Return-Path: Received: from [65.33.163.242] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 4.3c1) with HTTP id 740694 for flyrotary@lancaironline.net; Tue, 15 Feb 2005 18:43:29 -0500 From: "Marvin Kaye" Subject: Re: [FlyRotary] Re: For Ernest Re: More on Header Tanks, Venting & Pressure Reg Position To: "Rotary motors in aircraft" X-Mailer: CommuniGate Pro WebUser Interface v.4.3c1 Date: Tue, 15 Feb 2005 18:43:29 -0500 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Posted for Ernest Christley : """ And third, I now see why the regulator is located so close to the injectors. 'Cause that is where the reference pressure is. If is moved further away you kill its response. """ I don't think that is correct. You're not interested in moving any volume of air through the MAP pressure hose to the MAP sensor, just transmitting the pressure. A very small ID hose is all that should be required, and its distance from the source (within reason, of course) should not have a lot of effect. While it may not be MAP pressure that's involved in my example, the principle is still the same... the AOA instrument that I've been selling at Oshkosh and Sun'n'Fun for the past 6 years uses two 1/16" ID urethane hoses to transmit the pressures from the top and bottom of the wing to the pressure transducers inside the system's black box that is located in the cockpit. The pressure ports on the wing are located at near the wing-tip, making the hose runs anywhere from 15-25 feet on a typical experimental aircraft, and the respose of the instrument to changes in AOA (changes in differential pressure between top and bottom of wing) are instantaneous. Given that the physics is basically the same, I can't see why a little distance between the manifold and the MAP sensing portion of the regulator should enter into the equation at all. Having the regulator at the far end of the fuel rail allows fresh fuel to continue to flow through the rail regardless of the fuel demand by the injectors, thus keeping the fuel cooler and less prone to vaporizing inside the rail. Its proximity to the intake manifold is simply a consequence of this type of installation. At least that's what I've grown to understand throughout this entire conversation.