X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from qmta13.emeryville.ca.mail.comcast.net ([76.96.27.243] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4165765 for flyrotary@lancaironline.net; Sun, 14 Mar 2010 22:26:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=76.96.27.243; envelope-from=wschertz@comcast.net Received: from omta07.emeryville.ca.mail.comcast.net ([76.96.30.59]) by qmta13.emeryville.ca.mail.comcast.net with comcast id tBpo1d0051GXsucADERheZ; Mon, 15 Mar 2010 02:25:41 +0000 Received: from WschertzPC ([71.57.77.95]) by omta07.emeryville.ca.mail.comcast.net with comcast id tERe1d00A23NHuF8TERgyH; Mon, 15 Mar 2010 02:25:40 +0000 Message-ID: <77D73F45A4DD4E25A1DCBE935FDBF56F@WschertzPC> From: "Bill Schertz" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: fuel supply problem? Date: Sun, 14 Mar 2010 21:25:37 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0040_01CAC3BC.E38850B0" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8089.726 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8089.726 This is a multi-part message in MIME format. ------=_NextPart_000_0040_01CAC3BC.E38850B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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 inlet. 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 = 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't have a better explanation. If the pump failed I would = expect it to stay failed, not work fine on the ground. I didn't copy it, but my system I believe is the same that Ian Beadle = used. I have 1 pump for each tank. The outputs are T'eed together - = check valves built into the pumps prevents crossfeed. 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 wanted 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 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 = researching 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 design 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 literally a couple of inches from the pickups in the = tanks. Tracy's system is mechanically simple but has the potential for pilot = error resulting in pumping fuel overboard if the transfer 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 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't 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 engine 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. Particularly 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 field. 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 - = each with its pros and cons. I too did not want a six way value for = 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's instructions. So to preclude a return line I came up = with my "almost returnless" system. It uses a =BD pint capacity small = header tank to return the injector fuel - the fuel injected to the = engine comes from this header tank thereby creating a "vacuum" in the = tank which pulls fresh fuel from the wing tanks. 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's approach has shown to work just fine - not knocking 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 = Behalf 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 few months.=20 =20 Brian Trubee __________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_0040_01CAC3BC.E38850B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Mike,
When you are down to 5 gallons, = remember that you=20 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=20 returned fuel enter the tank, at the root or up the tank aways. If up = the tank,=20 it takes a little time to flow back down to the inlet.
 
Something to consider.
Bill Schertz
KIS Cruiser=20 #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. Knowing=20 that both tanks were approaching (if not below) 5 gallons, it was the = first=20 thing I thought of and I looked at the ball. It was centered. And I'm = sure there=20 is going to turn out to be about 5 gallons left in the tank so its hard = to=20 understand how this could have been an issue with the pickup uncovering. = I just=20 don=92t have a better explanation. If the pump failed I would expect it = to stay=20 failed, not work fine on the ground.
 
I didn=92t copy it, but my system I believe is = the same=20 that Ian Beadle used. I have 1 pump for each tank. The outputs are T'eed = together - check valves built into the pumps prevents crossfeed. Both = tanks have=20 return lines. The return line from the fuel rail goes through an = industrial=20 grade electric valve.
 
I chose this design for a couple of=20 reasons:
1) Operational simplicity. I reasoned = that most=20 fuel related problems in flight are due to stupid pilot tricks so wanted = a=20 system that was as simple to operate as possible. In its original = configuration=20 all that was required to switch tanks was to flip a single toggle switch = on the=20 panel which would energize the appropriate pump and configure the return = valve=20 to return fuel to the tank it came from. This has since been modified = slightly=20 to have individual switches for each pump so both can be on at the same = time if=20 needed.
2) I had previous experience (bad) with EFI in = some=20 project cars before I built the airplane. I had a couple of fuel pump = failures=20 and in researching found strong recommendations against putting the fuel = pump=20 too far from the fuel tank. These pumps are designed to push fuel, not = draw=20 fuel. A design where both pumps have access to both tanks requires the = pumps to=20 be downstream of the fuel selector with several feet of fuel line ahead = of the=20 pump. I wanted to avoid this type of design although it apparently is = working=20 fine for Ed. My pumps are just inboard of the wing roots literally a = couple of=20 inches from the pickups in the tanks.
 
Tracy's system is mechanically simple but has = the=20 potential for pilot error resulting in pumping fuel overboard if the = transfer=20 pump is forgotten and left on. Yes, I know there are ways to address = that. And=20 clearly it works for him.
 
I think (thought?) I pretty well understand = the pros=20 and cons in my setup. All things being equal I think before = yesterday's=20 incident I would do it this way again. If it turns out that the = issue was=20 due to uncovering the pickup (not real sure how to prove that) I'd = consider=20 changing to include a header tank with a deep sump to prevent = re-occurance. But=20 I don=92t think I'd rely on suction to fill the header, think I'd use a = low=20 pressure pump like the typical Facet pump.
 
One thing is for certain. Unlike a carbureted = engine=20 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. Particularly = when=20 you are at the opposite corner of your test box from your home base. I = ended up=20 flying back about 70 miles hopscotching from field to = field.
 
Mike 

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

There is = certainly more=20 than one way to design a reliable fuel system =96 each with its pros and = cons.  I too did not want a six way value for switching fuel = between two=20 tanks and the engine with the ugh return line.  Besides I had = already=20 constructed my fuel system pretty much according to Van=92s = instructions.  So=20 to preclude a return line I came up with my =93almost returnless=94 = system.  It=20 uses a =BD pint capacity small header tank to return the injector fuel = =96 the fuel=20 injected to the engine comes from this header tank thereby creating a = =93vacuum=94=20 in the tank which pulls fresh fuel from the wing tanks.  It has = worked fine=20 for over 10 years.

 

Both fuel = pumps draw=20 from this header tank and either tank can feed it and I have no return = lines=20 going back to the tanks.

 

But, = Tracy=92s = approach has shown=20 to work just fine =96 not knocking it by any = means.

 

Ed

 

Ed=20 Anderson

Rv-6A N494BW=20 Rotary Powered

Matthews,=20 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.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in aircraft=20 [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Bktrub@aol.com
Sent: Friday, March 12, 2010 = 11:43=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: fuel = supply=20 problem?

 

I just = copied=20 Tracy's setup-=20 all fuel is pumped from the right tank, and fuel is transferred from the = left=20 into the right by a Facet pump. I didn't want to get into having a six = port fuel=20 valve in order to get the fuel injection to return to the tank I was = using at=20 the time.  

It's really = simple,=20 and hopefully that means reliable. We'll have to see, as this plane is = looking=20 for it's airworthiness inspection in the next few months.=20

 

Brian=20 Trubee



__________=20 Information from ESET NOD32 Antivirus, version of virus signature = database 3267=20 (20080714) __________

The message was checked by ESET NOD32=20 Antivirus.

http://www.eset.com

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