Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Wed, 22 Oct 2003 00:19:45 -0400 Message-ID: X-Original-Return-Path: Received: from omr-m11.mx.aol.com ([64.12.138.23] verified) by logan.com (CommuniGate Pro SMTP 4.1.5) with ESMTP id 2646001 for lml@lancaironline.net; Tue, 21 Oct 2003 20:34:00 -0400 Received: from Sky2high@aol.com by imo-m11.mx.aol.com (mail_out_v36_r1.1.) id q.1eb.11b6e6d3 (16781) for ; Tue, 21 Oct 2003 20:33:54 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <1eb.11b6e6d3.2cc72a72@aol.com> X-Original-Date: Tue, 21 Oct 2003 20:33:54 EDT Subject: Re: [LML] Re: Horsepower Calculation X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1066782834" X-Mailer: 9.0 for Windows sub 1100 -------------------------------1066782834 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 10/21/2003 4:19:45 PM Central Daylight Time, Epijk@aol.com writes: If you doubt that, just examine the equations and curves which Lycoming publishes to determine HP from known operating conditions. Jack, I did and they are virtually useless since I can't hold a ruler steady in turbulence. Plus, I will never understand just how the chart examples are worth anything because of the limiting caveats. Especially things like abs dry MAP, pressure altitude, standard temperature, certain compression ratio, no ram air, certain throttle body, state of engine, old fashioned oil, regular plugs, ordinary mags, certain injector size, ............. It doesn't even take into account true air temperature adjusted for compressability. I have never been able to match the known operating conditions in my "experimental" airplane. I don't care about exact calcs because nobody can tell me what horsepower I am generating without a "dyno". Of course, that dyno can't simulate flight conditions very well. Oh, you can try with SFC, etc, but this is no better than these other approximations (or thumb rules, if you wish). Just look at the 75% power entries in most POHs and see if the formula is close enough. Scott Krueger Sky2high@aol.com II-P N92EX IO320 Aurora, IL (KARR) -------------------------------1066782834 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 10/21/2003 4:19:45 PM Central Daylight Time, Epijk@a= ol.com writes:
If you doubt that, just examine the e= quations and curves which Lycoming publishes to determine HP from known oper= ating conditions.
Jack,
 
I did and they are virtually useless since I can't hold a ruler steady=20= in turbulence.  Plus, I will never understand just how the chart exampl= es are worth anything because of the limiting caveats.  Especially thin= gs like abs dry MAP, pressure altitude, standard temperature, certain c= ompression ratio, no ram air, certain throttle body, state of engine, old fa= shioned oil, regular plugs, ordinary mags, certain injector size, ..........= ... It doesn't even take into account true air temperature adjusted for= compressability.  I have never been able to match the known operating=20= conditions in my "experimental" airplane.
 
I don't care about exact calcs because nobody can tell me what horsepow= er I am generating without a "dyno".  Of course, that dyno can't simula= te flight conditions very well.  Oh, you can try with SFC, etc, but thi= s is no better than these other approximations (or thumb rules, if you wish)= .
 
Just look at the 75% power entries in most POHs and see if the formula=20= is close enough.
 
 
Scott Krueger
Sky2high@aol.com
II-P N92EX IO320 Aurora, IL (KARR)
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