Return-Path: Received: from [65.33.162.131] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 4.1.8) with HTTP id 2752168 for flyrotary@lancaironline.net; Wed, 19 Nov 2003 19:09:55 -0500 From: "Marvin Kaye" Subject: Re: [FlyRotary] Re: gauges To: "Rotary motors in aircraft" X-Mailer: CommuniGate Pro WebUser Interface v.4.1.8 Date: Wed, 19 Nov 2003 19:09:55 -0500 Message-ID: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Posted for "John Slade" : > That gauge shows the entire range of deck pressures available, Thanks for the explaination, Marv. That helped me too. How about one more question - Theres a UMA MAP gauge in the Spruce catalog which is "altitude and temperature compensated". What does that mean? It adjusts for changing pressure as you climb? What good would that do? John Slade

Sorry, John, I don't have an answer for that one. The GRT EIS (and Chelton's EAU, same thing) instrument uses a separate black box to sense the manifold pressure. The box is mounted inside the cabin and there's a -3 hose that connects to a port on the intake manifold. Whatever pressure is present in the manifold is piped to the manifold pressure sensor box and the transducer circuitry inside turns that pressure into a signal that the instrument understands. A conventional analog MAP gauge is basically an altimeter with a different scale and no Kollsman window... the manifold pressure is piped to it directly, just like you pipe the static port to the altimeter. I don't get what this altitude and temp compensation is for or what it does... my understanding is that we are simply reading the manifold absolute pressure, thus the acronym "MAP". I'm sorry, but this one is beyond me.