X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 21 Feb 2008 11:51:06 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m23.mx.aol.com ([64.12.137.4] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2750109 for lml@lancaironline.net; Wed, 20 Feb 2008 16:59:22 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.4; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m23.mx.aol.com (mail_out_v38_r9.3.) id q.bcd.20777603 (29678) for ; Wed, 20 Feb 2008 16:58:35 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Wed, 20 Feb 2008 16:58:34 EST Subject: Re: [LML] LNC2 Boost Pump/Gascolator X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1203544714" X-Mailer: Unknown sub 34 X-Spam-Flag: NO -------------------------------1203544714 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Angier, My gascolator and boost pump are in the same general area with no cooling shroud. My engine driven pump is attached to the hot engine in a hot location on the hot side of the cooling plenum where it is hot. In stop and go taxiing and idling on a hot day I have receiving warnings that the fuel pressure had dropped below 12 psi. This is probably a result of the vaporization of fuel and consequent pump cavitation in the engine driven pump that might have been a bit warm. This problem is always resolved by flipping on the boost pump (it is getting warmed fuel from the gascolator) and either clearing the problem immediately or leaving the boost pump on until it is no longer needed. Hot starts have a similar problem because of the heat soaked engine driven pump. This problem is reduced by running the boost pump (even with the mixture at idle cutoff) in order to raise the fuel pressure and put some of the vapor back into solution. In "hot" weather (above 70F), the boost pump is turned on during takeoff and initial climb. It is also turned on during the downwind (or approach) and left on until I am off the runway. My engine temps are not too high during these operations (CHTs under 380F, oil under 210F). Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Pilot not TSO'd, Certificated score only > 70%. In a message dated 2/20/2008 2:22:19 P.M. Central Standard Time, N4ZQ@comcast.net writes: As we all know, everything's a pretty tight fit firewall forward. Given the low 130 +/- degree boiling point of 100LL, I'm wondering if I should enclosed the boost pump/gascolator in a shroud with cold air directed to it. I suppose it's possible with low power on a hot day and short final, fuel could start to vaporize in this part of the fuel system resulting in engine stoppage at just the wrong time. Of course the boost pump would be on at this point, but are any of this group aware of an instance of power loss due to vaporization at low power settings? **************Ideas to please picky eaters. Watch video on AOL Living. (http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/ 2050827?NCID=aolcmp00300000002598) -------------------------------1203544714 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Angier,
 
My gascolator and boost pump are in the same general area with no=20 cooling shroud.
 
My engine driven pump is attached to the hot engine in a hot location o= n=20 the hot side of the cooling plenum where it is hot.
 
In stop and go taxiing and idling on a hot day I have receiving=20 warnings that the fuel pressure had dropped below 12 psi.  This is prob= ably=20 a result of the vaporization of fuel and consequent pump=20 cavitation in the engine driven pump that might have been a bit=20 warm.  This problem is always resolved by flipping on the boost pump (i= t is=20 getting warmed fuel from the gascolator) and either clearing the problem=20 immediately or leaving the boost pump on until it is no longer needed. = =20
 
Hot starts have a similar problem because of the heat soaked engine dri= ven=20 pump.  This problem is reduced by running the boost pump (even with the= =20 mixture at idle cutoff) in order to raise the fuel pressure and pu= t=20 some of the vapor back into solution.
 
In "hot" weather (above 70F), the boost pump is turned on during=20 takeoff and initial climb.  It is also turned on during the downwind (o= r=20 approach) and left on until I am off the runway.
 
My engine temps are not too high during these operations (CHTs under 38= 0F,=20 oil under 210F).
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Pil= ot=20 not TSO'd, Certificated score only > 70%.
 
In a message dated 2/20/2008 2:22:19 P.M. Central Standard Time,=20 N4ZQ@comcast.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>As we=20 all know, everything's a pretty tight fit firewall forward.
Given the l= ow=20 130 +/- degree boiling point of 100LL, I'm wondering if 
I should= =20 enclosed the boost pump/gascolator in a shroud with cold air =20
directed to it.

I suppose it's possible with low power on a hot= day=20 and short final, 
fuel could start to vaporize in this part of th= e=20 fuel system resulting 
in engine stoppage at just the wrong time.= Of=20 course the boost pump 
would be on at this point, but are any of=20= this=20 group aware of an 
instance of power loss due to vaporization at=20= low=20 power settings?
 



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