Mailing List flyrotary@lancaironline.net Message #46104
From: James Maher <delta11xd@att.net>
Subject: Re: [FlyRotary] Re: Initial Tuning - Today
Date: Mon, 11 May 2009 10:23:36 -0700 (PDT)
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Mike,
If you can not get the engine to idle below 1500 RPM with the throttle closed either or both of the following conditions could be the cause:
1. Manifold leak - if this is the case it should be found and fixed before any tuning is continued. Check all hoses and fittings on the intake manifold and throttle body. Check that the throttle is closing all the way. It may need adjustment.
2. Idle setting on throttle body not properly set. If the throttle body has a idle speed setting
screw (allows air after the throttle plate) try to turn it to reduce the idle.
Again 1500 RPM is okay when the engine is cold but once it warms up 850 RPM should be easily achievable.
 
Jim

--- On Mon, 5/11/09, Mike Fontenot <mikef@apexconsultingservices.com> wrote:
From: Mike Fontenot <mikef@apexconsultingservices.com>
Subject: [FlyRotary] Re: Initial Tuning - Today
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Date: Monday, May 11, 2009, 10:50 AM

Tracy (and other),

First, continued thanks for the feedback. Like Jim said, "You are making progress".  That is very true, I am so far ahead of where I was in August 2007, when trying to run this engine and the original combination of igniters/coils burned out at 3300 RPM. I have a much better electrical system (that I know the details of), control of all the critical circuits, and the engine RUNS! Good things will come.

Tracy, good advice to get on the same page with terminology. I will start with the MIXTURE INDICATOR, rather than a shotgun approach.



1. EM2 Mixture Indicator (MI) - lets sort this one out, I'll try to explain how I understand the MI, and hopefully we can come to a common ground. My notes on tuning keep coming back to the general goal of: "Mixture Knob at 1200 with Mixture Indicator reading 1 BAR for the engine throttle settings, except for Idle where you want 60% or 1+ bars".

My understanding is that the MI on the EM2 Standard Display Page 1 is:

A. MI is right above the voltage reading (Yes I have EGT connected, now I know what those other 4 bars are to the right).
B. MI is 2 BARS HIGH TOTAL. So when I say "50%"  I mean "1 BAR". If you define the EM2 display as having 4 LINES, and count
   from the top to bottom, Line 1, 2, 3, 4.  The MI is at lines 2 and 3.
C. My understanding is that 'stoichoimetric' is at 1 BAR
D. My understanding is that if the MI is below 1 BAR then that indicates LEAN, and visa versa, above 1 BAR indicates RICH.
E. My understanding for tuning goals, is that when the MIXTURE KNOB is at 1200
   1. Low MAP/RPM  - my goal is to have the MI reading at 1+ BAR, or around 60% because a little RICH is better at LOW RPM.
   2. Medium to high MAP/RPM - goal is to have the MI at 1 BAR (or 50%)
   3. High MAP/RPM - goal is to have MI around 1 BAR (or 50%). I want to avoid running too lean (below 1 BAR / 50%) to
      prevent burning vavles, etc.
F. My understanding is that using the EM2 Table View or Track View, the MI is at the far right and it is a total of 2 BARS
   HIGH (again Lines 2 & 3). So the corresponding statements about 1 BAR/50% hold here as well.

Tracy you wrote: >>2 bars is less than 20% of full scale.  How can it DROP to 30% from 2 bars?   What is your definition of 2 bars?   We have an obvious problem with terminology here.<<

This has me completely confused, obviously.

2. I will work on the electrical/alternator system as a priority. I think I know where the problem is, should not be hard to fix (I hope).

3. Jim: You said I should be able to idle down to 850 RPM. At my lowest throttle setting, when I start the engine the lowest RPM I've ever seen on the EM2 is around 1500 RPM. I can't drop it any lower than that, the throttle level just does
not go any further down. And I am letting it warm up before starting the tuning. I gotta tell you it is a joy to just sit there and listen to it run smoothly.

I'll stop here. Thanks,

Mike

PS. is there a way to simply 'REPLY TO' a posting in the flyrotary list, from that listing page ( http://mail.lancaironline.net:81/lists/flyrotary/List.html )?


================================
Mike Fontenot
Apex Consulting & Services LLC
Lakewood, Colorado
303 / 731-6645
mikef AT apexconsultingservices DOT com
================================
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