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 4.3.4) with ESMTP id 1002962 for flyrotary@lancaironline.net; Wed, 15 Jun 2005 11:57:47 -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; Wed, 15 Jun 2005 08:57:01 -0700 Message-ID: Received: from 64.4.51.220 by BAY107-DAV14.phx.gbl with DAV; Wed, 15 Jun 2005 15:57:01 +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: fuel pump mounting ( fuel system architecture) Date: Wed, 15 Jun 2005 11:56:57 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0153_01C571A1.549E9700" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Wed, 15 Jun 2005 11:56:57 -0400 X-OriginalArrivalTime: 15 Jun 2005 15:57:01.0488 (UTC) FILETIME=[DE2AFB00:01C571C2] This is a multi-part message in MIME format. ------=_NextPart_000_0153_01C571A1.549E9700 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Just another thought on this subject. A common event in EFI cars that = get driven to empty tanks is that the pump runs dry for some time and = this can degrade its performance or ruin it. It would then not prime = unless force-fed some fuel because of the internal wear in the pump. An = orifice would help a worn pump to prime in this situation. This may be why there is such a variation of results we hear on this = list and elsewhere. =20 The bleeder orifice may be OK but I would worry about the condition of = the pump after an extended run-dry event. I always switch the pump off = immediately when this happens on my engine test stand. This also jogs my memory about the variation of fuel pressure between = the primary & backup pumps during tests with a blocked return. I think = it was Ed that mentioned this. =20 Tracy On Wed, 15 Jun 2005 09:02:49 -0500 David Staten = > writes: > > > I would be a little concerned about the pump being higher than the=20 > tank,=20 > given our recent discussions on vapor lock. Might work fine, but who = > knows.. > =20 > Dave --------------------------------------- Hi Dave, I hear you, but unless I'm sucking air in a leak between the tanks do not "think" it is a problem. You saw my comments about test during the 40 hour flyoff and have not experienced any difficulty yet. Not sure how high on the firewall that Ed's pumps are and know Tracy's are on the floor. Will be careful running tanks dry when I fly cross country to make = sure I'm with in gliding distance of an airstrip. Bernie >> Homepage: http://www.flyrotary.com/ >> Archive: = http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0153_01C571A1.549E9700 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Just another thought on this subject. A common event = in EFI cars=20 that get driven to empty tanks is that the pump runs dry for some = time and=20 this can degrade its performance or ruin it. It would then = not prime=20 unless force-fed some fuel because of the internal wear in the = pump. An orifice would help a worn pump to prime in this = situation.

This may be why there is such a variation of results we hear on = this list=20 and elsewhere.

The bleeder orifice may be OK but I would worry about the condition = of the=20 pump after an extended run-dry event. I always switch the pump off = immediately when this happens on my engine test stand.

This also jogs my memory about the variation of fuel pressure = between the=20 primary & backup pumps during tests with a blocked return. I = think it=20 was Ed that mentioned this.

Tracy

On=20 Wed, 15 Jun 2005 09:02:49 -0500 David Staten <Dastaten@earthlink.net>
= writes:
>=20 >
> I would be a little concerned about the pump being higher = than=20 the
> tank,
> given our recent discussions on vapor = lock. Might=20 work fine, but who
> knows..
>
>=20 Dave
---------------------------------------

Hi Dave, I hear = you,=20 but unless I'm sucking air in a leak between the
tanks do not = "think" it is=20 a problem. You saw my comments about test
during the 40 hour flyoff = and=20 have not experienced any difficulty yet.
Not sure how high on the = firewall=20 that Ed's pumps are and know Tracy's
are on the floor.

Will = be=20 careful running tanks dry when I fly cross country to make sure
I'm = with in=20 gliding distance of an airstrip.

Bernie

>> =20 Homepage: http://www.flyrotary.com/
>&= gt; =20 Archive: http://lancai= ronline.net/lists/flyrotary/List.html

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