X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 11 Jun 2007 17:58:55 -0400 Message-ID: X-Original-Return-Path: Received: from wx-out-0506.google.com ([66.249.82.229] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2096932 for lml@lancaironline.net; Mon, 11 Jun 2007 16:00:09 -0400 Received-SPF: pass receiver=logan.com; client-ip=66.249.82.229; envelope-from=akadamson@gmail.com Received: by wx-out-0506.google.com with SMTP id t11so4965537wxc for ; Mon, 11 Jun 2007 12:59:31 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:from:to:references:subject:date:message-id:mime-version:content-type:x-mailer:x-mimeole:thread-index:in-reply-to:sender; b=aMFy9VeLUZjgQSrvefbfYtGtC15c33pAw9JOLCQw09xKsZNLP17hRPj8CP05RAG4gStwvcj0MeJ/4tZ4QR2AvEPJrmpbNwFElQ/JJw1NMVqkBq0yg8fKxLeLaLnr+CS8d8fZ3bRZwkwA05LkaQnhV5b6EzdW/wrURD+NeeOUWfg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:from:to:references:subject:date:message-id:mime-version:content-type:x-mailer:x-mimeole:thread-index:in-reply-to:sender; b=T9b0cAU9WRQCgIm2vSawylnCFB/qXJxTVgMygGuEECD/vX2g/E2IkIORhHFu7HcGCRe3Bn45R9BTHTwA9BH6e0SREb+6eQQ6hb/x0YHQp+ZHmLnsHuftnAStBaFzWPBXigivJWp+abeE3AqQ+xCS32YrBM11Y9L/2Bf82C4RC6w= Received: by 10.90.25.3 with SMTP id 3mr4736035agy.1181591971714; Mon, 11 Jun 2007 12:59:31 -0700 (PDT) X-Original-Return-Path: Received: from Typhoon ( [76.97.47.101]) by mx.google.com with ESMTP id 1sm8402734agb.2007.06.11.12.59.30 (version=SSLv3 cipher=RC4-MD5); Mon, 11 Jun 2007 12:59:31 -0700 (PDT) From: "Alan Adamson" X-Original-To: "'Lancair Mailing List'" References: Subject: RE: [Norton AntiSpam] [LML] Re: Boost switch X-Original-Date: Mon, 11 Jun 2007 15:59:30 -0400 X-Original-Message-ID: <001201c7ac63$06c17530$2201a8c0@highrf.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0013_01C7AC41.7FAFD530" X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 Thread-Index: AcesMX6OWb50dGFVSh2JCEV4YDD7wwALZoYA In-Reply-To: X-Original-Sender: Alan Adamson This is a multi-part message in MIME format. ------=_NextPart_000_0013_01C7AC41.7FAFD530 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit As it relates to all this fuel pump question/issue... Let's all make sure we are specific with a couple of things. Carl, was your failure in a TSIO or an IO engine? It seems there might be a difference in pump usage depending on either. The other thing to keep in mind is does anyone know the gph that can be supported with the pump alone in both settings? Regardless of type of engine? The *IO* needs approx 26-27gph at takeoff power settings, I suspect the TSIO will need a bit more but have no real world experience. *MAKING IT UP* - if the low boost setting will sustain 27gph (plus some acceptable margin) during an engine driven pump failure, then it could be used, or if it required high boost, then it would need that setting. So, given all of this, I picked up the phone and called Continental...Here's what they told me. They suggested that Low boost does nothing more than provide a "positive head pressure" to the engine driven pump, and that if you had an engine driven pump failure, it would most likely require "high boost" to provide not only the head pressure needed, but the volume needed to cause the engine to continue to run. I suspect there is "fudge factor" built into those assumptions. For example, there are probably different ways the engine driven pump can fail and depending on the failure mode, it seems that you *may* need more pressure from the external pump than others. This is probably why some have said that "low boost" is adequate, where others claim it requires "high boost". With that said, I'd offer the below, regardless of engine type. (continental specific) a) setup your fuel system appropriately, with the appropriate fuel flow for high power and the appropriate RPM rise for low power/idle - do this with a known working fuel system b) in *any sort of emergency*, it would appear that the first thing to do it reach for the "High Boost" setting. With a properly setup fuel system, it should not "flood out" the engine, but may be more fuel than is needed (and if so, the non-required fuel will be returned via the return fuel lines) c) once, adequate altitude has been determined, diagnosis could reveal that low boost is adequate to "get you home". I suspect there is a duty cycle that the external pump can support at HIGH vs.. LOW Boost and so if you can use low to get home, it probably makes sense to do so. d) if no emergency condition exists, it seems that Low boost may be used to avoid any "vapor" issues at 10K and above as most are taught/learned (I still don't know if this is a TSIO or IO specific learning, my guess is TSIO based upon fuel flow demands at high MP's) However the above raises 2 questions in my mind.... a) if High boost is critical in the event of an engine driven fuel pump failure, then I'd suggest we need to revise our "take off" procedures to include putting the pump in "High boost" or implement some form of "ARMED - relay switched" mode ala the Columbias. Fuel demands at TO are the most critical and because Continental suggests that if an engine driven pump failed, that you'd need high boost, it may make sense to revise ones procedures to have that available during TO b) it would also suggest that it is prudent to switch the pump to "Low boost" when switching tanks. This should maintain a more "constant" head pressure for the engine driven pump and avoid any "vapor/air bubble" issues when switching. I certainly wish there were more specific data around this topic, with specifics for the IO vs.. the TSIO, but the above does seem to make sense and offer the most "backup". Thots? Alan _____ From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Carl La Rue Sent: Monday, June 11, 2007 10:05 AM To: lml@lancaironline.net Subject: [Norton AntiSpam] [LML] Re: Boost switch Dan, high boost is more useful than engine prime. I had an engine fuel pump failure at 400 feet after takeoff from Port Columbus, OH, westbound towards city center. The engine immediately quit. I selected high boost and it immediately started. The engine-driven pump failure was confirmed by the Continental dealer who did the repair work. The boost pump did its job, IMHO. Carl La Rue On 6/6/07, Dan Ballin wrote: With the current discussion about the recent accident, I am curious what others have done with the fuel boost pump switch. It seems like the options are for separate switches for high and low, a 3 way Low - Off - High and with a 3 way with the High being momentary. I think I am favoring the later with the thinking that the high boost is really only needed during start for engine prime and as Skip stated this precludes leaving the high boost on. Other thoughts? Does this apply to the IO-550 as well? Do any of you flying, use the high boost for anything else. In an emergency would you use high or low boost or try both? I am doing a IO-550 in a Legacy. Dan Ballin LEG2 #286 -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html ------=_NextPart_000_0013_01C7AC41.7FAFD530 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
As it relates to all this fuel pump = question/issue... Let's=20 all make sure we are specific with a couple of things.  Carl, was = your=20 failure in a TSIO or an IO engine?  It seems there might be a = difference in=20 pump usage depending on either.  The other thing to keep in mind is = does=20 anyone know the gph that can be supported with the pump alone in both=20 settings?  Regardless of type of engine?  The *IO* needs = approx=20 26-27gph at takeoff power settings, I suspect the TSIO will need a bit = more but=20 have no real world experience.  *MAKING IT UP* - if the low boost = setting=20 will sustain 27gph (plus some acceptable margin) during an engine driven = pump=20 failure, then it could be used, or if it required high boost, then it = would need=20 that setting.
 
So, given all of this, I picked up the phone = and called=20 Continental...Here's what they told me.  They suggested that Low = boost does=20 nothing more than provide a "positive head pressure" to the engine = driven pump,=20 and that if you had an engine driven pump failure, it would most likely = require=20 "high boost" to provide not only the head pressure needed, but the = volume needed=20 to cause the engine to continue to run.
 
I suspect there is "fudge factor" built into = those=20 assumptions.  For example, there are probably different ways the = engine=20 driven pump can fail and depending on the failure mode, it seems that = you *may*=20 need more pressure from the external pump than others.  This is = probably=20 why some have said that "low boost" is adequate, where others claim it = requires=20 "high boost".
 
With that said, I'd offer the below, regardless = of engine=20 type. (continental specific)
 
a) setup your fuel system appropriately, with = the=20 appropriate fuel flow for high power and the appropriate RPM rise for = low=20 power/idle - do this with a known working fuel = system
b) in *any sort of emergency*, it would appear = that the=20 first thing to do it reach for the "High Boost" setting.  With a = properly=20 setup fuel system, it should not "flood out" the engine, but may be more = fuel=20 than is needed (and if so, the non-required fuel will be returned via = the return=20 fuel lines)
c) once, adequate altitude has been determined, = diagnosis=20 could reveal that low boost is adequate to "get you home".  I = suspect there=20 is a duty cycle that the external pump can support at HIGH vs.. LOW = Boost and so=20 if you can use low to get home, it probably makes sense to do=20 so.
d) if no emergency condition exists, it seems = that Low=20 boost may be used to avoid any "vapor" issues at 10K and above as most = are=20 taught/learned (I still don't know if this is a TSIO or IO specific = learning, my=20 guess is TSIO based upon fuel flow demands at high = MP's)
 
However the above raises 2 questions in my = mind....=20
 
a) if High boost is critical in the event of an = engine=20 driven fuel pump failure, then I'd suggest we need to revise our "take = off"=20 procedures to include putting the pump in "High boost" or implement some = form of=20 "ARMED - relay switched" mode ala the Columbias.  Fuel demands at = TO are=20 the most critical and because Continental suggests that if an engine = driven pump=20 failed, that you'd need high boost, it may make sense to revise ones = procedures=20 to have that available during TO
b) it would also suggest that it is prudent to = switch the=20 pump to "Low boost" when switching tanks.  This should maintain a = more=20 "constant" head pressure for the engine driven pump and avoid any = "vapor/air=20 bubble" issues when switching.
 
I certainly wish there were more specific data = around this=20 topic, with specifics for the IO vs.. the TSIO, but the above does seem = to make=20 sense and offer the most "backup".
 
Thots?
 
Alan
From: Lancair Mailing List=20 [mailto:lml@lancaironline.net] On Behalf Of Carl La = Rue
Sent:=20 Monday, June 11, 2007 10:05 AM
To:=20 lml@lancaironline.net
Subject: [Norton AntiSpam] [LML] Re: = Boost=20 switch

Dan, high boost is more useful than engine prime.  I had an = engine=20 fuel pump failure at 400 feet after takeoff from Port Columbus, OH, = westbound=20 towards city center.  The engine immediately quit.  I selected = high=20 boost and it immediately started.  The engine-driven pump failure = was=20 confirmed by the Continental dealer who did the repair work.  The = boost=20 pump did its job, IMHO.
 
Carl La Rue

 
On 6/6/07, Dan Ballin=20 <dballin@gmail.com> = wrote:=20
With=20 the current discussion about the recent accident, I am curious
what = others=20 have done with the fuel boost pump switch.  It seems like =
the=20 options  are for separate switches for high and low, a 3 way = Low=20 -
Off - High and with a 3 way with the High being = momentary.  I=20 think I
am favoring the  later with the thinking that the = high=20 boost is really
only needed during start for engine prime and as = Skip=20 stated this
precludes leaving the high boost on.
Other=20 thoughts?  Does this apply to the IO-550 as well?
Do any = of you=20 flying, use the high boost for anything else.  In an =
emergency=20 would you use high or low boost or try both?

I am doing a = IO-550 in a=20 Legacy.

Dan Ballin
LEG2
#286

--
For archives = and unsub=20 http://mail= .lancaironline.net:81/lists/lml/List.html

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