-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bill Bradburry
Sent: Friday, October
16, 2009 3:26 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Stoich
A/F Ratio?? : [FlyRotary] Re: where's the missing power?
Steve,
The values that are 0 are in the column for manifold
pressure. The column for the MAP correction has numbers like you are
describing.
Wait a minute. I’m
confused. I’ve been talking about the correction values in the bins
– I thought those were zeros you were concerned with. There is a
certain value of MAP that corresponds to each rpm. If you look at this in track
mode with the engine running it may make a lot more sense.
Meanwhile; I better get out of this
discussion; we don’t seem to be on the same page.
Al
Plus numbers for above the mid point and negative
numbers for below the mid point. But without manifold pressure or RPM
numbers, I don’t understand how the computer can figure out which bin to
select. With all them 0, it would be some kind of random unless the
program has a way of attaching a bin to a bin.
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of sboese
Sent: Friday, October 16, 2009
7:16 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Stoich
A/F Ratio?? : [FlyRotary] Re: where's the missing power?
Ed & Bill,
If I understand correctly
from discussion with Tracy, the default value of 128 for a MAP table value is
what you would read directly from the data stream. The 128 is reported as
zero on the EM3 with positive values indicating enrichment and negative values indicating
leaning. Values of zero on the EM3 are values which have not been changed
from the default.
Steve
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Ed Anderson
Sent: Friday, October 16, 2009
4:49 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Stoich
A/F Ratio?? : [FlyRotary] Re: where's the missing power?
Ok, I
understand now Bill. I think Al answered your question on how far from
14.7:1 to 9:1 on his controller of his 3 rotor – That’s the only
information I am aware of about how much twisting of the manual mixture control
it may take. I can simply state that with the mixture Knob at 3:00 its
too much fuel for my N/A turbo block – so I would say Al’s
information sounds reasonable to me.
Unless
Tracy has really changed things with the EC3, there are NO manifold pressure
values in any bins (columns of the table) – the manifold pressure (when
used) is converted into a “bin” pointer which points to the
appropriate bin (numbered from 0 – 128) for that corresponding manifold
pressure). That “bin” selected by the manifold pressure value
of the engine then contains a fuel factor value represented by the value
(height) of the bar in that bin. I believe Tracy’s default value is
128 which theoretically would give a 14.7:1 air/fuel ratio. Going above
that value enriches the mixture and below leans it.
IF
there are zeros for the values of any of the bins then that says there is
no Map correction Table (MCT) correction factor used for that bin. . So
if the values of zero are valid, I would assume that for those regions
the fuel needed must be derived solely from some other parameter – like
RPM with the manifold pressure value only acting as a switch (above below 13Hg
for example)
But, if
that is indeed the case then I’m still a bit surprised there are no MCT
values for rpm.
There is
the possibility that somehow the MCT values for those bins were set to zero
accidentally, but as you so rightly surmised, only Tracy can answer the
question you have.
Ed