Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3140268 for flyrotary@lancaironline.net; Thu, 01 Apr 2004 07:57:27 -0500 Received: from edward (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i31CvOkG018723 for ; Thu, 1 Apr 2004 07:57:26 -0500 (EST) Message-ID: <004f01c417e8$e305b4b0$2402a8c0@edward> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Rusty's O2 / EM2 problems. Date: Thu, 1 Apr 2004 07:57:27 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004C_01C417BE.F9FB2F30" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_004C_01C417BE.F9FB2F30 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageRusty, interesting theory, but I would be inclined to discount = fuel droplets as a factor in your rich indicator readings. You say you = can hear the engine as it leans and richens indicating that your mixture = knob is working. Generally full rich readings indicate a voltage of = near 1.0 volts from the O2 sensor. If you really want to check out the = O2 sensor, hook a high impedance volt/ohm meter into its out put and see = what the voltage swing is as you vary the mixture control. =20 On mine max rich is around 1.0 volts, mids scale gives me around = 0.45-0.6 volts, low end drops off around 0.1.5 - 0.2 volts. Is the O2 sensor you are using a heated 3/4 wire unit? If so I am = wondering whether you might possibly have a ground loop feeding heater = voltage onto your sensor lead? Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Thursday, April 01, 2004 7:40 AM Subject: [FlyRotary] Re: Rusty's O2 / EM2 problems. Greetings, I haven't had a chance to do anything else with my O2 testing, but = I've had an odd thought. =20 The full story, is that I originally had erratic O2 readings with the = rev-2 configuration. Primarily, this was staying on the mid, to low end = of the scale, but would then just go away completely, as if it was way = too lean. I had used the same sensor I used before, but now had the = EM-2, rather than my old mixture gauge. It didn't take long before I = noticed that the O2 sensor was falling apart, so it was replaced with = the Bosch 11027 sensor that several of you are using. On the next run, = the EM-2 read almost full scale, and I couldn't do much to change it = with the mixture knob. I could hear the engine getting richer and = leaner, but the reading stayed near full scale. The only time it would = change was when I leaned so much that the engine was starting to cut = out, then it would plunge to nearly zero. =20 I'll be testing the reading with my old mixture gauge very shortly, so = we'll see what that shows, but by all rights, the EM-2 should be giving = me a valid reading. If we assume it's correct, then I'm running so = rich, that the O2 reading is maxed through the whole usable mixture = range required to run. =20 Here's the wild question- Is it possible that the fuel is not = atomizing completely due to the 30" distance from my injectors to the = engine, and some of it is making it through the engine as "droplets". = It's hard for me to believe that could really happen, but it would = explain the overly rich O2 reading. =20 Thanks, Rusty (shouldn't ask questions so early) ------=_NextPart_000_004C_01C417BE.F9FB2F30 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Rusty, interesting theory, but I would be = inclined to=20 discount fuel droplets as a factor in your rich indicator = readings.  You=20 say you can hear the engine as it leans and richens indicating that your = mixture=20 knob is working.   Generally full rich readings indicate a = voltage of=20 near 1.0 volts from the O2 sensor.  If you really want to check out = the O2=20 sensor, hook a high impedance volt/ohm meter into its out put and see = what the=20 voltage swing is as you vary the mixture control. 
 
On mine max rich is around 1.0 volts, mids scale = gives me=20 around 0.45-0.6 volts, low end drops off around 0.1.5 - 0.2 = volts.
 
Is the O2 sensor you are using a heated 3/4 wire = unit?  If so I am wondering whether you might possibly have a = ground loop=20 feeding heater voltage onto your sensor lead?
 
Ed
 
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Thursday, April 01, 2004 = 7:40=20 AM
Subject: [FlyRotary] Re: = Rusty's O2 / EM2=20 problems.

Greetings,
 
I = haven't had a=20 chance to do anything else with my O2 testing, but I've had an odd=20 thought. 
 
The = full story, is=20 that I originally had erratic O2 readings with the rev-2 = configuration. =20 Primarily, this was staying on the mid, to low end of the scale, but = would=20 then just go away completely, as if it was way too lean.   I = had=20 used the same sensor I used before, but now had the EM-2, rather than = my old=20 mixture gauge.  It didn't take long before I noticed that the O2 = sensor=20 was falling apart, so it was replaced with the Bosch 11027 sensor that = several=20 of you are using.  On the next run, the EM-2 read almost = full scale,=20 and I couldn't do much to change it with the mixture knob.  I = could hear=20 the engine getting richer and leaner, but the reading stayed near full = scale.  The only time it would change was when I leaned so much = that the=20 engine was starting to cut out, then it would plunge to=20 nearly zero.  
 
I'll = be testing=20 the reading with my old mixture gauge very shortly, so we'll see what = that=20 shows, but by all rights, the EM-2 should be giving me a valid=20 reading.  If we assume it's correct, then I'm running so rich, = that the=20 O2 reading is maxed through the whole usable mixture range required to = run.  
 
Here's the wild=20 question-   Is it = possible that=20 the fuel is not atomizing completely due to the 30" distance from = my=20 injectors to the engine, and some of it is making it through the = engine=20 as "droplets".  It's hard for me to believe that could really = happen,=20 but it would explain the overly rich O2=20 reading.  
 
Thanks,
Rusty (shouldn't=20 ask questions so=20 early)   
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