X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from exhub003-1.exch003intermedia.net ([207.5.74.28] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTPS id 4013867 for flyrotary@lancaironline.net; Thu, 10 Dec 2009 10:13:42 -0500 Received-SPF: none receiver=logan.com; client-ip=207.5.74.28; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by exhub003-1.exch003intermedia.net ([207.5.74.28]) with mapi; Thu, 10 Dec 2009 07:13:04 -0800 From: Jeff Whaley To: Rotary motors in aircraft Date: Thu, 10 Dec 2009 07:14:04 -0800 Subject: RE: [FlyRotary] Re: EC2 signals Thread-Topic: [FlyRotary] Re: EC2 signals Thread-Index: Acp5P8zNngUB90tSQeWWWbPaaqyweAAYyEXw Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_C03ABB0A7362B84BB53D544B3C305E0E0153A492C20FEXVMBX0035e_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0E0153A492C20FEXVMBX0035e_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Steve: Yes, excellent work and report. I understand the part about random EC2 dwell times during starting causing = the weak or non-existent spark but I'm not 100% clear on the relationship t= o Mode 8 timing retard and the overall ignition timing result at cruise or = WOT settings. Your conclusion states: " A mode 8 setting of 10 degrees reta= rded is used for starting. Desired ignition timing is achieved by setting t= he CAS physical position in the engine block to compensate for this." Does this mean that the standard mechanical setting of 35 BTDC should be ch= anged to 45 BTDC to compensate for the Mode 8, 10 degree retard? What was the net ignition timing at high rpm result from this experiment? If I understand the EC2 timing correctly, once you set it to +/- zero it af= fects the entire operating range. A retarded timing would definitely impro= ve starting and low idle but you have now also limited the maximum advance = at cruise or WOT. It would be great if the EC2 could have 2 timing setting= s based on rpm, similar to the 2 MAP ranges of below and above staging. Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Al Gietzen Sent: Wednesday, December 09, 2009 9:23 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: EC2 signals Steve; You are to be commended for some very scholarly work, and excellent reporti= ng. There are many hours invested there, as well as expenses for equipment= . For nearly 2 years now I have been puzzled by my observation of spark condi= tions during cranking that are consistent with your findings. Since my eng= ine has always started, and run well, I didn't have motivation to pursue th= e causes. It may also be at least part of the explanation for the inabilit= y to get smooth operation below 1200 rpm. Of course my EC2 has been updated since, so I don't know if the behavior is= still the same. Coincidentally, just this past week I have done some further tests of timin= g adjustment. You my recall from my dyno report that the timing of my engi= ne as I received it was way off because of the use of a 12A front cover (an= d pointer) on the 20B engine. We set the CAS position based on estimated T= DC by observing the tip seals between the leading and trailing plug holes. = During the testing we verified the timing based on a trace from a pressure= transducer in a trailing plug hole; and decided that about -2 steps on the= EC2 it 'looked right'. I've been running that way since (and the 2 steps = retarded may have been a plus as far as starting spark is concerned). Some time back I had varied the timing a couple of steps during static runu= p; and could not discern a difference, so I left it as is. I haven't bothe= red with in-flight variation, partly because I was a bit hesitant to be cha= nging it during flight. I finally did so at lean cruise conditions, and fou= nd that about 3 more steps retarding made a discernable increase in rpm (54= 50 to 5500). So my EC2 is now set at -10 degrees from default. I haven't = yet made any further spark checks, or even observed if low idle is any smoo= ther. I may retard a bit on the CAS, and then do some more observation to see if = there is an 'optimum'. Then set one of the controllers 5 steps retarded fo= r use in starting. I guess you have now added to Tracy's TTD list to figure out what, if anyth= ing, should be done as a result. Al -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of sboese Sent: Wednesday, December 09, 2009 2:30 PM To: Rotary motors in aircraft Subject: [FlyRotary] EC2 signals Steve, Al and others who may be interested in EC2 ignition characteristics, I have added a page to the http://www.rotarycopilot.com/ website which is a= n attempt to show why I choose to use a 10 degree retarded mode 8 ignition timing setting. This setting is beneficial for startup and very slow idle with my EC2's. The previously mentioned download to this information has been removed from the website's downloads page. Now the information can be viewed directly without having to download, unzip, and open the html file. With the version of Internet Explorer I have, it is possible to click on an image from the web site page and download the original if a clearer image i= s desired. Steve Boese -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.= html --_000_C03ABB0A7362B84BB53D544B3C305E0E0153A492C20FEXVMBX0035e_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Steve:

Yes, excellent work and report.

I understand the part about random EC2 dwell times during starting causing the weak or non-existent spark but I’m not 100% clea= r on the relationship to Mode 8 timing retard and the overall ignition timing re= sult at cruise or WOT settings. Your conclusion states: “ A mode 8 setting= of 10 degrees retarded is used for starting. Desired ignition timing is achiev= ed by setting the CAS physical position in the engine block to compensate for = this.”

Does this mean that the standard mechanical setting of 35 BT= DC should be changed to 45 BTDC to compensate for the Mode 8, 10 degree retard= ?

What was the net ignition timing at high rpm result from thi= s experiment?

 

If I understand the EC2 timing correctly, once you set it to= +/- zero it affects the entire operating range.  A retarded timing would definitely improve starting and low idle but you have now also limited the maximum advance at cruise or WOT.  It would be great if the EC2 could = have 2 timing settings based on rpm, similar to the 2 MAP ranges of below and ab= ove staging.

Jeff

 

 

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietze= n
Sent: Wednesday, December 09, 2009 9:23 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: EC2 signals

 

= Steve;

=  

= You are to be commended for some very scholarly work, and excellent reporting. = ; There are many hours invested there, as well as expenses for equipment.

=  

= For nearly 2 years now I have been puzzled by my observation of spark condition= s during cranking that are consistent with your findings.  Since my engi= ne has always started, and run well, I didn't have motivation to pursue the causes.  It may also be at least part of the explanation for the inabi= lity to get smooth operation below 1200 rpm.

=  

= Of course my EC2 has been updated since, so I don’t know if the behavior= is still the same.

=  

= Coincidentally, just this past week I have done some further tests of timing adjustment.&nb= sp; You my recall from my dyno report that the timing of my engine as I receive= d it was way off because of the use of a 12A front cover (and pointer) on the 20= B engine.  We set the CAS position based on estimated TDC by observing t= he tip seals between the leading and trailing plug holes.  During the tes= ting we verified the timing based on a trace from a pressure transducer in a trailing plug hole; and decided that about -2 steps on the EC2 it 'looked right'.  I've been running that way since (and the 2 steps retarded ma= y have been a plus as far as starting spark is concerned).<= /p>

=  

= Some time back I had varied the timing a couple of steps during static runup; an= d could not discern a difference, so I left it as is.  I haven’t bothered with in-flight variation, partly because I was a bit hesitant to b= e changing it during flight. I finally did so at lean cruise conditions, and found that about 3 more steps retarding made a discernable increase in rpm (5450 to 5500).  So my EC2 is now set at -10 degrees from default.&nbs= p; I haven’t yet made any further spark checks, or even observed if low id= le is any smoother.

=  

= I may retard a bit on the CAS, and then do some more observation to see if there = is an ‘optimum’.  Then set one of the controllers 5 steps retarded for use in starting.

=  

= I guess you have now added to Tracy’s TTD list to figure out what, if anythin= g, should be done as a result.

=  

= Al

=  

=  

=  

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of sboese
Sent: Wednesday, December 09, 2009 2:30 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] EC2 signals

 

Steve, Al and others who may be interested in EC2 ignition characteristics,

 

I have added a page to the http://www.rotarycopilot= .com/ website which is an

attempt to show why I choose to use a 10 degree ret= arded mode 8 ignition

timing setting.  This setting is beneficial fo= r startup and very slow idle

with my EC2's. 

The previously mentioned download to this informati= on has been removed from

the website's downloads page.  Now the informa= tion can be viewed directly

without having to download, unzip, and open the htm= l file.

With the version of Internet Explorer I have, it is possible to click on an

image from the web site page and download the origi= nal if a clearer image is

desired.

 

Steve Boese

   

 

 

--

Homepage:  http://www.flyrotary.com/

Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html

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