X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from web81205.mail.mud.yahoo.com ([68.142.199.109] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with SMTP id 1924867 for flyrotary@lancaironline.net; Fri, 16 Mar 2007 13:32:10 -0400 Received-SPF: none receiver=logan.com; client-ip=68.142.199.109; envelope-from=mike.lafleur@sbcglobal.net Received: (qmail 9799 invoked by uid 60001); 16 Mar 2007 17:30:59 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=sbcglobal.net; h=X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type:Message-ID; b=3UHek705QXI5+WS1HuAxcE+tM0bMUJNv22syT1YNDPTP6vHMgC5UGh6yQNYaHYYRbph5FBJBRNQognjvDsI8Z2CA4hzNiQzu/SzkWTgCnRpcDS+T6tgWLWEJQG6Oxldu5ikBQNNrjsrc46FDG/XG4YQergt6i38759epkDGJ29I=; X-YMail-OSG: iobY70EVM1lTQSMYAdReOyHv4976X4avZYQp9z.sOgHJZz5nMjQxzv5Uh7qsylJUHLwfVlyweuYaBN.OskGDLmJRowd5c4Ze1S2S9vX7cZwrZc2abmeIFZh_SjmnR0zsYtbeNaxyKIri808GAGbFoG7uzA-- Received: from [12.41.112.201] by web81205.mail.mud.yahoo.com via HTTP; Fri, 16 Mar 2007 10:30:59 PDT X-Mailer: YahooMailRC/368.8 YahooMailWebService/0.6.132.8 Date: Fri, 16 Mar 2007 10:30:59 -0700 (PDT) From: Michael LaFleur Subject: Re: [FlyRotary] Re: Engine noise and changes in timeing and mixture. To: Rotary motors in aircraft MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1985249886-1174066259=:97114" Message-ID: <241008.97114.qm@web81205.mail.mud.yahoo.com> --0-1985249886-1174066259=:97114 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable With a proper clamp diode, injector delay should be negligible, in the 10's= of microseconds with no noticeable difference between injector types.=0A= =0AHowever, if the clamping diode is between 30-40 volts, you will have pro= blems with brass wound injectors.=0A=0AMike LaFleur (Stayed in a Westin las= t night, not a Holiday Inn Express, so TIFWIW)=0A=0A----- Original Message = ----=0AFrom: Tracy Crook =0ATo: Rotary motors in aircraft <= flyrotary@lancaironline.net>=0ASent: Friday, March 16, 2007 12:15:34 PM=0AS= ubject: [FlyRotary] Re: Engine noise and changes in timeing and mixture.=0A= =0A=0A=0A =0A=0A=0A=0A=0A =0A=0A=0AMaybe not, Bill. Without the snubbers, = there would be some =0Aunknown and =0Apossibly variable delay in the closin= g. There would also =0Apossibly be =0Avarying delays between different inj= ectors. This =0Avariability might not =0Abe enough to feel a vibration, bu= t the exhaust pulse =0Awould be slightly =0Astronger from one chamber than = the other. It would =0Aonly be detected as =0Amore noise and would express= itself as a slop factor in =0Atuning. Remove =0Athe variability and the t= uning can be more exact since =0Athe same amount =0Aof fuel will be deliver= ed every time, giving Tracy that =0Aextra =0A100RPM.=0A=0APossible?=0A =0A = =0A,|"|"|, =0AErnest Christley |=0A=0A=0APossibl= e as anything else I can think of right now. The 'variability' =0Atheory c= ould explain a lot. I know that the *average* mixture is the same =0Aas be= fore (after correcting the IPW) but it is quite possible that there was a = =0Alot of jitter in the pulse width causing cycle to cycle mixture to vary = a =0Alot which the mixture monitor would not show.=0A=0A =0A=0AI hesitate t= o throw more non-engineering terms into the discussion but =0Asometimes tho= se are the only clues we have to start with. The engine does =0Aseem "cris= per" and more responsive to throttle changes. Very =0Ainteresting that Ste= ve perceived a similar change in engine noise =0Atoo. =0A=0A =0A=0ATracy (b= ack from more house renovation) =0A=0A=0A=0A=0A=0A --0-1985249886-1174066259=:97114 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable

With a proper clamp diode, injector delay should be negligible, in t= he 10's of microseconds with no noticeable difference between injector type= s.

However, if the clamping diode is between 30-40 volts, you will h= ave problems with brass wound injectors.

Mike LaFleur (Stayed in a W= estin last night, not a Holiday Inn Express, so TIFWIW)

--= --- Original Message ----
From: Tracy Crook <lors01@msn.com>
To= : Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Fr= iday, March 16, 2007 12:15:34 PM
Subject: [FlyRotary] Re: Engine noise a= nd changes in timeing and mixture.

=0A=0A =0A=0A=0A= =0A

=0A

=0A

Maybe not, Bill. Without the = snubbers, there would be some =0Aunknown and
possibly variable delay in= the closing. There would also =0Apossibly be
varying delays betw= een different injectors. This =0Avariability might not
be enough = to feel a vibration, but the exhaust pulse =0Awould be slightly
stronge= r from one chamber than the other. It would =0Aonly be detected as more noise and would express itself as a slop factor in =0Atuning. = Remove
the variability and the tuning can be more exact since =0Athe sa= me amount
of fuel will be delivered every time, giving Tracy that =0Aex= tra =0A100RPM.

Possible?

= =0A,|"|"|, &nbs= p; =0AErnest Christley = ; |

=0A

Possible as anything else I can think of r= ight now. The 'variability' =0Atheory could explain a lot. I kn= ow that the *average* mixture is the same =0Aas before (after correcting th= e IPW) but it is quite possible that there was a =0Alot of jitter in the pu= lse width causing cycle to cycle mixture to vary a =0Alot which the mi= xture monitor would not show.

=0A

=0A

I hesitate t= o throw more non-engineering terms into the discussion but =0Asometime= s those are the only clues we have to start with. The engine does =0A= seem "crisper" and more responsive to throttle changes. Very =0A= interesting that Steve perceived a similar change in engine noise =0At= oo.

=0A

=0A

Tracy (back from more house reno= vation) =0A

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