Bob Cain wrote:

After it has ramped up from a stationary position to where it
is oscilationg with a constant motion superimposed on it, and after that
ramping up has passed an observer at some distance from the piston, he
will see no change in frequency but instead the same oscilation
superimposed on a constant air velocity (until the piston smacks him up
'long side the head if the constant motion is toward him.)

Ouch! That's dead wrong. Compass drift. With this problem
it is really difficult staying in the correct frame of
reference and when I wrote that I'd partially stepped off a
stationary one onto one that was moving, one foot still
firmly in each. :-)


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein