X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-oa0-f46.google.com ([209.85.219.46] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6638231 for lml@lancaironline.net; Fri, 13 Dec 2013 16:35:14 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.46; envelope-from=billhogarty@gmail.com Received: by mail-oa0-f46.google.com with SMTP id o6so2712205oag.33 for ; Fri, 13 Dec 2013 13:34:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=YP/4VjBX8pUmEmsDs86ASunAkUG45kjgO32JOrgokXU=; b=RBy1jRRJGnxySJqHHs01TWDA3ItAn8pSLV1zUewwX6385HzIl8sUJ43+VaqO3to0KU Ct9HNNqHBaX31siKvury3kfR6gO6zBHgPYGNrPdaLhPk0ljwp+dPB+aG/xGpq2JJZZQl Rt+DbBYasMUwvX20pN44ISK9Kug5jFoHERMY4ZfFYRxXgwpxWIkiSyScfrsHbI1BDZDU sHCpahKdDu4o9IEIMl8XWNJjnrPv4UMH1UvWLM4geU34d4jScP22sM9mv7X3x/S3sHEx kbu5+sdnGVbiOm0VqxHAtpAyJUQomzp49lr+K7JyH/k6mldi8bDye1x0B41tfEo7N80Z RiPg== MIME-Version: 1.0 X-Received: by 10.182.246.39 with SMTP id xt7mr3349112obc.16.1386970479387; Fri, 13 Dec 2013 13:34:39 -0800 (PST) Received: by 10.182.225.169 with HTTP; Fri, 13 Dec 2013 13:34:39 -0800 (PST) In-Reply-To: References: Date: Fri, 13 Dec 2013 13:34:39 -0800 Message-ID: Subject: Re: [LML] Re: Engine surging From: "William A. Hogarty" To: Lancair Mailing List Content-Type: multipart/alternative; boundary=001a11c2e224bceb1904ed713a10 --001a11c2e224bceb1904ed713a10 Content-Type: text/plain; charset=ISO-8859-1 Art: My guess is that the boost pump is picking up a small amount of air (loose/bad connection) and the engine doesn't like it. Good Luck Bill Hogarty On Thu, Dec 12, 2013 at 7:16 PM, Colyn Case wrote: > Art, > > on my IV-P the fuel flow actually decreases slightly with the electric > fuel pump on. > did you watch fuel flow (and fuel pressure if you have it) while you were > doing this? > > Colyn > > On Oct 2, 2013, at 7:48 AM, Bill Bradburry wrote: > > Art, > > Explain this phenomenon to the guys at GAMI. I bet they can explain what > is > happening to your engine. > http://www.gami.com/contact/contact.php > > B2 > > > -----Original Message----- > From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Art > Jensen > Sent: Tuesday, October 01, 2013 2:57 PM > To: lml@lancaironline.net > Subject: [LML] Re: Engine surging > > Charley, > The surging was first noticed after take-off with low boost ON at about 800 > feet AGL leaned for altitude 2500 RPM WOT. Being under the KFTG TCA climbs > were in steps to 9500 MSL where I leveled off to try to understand what's > going on and see how changes in operation affected what I was seeing and > feeling. I reduced power and went LOP same results. Then turned off the low > boost and the surging stopped. The engine ran very smooth. Turned the low > boost back on and the surging came back. Again I turned it off and it went > away. I determined I had found the cause (fuel pump) but still don't > understand why (what is beginning to fail) or the connection (how it plays > a > roll to create the results I experienced). > > Still looking for the expert who can put it all together so that I can come > up with a plan of action for repair. > > Called Lancair to price a new Dukes Fuel Pump, $3350, might be a bargain > tomorrow but at that price I'm not going to R&R as a test. Haven't checked > a > price for overhaul assuming my problem is in fact the pump. > > Any and all advice appreciated. > > Art > > Sent from my iPhone; Art Jensen > > > On Oct 1, 2013, at 1:30 AM, Charles Brown wrote: > > > > Just a thought ... if there wasn't any rpm change, and you heard or felt > surging, it could be a torque increase that causes a pitch increase, and > increased thrust. And if MP was constant, then the only thing *that* > leaves > is mixture. If you're running lean of peak, power depends significantly on > mixture. > > > > The thing is, this sounds backwards. If it's worse when you turn the > boost pump ON, then it sorta seems that you were running so far rich of > peak > that additional fuel pressure degraded power? I'm not aware that the > engine > can even produce a mixture that overrich, except at very low power > settings. > > Charley > > > > On Sep 30, 2013, at 7:58 AM, Art Jensen wrote: > > > > Looking for thoughts from the collective minds of the LML. Last flight > in > my IO-550 normally aspirated legacy, I noticed surging in the engine with > the low boost pump on. I did not notice any surging when I turned the boost > pump off. Also did not notice any fluctuation in RPM. Nor did I see any > fluctuation in RPM when I downloaded the engine data. The obvious question > would be what are the possible causes and does it make the airplane unsafe > for flight as there is no surge when the boost pump is off. I don't > understand how I could feel and hear surging in the engine yet see no > fluctuation in RPM, so I'm stumped. Any ideas would be appreciated, thank > you. > > Art > > > > Sent from my iPhone; Art Jensen > > -- > > For archives and unsub > http://mail.lancaironline.net:81/lists/lml/List.html > > > > > > -- > > For archives and unsub > http://mail.lancaironline.net:81/lists/lml/List.html > > -- > For archives and unsub > http://mail.lancaironline.net:81/lists/lml/List.html > > > -- > For archives and unsub > http://mail.lancaironline.net:81/lists/lml/List.html > > > -- > For archives and unsub > http://mail.lancaironline.net:81/lists/lml/List.html > --001a11c2e224bceb1904ed713a10 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Art:

My guess is that the bo= ost pump is picking up a small amount of air (loose/bad connection) and the= engine doesn't like it.

Good Luck

Bill Hogarty


<= div class=3D"gmail_quote">On Thu, Dec 12, 2013 at 7:16 PM, Colyn Case <colyncase@earthlink.net> wrote:
Art,

on my IV-P the fuel flow actually decreases slightly with the electric fuel= pump on.
did you watch fuel flow (and fuel pressure if you have it) while you were d= oing this?

Colyn

On Oct 2, 2013, at 7:48 AM, Bill Bradburry wrote:

Art,

Explain this phenomenon to the guys at GAMI. =A0I bet they can explain what= is
happening to your engine.
http:= //www.gami.com/contact/contact.php

B2


-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Art
Jensen
Sent: Tuesday, October 01, 2013 2:57 PM
To: lml@lancaironline.net
Subject: [LML] Re: Engine surging

Charley,
The surging was first noticed after take-off with low boost ON at about 800=
feet AGL leaned for altitude 2500 RPM WOT. Being under the KFTG TCA climbs<= br> were in steps to 9500 MSL where I leveled off to try to understand what'= ;s
going on and see how changes in operation affected what I was seeing and feeling. I reduced power and went LOP same results. Then turned off the low=
boost and the surging stopped. The engine ran very smooth. Turned the low boost back on and the surging came back. Again I turned it off and it went<= br> away. I determined I had found the cause (fuel pump) but still don't understand why (what is beginning to fail) or the connection (how it plays = a
roll to create the results I experienced).

Still looking for the expert who can put it all together so that I can come=
up with a plan of action for repair.

Called Lancair to price a new Dukes Fuel Pump, $3350, might be a bargain tomorrow but at that price I'm not going to R&R as a test. Haven= 9;t checked a
price for overhaul assuming my problem is in fact the pump.

Any and all advice appreciated.

Art

Sent from my iPhone; Art Jensen

> On Oct 1, 2013, at 1:30 AM, Charles Brown <browncc1@verizon.net> wrote:
>
> Just a thought ... if there wasn't any rpm change, and you heard o= r felt
surging, it could be a torque increase that causes a pitch increase, and increased thrust. =A0And if MP was constant, then the only thing *that* lea= ves
is mixture. =A0If you're running lean of peak, power depends significan= tly on
mixture.
>
> The thing is, this sounds backwards. =A0If it's worse when you tur= n the
boost pump ON, then it sorta seems that you were running so far rich of pea= k
that additional fuel pressure degraded power? =A0I'm not aware that the= engine
can even produce a mixture that overrich, except at very low power settings= .
> Charley
>
> On Sep 30, 2013, at 7:58 AM, Art Jensen wrote:
>
> Looking for thoughts from the collective minds of the LML. =A0Last fli= ght in
my IO-550 normally aspirated legacy, I noticed surging in the engine with the low boost pump on. I did not notice any surging when I turned the boost=
pump off. Also did not notice any fluctuation in RPM. Nor did I see any
fluctuation in RPM when I downloaded the engine data. The obvious question<= br> would be what are the possible causes and does it make the airplane unsafe<= br> for flight as there is no surge when the boost pump is off. I don't
understand how I could feel and hear surging in the engine yet see no
fluctuation in RPM, so I'm stumped. Any ideas would be appreciated, tha= nk
you.
> Art
>
> Sent from my iPhone; Art Jensen
> --
> For archives and unsub
http://mail.lancaironline.net:81/lists/lml/List.html
>
>
> --
> For archives and unsub
http://mail.lancaironline.net:81/lists/lml/List.html

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