Ah, thanks, Bill that helps. Ignore
my long winded explanation of previous e mail
Normally you would expect to see a manifold pressure value associated with
the bin address you selected on your EM – however, at least for address 0
– 31 – there is NO manifold pressure pointer associated – the
pointer is based solely on engine RPM. That MIGHT be why there is no
manifold pressure showing for the first 31 bins. I forget but I think the
bins 32-64 also are in some way RPM based if below a certain manifold pressure.
OR there is the possibility that the
EM has a problem.
ED
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bill Bradburry
Sent: Thursday, October 29, 2009
12:36 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: MCT
values in the 0-63 area of the EC-2
Data from the editing area of the EM-2 (the top two lines) when on the
MAP table screen.
Address Mixture correction Manifold
Pressure (actually first item on second line on the screen.)
0
-127
0
1
-127
0
shouldn’t these be manifold pressure or
2
+0
0
RPMs???
3
+0
0
4
+0
0
5
+0
0
6
+0
0
Etc…. thru address
63 Outer Space!?
64
+0
10.0
65
+0
10.5
66
+0
11.0
67
+0
11.5
Etc….thru address 127 continues in
.5 increments
Bill B
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Tracy Crook
Sent: Wednesday, October 28, 2009
11:57 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: MCT
values in the 0-63 area of the EC-2
Zero manifold
pressure? You could only have that if you were in outer space.
Obviously there is a misunderstanding here but I don't know on which end it is.
Let me try this: The two items associated with each address are these -
Address is associated with a particular manifold pressure (or rpm if less than 2500
AND less than the threshold pressure which is adjustable, not fixed at
13"). The other item is the DATA in that address which is the
correction factor applied at the manifold pressure (or rpm) associated with
that address. Neither of these 2 items will look remotely like the
numerical value of the actual manifold pressure. For instance, the
bottom of the mid-range rpm table (address 32) represents a manifold pressure
of about 8" Hg which is about the minimum that any engine will run at
under normal conditions.
Tracy
On Wed, Oct 28, 2009 at 11:39 PM, Bill Bradburry <bbradburry@bellsouth.net> wrote:
Tracy,
I think I
didn’t explain what I am seeing properly.
The addresses 0-63
should have associated with them two items. (I think)
The manifold
pressure that is associated with each address and the mixture correction that
is associated with that address and manifold pressure.
My table for
addresses 0-63 ALL have a manifold pressure of ZERO associated with them.
The mixture correction for each address varies, mostly zero, but not all.
It is the manifold
pressures that are all zero! Shouldn’t they have either manifold
pressures or perhaps RPMs listed??
On the addresses
64-127, the manifold pressures start at 10.0 and increase by .5 with each
additional address. Not so with the earlier addresses. I think this
is not correct, but I don’t think there is any way that I can affect the
manifold pressure indications.
Since the EC-2 can
flip back and forth between the high and low addresses at the same manifold
pressures but different rpms, several folks have reported having to ensure that
the corrections were similar at the two locations. I intended to verify
that they were similar, but since I don’t have the manifold pressures in
the table at the low addresses, I don’t know how I would compare
them. But more than that, I don’t understand how the EC-2 could
know what manifold pressure the lower address corresponds to and therefore which
correction it should apply.
Perhaps it only
looks for +/- 13 inches to go to addresses above or below 31? But then,
wouldn’t it need an RPM in each address to determine the correction???
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]
On Behalf Of Tracy Crook
Sent: Wednesday, October 28, 2009
11:09 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: MCT
values in the 0-63 area of the EC-2
The default values
in the table are supposed to be all zeros. There is a conceptual
misunderstanding about these values in your question. It is not the Data
that corresponds to the manifold pressure, it is the address. The data is
a correction value for the corresponding manifold pressure. The values
can be from -127 to + 127 with negative values causing the mixture to be
adjusted leaner and positive values richer.
Does that help?
Tracy
On Wed, Oct 28,
2009 at 6:35 PM, Bill Bradburry <bbradburry@bellsouth.net> wrote:
Tracy is back! What
about this question, Tracy?
The below from a
previous email…
Now I have more
questions. I went over and copied down the information in my MAP table
today. I was surprised to learn that the manifold pressures for all
addresses from 0 to 63 were set to Zero. I expected to find actual
manifold pressures in there. Starting with addresses 64 through 127 the
manifold pressures increase from 10.0 at address 64 in 0.5 inch increments all
the way to 41.8 inches at address 127. My engine is naturally aspirated,
so the manifold pressures above about 30 or 31 will never be used. I
understand that the 0 to 31 addresses are used when the RPM is below 2500 and
the manifold pressure is below 13 inches, and that the addresses from 32 to 63
are used when the RPM is between 2500 and 3800 and the manifold pressure is
above 13 inches. But I still don’t understand how the controller
would know which address to use with no manifold pressures entered in the
table. Tracy
is this is OK? Will these pressures be added when the engine is ran??
Bill B
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