FIRST STEPS TOWARD SPACE - Smithsonian Institution Libraries

27
Annapolis Rocket Motor Development, 1936-38
I was bitten by the rocket bug at a very tender
age. As a high school student in the late 1920s and
early 1930s, I avidly read all the material available
in the local libraries in my home town of Alameda,
California. This included, as I remember, Goddard's
Smithsonian reports, the occasional articles
in Sunday supplements and accounts of the exploits
of Fritz von Opel and Max Valier which appeared
in such magazines as Popular Mechanics. Of course,
"Buck Rogers in the 25th Century" was my continuing
inspiration.
My first venture into the field of hardware was to
help a friend pry open shotgun shells to get out the
powder. This we poured into a tube inside a very
beautifully constructed balsa-wood rocket. When
the rocket exploded in a shower of flying splinters
and soda straws (rocket tubes), my friend proceeded
to build another beautifully painted model, but I
concentrated on making an engine that would
work. I tried paper tubes, small metal carbon
dioxide cylinders, etc., with the usual black powder
and gum arabic propellant formulations. I also
found old nitrate movie film to have interesting
properties. The rocket case for this propellant was
an old tooth-powder can. This one burst at a
height of several feet and scattered strips of flaming
celluloid all over my back yard.
My "thesis" in mechanical drawing during my
sophomore year in high school was a drawing of a
regeneratively cooled rocket motor, labelled Heylandt
Liquid Rocket, which I had never seen, but
of which I had read a description. 1
I count my significant work in rocketry from the
time I made my first engineering measurements on
an operating rocket engine. These measurements
were made during December 1937 on a thrust
chamber constructed earlier that year. The essential
R. C. TRUAX, United States
295
features of the thrust chamber are shown in Figure
1.
During this period, I was a midshipman at the
U.S. Naval Academy, subject to the severe restrictions
of time and opportunity associated with
studying at Annapolis. 2 There were, however, two
compensating advantages; the Naval Academy had
a machine shop, and across the Severn River from
the Academy was the U.S. Naval Engineering Experiment
Station.
During the 1935-36 period, I had designed a
liquid propellant sounding rocket embodying a
regeneratively cooled thrust chamber, tanks of seam
welded, 3/4-inch hard-rolled stainless steel, gyroscopic
controls, etc. 3 The thrust chamber shown in
Figure 1 was the first step toward development of
this sounding rocket. As can be seen, the design
involved regenerative cooling for the entrance section
of the nozzle, water film cooling at the throat,
and an uncooled metal diverging section.
The Naval Academy was not noted for the
amount of free time it gave to midshipmen, and
my rocketeering had to be sandwiched in between
the termination of classes and evening formation.
As a matter of fact, it developed that my time for
building rocketeering devices was even more restricted
because electric power in the shop was
turned off at 5 p.m.
After I had completed the design of the thrust
chamber in my room in Bancroft Hall, I went over
to Isherwood Hall to the machine shop to get on
with the job of fabrication. Mr. Harold Lucas, the
machinist in charge, listened sympathetically as I
explained my requirements for materials and then
asked me whether or not I had the proper requisitions.
Of course I had none, and after a somewhat
crestfallen silence on my part, Mr. Lucas offered