I am attempting to build a rank of Jazz Flute chimney pipes; that is,
half-stopped wooden flute pipes with a metal chimney on top.  These are
typically found on Mortier and Decap dance organs and pitched around
top C upwards.

I have a number of photographs of this type of pipe and I notice that
the chimney length does not appear to have a direct obvious relationship
with the length of the wooden body of the pipe.  It seems that the lower
notes have chimneys several times the length of the body, yet the higher
notes have chimneys almost the same length as the body.

Is there anyone among our readers who is able to explain the calculation
of the length (and diameter) of the chimneys to me please?

I am able to calculate the various dimensions of the pipe bodies for each
note but it is the chimneys that have me baffled and I don't have access
to a nearby dance organ where I can measure them.

Bob Essex
Warwickshire, England
http://www.bobessex.co.uk/