Try checking the preload setting of the vibration-isolator in the gearbox;
this doesn`t need disassembly.
A clue to this being incorrect is often difficulty in starting.
Duncan McFadyean
-----Original Message-----
From: John Cliff <john@crixbinfield.freeserve.co.uk>
Date: Thursday, May 24, 2001 11:56 AM
Subject: NSI CAP 140 Prop Imbalance
>Forwarded from the bounce bin. Message is from
>B arry <wrenford@snowy.net.au>
>
>******************************************************
>
>Europa XS engine installation, fitted with NSI CAP140 using Warp Drive
>parallel blades on the Rotax 914 is producing excessive vibrations at
>various engine revs. Prop was dynamically balanced to perfection, but
>the vibrations continued. Viewed from the side while running the blades
>are vibrating fore-aft by a total of 1" at their worst. They run true at
>lower revs, and this visible harmonic vibration comes in and out as revs
>are increased.
>
>NSI have already replaced the blades once, and we assume that it is the
>same problem.
>
>All three blades show this fore-aft oscillation
>
>The Rotax 914 does not have the overload clutch for ground strike fitted
>
>An engineer has advised that we do not continue to fly this propeller.
>
>NSI suggests that these vibrations may be induced from the propeller
>gearbox
>
>An Airmaster hub also fitted with Warp Drive blades on another XS is
>exhibiting similar problems.
>
>Has anyone else experienced this problem, or if you have vibrations,
>check the prop 'edge on' at the lowest revs that induce the vibration?
>
>Anybody have any suggestions
>
>Barry Wrenford - Australia No 308
>
>
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