Jeff Spitzer wrote:

Neil A. Kruiswyk wrote:

    All we can say for sure is changing to my IVO 3 blade prop made the
noise go away.  Whether it's because of three blades or perhaps a

difference

in weight, who knows.  We checked his 2 blade wood prop for balance and
pitch (between the blades) and it is virtually perfect in all regards.

It is not likely due to the inertia difference.  Resonant frequency is a
function of the square root of the mass/stiffness ratio.  Large changes in
one or both are required to substantially effect the resonance.  The props
probably only change the inertia slightly in the resonance sense.  My guess
is that it is airframe related.

Jeff Spitzer

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