X-Virus-Scanned: clean according to Sophos on Logan.com From: "Todd Bartrim" Received: from mail-qt0-f174.google.com ([209.85.216.174] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9591162 for flyrotary@lancaironline.net; Tue, 21 Mar 2017 00:12:18 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.216.174; envelope-from=bartrim@gmail.com Received: by mail-qt0-f174.google.com with SMTP id r45so122716696qte.3 for ; Mon, 20 Mar 2017 21:12:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=2eiTAyPcwz6kM8fBZUM35Lo6UAO7MFJfvKNwihhxc5g=; b=Vr18HCYegbBTe+z3erALykyYXwaSOnxKYKoM++SZ9sBbUWjKKMUXjHBYTOoS5gRVf8 r79RU17maIAOdz+L6lZhWLeuWKwhvjr5UiF/TPXH0cV9KCELIquhjpvmmUZdW0lhkikT YwcYnO9ramZYhSrLMAbIAZtFAlcNz5IQ7K4R4kAxkhXJp0kl6laoW3k4r116VwsXzkcV xb8NcNtv1FNgioo/hzt7MdJyZzf6UDrzqwTFpBBaGGrfil2ZhIXXNruY72XANC/iZm1W Hx5gM1ghCzn3qrqL7xpvXKOUo/O12w8ah+G5BVv26pFKyfOahnhWBNITZaymuEwgLql+ PD4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=2eiTAyPcwz6kM8fBZUM35Lo6UAO7MFJfvKNwihhxc5g=; b=kRq83qUHRTiY5LeHR5LPlyz66E0OW+LkTq3KJZvyR2NqzsKrYzkFxQyP/swrOJt3bm 4j3ocRza07tLwmFs34bkfIox9VmAQAPctYYG9rp6ZcSW/hyCPvGU4XHHBc1b0aUDgZC2 Kl96zQC4/5ZPt+8foJaVvt15Ow4+2Cm0v7UVIMlFTXK/NJqcBFIrNKF19oqfMV9wy8VA 9UJnLhDPIsN6vtoHn23axSiQ4/iYlrNWDZd3M2fmb2x3iTosVroj0Aqd97X5ML6Iebz4 WANnNeUZlokaYGOB8cCwKw0+81MJdPM1kjk8kPN+JZ5FOppbuwokHz+e5wGaltoe+1ZJ O8dQ== X-Gm-Message-State: AFeK/H3T6Uv8R084SRMVJHcAdj20Hh3TyyerfssutJzS0Dm0lpyvJtmN+ghvUqr+c8gOFYTgZe4ZnThdStxBLQ== X-Received: by 10.237.62.28 with SMTP id l28mr15883919qtf.89.1490069520038; Mon, 20 Mar 2017 21:12:00 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 21 Mar 2017 04:11:49 +0000 Message-ID: Subject: Re: [FlyRotary] Re: fuel system peer review To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=001a11441e1a6f2b82054b35d8d0 --001a11441e1a6f2b82054b35d8d0 Content-Type: text/plain; charset=UTF-8 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 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 > > > > --001a11441e1a6f2b82054b35d8d0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

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 anot= her solution for, etc. Things got very complex.
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= 9;t do it now while you are at home in your shop, then if later you find ou= t you need to do it after you are at the airport you will be cussing. Unles= s you are one of those lucky SOBs that 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 he= re, but have an easy fallback to planB.


On Mon, Mar 20, 2017, 11:06= PM Charlie England <flyr= otary@lancaironline.net> wrote:
=20 =20 =20
Hi Andre= w,

I get you on the 'complicated system' issue. That's one r= eason 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. probab= ly 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 entir= e 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 <<= a href=3D"mailto:flyrotary@lancaironline.net" class=3D"gmail_msg" target=3D= "_blank">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, an= d 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 separa= te 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 i= nstalling 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 pres= sure 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 sho= rt 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 styl= e transfer pumps (positive displacement) and the aux selector has an 'off' position, so backflow won't be a= n 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?=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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