X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-2.exch003intermedia.net ([207.5.74.29] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTPS id 4222600 for flyrotary@lancaironline.net; Thu, 15 Apr 2010 11:48:22 -0400 Received-SPF: none receiver=logan.com; client-ip=207.5.74.29; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-2.exch003intermedia.net ([207.5.74.29]) with mapi; Thu, 15 Apr 2010 08:47:44 -0700 From: Jeff Whaley To: Rotary motors in aircraft Date: Thu, 15 Apr 2010 08:48:38 -0700 Subject: RE: [FlyRotary] Re: Weird sound during descent Thread-Topic: [FlyRotary] Re: Weird sound during descent Thread-Index: AcrcsTiavLHdSkKzRfKbH8f5k0SvOwAAJKqw 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_C03ABB0A7362B84BB53D544B3C305E0E017944B45B2BEXVMBX0035e_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0E017944B45B2BEXVMBX0035e_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Al, if I may add ... or correct, I believe Tracy said "low power, high spee= d descents" ... I said steep, which to me is the same thing. Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Al Gietzen Sent: Thursday, April 15, 2010 12:34 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Weird sound during descent Jeff; Hard to tell, but sounds like something vibrating at the particular frequen= cies set up under those conditions. There are times I also hear strange noi= ses on descents, and very low throttle settings - sometimes there, sometime= s not. You finally just accept them as normal. Not likely anything to do with the thrust bearing. I have a pusher and you= 'd think the forces are reversed; although I guess if the engine is being d= riven by the prop rather than vice-versa, the result is the same. If there= is some issue about steep descents, I'd like to know as well. Al -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Jeff Whaley Sent: Thursday, April 15, 2010 7:13 AM To: Rotary motors in aircraft Subject: [FlyRotary] Weird sound during descent I have been hearing a weird buzzing sound usually detectable on base leg at= low power settings. It is hard to describe in text but is repeatedly as z= zuuzz, zzuuzz, zzuuzz . I thought it was wind noise escaping between the fuselage and gear legs, as= there are no fairings between the fuselage and top of the cub-style gear. Last night it was bit bumpy and during one descent there was a good bump th= at lifted me against the seat belts -- the noise stopped. Tracy had cautioned me against low power steeps descents, something about t= hrust bearing and/or snubber - maybe refresh me on that one Tracy? However, an approach speed of 500 fpm, 80 mph, 3000 rpm, mp <10", is not wh= at I'd consider steep. Anyone care to give me a clue as to what I might be hearing? If I get a chance to fly this weekend, I'll experiment to see if I can stop= /change the noise with speed or attitude adjustments. Jeff __________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 5031 (20100415) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com This message, and the documents attached hereto, is intended only for the a= ddressee and may contain privileged or confidential information. Any unauth= orized disclosure is strictly prohibited. If you have received this message= in error, please notify us immediately so that we may correct our internal= records. Please then delete the original message. Thank you. __________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 5031 (20100415) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 5031 (20100415) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com This message, and the documents attached hereto, is intended only for the a= ddressee and may contain privileged or confidential information. Any unauth= orized disclosure is strictly prohibited. If you have received this message= in error, please notify us immediately so that we may correct our internal= records. Please then delete the original message. Thank you. --_000_C03ABB0A7362B84BB53D544B3C305E0E017944B45B2BEXVMBX0035e_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Al, if I may add ̷= 0; or correct, I believe Tracy said “low power, high speed descents&#= 8221; … I said steep, which to me is the same thing.

Jeff=

 

From: Rotary m= otors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen
Sent: Thursday, April 15, 2010 12:34 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Weird sound during descent

 

Jeff;

 

Hard to tell, but sounds like something vibra= ting at the particular frequencies set up under those conditions. There are= times I also hear strange noises on descents, and very low throttle settings – sometimes there, sometimes not. You finally = just accept them as normal.

 

Not likely anything to do with the thrust bea= ring.  I have a pusher and you’d think the forces are reversed; = although I guess if the engine is being driven by the prop rather than vice-versa, the result is the same.  If there is some issue about ste= ep descents, I’d like to know as well.

 

Al

 

-----Original Messag= e-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]= On Behalf Of Jeff Whaley
Sent: Thursday, April 15, 2010 7:13 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Weird sound during descent

 

I have been hearing a wei= rd buzzing sound usually detectable on base leg at low power settings. = ; It is hard to describe in text but is repeatedly as zzuuzz, zzuuzz, zzuuz= z .

I thought it was wind noi= se escaping between the fuselage and gear legs, as there are no fairings be= tween the fuselage and top of the cub-style gear.

Last night it was bit bum= py and during one descent there was a good bump that lifted me against the = seat belts -- the noise stopped.

Tracy had cautioned me ag= ainst low power steeps descents, something about thrust bearing and/or snub= ber – maybe refresh me on that one Tracy?

However, an approach spee= d of 500 fpm, 80 mph, 3000 rpm, mp <10”, is not what I’d con= sider steep.

 

Anyone care to give me a = clue as to what I might be hearing?

If I get a chance to fly = this weekend, I’ll experiment to see if I can stop/change the noise w= ith speed or attitude adjustments.

Jeff



__________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 5031 (20100415) __________

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This message, and the documents attached hereto, is intended o= nly for the addressee and may contain privileged or confidential informatio= n. Any unauthorized disclosure is strictly prohibited. If you have received this message in error, please notify us i= mmediately so that we may correct our internal records. Please then delete = the original message. Thank you.



__________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 5031 (20100415) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com



__________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 5031 (20100415) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

This message, and the docum= ents attached hereto, is intended only for the addressee and may contain pr= ivileged or confidential information. Any unauthorized disclosure is strict= ly prohibited. If you have received this message in error, please notify us immediately so that we may correct our = internal records. Please then delete the original message. Thank you.
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