Yes, the Duo-Art fan accordion expression system that Spencer Chase
brought to the AMICA convention had some surprising and different
stuff in it.  I borrowed it, and am on my way to my machinist to have
it copied.

At this point I've located pieces of over 50 of these.  Early serial
dates on several (5) pianos (the above-keyboard drawer series) indicate
a 1928 installation, which would mean development of this complex item
took place in 1926-1927.  There is still reason to believe Tolbert
Cheek was involved, but no actual proof that I've seen.  Only the latest
ones seem to bear the clear imprint of our combined Aeolian/ American.

It appears to me that Aeolian was targeting several different markets:
the Concertola was one, the long-play lovers (I'm one) with both the
above-keyboard replacement long-play spool box and the below-keyboard
long-play drawer developed by American.  The most common fan system
(the one with the fans at either end) could be easily installed in a
spinet or an upright, though I've only heard on one such installation
and that was years ago when I was still laboring under the delusion
that the fans were a flop, and I didn't follow it up.

Also the above-keyboard action -- Many had options for varying the
Theme and Accompaniment volume curves which the 1927 manual does not
address, but then the '27 manual appears to be more of an introduction
for owners than a reference for factory-trained technicians.  There
must have been literature that dealt with how the various fan systems
could be set up to run, but as yet I have not seen copies.

Labeling them "Model B or C, etc." was premature, historically
inaccurate, and technically misleading.

I think everyone in 1930 thought the recession would pass in a year
or two; after all, "Boom & Bust" is how laissez faire had always worked
before.   No one expected the Great Depression; its depths, and the
real possibility of armed insurrection, were why the government of that
time had the support it did for regulating the economy as it did.  The
point being that I don't think these fan systems were just furtive (or
as some have insisted, "failed") attempts to produce something cheap.
Aeolian was positioning itself in the marketplace.

I'm running two different fan systems and find them delightful.  I love
how they are designed reinterpret the coding on the rolls.  Unlike the
B Ampico, they don't require specially coded rolls -- the whole library
works.  I've got several thousand, and that's a fact.

I also listened with great pleasure to several standard system Duo-Arts
at the AMICA convention (a 9'6" Steinway, and an upright Stroud).  Set
with care, standard systems can achieve 256 different volume gradations
for a single note.  It may be a step system, but with care it can do
a lot.  The fan is technically much more friendly, but then that's to
be expected when re-engineering takes place.

I may do a follow-up article for the AMICA Bulletin, but I hate to write.

Bruce Grimes