Bobby,
I have not done any testing with a wideband O2 sensor. Unless the engine were operating right on a threshold of a large untuned injector pulse width change (staging is the only thing that comes to mind), it seems unlikely that the variation in O2 sensor would be associated with injector delay.
Within the limits that were tested, the EGT increased with increased exhaust back pressure due to partial blockage. The mixture was somewhat rich and no change in O2 sensor was seen. Lean mixtures were not investigated at that time.
Steve
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. Hughes
Sent: Sunday, March 20, 2011 7:46 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Forced Landing.
Steve,
Thanks for the offer. Actually I think it would be great if you could conduct a test. I had thought about a block off plate that could be pulled into place with a long wire. This would allow a high power test run with a sudden blockage. It’s the only way I can come up with to create a not so dramatic reinactment. Your test stand would be a better platform then the airplane. The engine was popping and shaking when the failure occurred. As best I can remember my wideband O2 was off the scale lean but I’m not certain. Speaking of wideband O2’s. My wideband has always jumping around a few 10ths or more. My EM3 get’s a narrowband output from the wideband. The EM3’s mixture bar appears stable. Could the wideband be seeing a injector bounce associated with the injector delay? As an example when leaned for cruise, say 13.2 it’s often switching rapidally between 13.1 and 13.3. At this point the engine seems reasonable smooth. The larger the bounce the less smooth the engine becomes. Have you done any of your testing with a wideband?
Bobby