REFLECTOR: Fuel Consumption Performance more data
Scott Derrick
scott at tnstaafl.net
Tue Sep 8 08:31:57 CDT 2009
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>/* wrote:
>
>
> From: John Tvedte <johnt at comp-sol.com>
> Subject: Re: REFLECTOR: Fuel Consumption Performance
> To: "Velocity Aircraft Owners and Builders list" <reflector at 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>
> [reflector-bounces at 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>]
> 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>
> [mailto:reflector-bounces at 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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