Return-Path: Received: from imo25.mx.aol.com ([198.81.17.69]) by truman.olsusa.com (Post.Office MTA v3.5.1 release 219 ID# 0-52269U2500L250S0V35) with ESMTP id com for ; Tue, 12 Jan 1999 09:10:10 -0500 Received: from N295VV@aol.com by imo25.mx.aol.com (IMOv18.1) id 0CYCa15302 for ; Tue, 12 Jan 1999 09:11:24 -0500 (EST) From: N295VV@aol.com Message-ID: Date: Tue, 12 Jan 1999 09:11:24 EST To: lancair.list@olsusa.com Subject: Re: Vacuum Pumps X-Mailing-List: lancair.list@olsusa.com Mime-Version: 1.0 <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> From: N295VV@aol.com (n295 v v @aol.com) Probably the most important aspect of vacuum pump lifetime is what gets sucked into the rotating vanes. For this reason, pleated filters should be placed upstream at any point where the air is being scavaged by the pump. The weakest point of this filtration attempt is probably the cheap wrist-band foam filter that is used on the vacuum adjustment guage. There are some great space-age self-lubricating ceramic materials that could be used in place of the carbon vanes, and I would hope someday that we might see the advent of a pump that would last 10,000 hours. The darn things never fail in VFR--it is always marginal conditions or full IFR. David Jones