X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from qmta06.emeryville.ca.mail.comcast.net ([76.96.30.56] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4165521 for flyrotary@lancaironline.net; Sun, 14 Mar 2010 16:34:51 -0400 Received-SPF: pass receiver=logan.com; client-ip=76.96.30.56; envelope-from=hoursaway1@comcast.net Received: from omta14.emeryville.ca.mail.comcast.net ([76.96.30.60]) by qmta06.emeryville.ca.mail.comcast.net with comcast id t72j1d0071HpZEsA68aF9c; Sun, 14 Mar 2010 20:34:15 +0000 Received: from sz0081.ev.mail.comcast.net ([76.96.26.137]) by omta14.emeryville.ca.mail.comcast.net with comcast id t8aF1d0012xV6SL8a8aF5v; Sun, 14 Mar 2010 20:34:15 +0000 Date: Sun, 14 Mar 2010 20:34:15 +0000 (UTC) From: hoursaway1@comcast.net To: Rotary motors in aircraft Message-ID: <4852243.14867881268598855112.JavaMail.root@sz0081a.emeryville.ca.mail.comcast.net> In-Reply-To: Subject: Re: [FlyRotary] Re: fuel supply problem? MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_803038_1963720409.1268598855110" X-Originating-IP: [76.20.183.210] X-Mailer: Zimbra 5.0.19_GA_3172.RHEL5_64 (ZimbraWebClient - IE6 (Win)/5.0.19_GA_3177.RHEL5_64) ------=_Part_803038_1963720409.1268598855110 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Use a borescope to look into your tanks Mike, a lot easyer, I found a cheap= one with a 1/4" fib. optic wand, slips up into the drain hole even with th= e stiff wire taped to it bent into a 90 deg. curve, someone at the airport = or EAA chapter should have one or your friendly local auto-tech might loan = you one.=C2=A0=C2=A0David R. Cook=C2=A0 RV6A Rotary.=20 ----- Original Message -----=20 From: "Mike Wills" =20 To: "Rotary motors in aircraft" =20 Sent: Saturday, March 13, 2010 11:03:42 PM GMT -05:00 US/Canada Eastern=20 Subject: [FlyRotary] Re: fuel supply problem?=20 Tracy,=20 =C2=A0I do have filters between tanks and pumps. I had an issue early on wi= th junk in the=C2=A0filters but never enough to cause any issue. This was j= ust a little construction debris and remnants of some automotive sealant I = initially used to install the access plates (since reinstalled with Proseal= ).=C2=A0I just did my first condition inspection and checked the=C2=A0filte= rs about a month ago and they were clean. But I will check them again.=20 Never have had a problem previously with pressure drop across the filter. T= he problem happened=C2=A0at about the 1.3 hour point in=C2=A0the flight. At= the time I was motoring around at 8500' and at a pretty low power setting = - EFISM said fuel flow was about 7.8 GPH. I did run it up to full power on = the ground and couldn=E2=80=99t duplicate.=20 My pickups have a screen and have the Vans required anti-rotation tab rivet= ed to the access cover plate. But I suppose if I cant attribute it to anyth= ing else I should probably pull the tank and make sure the pickup hasn=E2= =80=99t moved. Man that sounds like a lot of work.=20 Mike =C2=A0=C2=A0=20 From: Tracy Crook=20 Sent: Saturday, March 13, 2010 10:35 AM=20 To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: fuel supply problem?=20 I had a similar thing happen but the engine would recover when I reduced th= rottle.=C2=A0 Problem was clogged filter between tank and pump.=C2=A0 At lo= w flow rate all was OK but pressure drop across filter at high flow rate ca= used pump to cavitate and fuel pressure to drop.=C2=A0 Did you try high thr= ottle on ground test later?=20 But you didn't mention a filter between tank & pump.=C2=A0 That has potenti= al problems as well since it doesn't take much trash to foul up an EFI pump= & might have cleared up after it passed.=C2=A0 Do you have only the slots = in Van's suggested tank pickup between tank & pump?=C2=A0 Problem might hav= e been trash going through pump.=20 I guess Ed already mentioned the loose tank pickup problem he had.=20 Tracy=20 On Sat, Mar 13, 2010 at 11:29 AM, Mike Wills < rv-4mike@cox.net > wrote:=20 I'm pretty sure the turn was coordinated.=C2=A0Knowing 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 t= urn out to be about 5 gallons left in the tank so its hard to understand ho= w 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 Bead= le used. I have 1 pump for each tank. The outputs are T'eed together - chec= k valves built into the pumps prevents crossfeed. Both tanks have return li= nes. The return line from the fuel rail goes through an industrial grade el= ectric valve.=20 I chose this design for a couple of reasons:=20 1)=C2=A0Operational simplicity. I reasoned that most fuel related problems = in flight are due to stupid pilot tricks so wanted a system that was as sim= ple 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 retur= n fuel to the tank it came from. This has since been modified slightly to h= ave individual switches for each pump so both can be on at the same time if= needed.=20 2) I had previous experience (bad) with EFI in some project cars before I b= uilt 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 downstr= eam 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 fin= e for Ed. My pumps are just inboard of the wing roots literally a couple of= inches from the pickups in the tanks.=20 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 f= or him.=20 I think (thought?) I pretty well understand the pros and=C2=A0cons in my se= tup. All things being equal I think before yesterday's incident I would do = it this way again.=C2=A0If it turns out that the issue was due to uncoverin= g the pickup (not real sure how to prove that) I'd consider changing to inc= lude 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 p= ressure pump like the typical Facet pump.=20 One thing is for certain. Unlike a carbureted engine which has a little cus= hion due to fuel in a float bowl, the instant fuel pressure drops this engi= ne quits. It's an attention getter. Particularly when you are at the opposi= te corner of your test box from your home base. I ended up flying back abou= t 70 miles hopscotching from field to field.=20 Mike =C2=A0=20 From: Ed Anderson=20 Sent: Saturday, March 13, 2010 1:53 AM=20 To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: fuel supply problem?=20 There is certainly more than one way to design a reliable fuel system =E2= =80=93 each with its pros and cons.=C2=A0 I too did not want a six way valu= e for switching fuel between two tanks and the engine with the ugh return l= ine.=C2=A0 Besides I had already constructed my fuel system pretty much acc= ording to Van=E2=80=99s instructions.=C2=A0 So to preclude a return line I = came up with my =E2=80=9Calmost returnless=E2=80=9D system.=C2=A0 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 cre= ating a =E2=80=9Cvacuum=E2=80=9D in the tank which pulls fresh fuel from th= e wing tanks.=C2=A0 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 kno= cking it by any means.=20 Ed=20 Ed Anderson=20 Rv-6A N494BW Rotary Powered=20 Matthews, NC=20 eanderson@carolina.rr.com=20 http://www.andersonee.com=20 http://www.dmack.net/mazda/index.html=20 http://www.flyrotary.com/=20 http://members.cox.net/rogersda/rotary/configs.htm#N494BW=20 http://www.rotaryaviation.com/Rotorhead%20Truth.htm=20 From: Rotary motors in aircraft [mailto: flyrotary@lancaironline.net ] On B= ehalf Of Bktrub@aol.com=20 Sent: Friday, March 12, 2010 11:43 PM=20 To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: fuel supply problem?=20 I just copied Tracy's setup- all fuel is pumped from the right tank, and fu= el is transferred from the left into the right by a Facet pump. I didn't wa= nt to get into having a six port fuel valve in order to get the fuel inject= ion to return to the tank I was using at the time.=C2=A0=C2=A0=20 It's really simple, and hopefully that means reliable. We'll have to see, a= s this plane is looking for it's airworthiness inspection in the next few m= onths.=20 Brian Trubee=20 __________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 3267 (20080714) __________=20 The message was checked by ESET NOD32 Antivirus.=20 http://www.eset.com=20 ------=_Part_803038_1963720409.1268598855110 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable <= div style=3D'font-family: Arial; font-size: 12pt; color: #000000'>Use a bor= escope to look into your tanks Mike, a lot easyer, I found a cheap one with= a 1/4" fib. optic wand, slips up into the drain hole even with the stiff w= ire taped to it bent into a 90 deg. curve, someone at the airport or EAA ch= apter should have one or your friendly local auto-tech might loan you one.&= nbsp; David R. Cook  RV6A Rotary.
----- Original Message -----=
From: "Mike Wills" <rv-4mike@cox.net>
To: "Rotary motors in ai= rcraft" <flyrotary@lancaironline.net>
Sent: Saturday, March 13, 20= 10 11:03:42 PM GMT -05:00 US/Canada Eastern
Subject: [FlyRotary] Re: fue= l supply problem?

Tracy,
 
 I do have filters between tanks and pumps. = I had an issue early on with junk in the filters but never enough to c= ause any issue. This was just a little construction debris and remnants of = some automotive sealant I initially used to install the access plates (sinc= e reinstalled with Proseal). I just did my first condition inspection = and checked the filters about a month ago and they were clean. But I w= ill check them again.
 
Never have had a problem previously with pressure= drop across the filter. The problem happened at about the 1.3 hour po= int in the flight. At the time I was motoring around at 8500' and at a= pretty low power setting - EFISM said fuel flow was about 7.8 GPH. I did r= un it up to full power on the ground and couldn=E2=80=99t duplicate.=
 
My pickups have a screen and have the Vans requir= ed anti-rotation tab riveted to the access cover plate. But I suppose if I = cant attribute it to anything else I should probably pull the tank and make= sure the pickup hasn=E2=80=99t moved. Man that sounds like a lot of work.<= /FONT>
 
Mike  

Sent: Saturday, March 13, 2010 10:35 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: fuel supply problem?

I had a similar thing happen but the engine would recover wh= en I reduced throttle.  Problem was clogged filter between tank and pu= mp.  At low flow rate all was OK but pressure drop across filter at hi= gh flow rate caused pump to cavitate and fuel pressure to drop.  Did y= ou try high throttle on ground test later?

But you didn't mention a = filter between tank & pump.  That has potential problems as well s= ince it doesn't take much trash to foul up an EFI pump & might have cle= ared up after it passed.  Do you have only the slots in Van's suggeste= d tank pickup between tank & pump?  Problem might have been trash = going through pump.

I guess Ed already mentioned the loose tank pick= up problem he had.
Tracy

On Sat, Mar 13, 2010 at 11:29 AM, Mike Wills <rv-4mike= @cox.net> wrote:
I'm pretty sure the turn was coordinated. Kn= owing 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 u= ncovering. I just don=E2=80=99t have a better explanation. If the pump fail= ed I would expect it to stay failed, not work fine on the ground.
 
I didn=E2=80=99t 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 thro= ugh an industrial grade electric valve.
 
I chose this design for a couple of reasons:
1) Operational simplicity. I reasoned that m= ost fuel related problems in flight are due to stupid pilot tricks so wante= d a system that was as simple to operate as possible. In its original confi= guration 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 b= een 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 so= me project cars before I built the airplane. I had a couple of fuel pump fa= ilures 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 requir= es the pumps to be downstream of the fuel selector with several feet of fue= l 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 r= oots 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 trans= fer pump is forgotten and left on. Yes, I know there are ways to address th= at. And clearly it works for him.
 
I think (thought?) I pretty well understand the p= ros and cons in my setup. All things being equal I think before yester= day'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 heade= r, think I'd use a low pressure pump like the typical Facet pump.
 
One thing is for certain. Unlike a carbureted eng= ine which has a little cushion due to fuel in a float bowl, the instant fue= l 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 

Sent: Saturday, March 13, 2010 1:53 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: fuel supply problem?

There is certainly mo= re than one way to design a reliable fuel system =E2=80=93 each with its pr= os and cons.  I too did not want a six way value for switching fuel be= tween two tanks and the engine with the ugh return line.  Besides I ha= d 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 t= o 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 tanks.  It = has worked fine for over 10 years.

 <= /P>

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

 <= /P>

But, Tracy=E2=80=99s = approach has shown to work just fine =E2=80=93 not knocking it by any means= .

 <= /P>

Ed

 <= /P>

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 p= roblem?

 

I just copied Tracy'= s setup- all fuel is pumped from the right tank, and fuel is transferred fr= om the left into the right by a Facet pump. I didn't want to get into havin= g 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 simple, = and hopefully that means reliable. We'll have to see, as this plane is look= ing for it's airworthiness inspection in the next few months.

 =

Brian Trubee<= /FONT>



__________ I= nformation from ESET NOD32 Antivirus, version of virus signature database 3= 267 (20080714) __________

The message was checked by ESET NOD32 Anti= virus.

http://www.e= set.com


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