X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-da05.mx.aol.com ([205.188.105.147] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4165893 for flyrotary@lancaironline.net; Sun, 14 Mar 2010 23:29:52 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.147; envelope-from=SHIPCHIEF@aol.com Received: from imo-da01.mx.aol.com (imo-da01.mx.aol.com [205.188.169.199]) by imr-da05.mx.aol.com (8.14.1/8.14.1) with ESMTP id o2F3TAMK011142 for ; Sun, 14 Mar 2010 23:29:10 -0400 Received: from SHIPCHIEF@aol.com by imo-da01.mx.aol.com (mail_out_v42.9.) id q.cef.72fca0cf (43970) for ; Sun, 14 Mar 2010 23:29:06 -0400 (EDT) Received: from smtprly-dc01.mx.aol.com (smtprly-dc01.mx.aol.com [205.188.170.1]) by cia-dd03.mx.aol.com (v127_r1.2) with ESMTP id MAILCIADD033-d1c14b9da97e33b; Sun, 14 Mar 2010 23:29:05 -0500 Received: from webmail-m092 (webmail-m092.sim.aol.com [64.12.102.42]) by smtprly-dc01.mx.aol.com (v127.7) with ESMTP id MAILSMTPRLYDC012-d1c14b9da97e33b; Sun, 14 Mar 2010 23:29:02 -0500 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: fuel supply problem? Date: Sun, 14 Mar 2010 23:29:02 -0400 X-AOL-IP: 24.19.204.151 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: shipchief@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CC9206CAD38E4B_2BD0_1A1B5_webmail-m092.sysops.aol.com" X-Mailer: AOL Webmail 30746-STANDARD Received: from 24.19.204.151 by webmail-m092.sysops.aol.com (64.12.102.42) with HTTP (WebMailUI); Sun, 14 Mar 2010 23:29:02 -0400 Message-Id: <8CC9206CACC690E-2BD0-CCB4@webmail-m092.sysops.aol.com> X-Spam-Flag:NO X-AOL-SENDER: SHIPCHIEF@aol.com ----------MB_8CC9206CAD38E4B_2BD0_1A1B5_webmail-m092.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The fuel return location in the tank worries me. I have an RV-8, and I ins= talled a finger strainer at the most aft corner of each tank, threaded int= o a special thick rib insert. The fuel return is through the original Van'= s pick-up location, with the bulkhead fitting squirting the return fuel= straight down. I worry that when the tank gets low, return fuel might en= train air in the pick-up fuel? I had considered a vapor recovery container= like a sphere with a vapor line off the top, which takes fuel out of the= center for limited inverted flight. Which won't work for that purpose on= the discharge side of the fuel pump. (pressure would still be lost and en= gine would quit. But air bubbles in fuel would separate and vent back to= the tank well enough. Anyway, I'm not doing it because it adds weight and= complexity, and I don't know if I even need such a thing. yet. -----Original Message----- From: Bill Schertz To: Rotary motors in aircraft Sent: Sun, Mar 14, 2010 7:25 pm Subject: [FlyRotary] Re: fuel supply problem? Mike, When you are down to 5 gallons, remember that you are returning fuel to th= e tank, therefore could it be 'foaming' as it is transferred back, causing= the pump to pick up some vapor/air ? Where does that returned fuel enter= the tank, at the root or up the tank aways. If up the tank, it takes a li= ttle time to flow back down to the inlet. =20 Something to consider. Bill Schertz KIS Cruiser #4045 N343BS Phase I testing From: Mike Wills=20 Sent: Saturday, March 13, 2010 10:29 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: fuel supply problem? I'm pretty sure the turn was coordinated. Knowing that both tanks were app= roaching (if not below) 5 gallons, it was the first thing I thought of and= I looked at the ball. It was centered. And I'm sure there is going to tur= n out to be about 5 gallons left in the tank so its hard to understand how= this could have been an issue with the pickup uncovering. I just don=E2= =80=99t have a better explanation. If the pump failed I would expect it to= stay failed, not work fine on the ground. =20 I didn=E2=80=99t copy it, but my system I believe is the same that Ian Bea= dle used. I have 1 pump for each tank. The outputs are T'eed together - ch= eck valves built into the pumps prevents crossfeed. Both tanks have return= lines. The return line from the fuel rail goes through an industrial grad= e electric valve. =20 I chose this design for a couple of reasons: 1) Operational simplicity. I reasoned that most fuel related problems in= flight are due to stupid pilot tricks so wanted a system that was as simp= le to operate as possible. In its original configuration all that was requ= ired to switch tanks was to flip a single toggle switch on the panel which= would energize the appropriate pump and configure the return valve to ret= urn fuel to the tank it came from. This has since been modified slightly= to have individual switches for each pump so both can be on at the same= time if needed. 2) I had previous experience (bad) with EFI in some project cars before I= built the airplane. I had a couple of fuel pump failures and in researchi= ng found strong recommendations against putting the fuel pump too far from= the fuel tank. These pumps are designed to push fuel, not draw fuel. A de= sign where both pumps have access to both tanks requires the pumps to be= downstream of the fuel selector with several feet of fuel line ahead of= the pump. I wanted to avoid this type of design although it apparently is= working fine for Ed. My pumps are just inboard of the wing roots literall= y a couple of inches from the pickups in the tanks. =20 Tracy's system is mechanically simple but has the potential for pilot erro= r resulting in pumping fuel overboard if the transfer pump is forgotten an= d left on. Yes, I know there are ways to address that. And clearly it work= s for him. =20 I think (thought?) I pretty well understand the pros and cons in my setup.= All things being equal I think before yesterday's incident I would do it= this way again. If it turns out that the issue was due to uncovering the= pickup (not real sure how to prove that) I'd consider changing to include= a header tank with a deep sump to prevent re-occurance. But I don=E2=80= =99t think I'd rely on suction to fill the header, think I'd use a low pre= ssure pump like the typical Facet pump. =20 One thing is for certain. Unlike a carbureted engine which has a little cu= shion due to fuel in a float bowl, the instant fuel pressure drops this en= gine quits. It's an attention getter. Particularly when you are at the opp= osite corner of your test box from your home base. I ended up flying back= about 70 miles hopscotching from field to field. =20 Mike=20 From: Ed Anderson=20 Sent: Saturday, March 13, 2010 1:53 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: fuel supply problem? There is certainly more than one way to design a reliable fuel system =E2= =80=93 each with its pros and cons. I too did not want a six way value fo= r switching fuel between two tanks and the engine with the ugh return line= . Besides I had already constructed my fuel system pretty much according= to Van=E2=80=99s instructions. So to preclude a return line I came up wi= th my =E2=80=9Calmost returnless=E2=80=9D system. It uses a =C2=BD pint= capacity small header tank to return the injector fuel =E2=80=93 the fuel= injected to the engine comes from this header tank thereby creating a =E2= =80=9Cvacuum=E2=80=9D in the tank which pulls fresh fuel from the wing tan= ks. It has worked fine for over 10 years. =20 Both fuel pumps draw from this header tank and either tank can feed it and= I have no return lines going back to the tanks. =20 But, Tracy=E2=80=99s approach has shown to work just fine =E2=80=93 not kn= ocking it by any means. =20 Ed =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Be= half Of Bktrub@aol.com Sent: Friday, March 12, 2010 11:43 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: fuel supply problem? =20 I just copied Tracy's setup- all fuel is pumped from the right tank, and= fuel is transferred from the left into the right by a Facet pump. I didn'= t want to get into having a six port fuel valve in order to get the fuel= injection to return to the tank I was using at the time. =20 It's really simple, and hopefully that means reliable. We'll have to see,= as this plane is looking for it's airworthiness inspection in the next fe= w months.=20 =20 Brian Trubee __________ Information from ESET NOD32 Antivirus, version of virus signatu= re database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ----------MB_8CC9206CAD38E4B_2BD0_1A1B5_webmail-m092.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" The fuel return location= in the tank worries me. I have an RV-8, and I installed a finger strainer= at the most aft corner of each tank, threaded into a special thick= rib insert. The fuel return is through the original Van's pick-up lo= cation, with the  bulkhead fitting squirting the return fuel straight= down. I worry that when the tank gets low, return fuel  might e= ntrain air in the pick-up fuel? I had considered a vapor recovery containe= r like a sphere with a vapor line off the top, which takes fuel out of the= center for limited inverted flight. Which won't work for that purpose on= the discharge side of the fuel pump. (pressure would still be lost and en= gine would quit. But air bubbles in fuel would separate and vent back to= the tank well enough. Anyway, I'm not doing it because it adds weight and= complexity, and I don't know if I even need such a thing. yet.



-----Original Message-----
From: Bill Schertz <wschertz@comcast.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sun, Mar 14, 2010 7:25 pm
Subject: [FlyRotary] Re: fuel supply problem?

Mike,
When you are down to 5 gallons, remember= that you are returning fuel to the tank, therefore could it be 'foaming'= as it is transferred back, causing the pump to pick up some vapor/air ?= Where does that returned fuel enter the tank, at the root or up the tank= aways. If up the tank, it takes a little time to flow back down to the in= let.
 
Something to consider.
Bill Schertz
KIS Cruiser #4045
N343BS
Phase I testing

From: Mike Wills
Sent: Saturday, March 13, 2010 10:29 AM
Subject: [FlyRotary] Re: fuel supply problem?

I'm pretty sure the turn was coordinated. K= nowing that both tanks were approaching (if not below) 5 gallons, it was= the first thing I thought of and I looked at the ball. It was centered.= And I'm sure there is going to turn out to be about 5 gallons left in the= tank so its hard to understand how this could have been an issue with the= pickup uncovering. I just don=E2=80=99t have a better explanation. If the= pump failed I would expect it to stay failed, not work fine on the ground= .
 
I didn=E2=80=99t copy it, but my system I believ= e is the same that Ian Beadle used. I have 1 pump for each tank. The outpu= ts are T'eed together - check valves built into the pumps prevents crossfe= ed. Both tanks have return lines. The return line from the fuel rail goes= through an industrial grade electric valve.
 
I chose this design for a couple of reasons:
1) Operational simplicity. I reasoned that= most fuel related problems in flight are due to stupid pilot tricks so wa= nted a system that was as simple to operate as possible. In its original= configuration all that was required to switch tanks was to flip a single= toggle switch on the panel which would energize the appropriate pump and= configure the return valve to return fuel to the tank it came from. This= has since been modified slightly to have individual switches for each pum= p so both can be on at the same time if needed.
2) I had previous experience (bad) with EFI in= some project cars before I built the airplane. I had a couple of fuel pum= p failures and in researching found strong recommendations against putting= the fuel pump too far from the fuel tank. These pumps are designed to pus= h fuel, not draw fuel. A design where both pumps have access to both tanks= requires the pumps to be downstream of the fuel selector with several fee= t of fuel line ahead of the pump. I wanted to avoid this type of design al= though it apparently is working fine for Ed. My pumps are just inboard of= the wing roots literally a couple of inches from the pickups in the tanks= .
 
Tracy's system is mechanically simple but has th= e potential for pilot error resulting in pumping fuel overboard if the tra= nsfer pump is forgotten and left on. Yes, I know there are ways to address= that. And clearly it works for him.
 
I think (thought?) I pretty well understand the= pros and cons in my setup. All things being equal I think before yes= terday's incident I would do it this way again. If it turns out that= the issue was due to uncovering the pickup (not real sure how to prove th= at) I'd consider changing to include a header tank with a deep sump to pre= vent re-occurance. But I don=E2=80=99t think I'd rely on suction to fill= the header, think I'd use a low pressure pump like the typical Facet pump= .
 
One thing is for certain. Unlike a carbureted en= gine which has a little cushion due to fuel in a float bowl, the instant= fuel pressure drops this engine quits. It's an attention getter. Particul= arly when you are at the opposite corner of your test box from your home= base. I ended up flying back about 70 miles hopscotching from field to fi= eld.
 
Mike 

Sent: Saturday, March 13, 2010 1:53 AM
Subject: [FlyRotary] Re: fuel supply problem?

There is certainly= more than one way to design a reliable fuel system =E2=80=93 each with it= s pros and cons.  I too did not want a six way value for switching fu= el between two tanks and the engine with the ugh return line.  Beside= s I had already constructed my fuel system pretty much according to Van=E2= =80=99s instructions.  So to preclude a return line I came up with my= =E2=80=9Calmost returnless=E2=80=9D system.  It uses a =C2=BD pint= capacity small header tank to return the injector fuel =E2=80=93 the fuel= injected to the engine comes from this header tank thereby creating a =E2= =80=9Cvacuum=E2=80=9D in the tank which pulls fresh fuel from the wing tan= ks.  It has worked fine for over 10 years.
 
Both fuel pumps dra= w from this header tank and either tank can feed it and I have no return= lines going back to the tanks.
 
But, Tracy=E2=80=99= s approach has shown to work just fine =E2=80=93 not knocking it by any me= ans.
 
Ed
 
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of B= ktrub@aol.com
Sent: Friday, March 12, 20= 10 11:43 PM
To: Rotary motors in aircr= aft
Subject: [FlyRotary] Re:= fuel supply problem?
 
I just copied Tra= cy's setup- all fuel is pumped from the right tank, and fuel is transferre= d from the left into the right by a Facet pump. I didn't want to get into= having a six port fuel valve in order to get the fuel injection to return= to the tank I was using at the time.  
It's really simpl= e, and hopefully that means reliable. We'll have to see, as this plane is= looking for it's airworthiness inspection in the next few months. =
 
Brian Trubee


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