Forwarded from the bounce bin. Message is from
B arry <wrenford@snowy.net.au>
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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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