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----- Original Message -----
From: "John Slade" <sladerj@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, May 06, 2004 2:42 PM
Subject: [FlyRotary] Re: surging
> Turbo Rotary Cozy IV N96PM flew again this morning.
> I think this is a first! Nothing went wrong, and I didn't break anything.
> :D
>
> I flew for about 0.8hrs. Ambient was about 75. Coolant and oil never went
> above 180, and were down to 140 during decent, so cooling just doesn't
seem
> to be a problem.
>
> A write up (with pictures this time) is at
> http://canardaviation.com/cozy/chap29.htm#flight5
> for your enjoyment.
>
> I still have a rich mixture problem. Its starting much easier now, and
> running smooth, but still way too rich. Today I had the mixture knob
against
> the stop (lean) for the entire flight. Once I tried richening it a touch,
> and the engine faultered immediately. The mode 3 (on the ground)
adjustments
> dont seem to make any difference. I wonder if I need smaller injectors or
> lower fuel pressure (currently running about 45psi).
>
> Thoughts anyone?
> John Slade
>
>
John, did you by any chance copy down the part number (very small numbers on
the edge of the plastic part of the injector connector? I have had people
send me injectors stating they were one flow rate and type (low/high
impedance) and when I checked the number on the side, I knew they were a
different flow rate or type. Also, could you refresh my memory - I believe
you have the high impedance turbo II 550 cc/min injectors - is that correct?
The reason I am asking, is that I have found the rotary can take an enormous
amount of excess fuel (once you are above 3500-4000 rpm without faltering at
all. The only noticeable effect is my EGT goes down in temp. So I am a bit
surprised that enriching it with the mixture control even a bit causes it to
stumble.
However, I suppose that you could be close to the choke point at max lean
and the next little bit is all it takes to cause it to start faltering.
Something is not as it should be.
I run between 40 and 43 psi on fuel pressure. Your higher pressure might
make a difference at idle, but I seriously doubt that would be the sole
cause of a problem at higher rpms.
You didn't say, but what were some typical rpms and boost levels during the
flight?
Ed Anderson
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