Here is a copy of a letter from Boris F. Kim, an acquaintance of Dr.
Clarence Hickman, inventor of the model B Ampico.

I do not believe that Dr. Hickman used his spark gap _camera_ to measure
speed of piano hammers.  Most likely it was the other way around.  He
developed the spark gap chronograph for Ampico, and most likely used the
spark gap principles on his camera.  Here is the letter:

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Hello Bruce,

I saw your post on rmmc about your Ampico memories.  I don't know much
about player pianos but I was an acquaintance of a man who was quite
influential in the development of the reproducing piano.  His name was
Clarence N. Hickman.

Dr. Hickman, who died about ten years ago, was an amazing person who had
many varied interests and contributed with his knowledge and
inventiveness to many diverse fields.  He was primarily a rocket
scientist and worked at the Bell Telephone Laboratories for most of his
professional career.

During the second world war, he was the head of a wartime project that
developed rockets; he in particular was the inventor of the bazooka
rocket launcher.  As part of his rocket research, he developed a high
speed camera (called a spark gap camera) that was capable of extremely
high frame rates for photographing rockets in flight.

Hickman was very interested in the sport of archery and is considered by
many the father of the science of archery, having made many seminal
studies both theoretical and experimental into the mechanics and dynamics
of the bow and arrow.  He used his high speed camera to photograph the
flight of an arrow as it leaves the bow and showed that the arrow bends
and vibrates in flight.  This phenomenon, which he discovered, is called
The Archer's Paradox.

Dr. Hickman was a consultant to the American Piano Company during their
development of the reproducing piano.  The specific problem that he
addressed was how to measure the velocity of a hammer striking the string
so that loudness could be accounted for in player pianos.  Here he made
use of his spark gap camera to measure the speed of the hammers.

I wasn't much interested in pianos when I knew Dr. Hickman, so
unfortunately I am not familiar with specific details of his work at
Ampico Research Laboratory.  I understand, however, that he designed an
action that was subsequently used in the reproducing pianos.

In July, 1979, Dr. Hickman (then in his 90's) was invited by AMICA to
give a talk on his work at Ampico.  The talk was given at the Ben
Franklin Hotel in Phila, Pa.  I was not present but I understand that the
talk was very well received; many in attendance sought his autograph on
books about player pianos.

Regards,  Boris

Boris F. Kim¶
Johns Hopkins University/APL¶
bkim@aplcomm.jhuapl.edu

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