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From: "rijakits" <rijakits@cwpanama.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-566618@logan.com>
Subject: Re: [FlyRotary] Re: A First (and note to Perry)
Date: Tue, 14 Dec 2004 00:01:28 -0500
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----- Original Message -----
From: "Marvin Kaye" <marv@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Monday, December 13, 2004 10:41 PM
Subject: [FlyRotary] Re: A First (and note to Perry)


> "Perry Mick" <pjmick@mail.viclink.com> wrote:
>
> """
> I've tried 4 times now to use a computerized dynamic balance
>   system, but it won't converge on a solution. It always worked perfectly
with
>   my direct-drive fan. So it mustn't like geared engines. I'm going to
trial-
>   and-error it by moving a fender washer (weight) from one prop bolt to
the
>   next and see if the vibration level readout increases or decreases, and
try
>   to find a minimum.
> """
>
> I'm curious, Perry, if a fender washer might not be overkill...  last guy
I
> saw had a prop dynamically balanced it took a short #6 screw to get the
job
> done.  Given the size of prop bolts and their associated fender washer
size,
> aren't you concerned that will be _too much_ mass?  I'd think that much
weight
> fladdling around off-center out there at 2000+ rpm would make matters
worse,
> not better.  Like I said, just curious (and concerned).
>
My experience with these electronic balancers is:
a) if you can't get a consistent reading, something is out of spec, a loose
engine mount, worn bearing, off-center mounted/drilled/bored prop
b) balancer out of calibration

c) Generally it takes me about 5 runs to go from an initial run down to
about 0.02 to 0.05 IPS, if it takes more runs and values continue to jump
around "the clock", something is not right, a or b.

My 5cents,

Thomas J.