| Jeff,
Your muffler may be disintegrating from within. That's what happened to my Hushpower II, but then it was pretty close the the exhaust ports. I would take it off and give it a good shake. At the very least, take a look inside.
Mark On Thu, Apr 15, 2010 at 10:35 AM, Jeff Whaley <jwhaley@datacast.com> wrote:
Mark, do you care to elaborate?
Should I be looking for leaks? Or loose, rattling material within?
I am using the HushPower II … Jeff
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Mark Steitle
Sent: Thursday, April 15, 2010 11:28 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Weird sound during descent
Jeff,
From my experience, the first place I would look is at the muffler.
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
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