Return-Path: Received: from mail.viclink.com ([66.129.220.6] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3082972 for flyrotary@lancaironline.net; Wed, 17 Mar 2004 11:08:43 -0500 Received: from mail.viclink.com (localhost [127.0.0.1]) by mail.viclink.com (8.11.7/8.11.7) with ESMTP id i2HG8fN31952 for ; Wed, 17 Mar 2004 08:08:41 -0800 (PST) From: "Perry Mick" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: H.P. Fuel Pumps Date: Wed, 17 Mar 2004 08:08:41 -0800 Message-Id: <20040317160805.M67484@mail.viclink.com> In-Reply-To: References: X-Mailer: Open WebMail 1.90 20030226 X-OriginatingIP: 205.175.225.22 (pjmick) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 X-RAVMilter-Version: 8.4.3(snapshot 20030217) (mail.viclink.com) Yes, they are in-the-tank pumps. I have both in my sump tank. On Wed, 17 Mar 2004 09:56:06 -0500, Joseph M Berki wrote > Perry, > Are the Mazda pumps submersible? Would like to mount them > in the sump. > > Joe Berki > > At 06:42 AM 3/17/2004 -0800, you (Perry Mick) wrote: > >Al Gietzen wrote: > >> > >>Perry wrote: > >> > >> > >> > >>If you are flying and running only one h.p. fuel pump, and that pump > >>fails, the engine will become silent only milliseconds later! > >> > >> > >> > >>This is interesting. As my circuit diagram is currently configured, I > >>have a pressure switch in the fuel system which automatically turns on > >>the backup pump if the pressure drops below about 30 psi. (don t remember > >>now the exact setting on the pressure switch). Do you suppose that this > >>wouldn t react fast enough to keep the engine running? > >> > >> > >> > >> There is a manual bypass so I can turn the pump on if I want. The > >> idea was to turn on both pumps for takeoff, but at other times the > >> backup would automatically kick in to keep the engine from stopping if > >> the primary pump stopped; thereby avoiding rapid heart rates on the part > >> of pilot and passengers. > >> > >> > >> > >>Al > >That's an excellent idea Al. Probably the best solution. The engine > >stutters and dies as pressure drops below 20 psi. > > > >I just run both pumps all the time. (I get nervous if I turn one off, even > >at altitude). I can tell if one has failed because the pressure is > >slightly lower with only one pump on. Those Mazda pumps are extremely > >reliable. I use two junkyard pumps that probably had 100k+ miles in cars > >previously. No failures yet. I've also owned three 2nd gens with probably > >200kmiles accumulated between them and no failures yet. > >-- > >Perry Mick > >http://www.ductedfan.com