X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from web46411.mail.sp1.yahoo.com ([68.180.199.200] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with SMTP id 4222591 for flyrotary@lancaironline.net; Thu, 15 Apr 2010 11:39:38 -0400 Received-SPF: none receiver=logan.com; client-ip=68.180.199.200; envelope-from=dwayneparkinson@yahoo.com Received: (qmail 35943 invoked by uid 60001); 15 Apr 2010 15:39:00 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1271345940; bh=LD0cvO7SgHrgdB6R9cqJENFas47x+/r/4MbPHhSJV3w=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=wEafIXLVlDuO5Z77v7nRSwIWsAEc/oBi9hSw+zzetKNbaHn5kEpCuUj4LFKHKz+N/RiGyjxLqf3k5XwhqchEfZUDEVcIhXz3VxYDE6nO4YLP+iPuDrS/TzZCGicKxAiIXmkr2qU19RwHKNJNfLCDC2zOAmAsv+lNV1PCjk6g3Ow= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=AJp+45k6hThWBgZNOe3B7CTObo/hXlkrG3I/uI11XENKOMLq1blKBGXH0DYhMOWnkqFSU7VTvmJuFyl1dRTsrcmGlDAwLn8K82NMLADtyoqcbgoPYK8m47QCeO4TjJGPifflVEamMaaYkHAEtkFqHKydhJhks7+5MbuFnsyYU5s=; Message-ID: <802196.34823.qm@web46411.mail.sp1.yahoo.com> X-YMail-OSG: dLD2sjEVM1l1wlzSm3H32iAiyQ5nruL.i3Q.ipcGrc506Ft wlku.uRQzw62ALRabZhKz9_XoidBBBDfBJmARLiPj3X.OVvY9jGU77OXmSw. wOdew.IKfqkOm6TqKbep7QsaFJeGMe6GV.BQas.8BA0ZOg9goEkiiW4I8EFm Cud66zaKjG1oGMQo3mrwS1jxkGhmICxHbzgVu8eK9Nsf5ONcNSrNTM21jHQN VOHSGe.2WfauANr1bmTS61POjRK2Zy_NrWJQ5YebX18yRRAXdeF48._DM3oO JjE8OLMVXj___Ru0oWUR7piViIvEj7Zhew3tJfcpE Received: from [24.177.130.10] by web46411.mail.sp1.yahoo.com via HTTP; Thu, 15 Apr 2010 08:39:00 PDT X-Mailer: YahooMailRC/348.5 YahooMailWebService/0.8.100.260964 References: Date: Thu, 15 Apr 2010 08:39:00 -0700 (PDT) From: Dwayne Parkinson Subject: Re: [FlyRotary] Re: Weird sound during descent To: Rotary motors in aircraft In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-446986804-1271345940=:34823" --0-446986804-1271345940=:34823 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Wind noise is easy to check. Get up a few thousand feet and fly a fake dow= nwind and base leg just as you would if you were at pattern altitude. Once= the noise starts, leave the throttle and MP alone but see what happens as = you change attitude. If it's wind related you should be able to figure it = out pretty quickly. Likewise, once the noise starts, level out and do some= slow flight. See if it hangs around. Increase throttle to see if that ma= kes it go away. If it's a harmonic thing in the muffler you'll find out pr= etty quickly too.=0A=0AGood luck.=0A=0A=0ADwayne=0A=0A=0A=0A_______________= _________________=0AFrom: Al Gietzen =0ATo: Rotary moto= rs in aircraft =0ASent: Thu, April 15, 2010 11= :33:39 AM=0ASubject: [FlyRotary] Re: Weird sound during descent=0A=0A =0AJe= ff;=0A =0AHard to tell, but sounds like something=0Avibrating at the partic= ular frequencies set up under those conditions. There=0Aare times I also he= ar strange noises on descents, and very low throttle=0Asettings =E2=80=93 s= ometimes there, sometimes not. You finally just accept them=0Aas normal.=0A= =0ANot likely anything to do with the=0Athrust bearing. I have a pusher a= nd you=E2=80=99d think the forces are=0Areversed; although I guess if the e= ngine is being driven by the prop rather=0Athan vice-versa, the result is t= he same. If there is=0Asome issue about steep descents, I=E2=80=99d like t= o know as well.=0A =0AAl=0A =0A-----Original Message-----=0AFrom: Rotary mo= tors in aircraft=0A[mailto:flyrotary@lancaironline.net] On=0ABehalf Of Jeff= Whaley=0ASent: Thursday, April 15, 2010=0A7:13 AM=0ATo: Rotary motors in a= ircraft=0ASubject: [FlyRotary] Weird sound=0Aduring descent=0A =0AI have be= en hearing a weird buzzing sound usually=0Adetectable on base leg at low po= wer settings. It is hard to describe in=0Atext but is repeatedly as zzuuzz= , zzuuzz, zzuuzz .=0AI thought it was wind noise escaping between the=0Afus= elage and gear legs, as there are no fairings between the fuselage and top= =0Aof the cub-style gear.=0ALast night it was bit bumpy and during one desc= ent=0Athere was a good bump that lifted me against the seat belts -- the no= ise=0Astopped.=0ATracy had cautioned me against low power steeps=0Adescents= , something about thrust bearing and/or snubber =E2=80=93 maybe refresh=0Am= e on that one Tracy?=0AHowever, an approach speed of 500 fpm, 80 mph, 3000= =0Arpm, mp <10=E2=80=9D, is not what I=E2=80=99d consider steep. =0A =0AAny= one care to give me a clue as to what I might be=0Ahearing?=0AIf I get a ch= ance to fly this weekend, I=E2=80=99ll=0Aexperiment to see if I can stop/ch= ange the noise with speed or attitude=0Aadjustments. =0AJeff=0A=0A=0A______= ____ Information from ESET NOD32 Antivirus, version of virus signature=0Ada= tabase 5031 (20100415) __________=0A=0AThe message was checked by ESET NOD3= 2 Antivirus.=0A=0Ahttp://www.eset.com=0A=0AThis message, and the documents = attached hereto,=0Ais intended only for the addressee and may contain privi= leged or confidential=0Ainformation. Any unauthorized disclosure is strictl= y prohibited. If you have=0Areceived this message in error, please notify u= s immediately so that we may=0Acorrect our internal records. Please then de= lete the original message. Thank=0Ayou.=0A=0A=0A --0-446986804-1271345940=:34823 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Wind noise is easy to check.  Get up a few thousand feet and= fly a fake downwind and base leg just as you would if you were at pattern = altitude.  Once the noise starts, leave the throttle and MP alone but = see what happens as you change attitude.  If it's wind related you sho= uld be able to figure it out pretty quickly.  Likewise, once the noise= starts, level out and do some slow flight.  See if it hangs around. &= nbsp;Increase throttle to see if that makes it go away.  If it's a har= monic thing in the muffler you'll find out pretty quickly too.
Good luck.


Dwayne
<= span style=3D"font-weight: bold;">From: Al Gietzen <ALVenture= s@cox.net>
To: Rotar= y motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, April 15, 2010 11:33:39 AMSubject: [FlyRotary] Re: = Weird sound during descent

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

Jeff;

=0A=0A

 

=0A=0A

Hard to tell, but sounds like= something=0Avibrating at the particular frequencies set up under those con= ditions. There=0Aare times I also hear strange noises on descents, and very= low throttle=0Asettings =E2=80=93 sometimes there, sometimes not. You fina= lly just accept them=0Aas normal.

=0A=0A

 

=0A= =0A

= Not lik= ely anything to do with the=0Athrust bearing.  I have a pusher and you= =E2=80=99d think the forces are=0Areversed; although I guess if the engine = is being driven by the prop rather=0Athan vice-versa, the result is the same.  If there is=0Aso= me issue about steep descents, I=E2=80=99d like to know as well.

=0A=0A

 

=0A=0A

Al

=0A=0A

 

=0A=0A

-----Original Messa= ge-----
=0AFrom: Rotary = motors in aircraft=0A[mailto:flyrotary@lancaironline.net] On=0ABehalf Of Jeff Whaley
=0ASent: Thursday, April 15, 2010=0A7:13 = AM
=0ATo: Rotary motors = in aircraft
=0ASubject: = [FlyRotary] Weird sound=0Aduring descent

=0A=0A

<= span style=3D"font-size:11.0pt;"> 

=0A=0A

I have been hearing a weird buzzing sound u= sually=0Adetectable on base leg at low power settings.  It is hard to = describe in=0Atext but is repeatedly as zzuuzz, zzuuzz, zzuuzz .

=0A=0A

I thought it was = wind noise escaping between the=0Afuselage and gear legs, as there are no f= airings between the fuselage and top=0Aof the cub-style gear.=

=0A=0A

Last night it was bit= bumpy and during one descent=0Athere was a good bump that lifted me agains= t the seat belts -- the noise=0Astopped.

=0A=0A

<= span style=3D"font-size:11.0pt;">Tracy had cautioned me against low power s= teeps=0Adescents, something about thrust bearing and/or snubber =E2=80=93 m= aybe refresh=0Ame on that one Tracy?

=0A=0A

However, an approach speed of 500 fpm, 80 mph,= 3000=0Arpm, mp <10=E2=80=9D, is not what I=E2=80=99d consider steep.

=0A=0A

 

=0A=0A

Anyone car= e to give me a clue as to what I might be=0Ahearing?

=0A= =0A

If I get a chance to fly thi= s weekend, I=E2=80=99ll=0Aexperiment to see if I can stop/change the noise = with speed or attitude=0Aadjustments.

=0A=0A

Jeff

=0A=0A


=0A
=0A__________ Information from ESET NOD32 Antivirus, version of= virus signature=0Adatabase 5031 (20100415) __________
=0A
=0AThe mes= sage was checked by ESET NOD32 Antivirus.
=0A
=0Ahttp://www.eset.com
=0A=0AThis message, and th= e documents attached hereto,=0Ais intended only for the addressee and may c= ontain privileged or confidential=0Ainformation. Any unauthorized disclosur= e is strictly prohibited. If you have=0Areceived this message in error, ple= ase notify us immediately so that we may=0Acorrect our internal records. Pl= ease then delete the original message. Thank=0Ayou.

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

=0A=0A --0-446986804-1271345940=:34823--