Hi Everyone,
Thanks for all your replies with suggestions, several of which I'm now following
up. After a thorough in depth investigation with engine cowls off, I've got
a couple more things to try like unclamping the exhaust header tubes and moving
the silencer slightly before tightening again. This is intended to move it a
little further away from the air duct against which it might be vibrating in
flight, when the engine leans over due to torque.
Clive, my mobile 'phone is a Tesco 20 special, which only does calls and texts.
The frequency of the 'wow-wow' doesn't seem to change when I vary rpm in the
cruise, but then I'm only varying it by about 6%. I also can't say that I notice
any change with airspeed. I switch the controller to manual during the cruise
to reduce rpm from 5000 to 4700, so the CS function probably isn't a factor.
Thanks for the pointer regarding one propeller blade tip tracking differently
from
the others. Although the wonderful Airmaster propeller which I've had for
nigh on 20 years is virtually 'bomb proof', I'll definitely investigate.
Best wishes,
Jonathan.
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