X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 19 Jun 2009 12:21:35 -0400 Message-ID: X-Original-Return-Path: Received: from smtp-auth-02.mx.pitdc1.expedient.net ([206.210.66.135] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTPS id 3687767 for lml@lancaironline.net; Thu, 18 Jun 2009 23:05:56 -0400 Received-SPF: none receiver=logan.com; client-ip=206.210.66.135; envelope-from=rpastusek@htii.com Received: from HTBOB001 (static-71-178-198-10.washdc.fios.verizon.net [71.178.198.10]) by smtp-auth-02.mx.pitdc1.expedient.net (Postfix) with ESMTPA id F121A86CE8 for ; Thu, 18 Jun 2009 23:05:22 -0400 (EDT) From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Boost pump question X-Original-Date: Thu, 18 Jun 2009 23:05:19 -0400 X-Original-Message-ID: <041201c9f08a$c797d7a0$56c786e0$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0413_01C9F069.408637A0" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcnwFfwFVsn3/16aRGeNVmmeft/OgwAcfdUg Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_0413_01C9F069.408637A0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Dan Reagan writes: . when I am rewiring the fuel pump, do I need both the high and the low speeds? My dumb question of the day is, when is the fuel pump supposed to be used on the TSIO550 in the Lancair IVP? Dan, I was advised by several owner/fliers to run the boost pump in "low" speed above 10,000'--only. A good friend with lots of experience in Lancair IV-P's runs his fuel pump on low at all times. I have chosen the former route, and have an altitude/pressure switch hooked to a light that reminds me to switch to low boost when passing 10,000' climbing, and to turn it off when descending. I have set up the engine to flow 43 GPH at 2700 RPM and 38.5" MP on takeoff with the boost pump off. Turning on the low boost raises the fuel flow about 2 GPH at max power, but high boost increases it so much that the engine floods/quits-48 GPH or so. I intentionally left the low boost off after heat soaking at an airshow during climb out two weeks ago. The engine rolled back at about 14,000' and the fuel flow was erratic (I did not look at the pressure, but will do so if it happens again.) I turned the boost pump to low and the engine recovered almost immediately. So for my money; boost pump off for all operations below 10,000', and on above. Keep high boost for purging/starting, and any time you have fuel starvation, such as vaporization or loss of the engine pump. Expect to have to modulate the fuel flow manually with the mixture control any time you're running high boost. Views of others? Bob ------=_NextPart_000_0413_01C9F069.408637A0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Dan Reagan writes:

… when I am = rewiring the fuel pump, do I need both the high and the low speeds?  My dumb question of the day is, when is the fuel pump supposed to be used = on the TSIO550 in the Lancair IVP?

 

Dan,

I was advised by several owner/fliers to run the boost = pump in “low” speed above 10,000’--only. A good friend with lots of experience = in Lancair IV-P’s runs his fuel pump on low at all times. I have = chosen the former route, and have an altitude/pressure switch hooked to a light = that reminds me to switch to low boost when passing 10,000’ climbing, = and to turn it off when descending.

 

I have set up the engine to flow 43 GPH at 2700 RPM and = 38.5” MP on takeoff with the boost pump off. Turning on the low boost raises = the fuel flow about 2 GPH at max power, but high boost increases it so much that = the engine floods/quits—48 GPH or so.

 

I intentionally left the low boost off after heat soaking = at an airshow during climb out two weeks ago. The engine rolled back at about = 14,000’ and the fuel flow was erratic (I did not look at the pressure, but will = do so if it happens again…) I turned the boost pump to low and the = engine recovered almost immediately…

 

So for my money; boost pump off for all operations below = 10,000’, and on above. Keep high boost for purging/starting, and any time you = have fuel starvation, such as vaporization or loss of the engine pump. Expect to = have to modulate the fuel flow manually with the mixture control any time = you’re running high boost…

 

Views of others?

 

Bob

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