In my way-too-long Vienna trip report, I mentioned the unique organ
pipes in a large Viennese barrel organ.  I have Ord-Hume's new book on
restoring musical boxes and clocks, so I looked to see what I could find.
He mentions that Viennese flute-clocks may play "Vienna flutes" but
nothing more is said or shown.

The flute pipes I saw had a round hole for a mouth, about one hole
diameter up from the wind-way (flue), with the normal front surface
in between.  This appears to be a simulation of the German "transverse
flute", or "Querfloete", the forerunner of our modern concert flute, as
opposed to the recorder, or "Blockfloete".  A recorder is just an organ
pipe with finger holes, but the transverse flute requires a skilled
player's pursed lips to form the wind sheet.

An advantage of the Viennese design is that the pipe builder/voicer
need not adjust the flue to direct the wind sheet at the upper lip --
the front pipe surface will guide the wind sheet (which adheres to a
smooth surface) right over the hole.  The remaining variable is the flue
width (easy to tinker with) and the distance to the hole (also easy to
experiment with).

I'd like to hear from our Viennese and German musicologists and organ
lovers on this topic.  Why aren't these pipes found more widely?  My
guess it their tone is rather soft and too subdued for "monkey organs"
and fairground work, but should be ideal for indoor home use.

Time to go downstairs and try making one.

Mike Knudsen