Mitchell Holman wrote (in part):

"Indrek Aaviso" wrote in
m:

"Mitchell Holman" wrote in message
. 130...
It's interesting how the props are almost perfectly synchronised. Did
that happen just by chance, or is there some kind of automatic
synchronisation?



Chance. Probably happens several times per second.

Most multi-engine prop aircraft have some form of auto-synch, which
just keeps the props at the same rpm as the "master" - normally
switched off during t'off and landing. Some, including C-130s and
even a Cessna 340A which I used to fly, have synchro-phasing. This
keeps the props in the same phase with each other in a pattern
designed to minimise prop noise inside the aircraft by ensuring
multiple pressure pulses from the props do not hit the fuselage skin
at the same time. That's the theory, anyway :-)

--
Mike Mackenzie (AVCOM Services)
Brisbane, AUSTRALIA
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