REFLECTOR: Fuel Consumption Performance more data

Scott Derrick scott at tnstaafl.net
Tue Sep 8 17:28:53 CDT 2009


Sorry Brent I see you included that in your original message.

Scott

Brent Bourgeois wrote:
> 2 way average ground speed with GPS
>
> --- On *Tue, 9/8/09, Scott Derrick /<scott at tnstaafl.net>/* wrote:
>
>
>     From: Scott Derrick <scott at tnstaafl.net>
>     Subject: Re: REFLECTOR: Fuel Consumption Performance more data
>     To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>     Date: Tuesday, September 8, 2009, 8:31 AM
>
>     you didn't say if that 190mph was TAS,  IAS, ground speed and how you
>     measured it?
>
>     Brent Bourgeois wrote:
>     > These are the numbers from 9-3-09 for my Std RG  IO-360 200Hp
>     > Speed is a 2 way average from the gps.
>     > 
>     > 9500 ALT
>     > 2580/20.2
>     > 40 deg LOP
>     > 190 MPH
>     > 9 GPH
>     > 55 OAT
>     > 
>     > Brent
>     > N61VB
>     > New Orleans La
>     >
>     >
>     > --- On *Fri, 8/28/09, John Tvedte /<johnt at comp-sol.com
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=johnt@comp-sol.com>>/*
>     wrote:
>     >
>     >
>     >     From: John Tvedte <johnt at comp-sol.com
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=johnt@comp-sol.com>>
>     >     Subject: Re: REFLECTOR: Fuel Consumption Performance
>     >     To: "Velocity Aircraft Owners and Builders list"
>     <reflector at tvbf.org
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector@tvbf.org>>
>     >     Date: Friday, August 28, 2009, 11:29 PM
>     >
>     >     Terry,
>     >
>     >     I think Scott is saying... as you lean, the first cylinder
>     to peak
>     >     is the leanest - the last to peak is the richest... if cruising
>     >     ROP, you lean by the leanest cylinder (first to peak), but if
>     >     cruising LOP, you lean by the richest cylinder (last to peak) -
>     >     because you are on the other side of the Red Box.
>     >
>     >     www.eaa42.org/misc/gregs_show.ppt
>     >
>     >     Note, I do not claim to have any practical experience.
>     >
>     >     John
>     >
>     >     ________________________________________
>     >     From: reflector-bounces at tvbf.org
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>
>     > 
>        <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>
>     >     [reflector-bounces at tvbf.org
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>
>     > 
>        <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>]
>     >     On Behalf Of Terry Miles [terrence_miles at hotmail.com
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=terrence_miles@hotmail.com>
>     > 
>        <http://us.mc513.mail.yahoo.com/mc/compose?to=terrence_miles@hotmail.com>]
>     >     Sent: Friday, August 28, 2009 11:31 AM
>     >     To: 'Velocity Aircraft Owners and Builders list'
>     >     Subject: Re: REFLECTOR: Fuel Consumption Performance
>     >
>     >     Well I appreciate your patience.  I did read the below articles,
>     >     and several
>     >     books now on related engine operations and mixture settings
>     and we
>     >     are in
>     >     full agreement on the concept.  I am not running ROP.  I am
>     running 50
>     >     degrees LOP.  The question between us is which cylinder
>     should be the
>     >     reference cylinder.  My choice in this is that I will use the
>     >     first cylinder
>     >     to peak.
>     >     Thanks again.
>     >     Terry
>     >
>     >     -----Original Message-----
>     >     From: reflector-bounces at tvbf.org
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>
>     > 
>        <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>
>     >     [mailto:reflector-bounces at tvbf.org
>     <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>
>     > 
>        <http://us.mc513.mail.yahoo.com/mc/compose?to=reflector-bounces@tvbf.org>]
>     >     On
>     >     Behalf Of Scott Derrick
>     >     Sent: Thursday, August 27, 2009 21:01
>     >     To: Velocity Aircraft Owners and Builders list
>     >     Subject: Re: REFLECTOR: Fuel Consumption Performance
>     >
>     >     Terry,
>     >
>     >     Below is my reply of a month ago when you indicated you were
>     >     leaning to 50
>     >     LOP on the first cylinder to peak.  All the rest being richer.
>     >     Which as I
>     >     stated a month ago is BAD!
>     >
>     >     Maybe I misunderstood and you are now running ROP?  Leaning
>     until
>     >     the first
>     >     cylinder reaches peak, and then enriching it until it is 50 ROP?
>     >     That would be the old school acceptable  method.  If you
>     decide to
>     >     read the
>     >     articles below, you will read that  GAMI recommends 75 ROP
>     because
>     >     50 ROP
>     >     may be stressful to some engines  at high power settings and low
>     >     altitude.
>     >
>     >     But, since you were running at 10K or above you can run at
>     any mixture
>     >     setting and be fine, as far as detonation is concerned
>     because the
>     >     engine
>     >     cannot produce more than 75% power at full throttle.
>     >
>     >     I once again recommend the articles below by  John Deacon
>     about how to
>     >     safely  operate these big bore aircraft engines.  They are
>     >     expensive and
>     >     easy harm.
>     >
>     >     Scott
>     >
>     >
>     >     **********************************************************
>     >
>     >     Terry,
>     >
>     >     running the first cylinder LOP can put some of the richer
>     >     cylinders right in
>     >     the BAD zone. Thats well... bad!  Thats why you always lean
>     to the
>     >     last
>     >     cylinder when running LOP.  Thats also why you lean to the first
>     >     cylinder
>     >     when running ROP, so all the other cylinders are rich of
>     that point.
>     >
>     >     you said
>     >
>     >     "I was afraid my coolest cyl could be 150 LOP before the
>     last cly
>     >     peaked and
>     >     that I could burn that exhaust valve."
>     >
>     >
>     >     Thats exactly backwards. Once a cylinder reaches peak EGT
>     and goes
>     >     on the
>     >     LOP side it will run cooler and cooler the leaner you run
>     it. The
>     >     absoluter
>     >     worst mixture is about 25-50 degrees ROP in terms of detonation
>     >     and the
>     >     timing of peak power pulses.  If your coolest cylinder was
>     running
>     >     at 150
>     >     degrees leaner than the last cylinder to reach 75 LOP it would
>     >     probably not
>     >     be firing due to the too lean mixture.
>     >
>     >     How to operate your engine is a complex topic.  Here is a
>     great set of
>     >     articles by John Deacon, I consider a must for any recip
>     operator,
>     >     whether
>     >     you run LOP or ROP.
>     >
>     >     part 1
>     >     http://www.avweb.com/news/pelican/182179-1.html
>     >     part 2
>     >     http://www.avweb.com/news/pelican/182176-1.html
>     >     part 3
>     >     http://www.avweb.com/news/pelican/182583-1.html
>     >     part 4
>     >     http://www.avweb.com/news/pelican/183094-1.html
>     >
>     >
>     >     Here's GAMI's lean test,  a great thing for anybody to do,
>     to see how
>     >     balanced their injectors are.
>     >
>     >     http://www.gami.com/gamijectors/leantest.php
>     >
>     >
>     >     Scott
>     >
>     >
>     >
>     >     >
>     >
>     >
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>     >
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