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With the zener diode and 620 ohm resister
to ground. I would not know how to wire it with two CAS’s. Best to ask Tracy if it’s worth
testing. Bobby
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of bktrub@aol.com
Sent: Wednesday, June 22, 2011
8:53 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: This has
got to stop
Thanks. That's one more item to be
checked and ruled out. So basically you are putting a 18-20 K resister in line
on the CAS circuit?
-----Original
Message-----
From: Bobby J. Hughes <bhughes@qnsi.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, Jun 22, 2011 8:13 pm
Subject: [FlyRotary] Re: This has got to stop
Dennis H and my self implemented an
external circuit that eliminated this very symptom. BUT our problems were with the Renesis CAS and older EC2
mods. The circuit limited the CAS voltage to around 8V-peak to peak. At high
rpm before the 18k-20k resister the EC2 would see 30V peak to peak and would
stumble. The CAS voltage goes up with rpm. Not likely this is your problem but
it might be worth testing if all other tests fail to identify the issue.
Dennis and I were able to trigger the event on the ground so safe testing was not an issue.
I am using the stock 13 BREW sensors- two
sensors and trigger wheel. I am using four chevy LS1 coils.
You made no mention of
the type of sensors and coils you are using.........Are you
using the 13BREW two sensor (pickups) and
trigger-wheel system with stock coils
or "GM" coils??...............
Kelly Troyer
"DYKE DELTA
JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo
Your symptoms are exactly what I fought
with for over a year with my 20B. The problem turned out to be the CAS.
I had thought it would be a big improvement to go with the Renesis type
CAS, so I had Tracy convert my EC-2 to work with
the crank mount CAS, and I added a trigger wheel and
bracket to the front of my engine. Depending on the sensor gap and the
phase of the moon, it would run great up to the upper 5000's, then it would
start mis-firing badly. No amount of tuning would correct the problem.
This may not be your exact scenario, but I hope it will help you
determine if it is ignition or fuel. My guess is ignition.
Oh, to fix my problem, I had Tracy convert my EC-2
back to work with the old "distributor" style CAS, reinstalled the
old CAS, and that corrected the probmel. It now runs great up to >
70000 rpm.
I'm going to ground my airplane until I
get to the bottom of this. I can tune it on the ground and it will run just
fine all the way from idle to full throttle. I get about 5300 rpm at full
throttle at 29 in hg. MP. I have 12 hours in the air so far but can't get past
this issue. Other than this, the plane is an absolute joy.
When I get off the ground, when I go
through around 5400 RPM, I start to get stumbling and engine roughness. At this
RPM I am about 18 inches MP. Just below this point, I am making about 50% power
and the engine will run smoothly.
I went to another airport and had a lot of
roughness on takeoff, but I am used to it and so continued on my way to my home
airport. When I got back I found out that someone at the other airport wanted
to report me to FSDO because he thought my engine was going to blow up, but he
didn't get my tail number.
So, I thought I had it sorted out before I
flew today, but it's back to the drawing board. I've tried both leaning and
enriching the mixture at all throttle settings, but to no avail. At and above
5400 rpm I start getting all sorts of roughness so I think that it has to be an
ignition issue. My injector wiring is separated from my coil wiring, but could
I be getting inductance between the different coil wiring?
I have a 93 13 BREW normally aspirated, 2.85
RWS redrive, EM2, EC2, 88x 74 CAtto Prop. This is getting to be really
frustrating. It's got to be something simple that I'm overlooking. I don't know
anyone with an ocilliscope, and have never used one.
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