X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 27 Jan 2012 13:40:37 -0500 Message-ID: X-Original-Return-Path: Received: from raven.ravenwebhosting.com ([72.9.254.67] verified) by logan.com (CommuniGate Pro SMTP 5.4.3) with ESMTPS id 5367171 for lml@lancaironline.net; Fri, 27 Jan 2012 12:31:23 -0500 Received-SPF: none receiver=logan.com; client-ip=72.9.254.67; envelope-from=paul@tbm700.com Received: from 216.192.189.72.cfl.res.rr.com ([72.189.192.216]:62116 helo=[192.168.1.103]) by raven.ravenwebhosting.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.69) (envelope-from ) id 1RqpdP-00004r-1x for lml@lancaironline.net; Fri, 27 Jan 2012 12:30:47 -0500 From: paul miller Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-15--661590860 Subject: Re: [LML] Re: Steam Gauge Backup X-Original-Date: Fri, 27 Jan 2012 12:30:43 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1084) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - raven.ravenwebhosting.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tbm700.com X-Source: X-Source-Args: X-Source-Dir: --Apple-Mail-15--661590860 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii In a past life I went through a lot of dry pumps on the twin Cessna. We = did a lot of testing and found some easy ways to extend life. To test, = we turned a pump with a motor in the shop to see the temperatures. The = pump without airflow will get VERY hot and needs external airflow. Once = we ducted airflow with those addon plastic housings, life was extended = on the airframe. Also, we disassembled worn pumps and found the carbon = blades worn at the edges and getting thin. Turning the pump backwards = broke some of those blades. This means that if you have someone turning = your prop backwards on a worn pump, it might lead to premature failure. = I tried to prevent anyone from moving the prop backwards and you can't = imagine how often that happens. Hope that helps. I'm certain the cooling and lubrication from a wet system is part of the = reason they last so much longer. Cooling is probably the prime = requirement in a dry pump. Paul Spruce Creek On 2012-01-23, at 7:50 AM, Charles Brown wrote: > My experience with two wet vac pumps on a C-310 is that they never = failed. But they're rather large and heavy? as I recall. >=20 >=20 > On Jan 20, 2012, at 1:36 PM, thomas williams wrote: >=20 > a wet vacuum pump is VERY reliable compared to the dry pumps.=20 >=20 >=20 --Apple-Mail-15--661590860 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii In a = past life I went through a lot of dry pumps on the twin Cessna. We = did a lot of testing and found some easy ways to extend life. To = test, we turned a pump with a motor in the shop to see the temperatures. = The pump without airflow will get VERY hot and needs external = airflow. Once we ducted airflow with those addon plastic housings, = life was extended on the airframe. Also, we disassembled worn = pumps and found the carbon blades worn at the edges and getting thin. = Turning the pump backwards broke some of those blades. This = means that if you have someone turning your prop backwards on a worn = pump, it might lead to premature failure. I tried to prevent = anyone from moving the prop backwards and you can't imagine how often = that happens. Hope that helps.

I'm certain the = cooling and lubrication from a wet system is part of the reason they = last so much longer. Cooling is probably the prime requirement in = a dry pump.

Paul

Spruce = Creek

On 2012-01-23, at 7:50 AM, Charles Brown = wrote:

My experience with = two wet vac pumps on a C-310 is that they never failed. But = they're rather large and heavy? as I = recall.

On Jan 20, 2012, at 1:36 PM, = thomas williams wrote:

a wet vacuum pump is VERY reliable compared = to the dry pumps. =

=

= --Apple-Mail-15--661590860--