From: "Barry L. Ornitz" <ornitz+U@dpnet.net>
Subject: Re: What tubes were used in proximity fuzes?
Date: 04 Apr 1999
Newsgroups: rec.antiques.radio+phono

joannnerumore@my-dejanews.com wrote in message
<7e7u5a$lvk$1@nnrp1.dejanews.com>...
about the proximity fuses uses in WWII.  The description of the capacitance
sensitive "superjenny"
was the correct method as was the breaking of a glass ampule to power a
dry-charged lead-acid battery.  While different people have noted that
different tube companies were involved, one name is likely not on
everyone's list:  Eastman Kodak.

Kodak's Apparatus Division, then called the Rochester Instrument Works,
actually built many of the proximity fuses.  They also built other radio
gear for the military too; I have a Kodak ARC-5 VHF receiver.  This lead to
a long partnership with the government in special projects.  [I have no
idea what the numbers are today, but in the early 1990's, Kodak's
Government Systems Division sold more in dollars to the military than did
most of the aviation manufacurers.]   Eastman Kodak's chemical
manufacturing arm, then Tennessee Eastman Company, was the prime contractor
for the nuclear project at Oak Ridge using the code name of Clinton Machine
Works.

When I went to work for Tennessee Eastman in 1980, I had the pleasure of
meeting and later working with James Henry.  He had worked for Kodak on the
development of proximity fuses, particularly the arming mechanism.  From
the description of the electronics, you can imagine what a difficult time
it would be to make such a shell power up in a stable state without going
off prematurely (and as noted, this still occurred more than it should
have).  Jim later went to Oak Ridge to work on the electromagnetic
separation process for separation of isotopes.  The electromagnets were
wound with silver wire loaned to the government by Kodak (who still likely
has the world's largest inventory of silver).  After the war, Jim remained
in east Tennessee working for Tennessee Eastman which is now an independent
company, Eastman Chemical Company.

Jim and I were both in the Engineering Research Division, and I was
fortunate to learn quite a bit from him.  His specialty was high speed
photography and strobe systems, and other instrumentation.  Jim had more
patents than the rest of our division combined.  And the funny thing was,
the government would periodically declassify a few of his wartime patents
and issue them.  Even after he retired, patents continued to trickle in -
on work done as much as 40 or more years earlier.  Following a long company
tradition, he was invited back every time this happened and given a silver
dollar as recognition.

Because of the secrecy issue he never discussed the design of proximity
fuses in detail.  He did say that the vacuum tubes were really not very
exotic.  In fact, they were pretty much like the peanut tubes used in
military and commercial gear right after the war.  They were soldered in
for reliability and shock mounted, but as someone else noted, they were not
especially ruggedized internally.  He noted that perhaps 90% of the
failures were atributed to the arming circuitry with the tubes only playing
a small part.

I suspect that there were many unsung heroes like Jim who did wonderful
things for the war effort, but whose accomplishments were never recognized
by historians.

        73,  Barry L. Ornitz     WA4VZQ     ornitz@dpnet.net