39; the aux transf=
er line into the regulator return line, which I&#39;m pretty sure has been =
done before.</div><div><br></div><div>I&#39;m currently working on installi=
ng 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 th=
e added bonus of a very clean installation. The regulator will be in the wi=
ngroot, just outside the tank, with the manifold pressure line running to t=
hat location for pressure control. (Deadheading fuel to the fuel rail has b=
een 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.)</div><div><br></div=
><div>The recent thread on fuel pressure changes while running both injecti=
on pumps got me thinking. If it&#39;s typical to see only a couple of PSI c=
hange when running both pumps, has anyone considered running the transfer l=
ine into the regulator? The reason I&#39;m considering this is twofold. It =
provides a &#39;final option&#39; for short term fuel delivery if both inje=
ction pumps are lost, and, because the regulator is in the wingroot, I woul=
d need to run only one fuel line to the supply tank.</div><div><br></div><d=
iv>I&#39;ll be using gerotor style transfer pumps (positive displacement) a=
nd the aux selector has an &#39;off&#39; position, so backflow won&#39;t be=
 an issue.</div><div><br></div><div>A quick &amp; dirty sketch is attached,=
 diagramming the idea.<br></div><div><br></div><div>There would never be mo=
re than 2 pumps running at any time, since transfers would only happen in c=
ruise flight. Can anyone poke holes in this arrangement?=C2=A0</div><span c=
lass=3D"HOEnZb"><font color=3D"#888888"><div><br></div><div>Charlie</div></=
font></span></div>
<br>--<br>
Homepage:=C2=A0 <a href=3D"http://www.flyrotary.com/" rel=3D"noreferrer" ta=
rget=3D"_blank">http://www.flyrotary.com/</a><br>
Archive and UnSub:=C2=A0 =C2=A0<a href=3D"http://mail.lancaironline.net:81/=
lists/flyrotary/List.html" rel=3D"noreferrer" target=3D"_blank">http://mail=
.lancaironline.net:<wbr>81/lists/flyrotary/List.html</a><br>
<br></blockquote></div><br></div></div></div></div>

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