"Roger (K8RI)" wrote in message
...
On Sun, 02 Dec 2007 22:09:30 -0000, Jim Logajan
wrote:

At cruise RPM that effect would be completely lost. There's not a
bird or human alive that can discern stroboscopic effects of more than
a couple hundred cycles let alone over a 1000. Most of us can't even
discern 60 cps.



"Mike Noel" wrote in message
...
True, but aren't we talking about 40 cps when the prop RPM is 2400?


Seems I have heard the 16 cps is all that is required for movies to appear
continuous. I think the human eye loosed it around 12 or 13. However, we
don't seen consciously either. Hence the reason an aircraft propeller will
appear to be revolving slowly backwards at times.

I can say I worked in the engine shop at American for 15 years, and we were
always told it was a very cost effective bird strike tool. But that is no
guarantee. We always did say if you hadn't heard a good rumor my 10:00 am,
then start one.

But then again, it shouldn't be needed by ground personnel. If someone can
look at a high bypass engine and tell if it's turning fast enough to be
dangerous, the need to be teaching English in France or something.