FIRST STEPS TOWARD SPACE - Smithsonian Institution Libraries

44 SMITHSONIAN ANNALS OF FLIGHT
system with pressurized propellants was adopted,
but special bottles for the nitrogen tetroxide had to
be manufactured out of pure aluminum, in view of
the corrosiveness which could result from residual
traces of water. The chamber is shown schematically
in Figure 17. It incorporated several features of
present day rockets, such as the regenerative cooling
and the impinging jet injector. Credit for the practical
design of this chamber as well as of the other
equipment described in the rest of this paper goes
to Ing. G. Garofoli. The nozzle, including the convergent
part of the chamber, was cooled by fuel
cooling passages /; the rest of the chamber by the
oxidizer cooling passages S. The propellant flow
was hand-controlled by means of valves Rp and R0
located at the entrance of the cooling passages.
From the cooling ducts the propellants were
brought to the injector /, consisting of three concentric
annular injector slots, the central one, p,
for the fuel; the other two, O, for the oxidizer, resulting
in three impinging jets. Shown on the
figure is the rather unconventional use of a refractory
liner Z to decrease the heat transfer to the
chamber wall. The refractory material was zirconia,
chosen for its high melting temperature.
The whole chamber was built of stainless steel.
For the nozzle I had selected a steel developed in
the United States, because it could be welded.
Tungsten-arc welding was used, but the welding
was porous and gave lots of trouble. The complexity
of the chamber design was necessary to make
the chamber leakproof without welding. It was
manufactured out of a block of stainless steel from
COGNE Steelmills; so was the injector unit. Chamber
pressure and propellant injection pressures were
measured by gauges, as shown in Figure 17, and
the whole chamber was mounted on rollers to allow
the direct measurement of the thrust, which was
designed to be around 1250 g, at 10 atm chamber
pressure. The ignition sequence was rather involved.
A small gas torch v was first inserted into
the appropriate passage in the chamber walls.
Gaseous hydrogen and gaseous oxygen, provided
by an auxiliary feed system, were then admitted
through the propellant valves under very moderate
pressures, resulting in nearly atmospheric combustion.
The torch was then retracted, the torch passage
shut off, and the pressure of the gases gradually
increased until a noticeable chamber pressure
resulted. The transition to liquid propellants could
then be effected without difficulty.
This chamber was successfully tested late in
1930 by Dr. Landi and myself in a room on the
courtyard of the Institute of Chemistry of the University
of Rome, then located at via Panisperna. It
had been graciously assigned to our research, upon
my father's request, by his director, Professor Nicola
Parravano. I suppose that this decision of my father
of not carrying the tests within the laboratories of
the Air Ministry was dictated by the sponsoring
General Staff. During the ten-minute run our excitment
grew very high, reaching its climax with the
successful conclusion of the test. In our enthusiasm
we did not realize what an extraordinary noise
level we had introduced without warning in that
peaceful courtyard, all devoted to basic (and silent)
chemical research. What an anti-climax it was when
the noise subsided and we heard a loud voice asking
what in the h— was going on there. Dashing to the
windows we saw the angry and puzzled faces of
Professors Parravano, Malquori, and De Carli at
their respective windows. With an evident breach
of security we had to provide the technical background
for the deafening noise, after which Professor
Parravano had a meeting with my father. They
agreed that the project had to be transferred to a
more suitable location. A few weeks later, while in
his laboratory, Dr. Landi was suddenly struck and
died without regaining consciousness. I always
wondered whether his premature death (he was only
25) could have had something to do with his handling
of nitrogen tetroxide and too frequent accidental
inhaling of its toxic vapors. In which case,
Dr. Landi's name should deservedly be added to the
human life toll of rocket development.
With the death of one of the principal collaborators,
and the fact that I had to concentrate on
the preparation of my theoretical thesis for my
forthcoming degree in engineering (which I acquired
in July 1931); the research was temporarily
stopped. The available funds were exhausted, and
despite the promising results obtained, the General
Staff did not renew its contract.
Research on Monopropellants
Research was not resumed until the second half
of 1932, after I had graduated and satisfied my military
obligations. But in the meantime, as a result
of long and fruitful discussions between my father