My camcorder (Mitsubishi C50) has an integral digital stopwatch facility
which has runs at seconds/100 which presumably is pretty accurate and
almost certainly runs off the synch generator. I am sure this must be
quite a common facility. By superimposing this on a recording of the prop
(with a 'short shutter duration') you might be able use slow-motion/frame
advance to check the actual number of revolutions in so many seconds
Putting a different coloured label on each blade of the prop should be
helpful. It would be especially interesting to use red, green and blue
labels in the same relative positions. Even if your camcorder does not
have a stop-watch you could arrange to get an actual clock in the picture
and maybe the tachometer too. Do not forget the sound channel. With a
suitable plugged-in microphone you could log the tachometer reading
verbally.
Eric Evers
Largs, Ayrshire,
SCOTLAND - UK
-----Original Message-----
From: Duncan McFadyean [SMTP:Halcrow_MRO@compuserve.com]
Sent: 15 October 1997 14:04
Subject: Re: Calibrating Engine RPM
Thanks for the notes on video camera shutter speeds.
Can anyone comment on just how accurate the frame frequency is and
therefore how reliable the technique is?
Duncan McFadyean
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