X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 12 Aug 2010 22:54:41 -0400 Message-ID: X-Original-Return-Path: Received: from imr-ma02.mx.aol.com ([64.12.206.40] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTP id 4428708 for lml@lancaironline.net; Thu, 12 Aug 2010 17:37:53 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.206.40; envelope-from=Sky2high@aol.com Received: from imo-da02.mx.aol.com (imo-da02.mx.aol.com [205.188.169.200]) by imr-ma02.mx.aol.com (8.14.1/8.14.1) with ESMTP id o7CLb5no023069 for ; Thu, 12 Aug 2010 17:37:05 -0400 Received: from Sky2high@aol.com by imo-da02.mx.aol.com (mail_out_v42.9.) id q.bdc.675bf7cd (43894) for ; Thu, 12 Aug 2010 17:37:04 -0400 (EDT) Received: from magic-d21.mail.aol.com (magic-d21.mail.aol.com [172.19.155.137]) by cia-dc05.mx.aol.com (v129.4) with ESMTP id MAILCIADC057-ab764c64698031b; Thu, 12 Aug 2010 17:37:04 -0400 From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Thu, 12 Aug 2010 17:37:03 EDT Subject: Re: [LML] Re: Prop Balance X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_d3e8.fecd66b.3995c37f_boundary" X-Mailer: AOL 9.5 sub 155 X-AOL-IP: 24.15.17.119 X-Spam-Flag:NO X-AOL-SENDER: Sky2high@aol.com --part1_d3e8.fecd66b.3995c37f_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Wolfgang, The harmonic damper you refer to (12 pounds, bolts to Lyc flywheel) contains a steel ring in viscous silicone. Its purpose is to dampen negative torque pulses and to provide for more flywheel momentum. It is especially effective for light wooden props (rpm increase of approximately 100) but also serves it purpose with CS props even though the result appears to be un-measurable. Review the torsional effects of a 4 cylinder engine here: _http://www.epi-eng.com/piston_engine_technology/torsional_excitation_from_p iston_engines.htm_ (http://www.epi-eng.com/piston_engine_technology/torsional_excitation_from_piston_engines.htm) It contributes nothing to dynamic prop balance :-( Grayhawk In a message dated 8/12/2010 3:45:09 P.M. Central Daylight Time, Wolfgang@MiCom.net writes: Or put a silicon filled balance ring at the prop hub :-) Wolfgang ____________________________________ From: "Kent" Sender: Subject: Re: [LML] Re: Prop Balance Date: Thu, 12 Aug 2010 14:28:09 -0400 To: lml@lancaironline.net Vibration sensor is placed on engine to measure how engine is moving in space. Prop imbalance will make engine move in bigger circle. So mayny Millivolts are genrated per vibration severity. Relative location of heavy spot is signaled by photo cell, or strobe light flash as heavy spot passes and polarity changes. Up-down = plus-minus. The prop's static weigh slugs can be adjusted or large area washers can be bolted to spinner bulkhead to counterbalance the heavy spot. How much depends weigh depends on how much imbalance there was to begin with. Common to have 10-30 grams of weight for a momento of 100-200 inch pounds. Kent Felkins Tulsa Oklahoma ----- Original Message ----- From: "Greenbacks, UnLtd." To: Sent: Thursday, August 12, 2010 7:20 AM Subject: [LML] Re: Prop Balance Could one of you describe the process of dynamically balancing a typical prop? My old brain cannot visualize how weights are attached. Angier Ames N4ZQ -- For archives and unsub _http://mail.lancaironline.net:81/lists/lml/List.html_ (http://mail.lancaironline.net:81/lists/lml/List.html) --part1_d3e8.fecd66b.3995c37f_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Wolfgang,

The harmonic damper you refer to (12 pounds, bolts to Lyc flywheel)= =20 contains a steel ring in viscous silicone. Its purpose is to dampen= =20 negative torque pulses and to provide for more flywheel momentum. It= is=20 especially effective for light wooden props (rpm increase of approximately= =20 100) but also serves it purpose with CS props even though t= he=20 result appears to be un-measurable. Review the torsional= =20 effects of a 4 cylinder engine here:

http://www.epi-eng.com/piston_engine_= technology/torsional_excitation_from_piston_engines.htm

It contributes nothing to dynamic prop balance :-(

Grayhawk

In a message dated 8/12/2010 3:45:09 P.M. Central Daylight Time,=20 Wolfgang@MiCom.net writes:

Or put a silicon filled balance ring at= the prop=20 hub :-)

Wolfgang

From: "Kent"=20 <kent@tulsaconnect.com>

Sender: <marv@lancaironline.net>=

Subject: Re: [LML] Re: Prop Balance

Date: Thu, 12 Aug 2010 14:28:09=20 -0400

To: lml@lancaironli= ne.net

Vibration sensor is placed on engine to= measure=20 how engine is moving in space. Prop imbalance will make engine= move=20 in bigger circle. So mayny Millivolts are genrated per vibratio= n=20 severity. Relative location of heavy spot is signaled= by=20 photo cell, or strobe light flash as heavy spot passes and polarit= y=20 changes. Up-down =3D plus-minus. The prop's static we= igh=20 slugs can be adjusted or large area washers can be bolted to spinn= er=20 bulkhead to counterbalance the heavy spot. How much depends= weigh=20 depends on how much imbalance there was to begin with. Comm= on to=20 have 10-30 grams of weight for a momento of 100-200 inch=20 pounds. Kent Felkins Tulsa Oklahoma ----- Ori= ginal=20 Message ----- From: "Greenbacks, UnLtd." <N4ZQ@comcast.net><= BR>To:=20 <lml@lancaironline.net> Sent: Thursday, August 12, 2010= 7:20=20 AM Subject: [LML] Re: Prop Balance Could one of you describe the process of dynamicall= y=20 balancing a typical prop? My old brain cannot visualize ho= w=20 weights are attached. Angier Ames N4ZQ -- Fo= r=20 archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html

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