Received-SPF: none
 receiver=logan.com; client-ip=98.139.52.217; envelope-from=echristley@att.net
Message-ID: <5048CF62.8080509@att.net>
Date: Thu, 06 Sep 2012 12:29:22 -0400
From: Ernest Chrisltey <echristley@att.net>
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:15.0) Gecko/20120824 Thunderbird/15.0
MIME-Version: 1.0
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Single lever control
References: <list-5747400@logan.com>
In-Reply-To: <list-5747400@logan.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

A)  "near" is a weasel word.  If I get too close to cutoff lean, the 
engine will surge.  I've had to richen it up several times to keep it 
running smooth.  In normal operation, there should tuned to run smoothly 
at idle.

B) The normal operating range of the engine makes a diagonal path across 
the VE table.  To the right is higher RPM.  Going up is increasing 
throttle.  For a given throttle setting, there is a particular RPM that 
the engine should attain.  If it drops to the left (engine slows down), 
I have the table set to enrichen the mixture.  If it revs, the mixture 
goes even leaner.  The result is that there is a sort of ridge that the 
engine wants to ride along.  I'll probably need to get a screen shot of 
the VE table for this to make sense.


On 09/06/2012 10:34 AM, Bill Bradburry wrote:
> Earnest,
>
> If you were in the pattern and reduced power to the point where you were at
> half throttle or below and the mixture then went to "near cutoff lean" it
> seems you would be in danger of the engine stopping.  That might not be a
> desirable thing when you are that low to the ground even if you were in a
> pattern...??
>
> Bill B
>
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
> Behalf Of Ernest Chrisltey
> Sent: Thursday, September 06, 2012 10:19 AM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Single lever control
>
> This is what I was referring to in my previous email.  Throttle is
> graphed against RPM in both.  On the left, data points are colored based
> on coolant temps at the time the data point was captured.  The right
> graph uses AFR to set the color.
>
> The one on the left has the points colored according to coolant temp at
> the time the data point was collected. This graph tells me that a cold
> engine will make more power.
>
> The right graph has the points colored according to AFR, and is more
> interesting. My throttle plate is fully open at about 50% travel of the
> control lever.  My goal is to keep the mixture near cutoff lean until
> after the throttle plate is wide open. Until WOTP (wide open throttle
> plate) power increases from increasing the amount of intake charge.
> After that, pushing the lever forward increases power by enrichening the
> mixture.  I transition from changing the amount of mixture, to changing
> the makeup of it.   I would like a solid diagonal line, correlating
> throttle and RPM.  The graph shows me that I reach best power mixture to
> quickly.  I need to shift my target AFR a bit so that the lines flatten
> out with only 5% to 10% of lever travel left;  however, for the most
> part I've achieved the goal of having RPM directly correlated with
> throttle position.
>
>
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html
>