Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Tue, 01 Mar 2005 12:14:01 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m16.mx.aol.com ([64.12.138.206] verified) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 764661 for lml@lancaironline.net; Tue, 01 Mar 2005 11:50:34 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.206; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m16.mx.aol.com (mail_out_v37_r3.8.) id q.145.40919eed (16633) for ; Tue, 1 Mar 2005 11:49:44 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <145.40919eed.2f55f727@aol.com> X-Original-Date: Tue, 1 Mar 2005 11:49:43 EST Subject: Taxiing Matters - Not Taxing, Taxiing! X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1109695783" X-Mailer: 9.0 Security Edition for Windows sub 5000 -------------------------------1109695783 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Let's define "taxiing" as any time your engine is running below 1500 RPM. Why is this useful? If your piston engine airplane is equipped with an oil pressure regulated "Hobbs" (counts time when the engine is running) and a tachometer that also records the time the engine is operating above 1500 RPM, you can calculate taxi time as a percentage of engine operation time. You can then figure out if it is worth the effort to pay attention during this phase of operation. If you fly a C172, with a slow cruise speed (relative to the canonical Lancair 320 speed), a very small percentage of engine time is spent in taxi since it takes so long to get anywhere. On the other hand, a very high cruise speed Lancair spends a large percentage of chronological engine time in taxi since so little time is spent in traveling from airport to airport. For me, approximately 15% of engine operational time is spent below 1500 RPM ((Hobbs - Tach)/Hobbs). What's yours? Especially Legacy and IV-P people. To me, 15% to 20% makes it really worthwhile to operate the engine properly and, like many others, I aggressively lean during the taxi phase - generally, the big pull to a known visual position of the mixture knob, to be fine tuned when time is available. I do this shortly after engine start and as I pull off the runway after landing (assuming I am able to leave the runway under power). If it matters, the placard on the mixture knob (Push Mixture Rich) has been thumbed to an almost unreadable state. I may have to placard that placard as inoperable. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Fair and Balanced Opinions at No Charge! Metaphysical Monologues taken at your own Risk. -------------------------------1109695783 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Let's define "taxiing" as any time your engine is running below 1500=20 RPM. Why is this useful? If your piston engine airplane is equip= ped=20 with an oil pressure regulated "Hobbs" (counts time when the engine is runni= ng)=20 and a tachometer that also records the time the engine is operating abo= ve=20 1500 RPM, you can calculate taxi time as a percentage of engine operation=20 time. You can then figure out if it is worth the effort to pay attenti= on=20 during this phase of operation.

If you fly a C172, with a slow cruise speed (relative to the canonical=20 Lancair 320 speed), a very small percentage of engine time is spent in=20 taxi since it takes so long to get anywhere.&n= bsp;=20 On the other hand, a very high cruise speed Lancair spends a large percentag= e of=20 chronological engine time in taxi since so little time is spent in traveling= =20 from airport to airport.

For me, approximately 15% of engine operational time is spent below 150= 0=20 RPM ((Hobbs - Tach)/Hobbs). What's yours? Especially Legacy and IV-P=20 people.

To me, 15% to 20% makes it really worthwhile to operate the engine= =20 properly and, like many others, I aggressively lean during the taxi pha= se -=20 generally, the big pull to a known visual position of the mixture knob, to b= e=20 fine tuned when time is available. I do this shortly after engine star= t=20 and as I pull off the runway after landing (assuming I am able to leave the=20 runway under power). If it matters, the placard on the mixture knob (P= ush=20 Mixture Rich) has been thumbed to an almost unreadable=20 state. I may have to placard that placard as inoperable.=20

Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Fai= r=20 and Balanced Opinions at No Charge!
Metaphysical Monologues taken at your= own=20 Risk.

-------------------------------1109695783--