Re: What is "synchronizing" propellers and why was it done?

Date:         21 Dec 97 17:01:32 
From: (Lou Hinshaw)
Organization: MindSpring Enterprises, Inc.
References:   1 2
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"John E. Kuslich" <> wrote:
>Unsynchronized propellers provide a much more intense vibration in the low
>frequency part of the spectrum than do synchronized propellers.  This is
>because beat notes form at the sum and difference frequencies of the propeller
>rotations.  Not only is this vibration extremely annoying and causes fatigue,
>but it is much more stressfull on structural components which may have
>   resonances      at these frequencies and endanger the structure if allowed to

I added the spaces around the word RESONANCE.  The vibration does not
require resonance, all it need do is be heavy enuff to  flex a part of metal.
This will speed up the aging of the metal badly.  The engines will resonate
in disonnance and transfer the vibration to the airframe.
Flex, flex, flex . . .

Lou H.
Prolific inventor,
Lousy Salesman,
Incompetent businessman.
(Typical of the Breed)
Tulsa OK, USA