The late Dave Junchen, who had vast experience working with all sorts
of theatre organs and parts, told me in the 1960s that the pipes in
Wurlitzer Caliolas that he had seen were the same as Wurlitzer Tibia
Plena pipes used in theatre organs.

Ordinarily, Wurlitzer band organ pipes were different from theatre organ
pipes (for two completely different sounds), but the Caliola isn't
a band organ -- it's an air calliope that happens to share certain
mechanical parts and layout design with a late Wurlitzer band organ.

It would be interesting if someone who has access to both a Caliola and
a Wurlitzer pipe organ with tibia plena pipes could take some measurements
to see if Dave was making a generalized comparison or if both ranks
actually do have identical dimensions. The Tibia Plena rank is a large
scale open flute, while the familiar and more common Wurlitzer Tibia
Clausa is a large scale stopped flute, with an entirely different tone.

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