REFLECTOR: Fuel Consumption Performance

[Scott Derrick]

Terry,

I'm all astonishment! 

Good luck, please don't carry passengers.

Scott

Terry Miles wrote:
> 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 [mailto:reflector-bounces at 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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