X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [64.4.51.86] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.3.2) with ESMTP id 968021 for flyrotary@lancaironline.net; Mon, 30 May 2005 14:40:14 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.4.51.86; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 30 May 2005 11:39:28 -0700 Message-ID: Received: from 64.4.51.220 by BAY107-DAV14.phx.gbl with DAV; Mon, 30 May 2005 18:39:28 +0000 X-Originating-IP: [64.4.51.220] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: will EFI pumps pump air was Re: Fuel Tank Selection Date: Mon, 30 May 2005 14:39:18 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00E9_01C56525.5EF05050" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Mon, 30 May 2005 14:39:23 -0400 X-OriginalArrivalTime: 30 May 2005 18:39:28.0831 (UTC) FILETIME=[E96D7CF0:01C56546] This is a multi-part message in MIME format. ------=_NextPart_000_00E9_01C56525.5EF05050 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Perry, what did you think of the physical configuration of=20 Paul's sump/header tank? (short, wide & narrow). Don't know if it was = a factor in the accident but another problem prone detail I think. Tracy ----- Original Message -----=20 From: Perry Mick=20 To: Rotary motors in aircraft=20 Sent: Monday, May 30, 2005 12:10 PM Subject: [FlyRotary] Re: will EFI pumps pump air was Re: Fuel Tank = Selection If that's the definition of a sump system, then I do not have a sump = system. I have a small EFI tank with two internal EFI pumps, fuel return = to this EFI tank. This EFI tank is located where the gascolator is in = the stock Long-EZ fuel system. I have the complete stock Long-EZ fuel = system otherwise with L-R-OFF selector (no BOTH). I will not refer to my = system as a sump system in the future, to avoid misconception (and = arguments). You've said it yourself Jim in the past, that you've had many problems = with your sump system. Maybe sump systems and BOTH selectors just don't = belong on Rutan derivatives, as RAF itself has said. As you saw, a = Lycoming-powered EZ had an accident in 1995 just after takeoff (sounds = like Paul?) with such a system. Jim S. wrote: A sump tank renders L-R(-B) selector redundant and superfluous. L and = R selectors allow the fuel pump to "suck" fuel from the selected tank. = When the tank is empty, you select the other tank. If you have "Both" = selected and one goes empty, the pump sucks air through that line. = Either way, the engine quits when one tank goes dry. You get power back = by selecting the tank that has fuel in it. The main disadvantage with a = "Both" position has to do with distraction and delay - when the engine = quits, you have to figure out which tank is dry and which way to turn = the knob to select the tank that has fuel. Takes time and is a definite = failure mode. Gravity feeding a sump through big enough lines = eliminates the need for valves. That's the main purpose of a sump. = Selectors are for when you don't have a sump. They have no place on a = system that does. The Rutan derivatives with a sump have no selector; = those with a selector have no sump. Paul's setup was unique. Just a theory ... Jim S. rijakits wrote: The only safe way to have a "Both"-selection for a low wing would be = (IMHO), to have a low pressure pump in each tank feed a fairly large = sump ( 2 gallons +) with a system as described by Georges below: EFI pump picking up at the bottom of the sump, with a return to the = top and baffels, not just separating the top from the bottom, but also = side from side, so when a tank pump starts to pump air into the sump, it = can vent to the top of the sump and out through the vent, which would = have to go to both main tanks. With some additional cross-feed line from one tank to the other with a = manual valve, one could use one tank pump as the back-up for the other: Open the crossfeed valve and slip the plane accordingly for a while. = That should push the fuel into the other tank, in case one of the pump = fails. One question remains: How would you prevent or equalize overflow from = the sump to the tanks? Thomas J. ----- Original Message -----=20 From: Echo Lake Fishing Resort (Georges = Boucher)=20 To: Rotary motors in aircraft=20 Sent: Sunday, May 29, 2005 8:07 PM Subject: [FlyRotary] Re: will EFI pumps pump air was Re: Fuel Tank = Selection Group FWIW Call it a sump or header tank, if its large enough say 3 liters oops! = I mean quarts with both pumps picking up fuel at the bottom 1/4 of the = tank with the fuel return pointing at the cover to avoid aerating the = fuel in the header (possibly a baffle below it & a vent pipe to each = tank) Gravity feed would work in a high wing , in a low wing I think you = still need a low pressure transfer pump to push fuel to the header tank = from the mains. I don't think it is safe to have "Both" position in the = fuel selector except in a gravity system with carburetors, not with EFI, = the possibility of "sucking air "is unavoidable without check valves ( = more weight, more cost & more possibility of problems). Georges B. ( Not really stirring the pot, maybe just a little) -------Original Message------- From: Rotary motors in aircraft Date: 05/29/05 17:42:01 To: Rotary motors in aircraft Subject: [FlyRotary] Re: will EFI pumps pump air was Re: Fuel Tank = Selection Now I'm not so worried, because each high pressure fuel pump draws from it's own tank and the only point of inter- connection = is where the lines join at the fuel rail(s). This brings up a question that I've had before, and I'm not sure this = is exactly what anyone is doing, so it's not meant that way. Say you have two tanks, with an EFI pump for each tank. You then = connect the output of each pump together, feeding into one line running = to the fuel rail. The question is: What happens when one tank runs = out of gas? Will the EFI pump move enough air through it to disturb the = fuel rail pressure that's being delivered from the other pump, or would = it just stop pumping at that point, and do no harm (other than maybe = burning the pump up eventually)? =20 Yep, still trying to figure out how to fix my fuel transfer system.=20 Cheers, Rusty >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_00E9_01C56525.5EF05050 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Perry, what did you think of the physical configuration of
Paul's sump/header tank? (short, wide & narrow).   = Don't know=20 if it was a factor in the accident but another problem prone detail I=20 think.
 
Tracy
----- Original Message -----
From: Perry Mick
To: Rotary motors in = aircraft
Sent: Monday, May 30, 2005 = 12:10 PM
Subject: [FlyRotary] Re: will = EFI pumps=20 pump air was Re: Fuel Tank Selection

If that's = the=20 definition of a sump system, then I do not have a sump system. I have = a small=20 EFI tank with two internal EFI pumps, fuel return to this EFI tank. = This EFI=20 tank is located where the gascolator is in the stock Long-EZ fuel = system. I=20 have the complete stock Long-EZ fuel system otherwise with L-R-OFF = selector=20 (no BOTH). I will not refer to my system as a sump system in the = future, to=20 avoid misconception (and arguments).

You've said it yourself = Jim in the=20 past, that you've had many problems with your sump system. Maybe sump = systems=20 and BOTH selectors just don't belong on Rutan derivatives, as RAF = itself has=20 said. As you saw, a Lycoming-powered EZ had an accident in 1995 just = after=20 takeoff (sounds like Paul?) with such a system.

Jim S.=20 wrote:

A sump tank renders L-R(-B) selector redundant and=20 superfluous.  L and R selectors allow the fuel pump to "suck" = fuel from=20 the selected tank.  When the tank is empty, you select the other=20 tank.  If you have "Both" selected and one goes empty, the pump = sucks air=20 through that line.  Either way, the engine quits when one tank = goes=20 dry.  You get power back by selecting the tank that has fuel in = it. =20 The main disadvantage with a "Both" position has to do with = distraction and=20 delay - when the engine quits, you have to figure out which tank is = dry and=20 which way to turn the knob to select the tank that has fuel.  = Takes time=20 and is a definite failure mode.  Gravity feeding a sump through = big=20 enough lines eliminates the need for valves.  That's the main = purpose of=20 a sump.  Selectors are for when you don't have a sump.  They = have no=20 place on a system that does.  The Rutan derivatives with a sump = have no=20 selector; those with a selector have no sump.  Paul's setup was=20 unique.
Just a theory ... Jim S.

rijakits wrote:
The only safe way to have a "Both"-selection for a low wing would = be=20 (IMHO), to have a low pressure pump in each tank feed a fairly large = sump ( 2=20 gallons +) with a system as described by Georges below:
EFI pump picking up at the bottom of the sump, with a return to = the top=20 and baffels, not just separating the top from the bottom, but also = side from=20 side, so when a tank pump starts to pump air into the sump, it can = vent to the=20 top of the sump and out through the vent, which would have to go to = both main=20 tanks.
With some additional cross-feed line from one tank to the other = with a=20 manual valve, one could use one tank pump as the back-up for the = other:
Open the crossfeed valve and slip the plane accordingly for a = while. That=20 should push the fuel into the other tank, in case one of the pump = fails.
One question remains: How would you prevent or equalize overflow = from the=20 sump to the tanks?
 
Thomas J.
----- Original Message -----
Sent: Sunday, May 29, 2005 8:07 PM
Subject: [FlyRotary] Re: will EFI pumps pump air was Re: = Fuel Tank=20 Selection

Group FWIW
Call it a sump or header tank, if its large enough say 3 liters = oops! I=20 mean quarts with both pumps picking up fuel at the bottom 1/4 of = the tank=20 with the fuel return pointing at the cover to avoid aerating the fuel = in the=20 header (possibly a baffle below it & a vent pipe to each tank) = Gravity=20 feed would work in a high wing , in a low wing I think you still need = a low=20 pressure transfer pump to  push fuel to the header tank from the = mains. I=20 don't think it is safe to have "Both" position in the fuel selector = except in=20 a gravity system with carburetors, not with EFI, the possibility = of=20 "sucking air "is unavoidable without check valves ( more weight, more = cost=20 & more possibility of problems).
Georges B. ( Not really stirring the pot, maybe just a = little)
 
-------Original = Message-------
 
Date: 05/29/05 17:42:01
Subject: [FlyRotary] Re: will EFI pumps = pump air=20 was Re: Fuel Tank Selection
 

   Now I'm not so worried, because each = high=20 pressure fuel
pump draws from it's own tank and the only point of = inter-=20 connection is where the lines join at the fuel rail(s).

 
This = brings up a=20 question that I've had before, and I'm not sure this is exactly what = anyone is=20 doing, so it's not meant that way.
 
Say = you have two=20 tanks, with an EFI pump for each tank.   You then = connect the=20 output of each pump together, feeding into one line running to the = fuel=20 rail.   The question is:  What happens when one = tank runs=20 out of gas?  Will the EFI pump move enough air through it to = disturb the=20 fuel rail pressure that's being delivered from the other pump, or = would it=20 just stop pumping at that point, and do no harm (other than maybe = burning the=20 pump up eventually)? 
 
Yep, still trying to figure = out how to fix=20 my fuel transfer system.
 
Cheers,
Rusty
 
 
 

>> =20 Homepage:  http://www.flyrotary.com/
>> =20 Archive:  =20 http://lancaironline.net/lists/flyrotary/List.html
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