What I found on my 20B, on the dyno; was
the max power was 125-150 rich of peak EGT. That put the EGTs right
around 1600F on the 9.0 : 1 rotors at 6000 rpm. At 5000 rpm the EGTs were
about 1550F.
On my EC2, about 2:30 position gives me max
power; 12:00 position gives me about 50F lean of peak; so I’d say roughly
2 clock positions to go from stochiometric to max power.
YMMV,
Al
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bill Bradburry
Sent: Friday, October 16, 2009
4:57 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Stoich
A/F Ratio?? : [FlyRotary] Re: where's the missing power?
Good point, Ed.
How much change does the mixture knob on the EC-2/3
allow? Say for instance, if Mike was at 14.7 at full throttle with the
mixture knob at the center position, how far would he have to turn the knob to
the right to achieve 12.65 AFR? I ask this because the A/F gage will not
read that mixture. It will be topped out well before that mixture ratio
occurs. How do you determine best power mixture?
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Ed Anderson
Sent: Friday, October 16, 2009
8:35 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Stoich A/F
Ratio?? : [FlyRotary] Re: where's the missing power?
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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