X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=BpPjPrf5 c=1 sm=1 tr=0 a=vwdcpL8KuDK7wHPZlXiaPQ==:117 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=x7bEGLp0ZPQA:10 a=A-0mRrAPPO4A:10 a=Jdjhy38mL1oA:10 a=HZJGGiqLAAAA:8 a=Ia-xEzejAAAA:8 a=on22okXAAAAA:8 a=pGLkceISAAAA:8 a=7g1VtSJxAAAA:8 a=_V-tYiEmt5v1fADW5SoA:9 a=jrbin0MGXKIeIhoU:21 a=l42DUKdpp6sPAa74:21 a=QEXdDO2ut3YA:10 a=Py9Ta2HYjrcA:10 a=NALRNPPH8BMA:10 a=Qa1je4BO31QA:10 a=gvSQh4r-fQ0A:10 a=a0CRiA4mEkwK8xeT-KoA:9 a=NzDPdME0o1ikyl7j:21 a=nM5AYg1xB73hpj_p:21 a=_tD9IOxSh3ANEBiL:21 a=Urk15JJjZg1Xo0ryW_k8:22 a=NPqpj5bUEVj9vR1HIonK:22 a=grOzbf7U_OpcSX4AJOnl:22 From: "Charlie England ceengland7@gmail.com" Received: from mail-io1-f44.google.com ([209.85.166.44] verified) by logan.com (CommuniGate Pro SMTP 6.2.14) with ESMTPS id 13408112 for flyrotary@lancaironline.net; Mon, 20 Jan 2020 18:02:15 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.166.44; envelope-from=ceengland7@gmail.com Received: by mail-io1-f44.google.com with SMTP id c16so784135ioh.6 for ; Mon, 20 Jan 2020 15:02:16 -0800 (PST) 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=e2mUhlH55HLUuf3IxL6bdm+IId0K1FYDdH1vozBWNdQ=; b=DQ/2cH2Tf4t5S983lZctlpDpDBl6vGwsgMuWrJCKynrEwdyhYGKWoLs5tsWAd4HB1f uyAizyIAr6tjvPmWOR3Vy2eXAulybUvluxCRj5qOV8ZH6/Ltw7m1P3Hltf56v8+Ymvbp QvuR4u1eoN8Wa0158aMpzHfrgkSS0YUDSXLswBsVrzFWA+rEQAALAMBvqbQHtlymvRo8 hrc+i9+qMMrmJ/iEJk1HcIzLVWhAeJFpl4orXTA6N3gvuHqSVTCT2vGWCN/dk/iD9dXU /A1OSeDGc8LQRannLGBOLAf64kmyiUeztYP7mjukzFTbeMKx3ifJQO5cFHdVVXiSoYI9 CJiw== 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=e2mUhlH55HLUuf3IxL6bdm+IId0K1FYDdH1vozBWNdQ=; b=n8N21/b4col2dzAaMYmu92kGdwPYDmHuj9BYXIVVWCUkoWiolMya7NZF/o7jbH66C6 0ob3uJ7iMYkHwu6wj0JttRyxZR0FKrZkwz806usLcSlk/J9VfM7I3kVt5VjSyFC20j0X UUQ4cjls7dbFRb/O2T7lU1JlSgc4+sJBm5GwIpUTV2nwk34wI1zsq4vTCFiDTaJNtVNw JjGgz0twJk38qLBgf6TpcX3gWo2FgxuGaCq50YYaacV9Ze8oR50AYzUuxqexc4Dz4XCi w4Iq7iWpy96qb0JT5o5tTCVIkALCUS1+l/URYA6OtJ3DoSvFmzjLAbjf3BpJkgco60ew O7Pw== X-Gm-Message-State: APjAAAVGlFc+n+yipgr9hZyNxZ6r00tqNrdzPkIi/k7aIUGaFDRH0yvA cjKYRmbGz8ZW98XxT7XsmctEqcWMwNN1nSkfSHEmaQ== X-Google-Smtp-Source: APXvYqzb1xU4nsOyYJdwbynphrJRtG229fL51kuRFOk86R7qhjJzGThi0zBG8hYx2Q1pxoJ9ns5eXvKMqY0AzsOvu2M= X-Received: by 2002:a6b:6e02:: with SMTP id d2mr1005544ioh.22.1579561318709; Mon, 20 Jan 2020 15:01:58 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Mon, 20 Jan 2020 16:59:16 -0600 Message-ID: Subject: Re: [FlyRotary] Re: Fuel System Design for High wing Aircraft To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="0000000000004d7e97059c9a47e3" --0000000000004d7e97059c9a47e3 Content-Type: text/plain; charset="UTF-8" It's obviously do-able, but there are several issues that make what you're proposing....complicated. It just can't be done truly returnless with gerotor or roller vane pumps. They pump far more fuel than the engine (variably) needs, and because they are positive displacement pumps, they will either stall or break something else in the fuel system due to excess pressure. You can make the system 'dead head' at the injectors, but there must be some form of bypass regulator somewhere between pump output and injectors. Bypassing excess flow back to the input of the pump will *sometimes* work, but it's too unpredictable for most to trust it in an a/c. If the system ever sucks air for any reason (or vaporized fuel after shutdown manages to push back through the pump to the inlet), the pump will airlock and just recirculate air because air is easier to move than fuel. Add to that the fact that pressure invariably varies with flow, and if pressure varies at the injector, injector flow varies with the same open time, which will make tuning an...adventure. Cars are returnless by using some variation of the technique shown in the product that Steve linked earlier, combined with in-tank *turbine style* pumps. So, intank turbine pump, pressure controlled by a MAP sensing controller, and you're done. Except, now you need another intank pump and controller for reduncancy. Two tanks? Two more pumps and two more controllers, plus switching. Or a switching array that would make a single pump look reliable and safe. A high wing a/c with a sump (header) tank would make life simpler, since only one pair of injection pumps would be needed in the sump tank. Charlie On Mon, Jan 20, 2020 at 4:33 PM Ernest Christley echristley@att.net < flyrotary@lancaironline.net> wrote: > Does the fuel necessarily have to be returned? What is the benefit of > returning it? Injectors can take 50lbs of pressure. In fact, they make a > better spray with the higher pressure, and atomize even better if the fuel > is sprayed hot. Many modern cars don't have a return. As long as you keep > the pumps and the gas going to them cool, you won't get vapor lock. > > Keep the fuel pump below the injectors and behind the firewall. It'll > draw cool fuel and then pressurize it to keep it liquid until it is > sprayed. On shutdown, the fuel in the line firewall forward will get hot > and vaporize, pushing liquid back to the pump. But, as soon as the pump is > flipped on the vapor gets compressed and liquified again for the rest of > its time in the line. > > I could be wrong. . . > > On Monday, January 20, 2020, 10:43:07 AM EST, Jeff Whaley > jwhaley@datacast.com wrote: > > > Hi Bobby, yes Ed used a small (1 qt) can attached to the engine-side of > the firewall, to accept main fuel IN, return fuel and parallel outputs to > his fuel pumps. This system would work regardless of wing arrangement but > I'm not too sure how it performed at keeping LOW fuel temperatures. > > My high-wing has a 2 gallon header tank on the cabin-side of the firewall, > so I Tee'd my fuel return into one of its two vent lines that connect back > to the wing tanks. This is a gravity-fed system until it passes through > the firewall to the pumps ... the vent lines assist in draining the tanks > evenly. > Jeff > > What is the best method for handling return fuel in a high wing? Fuel > return to a small header tank sized to keep fuel temperatures low? I think > Ed Anderson may have used a small header in his RV6. > > Asking for a friend with an airplane addiction. > > Bobby > > -----Original Message----- > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] > Sent: January-20-20 6:01 AM > To: Rotary motors in aircraft > Subject: flyrotary Digest #4865 > > Rotary motors in aircraft Digest #4865 > > 1) Re: Mufflers > by "Neil Unger 12348ung@gmail.com" > 2) Re: Mufflers > by "Charlie England ceengland7@gmail.com" > > > This digest is sent to you because you are subscribed to > the mailing list . > To unsubscribe, E-mail to: To switch to > the FEED mode, E-mail to > Send administrative queries to > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > --0000000000004d7e97059c9a47e3 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
It's obviously do-able, but there are several issues that= make what you're proposing....complicated. It just can't be done t= ruly returnless with gerotor or roller vane pumps. They pump far more fuel = than the engine (variably) needs, and because they are positive displacemen= t pumps, they will either stall or break something else in the fuel system = due to excess pressure. You can make the system 'dead head' at the = injectors, but there must be some form of bypass regulator somewhere betwee= n pump output and injectors. Bypassing excess flow back to the input of the= pump will *sometimes* work, but it's too unpredictable for most to tru= st it in an a/c. If the system ever sucks air for any reason (or vaporized = fuel after shutdown manages to push back through the pump to the inlet), th= e pump will airlock and just recirculate air because air is easier to move = than fuel. Add to that the fact that pressure invariably varies with flow, = and if pressure varies at the injector, injector flow varies with the same = open time, which will make tuning an...adventure.

Cars are returnless by using some variation of the= technique shown in the product that Steve linked earlier, combined with in= -tank *turbine style* pumps. So, intank turbine pump, pressure controlled b= y a MAP sensing controller, and you're done. Except, now you need anoth= er intank pump and controller for reduncancy. Two tanks? Two more pumps and= two more controllers, plus switching. Or a switching array that would make= a single pump look reliable and safe.

A high wing a/c with a sump (header) tank would make life sim= pler, since only one pair of injection pumps would be needed in the sump ta= nk.

<= div class=3D"gmail_default" style=3D"font-size:small">Charlie
On Mon, = Jan 20, 2020 at 4:33 PM Ernest Christley echristley@att.net <flyrotary@lancaironline.net> wrote:
Does the fuel necessarily have to be returned?=C2= =A0 What is the benefit of returning it?=C2=A0 Injectors can take 50lbs of = pressure.=C2=A0 In fact, they make a better spray with the higher pressure,= and atomize even better if the fuel is sprayed hot.=C2=A0 Many modern cars= don't have a return.=C2=A0 As long as you keep the pumps=C2=A0 and the= gas going to them cool, you won't get vapor lock.=C2=A0

Keep the fuel pump below the inject= ors and behind the firewall.=C2=A0 It'll draw cool fuel and then pressu= rize it to keep it liquid until it is sprayed.=C2=A0 On shutdown, the fuel = in the line firewall forward will get hot and vaporize, pushing liquid back= to the pump.=C2=A0 But, as soon as the pump is flipped on the vapor gets c= ompressed and liquified again for the rest of its time in the line.

I could be wrong. . .
<= div>
=20
=20
On Monday, January 20, 2020, 10:43:07 AM EST, Jeff Whal= ey jwhaley@dataca= st.com <flyrotary@lancaironline.net> wrote:


Hi Bobby, yes Ed used a small (1 qt) = can attached to the engine-side of the firewall, to accept main fuel IN, re= turn fuel and parallel outputs to his fuel pumps.=C2=A0 This system would w= ork regardless of wing arrangement but I'm not too sure how it performe= d at keeping LOW fuel temperatures.

My high-wing has a 2 gallon header tank on the cabin-side of = the firewall, so I Tee'd my fuel return into one of its two vent lines = that connect back to the wing tanks.=C2=A0 This is a gravity-fed system unt= il it passes through the firewall to the pumps ... the vent lines assist in= draining the tanks evenly.
Jeff

What is the best method for handling= return fuel in a high wing? Fuel return to a small header tank sized to ke= ep fuel temperatures low? I think Ed Anderson may have used a small header = in his RV6.

Asking for= a friend with an airplane addiction.

<= div dir=3D"ltr">Bobby

= -----Original Message-----
From: Rotary motors in= aircraft [mailto:flyrotary@lancaironline.net]
Sent: J= anuary-20-20 6:01 AM
To: Rotary motors in aircraf= t
Subject: flyrotary Digest #4865

=C2=A0 =C2=A0 =C2=A0 =C2=A0 Rotary mo= tors in aircraft Digest #4865

1) Re: Mufflers
=C2=A0 =C2=A0 by "= Neil Unger 12348ung= @gmail.com" <flyrotary@lancaironline.net>
2) Re: Mufflers
=C2=A0 =C2=A0 by "Charlie= England ceenglan= d7@gmail.com" <flyrotary@lancaironline.net>

This digest is sent to you because you are s= ubscribed to
=C2=A0 the mailing list <flyrotary@lancair= online.net>.
To unsubscribe, E-mail to: &l= t;flyr= otary-off@lancaironline.net> To switch to the FEED mode, E-mail to &= lt;fl= yrotary-feed@lancaironline.net>
Send admin= istrative queries to=C2=A0 <flyrotary-request@lancaironline.net>


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