Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Tue, 28 Dec 2004 16:15:09 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m19.mx.aol.com ([64.12.137.11] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 582166 for lml@lancaironline.net; Tue, 28 Dec 2004 11:53:31 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.11; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m19.mx.aol.com (mail_out_v37_r3.8.) id q.1ef.3206aedb (4410) for ; Tue, 28 Dec 2004 11:52:58 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <1ef.3206aedb.2f02e96a@aol.com> X-Original-Date: Tue, 28 Dec 2004 11:52:58 EST Subject: Re: [LML] Re: airspeed vs. power X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1104252778" X-Mailer: 9.0 Security Edition for Windows sub 5000 -------------------------------1104252778 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 12/28/2004 8:32:56 A.M. Central Standard Time, Walter@advancedpilot.com writes: Reducing MP 1" from WOT will not give proper FF change readings as the fuel enrichment feature causes a larger drop in FF than MP as the throttle is first retarded. This results in a a leaning effect and the mixture is not staying the same. The drop in FF as RPM is retarded is a much more accurate measure as the the change in the engine driven fuel pump allows the mixture to remain fairly constant. Walter, Within the limitations of our on board instrumentation, are you saying that the FF would not be within 10% of each other during this diagnostic (if everything was working as it should)? The last time I looked at my fuel pressure, as measured by a tee off the engine driven pump outlet, it did not change over a drop of 100 RPM and, in any event, remained well above the pressure necessary for the throttle body to correctly meter it to the spider. Of course, in both cases the Bendix throttle body venturis do see a slight drop in pressure as the airplane slows. I agree the mixture must change as there does seem to be a slight change in the EGTs (as measured by my "instrumentation"). More on MAP meters later! Scott Krueger AKA Grayhawk N92EX IO320 Aurora, IL (KARR) -------------------------------1104252778 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 12/28/2004 8:32:56 A.M. Central Standard Time,=20 Walter@advancedpilot.com writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Reducing=20 MP 1" from WOT will not give proper FF change readings as the
fuel=20 enrichment feature causes a larger drop in FF than MP as the
throttle=20= is=20 first retarded. This results in a a leaning effect and the
mixture is=20= not=20 staying the same. The drop in FF as RPM is retarded is
a much mo= re=20 accurate measure as the the change in the engine driven
fuel pump allo= ws=20 the mixture to remain fairly constant.

Walter,

Within the limitations of our on board instrumentation, are you saying=20= that=20 the FF would not be within 10% of each other during this diagnostic (if= =20 everything was working as it should)?

The last time I looked at my fuel pressure, as measured by a tee o= ff=20 the engine driven pump outlet, it did not change over a drop of 10= 0=20 RPM and, in any event, remained well above the pressure necessary for t= he=20 throttle body to correctly meter it to the spider. Of course, in=20= both=20 cases the Bendix throttle body venturis do see a slight drop in pressure as=20= the=20 airplane slows.

I agree the mixture must change as there does seem to be a slight chang= e in=20 the EGTs (as measured by my "instrumentation").