FIRST STEPS TOWARD SPACE - Smithsonian Institution Libraries

NUMBER 10 227
Max. inner diameter: 16.8 cm.
Max. O.D. combustion chamber: 30.0 cm.
Throat diameter: 5.03 cm.
Nozzle exit diameter: 8.4 cm.
Injection element configuration: 3 counterflow systems.
Max propellant capacity: 34 kg 02, 6 kg gasoline.
Stoichiometric propellant weights: 3.5 kg 02 (includes 62%
02 excess) + 1 kg gasoline — 4.5 kg.
Operational data:
Tank pressure 20 kg/cm 2 (gauge).
Combustion pressure 18 kg/cm 2 (gauge).
Burning time (full thrust) 32.5 sec.
Average thrust 250 kg.
Specific propellant consumption 6.8 kg/ton sec.
Propellant flow rate 1.7 kg/sec.
Propulsion system data:
Exhaust velocity: 805 m/sec.
Engine weight/impulse: 14.0 kg/ton sec.
Rocket stage data:
Tank and structural weight/impulse 240 kg/ton sec.
Air frame weight/impulse 26.0 kg/ton sec.
Seen historically, these tests with the 10-L rocket
indicated progress, at least with regard to the engine
development; but this did not suffice to maintain
operations of the Rocket Field and the Verein fiir
Raumschiffahrt. With the Magdeburg adventure,
the people in charge had gone too far! Not only did
they hurt their professional reputation by quackish
advertisement of a manned rocket flight and lose the
confidence of their contract partners because they
did not fulfill their promises regarding schedules
and performance for which they had been paid in
advance; they also lost complete control over their
finances by inadequate calculations and bookkeeping.
All this was sufficient reason for intervention by
those who had assumed political power in Germany
in the spring of 1933. Herbert Schaefer reported 21
that an inspector who supervised all activities was
assigned to the Rocket Field and, a short time later,
the Gestapo confiscated all journals and newspapers,
books, and working papers. In 1934, the
organization was dissolved and similar incorporations
prohibited. The most competent technician
and designer in the group was doubtlessly Klaus
Riedel, who was hired by Walter Dornberger, Chief
of the Sub-Office for Rocket Development in the
German Ordnance Department. The talented organizer
and spiritus rector of the group, Rudolf
Nebel, received a good sum of money as indemnification
payment.
From the military point of view, Walter Dornberger
gave the following account:
This office, to which problems of rocket development had
been transferred in 1929, was confronted at first by a muddle
difficult to straighten out. Neither industry nor the technical
colleges were paying any attention to the development of
high-performance rocket propulsion. There were only individual
inventors who played about without financial support,
assisted by more or less able collaborators. . Until
1932, no solid scientific research or development work was
done in this field in Germany . The Army Weapons Department
was forced to get in touch with the individual inventors,
support them financially, and await results. For two
years, the department tried in vain to obtain something to
go on. No progress was being made in the work. There was
also the danger that thoughtless chatter might result in the
department's becoming known as the financial backer of
rocket development. We had therefore to take other steps. As
we did not succeed in interesting heavy industry, there was
nothing left to do but to set up our own experimental
station for liquid-propellant rockets at the department's
proving ground in Kummersdorf near Berlin. We wanted to
have done once and for all with theory, unproved claims, and
boastful fantasy, and to arrive at conclusions based on a
sound scientific foundation. 22
Among the first members of the experimental station—besides
the then very young Wernher von
Braun and the mechanic Heinrich Griinow—were
two former employees of the Heylandtwerke,
Walter Riedel, a close collaborator of Max Valier,
and Arthur Rudolph, who, after Valier's death, had
continued with Alphons Pietsch the development
of Valier's "Standard Combustion Chamber."
The first engine, built at the end of 1932 by this
group according to Walter Riedel's suggestions, had
regenerative surface cooling, using fuel as coolant.
Dornberger described the engine:
The combustion chamber, with its round head and tapering
exhaust nozzle, was calculated to develop a thrust of 300
kg. On the right side of the measuring room . . a spherical
aluminum container with liquid oxygen was suspended. . . .
A similar container hung on the left-hand side. It contained
75 percent alcohol. The alcohol duct forked into two
branches, each connected to the bulbous edge of the exhaust
nozzle. Thin piano wires from the tanks led over rollers
through the concrete wall to instruments that would trace the
graphs of fuel consumption during firing. The rocket motor
itself had double walls. Between them rose cooling alcohol
at a high rate of flow from bottom to top. The alcohol,
warmed to 70° C, entered the inner chamber through small
sievelike injection nozzles in the chamber head. It was met
there by liquid oxygen ejected from a centrally placed brass
sprayer shaped like an inverted mushroom and perforated
with many small holes. 23