Mailing List flyrotary@lancaironline.net Message #50909
From: Jeff Whaley <jwhaley@datacast.com>
Subject: Weird sound during descent
Date: Thu, 15 Apr 2010 08:13:10 -0700
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

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 zzuuzz, 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 that lifted me against the seat belts -- the noise stopped.

Tracy had cautioned me against low power steeps descents, something about thrust 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 what 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 signature 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 addressee and may contain privileged or confidential information. Any unauthorized 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.
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster