X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost04.isp.att.net ([207.115.11.54] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3734600 for flyrotary@lancaironline.net; Sat, 27 Jun 2009 11:48:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=207.115.11.54; envelope-from=bbradburry@bellsouth.net Received: from desktop (adsl-146-126-115.mco.bellsouth.net[72.146.126.115]) by isp.att.net (frfwmhc04) with SMTP id <20090627154748H0400esut4e>; Sat, 27 Jun 2009 15:47:49 +0000 X-Originating-IP: [72.146.126.115] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: More progress, more questions.... Date: Sat, 27 Jun 2009 11:47:52 -0400 Message-ID: <8C963ABE35134255B2234F871024C26E@Desktop> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C9F71D.1ACD8A80" X-Mailer: Microsoft Office Outlook 11 Thread-Index: Acn3NAa6n7nnLFzeR5WWcyuei6JD/QACfTow X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C9F71D.1ACD8A80 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Al, Good catch on the voltage! Chris shouldn't tune without the alternator on. The rpm indication could be crosstalk if the power wires are not shielded and are in a conduit with other wires. The low voltage combined with the voltage loss with the small wires in a long run will slow the injectors down and make tuning very difficult. No telling what would be the result. Bill B _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen Sent: Saturday, June 27, 2009 11:32 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: More progress, more questions.... I am concerned about some sputtering that is present around idle. It is generally pretty smooth, but sputters too. Not sure what is causing it yet. Thoughts? Don't know exactly you definition of sputtering, But could be a combination of factors, including some mixture tuning required. My engine is smooth down to about 1500, then begins to miss the occasional beat as I slow it further, and gets a bit rough down at 1000. It might help if you can figure out why you have to 'pump' the throttle to make it slow down. I don't have a clue about the RPM inconsistency, but on the photo of the EM2 panel it looks like voltage is 11.1, but can't tell for sure. Did you not have the field current on the alternator? If you tune the engine with the voltage at about 14.0; then run at 11, it will be out of tune, and probably idle rough. This becomes more of an issue with the small power wires and associated voltage drop. Next, in the documentation for the EC2, the diagrams and part of the text it shows that most of the wires should be run using 22 and/or 20 AWG wire for the connections. However, in ONE place in the document it states that the power wire to the coils should be 16 AWG. I don't think that's an inconsistency, perhaps a misunderstanding. I think the 22 and 20 ga. refers to all the wiring between the PCM and the EC2; The power leads to the coils and injectors are a separate issue. As Ed points out, there will be undesirable voltage drop in a 20 ga, perhaps worse than Ed mentioned because the peak currents, especially for the injectors, will be greater than 10A. I'd also be a bit concerned about the heating in the wires enclosed in a tube; although I'm not sure what the 'average' current is. If it is 10 amps the 20 ga. is going to get warm up; which increases the resistance, etc. I know it's a PITA; but if it were me, I'd bite the bullet and change to 16 ga. Oh, a final comment on progress. My cooling continues to impress me. I'm impressed with your cooling as well. Mine is good now, but I had to make a few changes after first flight to get it there. Poco a poco, se va lejos, Al ------=_NextPart_000_0006_01C9F71D.1ACD8A80 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Al,

Good catch on the voltage!  Chris shouldn’t tune = without the alternator on.

The rpm indication could be crosstalk if the power wires are not shielded and are in a conduit with other wires.  The low voltage = combined with the voltage loss with the small wires in a long run will slow the injectors down and make tuning very = difficult.

No telling what would be the = result.

Bill B 

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen
Sent: Saturday, June 27, = 2009 11:32 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = More progress, more questions....

I am concerned about some sputtering that is present around idle.  It = is

generally pretty smooth, but sputters too. Not sure what is causing it =

yet.  Thoughts?

 

Don’t = know exactly you definition of sputtering, But could be a combination of = factors, including some mixture tuning required. My engine is smooth down to = about 1500, then begins to miss the occasional beat as I slow it further, and gets a = bit rough down at 1000. It might help if you can figure out why you have to ‘pump’ the throttle to make it slow = down.

 

I don’t = have a clue about the RPM inconsistency, but on the photo of the EM2 panel it = looks like voltage is 11.1, but can’t tell for sure.  Did you not = have the field current on the alternator? If you tune the engine with the voltage = at about 14.0; then run at 11, it will be out of tune, and probably idle rough. = This becomes more of an issue with the small power wires and associated = voltage drop.

 

Next, in the documentation for the EC2, the diagrams and part of the =

text it shows that most of the wires should be run using 22 and/or 20 =

AWG wire for the connections.  However, in ONE place in the document it =

states that the power wire to the coils should be 16 = AWG.

 

I don’t = think that’s an inconsistency, perhaps a misunderstanding.  I think = the 22 and 20 ga. refers to all the wiring between the PCM and the EC2; The = power leads to the coils and injectors are a separate issue. As Ed points out, = there will be undesirable voltage drop in a 20 ga, perhaps worse than Ed = mentioned because the peak currents, especially for the injectors, will be greater = than 10A.  I’d also be a bit concerned about the heating in the = wires enclosed in a tube; although I’m not sure what the = ‘average’ current is.  If it is 10 amps the 20 ga. is going to get warm up; = which increases the resistance, etc.  I know it’s a PITA; but if it = were me, I’d bite the bullet and change to 16 = ga.

 

Oh, a final comment on progress.  My cooling continues to impress me. =

 

I’m = impressed with your cooling as well.  Mine is good now, but I had to make a = few changes after first flight to get it there.

 

Poco a poco, = se va lejos,

 

Al

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