X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 12 Jul 2008 20:47:03 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d04.mx.aol.com ([205.188.157.36] verified) by logan.com (CommuniGate Pro SMTP 5.2.5) with ESMTP id 3023336 for lml@lancaironline.net; Sat, 12 Jul 2008 18:34:53 -0400 Received: from Sky2high@aol.com by imo-d04.mx.aol.com (mail_out_v38_r9.4.) id q.d06.36dc6cd2 (39329); Sat, 12 Jul 2008 18:34:46 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Sat, 12 Jul 2008 18:34:46 EDT Subject: Re: [LML] LIV & Legacy - Economy Cruising IO-550 X-Original-To: lml@lancaironline.net, fredmoreno@optusnet.com.au MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1215902086" X-Mailer: Unknown sub 34 X-Spam-Flag:NO -------------------------------1215902086 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Fred, Verrrry interrrresting! On a pleasure flight yesterday, I wanted to get a certain data point for LOP and ROP at reduced power. Here is what it looked like in the style you used. I was at 4400 MSL (6210 Dalt), 22.7" MAP, 2330 RPM (maybe 65% power????) in an auto pilot managed flight (similar to your 4K numbers). @50 LOP, 5.8 gph and 169 KTAS (3.43g/100nm). @100 ROP, 7.9 gph and 181 KTAS (4.36g/100nm). A 7% increase in speed cost a 27% increase in fuel consumption. Much like the ROP comparison you gave. Maybe I will go after more data points - but only on real trips as the costs are not worth getting "experimental" support for the truth as we know it (see emboldened, slanted and underlined text below). Grayhawk In a message dated 7/12/2008 4:13:00 P.M. Central Daylight Time, fredmoreno@optusnet.com.au writes: I took the best (least scatter, most consistent) sets of runs for my typical cruise conditions (8500 Feet, 55-65% power,50F lean of peak) and then compared to the Cessna/Columbia 350 performance tables from the pilots operating handbook that was once available at the Columbia web site. I found that if I multiplied the Columbia 350 speed by 1.27, I got a very good fit over the full speed range I have examined. I then plotted the modified Columbia figures and with an Excel spread sheet I generated tables and then curves for gallons/100 nautical miles as a measure of fuel economy. I argue that this provides the best measure of comparative operating costs, better than miles per gallon which distorts the presentation. Here are the results. ................. These curves support previous suggestions for economical flying: fly slower, fly higher, and fly lean of peak. ............... But the cost of cranking it up to 75% and running rich of peak is +20% in cost while gaining only about +6% in speed. Or, if you like, it costs 20% more to arrive 3.6 minutes sooner for each hour of flight. **************Get the scoop on last night's hottest shows and the live music scene in your area - Check out TourTracker.com! (http://www.tourtracker.com?NCID=aolmus00050000000112) -------------------------------1215902086 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Fred,
 
Verrrry interrrresting!  On a pleasure flight yesterday, I wanted=20= to=20 get a certain data point for LOP and ROP at reduced power.  Here is wha= t it=20 looked like in the style you used.
 
I was at 4400 MSL (6210 Dalt), 22.7" MAP, 2330 RPM (maybe 65% power????= ) in=20 an auto pilot managed flight (similar to your 4K numbers).  @50 LOP, 5.= 8=20 gph and 169 KTAS (3.43g/100nm).  @100 ROP, 7.9 gph and 181 KTAS=20 (4.36g/100nm).  A 7% increase in speed cost a 27% increase in fuel=20 consumption.  Much like the ROP comparison you gave. 
 
Maybe I will go after more data points - but only on real trips as= the=20 costs are not worth getting "experimental" support for the truth as we=20= know=20 it (see emboldened, slanted and underlined text below). 
 
Grayhawk
 
In a message dated 7/12/2008 4:13:00 P.M. Central Daylight Time,=20 fredmoreno@optusnet.com.au writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D3>

I took the best (least scatt= er,=20 most consistent) sets of runs for my typical cruise conditions (8500 Feet,= =20 55-65% power,50F lean of peak) and then compared to the Cessna/Columbia 35= 0=20 performance tables from the pilots operating handbook that was once availa= ble=20 at the Columbia web site.  I found that if I multiplied the=20 Columbia 350 speed by 1.27, I got a very good fit ove= r the=20 full speed range I have examined. 

I then plotted the modified=20 Columbia figures and with an Excel spread sheet I gen= erated=20 tables and then curves for gallons/100 nautical miles as a measure of fuel= =20 economy.  I argue that this provides the best measure of comparative=20 operating costs, better than miles per gallon which distorts the=20 presentation.  Here are the results.

.................

These curves su= pport=20 previous suggestions for economical flying: fly slower, fly higher, and fly=20= lean=20 of peak.

...............

<= SPAN=20 style=3D"FONT-SIZE: 12pt; FONT-FAMILY: Arial">But the cost of cranking it up= to=20 75% and running rich of peak is +20% in cost while gaining only about +6% in= =20 speed.  Or, if you like, it costs 20% more to arrive 3.6 minutes sooner= for=20 each hour of flight.




Get the scoop on last night's hottest shows and the live music sce= ne in your area - Check out TourTracker.com!
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