Hi Mike,
I guess I’m missing something - If your
mixture monitor shows stoich at full throttle, then it’s not solely an
airflow problem – it appears to me that it’s the lack of sufficient
fuel. IF you are at stoich 14.7:1 A/F ratio then that means you have more oxygen
available in your system to support burning more fuel = more power. You
should be able to enrich the mixture particularly at full throttle (assuming
you are wanting full power at full throttle) to around 12.65:1 air/fuel ratio
for best power. I know you know all of this - that is why I am puzzled by your
statement that you feel it’s an airflow problem when on the surface with
the Stoich ratio it would appear it’s a lack of sufficient fuel.
Ed.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mike Wills
Sent: Thursday, October 15, 2009
11:22 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: where's
the missing power?
Sorry for my absence on a topic I started. My nephew
had a skateboarding accident last weekend and is in the hospital in a
chemically induced coma until his brain swelling is under control. And I
thought car powered airplanes were dangerous. Stay away from skateboards.
Tracy - My
mixture monitor shows stoich at full throttle. I suspect an airflow issue
rather than fuel.
Al - my vacuum gauge is located in the plenum directly
behind the throttle plates.
Lynn - I agree
that the TB inlet is horrible and needs a bell mouth. The inlet is also pretty
obstructed by the cowl which isnt visible in the pics I sent. I think I'll make
an attempt to clean this up some and see if it gets me anywhere. If not I'll
live with it for a while.
Kelly - always tough to determine if the problem is an
engine issue or if the load is simply too much for the engine to overcome. I'm
going to experiment with the shallow dive several have suggested and see what
happens.
----- Original Message -----
Sent: Tuesday, October
13, 2009 4:21 PM
Subject: [FlyRotary] Re: where's
the missing power?
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Al Gietzen
Sent: Tuesday, October 13, 2009
7:22 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: where's
the missing power?
I dont have a regular manifold
pressure gauge, just an industrial type vacuum gauge ( I really gotta get an MP
gauge). Anyway, the vacuum gauge was indicating 4" of vacuum.
Where are you measuring the 4”
vacuum? If it is near the ports it is no unusual; if it is out before the
runners; something is wrong.
Al
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